Survival In Triple-negative Breast Cancer Research Articles

Tumor-Infiltrating Lymphocytes in Patients With Stage I Triple-Negative Breast Cancer Untreated With Chemotherapy

The absolute benefit of chemotherapy for all patients with stage I triple-negative breast cancer (TNBC) is unclear, and biomarkers are not currently available for selecting patients with an excellent outcome for whom neoadjuvant or adjuvant chemotherapy may have negligible benefit. High levels of stromal tumor-infiltrating lymphocytes (sTILs) are associated with favorable survival in TNBC, but data solely in stage I TNBC are lacking. To examine the outcomes of patients of all ages with stage I TNBC solely and who received neither neoadjuvant nor adjuvant chemotherapy, according to centrally reviewed sTIL levels at prespecified cutoffs. This cohort study used the Netherlands Cancer Registry to identify patients diagnosed with stage I TNBC between January 1, 2005, and December 31, 2015, who were not treated with chemotherapy. Only patients who did not receive neoadjuvant and/or adjuvant chemotherapy were selected. The clinical data were matched with their corresponding pathology data provided by the Dutch Pathology Registry. Data analysis was performed between February and October 2023. The primary end point was breast cancer-specific survival (BCSS) at 5, 10, and 15 years for the prespecified sTIL level cutoffs of 30%, 50%, and 75%. Hematoxylin and eosin-stained slides were used for central review of histologic subtype, grade, and lymphovascular invasion. The International Immuno-Oncology Biomarker Working Group guidelines were used to score the sTIL levels; these levels were determined for 1041 patients. A total of 4511 females with stage I TNBC (mean [SD] age at diagnosis, 64.4 [11.1] years; median follow-up, 11.4 [95% CI, 10.9-11.9] years) were included. Most tumors (952 [91.5%]) were invasive carcinomas of nonspecial histologic subtype. Most patients (548 [52.6%]) had pT1cN0 tumors. Median (range) sTIL level was 5% (1%-99%). A total of 775 patients (74.4%) had sTIL levels below 30%, 266 (25.6%) had 30% or greater, 203 (19.5%) had 50% or greater, and 141 (13.5%) had 75% or greater. Patients with pT1abN0 tumors had a more favorable outcome vs patients with pT1cN0 tumors, with a 10-year BCSS of 92% (95% CI, 89%-94%) vs 86% (95% CI, 82%-89%). In the overall cohort, sTIL levels of at least 30% were associated with better BCSS compared with sTIL levels less than 30% (96% and 87%, respectively; hazard ratio [HR], 0.45; 95% CI, 0.26-0.77). High sTIL levels of 50% or greater were associated with a better outcome than low sTIL levels of less than 50% (HR, 0.27; 95% CI, 0.10-0.74) in patients with pT1C tumors, with a 10-year BCSS of 95% increasing to 98% with sTIL levels of 75% or greater. Results of this study showed that patients with stage I TNBC and high level of sTILs who did not receive neoadjuvant or adjuvant chemotherapy had excellent 10-year BCSS. The findings further support the role of sTILs as integral biomarkers in prospective clinical trials of therapy optimization for this patient population.

Triple-negative breast cancer survival prediction: population-based research using the SEER database and an external validation cohort.

Triple-negative breast cancer (TNBC) is linked to a poorer outlook, heightened aggressiveness relative to other breast cancer variants, and limited treatment choices. The absence of conventional treatment methods makes TNBC patients susceptible to metastasis. The objective of this research was to assess the clinical and pathological traits of TNBC patients, predict the influence of risk elements on their outlook, and create a prediction model to assist doctors in treating TNBC patients and enhancing their prognosis. We included 23,394 individuals with complete baseline clinical data and survival information who were diagnosed with primary TNBC between 2010 and 2015 based on the SEER database. External validation utilised a group from The Affiliated Lihuili Hospital of Ningbo University. Independent risk factors linked to TNBC prognosis were identified through univariate, multivariate, and least absolute shrinkage and selection operator regression methods. These characteristics were chosen as parameters to develop 3- and 5-year overall survival (OS) and breast cancer-specific survival (BCSS) nomogram models. Model accuracy was assessed using calibration curves, consistency indices (C-indices), receiver operating characteristic curves (ROCs), and decision curve analyses (DCAs). Finally, TNBC patients were divided into groups of high, medium, and low risk, employing the nomogram model for conducting a Kaplan-Meier survival analysis. In the training cohort, variables such as age at diagnosis, marital status, grade, T stage, N stage, M stage, surgery, radiation, and chemotherapy were linked to OS and BCSS. For the nomogram, the C-indices stood at 0.762, 0.747, and 0.764 in forecasting OS across the training, internal validation, and external validation groups, respectively. Additionally, the C-index values for the training, internal validation, and external validation groups in BCSS prediction stood at 0.793, 0.755, and 0.811, in that order. The findings revealed that the calibration of our nomogram model was successful, and the time-variant ROC curves highlighted its effectiveness in clinical settings. Ultimately, the clinical DCA showcased the prospective clinical advantages of the suggested model. Furthermore, the online version was simple to use, and nomogram classification may enhance the differentiation of TNBC prognosis and distinguish risk groups more accurately. These nomograms are precise tools for assessing risk in patients with TNBC and forecasting survival. They can help doctors identify prognostic markers and create more effective treatment plans for patients with TNBC, providing more accurate assessments of their 3- and 5-year OS and BCSS.

Comprehensive analysis of stereotactic Radiosurgery outcomes in triple-negative breast cancer patients with brain metastases: The influence of immunotherapy and prognostic factors

IntroductionBreast cancer stands as the second most common solid tumors with a propensity for brain metastasis. Among metastatic breast cancer cases, the brain metastasis incidence ranges from 10 % to 30 %, with triple-negative breast cancer (TNBC) displaying a heightened risk and poorer prognosis. SRS has emerged as an effective local treatment modality for brain metastases; however, data on its outcomes specifically in pure triple-negative subtype remain scarce. MethodWe retrospectively reviewed the electronic medical records of all brain metastasis (BM) TNBC patients treated with SRS. Patient, tumour characteristics and treatment details data were collected. This retrospective cohort study aimed to evaluate local control (LC), distant brain metastasis free survival (DBMFS), and overall survival (OS) outcomes in TNBC patients undergoing SRS for brain metastases while identifying potential prognostic factors. ResultForty-three patients with TNBC and brain metastases treated with SRS between January 2017 and 2023 were included. The study found rates of LC (99 % at 1 year) and DBMFS (76 % at 1 year) after SRS, with brain metastasis count (p = 0,003) and systemic treatment modality (p = 0,001) being significant predictors of DBMFS. The median OS following SRS was 19.5 months, with neurological deficit (p = 0.003) and systemic treatment modality (p = 0.019) identified as significant predictors of OS. ConclusionSRS demonstrates favourable outcomes in terms of local control and distant brain metastasis-free survival in TNBC. Neurological deficit and systemic treatment significantly influence overall survival, emphasizing the importance of personalized treatment approaches and (magnetic resonance imaging) MRI surveillance based on these factors.

Predicting locoregional recurrence in triple-negative breast cancer using novel molecular subtyping.

e12549 Background: Triple-negative breast cancer (TNBC) presents a poorer prognosis compared to other breast cancer subtypes, characterized by a higher likelihood of early recurrence and increased incidence of visceral metastases. Evidence from numerous randomized clinical trials indicates that postmastectomy radiotherapy (PMRT) reduces locoregional recurrence (LRR) and improves breast cancer survival in TNBC. Previous reports creatively divided TNBC into four molecular subtypes for personalized treatment. The present study aims to elucidate patterns of LRR in different subtypes of TNBC after PMRT. Methods: From 2019 to 2022, data from 349 AJCC 7th edition stage II-III breast cancer patients treated with mastectomy and PMRT were retrospectively analyzed. These patients were classified into the basal-like immune-suppressed (BLIS) and non-BLIS groups based on the immunohistochemistry biomarkers. The cumulative incidence function was applied to estimated LRR rates, with death as a competing risk, using Gray's test for comparisons. Results: According to the IHC results, a total of 255 patients belonged to the non-BLIS group and 94 to the BLIS group. The 3-year LRR for the entire cohort was 5.16%. There were 9 cases each in the non-BLIS subtype (3.5%) and BLIS subtype (9.6%). The cumulative incidence of LRR between the two groups was significantly different, with a rate of 4.0% in the non-BLIS group and 9.0% in the BLIS group ( P = 0.02). Among the 18 patients with LRR in the whole population, 11 had isolated LRR and 7 were diagnosed with LRR with concurrent distant metastases. The most common area of recurrence in both subtypes was the supraclavicular region. The majority of recurrences occurred within the RT field (in-field), and no isolated out-of-field relapse was observed. In multivariate analysis, independent factors predicting higher LRR were the BLIS subtype (HR = 3.06, P = 0.02). Conclusions: Study results suggest that TNBC of the BLIS subtype is at higher risk for LRR. Immunohistochemistry-based molecular typing may serve as a prognostic biomarker to guide postmastectomy radiotherapy in patients with TNBC. New strategies are needed to improve local control rates in patients with BLIS subtype.

Evaluation of a polygenic risk score as a predictor of early onset triple-negative breast cancer in Black women.

10501 Background: Black women in the U.S. often develop early, biologically aggressive breast cancer (BC). Triple-negative breast cancer (TNBC) is a particularly aggressive type that occurs more frequently in Black than white women and often develops before recommended regular screening. More accurate risk prediction methods are urgently needed to identify young Black women with elevated risk of TNBC. Incorporating polygenic risk scores (PRS) into clinical models can substantially improve risk assessment, but most PRS have demonstrated poor performance among non-European ancestries. We previously described a multiple-ancestry PRS (MA-PRS), based on 56 ancestry-informative and 329 BC-associated single-nucleotide polymorphisms (SNPs), that predicts overall BC risk for diverse populations by characterizing genetic ancestry at each BC SNP and applying ancestry-specific SNP risks and frequencies. Here, we evaluated the extent to which MA-PRS improves upon clinical factors for the prediction of TNBC and early onset ( < 50 years) TNBC in a large, independent cohort of self-reported Black women. Methods: We examined clinical and genetic records from self-reported Black women referred for hereditary cancer testing from 8/22 - 9/23 and negative for pathogenic variants in BC-associated genes. The association of MA-PRS with TNBC was analyzed using multivariable logistic regression adjusted for personal and family cancer history, age and genetic ancestry. Analyses were conducted within the full cohort and the subpopulation of patients < 50 years old. Odds ratios (OR) are reported per standard deviation (SD) with 95% confidence intervals (CI). Results: We identified 14728 Black women who met study eligibility criteria. Nearly 70% (9895/14728) of patients were under the age of 50. In the full cohort, 629 (4.3%) patients were diagnosed with TNBC, and 173 (1.7%) were younger than 50 years old. MA-PRS significantly improved TNBC risk prediction over clinical factors in the full cohort and in the subpopulation of women under 50 (Table). The effect of MA-PRS on risk stratification was comparable to the 1.4 OR per SD reported in current literature for mammographic density, which is widely recognized as an important risk factor. Women in the top 5% of the MA-PRS distribution were at roughly 2-fold increased risk of TNBC (Table). Conclusions: MA-PRS substantially improved upon clinical factors for the prediction of TNBC and early-onset TNBC in a large cohort of Black women. MA-PRS appears to be equally as important for managing risk of early-onset TNBC as mammographic density for overall BC. Incorporation of MA-PRS into BC risk assessment has the potential to improve TNBC survival through more accurate identification of women at high risk. [Table: see text]

Upregulation of collagen type X alpha 1 promotes the progress of triple-negative breast cancer via Wnt/β-catenin signaling.

Triple-negative breast cancer (TNBC) is a malignant tumor with high degree of malignancy and lack of effective target treatment. The research aims to explore the role and mechanism of X collagen alpha-1 chain protein (COL10A1 gene) in TNBC. UALCAN and Kaplan-Meier were used to detect the expression of COL10A1 and its role in the prognosis of breast cancer patients. The cells with stably expressing high levels of COL10A1 were obtained by recombinant lentivirus infection. The expression of COL10A1 in cells was temporarily downregulated by siRNA interference fragments. Real-time quantitative polymerase chain reaction and western blot analysis were utilized to detect the changes of COL10A1 mRNA and protein expression. The biological functions of the cells were evaluated by colony formation, cell counting kit-8, cell invasion and wound healing experiments. In addition, the effect of COL10A1 on angiogenesis was investigated by tube formation assay. Xenograft tumor model was used to confirm the effect of COL10A1 on tumorigenicity in vivo and multiplex fluorescent immunohistochemistry to detect multiple proteins simultaneously. The possible molecular mechanism of the function of COL10A1 was speculated through the detection of proteins in functionally related pathways. COL10A1 is highly expressed and is significantly associated with worse overall survival (OS) and recurrence-free survival (RFS) in TNBC. Overexpression of COL10A1 increased the clone formation rate and cell migration capacity of TNBC cells. In the COL10A1 overexpression group, the clone formation rates of MD-MB-231 and BT-549 cells (21.5 ± 0.62, 27.83 ± 3.72)% were significantly higher than those in the control group(15.23 ± 2.79, 19.4 ± 1.47)%, and the relative migration ratio (47.40 ± 3.09, 41.26 ± 4.33)% were higher than those in the control group (34.48 ± 2.03, 21.80 ± 1.03)%. When the expression of COL10A1 was downregulated, the ability of clone formation and wound-healing migration capacity in TNBC cells was weakened. Upregulated COL10A1 in TNBC cells generated more junctions and longer total segments between vascular endothelial cells, and promoted angiogenesis of the cells, and thus enhanced the tumorigenesis. In TNBC, it was found that COL10A1 might affect epithelial-mesenchymal transition (EMT) of the cells through Wnt/β-catenin signaling pathway by the detection of the related pathway proteins. COL10A1 is highly expressed in TNBC, and its high expression leads to poor OS and RFS. COL10A1 may enhance TNBC cell proliferation, migration and tumor-related angiogenesis, and promote tumorigenesis in vivo via Wnt/β-catenin signaling.

Exploring the prognostic significance of arm-level copy number alterations in triple-negative breast cancer.

Somatic copy number alterations (SCNAs) are prevalent in cancer and play a significant role in both tumorigenesis and therapeutic resistance. While focal SCNAs have been extensively studied, the impact of larger arm-level SCNAs remains poorly understood. Here, we investigated the association between arm-level SCNAs and overall survival in triple-negative breast cancer (TNBC), an aggressive subtype of breast cancer lacking targeted therapies. We identified frequent arm-level SCNAs, including 21q gain and 7p gain, which correlated with poor overall survival in TNBC patients. Further, we identified the expression of specific genes within these SCNAs associated with survival. Notably, we found that the expression of RIPK4, a gene located on 21q, exhibited a strong correlation with poor overall survival. In functional assays, we demonstrated that targeting Ripk4 in a murine lung metastatic TNBC model significantly reduced tumor burden, improved survival, and increased CD4+ and CD8+ T cell infiltration. RIPK4 enhanced the survival of triple-negative breast cancer cells at secondary sites, thereby facilitating the formation of metastatic lesions. Our findings highlight the significance of arm-level SCNAs in breast cancer progression and identify RIPK4 as a putative driver of TNBC metastasis and immunosuppression.

Lactylproteome analysis indicates histone H4K12 lactylation as a novel biomarker in triple-negative breast cancer.

The established link between posttranslational modifications of histone and non-histone lysine (K) residues in cell metabolism, and their role in cancer progression, is well-documented. However, the lactylation expression signature in triple-negative breast cancer (TNBC) remains underexplored. We conducted a comprehensive lactylproteome profiling of eight pairs of TNBC samples and their matched adjacent tissues. This was achieved through 4-Dimensional label-free quantitative proteomics combined with lactylation analysis (4D-LFQP-LA). The expression of identified lactylated proteins in TNBC was detected using immunoblotting and immunohistochemistry (IHC) with specific primary antibodies, and their clinicopathological and prognostic significance was evaluated. Our analysis identified 58 lactylation sites on 48 proteins, delineating the protein lactylation alteration signature in TNBC. Bioinformatic and functional analyses indicated that these lactylated proteins play crucial roles in regulating key biological processes in TNBC. Notably, lactylation of lysine at position 12 (H4K12lac) in the histone H4 domain was found to be upregulated in TNBC. Further investigations showed a high prevalence of H4K12lac upregulation in TNBC, with positive rates of 93.19% (137/147) and 92.93% (92/99) in TNBC tissue chip and validation cohorts, respectively. H4K12lac expression correlated positively with Ki-67 and inversely with overall survival (OS) in TNBC (HR [hazard ratio] =2.813, 95%CI [credibility interval]: 1.242-6.371, P=0.0164), suggesting its potential as an independent prognostic marker (HR=3.477, 95%CI: 1.324-9.130, P=0.011). Lactylation is a significant post-translational modification in TNBC proteins. H4K12lac emerges as a promising biomarker for TNBC, offering insights into the lactylation profiles of TNBC proteins and linking histone modifications to clinical implications in TNBC.

Abstract PO1-15-04: Young Black Women With Triple-Negative Breast Cancer Molecular Subtypes: Population-Specific Patterns and Batch Effect Considerations

Abstract Introduction: While triple-negative breast cancer (TNBC) molecular subtypes have been associated with biological differences and clinical outcomes, studies have overwhelmingly been conducted in populations of European or Asian ancestry. Data collected across diverse populations is required to better leverage clinical directions from translational studies in TNBC. Through females recruited through the Black Women: Etiology and Survival of Triple-Negative Breast Cancers (BEST) study, we sought to characterize subtypes and explore associations. Methods: Our study included Black women diagnosed with early-stage (I-III) invasive TNBC at < = age 50 from 2005 to 2016, with recruitment from Florida and Tennessee state cancer registries. Germline DNA, tumor RNA, clinical outcomes, and risk factor data were collected. TNBC status in the BEST study was based on immunohistochemistry from pathology reports, cancer registry data, and self-reported data. Analyses on banked tumor samples, extracted at multiple time points, were conducted through PAM50 (Nanostring) and whole-transcriptome RNA-seq. TNBC subtype was assessed using TNBCtype-4 (Lehmann et al. 2016). Sources of batch effect were evaluated using PCA and corrected via limma. Genetic ancestry based on OncoArray or MEGA genotyping data was inferred using 1000Genomes continental reference samples. Immune cell characterization was performed via CIBERSORT and ESTIMATE. Statistical significance in comparing differences across subtypes was assessed via Chi-square test. Kaplan-Meier estimates and log-rank test were used for survival analysis. Results: RNA-seq from 114 self-reported Black females with TNBC was analyzed. TNBC subtype distribution in the BEST study cohort included 31.6% basal-like 1 (BL1), 28.9% basal-like 2 (BL2), 16.7% luminal androgen receptor (LAR), and 21.9% mesenchymal (M). While results were largely consistent with prior studies in patients of European or East Asian ancestry, a higher percentage of BL2 subtype was observed (28.9% vs. 21.0%, p=0.053). Based on PAM50 subtyping, 100% of tumors with BL1 and M were basal, whereas 68.8% of LAR and 86.7% of BL2 subtypes were basal. Tumors without subtype decreased from 9.8% to 1.1% after batch correcting for location at which RNA was extracted (Moffitt vs. Vanderbilt) and time between RNA banking and sequencing. All TNBC subtypes in this population demonstrated monocyte/activated dendritic cell predominance, with no significant subtype-specific associations with immune cell patterns. A lower relative proportion of M subtype was found in tumors from BRCA1/2 carriers, but this was not statistically significant due to the small number of carriers (8% vs. 18%; p=0.22). With a median follow-up time of 9 years, there was no significant difference in 10-year overall survival by TNBC subtype (p=0.18). However, patients with M subtype appeared to have worse survival relative to other subtypes combined (p=0.036). Conclusion: Our study is among the largest to date that interrogates TNBC subtypes and associated molecular/clinical data in self-reported Black females with invasive breast cancer. Our findings suggest that established TNBC subtyping can be applied in patients of African ancestry. Furthermore, data to correct for lab-based confounders remains critical; in this study, it enabled us to use many samples that could not be subtyped initially. Several population-specific patterns were observed, including no difference in 10-year overall survival across TNBC subtypes (consistent with prior data), but worse initial outcomes in M subtype; a preliminary association between BRCA1/2 carriers and non-M subtypes (in contrast to prior data); and no significant difference in immune cell distributions (in contrast to prior data mainly from patients of European ancestry). Studies of associations between TNBC subtypes, additional clinical data, and treatment data (type and response rates) are ongoing. Citation Format: Padma Rajagopal, Sonya Reid, Run Fan, Lindsay Venton, Anne Weidner, Mya Roberson, Susan Vadaparampil, Xuefeng Wang, Sean Yoder, Marilin Rosa, Jibril Hirbo, Jennifer Whisenant, Jennifer Pietenpol, Fei Ye, Tuya Pal, Brian Lehmann. Young Black Women With Triple-Negative Breast Cancer Molecular Subtypes: Population-Specific Patterns and Batch Effect Considerations [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO1-15-04.

Abstract PO1-15-09: Vitamin A Metabolism Induces Ferroptosis to Enhance Immune Therapy Efficacy in HR+/HER2- Breast Cancer

Abstract Background: Immune checkpoint blockade (ICB) has substantially improved patient overall and progression-free survival in triple-negative breast cancer (TNBC), but its efficacy remains to be elucidated in the hormone receptor-positive (HR+)/human epidermal growth factor receptor 2-negative (HER2-) breast cancer, which is characterized by generally impotent lymphocytic infiltration. In the I-SPY2 trial (NCT01042379), pembrolizumab- or durvalumab-containing neoadjuvant therapy increased the pathologic complete response of HR+/HER2- patients. However, pembrolizumab-containing therapy failed to improve the survival of metastatic HR+/HER2- breast cancer patients (NCT03051659). These inconsistent results underscored the necessity of the investigation of predictive biomarkers to pinpoint potential ICB responders in HR+/HER2- breast cancer. Method: In this study, we collected pretreatment tumor samples from 16 patients in two respective clinical trials (NCT: 04215003 and 04355858) and profiled droplet-based single-cell sequencing, bulk RNA-Seq. Patients were treated with camrelizumab (PD-1 inhibitor)-containing therapy, and five of them achieved partial relief after an 8-week course. We also leveraged the bulk RNA-Seq data from the I-SPY2 trial and Fudan University Shanghai Cancer Center (FUSCC) TNBC ICB trials (NCT04418154 and NCT04613674) for external validation. Another FUSCC transcriptome dataset consisting of 933 treatment-naïve HR+/HER2- or TNBC breast cancer patients was used to detect the abundance of cell types. In vitro and in vivo experiments were used to explore mechanisms of anti-tumor immune response. Results: Based on the single-cell sequencing results, we comprehensively delineated the microenvironmental landscape of HR+/HER2- breast cancer. We discovered responders of immunotherapy showed a higher presence of CXCL9/10+ M1-like macrophages and exhibited enrichment of tumor cells with ferroptosis. We further identified the upregulation of vitamin A metabolism and the vitamin A metabolic gene CRABP1 in tumor cells with ferroptosis. We verified the vitamin A metabolism could induce ferroptosis in HR+/HER2- breast cancers rather than TNBC by CRABP1-ERK axis, which could further recruit CXCL9/10+ M1-like macrophages and promote anti-tumor immune response in HR+/HER2- breast cancer. Combining anti-PD1 with enhancing vitamin A metabolism via retinoid acid possessed greater therapeutic efficacy than monotherapy in HR+/HER2- breast cancers. Finally, we developed an immune therapy response score and validated its reliability in predicting the immunotherapy efficacy for HR+/HER2-breast cancers through both internal and external cohorts. Conclusion: Our study represents the earliest efforts to decipher the microenvironmental landscape and the mechanisms underlying the response to ICB in HR+/HER2- breast cancer at single-cell resolution. We unraveled a HR+/HER2- breast cancer-specific Vitamin A-ferroptosis axis that mediated immunotherapy response and constructed a robust immunotherapy efficacy prediction score based on this Vitamin A-ferroptosis axis. Citation Format: Yi-Fan Zhou, Hu-Yun-Long Zhang, Xi Jin, Yi-Zhou Jiang, Zhi-Ming Shao. Vitamin A Metabolism Induces Ferroptosis to Enhance Immune Therapy Efficacy in HR+/HER2- Breast Cancer [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO1-15-09.

Abstract PO5-13-07: Prediction of recurrence in triple negative breast cancer patients after receiving neoadjuvanttreatment using plasma metabolomics

Abstract Background Early-stage triple-negative breast cancer (TNBC) is usually treated with neoadjuvant chemotherapy (NADC), but prognosis remains poor compared with other BC subtypes. Unfortunately, less than 30% of BC patients achieve pathological complete response (pCR) to NADC and the overall survival of TNBC when cancer spreads is estimated at 10-13 months. Complete response is associated with improved progression-free and overall survival rates, but more accurate prognostic markers are needed. In this study, we assessed the prognostic value of blood circulating metabolites by using targeted-based metabolomics. Methods Patients received standard neoadjuvant chemotherapy with epirubicin plus cyclophosphamide followed by paclitaxel. Blood samples were obtained upon completion of chemotherapy and before surgery. Pathological response to treatment was recorded according to the Miller & Payne system, and categorized as partial (MP 1, 2, & 3) or complete response (MP 4 & 5). Blood samples were collected in EDTA tubes, centrifuged and plasma was stored at -80°C. After QC standard addition and methanol extraction of proteins, four fractions of the resulting extract were analysed: two by reverse-phase/UPLC-MS/MS methods with positive ion mode electrospray ionization (ESI), one by reverse phase/UPLC-MS/MS with negative ion mode ESI, and one by hydrophilic interaction liquid chromatography/UPLC-MS/MS) by Metabolon using a Thermo Scientific Q-Exactive mass spectrometer with a heated electrospray ionization source and an Orbitrap mass analyser. Using Metabolon's hardware and software, raw data were extracted, identified, QC processed and quantified using the area under the curve (AUC). Identified compounds were compared with library entries of purified standards or recurrent unknown entities. The prognostic capacity of each metabolite was assessed using BRB ArrayTools. Selected metabolites were validated using a targeted approach using compound standards as follows. Plasma samples were re-analysed by UPLC/MS using a Vanquish LC coupled to an Orbitrap Exploris 240 MS (Thermo Fisher Scientific) with positive and negative ionization mode ESI under polarity switching. Identification of compounds were performed by comparison of retention times (against in-house authentic standards), accurate mass (with an accepted deviation of 3ppm), and MS/MS spectra. These analyses were carried out by MS-Omics (Denmark). Results Twenty patients treated in the Medical Oncology Unit of the University Hospital of Jaén were recruited. Median age was 50 (31-76). Twelve patients obtained a pathological complete response. Median follow-up after surgery was 25 months. Seven patients eventually had distant metastases (2 in the lungs, 1 in the brain, 1 in the bones and 3 multi-site). Metabolon untargeted analysis identified and quantified 985 metabolites, 789 after xenobiotics exclusion. Survival analysis identified 16 metabolites related with distant relapse (p< 0.05). The ten metabolites with lower p-value were selected for targeted validation. Ms-Omics pipeline allowed absolute quantification of 5 metabolites, 3 of them showing high correlation (R >0.7) between both measurements (targeted and untargeted). Validation of the prognostic value of the candidate metabolites is ongoing in a larger TNBC cohort. Conclusions Metabolomics is a useful tool for the detection of simply assessable and cost-effective prognostic biomarkers in TNBC. Easily monitoring the presence of minimal residual disease is worth to be settled up in the clinical practice for the most aggressive molecular subtype of breast cancer. In this work we have defined a set of metabolites that could predict distant relapse events in TNBC patients treated with neoadjuvant chemotherapy. Further analyses are being carried out to validate the prognostic value of the proposed candidate metabolites. Citation Format: Pedro Sánchez-Rovira, Rocio Urbano-Cubero, Angelo Gamez Pozo, Carmen González-Olmedo, Alicia Cano-Jimenez, Andrea Zapater- Moros, Leticia Díaz-Beltrán, Lucia Trilla-Fuertes, Mariana Díaz-Almirón, Enrique Espinosa, Pilar Zamora, Juan Angel Fresno Vara. Prediction of recurrence in triple negative breast cancer patients after receiving neoadjuvanttreatment using plasma metabolomics [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO5-13-07.

Abstract PO5-17-01: Pre-treatment tumor infiltrating lymphocytes are associated with higher likelihood of pathologic complete response among black women with TNBC receiving neoadjuvant chemoimmunotherapy

Abstract Background: High risk, early-stage triple negative breast cancer (TNBC) is a heterogenous disease that is associated with early recurrence and high mortality, particularly among black women as compared to their white counterparts. Pathologic complete response (pCR) to neoadjuvant chemotherapy (NACT) is a strong-predictor of long-term disease-free survival in TNBC, and the KEYNOTE-522 trial demonstrated that the addition of immunotherapy (pembrolizumab) to NACT resulted in a higher likelihood of pathologic complete response (pCR) in high-risk early-stage TNBC. Following these findings, the standard of care has been to administer the K522 regimen (K522R) in the neoadjuvant setting for patients with high risk early-stage TNBC. However, our understanding of the clinical and tumor characteristics to prognosticate response to K522 are lacking, and additional real-world data is needed to better understand if these variables differ among race. Methods: We evaluated 76 patients who were treated with the K522R at our institution. There were slides available from 29 patients’ pre-treatment biopsies for pathology review. In the available slides, tumor infiltrating lymphocytes (TIL) were evaluated as the percentage of lymphocytes in the stroma within the tumor area. For the remaining cases that did not have available slides, these variables were retrieved from pathology reports and patients’ charts. Patient characteristics including age, race and body mass index (BMI) were acquired via retrospective chart review. These clinicopathologic variables were correlated with pCR, which was defined by the absence of invasive carcinoma in the breast and axillary lymph nodes at the time of surgery. Binary logistic regression analysis was performed to correlate the above variables with pCR versus residual disease (RD). Results: Seventy-six pre-treatment biopsy specimens treated with the K522R were evaluated. The patient population spanned a broad spectrum of age, body habitus, and race, with mean age 55, mean BMI 28.3, and predominantly black (over 60 percent) population. At the time of analysis, 64 of the 76 patients had completed the K522R and subsequently undergone surgery at our institution. Of the 64 patients who had undergone definitive surgery, 31 (48.4%) achieved pCR. In univariate analysis, pre-treatment TIL was significantly associated with attainment of pCR, with TIL of 28.5% (± 19.1) in patients who achieved pCR versus 9.73% (± 9.40) in those who had RD (95% CI 1.03-1.21, p=0.014*). When TIL was further stratified by race, mean percentage of TIL was significantly higher among black women who achieved pCR (27.5% ± 4.7) compared to black women with RD (12.2% ± 3.05) (95% CI 0.021 – 0.197, p=0.016*). Additionally, mean percentage of TIL was higher overall among black women when compared to the white patients in our cohort, though this finding was not statistically significant (p=0.252). Conclusion: Our real-world data demonstrates high levels of pre-treatment TIL are significantly associated with achievement of pCR in patients with TNBC treated with the K522 regimen. When TIL was further stratified by race, black patients were found to have higher TIL than white patients. Within the black population, a statistically significant difference in TIL percentage was found in those achieving pCR compared to those with RD. It is well understood that black women often have poorer breast cancer outcomes than white women, and our finding of higher TIL percentage among this population, along with the significant association between TIL and attainment of pCR with chemoimmunotherapy, could have important implications for optimization of therapy. Further exploration of this phenomenon in larger, diverse breast cancer populations is warranted. Citation Format: Sarah Wood, Ji-Hoon Lee, Yuan Gao, Xiaoxian Li, Jane Meisel. Pre-treatment tumor infiltrating lymphocytes are associated with higher likelihood of pathologic complete response among black women with TNBC receiving neoadjuvant chemoimmunotherapy [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO5-17-01.

Abstract PO2-13-04: Single cell characterization of senescent CD8+ T cell promotes immunotherapy resistance in early-stage triple-negative breast cancer

Abstract Background: Immune checkpoint blockade (ICB) has been explored in triple-negative breast cancer (TNBC) and has been proven to improve patient survival in advanced TNBCs (IMpassion130) or increase the pathological complete response rate in early TNBCs (KEYNOTE522). However, ICB could only benefit a subset of patients, highlighting the urgent need to optimize patient selection. Unlike in advanced TNBCs, a predictive biomarker for ICB in early TNBCs is still lacking. The main reason might be that previous studies neglected the heterogeneity of tumor ecosystems between early and advanced TNBCs. There is an urgent need to understand the unique ecosystem of early-stage TNBC and develop biomarkers for precision immunotherapy. Objective: This study aims to characterize the micro-loop associated with the immune efficacy of early TNBC, so as to explain the mechanisms behind the differences in early and late efficacy markers, identify efficacy markers in early TNBC immunotherapy, and search for clinical targeting strategies to sensitize TNBC for neoadjuvant therapy. Methods: We conducted an in-depth analysis of 32 single-cell transcriptomes, comprising 26 early-stage TNBC enrolled in prospective clinical trials (NCT04418154 and NCT04613674), receiving neoadjuvant chemotherapy alone (n=8) or combined with anti-PD1 (n=18), and 6 advanced TNBC. We analyzed the microenvironmental differences between early and advanced tumors, and between different treatment response groups in early stages, and identified a subpopulation of cells specific to early stages and associated with immunotherapeutic efficacy. We used mIHC, flow-through, and validated the presence of this cell in clinical samples. We also explored its predictive performance on four independent cohorts of TNBCs with ICB treatment (GSE194040, NCT04129996, GSE169246, GSE124821). Furthermore, to understand the impact of ISG+ T cells on immunotherapy efficacy and explore targeting strategies, we employed a multi-faceted approach to assess their tumor-killing ability, response to Anti-PD1 treatment, and sensitization effect of drugs targeting ISG+ T cells. ISG+ T cells were sorted using flow cytometry for further experiment. In vitro, we established a co-culture model of primary TNBC patients-derived organoid (PDO) and tumor infiltrated CD8+T cells and evaluated the tumor cell viability as well as T cell cytotoxicity. In vivo, we established TS/A tumor cell bearing BalB/c mouse and E0771 tumor cell-bearing C57BL mouse and measured tumor size and tumor microenvironment by flow cytometry. Results: We obtained 236,017 high-quality cells and identified cell subsets across 32 samples with different stages, treatments and responses. We then uncovered an enriched subset of interferon-induced (ISG+) CD8+ T cells specific to early TNBC, serving as a predictive factor for ICB resistance. Mechanistically, the upregulation of the IFN pathway in early-stage TNBC triggers a transition in ISG+ CD8+ T cells, resulting in cellular senescence, diminished cytotoxicity, and impaired response to ICB. Encouragingly, we made a noteworthy discovery that Nicotinamide mononucleotide, an anti-aging drug, effectively restores the functionality of ISG+ CD8+ T cells, amplifying immunotherapy sensitivity. Conclusions: This study provided a comprehensive single-cell transcriptome atlas of early-stage TNBC and depicted stage-related ISG+CD8+ T cell for predicting ICB response in early TNBC. We emphasize the critical role of T cell dysfunction prompted by cellular senescence in driving ICB resistance during the early stages of TNBC and propose an approach for sensitizing immunotherapy with aging drugs. Citation Format: Tong Fu, Yi-Yu Chen, Xi Jin, Yi-Zhou Jiang, Zhi-Ming Shao. Single cell characterization of senescent CD8+ T cell promotes immunotherapy resistance in early-stage triple-negative breast cancer [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO2-13-04.

Abstract PO1-29-01: Single agent and combinatorial efficacy with imipridone ONC206 via inhibition of mitochondrial function in preclinical models of chemorefractory triple negative breast cancer

Abstract Breast cancer remains a major global health concern, with triple-negative breast cancer (TNBC) being one of the most aggressive subtypes associated with limited targeted therapies. Chemotherapy resistance in TNBC patients poses a significant clinical challenge and is associated with poor progression-free and overall survival. Thus, exploring novel approaches to improve chemotherapeutic efficacy is of paramount importance. We previously demonstrated a role for mitochondrial fusion in supporting oxidative phosphorylation (oxphos) activity and cell survival in residual TNBC (PMID: 30996079 and 36813854) cells refractory to chemotherapy treatments. Based on these observations, we sought to inhibit mitochondrial function to improve chemotherapeutic efficacy. We used ONC206, a novel agonist of mitochondrial serine protease, ClpP (Caseinolytic Mitochondrial Matrix Peptidase Proteolytic Subunit) to induce mitochondrial proteotoxic stress. ONC201, a parent molecule of ONC206, has shown efficacy in TNBC as a single agent or when combined with a MEK inhibitor in vitro (PMID: 34680527). We demonstrate treatment of TNBC cell lines with ONC206 results in reduced mitochondrial fusion and OXPHOS. Furthermore, ONC206 co-treatment enhanced chemo-sensitivity in vitro. Based on these promising findings, we tested this in orthotopic patient-derived xenograft (PDX) mouse preclinical trials. Three PDX models of TNBC were tested, BCM-2665, BCM-5471, and BCM-0002. ONC206 as a single agent (twice weekly for 4 weeks, oral gavage, 100mg/kg) significantly decreased tumor growth in all three PDX models. Remarkably, treatment ONC206 achieved nearly complete tumor regression as a single agent or when combined with carboplatin in BCM-2665. Regressed tumors did re-grow, but this was significantly delayed when combined with carboplatin. Treatment with ONC206 in BCM-5471 resulted in a modest but significant reduction in tumor growth rate as a single agent. However, ONC206 did not improve carboplatin (weekly, i.p., 50mg/kg) nor docetaxel (weekly, i.p., 20mg/kg) efficacy in this model. ONC206 treatment of BCM-0002 resulted in prolonged tumor stasis and a slight enhancement of docetaxel and carboplatin efficacy. Interestingly, the efficacy of ONC206 in these PDX models correlates with their relative mRNA expression of ClpP. The mice demonstrated tolerance to ONC206 as a single agent or when combined with chemotherapy during the course of treatment. Our study underscores the potentially crucial role of mitochondria in driving chemotherapy resistance in TNBC and provides novel insights into mitochondria-targeted therapeutic approaches. We report a novel targeting option for TNBC and anticipate that these findings will stimulate further research into innovative combination therapies for TNBC patients, and may lead us to a viable inhibitor. Citation Format: Lily Baek, Lacey Dobrolecki, Stefanie Faucher, Christina Sallas, Nia Griffith, Varun Prabhu, Bora Lim, Michael Lewis, Gloria Echeverria. Single agent and combinatorial efficacy with imipridone ONC206 via inhibition of mitochondrial function in preclinical models of chemorefractory triple negative breast cancer [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO1-29-01.

Abstract 2269: Dual targeting of the PI3K-AKT pathway in triple-negative breast cancer

Abstract PIK3CA mutations occur in ~15% of triple-negative breast cancers (TNBCs) and aberrantly activate the PI3K-AKT pathway, resulting in uncontrolled cell proliferation. Alpelisib is approved for hormone receptor-positive (HR+), HER2-negative BC patients with a PIK3CA mutation; however, not all PIK3CA-mutated (MUT), HR+ patients respond to alpelisib and others acquire resistance following exposure, suggesting adaptive mechanisms of PI3K activation. It has been proven that in TNBC, there exists a cohort of mutated genes which activate PI3K-AKT signaling. We hypothesize that testing alpelisib in combination with repurposed approved drugs, targeting alternative mechanisms of PI3K-AKT pathway activation, may be used to treat a cohort of TNBC patients. TNBC patient genetic data from the MSK (N=168), METABRIC (N=209), and TCGA (N=171) datasets were analyzed using cBioPortal to identify frequently occurring mutations. Differential expression analyses based on mutational status were performed on CCLE cell line (N=705) microarray and TCGA BC patient (N=981) RNA-sequencing data using R. Dysregulated genes were functionally analyzed using DAVID Ontology and those associated with poorer survival in TNBC were identified using KM-Plotter. STRING database was used to investigate protein interactions. The antiproliferative effects of targeted drugs tested alone and in combination in a panel of 6 TNBC cell lines were determined using acid phosphatase assays. Reverse-phase protein array analysis was carried out on protein lysates from cells following 24 hour treatment with drugs used alone and in combination.TP53 is the most frequently mutated gene in TNBC and mutations were associated with significant genetic dysregulation. A comprehensive analysis of upregulated genes in TP53-MUT TNBC led to the identification of 5 potential therapeutic targets - MET, S100A9, LCN2, CA9, TACSTD2, and KLK5 - based on their association with poorer survival in TNBC, protein interactions with TP53 and PIK3CA, and availability of targeted drugs. MET was selected for in vitro analysis based on its strong correlation with PI3K-AKT signaling. The presence of a TP53 mutation was associated with decreased antiproliferative effects in TNBC cell lines treated with alpelisib. Treatment with alpelisib in combination with a MET inhibitor, crizotinib, demonstrated greater antiproliferative effects in TP53-MUT/PIK3CA-MUT cell lines when compared to TP53 or PIK3CA MUT only models.TP53 mutations are associated with genetic dysregulation in TNBC and may confer resistance to alpelisib. Targeting upregulated proteins in a cohort of TP53-MUT/PIK3CA-MUT patients may improve sensitivity to alpelisib via dual inhibition of PI3K-AKT pathway activation. Protein analysis will uncover the mechanisms of synergy observed between alpelisib and crizotinib, and the therapeutic potential of the combination will be experimentally investigated in vivo. Citation Format: Grace Colley, Alexander Eustace, Dalal AlSultan. Dual targeting of the PI3K-AKT pathway in triple-negative breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2269.

Abstract 5417: PHGDH expression level impacts tumorigenesis and metastasis in human breast cancer

Abstract Background: Phosphoglycerate dehydrogenase (PHGDH) is a metabolic enzyme, which is associated with the first step of serine synthesis. The gene encoding this enzyme is often elevated in some types of human cancer, including breast cancer. There are some researches that High-PHGDH expression promotes cancer cell proliferation and tumorigenesis. However, latest study showed that although breast tumors with high expression levels of PHGDH had more possibility to undergo primary-tumor growth, were less likely to metastasize than tumors with low expression of PHGDH by using mouse cell derived mouse models and PDX models. Nevertheless, the applicability of these outcomes to human breast cancer cell lines remains uncertain. Methods: The survival analysis according to PHGDH mRNA expression was analyzed in METABRIC datasets of breast cancer and the whole-transcriptome sequencing data of 120 breast cancer patients. To investigate the effect of PHGDH in human TNBC cell lines, PHGDH overexpressing MDA-MB-231 cell lines and PHGDH knockdown MDA-MB-468 cell lines were established. Subsequent functional experiments were performed to explore the influence of PHGDH on breast cancer tumorigenesis and metastasis. Results: In the analysis using METABRIC datasets, overall survival and disease-free survival were reduced in patients with high PHGDH expression and basal type breast cancer showed the highest mRNA level of PHGDH. Using whole-transcriptome sequencing data of 120 breast cancer patients, we also found PHGDH expression level was higher in cancer tissue(n=120) than normal tissue(n=90). In particular, triple-negative breast cancer indicated higher PHGDH level than luminal type breast cancer. We also used this data to perform analysis of overall survival, disease-free survival, metastasis free survival of non-TNBC patient and it resulted in reducing survival rate when patient showed high-PHGDH expression. However, TNBC patients demonstrated diametrical results in the identical analysis. We examined the impact of PHGDH overexpression in MDA-MB-231 cells and PHGDH knockdown in MDA-MB-468 cells, observing increased proliferation and decreased migration in breast cancer cells with elevated PHGDH levels. Conversely, PHGDH knockdown exhibited opposing effects. Subsequently analysis of markers associated with epithelial-mesenchymal transition revealed a correlation with PHGDH expression. Conclusions: Our data suggest that a potential role for PHGDH in breast cancer as a marker of reduced survival in triple-negative breast cancer, and as a regulator of cancer cell proliferation and metastasis. Citation Format: Jihong Baik, Juhee Kim, Sangeun Lee, Ayoung Park, Kyoungseob Shin, Sunghoon Kwon, Hanbyoel Lee, Wonshik Han. PHGDH expression level impacts tumorigenesis and metastasis in human breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5417.

Abstract 7660: L-Arginine metabolism is of prognostic relevance in women with breast cancer, but varies considerably between subtypes in vitro - A bedside-to-bench translational approach

Abstract Availability of the semi-essential amino acid L-arginine (L-arg) is limiting for proliferation in highly proliferative tissues. L-Arg is also a substrate for nitric oxide synthases (NOS) and arginases (ARG) 1 and 2. Methylation of L-arg residues within proteins by protein L-arg methyltransferases (PRMTs) leads to asymmetric (ADMA) and symmetric dimethylarginine (SDMA). Protein L-arg methylation is an important post-translational mechanism to regulate gene expression and cell cycle control. We measured L-arg and its metabolites in a prospective cohort of patients with primary breast cancer (BC). We further measured these metabolites and expression of genes involved in L-arg metabolic pathways in cell lines representing intrinsic BC subtypes. Plasma L-arg-related metabolite concentrations from 243 women with primary BC were associated with total mortality and disease recurrence during a median follow-up of 88 (IQR, 82-93) months. MCF-7, BT-474, SK-BR-3, and MDA-MB-468 cells representing ER-positive, HER2-positive, and triple negative BC were cultured in standard conditions and compared to MCF-12A normal breast epithelial cells. The plasma (in vivo) and intracellular concentrations (in vitro) of L-arg, L-ornithine (L-orn), L-citrulline (L-cit), ADMA, and SDMA were measured by UPLC-MS/MS. mRNA expression was quantified by qRT-PCR and protein expression was analyzed by Western Blot. In vivo, the plasma concentrations of all L-arg metabolites differed significantly between BC patients and healthy controls. L-Arg and ADMA were significantly higher in patients with recurrent disease and in those who died during follow up. ADMA was significantly associated with total mortality and recurrent disease in Luminal A patients; low L-orn/L-arg ratio was associated with survival in HER2+ BC patients, and low L-cit was associated with survival in triple negative BC. With the exception of MCF-7 cells, DDAH1 and DDAH2 mRNA concentrations in vitro were significantly higher in BC cells than in MCF-12A cells (DDAH1: 32-44 fold, DDAH2: 1.7-4.2 fold; p<0.05). These differences were mirrored by DDAH1 and DDAH2 protein concentrations. By contrast, MCF-7 cells were characterized by low DDAH1 and DDAH2, but high PRMT4 and PRMT6 mRNA expression and high L-arg content. BT-474 cells showed high ARG2 expression and high L-arg and L-orn concentrations, and MDA-MB-468 cells had the highest L-cit/L-arg ratio. In conclusion, regulation of L-arg metabolic pathways shows a complex and differential pattern between intrinsic BC subtypes, which is mirrored in representative cell lines in vitro. ADMA is a prognostic biomarker in Luminal A breast cancer patients; its metabolizing enzyme, DDAH, is highly overexpressed in BC cells in vitro. Thus, fingerprinting of L-arg metabolism may offer novel personalized treatment options within intrinsic BC subtypes. Citation Format: Juliane Hannemann, Leticia Oliveira Ferrer, Antonia Röglin, Fiona Kleinsang, Volkmar Müller, Isabell Witzel, Rainer Böger. L-Arginine metabolism is of prognostic relevance in women with breast cancer, but varies considerably between subtypes in vitro - A bedside-to-bench translational approach [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 7660.

Abstract 2099: PELP1 inhibition enhances the therapeutic efficacy of topoisomerase inhibitors in triple-negative breast cancer

Abstract BACKGROUND: Triple negative breast cancers (TNBCs) account for 15-24% of breast cancer deaths and are characterized by aggressive clinical course, a worse prognosis, and a higher propensity to metastasize. Proline, glutamic acid-, and leucine-rich protein 1 (PELP1) is an oncogene, its expression is deregulated in TNBC, and its status is a prognostic indicator of poor TNBC survival. Recently, a small molecule inhibitor of PELP1 (SMIP34) which binds to and degrades PELP1 was developed. The Objective of this proposal is to define the mechanism of action of PELP1 inhibitor SMIP34 in TNBC progression and to pave the path for a novel combination therapy. METHODS: We tested the effectiveness of PELP1 inhibitor, SMIP-34, in combination with 140 FDA-approved medications on cell survival of multiple TNBC cell lines. The effect of SMIP34 combination therapy on cell survival was measured using MTT, colony formation, and Annexin V apoptosis assays. Mechanistic studies were done using RT-qPCR, immunoprecipitation, proximity ligation, mass spectrometry, gene reporter, immunofluorescence, and comet assays. Furthermore, the preclinical utility of combination therapy was evaluated using MDA-MB-231 xenografts, patient-derived organoids (PDOs) and explants (PDEs). RESULTS: We performed an in vitro screening of 140 FDA-approved drugs in combination with SMIP34. Results revealed that SMIP34 sensitized TNBC cells to five FDA approved drugs. Of the five drugs, the three drugs Gemcitabine, Valrubicin, and Mitoxantrone, induced DNA damage by inhibiting topoisomerase, a protein that cleaves and reconnects DNA during replication. We validated the ability of SMIP34 to enhance the efficacy of TIs using two additional TNBC cell lines and confirmed their synergistic activity using several in vitro assays including cell viability, colony formation, and apoptosis. In agreement with the role of PELP1 in DNA damage response, Western blotting analyses showed higher levels of γ-H2AX in SMIP34+TI combination therapy when compared to monotherapy. Results from the comet assays further demonstrate increased DNA damage caused by the SMIP-34 + TIs combination therapy. Mechanistic studies using Proximity labelling followed by immunoprecipitation identified topoisomerase 2A and 2B (TOP2A and TOP2B) as potential interactors of PELP1. Furthermore, gene correlation analysis using TCGA datasets revealed that PELP1 expression is positively correlated with TOP2A, and TOP2B in TNBC. SMIP34 plus Mitoxantrone (TI) combination treatment significantly reduced the growth of TNBC PDEXs, and PDOs in vitro, and MDA-MB-231 xenograft tumor growth in vivo, compared to vehicle or monotherapy treatment. CONCLUSION: Together, these results suggest a novel targeted therapy for the treatment of TNBC, involving the combination of topoisomerase inhibitors and the PELP1 inhibitor SMIP34. Citation Format: Khaled Mohamed Nassar, John R. Sanchez, Durga Meenakshi Panneerdoss, Behnam Ebrahimi, Yang Xue, Uday P. Pratap, Salvador C. Alejo, Gangadhara R. Sareddy, Suryavathi Viswanadhapalli, Ratna K. Vadlamudi. PELP1 inhibition enhances the therapeutic efficacy of topoisomerase inhibitors in triple-negative breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2099.

Abstract 5363: New targeted therapy on SOCS1-related immune-response in triple-negative breast cancer

Abstract Background: Triple-negative breast cancer (TNBC) is heterogenous, which includes basal-like, immunomodulatory, mesenchymal, mesenchymal stem cell and luminal androgen receptor subtypes. In addition to chemotherapy, PARP inhibitors and immune checkpoint inhibitors are effective for TNBC with BRCA-mutated and PD-L1-positive cases. However, overall survival of TNBC remains unfavorable. To explore new targeted therapy in TNBC, we reported previously that SOCS1 (suppressor of cytokine signaling 1), IL-13 and several genes were predicted as interactive targets of miRNA in TNBC from the microarray expression analysis (Agilent Technologies, Inc.) of small RNA extracted from 11 breast cancer specimens (AACR2020, #1709). Thus, we investigated SOCS1-related immune-response under co-culture of TNBC and monocyte cell lines with or without paclitaxel exposure. Materials and Methods: MDA-MB-231, MDA-MB-468, RAW264.7 cell lines were used with co-culture system (Falcon® Cell Culture Inserts, Corning, NY, USA). SOCS1-expression vector and siSOCS1 were transfected into TNBC cell lines with polyethylenimine (PEI Max; Polysciences, Inc., Warrington, PA). RAW264.7 was activated with lipopolysaccaride (5ug/ml) and IFNγ (10ng/ml) for 2 days before co-culture. Relative cell viability of TNBC cell lines with vehicle control (DMSO) or paclitaxel exposure was measured with WST-8 (Cell Counting Kit-8; Dojindo, Japan) using TC20 Automated cell counter (Bio-Rad Laboratories, Inc., Japan) after 2 days’ co-culture of TNBC and RAW264.7 cells under several conditions of SOCS1 overexpression and/or RAW264.7 activation. Results: First, paclitaxel inhibited cell growth of MDA-MB-231 and MDA-MB-468 in a dose-dependent manner (at 1nM~100nM). Second, at paclitaxel exposure of 10 nM and 50 nM, relative cell viability of MDA-MB-468 decreased with co-culture of activated RAW264.7. The tendency was enhanced with SOCS1 overexpression in breast cancer cell lines. Similar results were observed in MDA-MB-231 cells. Discussions: SOCS1 is well known as a negative regulator of JAK-STAT pathway. SOCS1 is also related to suppression of T cell activation and modulation of M1 macrophage. At AACR2020, we reported that SOCS1 gene amplification in cancer tissues after neoadjuvant chemotherapy was relatively lower in 6 cases with pathologically partial or complete response than in 11 cases with no pathological response. In vitro, paclitaxel-toxicity in TNBC cells was augmented by activated monocyte (M1 macrophage) and more sensitized with SOCS1 overexpression in TNBC cells. These results suggest that proinflammatory cytokines from M1 macrophage influence cell viability of TNBC. Conclusion: SOCS1 is a promising molecular target to modulate immune-response in TNBC. Citation Format: Shigeru Imoto, Tomohiro Chiba, Hirohito Seki, Yoshiharu Ishizaka, Ai Tsuchiya, Tomoko Kitaoka. New targeted therapy on SOCS1-related immune-response in triple-negative breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5363.

Prognostic Values of CD8+, PARP, and EGFR on Overall Survival in Patients with Triple-Negative Breast Cancer.

This study aimed to investigate the associations of CD8+, PARP, and EGFR expressions with two-year survival in patients with triple-negative breast cancer (TNBC). A retrospective cohort study was conducted in a national cancer center. All patients aged 18 years diagnosed with TNBC (2013-2017) were included and followed for 24 months or until the patients were deceased. Kaplan-Meier survival function and Cox proportional hazard model were applied for the analyses. The study population was followed for 24 months (2,692 person-months, N = 126). At the end of the follow-up, 27 patients were deceased. The two-year mortality rate was 10 per 1,000 person-month. Kaplan-Meier graphs showed that after approximately one year of follow-up, poorer survival was seen in patients with low CD8+, positive PARP, and positive EGFR. The adjusted analysis found staging as the main predictor of overall survival in TNBC (HR = 7.20, 95% CI= 2.07 - 25.00). Patients with low CD8+, positive PARP, and positive EGFR expressions seem to be associated with poorer overall survival in TNBC. After approximately one year of follow-up, higher survival was observed in patients with high CD8+, negative PARP, and negative EGFR. Staging remains the main predictor of TNBC survival. Therefore, early detection and treatment of TNBC are essential to improve survival.