Triple-negative Breast Cancer Breast Cancer Research Articles

Ultrafast dynamic contrast-enhanced breast MRI with quantitative perfusion parameters in differentiating breast cancer: a study focusing on triple-negative and HER2 positive breast cancer.

In the realm of breast cancer diagnosis and treatment, accurately discerning molecular subtypes is of paramount importance, especially when aiming to avoid invasive tests. The updated guidelines for diagnosing and treating HER2 positive advanced breast cancer, as presented at the 2021 National Breast Cancer Conference and the Annual Meeting of the Chinese Society of Clinical Oncology, highlight the significance of this approach. A new generation of drug-antibody combinations has emerged, expanding the array of treatment options for HER2 positive advanced breast cancer and significantly improving patient survival rates. Triple-negative breast cancer (TNBC), on the other hand, may indicate survival outcomes following multi-agent adjuvant chemotherapy. DISCO is a more recent DCE MRI technique that has achieved high spatial and temporal resolution and minimized image artifacts in cases like malignant focal liver lesions, enhanced focal breast lesions, and intracranial aneurysms. To employ the method mentioned above to differentiate between triple-negative and non-triple-negative as well as HER2 positive and HER2 negative cancer lesions, and to assess the value of quantitative and semi-quantitative parameters in molecularly typing breast cancer. All participants were scanned with a 3.0-T MR scanner (GE SIGNA™ Premier) using a 16-channel phased-array body coil. Each participant underwent a DISCO DCE-MRI with a scan time of approximately 1 minute and 40 seconds. The ROIs were outlined with the GenIQ software, avoiding regions with blood vessels, susceptibility artifacts, hemorrhage, and necrosis. We evaluated four quantitative parameters (Ktrans, kep, ve, vp) and four semi-quantitative parameters (TTP, MAX Conc, AUC, MAX Slope). The carcinomas were segregated into respective subgroups (HER2+ vs HER2-, TNBC vs non-TNBC, HER2+ vs TNBC) and we compared the eight parameters across these groups. The AUC of the models was compared using DeLong's test as per the ROC analysis. We analyzed a total of 96 female patients, revealing significant differences in the semi-quantitative parameters such as TTP, MAX Conc, AUC, and MAX Slope among different groups. HER2-positive versus HER2-negative exhibited significant differences in quantitative parameters (Ktrans: 0.22 min-1 vs. 0.43 min-1, kep: 0.11 min-1 vs. 0.35 min-1, vp: 0.01 vs. 0.04, all P < 0.05). TNBC versus non-TNBC revealed statistical variations in quantitative parameters (Ktrans: 1.03 min-1 vs. 0.15 min-1, kep: 0.61 min-1 vs. 0.19 min-1, vp: 0.18 vs. 0.01, all P < 0.05). Additionally, HER2-positive compared to TNBC demonstrated significant differences in quantitative parameters (Ktrans: 0.22 min-1 vs. 1.03 min-1, kep: 0.11 min-1 vs. 0.61 min-1, vp: 0.01 vs. 0.18, all P < 0.05). As per ROC analysis, Ktrans, kep, vp, TTP, and MAX Conc effectively differentiated TNBC from non-TNBC, with TTP being the strongest determinant for TNBC. Furthermore, these parameters successfully distinguished between HER2 positive and HER2 negative, with kep being particularly effective in identifying HER2. Importantly, Ktrans, kep, vp, TTP, and MAX Conc were effective in discriminating HER2 positive from TNBC, with kep and TTP exhibiting notable efficacy in this context. Our study suggests that DISCO DCE-MRI derived parameters could serve as reliable quantitative biomarkers for differentiating between TNBC and HER2 positive breast cancer.

Metabolic shifts in lipid utilization and reciprocal interactions within the lung metastatic niche of triple-negative breast cancer revealed by spatial multi-omics

The Triple-Negative Breast Cancer (TNBC) subtype constitutes 15-20% of breast cancer cases and is associated with the poorest clinical outcomes. Distant metastasis, particularly to the lungs, is a major contributor to the high mortality rates in breast cancer patients. Despite this, there has been a lack of comprehensive insights into the heterogeneity of metastatic tumors and their surrounding ecosystem in the lungs. In this study, we utilized spatial RNA sequencing technology to investigate the heterogeneity of lung metastatic tumors and their microenvironment in two spontaneous lung metastatic mouse models. Our findings revealed an increase in metabolic-related genes within the cancer cells, with the hub gene Dlat (Dihydrolipoamide S-Acetyltransferase) showing a significant association with the development of lung metastatic tumors. Upregulation of Dlat led to the reprogramming of fatty acid utilization, markedly enhancing the bioenergetic capacity of cancer cells. This finding was corroborated by the increased dependence on fatty acid utilization in lung metastatic cancer cells, and inhibition of Dlat in breast cancer cells exhibited a reduced oxygen consumption rate. Consequently, inhibition of Dlat resulted in decreased survival capacity of breast cancer by reducing cancer stem cell properties and cell adhesion in the lung in vivo. The three cell components within the lung metastatic niche, including CD163+ macrophages, neutrophils, and endothelial cells, expressed elevated levels of ApoE, leading to the secretion of various protumorigenic molecules that promote cancer cell growth in the lung. These molecules include galectin-1, S100A10, S100A4, and S100A6. Collectively, our findings highlight the lipid metabolism reprogramming of cancer and components of the tumor microenvironment that support lung metastasis of TNBC breast cancer.

Efficacy and feasibility of neoadjuvant pembrolizumab plus chemotherapy for early-stage triple-negative and estrogen receptor low, HER2-negative breast cancer: a Japanese single-institution real-world study.

Neoadjuvant pembrolizumab plus chemotherapy and adjuvant pembrolizumab have been established as the optimal systemic therapies for patients with early stage triple-negative breast cancer (TNBC); however, their efficacy and feasibility in the Japanese population remain unexplored. This study included patients with early stage TNBC or low estrogen receptor (ER) positivity (1-9%) with human epidermal growth factor receptor type 2- (HER2-) negative breast cancer who received neoadjuvant pembrolizumab plus chemotherapy from October 2022 at Cancer Institute Hospital of Japanese Foundation for Cancer Research. Information regarding clinicopathological features, systemic therapy, treatment outcomes, and adverse events of patients who underwent surgery by February 2024 was retrospectively collected. Overall, 69 patients received neoadjuvant pembrolizumab plus carboplatin and paclitaxel therapy, and 46 underwent surgery by February 2024. The median age of the patients was 53.5years, and 80.4% and 19.6% had stage II and III disease, respectively. TNBC and ER-low HER2-negative breast cancer accounted for 82.6% and 17.4% cases, respectively. Overall pathological complete response rate was 56.5%, with 87.5% in patients with ER-low HER2-negative tumors. The completion rates for neoadjuvant pembrolizumab, chemotherapy, and pembrolizumab plus chemotherapy were 65.2%, 56.5%, and 52.2%, respectively. Furthermore, 80.4% and 15.2% of patients experienced grade 3 or higher treatment-related adverse events and immune-related adverse events, respectively, and 34% experienced unexpected hospitalization during neoadjuvant treatment. The efficacy and safety profiles of neoadjuvant pembrolizumab plus chemotherapy in the Japanese population are consistent with previous reports. This regimen may have therapeutic potential against ER-low HER2-negative tumors and TNBC.

Impact of delays in neoadjuvant chemotherapy initiation on pathologic complete response among patients with HER2-positive or triple negative breast cancer.

102 Background: Pathologic complete response (pCR) is used as a surrogate endpoint for overall survival (OS) in high-risk early-stage breast cancer (BC). pCR rates vary according to BC molecular subtype and have the highest association with OS in triple negative BC (TNBC) and HER2-positive (HER2+) BC. In these subgroups, neoadjuvant chemotherapy (NACT) is often the standard of care. We evaluated the association of delays in NACT initiation (NACTI) with pCR. Methods: We conducted a retrospective cohort study using the National Cancer Database. Eligibility included age ≥18 years, diagnosis cT2+ or lymph node positive HER2+ or TNBC between 1/1/2010 – 12/31/2020, who were treated with NACT within 180 days of BC diagnosis. Time to chemotherapy (TTC) was recorded in days. Patients were categorized by receptor status. We used AJCC 7 th and 8 th edition T and N staging to define pCR (pT0 or pTis and pN0 or pN0I-). Delay was defined as TTC &gt; 60 days. Multivariable logistic regression, adjusted for demographic, socioeconomic and tumor characteristics, was used to calculate odds of pCR associated with delays. A sensitivity analysis defining delay &gt;30 and &gt;90 days was also conducted. Results: We identified 105,352 eligible patients, 73% were White, 19% were Black, 3% were Asian, and 4% were Other/Unknown. Median age at diagnosis was 52 years (range 18-90), median TTC was 32 days (range 0-180). There were 56,868 patients with HER2+ BC and 48,484 with TNBC; 9% of patients were delayed &gt; 60 days in each group. Among all HER2+ patients, 39.1% achieved a pCR: 35.0% with delay compared to 39.5% without delay. Among TNBC patients, 30% achieved a pCR: 25% with delay compared to 31% without delay (p &lt; 0.0001 for all). In multivariable analysis, patients with HER2+ disease (OR 0.85, 95%CI 0.79-0.92) and TNBC (OR 0.80, 95%CI 0.73-0.87) were less likely to achieve pCR if delayed &gt; 60 days. In a sensitivity analysis, delay &gt; 30 days was associated with lower likelihood of achieving pCR for all and delay &gt; 90 days was associated with lower likelihood for TNBC (Table). Conclusions: Delays in NACTI &gt;60 days among patients with HER2+ and TNBC BC was an independent predictor of not achieving pCR. Given the known association between socioeconomic factors and delays to initiation of treatment, interventions aimed at reducing delays may reduce disparities in BC outcomes. Future studies to identify causes of delays and the downstream impact are needed to ultimately develop interventions that mitigate these effects among patients with HER2+ or TNBC, where pCR rates are associated with OS. Association of pCR in patients who experience NACTI delay using multivariable logistic regression* n(complete case) = 77,690. Subgroup &gt;30-day Delay in NACTIOR (95% CI) &gt;60-day Delay in NACTIOR (95% CI) &gt;90-day Delay in NACTIOR (95% CI) HER2+n =41,672 0.91 (0.87-0.95) 0.85 (0.79-0.92) 0.93 (0.80-1.07) TNBCn = 36,018 0.87 (0.83-0.92) 0.80 (0.73-0.87) 0.78 (0.65-0.92) *Adjusted for demographic, socioeconomic and tumor characteristics.

Canadian Expert Recommendations on Safety Overview and Toxicity Management Strategies for Sacituzumab Govitecan Based on Use in Metastatic Triple-Negative Breast Cancer.

Sacituzumab Govitecan (SG) is an antibody-drug conjugate (ADC) comprised of an anti-Trop-2 IgG1 molecule conjugated to SN-38, the active metabolite of irinotecan, via a pH-sensitive hydrolysable linker. As a result of recent Canadian funding for SG in advanced hormone receptor (HR)-positive breast cancer and triple-negative breast cancer (TNBC), experience with using SG and managing adverse events (AEs) has grown. This review presents a summary of evidence and adverse event recommendations derived from Canadian experience, with SG use in metastatic TNBC for extrapolation and guidance in all indicated settings. SG is dosed at 10 mg/kg on day 1 and day 8 of a 21-day cycle. Compared to treatment of physicians' choice (TPC) the phase III ASCENT and TROPiCS-02 studies demonstrated favorable survival data in unresectable locally advanced or metastatic TNBC and HR-positive HER2 negative metastatic breast cancer, respectively. The most common AEs were neutropenia, diarrhea, nausea, fatigue, alopecia, and anemia. This review outlines AE management recommendations for SG based on clinical trial protocols and Canadian guidelines, incorporating treatment delay, dose reductions, and the use of prophylactic and supportive medications.

FABP4-mediated lipid metabolism promotes TNBC progression and breast cancer stem cell activity

Metabolic remodeling is a pivotal feature of cancer, with cancer stem cells frequently showcasing distinctive metabolic behaviors. Nonetheless, understanding the metabolic intricacies of triple-negative breast cancer (TNBC) and breast cancer stem cells (BCSCs) has remained elusive. In this study, we meticulously characterized the metabolic profiles of TNBC and BCSCs and delved into their potential implications for TNBC treatment. Our findings illuminated the robust lipid metabolism activity within TNBC tumors, especially in BCSCs. Furthermore, we discovered that Fabp4, through its mediation of fatty acid uptake, plays a crucial role in regulating TNBC lipid metabolism. Knocking down Fabp4 or inhibiting its activity significantly suppressed TNBC tumor progression in both the MMTV-Wnt1 spontaneous TNBC model and the TNBC patient-derived xenograft model. Mechanistically, Fabp4's influence on TNBC tumor progression was linked to its regulation of mitochondrial stability, the CPT1-mediated fatty acid oxidation process, and ROS production. Notably, in a high-fat diet model, Fabp4 deficiency proved to be a substantial inhibitor of obesity-accelerated TNBC progression. Collectively, these findings shed light on the unique metabolic patterns of TNBC and BCSCs, underscore the biological significance of Fabp4-mediated fatty acid metabolism in governing TNBC progression, and offer a solid theoretical foundation for considering metabolic interventions in breast cancer treatment. SignificanceTriple-negative breast cancer progression and breast cancer stem cell activity can be restricted by targeting a critical regulator of lipid responses, FABP4.

Opportunities and Challenges in the Development of Antibody-Drug Conjugate for Triple-Negative Breast Cancer: The Diverse Choices and Changing Needs.

Triple-negative breast cancer (TNBC) is a highly heterogeneous breast cancer subtype, which is also characterized by the aggressive phenotype, high recurrence rate, and poor prognosis. Antibody-drug conjugate (ADC) is a monoclonal antibody with a cytotoxic payload connected by a linker. ADC is gaining more and more attention as a targeted anti-cancer agent. Clinical studies of emerging ADC drugs such as sacituzumab govitecan and trastuzumab deruxtecan in patients with metastatic breast cancer (including TNBC) are progressing rapidly. In view of its excellent clinical efficacy and good tolerability, Sacituzumab govitecan gained accelerated approval by the FDA for the treatment of advanced metastatic TNBC in 2020. This review discusses the treatment status and challenges in TNBC, with an emphasis on the current status of ADC development and clinical trials in TNBC and metastatic breast cancer. We also summarize the clinical experience and future exploration directions of ADC development for TNBC patients.

A phase 1 study of liposomal irinotecan in patients with advanced breast cancer.

1080 Background: Liposomal irinotecan (HE072) is a liposomal formulation that encapsulates irinotecan in a lipid bilayer vesicle, and as a generic drug, had been approved in China, recently, in patients with pancreatic cancer after gemcitabine treatment. Advanced triple negative breast cancer (TNBC) has very poor prognosis and limited treatment choices. Here we present results of breast cancer treated with HE072 in patients with highly pre-treated metastatic TNBC and HER2 negative breast cancer brain metastasis (BCBM). Methods: HE072-CSP-002 was a phase 1 study, consisting of two parts, dose escalation and expansion part (part 1) and expansion cohort part (part 2). In part 1, standard 3+3 design was used to investigate up to three dose levels of HE072 (50 mg/m2, 70 mg/m2 and 90 mg/m2), up to 6-9 additional subjects may be enrolled for dose expansion. In part 2, patients were enrolled in two cohorts (TNBC cohort and BCBM cohort), and received HE072 70 mg/m2 every two weeks (Q2W). The primary endpoints were the maximum tolerated dose (MTD) and recommended phase 2 dose (RP2D), and the incidence and severity of treatment emergent adverse events (TEAEs). Secondary endpoints included progression free survival (PFS), objective response rate (ORR), overall survival (OS). Results: As of June 5th, 2023, 119 patients were enrolled, including 101 patients with TNBC and 18 patients with HER2 negative BCBM (part 1: n=27; part 2: n=92). In the part 1, one dose-limiting toxicity (grade 3 nausea and grade 3 vomiting) was observed at 70 mg/m2 dose level, and MTD was not reached. A total of 115 patients (96.6%) had at least one TEAEs of any grade, and 55 patients (46.2%) had ≥grade 3 TEAEs. The most common ≥grade 3 TEAEs related to HE072 included neutropenia (21.0%), leukopenia (18.5%), diarrhea (10.1%), anemia (9.2%) and hypokalemia (8.4%). Eighty-three (82.2%) of the 101 patients with TNBC were evaluable for response. After a median follow-up of 10.1 months (range 8.8-10.8), 22 patients (26.5%, 95%CI 17.4-37.3) achieved overall response, which were all partial response and 58 patients (69.9%, 95%CI 58.8-79.5) achieved disease control. The median PFS and OS were 4.8 months (95%CI 3.9-5.8) and 14.1 months (95%CI 11.2-not reached), respectively. 12(66.7%) of the 18 patients with HER2 negative BCBM were evaluable for response. 1 patient (8.3%, 95%CI 0.2, 38.5) achieved overall response, which is partial response and 8 patients (66.7%, 95%CI 34.9, 90.1) achieved disease control. The median PFS was 5.6 months (95%CI 1.4~ not reached), 12-month OS rate was 55.5%. Conclusions: HE072 exhibited excellent antitumor activity in heavily pre-treated patients with TNBC and HER2 negative BCBM with acceptable safety profiles. 70 mg/m2 Q2W was determined as the RP2D. Further clinical trials are under plan. Clinical trial information: NCT04728035 .

Effects of Garlic on Breast Tumor Cells with a Triple Negative Phenotype: Peculiar Subtype-Dependent Down-Modulation of Akt Signaling.

Breast cancer includes tumor subgroups with morphological, molecular, and clinical differences. Intrinsic heterogeneity especially characterizes breast tumors with a triple negative phenotype, often leading to the failure of even the most advanced therapeutic strategies. To improve breast cancer treatment, the use of natural agents to integrate conventional therapies is the subject of ever-increasing attention. In this context, garlic (Allium sativum) shows anti-cancerous potential, interfering with the proliferation, motility, and malignant progression of both non-invasive and invasive breast tumor cells. As heterogeneity could be at the basis of variable effects, the main objective of our study was to evaluate the anti-tumoral activity of a garlic extract in breast cancer cells with a triple negative phenotype. Established triple negative breast cancer (TNBC) cell lines from patient-derived xenografts (PDXs) were used, revealing subtype-dependent effects on morphology, cell cycle, and invasive potential, correlated with the peculiar down-modulation of Akt signaling, a crucial regulator in solid tumors. Our results first demonstrate that the effects of garlic on TNBC breast cancer are not unique and suggest that only more precise knowledge of the mechanisms activated by this natural compound in each tumor will allow for the inclusion of garlic in personalized therapeutic approaches to breast cancer.

Abstract PO3-26-10: Small molecule inhibitor of PELP1 exhibit cytotoxic effects on breast cancer cells by blocking ribosome biogenesis

Abstract Introduction: Breast cancer (BC) is the second-leading cause of cancer-related deaths in women. Despite responsive to endocrine therapy, a sizeable portion of estrogen receptor positive (ER+) BC goes on to develop therapy-resistant breast cancer (TR-BC). Furthermore, triple-negative breast cancer (TNBC) has a more aggressive clinical course with fewer targeted therapeutic options. The development of more effective therapies for TR-BC or TNBC represent an unmet need. Excessive ribosome biogenesis has recently been linked to BC progression, and resistance to therapy. Oncogene PELP1, which is required for ribosome biogenesis, is frequently dysregulated in BC and serves as a prognostic factor for poor BC survival and therapy resistance. We recently identified SMIP34 as a PELP1 small molecule inhibitor of its kind and it is effective against both TR-BC and TNBC. The objective of this study is to determine the mechanisms by which SMIP34 exhibit cytotoxic effects on BC cells. Methods: We have used multiple ER+, therapy resistant and TNBC models in cell viability, and apoptosis assays. Modelling studies were done based on Cryo-EM structure of the WDR18/PELP1 Rix1 complex (PDB code 7UWF). Biochemical assays include immune precipitation, reporter assays, GST pulldown, and Western Blotting. SMIP34 effect on protein synthesis was measured by using Western blot of puromycin treated total lysates for puromycinylated protein content. SMIP34 effect on protein synthesis assessed using Cayman’s Protein Synthesis Assay Kit. Ribosome biogenesis in SMIP34 treated cells was monitored using confocal microscopy using rpS6 antibody. Results: In in vitro cell based assays, SMIP34 was highly effective in reducing the cell viability, reducing colony formation and inducing apoptosis of ER+, endocrine therapy resistant, and TNBC model cells. PELP1 homodimer has recently been predicated to act as the core of the WDR18/PELP1 assembly. Our biochemical assay results suggest that SMIP34 binds to the same region involved in the PELP1 homodimerization and disrupts the formation of PELP1 homodimer and subsequently blocks the formation of WDR18/PELP1 Rix1 complex. Modeling studies predicted that altering the conformation of PELP1 aa 696-720 loop by SMIP34 binding may influence the conformation of the following C-terminal region, which may disturb the interaction of other PELP1 partners such as SENP3 and TEX10. Accordingly, the results from immunoprecipitation experiments demonstrated decreased association of Rix1 complex proteins WDR18, TEX10, and SENP3 with PELP1 under conditions of SMIP34 treatment. Further, Western blotting analysis confirmed that SMIP34 treatment decreased levels of PELP1 and its complex proteins, such as WDR18, TEX10, LAS1L, and SENP3. SMIP34 significantly reduced ribosomal biogenesis in a dose dependent manner. Additionally, puromycin labelling experiments confirmed a dose dependent decrease in new protein synthesis upon SMIP34 administration. Data from the DepMap database analysis revealed that PELP1 is required for cancer cell survival. Additionally, analysis of TCGA breast cancer datasets revealed that PELP1 expression is positively correlated with WDR18, TEX10, LAS1L, and SENP3. In in vivo xenograft assays and ex vivo explant assays using tumor tissue, SMIP34 strongly inhibited the growth of ER+, endocrine treatment resistant, and TNBC model cells. Conclusion: These findings provide solid evidence that the Rix1 complex, which is required for ribosomes production, is disturbed by SMIP34 binding to PELP1. SMIP34 represents a new therapeutic for the treatment of both ER+ and TNBC breast cancer. Supported by VA grant 1 I01 BX004545-01A1. Citation Format: Xue Yang, Khaled Mohamed Nassar, Uday Pratap, Rahul Gopalam, Behnam Ebrahimi, Durga Meenakshi Panneerdoss, Xiaonan Li, Yaxia Yuan, Daohong Zhou, Gangadhara R. Sareddy, Rajeshwar R. Tekmal, Manjeet Rao, Suryavathi Viswanadhapalli, Ratna Vadlamudi. Small molecule inhibitor of PELP1 exhibit cytotoxic effects on breast cancer cells by blocking ribosome biogenesis [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 PO3-26-10.

Abstract PO5-06-01: Loss of hormone receptor expression in breast cancer is associated with increased brain tropism and accelerated progression of leptomeningeal disease

Abstract The four breast cancer subtypes—luminal A, luminal B, HER2-overexpressing, and triple-negative breast cancer (TNBC) – are classified based on gene expression profiles of hormone receptors (HRs) (estrogen receptor (ER) and progesterone receptor (PR)) and human epidermal growth factor receptor 2 (HER2/ERBB2). Negative hormone receptor status is known to be associated with more aggressive breast cancer. Compared to other breast cancer subtypes, the HR-negative TNBC and HER2-overexpressing subtypes are characterized by high rates of recurrence and a notable increase in brain metastases and in particular, leptomeningeal disease (LMD). LMD – the most aggressive form of central nervous system (CNS) metastasis, in which cancer cells infiltrate leptomeninges of the brain and spine – carries a dismal prognosis due to a rapid progression, poor detection, and no effective treatment. Several studies that investigated the link between HR status and LMD suggest that HR-negative breast cancers have a shorter time to LMD diagnosis. This shortened timeline is consistent with higher migratory capabilities reported for TNBC and HER2 breast cancer cells. However, as it is known that breast cancers exhibit subtype-specific metastatic tropism (i.e., luminal subtypes tend to metastasize to bone and liver, while TNBCs metastasize to the CNS), the longer time between primary breast cancer diagnosis and LMD diagnosis for HR-positive breast cancers may also reflect a longer metastatic route that first includes a non-CNS location. In this study, we performed a retrospective analysis on 141 breast cancer patients with LMD treated at Stanford Hospital between 2008-2020. The Stanford LMD cohort was analyzed using linear regression analysis, Cox regression analysis, and Chi-squared analysis. HR status was recorded (when available) for local recurrences and distant metastases, and was included in our regression models as a time-dependent HR covariate. We tested if: (1) HR-negative breast cancers had shorter time between primary and LMD diagnosis as well as worse survival after LMD diagnosis versus HR-positive breast cancers, and if (2) HR loss (i.e., HR status changing from positive to negative) increased likelihood of the metastasis to CNS. In agreement with published studies, the Stanford LMD cohort showed that HR-negative cancers had shorter time to development of LMD (p = 0.0004 for ER, p = 0.0001 for PR) and increased mortality following LMD (p = 0.010 for ER, p = 0.009 for PR). We found that HR-negative status at primary breast cancer diagnosis increased risk of first metastasis to CNS versus non-CNS locations (p = 0.021 for ER, p = 0.043 for PR). HR status switch (also known as hormone discordance) between primary diagnosis and metastasis occurred in 15% of patients in Stanford cohort, consistent with other studies. Importantly, accounting for HR status switch strengthened the association between HR-negative status and the risk of CNS metastasis [Hazard Ratio = 2.506 (1.395 - 4.500) for “baseline ER status” versus Hazard Ratio = 3.509 (1.890 - 6.515) for “time-dependent ER status”, Hazard Ratio = 2.420 (1.310 - 4.471) for “baseline PR status” versus Hazard Ratio = 3.407 (1.815 - 6.395) for “time-dependent PR status”]. In conclusion, HR-negative status was associated with shorter time to development of LMD, higher CNS tropism, and shorter survival following LMD diagnosis. Taking into consideration hormone discordance between the primary tumor and metastatic sites strengthened this association. Our results suggest a potential value in testing HR status at all recurrences and advanced CNS monitoring following HR loss. Citation Format: Sophia Pribus, Maxine C. Umeh-Garcia, Bo Gu, Bryanna Godfrey, Summer Han, Sophia Chernikova, Melanie Hayden Gephart. Loss of hormone receptor expression in breast cancer is associated with increased brain tropism and accelerated progression of leptomeningeal disease [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 PO5-06-01.

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.

Prenatal BRCA1 epimutations contribute significantly to triple-negative breast cancer development

BackgroundNormal cell BRCA1 epimutations have been associated with increased risk of triple-negative breast cancer (TNBC). However, the fraction of TNBCs that may have BRCA1 epimutations as their underlying cause is unknown. Neither are the time of occurrence and the potential inheritance patterns of BRCA1 epimutations established.MethodsTo address these questions, we analyzed BRCA1 methylation status in breast cancer tissue and matched white blood cells (WBC) from 408 patients with 411 primary breast cancers, including 66 TNBCs, applying a highly sensitive sequencing assay, allowing allele-resolved methylation assessment. Furthermore, to assess the time of origin and the characteristics of normal cell BRCA1 methylation, we analyzed umbilical cord blood of 1260 newborn girls and 200 newborn boys. Finally, we assessed BRCA1 methylation status among 575 mothers and 531 fathers of girls with (n = 102) and without (n = 473) BRCA1 methylation.ResultsWe found concordant tumor and mosaic WBC BRCA1 epimutations in 10 out of 66 patients with TNBC and in four out of six patients with estrogen receptor (ER)-low expression (< 10%) tumors (combined: 14 out of 72; 19.4%; 95% CI 11.1–30.5). In contrast, we found concordant WBC and tumor methylation in only three out of 220 patients with 221 ER ≥ 10% tumors and zero out of 114 patients with 116 HER2-positive tumors. Intraindividually, BRCA1 epimutations affected the same allele in normal and tumor cells. Assessing BRCA1 methylation in umbilical WBCs from girls, we found mosaic, predominantly monoallelic BRCA1 epimutations, with qualitative features similar to those in adults, in 113/1260 (9.0%) of individuals, but no correlation to BRCA1 methylation status either in mothers or fathers. A significantly lower fraction of newborn boys carried BRCA1 methylation (9/200; 4.5%) as compared to girls (p = 0.038). Similarly, WBC BRCA1 methylation was found less common among fathers (16/531; 3.0%), as compared to mothers (46/575; 8.0%; p = 0.0003).ConclusionsOur findings suggest prenatal BRCA1 epimutations might be the underlying cause of around 20% of TNBC and low-ER expression breast cancers. Such constitutional mosaic BRCA1 methylation likely arise through gender-related mechanisms in utero, independent of Mendelian inheritance.

RL2 Enhances the Elimination of Breast Cancer Cells by Doxorubicin.

RL2 (recombinant lactaptin 2), a recombinant analogon of the human milk protein Κ-Casein, induces mitophagy and cell death in breast carcinoma cells. Furthermore, RL2 was shown to enhance extrinsic apoptosis upon long-term treatment while inhibiting it upon short-term stimulation. However, the effects of RL2 on the action of chemotherapeutic drugs that induce the intrinsic apoptotic pathway have not been investigated to date. Here, we examined the effects of RL2 on the doxorubicin (DXR)-induced cell death in breast cancer cells with three different backgrounds. In particular, we used BT549 and MDA-MB-231 triple-negative breast cancer (TNBC) cells, T47D estrogen receptor alpha (ERα) positive cells, and SKBR3 human epidermal growth factor receptor 2 (HER2) positive cells. BT549, MDA-MB-231, and T47D cells showed a severe loss of cell viability upon RL2 treatment, accompanied by the induction of mitophagy. Furthermore, BT549, MDA-MB-231, and T47D cells could be sensitized towards DXR treatment with RL2, as evidenced by loss of cell viability. In contrast, SKBR3 cells showed almost no RL2-induced loss of cell viability when treated with RL2 alone, and RL2 did not sensitize SKBR3 cells towards DXR-mediated loss of cell viability. Bioinformatic analysis of gene expression showed an enrichment of genes controlling metabolism in SKBR3 cells compared to the other cell lines. This suggests that the metabolic status of the cells is important for their sensitivity to RL2. Taken together, we have shown that RL2 can enhance the intrinsic apoptotic pathway in TNBC and ERα-positive breast cancer cells, paving the way for the development of novel therapeutic strategies.

Abstract LB_C04: Novel orally bioavailable macrocycles that target cyclin A and B elicit antitumor activity in breast cancer patient-derived xenograft models

Abstract Background: Cyclin/cyclin-dependent kinase (CDK) complexes regulate the activity of RB1 and E2F to drive cell cycle progression while ensuring fidelity of DNA replication. The interaction between cyclins and a critical subset of their substrates, including RB1 and E2F, is mediated by a conserved short linear RxL motif. RxL peptides have been shown to inhibit substrate phosphorylation by CDK2/cyclin A (AACR 2022 poster #5379). Previously, we have shown that macrocycles that selectively inhibit RxL-mediated binding to cyclins A and B (RxL inhibitors) lead to growth inhibitory activity in multiple cancer cell lines, and result in tumor regression in small cell lung cancer (SCLC) and ovarian cancer xenograft models (AACR 2023 poster #1560). Here, we test the antitumor activity of CID-016 in patient-derived xenograft (PDX) models from breast cancer. Methods: Bioinformatic analyses using RNA sequencing (RNAseq) and whole exome sequencing (WES) data from 39 breast cancer cell lines was employed to identify biomarker profiles that associate with sensitivity to CID-016. The antiproliferative activity of CID-016 was assessed by GI50 after 4-8 days of treatment. Hallmark pathway scores were calculated by Gene Set Variation Analysis (GSVA) method using MSigDb Hallmark collection from cell lines and existing PDX models. Based on the calculated hallmark pathway score, triple negative breast cancer (TNBC) PDX models were selected to test the anti-tumor activity of CID-016. In vivo, NMRI-Foxn1nu/nu mice were implanted with tumor fragments in the lower flank and treated with vehicle or CID-016 oral formulation of 50-100 mg/kg BID or 100 mg/kg QD, respectively for at least 28 days. Tumor volume and body weight were measured biweekly. Pharmacodynamic (PD) analyses will be conducted after treatment with CID-016. Results: Treatment of the breast cancer cell line panel with CID-016 demonstrated greater potency by GI50 in TNBC compared to other breast cancer cell lines (p=0.009). Gene expression levels of CCNB1, CCNA2, CCNE1 as well as target hallmark scores for “E2F targets”, “G2M checkpoint” and “Mitotic spindle” were significantly higher in TNBC vs other breast cancer cell lines. Oral treatment with CID-016 resulted in tumor regression in at least one triple-negative breast cancer PDX model and was well tolerated with no significant body weight changes. In vivo PD analyses will be assessed after 5 days of treatment with CID-016. Conclusions: The selective cyclin A/B RxL inhibitor CID-016 exhibits potent antitumor activity in TNBC preclinical models, consistent with the proposed mechanism of RB1/E2F pathway dysregulation. Given their compelling characteristics, orally bioavailable RxL inhibitors are advancing as the only first-in-class orally bioavailable dual inhibitors of cyclins A and B into clinical development. Citation Format: Mariana Paes Dias, Li-Fen Liu, Bernard Levin, Cristina Molina, Marta Guzmán, Olga Rodríguez, Evelyn W. Wang, Violeta Serra. Novel orally bioavailable macrocycles that target cyclin A and B elicit antitumor activity in breast cancer patient-derived xenograft models [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2023 Oct 11-15; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2023;22(12 Suppl):Abstract nr LB_C04.

Abstract PR014: Racialized economic polarization effects on postoperative complications in patients with triple negative breast cancer

Abstract INTRODUCTION The physical separation of residential housing based on race and income, otherwise known as racialized economic residential segregation, has been associated with more aggressive tumor pathology and higher mortality in patients with breast cancer. The purpose of this study is to evaluate the impact of racialized economic segregation on post-operative complications (POC) in surgical patients with triple negative breast cancer (TNBC). METHODS Women aged 18+ diagnosed with stage I-III TNBC between 1/1/12-12/31/20 who underwent surgery were identified in the cancer registry and electronic medical record at a comprehensive cancer center. Racial (ICE-race) and racialized economic (ICE-race-income) polarization were operationalized using the Index of Concentration at the Extremes (ICE) at the census tract level. Metrics were divided into quartiles where higher quartiles represented greater polarization. Postoperative complications (POC) included technical, infectious, respiratory, urinary, and cardiovascular complications within 30 days of surgery. Crude and adjusted logistic regression generalized estimating equations (GEE) assessed the association between greater racial (ICE-race) and racialized economic (ICE-race-income) segregation as exposures and POC as the outcome, while accounting for clustering effects. Models were adjusted for age, race, ethnicity, health insurance, marital status, history of alcohol and smoking use, molecular subtype, clinical stage, receipt of chemotherapy, breast and axillary surgery type, and surgical reconstruction. RESULTS 626 patients were included in the study, of whom 509 (81.4%) identified as White, 97 (15.5%) Black, and 20 (3.2%) other. Median age was 59 (IQR 49.0, 67.0) years. Average overall frequency of POC was 8.2%, with increased odds in patients living in neighborhoods with greater racial segregation (ICE-race: Q1 4.0% vs. Q4 12.3%, P=0.02) and racialized economic segregation (ICE-race-income: Q1 3.2% vs. Q4 13.4%, P=0.001). Patients with TNBC living in neighborhoods with greater racialized economic segregation had a 2.52 (95% CI: 1.22 – 5.22) adjusted odds of POC compared to patients residing in less segregated neighborhoods. A one-quartile increase in racial segregation was associated with 41% increased odds of POC (aOR 1.41, 95% CI: 1.00 – 1.98). Similarly, a one-quartile increase in racialized economic polarization was associated with 45% increased odds of POC (aOR 1.45, 95% CI: 1.05 - 2.01). CONCLUSIONS Patients with TNBC breast cancer residing in areas with greater racial segregation or racialized economic segregation are more likely to experience postoperative complications than their counterparts in less segregated areas. Future studies need to examine the mechanistic pathways between neighborhood contextual factors and poor postoperative outcomes. Citation Format: J.C. Chen, Mohamed I. Elsaid, Jesse J. Plascak, Daniel G. Stover, William E. Carson, Timothy M. Pawlik, Samilia Obeng-Gyasi. Racialized economic polarization effects on postoperative complications in patients with triple negative breast cancer [abstract]. In: Proceedings of the 16th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2023 Sep 29-Oct 2;Orlando, FL. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2023;32(12 Suppl):Abstract nr PR014.

The Synergistic Cytotoxic Effect of Pentagamavunon-1 (PGV-1) and Curcumin Correlates with the Cell Cycle Arrest to Induce Mitotic Catastrophe in 4T1 and T47D Breast Cancer Cells

BACKGROUND: The anti-cancer properties of pentagamavunon-1 (PGV-1) and curcumin have been documented. This study aimed to evaluate the cytotoxic effect of this combination on breast cancer cell growth using 4T1 and T47D cells, representing triple-negative breast cancer (TNBC) and non-TNBC, respectively.METHODS: Cytotoxic assay was evaluated using MTT reagent for single and combination treatment of PGV-1 and curcumin in 4T1 and T47D cells. Cell cycle analysis was examined through flowcytometry with propidium iodide dye. May Grünwald-Giemsa staining was also performed to analyze the mitotic catastropheRESULTS: PGV-1 and curcumin alone had significant cytotoxic effects against two breast cancer cell lines, with IC50 values of 4 μM and 40 μM for 4T1 and 2 μM and 20 μM for T47D, respectively. Both compounds showed high selectivity for the 4T1 and T47D cells (selectivity index &gt;3). In addition, when PGV-1 and curcumin were combined, a synergistic effect was observed in both cell types with a combination index of &lt;0.7. This combination results in cell cycle arrest in the G2/M phase, increased cell accumulation in the sub-G1 phase, and a synergistic increase in mitotic catastrophe.CONCLUSION: Combined intervention of PGV-1 and curcumin on TNBC and non-TNBC breast cancer cells substantially augments cell cycle arrest in the G2/M and sub-G1 phases, coupled with the occurrence of mitotic catastrophe. In summary, the results suggest that PGV-1 coupled with curcumin holds promise as an effective approach to addressing breast cancer and warrants further investigation.KEYWORDS: 4T1 cells, T47D cells, breast cancer, curcumin, mitotic catastrophe, PGV-1

Targeting VEGF/Neuropilin-2 as a Novel Approach to Induce Radiosensitivity in Triple Negative Breast Cancer

Triple-negative breast cancer (TNBC) is an aggressive phenotype with patients having more limited survival compared with other breast cancer subtypes. The high rate of locoregional/distant recurrence after primary management implies that additional treatment is necessary to optimize the sensitivity of TNBC tumors to therapy including radiation. Our lab studies the role of VEGF/Neuropilin-2 (NRP2) in mediating cancer stem cell properties such as self-renewal and therapy resistance. We sought to identify a new therapeutic approach that can induce radiosensitization in TNBC. Cell viability in response to radiotherapy in patient-derived organoids (PDO) and xenografts (PDX) was determined using CellTiter-Glo. The VEGF/NRP2 pathway was disrupted in human BT549 and murine 4T1 models using RNA interference and a function blocking antibody (aNRP2-10) provided by aTyr Pharma. Nitrite levels, a surrogate marker for NOS2 activity, were measured using Measure-IT Nitrite Assay Kit. H2DCFDA was used to measure intracellular reactive oxygen species (ROS). Clonogenic survival assays were used to calculate radiosensitivity enhancement ratios (rER) in TNBC cell lines. For our in vivo models, 4T1 xenografts were given antibody treatment every 48 hours starting a day prior to 10Gy irradiation. We identified a novel radioresistant population expressing high levels of NRP2 and NOS2 and observed that NOS2 expression was dependent on VEGF/NRP2 via Gli1 transcription. Interestingly, reducing NRP2 expression increased radiation-induced ROS because of reduced NOS2/NO levels. The downstream consequence of higher NOS2/NO was increased Nrf2 activation via KEAP1 S-nitrosylation; thus, inducing expression of antioxidant response elements. TNBC cells were radiosensitized by knocking down NRP2 (rER 1.19 - 1.34). We saw similar results when using aNRP2-10 vs IgG (rER 1.30 - 1.37). Ectopic expression of NOS2 and constitutively active Nrf2 rescued the radioresistance phenotype in the NRP2 knock-down cells (rER 0.73 - 0.82). Consistent with the cell line data, the clinically relevant models (PDOs and PDXs) had a synergistic reduction in cell viability in response to aNRP2-10 prior to radiotherapy. We also observed a significant reduction in tumor volume and increase in necrosis in vivo in response to VEGF/NRP2 inhibition during radiotherapy. Inhibiting VEGF/NRP2 induces radiosensitization of TNBC by decreasing NOS2/NO levels and, consequently, Nrf2-mediated antioxidant gene expression. The role of Gli1 as a transcription factor for NOS2 is a novel finding that provides an unexpected link between VEGF/NRP2 and redox homeostasis in response to radiation. Current Nrf2 inhibitors are non-specific and have high toxicity; thus, making VEGF/NRP2 inhibition more favorable. Our data provide a novel therapeutic strategy for targeting TNBC breast cancer.

Glutaminase (GLS1) gene expression in primary breast cancer.

Tumor growth is mediated in part by glutamine, and glutaminase is an enzyme necessary for glutamine catabolism. We studied glutaminase (GLS1) gene expression in primary breast cancer to determine correlations with clinical and tumor characteristics, and gene associations in publicly available databases. A better understanding of glutaminase gene expression may help guide further exploration of glutaminase inhibitors in breast cancer. GLS1 mRNA levels were evaluated in The Cancer Genome Atlas (n = 817) and METABRIC (n = 1992) datasets. Associations between GLS1 and tumor subtype (ANOVA followed by post-hoc Tukey test for pairwise comparisons) and selected genes involved in the pathogenesis of breast cancer (Pearson's correlations) were determined in both datasets. In METABRIC, associations with overall survival (Cox proportional hazard model) were determined. For all analyses, p < 0.05 was the threshold for statistical significance. GLS1 expression was significantly higher in triple negative breast cancer (TNBC) than hormone receptor (HR) +/HER2- and HER2+ breast cancer (p < 0.001) and basal versus luminal A, luminal B, and HER2 enriched breast cancer (p < 0.001) in both datasets. In METABRIC, higher GLS1 expression was associated with improved overall survival (HR 0.91, 95% CI: 0.85-0.97, p = 0.005) and this association remained significant in the TNBC subset (HR 0.83, 95% CI: 0.71-0.98, p = 0.032). GLS1 had significant positive gene correlations with immune, proliferative, and basal genes, and inverse correlations with luminal genes and genes involved in metabolism. GLS1 expression is highest in TNBC and basal breast cancer, supporting ongoing clinical investigation of GLS1 inhibition in TNBC. GLS1 may have prognostic implications but further research is needed to validate this finding. GLS1 had significant positive gene correlations with immune genes, which may have implications for potential combinations of glutaminase inhibition and immunotherapy.

Hsa-miR-497-3p impedes the proliferation and invasion of triple-negative breast cancer cells by controlling epithelial-mesenchymal transition through ZEB1 targeting.

This study aimed to examine the hsa-miR-497-3p effect and mechanism on the behavior of triple-negative breast cancer (TNBC) cells. We evaluated the expression of Hsa-miR-497-3p in tissue samples obtained from patients diagnosed with TNBC or luminal breast cancer (BrCa), utilizing the quantitative fluorescence polymerase chain reaction (PCR) method. We transfected hsa-miR-497-3p mimics and NC into MDA-MB-231 cells, whilehsa-miR-497-3p inhibitor and NC into TNBC cells, respectively. To examine the impact of hsa-miR-497-3p expression level on TNBC cell proliferation, invasion, and migration, we employed MTT, clone formation, Transwell, and wound healing assays. We utilized both q-PCR and western blot to validate the role of hsa-miR-497-3p in the epithelial-mesenchymal transition (EMT) of TNBC cells. To confirm the targeting relationship between hsa-miR-497-3p and ZEB1, we performed luciferase assays, q-PCR, and western blot analysis. We found that the hsa-miR-497-3p expression was down-regulated in both TNBC tissues and cell lines in comparison to luminal BrCa tissues and cell lines. Furthermore, hsa-miR-497-3p overexpression hindered the cell function of TNBC cells MDA-MB-231, while downregulating the mRNA and protein expression of vimentin and N-cadherin, while simultaneously upregulating E-cadherin expression. Our results demonstrate that hsa-miR-497-3p regulates EMT in TNBC cells through ZEB1 targeting, as evidenced by the modulation of the expression of vimentin, N-cadherin, and E-cadherin via ZEB1 inhibition. Overall, our study suggests that hsa-miR-497-3p inhibits the proliferation and invasion of TNBC cells through the modulation of EMT via ZEB1 targeting.