Option For Triple-negative Breast Cancer Research Articles

Engineered CAR-NK cells with tolerance to H2O2 and hypoxia can suppress postoperative relapse of triple-negative breast cancers.

Surgical resection is a primary treatment option for triple-negative breast cancer (TNBC) patients, but it is associated with a high rate of postoperative local and metastatic relapse. Although chimeric antigen receptor-engineered natural killer (CAR-NK) cell therapy can specifically recognize and eradicate tumor cells, its therapeutic potency toward TNBCs is markedly suppressed by the hostile tumor microenvironment, which restricts the infiltration, survival and effector functions of CAR-NK cells inside the tumor masses. Herein, HER1-overexpressing TNBC-targeted CAR-NK (HER1-CAR-NK) cells were genetically engineered with catalase to endow them with tolerance toward the high levels of oxidative stress and hypoxia inside TNBC tumors through the catalytic decomposition of hydrogen peroxide, which is a principle reactive oxygen species inside tumors, into O2. We refer to these cells as HER1-CAR-CAT-NK cells. Upon intratumoral fixation with an injectable alginate hydrogel, HER1-CAR-CAT-NK cells enabled sustained tumor hypoxia attenuation and exhibited markedly enhanced persistence and effector functions inside TNBC tumors. As a result, locoregional HER1-CAR-CAT-NK cell therapy not only inhibited the growth of local primary residual tumors, but also elicited systemic antitumor activity to suppress the growth of distant tumors. This study highlights that genetic engineering of HER1-CAR-NK cells with catalase is a promising strategy to suppress the postoperative local and distant relapse of TNBC tumors.

The inositol-requiring enzyme 1 (IRE1) endoplasmic reticulum stress pathway promotes MDA-MB-231 cell survival and renewal in response to the aryl-ureido fatty acid CTU

Current treatment options for triple-negative breast cancer (TNBC) are limited to toxic drug combinations of low efficacy. We recently identified an aryl-substituted fatty acid analogue, termed CTU, that effectively killed TNBC cells in vitro and in mouse xenograft models in vivo without producing toxicity. However, there was a residual cell population that survived treatment. The present study evaluated the mechanisms that underlie survival and renewal in CTU-treated MDA-MB-231 TNBC cells. RNA-seq profiling identified several pro-inflammatory signaling pathways that were activated in treated cells. Increased expression of cyclooxygenase-2 and the cytokines IL-6, IL-8 and GM-CSF was confirmed by real-time RT-PCR, ELISA and Western blot analysis. Increased self-renewal was confirmed using the non-adherent, in vitro colony-forming mammosphere assay. Neutralizing antibodies to IL-6, IL-8 and GM-CSF, as well as cyclooxygenase-2 inhibition suppressed the self-renewal of MDA-MB-231 cells post-CTU treatment. IPA network analysis identified major NF-κB and XBP1 gene networks that were activated by CTU; chemical inhibitors of these pathways and esiRNA knock-down decreased the production of pro-inflammatory mediators. NF-κB and XBP1 signaling was in turn activated by the endoplasmic reticulum (ER)-stress sensor inositol-requiring enzyme 1 (IRE1), which mediates the unfolded protein response. Co-treatment with an inhibitor of IRE1 kinase and RNase activities, decreased phospho-NF-κB and XBP1s expression and the production of pro-inflammatory mediators. Further, IRE1 inhibition also enhanced apoptotic cell death and prevented the activation of self-renewal by CTU. Taken together, the present findings indicate that the IRE1 ER-stress pathway is activated by the anti-cancer lipid analogue CTU, which then activates secondary self-renewal in TNBC cells.

Abstract 6923: Deconvolution of breast cancer dissemination and therapy resistance via single-cell transcriptional lineage tracing

Abstract Chemotherapy remains the most used systemic treatment option for triple-negative breast cancer (TNBC). Lineage tracing studies demonstrated that treatment does not significantly alter clonal composition of primary tumors (PTs). The specific transcriptional phenotype(s) conferring chemoresistance in PTs and metastasis, however, are still largely undetermined, and have not been analyzed at single-clone resolution. We first modelled clinically relevant contexts of chemoresistance in our recently published single-cell lineage tracing approach (DOI: 10.1158/0008-5472.CAN-22-2717), using the standard-of-care combination of adriamycin and cyclophosphamide (A+C) in TNBC xenografts. Treatment was administered in neoadjuvant or adjuvant settings, or both together. In all cases, surgical PT resection was followed by metastatic disease. The neoadjuvant treatment resulted into a stable disease, thus resembling a significant fraction of the treated patients. To investigate clonal and transcriptional dynamics we performed scRNAseq analysis of 12 replicates (3 matched PT-lung replicates for each condition, for a total of 24 samples). Clustering analyses revealed a separation of treatments and tissue of origin. We retrieved a large number of longitudinal clones, including rare clones with high metastatic potential, in all the experimental conditions. A+C did not significantly alter clonal abundances, neither in PTs nor in metastases. Pseudobulk transcriptional analyses revealed key transcriptional traits associated with chemoresistance. Differential expression on longitudinal clones gave insights about transcriptional features of chemoresistant and pro-metastatic clones under chemotherapy. Integration at single-clone level of cluster analysis, pseudobulk and differential expression revealed cystatin (CST) family genes as highly-enriched in the chemoresistant and pro-metastatic phenotype. We are currently validating the role of CST genes in tumor growth, dissemination and chemoresistance in vivo using a panel of specific shRNAs. In parallel, using the same experimental model, we successfully deconvoluted the metastatic cascade through a single-cell lineage tracing approach on matched PT-CTC (circulating tumor cells)-lung replicates. scRNAseq analyses of pro-metastatic, circulating and metastatic clones is ongoing. Our preliminary data showed that all the dominant clones in the metastatic lungs are also found as CTCs in the bloodstream, thus suggesting that all pro-metastatic cells are also capable of surviving in the bloodstream and reinforcing our concept of pro-metastatic clone. This approach led us to gain a complete overview around clonal and transcriptional evolution of breast cancer dissemination. Citation Format: Alberto Dalmasso, Andrea Cossa, Giulia Bertolini, Niccolò Roda, Ilaria Servidio, Francesco Antonio Tucci, Salvatore Pece, Gabriella Sozzi, Pier Giuseppe Pelicci. Deconvolution of breast cancer dissemination and therapy resistance via single-cell transcriptional lineage tracing [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 6923.

Crocin inhibit the metastasis of MDA-MB-231 cell line by suppressing epithelial to mesenchymal transition through WNT/β-catenin signalling pathway.

Triple-negative breast cancer has the poorest prognosis and survival rates compared to other breast cancer subtypes due to its invasive behaviours. This type of cancer does not respond to biological therapies and exhibits resistance to available treatment options. Therefore, it is imperative to discover new therapeutics to address this challenge. In this study, a TNBC cell line was utilized to investigate the anti-metastatic effect of crocin on the Wnt/β-catenin pathway. Cell proliferation was assessed using the MTT assay, and the effects of crocin on migration were monitored through transwell and wound healing experiments. The expression of specific epithelial-mesenchymal transition marker genes was evaluated using real-time polymerase chain reaction, and β-catenin expression was also examined through real-time polymerase chain reaction. The findings revealed that crocin significantly inhibits cell proliferation and migration of tumour cells in a dose-dependent manner. Moreover, crocin decreased the expression of Vimentin, Snail, Zeb-1, and β-catenin. Additionally, crocin increased the expression of E-cadherin in the MDA-MB-231 cell line. The results demonstrated an association between crocin and the Wnt/β-catenin signalling pathway. In conclusion, this study establishes that crocin holds promise as a potential therapeutic option for triple-negative breast cancer.

The Marine Natural Compound Dragmacidin D Selectively Induces Apoptosis in Triple-Negative Breast Cancer Spheroids.

Cancer cells grown in 3D spheroid cultures are considered more predictive for clinical efficacy. The marine natural product dragmacidin D induces apoptosis in MDA-MB-231 and MDA-MB-468 triple-negative breast cancer (TNBC) spheroids within 24 h of treatment while showing no cytotoxicity against the same cells grown in monolayers and treated for 72 h. The IC50 for cytotoxicity based on caspase 3/7 cleavage in the spheroid assay was 8 ± 1 µM in MDA-MB-231 cells and 16 ± 0.6 µM in MDA-MB-468 cells at 24 h. No cytotoxicity was seen at all in 2D, even at the highest concentration tested. Thus, the IC50 for cytotoxicity in the MTT assay (2D) in these cells was found to be >75 µM at 72 h. Dragmacidin D exhibited synergy when used in conjunction with paclitaxel, a current treatment for TNBC. Studies into the signaling changes using a reverse-phase protein array showed that treatment with dragmacidin D caused significant decreases in histones. Differential protein expression was used to hypothesize that its potential mechanism of action involves acting as a protein synthesis inhibitor or a ribonucleotide reductase inhibitor. Further testing is necessary to validate this hypothesis. Dragmacidin D also caused a slight decrease in an invasion assay in the MDA-MB-231 cells, although this failed to be statistically significant. Dragmacidin D shows intriguing selectivity for spheroids and has the potential to be a treatment option for triple-negative breast cancer, which merits further research into understanding this activity.

Site-selective superassembly of biomimetic nanorobots enabling deep penetration into tumor with stiff stroma

Chemotherapy remains as the first-choice treatment option for triple-negative breast cancer (TNBC). However, the limited tumor penetration and low cellular internalization efficiency of current nanocarrier-based systems impede the access of anticancer drugs to TNBC with dense stroma and thereby greatly restricts clinical therapeutic efficacy, especially for TNBC bone metastasis. In this work, biomimetic head/hollow tail nanorobots were designed through a site-selective superassembly strategy. We show that nanorobots enable efficient remodeling of the dense tumor stromal microenvironments (TSM) for deep tumor penetration. Furthermore, the self-movement ability and spiky head markedly promote interfacial cellular uptake efficacy, transvascular extravasation, and intratumoral penetration. These nanorobots, which integrate deep tumor penetration, active cellular internalization, near-infrared (NIR) light-responsive release, and photothermal therapy capacities into a single nanodevice efficiently suppress tumor growth in a bone metastasis female mouse model of TNBC and also demonstrate potent antitumor efficacy in three different subcutaneous tumor models.

Impact of AKT1 on cell invasion and radiosensitivity in a triple negative breast cancer cell line developing brain metastasis.

The PI3K/AKT pathway is activated in 43-70% of breast cancer (BC)-patients and promotes the metastatic potential of BC cells by increasing cell proliferation, invasion and radioresistance. Therefore, AKT1-inhibition in combination with radiotherapy might be an effective treatment option for triple-negative breast cancer (TNBC)-patients with brain metastases. The impact of AKT1-knockout (AKT1_KO) and AKT-inhibition using Ipatasertib on MDA-MB-231 BR cells was assessed using in vitro cell proliferation and migration assays. AKT1-knockout in MDA-MB-231BR cells was performed using CRISPR/Cas9. The effect of AKT1-knockout on radiosensitivity of MDA-MB-231BR cell lines was determined via colony formation assays after cell irradiation. To detect genomic variants in AKT1_KO MDA-MB-231BR cells, whole-genome sequencing (WGS) was performed. Pharmacological inhibition of AKT with the pan-AKT inhibitor Ipatasertib led to a significant reduction of cell viability but did not impact cell migration. Moreover, only MDA-MB-231BR cells were sensitized following Ipatasertib-treatment. Furthermore, specific AKT1-knockout in MDA-MB-231BR showed reduced cell viability in comparison to control cells, with significant effect in one of two analyzed clones. Unexpectedly, AKT1 knockout led to increased cell migration and clonogenic potential in both AKT1_KO clones. RNAseq-analysis revealed the deregulation of CTSO, CYBB, GPR68, CEBPA, ID1, ID4, METTL15, PBX1 and PTGFRN leading to the increased cell migration, higher clonogenic survival and decreased radiosensitivity as a consequence of the AKT1 knockout in MDA-MB-231BR. Collectively, our results demonstrate that Ipatasertib leads to radiosensitization and reduced cell proliferation of MDA-MB-231BR. AKT1-inhibition showed altered gene expression profile leading to modified cell migration, clonogenic survival and radioresistance in MDA-MB-231BR. We conclude, that AKT1-inhibition in combination with radiotherapy contribute to novel treatment strategies for breast cancer brain metastases.

Polymeric graphene oxide nanoparticles loaded with doxorubicin for combined photothermal and chemotherapy in triple negative breast cancer

Combining photothermal and chemotherapy is an emerging strategy for tumor irradiation in a minimally invasive manner, utilizing photothermal transduction agents and anticancer drugs. The present work developed a 2D carbon nanomaterial graphene oxide (GO)-based nanoplatform that converted to 3D colloidal spherical structures upon functionalization with an amphiphilic polymer mPEG-PLA (1, 0.5/1/2) and entrapped doxorubicin (Dox) physically. The Dox@GO(mPP) (1/0.5) NPs displayed the least particle size (161 nm), the highest stability with no aggregation, the highest Dox loading (6.3 %) and encapsulation efficiency (70 %). The therapeutic efficacy was determined in vitro and in vivo using murine (4 T1) and human triple-negative breast cancer cells (MDA-MB-231), and 4 T1-Luc-tumor bearing mouse models. The results demonstrated that the Dox@GO(mPP) (1/0.5) NPs treatment with laser (+L) (808 nm) was highly efficient in inducing apoptosis, cell cycle arrest (G2/M) phase, significant cytotoxicity, mitochondrial membrane depolarization, ROS generation, and photothermal effect leading to a higher proportion of cell death than free Dox, and Dox@GO(mPP) (1/0.5) NPs (−L). The anticancer studies in mice harboring the 4 T1-Luc tumor showed that combination of Dox@GO(mPP) (1/0.5) NPs (+L) effectively reduced tumor development and decreased lung metastasis. The developed nanoplatform could be a promising combination chemo-photothermal treatment option for triple-negative breast cancer.

Natural Blockers of PD-1/PD-L1 Interaction for the Immunotherapy of Triple-Negative Breast Cancer-Brain Metastasis.

The limited treatment options for triple-negative breast cancer with brain metastasis (TNBC-BM) have left the door of further drug development for these patients wide open. Although immunotherapy via monoclonal antibodies has shown some promising results in several cancers including TNBC, it cannot be considered the most effective treatment for brain metastasis. This is due to the protective role of the blood-brain barrier (BBB) which limits the entrance of most drugs, especially the bulky ones such as antibodies, to the brain. For a drug to traverse the BBB via passive diffusion, various physicochemical properties should be considered. Since natural medicine has been a key inspiration for the development of the majority of current medicines, in this paper, we review several naturally-derived molecules which have the potential for immunotherapy via blocking the interaction of programmed cell death protein-1 (PD-1) and its ligand, PD-L1. The mechanism of action, physicochemical properties and pharmacokinetics of these molecules and their theoretical potential to be used for the treatment of TNBC-BM are discussed.

Apoptosis, Proliferation, and Autophagy Are Involved in Local Anesthetic-Induced Cytotoxicity of Human Breast Cancer Cells.

Breast cancer accounts for almost one quarter of all female cancers worldwide, and more than 90% of those who are diagnosed with breast cancer undergo mastectomy or breast conservation surgery. Local anesthetics effectively inhibit the invasion of cancer cells at concentrations that are used in surgical procedures. The limited treatment options for triple-negative breast cancer (TNBC) demonstrate unmet clinical needs. In this study, four local anesthetics, lidocaine, levobupivacaine, bupivacaine, and ropivacaine, were applied to two breast tumor cell types, TNBC MDA-MB-231 cells and triple-positive breast cancer BT-474 cells. In addition to the induction of apoptosis and the suppression of the cellular proliferation rate, the four local anesthetics decreased the levels of reactive oxygen species and increased the autophagy elongation indicator in both cell types. Our combination index analysis with doxorubicin showed that ropivacaine had a synergistic effect on the two cell types, and lidocaine had a synergistic effect only in MDA-MB-231 cells; the others had no synergistic effects on doxorubicin. Lidocaine contributed significantly to the formation of autophagolysosomes in a dose-dependent manner in MDA-MB-231 cells but not in BT-474 cells. Our study demonstrated that the four local anesthetics can reduce tumor growth and proliferation and promote apoptosis and autophagy.

Association of BRCAness with taxane resistance in triple-negative breast cancer: A study of 7 cases

Introduction: Chemotherapy is the only systemic treatment option for triple-negative breast cancer (TNBC) patients, and is often used in combination with anthracycline and taxane. However, it was reported that many TNBCs show BRCA dysfunction, and are sensitive to DNA-damaging agents, but tend to be resistant to mitotic poisons, such as taxanes. Case Series: Triple-negative breast cancer patients who underwent neoadjuvant chemotherapy with anthracycline followed by taxane were analyzed. Clinical responses to taxane were evaluated by the percentage of shrinkage in tumor size after anthracycline treatment. BRCAness was analyzed by mutiplex ligation-dependent probe amplification (MLPA) in core-needle biopsy specimens of 7 patients with progressive disease or stable disease after taxane treatment. BRCAness scores of the 7 patients were between 0.779 and 1.000 (0.939 ± 0.084), and all were categorized as having BRCAness. Conclusion: Patients resistant to taxane were categorized as having BRCAness by MLPA. Mutiplex ligation-dependent probe amplification may hence be a promising method to identify TNBC patients with taxane resistance.

Co-targeting triple-negative breast cancer cells and endothelial cells by metronomic chemotherapy inhibits cell regrowth and migration via downregulation of the FAK/VEGFR2/VEGF axis and autophagy/apoptosis activation.

High-dose standard-of-care chemotherapy is the only option for triple-negative breast cancer (TNBC) patients, which eventually die due to metastatic tumors. Recently, metronomic chemotherapy (mCHT) showed advantages in treating TNBCs leading us to investigate the anti-metastatic and anti-angiogenic potential of metronomic 5-Fluorouracil plus Vinorelbine (5-FU+VNR) on endothelial cells (ECs) and TNBCs in comparison to standard treatment (STD). We found that 10-fold lower doses of 5-FU+VNR given mCHT vs. STD inhibits cell proliferation and survival of ECs and TNBC cells. Both schedules strongly affect ECs migration and invasion, but in TNBC cells mCHT is significantly more effective than STD in impairing cell migration and invasion. The two treatments disrupt FAK/VEGFR/VEGF signaling in both ECs and TNBC cells. mCHT, and to a much lesser extent STD treatment, induces apoptosis in ECs, whereas it switches the route of cell death from apoptosis (as induced by STD) to autophagy in TNBC cells. mCHT-treated TNBCs-derived conditioned medium also strongly affects ECs' migration, modulates different angiogenesis-associated proteins, and hampers angiogenesis in matrix sponge in vivo. In conclusion, mCHT administration of 5-FU+VNR is more effective than STD schedule in controlling cell proliferation/survival and migration/invasion of both ECs and TNBC cells and has a strong anti-angiogenic effect. Our data suggest that the stabilization of tumor growth observed in TNBC patients treated with mCHT therapy schedule is likely due not only to direct cytotoxic effects but also to anti-metastatic and anti-angiogenic effects.

Comparative efficacy and safety of first-line neoadjuvant treatments in triple-negative breast cancer: systematic review and network meta-analysis.

Neoadjuvant treatment options for triple-negative breast cancer (TNBC) are abundant, but the efficacy of different combinations of treatment options remains unclear. Our network meta-analysis aimed to evaluate the effectiveness and safety of various neoadjuvant treatment options in patients with TNBC. Literature reports published before March 31, 2022, were retrieved from the PubMed, Embase, Cochrane Library, main oncology conference of the European Society of Medical Oncology, American Society of Clinical Oncology, and San Antonio Breast Cancer Symposium databases. Pairwise and Bayesian network meta-analyses were performed to compare direct and indirect evidence, respectively. The primary outcome was pathological complete response (pCR). Comparison of efficiency between different treatment regimens was made by HRs and 95% confidence intervals (CIs). Overall, 26 studies, including 9714 TNBC patients, were assessed in this network meta-analysis. Results indicated that the pCR of immune checkpoint inhibitors plus platinum-containing regimens is better than other joint regimens. PCR rate of neoadjuvant chemotherapy regimens containing bevacizumab, platinum, poly(ADP-ribose) polymerase inhibitors, and immune checkpoint inhibitors was higher than those of standard chemotherapy agents. By performing a conjoint analysis of the pCR rate and safety endpoints, we found that immune checkpoint inhibitors plus platinum-containing regimens were well balanced in terms of efficacy and toxicity. Considering the efficacy and acceptable adverse events, neoadjuvant chemotherapy based on immune checkpoint inhibitors plus platinum may be considered as an option for patients with TNBC.

Clinicopathological Features of Neoadjuvant Chemotherapy Response to Triple Negative Breast Cancer in Dr. Hasan Sadikin General Hospital

BackgroundTriple Negative Breast Cancer (TNBC) accounts for 9-17% of all breast cancer diagnoses. TNBC has a high proliferation index and a poor prognosis with a higher response rate to neoadjuvant chemotherapy, but does not correlate with Overall Survival (OS) due to chemoresistence in more than 50% of TNBC. Neoadjuvant chemotherapy with anthracycline (doxorubicin) based regimens in combination with fluorouracil and cyclophosphamide (FAC) is still an option for TNBC. The aim of this study was to determine association between clinicopathological profile and response to neoajuvan chemotherapy in TNBC at Dr. Hasan Sadikin Bandung which is a referral hospital in West Java.MethodsThis study used an analytic observational method with a cross-sectional design. The research sample consisted of 40 TNBC cases from January 2017 to December 2019 at Dr. Hasan Sadikin hospital. Data obtained from medical records and archives of the Anatomical Pathology Laboratory consist of clinical response to neoadjuvant chemotherapy, age, tumor size, lymph node metastases and distant metastases, clinical stage, type of histopathology and lymphovascular vessel invasion.ResultsIn 40 cases of TNBC, 20 cases responded and 20 cases did not respond to neoadjuvant chemotherapy. In the non-response group, there were 90% of cases with histopathologic type invasive carcinoma of no special type and 75% showed invasion of lymphovascular vessels. There were no significant differences in age, tumor size, lymphovascular vessel invasion, stage, or histopathological type in the response and non-response groups.ConclusionThere is no correlation between clinicopathological features and neoadjuvant chemotherapy response in the case of Triple Negative Breast Cancer (TNBC). This can be caused by other factors including high heterogeneous tumor microenvironment (TME).

Therapeutic methods in the treatment of triple-negative breast cancer - a review

Breast cancer is a common female malignancy characterized by the presence of multiple subtypes taking into account, among other things, hormonal activity. The purpose of this study is to show the therapeutic options for triple-negative breast cancer (TNBC). A review of the literature in databases such as PubMed, Google Scholar, and Web of Science by keywords was performed, taking into account papers from 2017-2022. The main therapeutic approaches are surgical intervention and systemic chemotherapy (neoadjuvant and adjuvant). Unsatisfactory results from chemotherapy have prompted researchers to work on other methods to combat TNBC. Clinical trials are being conducted on the use of immunotherapy focusing mainly on molecules against PD-1, PD-L1, and CTLA-4. Targeted therapy is the latest proposed form of therapy, which offers the possibility of introducing a drug in the future that will be tailored to the patient's needs limiting the negative therapeutic impact.

Research progress on immunotherapy in triple‑negative breast cancer (Review).

Triple-negative breast cancer (TNBC) is a highly heterogeneous and aggressive malignancy. Due to the absence of estrogen receptors and progesterone receptors and the lack of overexpression of human epidermal growth factor receptor 2, TNBC responds poorly to endocrine and targeted therapies. As a neoadjuvant therapy, chemotherapy is usually the only option for TNBC; however, chemotherapy may induce tumor resistance. The emergence of immunotherapy as an adjuvant therapy is expected to make up for the deficiency of chemotherapy. Most of the research on immunotherapies has been performed on advanced metastatic TNBC, which has provided significant clinical benefits. In the present review, possible immunotherapy targets and ongoing immunotherapy strategies were discussed. In addition, progress in research on immune checkpoint inhibitors in early TNBC was outlined.

Huaier Induces Immunogenic Cell Death Via CircCLASP1/PKR/eIF2α Signaling Pathway in Triple Negative Breast Cancer.

Triple-negative breast cancer (TNBC) is the most lethal breast cancer subtype owing to the lack of targeted therapeutic strategies. Immunogenic cell death (ICD), a modality of regulated cancer cell death, offered a novel option for TNBC via augmenting tumor immunogenic microenvironment. However, few ICD-inducing agents are currently available. Here, we showed that Trametes robiniophila Murr (Huaier) triggered ICD in TNBC cells by promoting cell surface calreticulin (CRT) exposure, and increasing release of adenosine triphosphate (ATP) and high-mobility group protein B1 (HMGB1). Co-culturing with Huaier-treated TNBC cells efficiently enhanced the maturation of dendritic cells (DCs), which was further validated via cell-based vaccination assay. In the xenograft mouse model, oral administration of Huaier led to tumor-infiltrating lymphocytes (TILs) accumulation and significantly delayed tumor growth. Besides, depletion of endogenous T cells obviously abrogated the effect. Mechanically, Huaier could elicit endoplasmic reticulum (ER) stress-associated ICD through eIF2α signaling pathway. Further studies revealed that circCLASP1 was involved in the Huaier-induced immunogenicity by binding with PKR in the cytoplasm and thus blocking its degradation. Taken together, we highlighted an essential role of circCLASP1/PKR/eIF2α axis in Huaier-induced ICD. The findings of our study carried significant translational potential that Huaier might serve as a promising option to achieve long-term tumor remission in patients with TNBC.

NDC80 Enhances Cisplatin-resistance in Triple-negative Breast Cancer

Chemotherapy is a standard systemic treatment option for triple-negative breast cancer (TNBC). Cisplatin has been used to treat TNBC, but frequently leads to cisplatin resistance in patients. The aim of our study was to investigate cisplatin-resistant mechanism in TNBC. To identify the potential genes and pathways relative to cisplatin resistance, GSE103115 data were analyzed by the Limma package and Gene set enrichment analysis (GSEA). TNBC data from TCGA, GSE76250 and GSE115275 datasets were used to calculate NDC80 expression. Immunohistochemistry detected NDC80 protein expression in TNBC tissues from patients before and after cisplatin treatment. After expose to cisplatin treatment, the viability and proliferation of TNBC cells were measured by CCK-8 and colony formation assays, respectively. NDC80 was regarded as a cisplatin-resistant gene because after cisplatin treatment NDC80 was downregulated in cisplatin-sensitive cells but was upregulated in cisplatin-resistant cells. NDC80 was over-expressed in TNBC tissues compared to normal tissues. Furthermore, NDC80 expression in TNBC patients was increased after cisplatin treatment. Cisplatin-sensitive TNBC patients showed lower NDC80 expression than cisplatin-resistant patients. Additionally, NDC80 expression was correlated with clinical stages, tumor size and chemotherapy of TNBC patients. Moreover, NDC80 overexpression promoted the viability and proliferation of TNBC cells and enhanced the cells resistance to cisplatin. The potential pathways relative to cisplatin resistance were obtained, such as p53 signaling pathway and Oxidative phosphorylation. These findings provide new insights for understanding the mechanism of cisplatin resistance in TNBC, and NDC80 may be a potential therapeutic target for TNBC treatment.

Abstract P5-17-10: Anti-progranulin (GP88) antibody AG01 inhibitory effect on the growth of triple negative breast cancer cells

Abstract Background: Triple negative breast cancer (TNBC) is characterized by invasiveness and short survival. Identifying novel TNBC targeted therapies to potentiate standard of care (SOC) therapy, is an unmet need. Progranulin (PGRN/GP88) is a biological driver of tumorigenesis, survival, and drug resistance in several cancers including breast cancer (BC). PGRN/GP88 tissue expression is an independent prognostic factor of recurrence while elevated serum PGRN/GP88 level is associated with poor outcomes such as progression of disease and shortened survival. Since PGRN/GP88 expression is elevated in 30% TNBC, we investigated the effect of inhibiting PGRN/GP88 effect on the proliferation and tumor growth of triple negative breast cancer cells. Methods: For this purpose, we have developed a neutralizing anti-human PGRN/GP88 monoclonal antibody AG01 and examined its effect on the proliferation, migration, signaling pathway activation and biomarker expression of two TNBC cell lines MDA-MB-231 and HS578-T expressing PGRN/GP88, both in vitro and in vivo. Results: The inhibition of PGRN/GP88 action by AG01 treatment reduced proliferation and migration in a dose-and time-dependent fashion in MDA-MB-231 and HS578-T cells. Western blot analysis showed decreased expression of phosphorylated protein kinases p-Src, p-AKT and p-ERK involved in proliferation and survival upon AG01 treatment for both cell lines. Transwell assay showed that AG01 treatment inhibited migration and invasion in a dose-dependent fashion. Microarray analysis of several oncoproteins in cells treated with AG01 or control antibody demonstrated the inhibition of the expression of several markers of migration and angiogenesis. In vivo xenograft studies with MDA-MB-231 cells injected in athymic nude mice showed that AG01 treatment inhibited tumor growth as well as Ki67 expression, mitotic index and microvessel counts when compared to antibody control treated mice. In vivo dose response of AG01 in MDA-MB-231 tumor bearing mice will be provided. Conclusion: TNBC is a disease with poor prognosis in need of novel targeted therapeutic solutions. PGRN/GP88 represents a therapeutic target for TNBC with two companion diagnostics (tissue test and ELISA to measure GP88 circulating levels). Blocking PGRN/GP88 with AG01 antibody treatment will provide novel targeted therapeutic option for TNBC which could address the issue of toxicity, and unresponsiveness associated with SOC. This work is supported by a grant CA 224718 from the National Cancer Institute to GS. Citation Format: Ginette Serrero, Rupa Guha, Jianping Dong, Binbin Yue. Anti-progranulin (GP88) antibody AG01 inhibitory effect on the growth of triple negative breast cancer cells [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P5-17-10.

Regression of Triple-Negative Breast Cancer in a Patient-Derived Xenograft Mouse Model by Monoclonal Antibodies against IL-12 p40 Monomer.

Although some therapies are available for regular breast cancers, there are very few options for triple-negative breast cancer (TNBC). Here, we demonstrated that serum level of IL-12p40 monomer (p40) was much higher in breast cancer patients than healthy controls. On the other hand, levels of IL-12, IL-23 and p40 homodimer (p402) were lower in serum of breast cancer patients as compared to healthy controls. Similarly, human TNBC cells produced greater level of p40 than p402. The level of p40 was also larger than p402 in serum of a patient-derived xenograft (PDX) mouse model. Accordingly, neutralization of p40 by p40 mAb induced death of human TNBC cells and tumor shrinkage in PDX mice. While investigating the mechanism, we found that neutralization of p40 led to upregulation of human CD4+IFNγ+ and CD8+IFNγ+ T cell populations, thereby increasing the level of human IFNγ and decreasing the level of human IL-10 in PDX mice. Finally, we demonstrated the infiltration of human cytotoxic T cells, switching of tumor-associated macrophage M2 (TAM2) to TAM1 and suppression of transforming growth factor β (TGFβ) in tumor tissues of p40 mAb-treated PDX mice. Our studies identify a possible new immunotherapy for TNBC in which p40 mAb inhibits tumor growth in PDX mice.