Triple-negative Breast Cancer Malignancy Research Articles

Extracellular matrix markerLAMC2 targets ZEB1 to promote TNBC malignancy via up-regulating CD44/STAT3 signaling pathway.

Triple negative breast cancer (TNBC) is a heterogeneous and aggressive disease characterized by a high risk of mortality and poor prognosis. It has been reported that Laminin γ2 (LAMC2) is highly expressed in a variety of tumors, and its high expression is correlated with cancer development and progression. However, the function and mechanism by which LAMC2 influences TNBC remain unclear. Kaplan-Meier survival analysis and Immunohistochemical (IHC) staining were used to examine the expression level of LAMC2 in TNBC. Subsequently, cell viability assay, wound healing and transwell assay were performed to detect the function of LAMC2 in cell proliferation and migration. A xenograft mouse model was used to assess tumorigenic function of LAMC2 in vivo. Luciferase reporter assay and western blot were performed to unravel the underlying mechanism. In this study, we found that higher expression of LAMC2 significantly correlated with poor survival in the TNBC cohort. Functional characterization showed that LAMC2 promoted cell proliferation and migration capacity of TNBC cell lines via up-regulating CD44. Moreover, LAMC2 exerted oncogenic roles in TNBC through modulating the expression of epithelial-mesenchymal transition (EMT) markers. Luciferasereporterassay verified that LAMC2 targeted ZEB1to promote its transcription.Interestingly, LAMC2 regulated cell migration in TNBC via STAT3 signaling pathway. LAMC2 targeted ZEB1 via activating CD44/STAT3 signaling pathway to promote TNBC proliferation and migration, suggesting that LAMC2 could be a potential therapeutic target in TNBC patients.

Abstract 549: PDZK1 sensitizes TNBC cells to erlotinib via promoting c-Cbl-mediated EGFR degradation and inhibiting EGFR phosphorylation

Abstract Background: Triple-negative breast cancer (TNBC) is lack of effective targeted therapies. Epidermal growth factor receptor (EGFR) is a potential therapeutic target for TNBC. However, TNBC is resistant to EGFR-targeted drugs in clinical trials, and the tolerance mechanism remains unclear. This study aimed to elucidate the possible resistance mechanism for TNBC to EGFR-targeted therapy and how sensitize TNBC cells to erlotinib. Methods: PDZ domain containing 1 (PDZK1) correlated with TNBC development was screened out by bioinformatics analysis and its correlation with resistance to erlotinib was identified by western blotting (WB). Its interaction with EGFR and structural basis were determined by GST-Pull down and coimmunoprecipitation. Its regulation on EGFR signaling activation and expression level were detected by WB in PDZK1 overexpression and knockdown TNBC cells, xenograft tissues and correlation analyses. Correlation was performed by gene set enrichment analysis (GSEA) and immunohistochemistry of tissue microarray followed by Pearson analysis. TNBC-suppressing effects of PDZK1 and its sensitizing effects on erlotinib were investigated using cell viability assay, colony-forming assay, wound healing assay, Matrigel invasion assay and xenograft model in combination with PDZK1 wild type/mutant transfection and rescue experiment. Results: Here we found that PDZK1 was correlated with TNBC development and its level was downregulated in erlotinib-resistant TNBC cells, suggesting that PDZK1 downregulation was related to erlotinib resistance in TNBC. PDZK1 bound with EGFR. Through the interaction, PDZK1 promoted EGFR degradation by enhancing the binding of EGFR with c-Cbl and inhibited EGFR phosphorylation by hindering EGFR dimerization. PDZK1 was specifically downregulated in TNBC tissues and was correlated with poor prognosis of TNBC. Functional assays in vitro and in vivo showed that PDZK1 suppressed TNBC development. Restoring EGFR expression and kinase inhibitor treatment reversed the malignancy caused by PDZK1 overexpression and knockdown, respectively. PDZK1 wild type, but not mutant overexpression enhanced the inhibitory effect of erlotinib on EGFR signaling and TNBC malignancy in vitro and in vivo. Conclusion: PDZK1 is a significant prognostic factor for TNBC and a potential molecular therapeutic target for TNBC to reverse the tolerance of TNBC cells to erlotinib. Citation Format: Junfang Zheng, Yuanzhen Ma, Zhiyu Fang, Yijun Qi. PDZK1 sensitizes TNBC cells to erlotinib via promoting c-Cbl-mediated EGFR degradation and inhibiting EGFR phosphorylation [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 549.

Abstract 5634: Tristetraprolin induces an antitumorigenic phenotype in triple negative breast cancer via a novel non-canonical mechanism

Abstract The ultimate cause of death for most triple negative breast cancer (TNBC) patients is metastatic disease, which has a five-year survival rate of 12.8%. This low survival rate is partly due to the lack of targeted treatments for metastatic TNBC, resulting from the heterogeneity of the disease. As such, further research is needed to identify novel molecular mechanisms that can be targeted to suppress TNBC malignancy. Tristetraprolin (TTP) is an RNA-binding protein that binds to AU-rich elements (AREs) in the 3’ UTRs of select mRNAs, including many that encode proteins involved in cancer-related processes, and targets these mRNAs for degradation. Loss of TTP in tumors correlates with increased disease severity and decreased survival, suggesting a role as a tumor suppressor in multiple cancers, including breast cancer. While previous research has shown that TTP can suppress proliferation in breast cancer, the mechanism remains weakly defined. To elucidate how TTP impacts tumorigenic phenotypes in advanced breast cancer, we stably transfected a FLAG-TTP-expressing construct into three aggressive and metastatic TNBC cell lines. We analyzed TTP-induced changes in gene expression patterns among these cell lines using RNA-sequencing and observed that TTP alters the expression levels of many genes. Gene Set Enrichment Analysis (GSEA) of our datasets revealed that TTP affects multiple pathways, including significant suppression of pathways that promote cell growth, various metabolic processes contributing to tumor growth, and the response to hypoxia. As these pathways highly associated with tumorigenesis, we hypothesized that TTP would attenuate multiple tumor phenotypes. Our subsequent functional analyses revealed that TTP potently suppressed four tumor phenotypes in these cell models: cell proliferation, stem cell frequency, migration, and invasiveness. We hypothesized that inhibition of proliferation was mediated by cell cycle alterations, however, flow cytometry analysis revealed no substantial cell cycle perturbations between TTP-expressing cells and controls. Further analysis of cell cycle regulators revealed minimal changes in expression of proteins encoded by known or suspected TTP target mRNAs. Actinomycin D assays surprisingly revealed that TTP had no effect on the decay kinetics of several known TTP targets, suggesting that TTP’s antitumorigenic properties observed in TNBC cells are independent of its RNA-destabilizing function. To confirm this finding, we constructed cell models expressing an RNA-binding defective mutant of TTP, C147R, which recapitulated suppression of the four tumorigenic phenotypes seen with the wild-type protein. Collectively, these findings reveal that expression of TTP can potently suppress several oncogenic phenotypes in TNBC cells via a mechanism independent of its canonical RNA-binding/destabilizing functions. Citation Format: Julia L. Rutherford, Megan B. Stemberger, Rohaan Mahmud, Christina R. Ross, Elizabeth J. White, Gerald M. Wilson. Tristetraprolin induces an antitumorigenic phenotype in triple negative breast cancer via a novel non-canonical mechanism [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 5634.

Abstract 2137: Racial disparities in triple-negative breast cancer (TNBC) mortality rates in Hampton Roads Virginia and the effects of SIAH expression on prognosis

Abstract Background: While high-resolution imaging and advancements in therapies have significantly improved breast cancer survival rates, 43,170 breast cancer patients will die in the United States in 2023 alone. Triple-negative breast cancer (TNBC) is the most aggressive breast cancer subtype and disproportionately affects BRCA1 mutation carriers and young black women. Black/African American (AA) patients have the highest mortality and the shortest survival of any racial/ethnic group in the US. Persistent cancer racial disparities remain due to a variety of risk factors. The SEER/CDC data show an 8% lower breast cancer incidence rate and a 41% higher mortality rate in Black/AA patients compared to their white counterparts. Methods: Chart review was conducted using Sentara MD Office/EPIC and VOA iKnowMedicine portals to update tumor relapse, metastasis, and survival in 577 TNBC patients. Supported by strong evidence in developmental, evolutionary, and cancer biology, we hypothesize that persistent EGFR/K-RAS/SIAH pathway activation is a major driving force of TNBC malignancy, racial disparity, early relapse, and high mortality. We propose to integrate SIAH expression to augment the existing clinicopathological parameters to improve patient risk stratification, therapy quantification, and relapse/survival prediction at the 1st-line neoadjuvant settings. Results: We report that cancer disparity and high mortality rates are even more pronounced in our racially-diverse communities in Hampton Roads Virginia. We discovered that SIAH is a tumor-specific, therapy-responsive, and prognostic biomarker in TNBC. High SIAH expression in residual tumors reflects tumor-driving EGFR/K-RAS/SIAH pathway activation (ON) that will predict cancer disparity, treatment resistance, early relapse, and poor survival. Low SIAH expression in residual tumors reflect EGFR/K-RAS/SIAH pathway inactivation (OFF) that will predict tumor remission and prolonged survival. Conclusion: We detect a major racial disparity of TNBC patients at Sentara-EVMS-VOA. Our local Black/AA TNBC patients have a 1.6-fold higher mortality rate than their White counterparts. Encouraged by our preliminary data, we aim to develop a SIAH-centered biomarker panel by measuring the EGFR/K-RAS/SIAH pathway activation (ON)/inactivation (OFF), and use SIAH as a new prognostic biomarker to risk stratify patients, detect cancer racial disparities, forecast tumor relapse, and predict patient survival at 1st-line neoadjuvant settings. By targeting SIAH, individualized treatments can be created to allow for increased survival rates in at risk individuals with more aggressive TNBCs. Citation Format: Claire B. Piatak, Taylor N. Drake, Ashleigh Hannah, Jonathan Baker, Caroline L. Dasom, Emily L. Breeding, Janet S. Winston, Billur Samli, Rick Jansen, Michael Danso, Richard A. Hoefer, Amy H. Tang. Racial disparities in triple-negative breast cancer (TNBC) mortality rates in Hampton Roads Virginia and the effects of SIAH expression on prognosis [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 2137.

Abstract 7664: Early detection of racial disparity and treatment resistance in triple negative breast cancer

Abstract Introduction: Triple-negative breast cancer (TNBC) is an aggressive breast cancer subtype that disproportionately affects BRCA1 mutation carriers and young Black/African American (AA) women. Black/AA patients have the highest mortality and the shortest survival of any racial/ethnic group in the US. With the approval of pembrolizumab, the addition of immune checkpoint blockade (ICB) to neoadjuvant chemotherapy (NACT) has become the standard of care (SOC) for high-risk early-stage TNBC. The pathologic complete response (pCR) is a reliable prognostic marker that correlates with tumor remission and good outcome, whereas pathologic incomplete response (pIR) with high residual cancer burden (RCB) is often associated with early relapse, treatment resistance, and poor survival. Many similarly-treated patients with identical TNM and RCB classifications still experience racial disparity, different relapse rates, and disparate survival. Current methods fall short in predicting tumor recurrence/chemo-resistance/patient survival with high accuracy in the clinic. Methods: We detected a major racial disparity in our large regional cohorts of TNBC patients (> 1,000 patients), of which 48% patients are Black/AA and 48% patients are white patients, at the Sentara Cancer Network and VCU Massey Comprehensive Cancer Center, that have historically provided excellent healthcare and quality cancer care to the social-economically-disadvantaged, medically underserved, and underinsured racial/ethnic minorities in low income communities in Virginia. Despite Sentara/VCU’s best efforts, Black/AA breast cancer patients still suffer 70-100% higher MBC mortality, and the worst survival compared to their white counterparts, based on our clinical studies and the SEER/CDC databases. Result: We showed that persistent EGFR/RAS/SIAH pathway activation is a major driving force of TNBC malignancy. The most downstream and evolutionarily conserved signaling gatekeeper, SIAH, is an RING domain E3 ligase that is a high-resolution prognostic biomarker for patient risk stratification and racial disparity prediction in TNBC. High SIAH expression in residual tumors reflects ineffective NACT/IO therapy and persistent EGFR/K-RAS/SIAH pathway activation (ON) that drives tumor relapse, resistance, and reduced survival. Low SIAH expression in residual tumors reflects effective NACT/IO therapy and EGFR/K-RAS/SIAH pathway inactivation (OFF) that predicts tumor remission, good outcome, and prolonged survival. We found that SIAH expression is 2.0-fold higher in Black/AA patients’ residual tumors than in the white patients’ residual tumors, mirroring a 1.8-2.0-fold higher death rates in the Black/AA patients than the white patients. Conclusion: In this study, we demonstrate the prognostic power of SIAH for patient risk stratification, therapy quantification, and relationship to cancer racial disparity in TNBC. Citation Format: Amy H. Tang, Richard A. Hoefer, Mary L. Guye, Billur Samli, Janet S. Winston, Jennifer Koblinski, Valentina Robila, Michael O. Idowu, Rick J. Jansen, Harry D. Bear. Early detection of racial disparity and treatment resistance 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 7664.

QSOX2 Upregulated in triple-negative breast cancer exacerbates patient prognosis by stabilizing integrin β1

Breast cancer (BC) remains a significant global health threat, with triple-negative breast cancer (TNBC) standing out as a particularly aggressive subtype lacking targeted therapies. Addressing this gap, we propose Quiescin Q6 sulfhydryl oxidase 2 (QSOX2) as a potential therapeutic target, a disulfide bond-forming enzyme implicated in cancer progression. Using publicly available datasets, we conducted a comprehensive analysis of QSOX2 expression in BC tumor and non-tumor tissues, assessing its specificity across different molecular subtypes. We further explored correlations between QSOX2 expression and patient outcomes, utilizing datasets like TCGA and METABRIC. In addition, we performed in vitro experiments to evaluate QSOX2 expression in BC cell lines and investigate the effects of QSOX2 knockdown on various TNBC cellular processes, including cell proliferation, apoptosis resistance, migration, and the epithelial-to-mesenchymal transition (EMT). Our results reveal significantly elevated QSOX2 expression in BC tumor tissues, particularly in TNBC, and establish an association between high QSOX2 expression and increased patient mortality, cancer progression, and recurrence across various BC subtypes. Notably, QSOX2 knockdown in TNBC cell lines reduces cell proliferation, enhances apoptosis, and suppresses migration, potentially mediated through its influence on the EMT process. Furthermore, we identify a significant link between QSOX2 and integrin β1 (ITGB1), suggesting that QSOX2 enhances ITGB1 stability, subsequently exacerbating the malignancy of TNBC. In conclusion, elevated QSOX2 expression emerges as a key factor associated with adverse patient outcomes in BC, particularly in TNBC, contributing to disease progression through various mechanisms, including the modulation of ITGB1 stability. Our findings underscore the potential of targeting QSOX2 as a therapeutic strategy for improving patient prognoses not only in TNBC but also in other BC subtypes.

SBF2-AS1 and TreRNA: novel lncRNA players in triple-negative breast cancer pathogenesis.

Compared to other breast cancer subtypes, triple-negative breast cancer (TNBC) has always been challenging for clinicians due to its aggressive behavior and lack of a specific treatment. There is a confirmed association between invasive features of tumors and increased epithelial-mesenchymal transition (EMT) process, which is consistent with a higher rate of EMT in TNBC. We investigated the expression of EMT-related genes, SNAI1 and MMP7, and EMT-related lncRNAs, treRNA and SBF2-AS1, in 50 TNBC tumors and 50 non-TNBC tumors to reveal more regulators and effectors involved in TNBC malignancy. In the present study, we showed the overexpression of all the studied genes and lncRNAs in TNBC tumors compared to non-TNBC samples. Moreover, a significant association was observed between MMP7 and treRNA expression levels and larger tumor size. A positive correlation between SNAI1 and lncRNA treRNA expression levels was also detected. Due to the differential expression and the potential diagnostic power of the studied genes, SBF2-AS1 and treRNA can be proposed as new probable biomarkers and therapeutic targets in TNBC.

Sialyl LewisX/A and Cytokeratin Crosstalk in Triple Negative Breast Cancer.

Triple-negative breast cancer (TNBC) encompasses multiple entities and is generally highly aggressive and metastatic. We aimed to determine the clinical and biological relevance of Sialyl-Lewis X and A (sLeX/A)-a fucosylated glycan involved in metastasis-in TNBC. Here, we studied tissues from 50 TNBC patients, transcripts from a TNBC dataset from The Cancer Genome Atlas (TCGA) database, and a primary breast cancer cell line. All 50 TNBC tissue samples analysed expressed sLeX/A. Patients with high expression of sLeX/A had 3 years less disease-free survival than patients with lower expression. In tissue, sLeX/A negatively correlated with cytokeratins 5/6 (CK5/6, which was corroborated by the inverse correlation between fucosyltransferases and CK5/6 genes. Our observations were confirmed in vitro when inhibition of sLeX/A remarkably increased expression of CK5/6, followed by a decreased proliferation and invasion capacity. Among the reported glycoproteins bearing sLeX/A and based on the STRING tool, α6 integrin showed the highest interaction score with CK5/6. This is the first report on the sLeX/A expression in TNBC, highlighting its association with lower disease-free survival and its inverse crosstalk with CK5/6 with α6 integrin as a mediator. All in all, sLeX/A is critical for TNBC malignancy and a potential prognosis biomarker and therapeutic target.

Dissection of FOXO1-Induced LYPLAL1-DT Impeding Triple-Negative Breast Cancer Progression via Mediating hnRNPK/β-Catenin Complex.

Triple-negative breast cancer (TNBC) is considered as the most hazardous subtype of breast cancer owing to its accelerated progression, enormous metastatic potential, and refractoriness to standard treatments. Long noncoding RNAs (lncRNAs) are extremely intricate in tumorigenesis and cancerous metastasis. Nonetheless, their roles in the initiation and augmentation of TNBC remain elusive. Here, in silico analysis and validation experiments were utilized to analyze the expression pattern of clinically effective lncRNAs in TNBC, among which a protective lncRNA LYPLAL1-DT was essentially curbed in TNBC samples and indicated a favorable prognosis. Gain- and loss-of-function assays elucidated that LYPLAL1-DT considerably attenuated the proliferative and metastatic properties along with epithelial-mesenchymal transition of TNBC cells. Moreover, forkhead box O1 (FOXO1) was validated to modulate the transcription of LYPLAL1-DT. Mechanistically, LYPLAL1-DT impinged on the malignancy of TNBC mainly by restraining the aberrant reactivation of the Wnt/β-catenin signaling pathway, explicitly destabilizing and diminishing β-catenin protein by interacting with heterogeneous nuclear ribonucleoprotein K (hnRNPK) and constricting the formation of the hnRNPK/β-catenin complex. Conclusively, our present research revealed the anti-oncogenic effects of LYPLAL1-DT in TNBC, unraveling the molecular mechanisms of the FOXO1/LYPLAL1-DT/hnRNPK/β-catenin signaling axis, which shed innovative light on the potential curative medicine of TNBC.

Andrographolide suppresses the malignancy of triple-negative breast cancer by reducing THOC1-promoted cancer stem cell characteristics

Triple-negative breast cancers (TNBCs) are difficult to cure and currently lack of effective treatment strategies. Cancer stem cells (CSCs) are highly associated with the poor clinical outcome of TNBCs. Thoc1 is a core component of the THO complex (THOC) that regulates the elongation, processing and nuclear export of mRNA. The function of thoc1 in TNBC and whether Thoc1 serves as a drug target are poorly understood. In this study, we demonstrated that thoc1 expression is elevated in TNBC cell lines and human TNBC patient tissues. Knockdown of thoc1 decreased cancer stem cell populations, reduced mammosphere formation, impaired THOC function, and downregulated the expression of stemness-related proteins. Moreover, the thoc1-knockdown 4T1 cells showed less lung metastasis in an orthotopic breast cancer mouse model. Overexpression of Thoc1 promoted TNBC malignancy and the mRNA export of stemness-related genes. Furthermore, treatment of TNBC cells with the natural compound andrographolide reduced the expression of Thoc1 expression, impaired homeostasis of THOC, suppressed CSC properties, and delayed tumor growth in a 4T1-implanted orthotopic mouse model. Andrographolide also reduced the activity of NF-κB, an upstream transcriptional regulator of Thoc1. Notably, thoc1 overexpression attenuates andrographolide-suppressed cellular proliferation. Altogether, our results demonstrate that THOC1 promotes cancer stem cell characteristics of TNBC, and andrographolide is a potential natural compound for eliminating CSCs of TNBCs by downregulating the NF-κB-thoc1 axis.

Racial and Ethnic Inequality in Survival Outcomes of Women With Triple Negative Breast Cancer.

PurposeTriple-negative breast cancer (TNBC) is the most lethal group of breast cancers. Socioeconomic factors may contribute to differences in survival rates. This study aims to identify racial/ethnic disparities in five-year survival rates among women affected by TNBC in the United States.MethodsThis retrospective study analyzed data from the 2010-2016 Surveillance, Epidemiology, and End Results Program database. Patients with a primary malignancy of triple-negative breast cancer were included in this study. Cancer-specific survival was measured at five years post-diagnosis. Cox regression models were used to calculate hazard ratios (HR) and corresponding 95% confidence intervals (CI).ResultsFrom 2010-2016, there were 26,963 women with a primary diagnosis of TNBC. After adjustment for age, insurance, marital status, stage, and surgery type, Hispanic women had the highest hazard of death when compared to White women (adjusted (adj) HR, 1.14, p<0.001). Further, non-Hispanic Black women also had a lower survival probability when compared to White women (adj HR, 1.06, p=0.002).ConclusionThis study reveals that Hispanic women had the highest hazard of death when compared to White women. As TNBC is the most fatal breast cancer, future studies should investigate socioeconomic factors that may worsen prognosis of this disease.

Upregulated GATA3/miR205-5p Axis Inhibits MFNG Transcription and Reduces the Malignancy of Triple-Negative Breast Cancer.

Simple SummaryTriple-negative cancer (TNBC) is a deadly disease that presents a potential health threat to women worldwide. It is the most aggressive and presents a poor prognosis among all breast cancer subgroups. We previously demonstrated that the elevated expression of manic fringe (MFNG) plays a pivotal role in breast cancer. However, the mechanism through which MFNG is regulated remains obscure. The study presented here set out to determine the mechanism by which MFNG expression is regulated in TNBC. Our findings revealed that GATA3 and miR-205-p cooperatively block the transcription of MFNG leading to the inhibition of cell migration and tumor growth in vitro and in vivo. Our study uncovers a novel GATA3/miR-205-p/MFNG feed-forward loop and miR205-5p could be adopted as a potential therapeutic strategy of TNBC.Triple-negative breast cancer (TNBC) accounts for approximately 20% of all breast carcinomas and has the worst prognosis of all breast cancer subtypes due to the lack of an effective target. Therefore, understanding the molecular mechanism underpinning TNBC progression could explore a new target for therapy. While the Notch pathway is critical in the development process, its dysregulation leads to TNBC initiation. Previously, we found that manic fringe (MFNG) activates the Notch signaling and induces breast cancer progression. However, the underlying molecular mechanism of MFNG upstream remains unknown. In this study, we explore the regulatory mechanisms of MFNG in TNBC. We show that the increased expression of MFNG in TNBC is associated with poor clinical prognosis and significantly promotes cell growth and migration, as well as Notch signaling activation. The mechanistic studies reveal that MFNG is a direct target of GATA3 and miR205-5p and demonstrate that GATA3 and miR205-5p overexpression attenuate MFNG oncogenic effects, while GATA3 knockdown mimics MFNG phenotype to promote TNBC progression. Moreover, we illustrate that GATA3 is required for miR205-5p activation to inhibit MFNG transcription by binding to the 3′ UTR region of its mRNA, which forms the GATA3/miR205-5p/MFNG feed-forward loop. Additionally, our in vivo data show that the miR205-5p mimic combined with polyetherimide-black phosphorus (PEI-BP) nanoparticle remarkably inhibits the growth of TNBC-derived tumors which lack GATA3 expression. Collectively, our study uncovers a novel GATA3/miR205-5p/MFNG feed-forward loop as a pathway that could be a potential therapeutic target for TNBC.

LncRNA LINC01315 promotes malignancy of triple-negative breast cancer and predicts poor outcomes by modulating microRNA-876-5p/GRK5

ABSTRACT Triple-negative breast cancer (TNBC) is a malignant tumor that threatens women’s health. Exploring novel development-associated biomarkers could help improve the survival rate of TNBC. This study evaluated the significance and mechanism of LINC01315 in TNBC progression aiming to identify a potential biomarker. There were 103 TNBC patients that provided clinical tissues in this study. The expression of LINC01315 was assessed by PCR and its association with clinical data was evaluated by statistical analyses. The in vitro cell experiments were conducted to estimate the biological effect of LINC01315 and its molecular mechanism. A significant upregulation of LINC01315 was observed in TNBC, which was associated with disease development and severity of patients. The upregulation of LINC01315 could be a symptom of the poor prognosis of patients. The knockdown of LINC01315 suppressed the main cellular processes of TNBC progression. Additionally, miR-876-5p was demonstrated to be a target of LINC01315 and regulate the expression of GRK5, through which LINC01315 modulated the progression of TNBC. Upregulated LINC01315 in TNBC indicated the malignant development and poor survival rate of patients. Inhibition of LINC01315 might be a potential therapeutic strategy of TNBC.

A conjugated 2D covalent organic framework as a drug delivery vehicle towards triple negative breast cancer malignancy

Cancer, one of the deadliest diseases for both sexes, has always demanded updated treatment strategies with time. Breast cancer is responsible for the highest mortality rate among females worldwide and requires treatment with advanced regimens due to the higher probability of breast cancer cells to develop drug cytotoxicity followed by resistance. Covalent organic framework (COF) materials with ordered nanoscale porosity can serve as drug delivery vehicles due to their biocompatible nature and large internal void spaces. In this research work, we have employed a novel biocompatible COF, TRIPTA, as a drug delivery carrier towards breast cancer cells. It served as a drug delivery vehicle for cisplatin in triple negative breast cancer (TNBC) cells. We have checked the potency of TRIPTA in combating the proliferation of metastatic TNBC cells. Our results revealed that cisplatin loaded over TRIPTA-COF exhibited a greater impact on the CD44+/CD24− cancer stem cell niche of breast cancer. Retarded migration of cancer cells has also been observed with the dual treatment of TRIPTA and cisplatin compared to that of cisplatin alone. Epithelial–mesenchymal transition (EMT) has also been minimized by the combinatorial treatment of cisplatin carried by the carrier material in comparison to cisplatin alone. The epithelial marker E-cadherin is significantly increased in cells treated with cisplatin together with the carrier COF, and the expression of mesenchymal markers such as N-cadherin is lower. The transcriptional factor Snail has been observed under the same treatment. The carrier material is also internalized by the cancer cells in a time-dependent manner, suggesting that the organic carrier can serve as a specific drug delivery vehicle. Our experimental results suggested that TRIPTA-COF can serve as a potent nanocarrier for cisplatin, showing higher detrimental effects on the proliferation and migration of TNBC cells by increasing the cytotoxicity of cisplatin.

Harnessing DNA Repair Defects to Augment Immune-Based Therapies in Triple-Negative Breast Cancer.

Triple-negative breast cancer (TNBC) has poor prognosis with limited treatment options, with little therapeutic progress made during the past several decades. DNA damage response (DDR) associated therapies, including radiation and inhibitors of DDR, demonstrate potential efficacy against TNBC, especially under the guidance of genomic subtype-directed treatment. The tumor immune microenvironment also contributes greatly to TNBC malignancy and response to conventional and targeted therapies. Immunotherapy represents a developing trend in targeted therapies directed against TNBC and strategies combining immunotherapy and modulators of the DDR pathways are being pursued. There is increasing understanding of the potential interplay between DDR pathways and immune-associated signaling. As such, the question of how we treat TNBC regarding novel immuno-molecular strategies is continually evolving. In this review, we explore the current and upcoming treatment options of TNBC in the context of DNA repair mechanisms and immune-based therapies, with a focus on implications of recent genomic analyses and clinical trial findings.

Formononetin relieves the facilitating effect of lncRNA AFAP1-AS1-miR-195/miR-545 axis on progression and chemo-resistance of triple-negative breast cancer.

This investigation attempted to discern whether formononetin restrained progression of triple-negative breast cancer (TNBC) by blocking lncRNA AFAP1-AS1-miR-195/miR-545 axis. We prepared TNBC cell lines (i.e. MDA-MB-231 and BT-549) and normal human mammary epithelial cell line (i.e. MCF-10A) in advance, and the TNBC cell lines were, respectively, transfected by pcDNA3.1-lncRNA AFAP1-AS1, si-lncRNA AFAP1-AS1, pcDNA6.2/GW/EmGFP-miR-545 or pcDNA6.2/GW/EmGFP-miR-195. Resistance of TNBC cells in response to 5-Fu, adriamycin, paclitaxel and cisplatin was evaluated through MTT assay, while potentials of TNBC cells in proliferation, migration and invasion were assessed via CCK8 assay and Transwell assay. Consequently, silencing of lncRNA AFAP1-AS1 impaired chemo-resistance, proliferation, migration and invasion of TNBC cells (P<0.05), and over-expression of miR-195 and miR-545, which were sponged and down-regulated by lncRNA AFAP1-AS1 (P<0.05), significantly reversed the promoting effect of pcDNA3.1-lncRNA AFAP1-AS1 on proliferation, migration, invasion and chemo-resistance of TNBC cells (P<0.05). Furthermore, CDK4 and Raf-1, essential biomarkers of TNBC progression, were, respectively, subjected to target and down-regulation of miR-545 and miR-195 (P<0.05), and they were promoted by pcDNA3.1-lncRNA AFAP1-AS1 at protein and mRNA levels (P<0.05). Additionally, formononetin significantly decreased expressions of lncRNA AFAP1-AS1, CDK4 and Raf-1, while raised miR-195 and miR-545 expressions in TNBC cells (P<0.05), and exposure to it dramatically contained malignant behaviors of TNBC cells (P<0.05). In conclusion, formononetin alleviated TNBC malignancy by suppressing lncRNA AFAP1-AS1-miR-195/miR-545 axis, suggesting that molecular targets combined with traditional Chinese medicine could yield significant clinical benefits in TNBC.

The lncRNA ADAMTS9-AS2 Regulates RPL22 to Modulate TNBC Progression via Controlling the TGF-β Signaling Pathway

BackgroundLong non-coding RNAs (lncRNAs) are key regulators of triple-negative breast cancer (TNBC) progression, but further work is needed to fully understand the functional relevance of these non-coding RNAs in this cancer type. Herein, we explored the functional role of the lncRNA ADAMTS9-AS2 in TNBC.MethodsNext-generation sequencing was conducted to compare the expression of different lncRNAs in TNBC tumor and paracancerous tissues, after which ADAMTS9-AS2differential expression in these tumor tissues was evaluated via qPCR. The functional role of this lncRNA was assessed by overexpressing it in vitro and in vivo. FISH and PCR were used to assess the localization of ADAMTS9-AS2within cells. Downstream targets of ADAMTS9-AS2 signaling were identified via RNA pulldown assays and transcriptomic sequencing.ResultsThe expression ofADAMTS9-AS2 was decreased in TNBC tumor samples (P < 0.05), with such downregulation being correlated with TNM stage, age, and tumor size. Overexpressing ADAMTS9-AS2 promoted the apoptotic death and cell cycle arrest of tumor cells in vitro and inhibited tumor growth in vivo. From a mechanistic perspective, ADAMTS9-AS2 was found to control the expression of RPL22 and to thereby modulate TGF-β signaling to control TNBC progression.ConclusionADAMTS9-AS2 controls the expression of RPL22 and thereby regulates TNBC malignancy via the TGF-β signaling pathway.

Triple-negative breast cancer therapeutic resistance: Where is the Achilles' heel?

Triple-negative breast cancer (TNBC) shows a higher response rate to systemic therapy compared with other breast cancer subtypes. However, the tumor differentiation of TNBC is poorer, with an early tendency to metastasis and a higher recurrence rate. Relapsed and metastatic TNBCs usually progress more rapidly, showing strong resistance to chemotherapy and radiotherapy. Due to the lack of combinatorial targeted drugs, alternative treatments fail to improve these patient's prognosis and the quality of life. Finding the Achilles' heel of TNBC is critical for patients with advanced TNBC. Here, we summarize the latest advances in the mechanisms underlying TNBC therapeutic resistance, consider how these mechanisms may affect the development and utilization of TNBC targeted drugs, and discuss the rationale of relevant signals as therapeutic targets. Also, we review the clinical trials registered in ClinicalTrial.gov for TNBC patients, which comprehensively reveals current research and development of novel TNBC targeted drugs and future trends.

2-Methoxy-5((3,4,5-trimethosyphenyl)seleninyl) phenol (SQ) inhibits cancer cell metastasis behavior of TNBC via suppressing EMT and VEGF

Triple-negative breast cancer (TNBC) is highly metastatic and lacks effective therapeutic targets among several subtypes of breast cancer. Cancer metastasis promotes the malignancy of TNBC and is closely related to the poor prognosis of the TNBC patients. We aim to explore novel agents that effectively inhibit cancer metastasis to treat TNBC. In our study, 2-Methoxy-5((3,4,5-trimethosyphenyl)seleninyl) phenol (SQ), a CA-4 analogue, could inhibit cell motility and invasion in MDA-MB-231 cells, and the mechanism is closely associated to the inhibition of epithelial-to-mesenchymal transition (EMT). Meanwhile, SQ significantly inhibited the expression and secretion of vascular endothelial growth factor (VEGF) in MDA-MB-231 cells. Moreover, the conditioned medium from SQ-treated MDA-MB-231 cells significantly inhibited the motility and invasion of human umbilical vein endothelial cells (HUVECs), which was correlated with the inhibition of EMT process in HUVECs. In addition, exogenous application of VEGF reversed the occurrence of EMT in HUVECs which stimulated by conditioned medium from SQ-treated cells. Furthermore, SQ inhibited vasculogenic mimicry (VM) formation in MDA-MB-231 cells, which was associated with VE-cadherin and EphA2 down-regulation. This study indicates that SQ inhibits MDA-MB-231 cell metastasis through suppressing EMT and VEGF, thereby implicating this compound might be a potential therapeutic agent against metastatic TNBC.

Inhibition of LIPG phospholipase activity suppresses tumor formation of human basal-like triple-negative breast cancer

The endothelial lipase LIPG possesses serine phospholipase activity and is involved in lipoprotein metabolism. Our previous studies have revealed that LIPG overexpression is required for tumor formation and metastasis of human basal-like triple-negative breast cancer (TNBC). We also demonstrated that LIPG differentially regulates TNBC malignancy through its enzymatic and non-enzymatic functions. The present studies were aimed at determining how XEN445, a specific inhibitor targeting LIPG phospholipase activity, impacts on TNBC tumor formation and malignant features. We established a cell-based LIPG enzymatic assay system to measure the inhibitory effect of XEN445 on LIPG phospholipase activity and determine its IC50. We found that XEN445 preferentially inhibited the proliferation of LIPG-expressing TNBC cells but not LIPG-negative luminal breast cancer cells. XEN445 inhibited the self-renewal of cancer stem cells (CSCs) in vitro and TNBC tumor formation in vivo. However, XEN445 had no inhibitory effect on the invasiveness and CSC stemness of TNBC cells. Our studies suggest that targeting both LIPG enzymatic and non-enzymatic functions is an important strategy for the treatment of TNBC.