Proliferation Of Triple Negative Breast Cancer Research Articles

Discovery of NO Donor-Aurovertin Hybrids as Dual Ferroptosis and Apoptosis Inducers for Treating Triple Negative Breast Cancer.

Triple-negative breast cancer (TNBC) is a highly lethal malignancy, and its clinical management encounters severe challenges due to its high metastatic propensity and the absence of effective therapeutic targets. To improve druggability of aurovertin B (AVB), a natural polyketide with a significant antiproliferative effect on TNBC, a series of NO donor/AVB hybrids were synthesized and tested for bioactivities. Among them, compound 4d significantly inhibited the proliferation and metastasis of TNBC in vitro and in vivo with better safety than that of AVB. The structure-activity relationship analysis suggested that the types of NO donor and the linkers had considerable effects on the activities. Mechanistic investigations unveiled that 4d induced apoptosis and ferroptosis by the reduction of mitochondrial membrane potential and the down-regulation of GPX4, respectively. The antimetastatic effect of 4d was associated with the upregulation of DUSP1. Overall, these compelling results underscore the tremendous potential of 4d for treating TNBC.

Combination of monensin and erlotinib synergistically inhibited the growth and cancer stem cell properties of triple-negative breast cancer by simultaneously inhibiting EGFR and PI3K signaling pathways.

Cancer stem cells (CSCs) in triple-negative breast cancer (TNBC) are recognized as a highly challenging subset of cells, renowned for their heightened propensity for relapse and unfavorable prognosis. Monensin, an ionophoric antibiotic, has been reported to exhibit significant therapeutic efficacy against various cancers, especially CSCs. Erlotinib is classified as one of the EGFR-TKIs and has been previously identified as a promising therapeutic target for TNBC. Our research aims to assess the effectiveness of combination of monensin and erlotinib as a potential treatment strategy for TNBC. The combination of monensin and erlotinib was assessed for its potential anticancer activity through various in vitro assays, including cytotoxicity assay, colony formation assay, wound healing assay, transwell assay, mammosphere formation assay, and proportion of CSCs assay. Additionally, an in vivo study using tumor-bearing nude mice was conducted to evaluate the inhibitory effect of the monensin and erlotinib combination on tumor growth. The results indicated that combination of monensin with erlotinib synergistically inhibited cell proliferation, the migration rate, the invasion ability and decreased the CSCs proportion, and CSC markers SOX2 and CD133 in vivo and in vitro. Furthermore, the primary proteins involved in the signaling pathways of the EGFR/ERK and PI3K/AKT are simultaneously inhibited by the combination treatment of monensin and erlotinib in vivo and in vitro. The simultaneous inhibition of the EGFR/ERK and PI3K/AKT/mTOR signaling pathways by the combination of monensin and erlotinib exhibited a synergistic effect on suppressing tumor proliferation and cancer cell stemness in TNBC.

KMT2D-mediated H3K4me1 recruits YBX1 to facilitate triple-negative breast cancer progression through epigenetic activation of c-Myc.

Lysine methyltransferase 2D (KMT2D) mediates mono-methylation of histone H3 lysine 4 (H3K4me1) in mammals. H3K4me1 mark is involved in establishing an active chromatin structure to promote gene transcription. However, the precise molecular mechanism underlying the KMT2D-mediated H3K4me1 mark modulates gene expression in triple-negative breast cancer (TNBC) progression is unresolved. We recognized Y-box-binding protein 1 (YBX1) as a "reader" of the H3K4me1 mark, and a point mutation of YBX1 (E121A) disrupted this interaction. We found that KMT2D and YBX1 cooperatively promoted cell growth and metastasis of TNBC cells in vitro and in vivo. The expression levels of KMT2D and YBX1 were both upregulated in tumour tissues and correlated with poor prognosis for breast cancer patients. Combined analyses of ChIP-seq and RNA-seq data indicated that YBX1 was co-localized with KMT2D-mediated H3K4me1 in the promoter regions of c-Myc and SENP1, thereby activating their expressions in TNBC cells. Moreover, we demonstrated that YBX1 activated the expressions of c-Myc and SENP1 in a KMT2D-dependent manner. Our results suggest that KMT2D-mediated H3K4me1 recruits YBX1 to facilitate TNBC progression through epigenetic activation of c-Myc and SENP1. These results together unveil a crucial interplay between histone mark and gene regulation in TNBC progression, thus providing novel insights into targeting the KMT2D-H3K4me1-YBX1 axis for TNBC treatment. YBX1 is a KMT2D-mediated H3K4me1-binding effector protein and mutation of YBX1 (E121A) disrupts its binding to H3K4me1. KMT2D and YBX1 cooperatively promote TNBC proliferation and metastasis by activating c-Myc and SENP1 expression in vitro and in vivo. YBX1 is colocalized with H3K4me1 in the c-Myc and SENP1 promoter regions in TNBC cells and increased YBX1 expression predicts a poor prognosis in breast cancer patients.

Harnessing adrenergic blockade in stress-promoted TNBC in vitro and solid tumor in vivo: disrupting HIF-1α and GSK-3β/β-catenin driven resistance to doxorubicin.

Sympathetic activation triggered by chronic stress afflicting cancer survivors is an emerging modulator of tumorigenesis. Adrenergic blockade was previously associated with improving response to doxorubicin (DOX) in triple-negative breast cancer (TNBC), yet the precise underlying mechanisms remain obscure. The resilience of cancer stem cells (CSCs) during chemotherapy fosters resistance and relapse. Hypoxia-inducible factor-1α (HIF-1α) and β-catenin are intertwined transcriptional factors that enrich CSCs and evidence suggests that their expression could be modulated by systemic adrenergic signals. Herein, we aimed to explore the impact of adrenoreceptor blockade using carvedilol (CAR) on DOX and its potential to modulate CSCs overcoming chemoresistance. To achieve this aim, in vitro studies were conducted using adrenaline-preincubated MDA-MB-231 cells and in vivo studies using a chronic restraint stress-promoted solid tumor mouse model. Results revealed that adrenaline increased TNBC proliferation and induced a phenotypic switch reminiscent of CSCs, as evidenced by enhanced mammosphere formation. These results paralleled an increase in aldehyde dehydrogenase-1 (ALDH-1) and Nanog expression levels as well as HIF-1α and β-catenin upsurge. In vivo, larger tumor volumes were observed in mice under chronic stress compared to their unstressed counterparts. Adrenergic blockade using CAR, however, enhanced the impact DOX had on halting TNBC cell proliferation and tumor growth via enhanced apoptosis. CAR also curbed HIF-1α and β-catenin tumor levels subsequently suppressing ALDH-1 and SOX2. Our study unveils a central role for HIF-1α linking stress-induced sympathetic activation fueling CSC enrichment via the β-catenin pathway. It also highlights novel insights into CAR's capacity in reversing DOX chemoresistance in TNBC.

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.

The DRAP1/DR1 Repressor Complex Increases mTOR Activity to Promote Progression and Confer Everolimus Sensitivity in Triple-Negative Breast Cancer.

Triple-negative breast cancer (TNBC) is the most aggressive subtype of breast cancer. Transcriptional dysregulation is a hallmark of cancer, and several transcriptional regulators have been demonstrated to contribute to cancer progression. Here, we identified upregulation of the transcriptional corepressor DRAP1 in TNBC, which was closely associated with poor recurrence-free survival in TNBC patients. DRAP1 promoted TNBC proliferation, migration, and invasion in vitro and tumor growth and metastasis in vivo. Mechanistically, the DR1/DRAP1 heterodimer complex inhibited expression of the arginine sensor CASTOR1 and thereby increased activation of mTOR, which sensitized TNBC to treatment with the mTOR inhibitor everolimus. DRAP1 and DR1 also formed a positive feedback loop. DRAP1 enhanced the stability of DR1, recruiting the deubiquitinase USP7 to inhibit its proteasomal degradation; in turn, DR1 directly promoted DRAP1 transcription. Collectively, this study uncovered a DRAP1-DR1 bidirectional regulatory pathway that promotes TNBC progression, suggesting that targeting the DRAP1/DR1 complex might be a potential therapeutic strategy to treat TNBC.

Abstract PO4-28-07: SLC26A9 promotes triple-negative breast cancer progression by regulating lipid metabolism

Abstract Background: The disturbance of lipid metabolism in the microenvironment plays an important role in the occurrence and development of triple-negative breast cancer(TNBC). SLC26A9, a member of the SLC26A family of anion transporters, is involved in breast oncogenesis. However, the effect of SLC26A9 in triple-negative breast cancer on lipid metabolism in the tumor microenvironment remains unclear. Methods: Bioinformatics, tissue microarrays and TNBC cell lines were used to detect the expression of SLC26A9 and its clinical significance. By altering the expression of SLC26A9 gene in TNBC cells, the effects of SLC26A9 on the regulation of lipid metabolism, cell biological behavior and its related molecular mechanisms in the TNBC microenvironment were explored using adoptive staining techniques, flow cytometric analysis and animal models. Results: We found by tissue microarray (TNBC=105 cases, Nor=67 cases) that the expression of SLC26A9 was significantly up-regulated in BC compared to paracancerous tissues, where SLC26A9 expression was higher in TNBC, and the same results were obtained in BC cell lines. Secondly, we found that SCL26A9 was positively correlated with lipid metabolism status in TNBC microenvironment and possessed a close association with P53 mutation by analyzing GEO and TCGA databases. Therefore, we used two cell lines (MDA-MB-231, MDA-MB-468) in which SCL26A9 was highly expressed in TNBC cell lines. It was demonstrated by oil red O staining and lipid fluorescence staining that knockdown/silencing of SLC26A9 diminished the ability of MDA-MB-231 and MDA-MB-468 cells to uptake and utilize lipids, especially for metabolites such as neutral lipids: triglycerides, lipid droplets, and steroidal substances. Then we demonstrated by using fatty acid flow cytometric analysis that knockdown/silencing of SLC26A9 significantly reduced the utilization and production of fatty acids in MDA-MB-231 and MDA-MB-468 cells, which are the key metabolic indicators of cancer cells as well as important energy-providing substances for cancer progression. Therefore, we further verified functionally that cell proliferation, migration, invasion and anti-apoptosis were significantly inhibited in in vitro after knockdown/silencing of SLC26A9, and in vivo tumorigenesis was significantly inhibited in BALB/c nude mice in in vivo. In addition, the expression of markers of lipid metabolic activity (FASN, ACLY) was reduced after knockdown/silencing of SLC26A9 in MDA-MB-231 cells by Western Blot, and the reduced expression of FASN and ACLY mainly inhibited the ab initio synthesis, uptake and utilization of fatty acids in TNBC cells, which in turn regulated the proliferation and invasion of TNBC. Mechanistically, SLC26A9 silencing/knockdown inhibited the synthesis, uptake, and utilization of multiple metabolites of lipids in TNBC, which combined with the TCGA database results revealed the activation of the key signaling pathway, the JAK-STAT3 signaling pathway, to promote the progression of TNBC. Conclusion(s): SLC26A9 is involved in the disturbance of lipid metabolism in the TNBC microenvironment and regulates the progression of TNBC. The search for new SLC26A9 inhibitors is expected to provide a new direction for the treatment of TNBC, but the exact molecular mechanisms need to be further explored. SLC26A9 upregulation in TNBC leads to a poor prognosis by referencing lipid metabolism in the TNBC microenvironment Wench. SLC26A9 is involved in lipid metabolism disorders and cell biological functions in the TNBC microenvironment in vivo. SLC26A9 is involved in disordered lipid metabolism in the TNBC microenvironment. Citation Format: Yingming Zhou, Hu Wang, Zhengxing Zhou, Xuemei Liu, Biguang Tuo, Taolang Li. SLC26A9 promotes triple-negative breast cancer progression by regulating lipid metabolism [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 PO4-28-07.

The therapeutic potential of circular RNA in triple-negative breast cancer.

Triple-negative breast cancer (TNBC) is among the most aggressive subtypes of the disease that does not express estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2. Circular RNAs (circRNAs) are a type of non-coding RNA with a circular shape formed by non-standard splicing or reverse splicing. Numerous circRNAs exhibit abnormal expression in various malignancies, showing their critical role in the emergence and growth of tumors. Recent studies have shown evidence supporting the idea that certain circRNAs regulate the proliferation and metastasis of TNBC. In addition, circRNAs alter metabolism and the immune microenvironment to promote or inhibit the development of TNBC. Notably, circRNAs may affect the efficacy of clinical drug therapy, serve as therapeutic targets, and be used as molecular biomarkers in the future. Herein, we will first summarize the biogenesis and function of circRNAs. Then, we will explain current research on circRNAs related to TNBC and their potential to serve as therapeutic targets or biomarkers for future drug development, providing a new direction and idea for TNBC therapy.

Mitochondria-targeted ruthenium complexes can be generated in vitro and in living cells to target triple-negative breast cancer cells by autophagy inhibition

Triple-negative breast cancer (TNBC) is the most aggressive type of breast cancer, which owned severe resistance to platinum-based anticancer agents. Herein, we report a new metal-arene complex, Ru-TPE-PPh3, which can be synthesized in vitro and in living cells with copper catalyzed the cycloaddition reaction of Ru-azide and alkynyl (CuAAC). The complex Ru-TPE-PPh3 exhibited superior inhibition of the proliferation of TNBC MDA-MB-231 cells with an IC50 value of 4.0 μM. Ru-TPE-PPh3 could induce the over production of reactive oxygen species (ROS) to initiate the oxidative stress, and further damage the mitochondria both functionally and morphologically, as loss of mitochondrial membrane potential (MMP) and cutting the supply of adenosine triphosphate (ATP), the disappearance of cristae structure. Moreover, the damaged mitochondria evoked the occurrence of mitophagy with the autophagic flux blockage and cell death. The complex Ru-TPE-PPh3 also demonstrated excellent anti-proliferative activity in 3D MDA-MB-231 multicellular tumor spheroids (MCTSs), indicating the potential to inhibit solid tumors in living cells. This study not only provided a potent agent for the TNBC treatment, but also demonstrated the universality of the bioorthogonally catalyzed lethality (BCL) strategy through CuAAC reation.

YTHDC1-dependent m6A modification modulated FOXM1 promotes glycolysis and tumor progression through CENPA in triple-negative breast cancer.

Triple-negative breast cancer (TNBC) exhibits heightened aggressiveness compared with other breast cancer (BC) subtypes, with earlier relapse, a higher risk of distant metastasis, and a worse prognosis. Transcription factors play a pivotal role in various cancers. Here, we found that factor forkhead box M1 (FOXM1) expression was significantly higher in TNBC than in other BC subtypes and normal tissues. Combining the findings of Gene Ontology (GO) enrichment analysis and a series of experiments, we found that knockdown of the FOXM1 gene attenuated the ability of TNBC cells to proliferate and metastasize both invivo and invitro. In addition, Spearman's test showed that FOXM1 significantly correlated with glycolysis-related genes, especially centromere protein A (CENPA) in datasets (GSE76250, GSE76124, GSE206912, and GSE103091). The effect of silencing FOXM1 on the inhibition of CENPA expression, TNBC proliferation, migration, and glycolysis could be recovered by overexpression of CENPA. According to MeRIP, the level of m6A modification on FOMX1 decreased in cells treated with cycloleucine (a m6A inhibitor) compared with that in the control group. The increase in FOXM1 expression caused by YTHDC1 overexpression could be reversed by the m6A inhibitor, which indicated that YTHDC1 enhanced FOXM1 expression depending on m6A modification. Therefore, we concluded that the YTHDC1-m6A modification/FOXM1/CENPA axis plays an important role in TNBC progression and glycolysis.

Dissection of triple-negative breast cancer microenvironment and identification of potential therapeutic drugs using single-cell RNA sequencing analysis

Breast cancer remains a leading cause of mortality in women worldwide. Triple-negative breast cancer (TNBC) is a particularly aggressive subtype characterized by rapid progression, poor prognosis, and lack of clear therapeutic targets. In the clinic, delineation of tumor heterogeneity and development of effective drugs continue to pose considerable challenges. Within the scope of our study, high heterogeneity inherent to breast cancer was uncovered based on the landscape constructed from both tumor and healthy breast tissue samples. Notably, TNBC exhibited significant specificity regarding cell proliferation, differentiation, and disease progression. Significant associations between tumor grade, prognosis, and TNBC oncogenes were established via pseudotime trajectory analysis. Consequently, we further performed comprehensive characterization of the TNBC microenvironment. A crucial epithelial subcluster, E8, was identified as highly malignant and strongly associated with tumor cell proliferation in TNBC. Additionally, epithelial-mesenchymal transition-associated fibroblast and M2 macrophage subclusters exerted an influence on E8 through cellular interactions, contributing to tumor growth. Characteristic genes in these three cluster cells could therefore serve as potential therapeutic targets for TNBC. The collective findings provided valuable insights that assisted in the screening of a series of therapeutic drugs, such as pelitinib. We further confirmed the anti-cancer effect of pelitinib in an orthotopic 4T1 tumor-bearing mouse model. Overall, our study sheds light on the unique characteristics of TNBC at single-cell resolution and the crucial cell types associated with tumor cell proliferation that may serve as potent tools in the development of effective anti-cancer drugs.

Advancing apoptosis induction in triple negative breast cancer: Empowering treatment with tyrosine-stapled mixed micelles of lapatinib

The available treatment modalities for triple-negative breast cancer (TNBC) face several challenges, including discouraging overall survival outcomes, unavoidable toxicities, and the emergence of drug resistance. Further, there is an amplified requirement for various amino acids to support the uncontrolled proliferation of TNBC. Hence, targeted therapy for enhancing the treatment of TNBC was explored which encompassed hydrophobized (using α-linolenic acid) Pluronic-based mixed micelles having inherent L-type/Large neutral amino acid transporter 1 targeting (tyrosine-stapled) ability (LPT T-MM). LPT T-MM had optimal size (142.34 ± 30.23 nm), polydispersity index (0.224 ± 0.01), and enhanced drug loading capacity (∼10 %). Transmission electron microscopy confirmed their spherical shape. In vitro release studies showed sustained drug release without hemolysis risk. LPT T-MM had higher cellular uptake and cytotoxicity than free LPT. IC50 values for LPT T-MM were significantly reduced in MDA-MB-231 (∼1.64-fold) and 4 T1 (∼1.88-fold) cell lines; apoptosis index was superior in MDA-MB-231 (∼2.04-fold) and 4 T1 cell line (∼2.09-fold) compared to free LPT. LPT T-MM generated more reactive oxygen species and caused mitochondrial membrane depolarization, indicating increased cell death by apoptosis. Thus, LPT T-MM had the ability to promote apoptosis, showed promise in enhancing the payload capabilities and targeting in TNBC.

Mammary tissue-derived extracellular matrix hydrogels reveal the role of irradiation in driving a pro-tumor and immunosuppressive microenvironment

Radiation therapy (RT) is essential for triple negative breast cancer (TNBC) treatment. However, patients with TNBC continue to experience recurrence after RT. The role of the extracellular matrix (ECM) of irradiated breast tissue in tumor recurrence is still unknown. In this study, we evaluated the structure, molecular composition, and mechanical properties of irradiated murine mammary fat pads (MFPs) and developed ECM hydrogels from decellularized tissues (dECM) to assess the effects of RT-induced ECM changes on breast cancer cell behavior. Irradiated MFPs were characterized by increased ECM deposition and fiber density compared to unirradiated controls, which may provide a platform for cell invasion and proliferation. ECM component changes in collagens I, IV, and VI, and fibronectin were observed following irradiation in both MFPs and dECM hydrogels. Encapsulated TNBC cell proliferation and invasive capacity was enhanced in irradiated dECM hydrogels. In addition, TNBC cells co-cultured with macrophages in irradiated dECM hydrogels induced M2 macrophage polarization and exhibited further increases in proliferation. Our study establishes that the ECM in radiation-damaged sites promotes TNBC invasion and proliferation as well as an immunosuppressive microenvironment. This work represents an important step toward elucidating how changes in the ECM after RT contribute to breast cancer recurrence.

CARM1 drives triple-negative breast cancer progression by coordinating with HIF1A.

Coactivator-associated arginine methyltransferase 1 (CARM1) promotes the development and metastasis of estrogen receptor alpha (ERα)-positive breast cancer. The function of CARM1 in triple-negative breast cancer (TNBC) is still unclear and requires further exploration. Here, we report that CARM1 promotes proliferation, epithelial-mesenchymal transition (EMT), and stemness in TNBC. CARM1 is upregulated in multiple cancers and its expression correlates with breast cancer progression. Genome-wide analysis of CARM1 showed that CARM1 is recruited by hypoxia-inducible factor 1 subunit alpha (HIF1A) and occupy the promoters of CDK4, Cyclin D1, β-catenin, HIF1A, MALAT1, and SIX1 critically involved in cell cycle, HIF-1 signaling pathway, Wnt signaling pathway, VEGF signaling pathway, thereby modulating the proliferation and invasion of TNBC cells. We demonstrated that CARM1 is physically associated with and directly interacts with HIF1A. Moreover, we found that ellagic acid, an inhibitor of CARM1, can suppress the proliferation and metastasis of TNBC by directly inhibiting CDK4 expression. Our research has determined the molecular basis of CARM1 carcinogenesis in TNBC and its effective natural inhibitor, which may provide new ideas and drugs for cancer therapy.

Isocitrate dehydrogenase 2 regulates the proliferation of triple-negative breast cancer through the ferroptosis pathway.

Triple-negative breast cancer (TNBC) is currently the type of breast cancer with the worst prognosis; it lacks specific treatments, such as ER/PR antagonistic endocrine and anti-HER2 targeted therapies. Although immunotherapy with immune checkpoints has shown some efficacy in many solid tumors, clinical data in TNBC suggest significant limitations. The essence of ferroptosis is the impaired metabolism of intracellular lipid oxides, which in turn causes the activation and abnormalities of the immune system, including ROS, and not only plays an important role in liver injury and organ aging but also a large amount of data points to the close correlation between the ferroptosis process and tumor development. In this study, through the analysis of large-throughput biological data of breast tumors, combined with the characteristics of the biological process of ferroptosis, the specific gene IDH2 was found to be significantly highly expressed in TNBC and functionally correlated with ferroptosis. Through clinical specimens validated at the gene and protein levels, in vitro tumor cell line validation, and in vivo mouse models, we found that the high expression of IDH2 in TNBC has a role in inhibiting the ferroptosis process in TNBC, thus promoting the proliferation of TNBC cells and other malignant features.

Role of β3 subunit of the GABA type A receptor in triple negative breast cancer proliferation, migration, and cell cycle progression

ABSTRACT Triple negative breast cancer (TNBC) is known for its heterogeneous nature and aggressive onset. The unresponsiveness to hormone therapies and immunotherapy and the toxicity of chemotherapeutics account for the limited treatment options for TNBC. Ion channels have emerged as possible therapeutic candidates for cancer therapy, but little is known about how ligand gated ion channels, specifically, GABA type A ligand-gated ion channel receptors (GABAAR), affect cancer pathogenesis. Our results show that the GABAA β3 subunit is expressed at higher levels in TNBC cell lines than non-tumorigenic cells, therefore contributing to the idea that limiting the GABAAR via knockdown of the GABAA β3 subunit is a potential strategy for decreasing the proliferation and migration of TNBC cells. We employed pharmacological and genetic approaches to investigate the role of the GABAA β3 subunit in TNBC proliferation, migration, and cell cycle progression. The results suggest that pharmacological antagonism or genetic knockdown of GABAA β3 subunit decreases TNBC proliferation and migration. In addition, GABAA β3 subunit knockdown causes cell cycle arrest in TNBC cell lines via decreased cyclin D1 and increased p21 expression. Our findings suggest that membrane bound GABAA receptors containing the β3 subunit can be further developed as a potential novel target for the treatment of TNBC.

Long-chain noncoding RNA LINC01569 upregulates filamin A-interacting protein 1-like to prevent metastasis of triple-negative breast cancer via sponging miR-300.

Long-chain noncoding RNA (lncRNA), LINC01569, is important for regulating the extracellular matrix, which affects cell migration. However, its involvement in the occurrence and development of triple-negative breast cancer (TNBC) remains unclear. This study is aimed to investigate the role of LINC01569 on TNBC. Online database was used for clinical data analysis. Cell viability and migration capability were monitored using cell counting kit-8 and transwell assays, respectively. Luciferase reporter assay and RNA pull-down were used to confirm the binding capability between noncoding RNAs and filamin A-interacting protein 1-like (FILIP1L). Western blotting was used to determine the protein content. Compared with normal breast tissue, LINC01569 was significantly reduced in patients with TNBC subtype, and LINC01569 expression gradually decreased with the progression of tumor stage. Patients with TNBC with high lncRNA LINC01569 levels had a better prognosis than did patients with low LINC01569 levels. LINC01569 overexpression inhibited the migration capability, whereas siRNA-mediated LINC01569 downregulation promoted the migration capability in TNBC cells. Using ENCORI and lncRNA SNP online databases, miR-300 was screened as the potential sponge of LINC01569. The binding of LINC01569 to miR-300 was confirmed using the dual-luciferase reporter and RNA pull-down assays. miR-300 was negatively correlated with LINC01569, and miR-300 mimics eliminated the anti-proliferation and anti-migration effects of LINC01569 on TNBC cells. Additionally, FILIP1L was further verified as the downstream target of miR-300. miR-300 mimics blocked LINC01569 upregulation-mediated elevation of FILIP1L. Importantly, the anti-tumor effects mediated by LINC01569 overexpression were abolished by miR-300 mimics and further restored by FILIP1L upregulation. LINC01569 was expressed at a low level in TNBC and could sponge miR-300 to promote FILIP1L expression, reducing the proliferation and metastasis capability of TNBC. Thus, LINC01569 might be a useful biomarker in the diagnosis and prognosis of metastatic TNBC.

Mechanism of Erianin anti-triple negative breast cancer based on transcriptomics methods and network pharmacology.

Triple negative breast cancer (TNBC) is a highly aggressive illness that lacks effective targeted treatments. Although Erianin has shown potential antitumor properties, its precise mechanism of action and target in TNBC remain unclear, hampering the development of drugs. The present study investigated the underlying mechanism of action of Erianin in treating TNBC by using transcriptomics and network pharmacology approaches. We evaluated Erianin's bioactivity in TNBC cell lines and xenograft tumor models. The results showed that Erianin significantly inhibited TNBC cell proliferation and impeded tumor growth. A subsequent analysis of transcriptomic and network pharmacological data identified 51 mutual targets. Analysis of protein-protein interactions identified eight hub targets. Furthermore, molecular docking indicated that the PPARA binding energy was the lowest for Erianin among the hub targets, followed by ROCK2, PDGFRB, CCND1, MUC1, and CDK1. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes functional enrichment analysis showed that the common targets were associated with multiple cancer-related signaling pathways, including focal adhesion, PI3K-Akt signaling pathway, Rap1 signaling pathway, microRNAs in cancer, and human papillomavirus infection. The results of the Western blot and immunohistochemistry experiment further showed that Erianin could suppress PI3K/Akt signaling pathway activation. After co-incubation with SC79, the cell inhibition rate of Erianin was decreased, which further confirmed that Erianin inhibits TNBC progression via the PI3K-AKT signaling pathway. In conclusion, our results indicated that Erianin has the potential to inhibit the proliferation of TNBC by downregulating the PI3K/AKT signaling pathway by transcriptomics and network pharmacology. Therefore, Erianin appears to be a promising compound for the effective treatment of TNBC.

Reciprocal regulation of forkhead box C1 and L1 cell adhesion molecule contributes to triple-negative breast cancer progression

PurposeThe potential of targeting forkhead box C1 (FOXC1) as a therapeutic approach for triple-negative breast cancer (TNBC) is promising. However, a comprehensive understanding of FOXC1 regulation, particularly upstream factors, remains elusive. Expression of the L1 cell adhesion molecule (L1CAM), a transmembrane glycoprotein associated with brain metastasis, was observed to be positively associated with FOXC1 transcripts. Thus, this study aims to investigate their relationship in TNBC progression.MethodsPublicly available FOXC1 and L1CAM transcriptomic data were obtained, and their corresponding proteins were analyzed in four TNBC cell lines. In BT549 cells, FOXC1 and L1CAM were individually silenced, while L1CAM was overexpressed in BT549-shFOXC1, MDA-MB-231, and HCC1937 cells. CCK-8, transwell, and wound healing assays were performed in these cell lines, and immunohistochemical staining was conducted in tumor samples.ResultsA positive correlation between L1CAM and FOXC1 transcripts was observed in publicly available datasets. In BT549 cells, knockdown of FOXC1 led to reduced L1CAM expression at both the transcriptional and protein levels, and conversely, silencing of L1CAM decreased FOXC1 protein levels, but interestingly, FOXC1 transcripts remained largely unaffected. Overexpressing L1CAM resulted in increased FOXC1 protein expression without significant changes in FOXC1 mRNA levels. This trend was also observed in BT549-shFOXC1, MDA-MB-231-L1CAM, and HCC1937-L1CAM cells. Notably, alterations in FOXC1 or L1CAM levels corresponded to changes in cell proliferation, migration, and invasion capacities. Furthermore, a positive correlation between L1CAM and FOXC1 protein expression was detected in human TNBC tumors.ConclusionFOXC1 and L1CAM exhibit co-regulation at the protein level, with FOXC1 regulating at the transcriptional level and L1CAM regulating at the post-transcriptional level, and together they positively influence cell proliferation, migration, and invasion in TNBC.

PIWI-interacting RNA-YBX1 inhibits proliferation and metastasis by the MAPK signaling pathway via YBX1 in triple-negative breast cancer

Breast cancer is the second leading cause of death in women worldwide, with triple-negative breast cancer (TNBC) having the worst prognosis. Although there are numerous studies on TNBC, there is no effective treatment for it, and it is still a major problem today. Studies on PIWI-interacting RNAs (piRNAs) are increasing and investigating the mechanism of piRNAs in the proliferation and metastasis of TNBC may lead to new potential treatment targets. Here, we identified a novel piRNA, piR-YBX1, which was downregulated in TNBC compared to matched normal breast tissue. Overexpression of piR-YBX1 significantly inhibited the proliferation, migration, invasion ability of TNBC cells both in vivo and in vitro. Mechanistically, piR-YBX1 could bind directly to mRNA of Y-box binding protein 1 (YBX1) and overexpression of piR-YBX1 downregulated YBX1 in both mRNA and protein levels, while the function of piR-YBX1 could be partly rescued by overexpression of YBX1. In addition, YBX1 could bind to RAF1 which is the key molecule in the MAPK signaling pathway, and overexpression of piR-YBX1 inhibited the p-MEK and p-ERK1/2, which can be reverted by YBX1. In conclusion, our findings discovered that the piR-YBX1/YBX1/MAPK axis suppresses the proliferation and metastasis of TNBC and therefore piR-YBX1 has the potential to be an effective therapeutic agent for breast cancer.