Triple-negative Breast Cancer Cell Proliferation Research Articles

CDK4 inactivation inhibits apoptosis via mitochondria-ER contact remodeling in triple-negative breast cancer

The energetic demands of proliferating cells during tumorigenesis require close coordination between the cell cycle and metabolism. While CDK4 is known for its role in cell proliferation, its metabolic function in cancer, particularly in triple-negative breast cancer (TNBC), remains unclear. Our study, using genetic and pharmacological approaches, reveals that CDK4 inactivation only modestly impacts TNBC cell proliferation and tumor formation. Notably, CDK4 depletion or long-term CDK4/6 inhibition confers resistance to apoptosis in TNBC cells. Mechanistically, CDK4 enhances mitochondria-endoplasmic reticulum contact (MERCs) formation, promoting mitochondrial fission and ER-mitochondrial calcium signaling, which are crucial for TNBC metabolic flexibility. Phosphoproteomic analysis identified CDK4’s role in regulating PKA activity at MERCs. In this work, we highlight CDK4’s role in mitochondrial apoptosis inhibition and suggest that targeting MERCs-associated metabolic shifts could enhance TNBC therapy.

Screening of a kinase inhibitor library identified novel targetable kinase pathways in triple-negative breast cancer.

Triple-negative breast cancer (TNBC) is a highly invasive breast cancer subtype that is challenging to treat due to inherent heterogeneity and absence of estrogen, progesterone, and human epidermal growth factor 2 receptors. Kinase signaling networks drive cancer growth and development, and kinase inhibitors are promising anti-cancer strategies in diverse cancer subtypes. Kinase inhibitor screens are an efficient, valuable means of identifying compounds that suppress cancer cell growth in vitro , facilitating the identification of kinase vulnerabilities to target therapeutically. The Kinase Chemogenomic Set is a well-annotated library of 187 kinase inhibitor compounds that indexes 215 kinases of the 518 in the known human kinome representing various kinase networks and signaling pathways, several of which are understudied. Our screen revealed 14 kinase inhibitor compounds effectively inhibited TNBC cell growth and proliferation. Upon further testing, three compounds, THZ531, THZ1, and PFE-PKIS 29, had the most significant and consistent effects across a range of TNBC cell lines. These cyclin-dependent kinase (CDK)12/CDK13, CDK7, and phosphoinositide 3-kinase inhibitors, respectively, decreased metabolic activity in TNBC cell lines and promote a gene expression profile consistent with the reversal of the epithelial-to-mesenchymal transition, indicating these kinase networks potentially mediate metastatic behavior. These data identified novel kinase targets and kinase signaling pathways that drive metastasis in TNBC.

The role of ABI2 in modulating nuclear proteins: Therapeutic implications for NUP54 and NUP153 in TNBC.

Triple-negative breast cancer (TNBC) is a highly aggressive subtype of breast cancer that lacks hormone receptors, which makes it more likely to metastasize and have a poor prognosis. Despite some effectiveness of chemotherapy, TNBC remains challenging to manage, with high relapse and mortality rates. Recent findings have highlighted the role of the ubiquitin-protease system in TNBC, with ABI2 identified as a significant regulator. Reduced ABI2 expression is associated with aggressive disease and poor outcomes, whereas ABI2 overexpression (OE-ABI2) inhibits TNBC cell proliferation by modulating the PI3K/Akt signaling pathway. Although ABI2 is not a nuclear protein, it influences critical nuclear functions such as DNA repair and gene expression. Nuclear proteins, particularly those in the nuclear pore complex and nuclear matrix, are essential for cellular functions and have been linked to various diseases, including cancer. This study used RNA sequencing (RNA-seq) to examine the gene expression in MDA-MB-231 cell line and ABI2-overexpressing cells. Differentially expressed genes were annotated, and a protein-protein interaction network was constructed. Network and enrichment analysis identified the nucleoporins NUP54 and NUP153 as potential novel targets for TNBC. This study emphasizes the impact of ABI2 on nuclear proteins and suggests that targeting NUP54 and NUP153 could offer new therapeutic options for TNBC.

Inhibition of triple-negative breast cancer growth via delphinidin-mediated suppression of the JAK2/STAT3/PD-L1 pathway.

Breast cancer is a leading cause of cancer-related mortality among women globally, with triple-negative breast cancer (TNBC) being particularly aggressive. Delphinidin (Dp), an anthocyanin monomer, has shown promising health benefits. This study investigates the effects of Dp on TNBC and aims to elucidate its specific mechanisms of action. We utilized cell counting kit-8 (CCK-8) assays, colony formation assays, and scratch assays to evaluate the influence of Dp on the proliferation and migration of TNBC cells. Flow cytometry was employed to analyze programmed cell death-ligand 1 (PD-L1) and Cluster of Differentiation 69 expression, while Western blotting assessed the levels of PD-L1, Janus Kinase 2 (JAK2), Signal Transducer and Activator of Transcription 3 (STAT3), p-JAK2, p-STAT3, and exosomal marker proteins. Additionally, enzyme-linked immunosorbent assay (ELISA) was conducted to measure concentrations of PD-L1, interferon-γ (IFN-γ), and tumor necrosis factor-β (TNF-β). Dp effectively inhibited TNBC cell proliferation and migration, as evidenced by CCK-8, colony formation, and scratch assays. Flow cytometry and Western blot analysis indicated a reduction in PD-L1 expression in TNBC cells. Meanwhile, we successfully isolated TNBC cell-derived exosomes, with ELISA experiments showing a decrease in PD-L1 expression in these exosomes following Dp treatment. In a co-culture system with TNBC and Jurkat cells, Dp enhanced Cluster of Differentiation 69 expression and reactivated Jurkat cells, resulting in increased secretion of IFN-γ and TNF-β. Additionally, Dp significantly reduced the p-JAK2/JAK2 and p-STAT3/STAT3 ratios in TNBC cells. Dp may exert its anti-TNBC effects by downregulating PD-L1 expression in TNBC cells and exosomes through the JAK2/STAT3 signaling pathway, potentially restoring T cell activity and modifying the tumor microenvironment.

CircDUSP16 mediates the effect of triple-negative breast cancer in pirarubicin via the miR-1224-3p/TFDP2 axis.

Triple-negative breast cancer (TNBC) is an aggressive molecular subtype of breast cancer characterized by a high recurrence rate, poor prognosis, and elevated mortality. Identifying novel molecular targets is crucial for developing more effective therapeutic strategies against TNBC. Recent studies have highlighted the role of circular RNAs (circRNAs) in the progression of TNBC. In this study, we identified and validated that circDUSP16 (hsa_circ_0003855) is significantly upregulated in TNBC cells, tissues, and plasma exosomes. Functional assays in vitro demonstrated that overexpression of circDUSP16 promoted the proliferation, migration and invasion of TNBC cells, weathers circDUSP16 knockdown exerted the opposite effect. In vivo studies confirmed that circDUSP16 knockdown can inhibit tumor growth. Using bioinformatics analysis, circDUSP16/miR-1224-3p/TFDP2 pathway was predicted and cascaded. Mechanistically, circDUSP16 was shown to promote the progression of TNBC via the miR-1224-3p/TFDP2 axis. Additionally, THP, a commonly used anthracycline chemotherapy drug, was found to downregulate circDUSP16, suggesting that its therapeutic effects on TNBC may be mediated through circDUSP16/miR-1224-3p/TFDP2 pathway. Our findings suggest that circDUSP16 is a promising biomarker and potential therapeutic target for TNBC.

Pentagalloyl Glucose from Bouea macrophylla Suppresses the Epithelial-Mesenchymal Transition and Synergizes the Doxorubicin-Induced Anticancer and Anti-Migration Effects in Triple-Negative Breast Cancer.

Background: Triple-negative breast cancer (TNBC) represents an aggressive form of breast cancer with few available therapeutic options. Chemotherapy, particularly with drugs like doxorubicin (DOX), remains the cornerstone of treatment for this challenging subtype. However, the clinical utility of DOX is hampered by adverse effects that escalate with higher doses and drug resistance, underscoring the need for alternative therapies. This study explored the efficacy of pentagalloyl glucose (PGG), a natural polyphenol derived from Bouea macrophylla, in enhancing DOX's anticancer effects and suppressing the epithelial-mesenchymal transition (EMT) in TNBC cells. Methods: This study employed diverse methodologies to assess the effects of PGG and DOX on TNBC cells. MDA-MB231 triple-negative breast cancer cells were used to evaluate cell viability, migration, invasion, apoptosis, mitochondrial membrane potential, and protein expression through techniques including MTT assays, wound healing assays, flow cytometry, Western blotting, and immunofluorescence. Results: Our findings demonstrate that PGG combined with DOX significantly inhibits TNBC cell proliferation, migration, and invasion. PGG enhances DOX-induced apoptosis by disrupting the mitochondrial membrane potential and activating caspase pathways; consequently, the activation of caspase-3 and the cleavage of PARP are increased. Additionally, the study shows that the combination treatment upregulates ERK signaling, further promoting apoptosis. Moreover, PGG reverses DOX-induced EMT by downregulating mesenchymal markers (vimentin and β-catenin) and upregulating epithelial markers (E-cadherin). Furthermore, it effectively inhibits STAT3 phosphorylation, associated with cell survival and migration. Conclusions: These results highlight the potential of PGG as an adjuvant therapy in TNBC treatment. PGG synergizes with DOX, which potentiates its anticancer effects while mitigating adverse reactions.

Polyanhydride Copolymer-Based Niclosamide Nanoparticles for Inhibiting Triple-Negative Breast Cancer: Metabolic Responses and Synergism with Paclitaxel.

The heterogeneity of tumors and the lack of effective therapies have resulted in triple-negative breast cancer (TNBC) exhibiting the least favorable outcomes among breast cancer subtypes. TNBC is characterized by its aggressive nature, often leading to high rates of relapse, metastasis, and mortality. Niclosamide (Nic), an Food and Drug Administration-approved anthelmintic drug, has been repurposed for cancer treatment; however, its application for TNBC is hindered by significant challenges, including strong hydrophobicity, poor aqueous solubility, and low bioavailability. This study aimed to develop Nic nanoparticles (Nic NPs) using biodegradable and biocompatible polyanhydride copolymers to enhance Nic's bioavailability and therapeutic efficacy. Nic NPs effectively inhibited migration, proliferation, and clonogenicity in both murine and human TNBC cells, inducing apoptosis and suppressing STAT3 signaling. For the first time, we utilized Raman spectroscopy and Seahorse extracellular flux assays to demonstrate the metabolic responses of TNBC cells to Nic NPs, revealing significant metabolic alterations, including the inhibition of mitochondrial respiration and glycolysis. Additionally, this study is the first to explore the combination therapy of repurposed Nic with the approved chemotherapeutic agent paclitaxel in the 4T1 TNBC immunocompetent mouse model. The combination of Nic NPs and paclitaxel significantly reduced tumor growth without adversely affecting the body weight of tumor-bearing mice. In summary, these findings suggest that Nic NPs could serve as a promising component in combination therapies for the effective treatment of TNBC.

Pirfenidone promotes cell cycle arrest and apoptosis of triple‑negative breast cancer cells by suppressing Hedgehog/GLI1 signaling.

Breast cancer is a common malignant tumor in women and triple-negative breast cancer (TNBC) is the most challenging type of breast cancer with poor prognosis. We aimed to elucidate the effects of pirfenidone, a FDA-approved oral anti-fibrotic drug which has recently shown antitumor potential, in the progression of TNBC and the underlying mechanisms. After TNBC cells were treated with pirfenidone, cell viability was evaluated using CCK-8 assay. The EDU staining was applied for reflecting the ability of cell proliferation. Additionally, cell cycle distribution and apoptotic rate of TNBC cells exposed to pirfenidone were determined by flow cytometry. The levels of proteins associated with cell cycle, apoptosis and Hedgehog/gliomaassociated oncogene homolog (GLI)1 signaling was examined through western blot. Then, GLI1 was upregulated to analyze the proliferation, cell cycle and apoptosis of TNBC cells in the presence of pirfenidone to reveal the regulatory mechanism. Pirfenidone dose-dependently decreased the viability and proliferation of MDA-MB-231 and HCC-1937 cells. Besides, the distribution of TNBC cells in G0/G1 phase was significantly elevated by pirfenidone, accompanied by downregulated levels of CyclinD1, CDK4 and CDK6. Simultaneously, pirfenidone caused remarkably increased apoptotic MDA-MB-231 and HCC-1937 cells, coupled with downregulated BCL2 expression as well as upregulated Bax, cleaved caspase3 and cleaved PARP expression. Expression of proteins related to Hedgehog/gliomaassociated oncogene homolog (GLI)1 signaling was tested through western blot. Particularly, GLI1 and PTCH1 levels were dose-dependently inhibited after pirfenidone exposure. Interestingly, GLI1 overexpression attenuated the influences of pirfenidone on the proliferation, cell cycle and apoptosis of TNBC cells. Collectively, pirfenidone arrests the cell cycle and promotes apoptosis of TNBC cells by suppressing Hedgehog/GLI1 signaling.

Fibroblast Growth Factor Receptor 4 Promotes Triple-Negative Breast Cancer Progression via Regulating Fatty Acid Metabolism Through the AKT/RYR2 Signaling.

Triple-negative breast cancer (TNBC) is the most aggressive subtype of breast cancer. Previous studies have found that fibroblast growth factor receptor 4 (FGFR4) plays a crucial role in tumor development and metastasis. However, the potential role and underlying mechanisms of FGFR4 in the progression of TNBC remain unclear. Statistical analysis of FGFR4 expression data in public databases was used to reveal its role in TNBC. qRT-PCR was used to detect FGFR4 expression levels. The impact of FGFR4 level changes on TNBC cell proliferation was assessed using CCK-8 and colony formation assays, while Transwell invasion assays and JC-1 staining were employed to analyze the effects of FGFR4 level changes on the invasiveness and survival capability of TNBC cells. Differentially expressed genes were subjected to Gene Ontology, KEGG, and GSEA enrichment analyses to identify associated signaling pathways. Additionally, Oil Red O staining, fatty acid metabolite detection, and Western blot analysis were used to investigate the impact of FGFR4 and its inhibitor fisogatinib, as well as the AKT activator SC79, on the metabolic reprogramming of fatty acids in TNBC cells. FGFR4 was found to be upregulated in breast cancer and correlated with poorer patient outcomes. Inhibition of FGFR4 resulted in reduced cell growth and invasion in TNBC cells. It also led to increased lipid accumulation, upregulated lipid biosynthesis-related genes, and downregulated lipolysis-related genes. Mechanistically, FGFR4 inhibition suppressed the activation of the AKT/RYR2 signaling pathway. Reactivating the AKT pathway reversed the suppressive effects of FGFR4 inhibition on TNBC progression. Dysregulated FGFR4 activates the AKT/RYR2 axis, leading to tumor proliferation, invasion, and altered lipid metabolism in TNBC. FGFR4 inhibition could potentially serve as a novel therapeutic strategy for TNBC treatment.

Role of Harmaline in Inhibiting c-Myc, Altering Molecular Typing, and Promoting Apoptosis in Triple-Negative Breast Cancer.

Triple-negative breast cancer (TNBC) lacks effective targeted, endocrine therapeutic agents and the development of novel agents is costly and time-consuming. The objective of this study was to identify pharmaceuticals and natural products utilized in clinical practice that have the potential to inhibit the expression of Cellular-myelocytomatosis oncogene (c-Myc), based on a review of the current literature. The aim was to assess the effect of the specified drugs on c-Myc expression in TNBC cells, determine the most potent inhibitor, and evaluate its impact on TNBC cell proliferation, invasive migration, and apoptosis, as well as the expression of estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER-2) at both the gene and protein levels. Explore its potential for treatment or adjuvant therapy for triple-negative breast cancer. Quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot were used to quantify gene and protein expression levels. Flow cytometry was employed to measure cell proliferation and apoptosis, while the Transwell assay was utilized to assess cell invasion and migration. Harmaline emerged as the strongest inhibitor, significantly decreasing the expression of c-Myc at both the gene and protein levels in TNBC cells. It also inhibited cell proliferation, invasion, and migration while promoting apoptosis in TNBC cells. Additionally, there was a varying increase in the expression of ER and PR genes and proteins. While the expression of the HER-2 gene was elevated, there was no significant change in HER-2 protein levels. Notably, the expression of the phosphorylated HER-2 protein increased. Harmaline was found to promote apoptosis and inhibit cell proliferation, invasion, and migration in TNBC cells by targeting the inhibition of c-Myc. It also induced the re-expression of the ER, PR, and HER-2 genes, as well as the ER and PR proteins.

FAM83H regulated by glis3 promotes triple-negative breast cancer tumorigenesis and activates the NF-κB signaling pathway.

Triple-negative breast cancer (TNBC) is a highly aggressive and invasive form of breast cancer (BC) with a high mortality rate and a lack of effective targeted drugs. Family with sequence similarity 83 member H (FAM83H) is critically implicated in tumorigenesis. However, the potential role of FAM83H in TNBC remains elusive. Here, we discovered that FAM83H exhibited high expression in tumor tissues of patients with TNBC and was associated with TNM stage. Gain- or loss-of-function experiments were conducted to explore the biological role of FAM83H in TNBC. Subsequently, functional enrichment analysis confirmed that FAM83H overexpression promoted TNBC cell proliferation, invasion, migration and epithelial-mesenchymal transition (EMT), accompanied by upregulation of cyclin E, cyclin D, Vimentin, N-cadherin and Slug. As observed, FAM83H knockdown showed anti-cancer effects, such as fostering apoptosis and inhibiting tumorigenicity and metastasis of TNBC cells. Mechanistically, FAM83H activated the NF-κB signaling pathway. Moreover, a dual-luciferase reporter assay demonstrated that GLIS family zinc finger 3 (GLIS3) bound to the promoter of FAM83H and enhanced its transcription. Notably, overexpression of GLIS3 significantly stimulated TNBC cell proliferation and invasion, and all of this was reversed by rescue experiments involving the knockdown of FAM83H. Overall, FAM83H exacerbates tumor progression, and in-depth understanding of FAM83H as a therapeutic target for TNBC will provide clinical translational potential for intervention therapy.

Mitochondria-localized MBD2c facilitates mtDNA transcription and drug resistance.

Mitochondria contain a 16-kb double stranded DNA genome encoding 13 proteins essential for respiration, but the mechanisms regulating transcription and their potential role in cancer remain elusive. Although methyl-CpG-binding domain (MBD) proteins are essential for nuclear transcription, their role in mitochondrial DNA (mtDNA) transcription is unknown. Here we report that the MBD2c splicing variant translocates into mitochondria to mediate mtDNA transcription and increase mitochondrial respiration in triple-negative breast cancer (TNBC) cells. In particular, MBD2c binds the noncoding region in mtDNA and interacts with SIRT3, which in turn deacetylates and activates TFAM, a primary mitochondrial transcription factor, leading to enhanced mtDNA transcription. Furthermore, MBD2c recovered the decreased mitochondrial gene expression caused by the DNA synthesis inhibitor cisplatin, preserving mitochondrial respiration and consequently enhancing drug resistance and proliferation in TNBC cells. These data collectively demonstrate that MBD2c positively regulates mtDNA transcription, thus connecting epigenetic regulation by deacetylation with cancer cell metabolism, suggesting druggable targets to overcome resistance.

Naphthoquinone-derived ZSW-4B induces apoptosis in triple-negative breast cancer via AMPK signalling activation

Triple-negative breast cancer (TNBC) is the most malignant molecular subtype of breast cancer and is characterized by aggressiveness, high mortality, significant heterogeneity, and poor prognosis. AMPK plays a critical role in maintaining the cellular energy balance, and its inactivation is associated with malignant breast cancer. Here, we identified the pharmacological mechanism of the 1,4-naphthoquinone derivative ZSW-4B. MTT, colony formation, and nude mouse xenograft tumour models demonstrated that ZSW-4B selectively inhibits the proliferation of TNBC cells both in vitro and in vivo. Flow cytometry and Western blot analysis revealed that ZSW-4B induces apoptosis in TNBC cells. Phosphoproteomic analysis revealed activation of the AMPK signalling pathway by ZSW-4B. Additionally, the application of the CRISPR-Cas9 system to genetically knockout AMPK in TNBC cell lines was demonstrated to reverse the antitumour effects elicited by ZSW-4B both in vitro and in vivo. In summary, ZSW-4B inhibits TNBC by inducing cellular apoptosis through the activation of AMPK.

Insulin-like growth factor-binding protein-3 is induced by tamoxifen and fulvestrant and modulates fulvestrant response in breast cancer cells.

Insulin-like growth factor binding protein-3 (IGFBP-3) exerts varying effects on estrogen receptor alpha (ERα)-positive and triple-negative breast cancer (TNBC) cells. In ERα-positive cells, IGFBP-3 is antiproliferative and proapoptotic. In contrast, IGFBP-3 stimulates proliferation in triple-negative breast cancer (TNBC) cells via EGFR activation. To identify potential mechanisms that underlie the opposing effects of IGFBP-3 on these two breast cancer subtypes, IGFBP-3 expression was determined in cell line models of both ERα-positive breast cancer and TNBC, and cells were treated with antiestrogens tamoxifen and fulvestrant. MCF-7 and T-47D cells expressed low levels of IGFBP-3 when compared to MDA-MB-231 and MDA-MB-468 cells. MCF-7 cells with acquired resistance to the selective estrogen receptor degrader fulvestrant expressed high IGFBP-3 and MCF-7 cells with constitutive IGFBP-3 expression were fulvestrant resistant. IGFBP-3 expression was increased in all cell lines upon treatment with fulvestrant or the selective estrogen receptor modulator tamoxifen and both fulvestrant and tamoxifen increased TNBC cell proliferation. Further, IGFBP-3 expression was increased by treatment with the GPER1 agonist G-1 and attenuated upon treatment with P17, a YAP/TAZ inhibitor. These data suggest that IGFBP-3 modulates breast cancer cells and is a mediator of breast cancer cell response to fulvestrant and tamoxifen.

Caffeic Acid Phenethyl Ester Suppresses Cytokine- and Chemotherapy-Induced Inflammation in Triple-Negative Breast Cancer via NF-κB Signalling

Background: Triple-negative breast cancer (TNBC) remains a significant clinical challenge due to its aggressive nature and lack of targeted therapies. In TNBC, inflammation contributes to tumour progression by promoting cell proliferation, survival, and migration. It may be triggered by cytokines such as TNF-α or chemotherapeutic agents such as doxorubicin (DOX). Thus, identifying agents that suppress inflammation in TNBC is of prime interest. Caffeic acid phenethyl ester (CAPE) is a naturally occurring anti-inflammatory compound that exhibits selective cytotoxicity against some cancer cells. However, its impact on cytokine or chemotherapy induced inflammation in TNBC has not yet been explored. Aim: This study aimed to investigate the effects of CAPE on TNF-α- or DOX-induced inflammation and metastatic markers in TNBC. Methods: The effects of CAPE and DOX on TNBC cell viability and migration were assessed using the MTT and wound healing assays, respectively. The effect of CAPE on the expression of pro-inflammatory cytokines, epithelial-mesenchymal transition (EMT) markers, and tumour invasion markers was evaluated using RT-qPCR. Results: CAPE inhibited TNF-α-induced proliferation and migration of TNBC cells. CAPE also suppressed TNF-α- and DOX-induced upregulation of NF-κB-regulated pro-inflammatory genes, IL-1B, IL-6, IL-8, and TNF-α, corroborating the evidence that CAPE suppresses NF-κB signalling. Additionally, CAPE suppressed EMT in TNF-α–stimulated and DOX-treated cells by downregulating vimentin and VCAM1. Furthermore, CAPE reduced the expression of the cancer invasion markers MMP2 and MMP9. Conclusions: We demonstrated the anticancer potential of CAPE and its ability to suppress cytokine and chemotherapy-induced inflammation. This study offers novel insights into the role of CAPE in suppressing inflammation and metastasis markers in TNBC, specifically in the context of TNF-α and DOX-induced NF-κB signalling. These findings underscore the urgent need to further study CAPE as a possible adjuvant for treating patients with TNBC, especially those undergoing chemotherapy.

Chaperonin‐containing TCP1 subunit 6A inhibition via TRIM21‐mediated K48‐linked ubiquitination suppresses triple‐negative breast cancer progression through the AKT signalling pathway

AbstractBackgroundTriple‐negative breast cancer (TNBC) is distinguished by a significant likelihood of distant recurrence and an unfavourable prognosis. However, the underlying molecules and mechanisms have not been fully elucidated.MethodsWe investigated the expression profile and clinical relevance of chaperonin‐containing TCP1 subunit 6A (CCT6A) in TNBC. We performed cell function assays on TNBC cells with CCT6A knockdown or overexpression. To further explore the mechanism of action of CCT6A, RNA sequencing and co‐immunoprecipitation–mass spectrometry analyses were utilized. Rescue and ubiquitination assays evaluated the impact of TRIM21‐mediated CCT6A ubiquitination and degradation on TNBC progression in vitro and in vivo. Finally, we studied the potential of Ipatasertib, a pharmacological AKT inhibitor, and/or anti‐PD1 therapy in inhibiting TNBC progression.ResultsElevated CCT6A expression in TNBC patients was associated with an adverse prognosis and lymph node metastasis. Mechanistically, CCT6A facilitated cell migration, invasion, epithelial‐mesenchymal transition and proliferation by activating the phosphatidylinositol 3‐kinase (PI3K)/AKT pathway. The TRIM21 RING domain is an E3 ligase, facilitating the K48‐linked ubiquitination‐mediated degradation of CCT6A, thereby impeding TNBC progression. Moreover, in the tumour tissues of the CCT6A‐overexpressing mice, the quantity of CD8+ T cells and the concentration of secreted interferon‐gamma were decreased, whereas in the group double‐overexpression of CCT6A and TRIM21, they were elevated; the opposite was observed in the knockdown and double‐knockdown groups. Ipatasertib demonstrated enhanced efficacy in inhibiting cell proliferation, invasion and migration in TNBC cells ectopically expressing CCT6A. When Ipatasertib and anti‐PD1 therapies were combined, both the tumour volume and mass exhibited a notable reduction, while the expression of CD45+CD8+ T cells increased, and that of CD45+CD4+CTLA4+ and CD45+CD4+PD1+ T cells decreased.ConclusionsOur findings indicate that TRIM21 inhibits TNBC progression by facilitating the K48‐linked ubiquitination‐mediated degradation of CCT6A via the PI3K/AKT signalling pathway. This highlights the potential of Ipatasertib and/or anti‐PD1 as therapeutic strategies, particularly for TNBC patients overexpressing CCT6A.Key points Chaperonin TCP1 subunit 6A (CCT6A) plays an oncogenic role in triple‐negative breast cancer (TNBC) through the AKT signaling pathway. TRIM21 facilitated K48‐linked ubiquitination‐mediated degradation of CCT6A, thereby impeding TNBC progression. Our study collectively underscores the potential of Ipatasertib in conjunction with anti‐PD1 therapy as a promising strategy to counteract CCT6A/AKT hyperactivity‐driven TNBC progression.

Autocrine Motility Factor and Its Peptide Derivative Inhibit Triple-Negative Breast Cancer by Regulating Wound Repair, Survival, and Drug Efflux.

Triple-negative breast cancer (TNBC) presents a significant challenge in oncology due to its aggressive nature and limited targeted therapeutic options. This study explores the potential of autocrine motility factor (AMF) and an AMF-derived peptide as novel treatments for TNBC. AMF, primarily secreted by neoplastic cells, plays a crucial role in cancer cell motility, metastasis, and proliferation. The research demonstrates that AMF and its derived peptide inhibit TNBC cell proliferation by modulating cellular migration, redox homeostasis, apoptotic pathways, and drug efflux mechanisms. Dose-dependent antiproliferative effects were observed across three TNBC cell lines, with higher concentrations impairing cellular migration. Mechanistic studies revealed decreased glucose-6-phosphate dehydrogenase expression and elevated reactive oxygen species production, suggesting redox imbalance as a primary mediator of apoptosis. Combination studies with conventional therapeutics showed near-complete eradication of resistant TNBC cells. The observed reduction in p53 levels and increased intranuclear doxorubicin accumulation highlight the AMF/AMF peptide's potential as multidrug resistance modulators. This study underscores the promise of using AMF/AMF peptide as a novel therapeutic approach for TNBC, addressing current treatment limitations and warranting further investigation.

Significance of LIF/LIFR Signaling in the Progression of Obesity-Driven Triple-Negative Breast Cancer.

American women with obesity have an increased incidence of triple-negative breast cancer (TNBC). The impact of obesity conditions on the tumor microenvironment is suspected to accelerate TNBC progression; however, the specific mechanism(s) remains elusive. This study explores the hypothesis that obesity upregulates leukemia inhibitory factor receptor (LIFR) oncogenic signaling in TNBC and assesses the efficacy of LIFR inhibition with EC359 in blocking TNBC progression. TNBC cell lines were co-cultured with human primary adipocytes, or adipocyte-conditioned medium, and treated with EC359. The effects of adiposity were measured using cell viability, colony formation, and invasion assays. Mechanistic studies utilized RNA-Seq, Western blotting, RT-qPCR, and reporter gene assays. The therapeutic potential of EC359 was tested using xenograft and patient-derived organoid (PDO) models. The results showed that adipose conditions increased TNBC cell proliferation and invasion, and these effects correlated with enhanced LIFR signaling. Accordingly, EC359 treatment reduced cell viability, colony formation, and invasion under adipose conditions and blocked adipose-mediated organoid growth and TNBC xenograft tumor growth. RNA-Seq analysis identified critical pathways modulated by LIF/LIFR signaling in diet-induced obesity mouse models. These findings suggest that adiposity contributes to TNBC progression via the activation of the LIF/LIFR pathway, and LIFR inhibition with EC359 represents a promising therapeutic approach for obesity-associated TNBC.

DLAT promotes triple-negative breast cancer progression via YAP1 activation

ABSTRACT Background Breast cancer (BC) is the most prevalent malignant tumor in women globally. Triple-negative breast cancer (TNBC) represents the most malignant and invasive subtype of BC. New therapeutic targets are urgently needed for TNBC owing to its receptor expression characteristics, which render it insensitive to traditional targeted and endocrine therapies for BC. The role and mechanisms of dihydrolipoamide S-acetyltransferase (DLAT) as a crucial molecule in glycometabolism and cuproptosis-related biological processes in tumors remain to be explored. Methods DLAT expression was investigated using bioinformatics methods and quantitative real-time polymerase chain reaction. Subsequently, the MTT assay, colony formation assay, and migration-invasion assay were performed to validate the effect of DLAT on TNBC cell viability, proliferation, and migration. Cytoplasmic-nuclear separation experiments, western blot analysis, and co-immunoprecipitation assays were performed to elucidate the underlying molecular mechanisms. Results This study revealed a robust correlation between elevated DLAT expression in BC and unfavorable prognosis in patients, with higher expression of DLAT compared to other subtypes in TNBC. Functional cytology experiments indicated that DLAT plays a tumor-promoting role in TNBC. Mechanistic studies showed that DLAT directly interacts with YAP1, leading to the dephosphorylation and activation of YAP1 and its increased nuclear translocation, thereby transcriptionally activating and regulating downstream oncogenes, promoting the malignant phenotype of TNBC. Rescue experiments indicated that DLAT promotes the malignant behavior of TNBC through a YAP1-dependent pathway. Conclusions Our research unveiled the significant involvement of DLAT in TNBC, along with the potential for modulating DLAT/YAP1 activity as a targeted treatment strategy for TNBC.

Blestriarene C exerts an inhibitory effect on triple-negative breast cancer through multiple signaling pathways.

Breast cancer is the most common cancer worldwide, the leading cause of cancer death in women, and the fifth leading cause of cancer death. Triple negative breast cancer (TNBC), with high metastasis and mortality rates, is the most challenging subtype in breast cancer treatment. There is an urgent need to develop anti-TNBC drugs with significant efficacy, low side effects and good availability. In early drug screening, blestriarene C was found to have inhibitory effects on TNBC cells. In this article, we further explore the mechanisms associated with blestriarene C for breast cancer. In this article, we take the approach of network pharmacology combined with in vivo and in vitro experiments. Network pharmacology analysis was used to predict the active components in Baiji, and to investigate the hub targets and related mechanisms of BC in TNBC treatment. The mechanism of anti-TNBC in vitro was evaluated by CCK-8 assay, cell apoptosis and cell cycle assays, wound healing assay, WB assay, and molecular docking analysis. The inhibition effect in vivo was test in subcutaneous tumor models established in mice. Through network pharmacology analysis and experiments, we screened out BC as the main active ingredient, and found that BC could inhibit the Ras/ERK/c-Fos signaling pathway while downregulating the expression of HSP90AA1 and upregulating the expression of PTGS2, thereby promoting apoptosis, causing S-phase cycle arrest, and inhibiting the proliferation and migration of BT549 cells. The in vivo results illustrated that BC inhibited the growth of TNBC tumors and has a high safety profile. By integrating network pharmacology with in vitro and in vivo experiments, this study demonstrated that BC inhibited the proliferation and migration of TNBC cells by inhibiting the Ras/ERK/c-Fos signaling pathway, promoting apoptosis, and causing S-phase cycle arrest. This study provides new evidence for the use of BC as a novel drug for TNBC treatment.