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Proteomic signatures of adipocyte recruitment in breast cancer.

The tumor microenvironment (TME) is increasingly recognized as a dynamic regulator of breast cancer progression, with adipocytes functioning as active contributors rather than passive bystanders. Here, we investigated the proteomic and morphologic reprogramming of breast cancer-associated adipocytes (BrCAAs) in response to triple-negative breast cancer (TNBC). Using conditioned medium from HCC1143 cells, we established an in vitro BrCAA model and performed mass spectrometry-based proteomics. Comparative profiling revealed 256 differentially expressed proteins, enriched for pathways including fatty acid degradation, carbon metabolism, and glycogen turnover, consistent with a metabolic shift from energy storage to energy supply. Gene ontology and protein-protein interaction analyses further identified cytoskeletal remodeling, adhesion dynamics, and secretory pathway activation, supporting BrCAA-driven microenvironmental remodeling. In the MMTV-PyMT mouse model, morphometric analysis demonstrated progressive size reduction and increased contour irregularity of adipocytes adjacent to tumors, correlating with proteomic evidence of metabolic stress. Importantly, BrCAAs localized at tumor interfaces were associated with increased microvessel density and CD105+ endothelial activation compared to desmoplastic zones. Proteomic enrichment highlighted pro-angiogenic remodeling, with validation of basigin (BSG), integrin αV (ITGAV), and 2,4-dienoyl-CoA reductase 1 (DECR1). Collectively, our findings establish BrCAAs as metabolically and structurally reprogrammed stromal components that promote tumor metabolism and localized angiogenesis, representing potential therapeutic targets in aggressive breast cancer.

Female

UNCX/SIN3A-Mediated H4K8 decrotonylation suppresses FOXO3 to drive TNBC progression and docetaxel resistance.

Triple-negative breast cancer (TNBC) remains a clinically challenging subtype characterized by aggressive behavior and limited treatment options. Though docetaxel remains a cornerstone chemotherapy for TNBC, the frequent emergence of resistance highlights the urgent need to identify novel therapeutic targets. In this study, we report that uncoordinated homeobox (UNCX) is upregulated in docetaxel-resistant breast cancer cells, genomically amplified in breast cancer, and associated with poor survival in breast carcinoma patients. Functional studies revealed that UNCX promotes breast cancer cell proliferation, migration and reduces the docetaxel sensitivity. Mechanistically, UNCX functions as a transcriptional repressor by recruiting the SIN3A complex. Genome-wide profiling indicated that the UNCX/SIN3A complex directly binds to the promoters of tumor-suppressor genes including FOXO3, and represses their transcription by removing histone H4K8 crotonylation (H4K8cr). Additionally, the UNCX/SIN3A complex enhances FOXO3 phosphorylation and inhibits its nuclear translocation, further inhibiting its activity. Notably, SIN3A knockdown, FOXO3 overexpression, or crotonylation restoration effectively reverses UNCX-induced malignant phenotypes. These findings collectively establish the UNCX/SIN3A-H4K8cr-FOXO3 axis as a pivotal epigenetic regulator of TNBC progression and chemoresistance, revealing new avenues for targeted therapeutic development against this aggressive breast cancer subtype.

Humans

[BRCA1 Gene's Mutations And Hereditary Breast Cancer: Genetic, Biological, And Clinical Aspects].

INTRODUCTION: Hereditary breast cancer accounts for approximately 5 to 10% of all breast cancer cases. Mutations in the BRCA1 gene, which plays a central role in DNA repair and cell cycle regulation, are the main cause of these familial forms and are strongly associated with aggressive subtypes, particularly triple-negative breast cancer. METHODS: A narrative literature review was conducted using biomedical databases (PubMed, Scopus, Web of Science, Google Scholar) between January 2024 and June 2025. Eligible publications addressed the genetic, biological, epidemiological, and clinical aspects of BRCA1 in hereditary breast cancer. RESULTS: BRCA1 ensures genomic stability through its roles in DNA repair, cell cycle checkpoints, and transcriptional regulation. Most mutations are truncating or missense variants, with some reported as founder mutations (e.g., c.68_69delAG, c.5266dupC, 943ins10). Women carrying germline BRCA1 mutations have an estimated lifetime risk of 56-87% of developing breast cancer, with a strong association with aggressive molecular subtypes, especially triple-negative breast cancer. CONCLUSION: A comprehensive understanding of BRCA1 mutations is crucial to enhance prevention, screening, and personalized management of hereditary breast cancer. In low-resource settings, the integration of genetic testing and counseling remains a major challenge and a public health priority to reduce disparities in cancer care.

Humans

Efficacy and Genomic Analysis of HER2-Mutant Metastatic Triple-Negative Breast Cancer Treated with Neratinib Alone or with Trastuzumab in the SUMMIT Basket Trial.

PURPOSE: Human epidermal growth factor receptor 2 (HER2) mutations occur in 1% to 3% of triple-negative breast cancers (TNBC), representing a novel target for biomarker-directed treatment. In the SUMMIT basket trial (NCT01953926), patients with HER2-mutant, metastatic TNBC received neratinib (240 mg/day) or neratinib + trastuzumab (N + T; neratinib 240 mg/day, intravenous trastuzumab 8 mg/kg initially and then 6 mg/kg every 3 weeks). We report final results from the neratinib and N + T TNBC cohorts. PATIENTS AND METHODS: Primary endpoint: investigator-assessed objective response rate at first postbaseline tumor assessment (ORRfirst); secondary endpoints included confirmed ORR by investigator, clinical benefit rate (CBR), and progression-free survival (PFS); exploratory endpoint included circulating tumor DNA (ctDNA) collected at baseline, during treatment, and at the end of treatment. RESULTS: Twenty-seven patients were enrolled between July 2014 and September 2021. Confirmed ORRs were 40% [95% confidence interval (CI), 12.2-73.8] for neratinib (n = 10) and 35.3% (95% CI, 14.2-61.7) for N + T (n = 17). CBRs were 40% (95% CI, 12.2-73.8) and 47.1% (95% CI, 23-72.2), respectively; median PFS times were 2.89 (95% CI, 0.95-5.52) and 6.24 months (95% CI, 2.10-8.18), respectively. HER2 mutation variant allele frequencies in ctDNA from patients with response or stable disease decreased upon treatment and increased upon progression. Serial ctDNA sequencing revealed emergence or increase in on-pathway (ERBB3) and off-pathway (KRAS and TP53) mutations. The most common treatment-emergent adverse events were diarrhea, nausea, and constipation. CONCLUSIONS: N + T in patients with HER2-mutant metastatic TNBC seemed to prolong responses versus neratinib alone, representing a novel approach for patients with biomarker-defined metastatic TNBC. Based on these and previously published data, neratinib-based combinations are endorsed by the National Comprehensive Cancer Network guidelines for patients with hormone receptor-positive or -negative metastatic breast cancer with activating HER2 mutations. See related commentary by Lloyd et al., p. 3715.

Adult

Chronic nitric oxide mediates dual-layer gene regulation through mRNA m6A positional remodeling and parallel transcriptional reprogramming.

Nitric oxide (NO) is a pleiotropic free radical that functions as a master regulator of gene expression, and its sustained production within the tumor microenvironment reshapes the epitranscriptomic state of cancer cells. We previously demonstrated that NO inhibits the m6A mRNA demethylases FTO and ALKBH5 through dinitrosyliron complex formation while leaving the methyltransferase METTL3 intact, a demethylase-specific perturbation that increases global m6A on mRNA. Here, integrating m6A-RIP-seq and RNA-seq from triple-negative breast cancer cells, we show that chronic NO does not produce the uniform hypermethylation anticipated from demethylase inhibition. Instead, it redistributes m6A on mRNA, enriching the 5'UTR and coding sequence while depleting the 3'UTR and departing from the canonical stop-codon and 3'UTR topology. We found that the position of m6A, rather than its intensity or mere presence, shapes the outcome, in part by determining which reader protein is predicted to recognize it. In parallel, NO drives a canonical NF-κB and inflammatory transcriptional program. The transcriptional program is independent of the m6A methylome in both which genes respond and how strongly they respond, ruling out a linear methylome-to-transcriptome cascade; even so, m6A position remains associated with the direction of change among responding transcripts. The 3'UTR is the primary site of m6A loss and shows a suggestive computational link to miRNA-mediated regulation. Sense-antisense coordination reinforces the transcriptional response without bridging the two programs. These findings demonstrate that NO not only increases m6A abundance, but it also rewrites the m6A positional code, establishing spatial reprogramming of the epitranscriptome as a previously unrecognized mode of gene regulation.

RNA Methylation

Prognostic and predictive value of HRD in early triple negative breast cancer (TNBC).

This review explores the emerging role of homologous recombination deficiency (HRD) as both a prognostic and predictive biomarker in early-stage triple-negative breast cancer (TNBC). HRD arises from the defective repair of DNA double-strand breaks through homologous recombination, resulting in genomic instability and increased sensitivity to DNA-damaging agents such as platinum compounds. The review outlines the biological basis of HRD, including genomic signatures such as loss of heterozygosity, telomeric allelic imbalance, and large-scale state transitions, and highlights its prevalence in TNBC compared with other breast cancer subtypes. Clinical trials have shown that HRD-positive patients often achieve higher pathological complete response rates and improved disease-free survival when treated with chemotherapy. However, conflicting evidence across trials underscores the need for more reliable and standardized methods for HRD assessment. The review also explores the therapeutic potential of poly(ADP-ribose) polymerase inhibitors in TNBC, particularly in BRCA-mutated or HRD-positive tumors. Agents such as olaparib, talazoparib, and niraparib have demonstrated promising efficacy in both neoadjuvant and adjuvant settings with some trials suggesting that selected patients may avoid chemotherapy. Furthermore, HRD-positive tumors are characterized by increased genomic instability and a higher neoantigen burden, promoting immune cell infiltration, particularly of tumor-infiltrating lymphocytes, which may enhance responsiveness to immune checkpoint inhibitors. Overall, current evidence supports the role of HRD as a promising biomarker in TNBC. However, further research is required to refine its clinical utility and to integrate HRD testing into personalized treatment strategies, especially in combination with emerging therapies such as immunotherapy.

Humans

Four-dimensional data independent acquisition proteomics and metabolomics reveal mechanisms of hydrogen-rich water at Zusanli (ST36) point against triple-negative breast cancer in mice.

OBJECTIVE: To develop a safe and effective green therapy for triple-negative breast cancer, this study combines hydrogen-rich water with acupuncture point injection, and finds that it can prevent tumor growth and minimize cancer metastasis. METHODS: After 21 d of hydrogen rich water injection treatment on 4T1 (mouse breast cancer cells) xenograft mice, in order to systematically identify differentially expressed proteins in tumor samples between the model group and the Zusanli (ST36) group injected with hydrogen rich water at acupoints, with a focus on functional proteins or signaling pathways related to tumor occurrence and development, researchers conducted four-dimensional data independent acquisition (4D-DIA) proteomic analysis on tumor tissues. In order to further investigate the dynamic changes of metabolites after therapeutic intervention, researchers conducted liquid chromatography-tandem mass spectrometry untargeted metabolomics identification and analysis on mouse serum. The results of the joint proteomics-metabolomics analysis were validated using experimental methods such as immunofluorescence, Western blotting, and quantitative reverse transcription polymerase chain reaction detection. RESULTS: Injecting hydrogen-rich water into acupoints significantly inhibited tumor growth (P < 0.05). 4D-DIA proteomics and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses uncovered pathways such as T helper 1 cell (Th1) and T helper 2 cell (Th2) cell differentiation. The KEGG metabolic pathways identified in the metabolomics analysis included galactose metabolism along with fructose and mannose metabolism. Based on the combined proteomics and metabolomics analysis, the key pathways included the C-type lectin receptor signaling pathway. The major cancer-related differential proteins detected in Th1 and Th2 cell differentiation [interleukin 6 signal transducer, nuclear factor of activated T cells 4, recombinant mitogen activated protein kinase 10 (MAPK10), and MAPK11] were upregulated after the injection of hydrogen-rich water into the Zusanli (ST36) acupoint, whereas Linker for activation of T cells (Lat), signal transducer and activator of transcription 1, and protein kinase C, theta were downregulated. CONCLUSION: The injection of hydrogen-rich water into the Zusanli (ST36) acupoint effectively inhibited the hyperplasia of 4T1 BC cells and enhanced their apoptosis, potentially exerting a therapeutic effect through multiple pathways and targeting various sites.

Animals

Histopathological evaluation of RPL5 expression in triple-negative breast cancer: an integrated immunohistochemical and transcriptomic study.

Triple-negative breast cancer (TNBC) is an aggressive subtype of breast cancer characterized by high invasiveness, limited therapeutic options, and unfavorable clinical outcomes. Ribosomal protein L5 (RPL5), a component of the large ribosomal subunit, has been implicated in ribosome biogenesis, translational regulation, and p53-associated cellular processes. This study investigated the immunohistochemical expression pattern of RPL5 in TNBC tissues and explored its potential biological significance through integrated transcriptomic analyses. Tumor tissues from 37 patients with TNBC and 7 adjacent non-tumorous breast tissues were collected from the Affiliated Tumor Hospital of Xinjiang Medical University between December 2017 and December 2023. RPL5 protein expression was evaluated by immunohistochemistry, and its association with clinicopathological characteristics was analyzed. Public transcriptomic datasets from TCGA-BRCA and GEO were further used to validate RPL5 expression patterns in TNBC. Co-expression analysis and Gene Ontology (GO)/Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were performed to investigate potential biological functions and signaling pathways associated with RPL5. Immunohistochemical analysis demonstrated significantly lower RPL5 protein expression in TNBC tissues compared with adjacent normal breast tissues (p=0.001). In contrast, transcriptomic analyses revealed significantly higher RPL5 expression in TNBC compared with non-TNBC breast cancer subtypes (p<0.001). No significant associations were observed between RPL5 expression and clinicopathological parameters, including age, tumor size, menopausal status, TNM stage, histological grade, or lymph node metastasis (all p>0.05). Survival analysis showed no significant difference in overall survival between patients with high and low RPL5 expression. Functional enrichment analyses indicated that RPL5-related genes were predominantly involved in ribosome biogenesis, translational regulation, and p53-related signaling pathways. These findings suggest that abnormal RPL5 expression may be associated with TNBC biology through ribosome-related programs, although causal roles require functional validation. RPL5 may represent a potential histopathological and molecular indicator associated with TNBC biology, although its precise functional role requires further experimental validation.

Humans

[Pathogenic large duplication in TP53 as a hereditary predisposing factor in breast cancer].

AIM: Germline pathogenic variants of TP53 are associated with Li-Fraumeni syndrome and represent a high risk for hereditary breast and ovarian cancer. We identified a germline, multi-exon heterozygous duplication variant in TP53, NM_000546.6:dup(ex2-5), in a young triple-negative breast cancer patient. We aimed to assign its pathogenicity. METHODS: DNA and RNA (cDNA) level specific amplification tests and sequencings were performed to identify the genomic duplication breakpoint and to detect the presence of defective transcripts. RESULTS: cDNA tests revealed aberrant transcript, which causes a shift in the reading frame. Allelic imbalance was also observed, indicating degradation of the defective RNA product. By locating the breakpoints at the DNA level, we determined that 6975 bp was repeated in tandem and in the same orientation. We also revealed the possible mechanism of the structural rearrangement. CONCLUSIONS: We established that the duplication identified at DNA level manifested in the mRNA and coded for a non-functional protein. Based on these data, we were able to classify this duplication variant as pathogenic, which affects the patient's therapeutic options and justifies genetic screening of family members.

Adult

Identification and analysis of metabolic reprogramming-related genes in triple-negative breast cancer.

Triple-negative breast cancer (TNBC) is notorious for its rapid progression, tendency to metastasize, high recurrence rates, dismal outcomes, and limited treatment options, underscoring the urgent need to uncover new biomarkers and molecular pathways to enhance diagnosis, prognosis, and therapeutic strategies. Metabolic reprogramming continues to play a role throughout the life cycle of cancer, evolving and adapting. In this study, we aimed to identify specific genes associated with metabolic reprogramming in TNBC, which can potentially become unique biomarkers of this cancer. TNBC datasets retrieved from the Gene Expression Omnibus were employed to pinpoint genes exhibiting altered expression linked to tumor metabolic reprogramming. Key genes were accurately screened through machine learning algorithms, and then externally verified using the TBNC dataset based on the Cancer Genome Atlas database. Finally, immunohistochemical methods were used to clinically confirm the differential expression and trends of these key genes. Our analysis accurately identified four genes-CLEC7A, IRS1, RSPO3, and ALB-that are closely correlated with the metabolic reprogramming characteristics of cancer, and could be regarded as innovative biomarkers for TNBC. This opens a new avenue for further investigation into the mechanisms of metabolic reprogramming in TNBC and new treatment strategies.

Humans

Exploring trop-2-directed ADCs monotherapy and combination therapy in pretreated mTNBC: a real-world study.

PURPOSE: Although Trop-2 antibody-drug conjugates (ADCs) have improved outcomes in pretreated metastatic triple-negative breast cancer (mTNBC), resistance remains common and the optimal combination strategy in routine practice is unclear. METHODS: In this retrospective real-world study, we identified patients with mTNBC from a health record-derived database who received sacituzumab govitecan or sacituzumab tirumotecan in the later-line setting between April 2020 and December 2025. Patients received at least two cycles of Trop-2 ADC therapy as monotherapy, plus a PD-1 inhibitor (dual-agent combination), or plus a PD-1 inhibitor and an antiangiogenic agent (triple-agent combination). RESULTS: Descriptively, the ORR was 57.1% in the triple-agent combination group, 38.5% in the dual-agent combination group, and 31.7% in the monotherapy group. Median follow-up was 15.2 months (95% CI, 8.7-20.6). Median progression-free survival (mPFS) was 15.4 months (95% CI, 5.3-NA) in the triple-agent combination group, 10.0 months (95% CI, 4.2-NA) in the dual-agent combination group, and 3.8 months (95% CI, 3.2-5.2) in the monotherapy group. Severe treatment-related toxicity was not increased in the combination groups. Exploratory analyses identified a genomic scoring system that may enable stratification of patients with a higher likelihood of benefiting from the triple-agent combination. CONCLUSION: To our knowledge, this study represents one of the earliest real-world evaluations of this triple-agent strategy in previously treated mTNBC, providing a basis for further prospective validation and biomarker-guided application.

Humans

Time- and Dose-Resolved DIA-PASEF Proteomics Maps the Transition from Adaptive Stress to Apoptotic Collapse in Melittin-Treated MDA-MB-231 Cells.

Melittin, the cytolytic peptide of honeybee venom, exhibits potent anticancer activity in triple-negative breast cancer (TNBC), yet the molecular programs underlying its cytotoxic effects remain incompletely defined. To address this gap, MDA-MB-231 TNBC cells were exposed to melittin at half-maximal inhibitory concentration(half IC50) and IC50 across early(0.5, 1, and 2 h), mid(3, 4 h), and late (12, 24 h) time windows. Proteomic profiling was performed using label-free data-independent acquisition(DIA) parallel accumulation-serial fragmentation(PASEF). Approximately 5800 proteins were quantified, revealing distinct dose-dependent stress responses. An integrative exploratory framework combining time-resolved log2 fold-change trajectories, area-under-the-curve(AUC) based temporal prioritization, and independent heatmap visualization identified proteins associated with melittin-induced stress remodeling. Half IC50 exposure showed a transient stress-adaptive signature characterized by chromatin remodeling(HMGN2, H2AZ1), structural and RNA-associated buffering(LRRC7), and indirect mitochondrial quality-control signaling(CPAMD8, SPATA4), which progressively weakened over time. In contrast, IC50 treatment induced rapid chromatin remodeling dominated by histone H1 variants(H1.4, H1.2), early RNA instability(LRRC7), and late-stage cytoskeletal disassembly marked by MICAL3 induction, consistent with progression toward apoptosis. These trajectories paralleled dose-dependent apoptotic phenotypes. Overall, data suggest that melittin elicits dose- and time-dependent proteomic stress responses in TNBC cells and identify candidate trajectory-associated proteins and pathways linked to adaptive stress remodeling or progression toward cytotoxic collapse.

Melitten

Exploration of body mass index and circulating metabolic factors as predictors of metformin benefit in the Canadian Cancer Trials Group MA.32.

BACKGROUND: In the MA.32 randomized adjuvant breast cancer trial, metformin (vs placebo) did not impact invasive disease-free survival or overall survival in estrogen and/or progesterone receptor-positive or -negative breast cancer; exploratory analyses suggested a benefit in HER2-positive breast cancer. We investigated whether body mass index (BMI) and obesity-associated blood variables predicted metformin benefit in immunohistochemically defined breast cancer subtypes (luminal [estrogen/progesterone receptor positive, HER2 negative], triple-negative breast cancer [estrogen receptor, progesterone receptor, HER2 negative], HER2 positive). METHODS: A total of 3649 nondiabetic patients with high risk T1-3, N0-3, M0 breast cancer were randomly assigned. Baseline fasting plasma was assayed for insulin, glucose, leptin, and C-reactive protein; Homeostasis Model Assessment was calculated. For each breast cancer subtype and each outcome (distant recurrence free survival, overall survival, invasive disease-free survival), Cox models examined interactions of BMI and blood variables with metformin vs placebo outcomes. RESULTS: Mean age was 51.1-53.0&#x2009;years; mean BMI was 27.3-27.5&#x2009;kg/m2. Most cancers were T2, N0, or N1 and grade 2-3; 2104 (57.7%) were luminal, 925 (25.3%) TN, and 620 (17.0%) HER2 positive. Median follow-up was 95.9&#x2009;months. In luminal breast cancer, statistically significant interactions were identified for leptin, insulin, and Homeostasis Model Assessment on distant recurrence-free survival, and in triple-negative breast cancer, a statistically significant interaction was identified for glucose on distant recurrence-free survival, with potential adverse effects of metformin at lower levels of each variable. In those with HER2-positive breast cancer, there was no variable that predicted metformin benefit. CONCLUSIONS: Body mass index and blood variables did not identify subgroups with luminal or triple-negative breast cancer who benefited from metformin or those with HER2-positive breast cancer who did not benefit. CLINICAL TRIAL REGISTRATION NUMBER: ClinicalTrials.gov NCT01101438: 2010-04-09.

Female

Multi-omics integration uncovers epigenetic control of metabolic reprogramming in triple-negative breast cancer.

Triple-negative breast cancer (TNBC) is an aggressive subtype characterized by the absence of estrogen, progesterone, and HER2 receptors, limiting effective targeted therapies. Increasing evidence suggests that metabolic reprogramming, a hallmark of TNBC progression, is driven by underlying epigenetic mechanisms such as DNA methylation. The represented study performed an integrative analysis of transcriptomic (RNA-seq) and methylome data to uncover the metabolic-epigenetic interplay in TNBC. Differential gene expression analysis using DESeq2 revealed significant dysregulation of key metabolic genes, including upregulation of genes encoding glycolytic and serine biosynthesis enzymes and downregulation of metabolic tumor suppressors. Genome-wide methylation profiling identified extensive cytosine-phosphate-guanine (CpG) hypermethylation events associated with transcriptional repression, particularly in promoter regions. Integrative analysis pinpointed a subset of metabolism-related genes exhibiting both differential expression and methylation, such as FBP1, RASSF1A, and PHGDH. Pathway enrichment analysis highlighted aberrations in glycolysis/gluconeogenesis, fatty acid metabolism, and one-carbon pathways (adjusted p&#x2009;<&#x2009;0.01). Importantly, TNBC patients with hypermethylated metabolic gene signatures displayed significantly shorter overall survival (log-rank p&#x2009;<&#x2009;0.05). These findings reveal that DNA methylation-driven metabolic dysregulation contributes to TNBC aggressiveness and may provide novel biomarkers and therapeutic targets at the metabolic-epigenetic interface.

Humans

LncRNA HAR1A in triple-negative breast cancer: mechanisms and the role of polymorphism rs 6089838 in susceptibility.

BACKGROUND: Long non-coding RNAs (lncRNAs) are increasingly recognized as crucial regulators and potential biomarkers in triple-negative breast cancer (TNBC). This study examined the link between the rs6089838 polymorphism in HAR1A and TNBC susceptibility/progression and function. RESEARCH DESIGN AND METHODS: 197 TNBC patients and 185&#xa0;healthy controls were recruited. Rs6089838 genotyping and serum lncRNA HAR1A quantification were performed using qRT PCR. Survival was analyzed via KM and Cox regression.. Cellular proliferation, migration, and invasion were measured using CCK-8 and Transwell assays. RESULTS: The GG genotype significantly lowered TNBC risk versus the AA genotype (OR =0.393, p&#x2009;=&#x2009;0.002). GA/GG genotypes were associated with more favorable clinicopathological features. Serum lncRNA HAR1A was downregulated in TNBC patients (p&#x2009;<&#x2009;0.001) and was positively correlated with the protective G allele frequency (p&#x2009;<&#x2009;0.001). GA/GG carriers showed significantly longer overall survival than AA homozygotes (p&#x2009;<&#x2009;0.001). Functional studies confirmed that HAR1A overexpression via pcDNA3.1 suppressed proliferation, migration, and invasion in breast cancer cell lines. Conversely, siRNA-mediated lncRNA HAR1A knockdown enhanced these oncogenic traits. CONCLUSION: The G allele of HAR1A rs6089838 represents a protective variant against TNBC susceptibility and progression, likely through HAR1A's tumor-suppressive activity. This SNP may have potential as a biomarker for TNBC risk and prognosis assessment.

Humans

Targeting FOXK2 in triple-negative breast cancer: Role of the P53/MCAS1/miR-211-5p regulatory axis.

Forkhead box K2 (FOXK2) is over-expressed in several human malignancies, yet how it is regulated triple-negative breast cancer (TNBC) remained unclear. We aimed to clarify whether FOXK2 drives TNBC progression, and elucidate the upstream molecular circuitry that controls FOXK2 abundance.&#xa0;FOXK2 mRNA and protein were quantified by qPCR and Western blot in 30 paired TNBC and adjacent tissues. Some assays assessed proliferation, migration and invasion after FOXK2 knockdown or overexpression. Bioinformatics predicted miR-211-5p targeting FOXK2 and lncRNA MCM3AP-AS1 (MCAS1) targeting miR-211-5p. RNA immunoprecipitation (RIP) and dual-luciferase assays validated these interactions. RNA pulldown, mass spectrometry and ChIP identified p53 binding to the MCAS1 promoter.&#xa0;FOXK2 was upregulated in TNBC tissues as opposed to the para-carcinoma tissues. FOXK2 silencing significantly reduced proliferation, migration and invasion, whereas overexpression accelerated these phenotypes. Mechanistically, MCAS1 acts as a sponge for miR-211-5p, ultimately protecting its target gene FOXK2 from degradation. Furthermore, employing RNA pulldown, mass spectrometry, ChIP, and luciferase reporter assays, our studies revealed a direct interaction between P53 and the promoter of MCAS1. This interaction resulted in the suppression of MCAS1 transcription. Clinical samples from TNBC patients further confirmed a correlation between FOXK2 expression and tumor size, lymphatic involvement, as well as the expression level of Ki-67.&#xa0;Our findings unveil a novel P53/MCAS1/miR-211-5p/FOXK2 regulatory axis that dictates TNBC aggressiveness. FOXK2 may sever as both a prognostic biomarker and a therapeutic target in TNBC.

Humans

Lysyl oxidase inhibition disrupts mitochondrial homeostasis to create vulnerability to ferroptosis in TNBC.

High metabolic heterogeneity and plasticity of triple-negative breast cancer (TNBC) contribute to therapy resistance, necessitating identification of therapeutic vulnerabilities. Here, we identify non-canonical functions of the extracellular matrix (ECM) remodeler, lysyl oxidase (LOX), in regulating glucose metabolism and mitochondrial homeostasis and show that inhibiting LOX generates targetable vulnerability to ferroptosis. Mechanistically, LOX interacts with PARKIN and its upstream kinase PINK1, which we identified as a substrate of LOX. LOX-mediated PINK1 oxidation suppresses PARKIN phosphorylation, stabilizing hypoxia-inducible factor 1-alpha (HIF-1&#x3b1;) and increasing glycolysis. Concomitantly, LOX inhibits PARKIN-mediated mitophagy and maintains mitochondria-ER contacts through VDAC1 stabilization, while the LOX-HSP90 complex promotes mitochondrial Ca2+ transport and ATP production. Inhibiting LOX suppresses glycolysis, disrupts mitochondrial dynamics, reduces OXPHOS and GPX4/FSP1, and induces compensatory DHODH activity. Our "one-two punch" approach combining LOX inhibition with clinical DHODH inhibitor suppresses tumor growth in vivo in chemo-free setting. Notably, LOX protein correlates with HIF-1&#x3b1;/GLUT1/GPX4 in TNBC patient tumors, supporting its clinical relevance.

Ferroptosis

Artificial intelligence-based tumour infiltrating lymphocyte quantification in patients with triple-negative breast cancer: an independent validation study.

BACKGROUND: Tumour-infiltrating lymphocytes (TILs) are a robust prognostic marker in patients with triple-negative breast cancer. Artificial intelligence (AI)-derived computational tools assessing TILs could improve efficiency, but require independent validation against clinical outcomes. We aimed to compare the prognostic performance of AI-derived TIL scores with pathologist-scored TILs in a large, prospectively collected dataset pooled from randomised controlled trials. METHODS: CATALINA was an independent, external validation study using prospectively collected long-term clinical outcome data pooled from seven randomised clinical trials conducted at multiple sites. We independently evaluated two previously validated AI pipelines that generate five computationally assessed tumour-infiltrating lymphocyte (cTIL) scores by masked, independent deployment of locked models. cTIL scores were correlated with the mean of the pathologist-scored stromal TILs (sTILs) in 220 digitised haematoxylin and eosin whole slide images in a cohort of patients with early-stage triple-negative or HER-2 positive breast cancer, previously scored by trained pathologists in a TIL-reproducibility study. Prognostic performance was assessed in a separate cohort of patients with early triple-negative breast cancer pooled from seven prospective, randomised adjuvant trials. Multivariable Cox regression models adjusted for clinicopathological factors and study heterogeneity assessed associations of cTIL score and sTIL score with invasive disease-free survival, distant disease-free survival, and overall survival. 5-year discrimination was estimated using time-dependent area under the receiver operating characteristic curve (AUC). FINDINGS: Individual data were collated from 1759 patients, of whom 1356 had complete clinicopathological data, pathologist sTIL scores, and cTIL scores available. Modest correlation (r 0&#xb7;375-0&#xb7;473) was observed between cTIL scores and the mean pathologist sTIL score. Both sTIL and cTIL were independently associated with 5-year invasive disease-free survival, distant disease-free survival, and overall survival after adjustment for clinicopathological factors (hazard ratio for invasive disease-free survival was 0&#xb7;73 [95% CI 0&#xb7;66-0&#xb7;82]; q<0&#xb7;0001, distant disease-free survival was 0&#xb7;70 [0&#xb7;61-0&#xb7;79]; q<0&#xb7;0001, and overall survival was 0&#xb7;72 [0&#xb7;63-0&#xb7;82]; q<0&#xb7;0001 for sTIL scores and 0&#xb7;80 [0&#xb7;73-0&#xb7;89]; q<0&#xb7;0001, 0&#xb7;77 [0&#xb7;69-0&#xb7;86]; q<0&#xb7;0001, and 0&#xb7;79 [0&#xb7;70-0&#xb7;88]; q=0&#xb7;0002, respectively, for percentage_lymphocyte scores). In models adjusted for clinicopathological variables and sTIL score, cTIL score did not maintain a statistically significant prognostic association. Both sTIL and cTIL scores improved the 5-year AUC over clinicopathological variables alone, while cTIL score did not significantly further improve AUC when combined with clinicopathological variables and sTIL score. INTERPRETATION: Two cTIL models deployed entirely without retraining or modification provided statistically significant prognostic information and improved risk discrimination compared with clinicopathological variables alone in this large, platform-based, independent validation study. Although cTIL score did not incrementally improve prognostication compared with models combining clinicopathological variables with sTIL score, these findings support the application of cTILs as a reproducible prognostic biomarker, particularly in settings where routine or widespread pathologist assessment is unavailable. FUNDING: Breast Cancer Research Foundation (USA).

Humans