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Project description:Epigenetic Silencing of TGFBI Confers Resistance to Trastuzumab in Human Breast Cancer
| PRJNA509689 | ENA
Project description:BACKGROUND:Acquired resistance to trastuzumab is a major clinical problem in the treatment of HER2-positive (HER2+) breast cancer patients. The selection of trastuzumab-resistant patients is a great challenge of precision oncology. The aim of this study was to identify novel epigenetic biomarkers associated to trastuzumab resistance in HER2+ BC patients. METHODS:We performed a genome-wide DNA methylation (450K array) and a transcriptomic analysis (RNA-Seq) comparing trastuzumab-sensitive (SK) and trastuzumab-resistant (SKTR) HER2+ human breast cancer cell models. The methylation and expression levels of candidate genes were validated by bisulfite pyrosequencing and qRT-PCR, respectively. Functional assays were conducted in the SK and SKTR models by gene silencing and overexpression. Methylation analysis in 24 HER2+ human BC samples with complete response or non-response to trastuzumab-based treatment was conducted by bisulfite pyrosequencing. RESULTS:Epigenomic and transcriptomic analysis revealed the consistent hypermethylation and downregulation of TGFBI, CXCL2, and SLC38A1 genes in association with trastuzumab resistance. The DNA methylation and expression levels of these genes were validated in both sensitive and resistant models analyzed. Of the genes, TGFBI presented the highest hypermethylation-associated silencing both at the transcriptional and protein level. Ectopic expression of TGFBI in the SKTR model suggest an increased sensitivity to trastuzumab treatment. In primary tumors, TGFBI hypermethylation was significantly associated with trastuzumab resistance in HER2+ breast cancer patients. CONCLUSIONS:Our results suggest for the first time an association between the epigenetic silencing of TGFBI by DNA methylation and trastuzumab resistance in HER2+ cell models. These results provide the basis for further clinical studies to validate the hypermethylation of TGFBI promoter as a biomarker of trastuzumab resistance in HER2+ breast cancer patients.
| S-EPMC6612099 | biostudies-literature
Project description:Resistance to tamoxifen is a clinically major challenge in breast cancer treatment. Although downregulation of estrogen receptor-alpha (ERα) is the dominant mechanism of tamoxifen resistance, the reason for ERα decrease during tamoxifen therapy remains elusive. Herein, we reported that Spalt-like transcription factor 2 (SALL2) expression was significantly reduced during tamoxifen therapy through transcription profiling analysis of 9 paired primary pre-tamoxifen-treated and relapsed tamoxifen-resistant breast cancer tissues. SALL2 transcriptionally upregulated ESR1 and PTEN through directly binding to the DNA promoters. By contrast, silencing SALL2 induced downregulation of ERα and PTEN and activated the Akt/mTOR signaling, resulting in estrogen-independent growth and tamoxifen resistance in ERα-positive breast cancer. Furthermore, hypermethylation of SALL2 promoter was found in tamoxifen-resistant breast cancer. Importantly, in vivo experiments showed that DNA methyltransferase inhibitor-mediated SALL2 restoration resensitized tamoxifen-resistant breast cancer to tamoxifen therapy. These findings shed light on the mechanism of SALL2 in regulation of ER and represent a potential clinical signature that can be used to categorize breast cancer patients who may benefit from co-therapy with tamoxifen and DNMT inhibitor.
| S-EPMC6895605 | biostudies-literature
Project description: Not available
| S-EPMC8899907 | biostudies-literature
Project description:Trastuzumab is a monoclonal targeted therapy widely used to treat human epidermal growth factor receptor 2 (HER2+) over expressed breast cancer which confers an aggressive cancer type and comprises ~25% of breast cancer. Trastuzumab yields improved breast cancer related outcomes, but survival benefits are in part offset by cardiotoxicity - as evidenced by 10-15% of patients develop cardiomyopathy and 2-4% develop congestive heart failure. Approximately 20-30% of patients have either temporary or permanent discontinuation of trastuzumab therapy due to its cardiotoxicity, raising concern for inadequate cancer treatment and recurrence. Current screening strategies for trastuzumab-induced cardiotoxicity rely on non-invasive imaging such as echocardiography, but conventional imaging techniques provide limited a priori risk stratification for cardiotoxicity. We have utilized patient-specific iPSC-CMs derived from HER2+ breast cancer patients with and without evidence of TIC as a model to better elucidate the mechanisms of Trastuzumab-indued cardiotoxicity.
2024-06-05 | GSE264120 | GEO
Project description:BACKGROUND: Resistance to humanized monoclonal erbB2/HER2 antibody, trastuzumab (Herceptin), has become a pivotal obstacle for targeted therapy of HER2-positive breast cancers. The activation of alternative growth factor receptors, in particular, the insulin-like growth factor 1 receptor (IGF1R), represents a common feature of trastuzumab-refractory cells; however, the underlying mechanism remains elusive. METHODS: Trastuzumab-resistant breast cancer SKBr-3 cells were generated by long-term in vitro culture of SKBr-3 cells in the presence of trastuzumab. Among the differentially expressed microRNAs (miRNAs) screened by microarray analysis, candidate miRNA(s) predicted to target IGF1R was studied for its role in conferring trastuzumab resistance. The mechanism underlying decreased expression of IGF1R-targeted miRNA in refractory cells was also addressed. RESULTS: miR-375, which was downregulated and predicted to target IGF1R in trastuzumab-resistant HER2-positive breast cancer cells, could indeed inhibit the cellular luciferase activity in a reporter construct containing the 3'-UTR of IGF1R. Overexpression of miR-375 restored the sensitivity of cells to trastuzumab, while inhibition of miR-375 conferred trastuzumab resistance on HER2-positive breast cancer cells. Blockade of DNA methylation and histone deacetylation restored the expression of miR-375 in trastuzumab-resistant cells. A reverse correlation between the levels of miR-375 and IGF1R was validated in clinical breast cancers. CONCLUSIONS: Epigenetic silencing of miR-375 causes the upregulation of IGF1R, which at least partially underlies trastuzumab resistance of breast cancer cells. Our study has implications for miR-375 as a potential target in combination with trastuzumab for treating HER2-positive breast cancers.
| S-EPMC3974046 | biostudies-literature
Project description:HER2 receptor tyrosine kinase (encoded by the ERBB2 gene) is overexpressed in approximately 25% of all breast cancer tumors (HER2-positive breast cancers). Resistance to HER2-targeting therapies is partially due to the loss of HER2 expression in tumor cells during treatment. However, little is known about the exact mechanism of HER2 downregulation in HER2-positive tumor cells. Here, by analyzing publicly available genomic data we investigate the hypothesis that epithelial-mesenchymal transition (EMT) abrogates HER2 expression by epigenetic silencing of the ERBB2 gene as a mechanism of acquired resistance to HER2-targeted therapies. As result, HER2 expression was found to be positively and negatively correlated with the expression of epithelial and mesenchymal phenotype marker genes, respectively. The ERBB2 chromatin of HER2-high epithelial-like breast cancer cells and HER2-low mesenchymal-like cells were found to be open/active and closed/inactive, respectively. Decreased HER2 expression was correlated with increased EMT phenotype, inactivated chromatin and lower response to lapatinib. We also found that induction of EMT in the HER2-positive breast cancer cell line BT474 resulted in downregulated HER2 expression and reduced trastuzumab binding. Our results suggest that ERBB2 gene silencing by epigenetic regulation during EMT may be a mechanism of de novo resistance of HER2-positive breast cancer cells to trastuzumab and lapatinib.
| S-EPMC8472246 | biostudies-literature
Project description:We sequenced untreated BT474 cells, BT474 cells treated for three days with trastuzumab or trastuzumab + pertuzumab, as well as two BT474-derived trastuzumab-resistant pools and two BT474-derived trastuzumab + pertuzumab resistant pools. Resistant pools were generated by culturing BT474 cells in gradually increasing doses of trastuzumab and trastuzumab + pertuzumab over the course of several months and continually maintained in drug.
2020-01-26 | GSE121105 | GEO
Project description:Human breast cancer SKBr-3 cells selected with trastuzumab for 6 month compared with parental SKBr-3 cells; Goal was to screen for microRNAs involved in development of trastuzumab resistance. Human breast cancer SKBr-3 cells were continuously cultured in the presence ofM-BM- 5M-BM-5g/ml trastuzumab for 6 months, and the resulting alive cells were regarded as trastuzumab-resistant. Total RNAs were prepared from these cells and cells cultured in parallel in control media, and were subjected to hybridization on the miRCURY LNA Array (Exiqon, version 11.0).
2013-05-25 | E-GEOD-47011 | biostudies-arrayexpress
Project description:To assess pathologic complete response (pCR), clinical response, feasibility, safety, and potential predictors of response to preoperative trastuzumab plus vinorelbine in patients with operable, human epidermal growth factor receptor 2 (HER2)-positive breast cancer. EXPERIMENTAL DESIGN: 48 patients received preoperative trastuzumab and vinorelbine weekly for 12 weeks. Single and multigene biomarker studies were done in an attempt to identify predictors of response. RESULTS: 8 of 40 (20%) patients achieved pCR (95% confidence interval, 9-36%). Of 9 additional patients recruited for protocol-defined toxicity analysis, 8 were evaluable; 42 of 48 (88%) patients had clinical response (16 patients, clinical complete response; 26 patients, clinical partial response). T(1) tumors more frequently exhibited clinical complete response (P = 0.05) and showed a trend to exhibit pCR (P = 0.07). 5 (13%) patients experienced grade 1 cardiac dysfunction during preoperative treatment. Neither HER2 nor estrogen receptor status changed significantly after exposure to trastuzumab and vinorelbine. RNA profiling identified three top-level clusters by unsupervised analysis. Tumors with extremes of response [pCR (n = 3) versus nonresponse (n = 3)] fell into separate groups by hierarchical clustering. No predictive genes were identified in pCR tumors. Nonresponding tumors were more likely to be T(4) stage (P = 0.02) and express basal markers (P < 0.00001), growth factors, and growth factor receptors. Insulin-like growth factor-I receptor membrane expression was associated with a lower response rate (50% vs 97%; P = 0.001). CONCLUSIONS: Preoperative trastuzumab plus vinorelbine is active and well tolerated in patients with HER2-positive, operable, stage II/III breast cancer. HER2-overexpressing tumors with a basal-like phenotype, or with expression of insulin-like growth factor-I receptor and other proteins involved in growth factor pathways, are more likely to be resistant to this regimen. harri-00137 Assay Type: Gene Expression Provider: Affymetrix Array Designs: HG-U133_Plus_2 Organism: Homo sapiens (ncbitax)
2015-06-25 | E-GEOD-70233 | biostudies-arrayexpress