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Project description:The transcriptional activity of the TEAD4 trascription factor requires co-activators. In this study we found that the expression of the TEAD coactivator VGLL1 is repressed in estrogen receptor positive breast cancer but upon resistance to endocrine threapies VGLL1 is expressed to high levels. To elucidate the importance of the coactivator VGLL1 in breast cancer cells resistant to endocrine therapies and to identify the VGLL1 target genes, we performed ChIP-seq for VGLL1 in MCF7 breast cancer cells resistant to fulvestrant (FULVR) and ChiP-seq for TEAD4 in FULVR cells and the isogenic MCF7 cells.
2023-12-05 | GSE216525 | GEO
Project description:To investigate the function of VGLL1 in breast cancer and its role in the resistance to endocrine therapies we generated stable MCF7 cells overexpressing VGLL1 using CRISPR/Cas9 Synergistic Activation Mediator (SAM) method (MCF7 ActCas9-VGLL1 cells). MCF7 ActCas9-VGLL1 cells were also cultured in the presence of fulvestrant 100nmM or 1µM to develop fulvestrant resistant cells (MCF7 ActCas9-VGLL1-FULVR) and RNA-seq was performed in the different cell lines.
2023-12-05 | GSE216528 | GEO
Project description:To identify VGLL1 target genes we performed RNA-seq following siRNA-mediated VGLL1 downregulation in FULVR cells.
2023-12-05 | GSE216527 | GEO
Project description:To investigate if the drug verteporfin can inhibit VGLL1 co-transcriptional activity in Fulvestrant resistant breast cancer cells.
2023-12-05 | GSE216526 | GEO
Project description:BackgroundAmong women, breast cancer is the leading cause of cancer-related death worldwide. Estrogen receptor α-positive (ERα+) breast cancer accounts for 70% of all breast cancer subtypes. Although ERα+ breast cancer initially responds to estrogen deprivation or blockade, the emergence of resistance compels the use of more aggressive therapies. While ERα is a driver in ERα+ breast cancer, ERβ plays an inhibitory role in several different cancer types. To date, the lack of highly selective ERβ agonists without ERα activity has limited the exploration of ERβ activation as a strategy for ERα+ breast cancer.MethodsWe measured the expression levels of ESR1 and ESR2 genes in immortalized mammary epithelial cells and different breast cancer cell lines. The viability of ERα+ breast cancer cell lines upon treatments with specific ERβ agonists, including OSU-ERb-12 and LY500307, was assessed. The specificity of the ERβ agonists, OSU-ERb-12 and LY500307, was confirmed by reporter assays. The effects of ERβ agonists on cell proliferation, cell cycle, apoptosis, colony formation, cell migration, and expression of tumor suppressor proteins were analyzed. The expression of ESR2 and genes containing ERE-AP1 composite response elements was examined in ERα+ human breast cancer samples to determine the correlation between ESR2 expression and overall survival and that of putative ESR2-regulated genes.ResultsIn this study, we demonstrate the efficacy of highly selective ERβ agonists in ERα+ breast cancer cell lines and drug-resistant derivatives. ERβ agonists blocked cell proliferation, migration, and colony formation and induced apoptosis and S and/or G2/M cell-cycle arrest of ERα+ breast cancer cell lines. Also, increases in the expression of the key tumor suppressors FOXO1 and FOXO3a were noted. Importantly, the strong synergy between ERβ agonists and ERα antagonists suggested that the efficacy of ERβ agonists is maximized by combination with ERα blockade. Lastly, ESR2 (ERβ gene) expression was negatively correlated with ESR1 (ERα gene) and CCND1 RNA expression in human metastatic ERα+/HER2- breast cancer samples.ConclusionOur results demonstrate that highly selective ERβ agonists attenuate the viability of ERα+ breast cancer cell lines in vitro and suggest that this therapeutic strategy merits further evaluation for ERα+ breast cancer.
| S-EPMC9097292 | biostudies-literature
Project description:Estrogen receptor-positive (ER+) breast cancer is the most common form of breast cancer. Antiestrogens were the first therapy aimed at treating this subtype, but resistance to these warranted the development of a new treatment option. CDK4/6 inhibitors address this problem by halting cell cycle progression in ER+ cells, and have proven to be successful in the clinic. Unfortunately, both intrinsic and acquired resistance to CDK4/6 inhibitors are common. Numerous mechanisms of how resistance occurs have been identified to date, including the activation of prominent growth signaling pathways, the loss of tumor-suppressive genes, and noncanonical cell cycle function. Many of these have been successfully targeted and demonstrate the ability to overcome resistance to CDK4/6 inhibitors in preclinical and clinical trials. Future studies should focus on the development of biomarkers so that patients likely to be resistant to CDK4/6 inhibition can initially be given alternative methods of treatment.
| S-EPMC8625090 | biostudies-literature
Project description:Resistance is an obstacle to endocrine therapy for breast cancer. We measured levels of hypoxia-inducible factor (HIF)-1? in 52 primary breast cancer patients before and after receiving neoadjuvant endocrine therapy with letrozole for at least 3 months. Pre-treatment levels of HIF-1? were associated with negative clinical outcome. Furthermore, levels of HIF-1? were increased in post-treatment residual tumors compared with those in pre-treatment biopsy samples. In animal studies, xenografts stably expressing HIF-1? were resistant to endocrine therapy with fulvestrant compared with the effects in control xenografts. Additionally, HIF-1? transcription was inhibited by zoledronic acid, a conventional drug for the treatment of postmenopausal osteoporosis, and was accompanied by a marked inhibition of the RAS/MAPK/ERK1/2 pathway. HIF-1? is a determinant of resistance to endocrine therapy and should be considered as a potential therapeutic target for overcoming endocrine resistance in estrogen receptor (ER)-positive breast cancer. In addition, zoledronic acid may overcome endocrine resistance in ER-positive human breast cancer by targeting HIF-1? transcription through inhibition of the RAS/MAPK/ERK1/2 pathway. Clinical studies on the administration of zoledronic acid as a second line treatment in patients who failed endocrine therapy should be considered to improve therapeutic outcomes in breast cancer patients.
| S-EPMC4496173 | biostudies-literature
Project description:Estrogen receptor-positive (ER(+)) breast cancers adapt to hormone deprivation and become resistant to antiestrogen therapy. Here, we performed deep sequencing on ER(+) tumors that remained highly proliferative after treatment with the aromatase inhibitor letrozole and identified a D189Y mutation in the inhibitory SH2 domain of the SRC family kinase (SFK) LYN. Evaluation of 463 breast tumors in The Cancer Genome Atlas revealed four LYN mutations, two of which affected the SH2 domain. In addition, LYN was upregulated in multiple ER(+) breast cancer lines resistant to long-term estrogen deprivation (LTED). An RNAi-based kinome screen revealed that LYN is required for growth of ER(+) LTED breast cancer cells. Kinase assays and immunoblot analyses of SRC substrates in transfected cells indicated that LYN(D189Y) has higher catalytic activity than WT protein. Further, LYN(D189Y) exhibited reduced phosphorylation at the inhibitory Y507 site compared with LYN(WT). Other SH2 domain LYN mutants, E159K and K209N, also exhibited higher catalytic activity and reduced inhibitory site phosphorylation. LYN(D189Y) overexpression abrogated growth inhibition by fulvestrant and/or the PI3K inhibitor BKM120 in 3 ER(+) breast cancer cell lines. The SFK inhibitor dasatinib enhanced the antitumor effect of BKM120 and fulvestrant against estrogen-deprived ER(+) xenografts but not LYN(D189Y)-expressing xenografts. These results suggest that LYN mutations mediate escape from antiestrogens in a subset of ER(+) breast cancers.
| S-EPMC4348968 | biostudies-literature
Project description:BackgroundPreviously, we reported that Wnt5a-positive breast cancer can be classified as estrogen receptor (ER)-positive breast cancer; its prognosis is worse than that of Wnt5a-negative breast cancer. This study aimed to investigate the mechanisms underlying the poor prognosis in Wnt5a-positive breast cancer patients.MethodsIn total, 151 consecutive ER-positive breast cancer patients who underwent resection between January 2011 and February 2014 were enrolled. DNA microarray and pathway analyses were conducted using MCF-7 cells stably expressing Wnt5a [MCF-7/Wnt5a (+)]. Based on the outcomes, cell viability/drug sensitivity assays, and mutation analysis were performed using cell cultures and breast cancer tissues. The relationship between Wnt5a and the PI3K-AKT-mTOR signaling pathway was also examined.ResultsThe relapse-free survival rate in patients with Wnt5a-positive breast cancer was significantly lower than that in patients with Wnt5a-negative breast cancer (P = 0.047). DNA microarray data suggest that only the cytochrome P450 (CYP) pathway was significantly upregulated in MCF-7/Wnt5a (+) cells (P = 0.0440). Additionally, MCF-7/Wnt5a (+) cells displayed reduced sensitivity to the metabolic substrates of CYP, tamoxifen (P < 0.001), paclitaxel (P < 0.001), and cyclophosphamide (P < 0.001). Of note, PIK3CA mutations were not associated with the expression of Wnt5a in breast cancer tissue and culture cells.ConclusionsIn ER-positive breast cancer, Wnt5a upregulates the CYP metabolic pathway and suppresses tamoxifen, paclitaxel, and cyclophosphamide resistance, all of the three, standard treatment methods for ER-positive breast cancer. Wnt5a is thus potentially involved in the poor prognosis of ER-positive breast cancer independently of the PI3K-AKT-mTOR signaling pathway.
| S-EPMC8354951 | biostudies-literature
Project description:We found by RNA seq analysis that the expression of the cyclin D1 gene, the classic target of estrogen-stimulated transcription through an AP1 response element, negatively correlated with that of ERβ/ESR2 as measured using Spearman correlation coefficient (rho = -0.45, p = 0.005). ERβ/ESR2 expression was also negatively correlated with that of ERα/ESR1 (rho = -0.35, p = 0.033). However, ERβ/ESR2 mRNA expression positively correlated with that of IGFBP4 (rho = 0.58, p < 0.001) and CXCL12 (rho = 0.54, p < 0.001). The univariate Cox proportional hazards estimate for overall survival by ESR2 expression was 0.54 (95% CI 0.06, 5.22), suggesting a positive trend that did not reach statistical significance in this numerically limited cohort .
2022-05-18 | GSE198545 | GEO