MDM2 regulates estrogen receptor ? and estrogen responsiveness in breast cancer cells.
Ontology highlight
ABSTRACT:
SUBMITTER: Kim K
PROVIDER: S-EPMC3069690 | biostudies-literature | 2011 Apr
REPOSITORIES: biostudies-literature
Publications
MDM2 regulates estrogen receptor α and estrogen responsiveness in breast cancer cells.
Kim Kyounghyun K Burghardt Robert R Barhoumi Rola R Lee Syng-Ook SO Liu Xinyi X Safe Stephen S
Journal of molecular endocrinology 20110215 2
Murine double minute clone 2 (MDM2) is a multifunctional protein, which modulates nuclear receptor-mediated transactivation. In this study, we show that MDM2 significantly enhanced estrogen receptor α (ERα) and ERα/specificity protein-mediated transactivation in MCF-7 and ZR-75 breast cancer cells. This was demonstrated by both MDM2 overexpression and knockdown experiments by RNA interference. ERα interacted with wild-type MDM2 and deletion mutants of MDM2 containing amino acids 1-342 (C-termina ...[more]
Similar Datasets
Project description:Progesterone and estrogen are important drivers of breast cancer proliferation. Herein, we probed estrogen receptor-α (ER) and progesterone receptor (PR) cross-talk in breast cancer models. Stable expression of PR-B in PR-low/ER+ MCF7 cells increased cellular sensitivity to estradiol and insulin-like growth factor 1 (IGF1), as measured in growth assays performed in the absence of exogenous progestin; similar results were obtained in PR-null/ER+ T47D cells stably expressing PR-B. Genome-wide microarray analyses revealed that unliganded PR-B induced robust expression of a subset of estradiol-responsive ER target genes, including cathepsin-D (CTSD). Estradiol-treated MCF7 cells stably expressing PR-B exhibited enhanced ER Ser167 phosphorylation and recruitment of ER, PR and the proline-, glutamate- and leucine-rich protein 1 (PELP1) to an estrogen response element in the CTSD distal promoter; this complex co-immunoprecipitated with IGF1 receptor (IGFR1) in whole-cell lysates. Importantly, ER/PR/PELP1 complexes were also detected in human breast cancer samples. Inhibition of IGF1R or phosphoinositide 3-kinase blocked PR-B-dependent CTSD mRNA upregulation in response to estradiol. Similarly, inhibition of IGF1R or PR significantly reduced ER recruitment to the CTSD promoter. Stable knockdown of endogenous PR or onapristone treatment of multiple unmodified breast cancer cell lines blocked estradiol-mediated CTSD induction, inhibited growth in soft agar and partially restored tamoxifen sensitivity of resistant cells. Further, combination treatment of breast cancer cells with both onapristone and IGF1R tyrosine kinase inhibitor AEW541 was more effective than either agent alone. In summary, unliganded PR-B enhanced proliferative responses to estradiol and IGF1 via scaffolding of ER-α/PELP1/IGF1R-containing complexes. Our data provide a strong rationale for targeting PR in combination with ER and IGF1R in patients with luminal breast cancer.
| S-EPMC4112172 | biostudies-literature
Project description:Fatty acid synthase (FASN), the key enzyme for endogenous synthesis of fatty acids, is overexpressed and hyperactivated in a biologically aggressive subset of sex steroid-related tumors, including breast carcinomas. Using pharmacological and genetic approaches, we assessed the molecular relationship between FASN signaling and estrogen receptor alpha (ER?) signaling in breast cancer. The small compound C75, a synthetic slow-binding inhibitor of FASN activity, induced a dramatic augmentation of estradiol (E2)-stimulated, ER?-driven transcription. FASN and ER? were both necessary for the synergistic activation of ER? transcriptional activity that occurred following co-exposure to C75 and E2: first, knockdown of FASN expression using RNAi (RNA interference) drastically lowered (>100 fold) the amount of E2 required for optimal activation of ER?-mediated transcriptional activity; second, FASN blockade synergistically increased E2-stimulated ER?-mediated transcriptional activity in ER?-negative breast cancer cells stably transfected with ER?, but not in ER?-negative parental cells. Non-genomic, E2-regulated cross-talk between the ER? and MAPK pathways participated in these phenomena. Thus, treatment with the pure antiestrogen ICI 182?780 or the potent and specific inhibitor of MEK/ERK, U0126, was sufficient to abolish the synergistic nature of the interaction between FASN blockade and E2-stimulated ER? transactivation. FASN inhibition suppressed E2-stimulated breast cancer cell proliferation and anchorage-independent colony formation while promoting the reduction of ER? protein. FASN blockade resulted in the increased expression and nuclear accumulation of the cyclin-dependent kinase inhibitors p21WAF1/CIP1 and p27Kip1, two critical mediators of the therapeutic effects of antiestrogen in breast cancer, while inactivating AKT, a key mediator of E2-promoted anchorage-independent growth. The ability of FASN to regulate E2/ER? signaling may represent a promising strategy for anticancer treatment involving a new generation of FASN inhibitors.
| S-EPMC5337623 | biostudies-literature
Project description:Poly(ADP-ribose) polymerase-1 (PARP-1) has gained considerable attention as a target for therapeutic inhibitors in breast cancers. Previously we showed that PARP-1 localizes to active gene promoters to regulate histone methylation and RNA polymerase II activity (Pol II), altering the expression of various tumor-related genes. Here we report a role for PARP-1 in estrogen-dependent transcription in estrogen receptor alpha (ERα)-positive (ER+) breast cancers. Global nuclear run-on and sequencing analyses functionally linked PARP-1 to the direct control of estrogen-regulated gene expression in ER+ MCF-7 breast cancer cells by promoting transcriptional elongation by Pol II. Furthermore, chromatin immunoprecipitation sequencing analyses revealed that PARP-1 regulates the estrogen-dependent binding of ERα and FoxA1 to a subset of genomic ERα binding sites, promoting active enhancer formation. Moreover, we found that the expression levels of the PARP-1- and estrogen-coregulated gene set are enriched in the luminal subtype of breast cancer, and high PARP-1 expression in ER+ cases correlates with poor survival. Finally, treatment with a PARP inhibitor or a transcriptional elongation inhibitor attenuated estrogen-dependent growth of multiple ER+ breast cancer cell lines. Taken together, our results show that PARP-1 regulates critical molecular pathways that control the estrogen-dependent gene expression program underlying the proliferation of ER+ breast cancer cells. IMPLICATIONS: PARP-1 regulates the estrogen-dependent genomic binding of ERα and FoxA1 to regulate critical gene expression programs by RNA Pol II that underlie the proliferation of ER+ breast cancers, providing a potential therapeutic opportunity for PARP inhibitors in estrogen-responsive breast cancers.
| S-EPMC8492518 | biostudies-literature
Project description:BackgroundApproximately 70% of all breast cancers express the estrogen receptor, and are regulated by estrogen. While the ovaries are the primary source of estrogen in premenopausal women, most breast cancer is diagnosed following menopause, when systemic levels of this hormone decline. Estrogen production from androgen precursors is catalyzed by the aromatase enzyme. Although aromatase expression and local estrogen production in breast adipose tissue have been implicated in the development of primary breast cancer, the source of estrogen involved in the regulation of estrogen receptor-positive (ER+) metastatic breast cancer progression is less clear.MethodsBone is the most common distant site of breast cancer metastasis, particularly for ER+ breast cancers. We employed a co-culture model using trabecular bone tissues obtained from total hip replacement (THR) surgery specimens to study ER+ and estrogen receptor-negative (ER-) breast cancer cells within the human bone microenvironment. Luciferase-expressing ER+ (MCF-7, T-47D, ZR-75) and ER- (SK-BR-3, MDA-MB-231, MCF-10A) breast cancer cells were cultured directly on bone tissue fragments or in bone tissue-conditioned media, and monitored over time with bioluminescence imaging (BLI). Bone tissue-conditioned media were generated in the presence vs. absence of aromatase inhibitors, and testosterone. Bone tissue fragments were analyzed for aromatase expression by immunohistochemistry.ResultsER+ breast cancer cells were preferentially sustained in co-cultures with bone tissues and bone tissue-conditioned media relative to ER- cells. Bone fragments analyzed by immunohistochemistry revealed expression of the aromatase enzyme. Bone tissue-conditioned media generated in the presence of testosterone had increased estrogen levels and heightened capacity to stimulate ER+ breast cancer cell proliferation. Pretreatment of cultured bone tissues with aromatase inhibitors, which inhibited estrogen production, reduced the capacity of conditioned media to stimulate ER+ cell proliferation.ConclusionsThese results suggest that a local estrogen signaling axis regulates ER+ breast cancer cell viability and proliferation within the bone metastatic niche, and that aromatase inhibitors modulate this axis. Although endocrine therapies are highly effective in the treatment of ER+ breast cancer, resistance to these treatments reduces their efficacy. Characterization of estrogen signaling networks within the bone microenvironment will identify new strategies for combating metastatic progression and endocrine resistance.
| S-EPMC5688761 | biostudies-literature
Project description:BackgroundBRK is, a non-receptor tyrosine kinase, overexpressed in approximately 85% of human invasive ductal breast tumors. It is not clear whether BRK expression correlates with breast cancer subtypes, or the expression has prognostic or diagnostic significance. Herein, we investigated the correlation of BRK with any breast cancer subtypes and clinicopathological significance of BRK expression in breast cancer.MethodsIn this study, we examined BRK expression in 120 breast tumor samples and 29 breast cancer cell lines to explore the positive correlation between BRK and the expression of ER?. We used immunohistochemistry, RT-PCR, and immunoblotting to analyse our experimental samples.ResultWe demonstrate that estrogen induces BRK gene and protein expression in ER+ breast cancer cells. Over-expression of ER? in the ER-negative breast cancer cell line increased BRK expression, and knock-down of ESR1 in MCF7 cells reduced BRK levels. Further, we provide evidence that BRK is regulated by ER? signaling and the presence of ER antagonists (tamoxifen and fulvestrant) reduce the expression of BRK in ER-positive breast cancer cells. Finally, we demonstrate that the overall survival of ER-positive breast cancer patients is poor when their cancers express high levels of BRK.ConclusionOur data indicate that BRK is a prognostic marker for ER+ breast cancers and provide a strong rationale for targeting BRK to improve patients' survival.
| S-EPMC6335685 | biostudies-literature
Project description:The proper level of estrogen-estrogen receptor (ER) signaling is important for the maintenance of epithelial homeostasis in the breast. In a previous study we demonstrated that ATBF1, which has been suggested as a tumor suppressor in breast cancer, inhibited estrogen-mediated cell proliferation by selectively competing with AIB1 for binding to the ER. However, the expression of ATBF1 mRNA was shown to positively correlate with ER in breast cancer specimens. We, therefore, examined whether estrogen regulates ATBF1. We demonstrated that estrogen up-regulated the transcription of ATBF1, which was mediated by the direct binding of the ER onto the ATBF1 promoter, and that a half-estrogen-responsive element in the ATBF1 promoter was essential for ER direct binding. Furthermore, we found that estrogen at lower levels increased, but at higher levels decreased the expression of ATBF1 protein, which involved the degradation of ATBF1 protein by the estrogen-responsive proteasome system. ATBF1 protein levels fluctuate with estrogen levels. Although lower levels of estrogen increased ATBF1 protein expression, ATBF1 still inhibited cell proliferation caused by lower levels of estrogen. These findings not only reveal an autoregulatory feedback loop between ATBF1 and estrogen-ER signaling but also suggest that ATBF1 plays a role in both the maintenance of breast epithelial homeostasis and breast tumorigenesis caused by elevated estrogen levels.
| S-EPMC3077589 | biostudies-literature
Project description:Triple Negative Breast Cancer (TNBC) has the worst prognosis among all breast cancers, and survival in patients with recurrence is rarely beyond 12 months due to acquired resistance to chemotherapy, which is the standard of care for these patients. Our hypothesis is that Estrogen Receptor β1 (ERβ1) increases response to chemotherapy but is opposed by ERβ4, which it preferentially dimerizes with. The role of ERβ1 and ERβ4 in influencing chemotherapy sensitivity has never been studied before. CRISPR/CAS9 was used to truncate ERβ1 Ligand Binding Domain (LBD) and knock down the exon unique to ERβ4. We show that the truncated ERβ1 LBD in a variety of mutant p53 TNBC cell lines, where ERβ1 ligand dependent function was inactivated, had increased resistance to Paclitaxel, whereas the ERβ4 knockdown cell line was sensitized to Paclitaxel. We further show that ERβ1 LBD truncation, as well as treatment with ERβ1 antagonist 2-phenyl-3-(4-hydroxyphenyl)-5,7-bis(trifluoromethyl)-pyrazolo[1,5-a] pyrimidine (PHTPP), leads to increase in the drug efflux transporters. Hypoxia Inducible Factors (HIFs) activate factors involved in pluripotency and regulate the stem cell phenotype, both in normal and cancer cells. Here we show that the ERβ1 and ERβ4 regulate these stem cell markers like SOX2, OCT4, and Nanog in an opposing manner; and we further show that this regulation is mediated by HIFs. We show the increase of cancer cell stemness due to ERβ1 LBD truncation is attenuated when HIF1/2α is knocked down by siRNA. Finally, we show an increase in the breast cancer stem cell population due to ERβ1 antagonist using both ALDEFLUORTM and SOX2/OCT4 response element (SORE6) reporters in SUM159 and MDA-MB-231 cell lines. Since most TNBC cancers are ERβ4 positive, while only a small proportion of TNBC patients are ERβ1 positive, we believe that simultaneous activation of ERβ1 with agonists and inactivation of ERβ4, in combination with paclitaxel, can be more efficacious and yield better outcome for chemotherapy resistant TNBC patients.
| S-EPMC10058198 | biostudies-literature
Project description:Estrogen receptor ? (ER?) is an essential element regulating mammary gland development and it contributes to breast cancer development and progression. Most of the ER-negative breast cancers display more aggressive clinical behaviors and are resistant to antiestrogen therapies. In addition, many ER-negative tumors show insensitivity to many chemotherapeutic drugs and radiotherapy, although mechanisms underlying this phenotype are less clear.We conducted immunohistochemistry on 296 cases of breast cancer tissues using a variety of antibodies. On the basis of the clinical data, we conducted siRNA knockdown to study the role of ER? on ATM expression in breast cancer cell lines. Furthermore, we used antisense oligonucleotides against micro RNAs (miRNA) or miRNA overexpression plasmids to study the role of miR-18a and -106a on ATM expression. Finally we used in situ hybridization to assess miR-18a and -106a expression in breast cancer tissues.We found that in ER-negative breast cancer tissues, expression of the ATM kinase, a critical DNA damage-response protein, is aberrantly upregulated. We also found that the locoregional recurrence rate after radiotherapy positively correlates with ATM expression. On the cellular level, we showed that ER?, but not ER?, negatively regulates ATM expression. Furthermore, we identified that ER? activates miR-18a and -106a to downregulate ATM expression. We also showed that miR-18a and -106a were significantly underexpressed in ER-negative breast cancer tissues.We reveal a novel mechanism involving ER? and miR-18a and -106a regulation of ATM in breast cancer.
| S-EPMC3778106 | biostudies-literature
Project description:Progesterone and estrogen are important drivers of breast cancer proliferation. Herein, we probed estrogen receptor-α (ER) and progesterone receptor (PR) cross-talk in breast cancer models. Stable expression of PR-B in PR-low/ER+ MCF7 cells increased cellular sensitivity to estradiol and insulin-like growth factor 1 (IGF1), as measured in growth assays performed in the absence of exogenous progestin; similar results were obtained in PR-null/ER+ T47D cells stably expressing PR-B. Genome-wide microarray analyses revealed that unliganded PR-B induced robust expression of a subset of estradiol-responsive ER target genes, including cathepsin-D (CTSD). Estradiol-treated MCF7 cells stably expressing PR-B exhibited enhanced ER Ser167 phosphorylation and recruitment of ER, PR and the proline-, glutamate- and leucine-rich protein 1 (PELP1) to an estrogen response element in the CTSD distal promoter; this complex co-immunoprecipitated with IGF1 receptor (IGFR1) in whole-cell lysates. Importantly, ER/PR/PELP1 complexes were also detected in human breast cancer samples. Inhibition of IGF1R or phosphoinositide 3-kinase blocked PR-B-dependent CTSD mRNA upregulation in response to estradiol. Similarly, inhibition of IGF1R or PR significantly reduced ER recruitment to the CTSD promoter. Stable knockdown of endogenous PR or onapristone treatment of multiple unmodified breast cancer cell lines blocked estradiol-mediated CTSD induction, inhibited growth in soft agar and partially restored tamoxifen sensitivity of resistant cells. Further, combination treatment of breast cancer cells with both onapristone and IGF1R tyrosine kinase inhibitor AEW541 was more effective than either agent alone. In summary, unliganded PR-B enhanced proliferative responses to estradiol and IGF1 via scaffolding of ER-α/PELP1/IGF1R-containing complexes. Our data provide a strong rationale for targeting PR in combination with ER and IGF1R in patients with luminal breast cancer.
2015-03-15 | GSE45643 | GEO
Project description:The clinical significance of progesterone receptor (PgR) expression in estrogen receptor-negative (ER-) breast cancer is controversial. Herein, we systemically investigate the clinicopathologic features, molecular essence, and endocrine responsiveness of ER-/PgR+/HER2- phenotype.Four study cohorts were included. The first and second cohorts were from the Surveillance, Epidemiology, and End Results database (n?=?67,932) and Fudan University Shanghai Cancer Center (n?=?2,338), respectively, for clinicopathologic and survival analysis. The third and fourth cohorts were from two independent publicly available microarray datasets including 837 operable cases and 483 cases undergoing neoadjuvant chemotherapy, respectively, for clinicopathologic and gene-expression analysis. Characterized genes defining subgroups within the ER-/PgR+/HER2- phenotype were determined and further validated.Clinicopathologic features and survival outcomes of the ER-/PgR+ phenotype fell in between the ER+/PgR+ and ER-/PgR- phenotypes, but were more similar to ER-/PgR-. Among the ER-/PgR+ phenotype, 30% (95% confidence interval [CI] 17-42%, pooled by a fixed-effects method) were luminal-like and 59% (95% CI 45-72%, pooled by a fixed-effects method) were basal-like. We further refined the characterized genes for subtypes within the ER-/PgR+ phenotype and developed an immunohistochemistry-based method that could determine the molecular essence of ER-/PgR+ using three markers, TFF1, CK5, and EGFR. Either PAM50-defined or immunohistochemistry-defined basal-like ER-/PgR+ cases have a lower endocrine therapy sensitivity score compared with luminal-like ER-/PgR+ cases (P <0.0001 by Mann-Whitney test for each study set and P <0.0001 for pooled standardized mean difference in meta-analysis). Immunohistochemistry-defined basal-like ER-/PgR+ cases might not benefit from adjuvant endocrine therapy (log-rank P?=?0.61 for sufficient versus insufficient endocrine therapy).The majority of ER-/PgR+/HER2- phenotype breast cancers are basal-like and associated with a lower endocrine therapy sensitivity score. Additional studies are needed to validate these findings.
| S-EPMC4595063 | biostudies-literature