14 research outputs found
Estrogen Inhibits Renal Cell Carcinoma Cell Progression through Estrogen Receptor-Ī² Activation
<div><p>Renal cell carcinoma (RCC) originates in the lining of the proximal convoluted tubule and accounts for approximately 3% of adult malignancies. The RCC incidence rate increases annually and is twofold higher in males than in females. Female hormones such as estrogen may play important roles during RCC carcinogenesis and result in significantly different incidence rates between males and females. In this study, we found that estrogen receptor Ī² (ERĪ²) was more highly expressed in RCC cell lines (A498, RCC-1, 786-O, ACHN, and Caki-1) than in breast cancer cell lines (MCF-7 and HBL-100); however, no androgen receptor (AR) or estrogen receptor Ī± (ERĪ±) could be detected by western blot. In addition, proliferation of RCC cell lines was significantly decreased after estrogen (17-Ī²-estradiol, E2) treatment. Since ERĪ² had been documented to be a potential tumor suppressor gene, we hypothesized that estrogen activates ERĪ² tumor suppressive function, which leads to different RCC incidence rates between males and females. We found that estrogen treatment inhibited cell proliferation, migration, invasion, and increased apoptosis of 786-O (high endogenous ERĪ²), and ERĪ² siRNA-induced silencing attenuated the estrogen-induced effects. Otherwise, ectopic ERĪ² expression in A498 (low endogenous ERĪ²) increased estrogen sensitivity and thus inhibited cell proliferation, migration, invasion, and increased apoptosis. Analysis of the molecular mechanisms revealed that estrogen-activated ERĪ² not only remarkably reduced growth hormone downstream signaling activation of the AKT, ERK, and JAK signaling pathways but also increased apoptotic cascade activation. In conclusion, this study found that estrogen-activated ERĪ² acts as a tumor suppressor. It may explain the different RCC incidence rates between males and females. Furthermore, it implies that ERĪ² may be a useful prognostic marker for RCC progression and a novel developmental direction for RCC treatment improvement.</p> </div
Change in migration ability after ERĪ² downregulation or overexpression.
<p>(A) After transfection with siERĪ² or pcDNA3.1-ERĪ², the cells passing through the Transwell to the lower membrane were observed. (B) (C) Quantification of cells numbers that passed through the Transwell.</p
KaplanāMeier survival curve: the correlation between ERĪ² expression and RCC prognosis, assessed by univariate survival analysis.
<p>(A) Correlation analysis of ERĪ² expression and the overall survival of RCC (B) Correlation analysis of ERĪ² expression and DFS of RCC.</p
Expression of apoptotic signaling pathway downstream proteins in 786-O after ERĪ² downregulation and in A498 after ERĪ² overexpression.
<p>Expression of apoptotic signaling pathway downstream proteins in 786-O after ERĪ² downregulation and in A498 after ERĪ² overexpression.</p
Correlation between the risk factors of RCC and the expression of ERĪ².
*<p>Categorized as low (ā¤mean) and high (>mean) was separated at ERĪ² >35% positivity (high) and ERĪ² ā¤35% positivity (low).</p>ā <p>Based on the logistic regression model. Statistical significance (p<0.05) is shown in boldface. n.a.: not analyzed.</p><p>Abbrev: RCC: renal cell carcinoma, BRD: benign renal disease, OR: odds ratio, CI: confidence interval; ER: estrogen receptor.</p
Univariate and multivariate analyses of prognostic factors and RCC survival.
*<p>Categorized as low (ā¤mean) and high (>mean) was separated at ERĪ² >22% positivity (high) and ERĪ² ā¤22% positivity (low).</p>ā <p>Analyzed with the Cox hazard regression model. Statistical significance (p<0.05) is shown in boldface. n.a.: not analyzed.</p><p>Abbrev: RCC: renal cell carcinoma, OR: odds ratio, CI: confidence interval, OS: overall survival, DFS: disease-free survival, ER: estrogen receptor.</p
Firgure 6. Change in invasion ability after ERĪ² downregulation or overexpression.
<p>(A) After transfection with siERĪ² or pcDNA3.1-ERĪ², the cells passing through the Transwell to the lower membrane were observed. (B) (C) Quantification of cell numbers that passed through the Transwell.</p
Effect of estrogen on cell growth in the RCC cell line.
<p>In the CC cell lines 786-O, RCC-1, Caki-1, and ACHN, cell growth slowed down in the cells treated with estrogen (10 nM) compared with the control (ethanol). Only A498 was not affected by estrogen treatment. The experiments were repeated at least three times.</p
Expression of AR, ERĪ±, and ERĪ² in breast cancer and RCC cell lines, and the expression of ERĪ± and ERĪ² in kidney, RCC, and breast cancer tissue samples.
<p>(A) (B) In breast cancer cell lines, MCF-7 showed AR, ERĪ±, and ERĪ² expression, while HBL100 showed no ERĪ± expression and only low ERĪ² expression. In RCC cell lines, no AR expression was observed. Except A498, the RCC cell lines showed higher ERĪ² expression than the breast cancer cell lines. Expression of ERĪ² was the highest in 786-O. (C) IHC results for the observation of ERĪ± and ERĪ² expression in kidney, RCC, and breast cancer tissue samples. (C-a) Cytoplasm and nuclei of the kidney tissue showed high expression of ERĪ². (C-b) In RCC tissue, ERĪ² expression was mainly found in the cytoplasm. (C-c) Low expression of ERĪ² was observed in the cytoplasm of breast cancer tissue. (C-d) (C-e) No ERĪ± expression was found in the kidney or RCC tissue. (C-f) ERĪ± expressed in the nuclei of breast cancer tissue. Densitometry analyses for protein quantification were done using Image J 1.46x software (<a href="http://rsb.info.nih.gov/ij/download.html" target="_blank">http://rsb.info.nih.gov/ij/download.html</a>). The experiments were repeated at least three times. MCF7 expression was the baseline expression for the quantification comparison of ER. The results were analyzed with t-test.</p
Estrogen Enhances the Cell Viability and Motility of Breast Cancer Cells through the ERĪ±-ĪNp63-Integrin Ī²4 Signaling Pathway
<div><p>Estrogen induces ERĪ±-positive breast cancer aggressiveness via the promotion of cell proliferation and survival, the epithelial-mesenchymal transition, and stem-like properties. Integrin Ī²4 signaling has been implicated in estrogen/ERĪ±-induced tumorigenicity and anti-apoptosis; however, this signaling cascade poorly understood. ĪNp63, an N-terminally truncated isoform of the p63 transcription factor, functions as a transcription factor of integrinĪ²4 and therefore regulates cellular adhesion and survival. Therefore, the aim of the present study was to investigate the estrogen-induced interaction between ERĪ±, ĪNp63 and integrin Ī²4 in breast cancer cells. In ERĪ±-positive MCF-7 cells, estrogen activated ERĪ± transcription, which induced ĪNp63 expression. And ĪNp63 subsequently induced integrin Ī²4 expression, which resulted in AKT phosphorylation and enhanced cell viability and motility. Conversely, there was no inductive effect of estrogen on ĪNp63-integrinĪ²4-AKT signaling or on cell viability and motility in ERĪ±-negative MDA-MB-231 cells. ĪNp63 knockdown abolishes these estrogen-induced effects and reduces cell viability and motility in MCF-7 cells. Nevertheless, ĪNp63 knockdown also inhibited cell migration in MDA-MB-231 cells through reducing integrin Ī²4 expression and AKT phosphorylation. In conclusion, estrogen enhances ERĪ±-positive breast cancer cell viability and motility through activating the ERĪ±-ĪNp63-integrin Ī²4 signaling pathway to induce AKT phosphorylated activation. Those findings should be useful to elucidate the crosstalk between estrogen/ER signaling and ĪNp63 signaling and provide novel insights into the effects of estrogen on breast cancer progression.</p></div