Wang Xiao-Qiang, Aka Juliette A, Li Tang, Xu Dan, Doillon Charles J, Lin Sheng-Xiang
Laboratory of Molecular Endocrinology and Oncology, Centre Hospitalier Universitaire de Québec Research Centre (CHUQ, CHUL), and Faculty of Medicine, Laval University, Quebec City, Quebec, G1 V 4G2, Canada; Center of Excellent for Molecular Diagnostics, Department of Pathology, Peking University Third Hospital, Beijing, 100091, China.
Laboratory of Molecular Endocrinology and Oncology, Centre Hospitalier Universitaire de Québec Research Centre (CHUQ, CHUL), and Faculty of Medicine, Laval University, Quebec City, Quebec, G1 V 4G2, Canada.
J Steroid Biochem Mol Biol. 2017 Sep;172:188-197. doi: 10.1016/j.jsbmb.2017.06.009. Epub 2017 Jun 20.
17beta-hydroxysteroid dehydrogenase type 7 (17β-HSD7) promotes breast cancer cell growth via dual-catalytic activity by modulating estradiol and DHT. Here, we clarified the expression pattern of 17β-HSD7 in postmenopausal luminal A type breast cancer with The Cancer Genome Atlas (TCGA) cohort. The impact of 17β-HSD7 inhibition on the proteome of MCF-7 cells was investigated and on cell apoptosis was revealed. MCF-7 cells were treated with an efficient inhibitor of 17β-HSD7 (INH7) or with vehicle, and a differential proteomics study was performed using two-dimensional (2D) gel electrophoresis followed by mass spectrometry and ingenuity pathway analysis (IPA). Cell apoptosis was analyzed by flow cytometry, followed by reverse transcription quantitative real-time PCR (RT-qPCR) and Western blot to investigate the expression of apoptosis-related genes. Our data showed 17β-HSD7 is amplified in primary and progressive breast cancer, inhibition of 17β-HSD7 in MCF-7 cells modulated 104 proteins primarily involved in cell death/survival, cell growth and DNA processing. The expression of 78kDa glucose-regulated protein (GRP78) and anti-apoptosis factor Bcl-2 were significantly suppressed via 17β-HSD7 inhibition with INH7, consequently induced MCF-7 cell apoptosis. However, INH7 treatment of T47D, another widely used epithelial ER+ breast cancer cell line, led to an up-regulation of GRP78 expression, resulting in a limited increase in apoptosis. These results suggest cell-specific effects of INH7 in the breast cancer, which is interesting for further study. An combinatory effect on apoptosis by INH7 and Letrozole (aromatase inhibitor) was further demonstrated in MCF-7. Down-regulation of GRP78 via 17β-HSD7 inhibition enhances cell apoptosis in response to Letrozole. This study highlights GRP78 as a key regulator related to 17β-HSD7 inhibition and effect. Taken together, results from the present study suggest a hypothesis that inhibition of 17β-HSD7 would be a complementary strategy to Letrozole by suppression of GRP78 in ER+ breast cancer. However, from a research perspective, further studies have to be carried out with more breast cancer cell lines as well as in vivo model to assess the efficacy of inhibitor combination.
17β-羟类固醇脱氢酶7型（17β-HSD7）通过调节雌二醇和双氢睾酮的双催化活性促进乳腺癌细胞生长。在此，我们利用癌症基因组图谱（TCGA）队列阐明了17β-HSD7在绝经后腔面A型乳腺癌中的表达模式。研究了17β-HSD7抑制对MCF-7细胞蛋白质组的影响，并揭示了其对细胞凋亡的影响。用17β-HSD7的有效抑制剂（INH7）或溶剂处理MCF-7细胞，采用二维（2D）凝胶电泳，随后进行质谱分析和 Ingenuity 通路分析（IPA），开展差异蛋白质组学研究。通过流式细胞术分析细胞凋亡，随后进行逆转录定量实时PCR（RT-qPCR）和蛋白质印迹，以研究凋亡相关基因的表达。我们的数据显示，17β-HSD7在原发性和进展性乳腺癌中扩增，抑制MCF-7细胞中的17β-HSD7可调节104种主要参与细胞死亡/存活、细胞生长和DNA加工的蛋白质。通过用INH7抑制17β-HSD7，78kDa葡萄糖调节蛋白（GRP78）和抗凋亡因子Bcl-2的表达被显著抑制，从而诱导MCF-7细胞凋亡。然而，用INH7处理另一种广泛使用的上皮性ER+乳腺癌细胞系T47D，导致GRP78表达上调，导致凋亡仅有限增加。这些结果表明INH7在乳腺癌中具有细胞特异性作用，这对于进一步研究很有意义。在MCF-7中进一步证明了INH7和来曲唑（芳香化酶抑制剂）对凋亡的联合作用。通过抑制17β-HSD7下调GRP78可增强对来曲唑的细胞凋亡反应。本研究强调GRP78是与17β-HSD7抑制及其作用相关的关键调节因子。综上所述，本研究结果提出了一个假设，即抑制17β-HSD7可能是通过抑制ER+乳腺癌中的GRP78来曲唑的补充策略。然而，从研究角度来看，必须使用更多乳腺癌细胞系以及体内模型进行进一步研究，以评估抑制剂联合的疗效。
