Transcriptome of 17β-hydroxysteroid dehydrogenase type 2 plays both hormone-dependent and hormone-independent roles in MCF-7 breast cancer cells

Breast cancer is a major cause of cancer-related death for women in western countries. 17β-Hydroxysteroid dehydrogenases (17β-HSDs) play important roles in the last step of sex-hormone activation and the first step of sex-hormone inactivation. 17β-HSD2 is responsible for oxidizing the sex hormones. We used microarray technology to analyze the effect of 17β-HSD2 on the MCF-7 cell transcript profile after knocking down 17β-HSD2. Five hundred forty-two genes were regulated 1.5-fold or higher after treatment with 17β-HSD2 siRNA. Knocking down 17β-HSD2 interrupted nucleosome assembly. Pathway-Act-Network analysis showed that the MAPK and apoptosis signaling pathways were most regulated. In the gene-gene interaction network analysis, UGT2B15, which is involved in hormone metabolism, was the most regulated core gene. FOS, GREB1, and CXCL12 were the most regulated genes, and CXCL12 was related to tumor migration. Following 17β-HSD2 knock-down, the cell viability decreased to 75.9%. The S-phase percentage decreased by 19.4%, the Q2-phase percentage in cell apoptosis testing increased by 1.5 times, and cell migration decreased to 66.0%. These results were consistent with our gene chip analysis and indicated that 17β-HSD2 plays both hormone-dependent and hormone-independent enzymatic roles. In-depth investigations of this enzyme on the genomic level will help clarify its related molecular mechanisms.