The mechanism by which the transcription factors inhibit the miRNA expression in ovarian cancer chemoresistance is unclear. The present study investigated the mechanism underlying the transcriptional repression of miR-134 in chemoresistant serous epithelial ovarian cancer. The results demonstrate that NF-κB1, c-Rel, and ELK1 are involved as transcription factors in repressing miR-134 expression in paclitaxel-resistant ovarian cancer cells. Knockdown of these transcription factors led to increased miR-134 expression, resulting in increased apoptosis and inhibition of proliferation in SKOV3-TR30 cells. NF-κB1, c-Rel, and ELK1 mRNA expression was upregulated in chemoresistant specimens and negatively correlated with miR-134 expression. Kaplan-Meier analysis revealed that high nuclear expressions of NF-κB1, c-Rel, ELK1 were significantly associated with short survival in serous epithelial ovarian cancer patients. Finally, TAB1 was identified as a functional target of miR-134, and the expression of TAB1 was increased by the transcription factors of NF-κB1, c-Rel, and ELK1 via miR-134. Taken together, these results provide an insight into the mechanism of repressed miR-134 expression in chemoresistance of serous epithelial ovarian cancer.
Keywords: miR-134; miRNA gene regulation; ovarian cancer; paclitaxel resistance; transcription factor.