IER5 Promotes Ovarian Cancer Cell Proliferation and Peritoneal Dissemination

Epithelial ovarian cancer (OC), the most common type of OC, frequently harbors p53 mutations. In this study, we found that the immediate early response 5 gene (IER5), a p53 target gene, is overexpressed in OC cells. Importantly, OC cells found floating in the ascites had a higher expression of Ier5 than the parent strain, suggesting a role for IER5 in metastasis. Our previous research demonstrated that IER5 activates heat shock factor-1 (HSF1), a key transcription factor that regulates heat shock protein (HSP) genes by promoting the formation of a hypo-phosphorylated active form of HSF1. This activation of HSF1 by IER5 leads to the transcriptional activation of HSP genes, which help protect cells from stress. Here we showed that knockdown of Ier5 reduced the proliferation of OC cells as well as the induction of HSPs. These results indicate that the IER5-HSF1-HSP pathway contributes to the proliferation and peritoneal dissemination of OC cells.