Abstract
BACKGROUND: Resistance to poly (ADP-ribose) polymerase (PARP) inhibitors (PARPis) remain a major challenge in ovarian cancer (OC) treatment. However, the underlying mechanism of PARPi resistance is still poorly characterized. Increasing evidence has proven that lymphocyte cytosolic protein 1 (LCP1) promotes tumor progression. The JAK2/STAT3 signaling pathway plays an important role in increasing tumor metastatic ability and chemoresistance in cancer by promoting epithelial - mesenchymal transition (EMT). METHODS: We established an olaparib-resistant OC cell line and studied its toxicologic effects through cell survival, Transwell, colony formation, western blotting and flow cytometry assays. RNA sequencing and screening were then performed to identify genes associated with olaparib resistance. Lymphocyte cytosolic protein 1 (LCP1) was found to be overexpressed in olaparib-resistant OC cells. RESULTS: The inhibition of cell survival and promotion of cell apoptosis induced by olaparib in parental cells were significantly attenuated in olaparib-resistant cells. LCP1 was upregulated in olaparib-resistant cells compared with parental OC cells. Moreover, we found that the protein levels of JAK2/STAT3 signaling pathway components and EMT markers were increased in olaparib-resistant cells. Overexpression of LCP1 increased olaparib resistance in OC cells, and knockdown of LCP1 attenuated olaparib resistance. The changes in the protein levels of JAK2/STAT3 signaling pathway members and EMT markers between the cell types were similar to the changes in the levels of LCP1. CONCLUSIONS: These findings indicate that LCP1 expression may play an important role in the resistance of OC to olaparib by activating the JAK2/STAT3 signaling pathway and EMT. LCP1 could be a potential therapeutic target for patients with OC who are resistant to olaparib. Our study provides a new mechanism of olaparib resistance.