Role of Wnt/β-catenin, Wnt/c-Jun N-terminal kinase and Wnt/Ca(2+) pathways in cisplatin-induced chemoresistance in ovarian cancer

The aim of the present study was to explore the expression of Wnt signaling proteins β-catenin, c-Jun N-terminal kinase (JNK) and Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) in ovarian cancer cells, and assess the correlation between this expression and cisplatin-induced chemoresistance. SKOV3 ovarian carcinoma cells and SKOV3/DDP (cisplatin resistant) cells were treated with cisplatin in the absence or presence of a Wnt signaling activator (CHIR-99021, glycogen synthase kinase 3β inhibitor) or inhibitor (XAV-939, tankyrase inhibitor). Following incubation for 48 h, cell viability, proliferation and cytotoxicity were measured using a sensitive colorimetric cell counting kit. Expression levels of β-catenin, JNK and CaMKII were detected by western blot and immunofluorescence staining. The results of the current study identified that β-catenin and JNK expression levels were significantly higher (P<0.01 and P<0.05 respectively), while CaMKII expression was lower (P>0.05), in SKOV3/DDP cells compared with SKOV3 cells. Moreover, following treatment with 20 µM cisplatin, reduced expression of β-catenin and JNK (P<0.05 and P<0.01 respectively), and increased expression of CaMKII (P<0.01), was observed in SKOV3 and SKOV3/DPP cell lines. Furthermore, inhibition of β-catenin signaling by XAV-939 effectively reversed cisplatin chemoresistance in SKOV3/DDP cells. Similarly, XAV-939 downregulated JNK expression (P<0.001), but upregulated CaMKII expression (P<0.001), in SKOV3/DDP cells. In conclusion, abnormal activation of Wnt/β-catenin and Wnt/JNK signaling pathways in ovarian cancer cells promotes cisplatin resistance, while the Wnt/Ca(2+) signaling pathway reduces cisplatin resistance. This indicates that β-catenin, JNK and CaMKII are potential therapeutic targets in chemoresistant ovarian cancers.