Blocking NFATc3 ameliorates azoxymethane/dextran sulfate sodium induced colitis-associated colorectal cancer in mice via the inhibition of inflammatory responses and epithelial-mesenchymal transition.

Ulcerative colitis-associated colorectal cancer (UC-CRC) is the most serious complication of ulcerative colitis (UC). Nuclear factor of activated T cells 3 (NFATc3) is participated in inflammation and cancer. In this study, we investigated the effects of NFATc3 on experimental UC-CRC in vivo and in vitro, and explored the underlying mechanisms. Administration of azoxymethane (AOM) and dextran sulfate sodium (DSS) induced UC-CRC model in C57BL/6 mice. Body weight was monitored weekly. Colon tissues were harvested at week 14. We examined changes in the histopathology, inflammatory cytokines, carcinogenesis factors, and epithelial-mesenchymal transition (EMT) markers in colon tissues. We found that NFATc3 expression was significantly up-regulated in AOM/DSS treated mice compared with control. Mice lacking NFATc3 showed decreased tumor number and size, decreased mucosal damage, and increased survival rate. Moreover, down-regulation of NFATc3 could inhibit the proliferation and EMT of UC-CRC, decrease the levels of pro-inflammatory cytokines, reduce the colonic infiltration by neutrophils and macrophages, and suppress the activation of P38 and JNK signal pathway in mice. In In vitro experiments, silencing NFATc3 suppressed the proliferation and EMT of CRC cells, and reduced the activation of P38 and JNK. In addition, miR-370-3p could bind to NFATc3. Down-regulation of miR-370-3p promoted proliferation and EMT of CRC cells, while silencing NFATc3 could reverse these effects. In conclusion, NFATc3 was involved in the pathogenesis of experimental UC-CRC and NFATc3 knockdown ameliorated experimental UC-CRC progression via the inhibition of inflammatory responses and EMT. NFATc3 mediated the inhibitory effects of miR-370-3p on CRC cells proliferation and EMT. Targeting NFATc3 may be effective in treating UC-CRC.