Chemotherapy mediates intestinal injury via p53/p53 upregulated modulator of apoptosis (PUMA) signaling pathway

OBJECTIVE: The aim of this study was to investigate the potential mechanism and signaling pathway involved in chemotherapy-induced intestinal mucosal injury (CIMI), which is a common physiopathological problem in patients with cancer. METHODS: For the in vivo experiment, mice received intraperitoneal injection of 5-fluorouracil (5-FU) at a dose of 75 mg/kg/day for 1, 3 or 5 days. Villus height and crypt depth of the small intestine, cell apoptosis and proliferation were then examined to determine the extent of CIMI. The expressions of Akt, p53, PUMA and p21 were evaluated both in vivo in mice models and in vitro in the IEC-6 and HCT116 cell lines. RESULTS: After 5-FU therapy both the intestinal villus height (275.93 mu m vs 164.52 mu m, P < 0.001) and crypt depth (64.13 mu m vs 42.48 mu m, P < 0.001) were decreased. The apoptotic index was greatly increased from 0.32% to 15.84% (P < 0.001) and proliferation was suppressed (63.58% vs 39.15%, P < 0.001). Additionally, p53 expression was significantly increased in the intestinal crypt along with the expressions of PUMA and p21. Western blot showed that the administration of 5-FU induced p53/PUMA-mediated apoptosis and upregulated p21 expression to suppress cell proliferation. CONCLUSION: Chemotherapy might mediate intestinal injury via p53/PUMA-mediated apoptotic signaling and the suppression of proliferation in response to p21.