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JNK confers 5-fluorouracil resistance in p53-deficient and mutant p53-expressing colon cancer cells by inducing survival autophagy.

Research paper by Xinbing X Sui, Na N Kong, Xian X Wang, Yong Y Fang, Xiaotong X Hu, Yinghua Y Xu, Wei W Chen, Kaifeng K Wang, Da D Li, Wei W Jin, Fang F Lou, Yu Y Zheng, Hong H Hu, Liu L Gong, Xiaoyun X Zhou, et al.

Indexed on: 16 Apr '14Published on: 16 Apr '14Published in: Scientific Reports



Abstract

Deficiency or mutation in the p53 tumor suppressor gene commonly occurs in human cancer and can contribute to disease progression and chemotherapy resistance. Currently, although the pro-survival or pro-death effect of autophagy remains a controversial issue, increasing data seem to support the idea that autophagy facilitates cancer cell resistance to chemotherapy treatment. Here we report that 5-FU treatment causes aberrant autophagosome accumulation in HCT116 p53(-/-) and HT-29 cancer cells. Specific inhibition of autophagy by 3-MA, CQ or small interfering RNA treatment targeting Atg5 or Beclin 1 can potentiate the re-sensitization of these resistant cancer cells to 5-FU. In further analysis, we show that JNK activation and phosphorylation of Bcl-2 are key determinants in 5-FU-induced autophagy. Inhibition of JNK by the compound SP600125 or JNK siRNA suppressed autophagy and phosphorylation of c-Jun and Bcl-2 but increased 5-FU-induced apoptosis in both HCT116 p53(-/-) and HT29 cells. Taken together, our results suggest that JNK activation confers 5-FU resistance in HCT116 p53(-/-) and HT29 cells by promoting autophagy as a pro-survival effect, likely via inducing Bcl-2 phosphorylation. These results provide a promising strategy to improve the efficacy of 5-FU-based chemotherapy for colorectal cancer patients harboring a p53 gene mutation.