Activation of p38-MAPK by CXCL4/CXCR3 axis contributes to p53-dependent intestinal apoptosis initiated by 5-fluorouracil

Abstract

Chemotherapy-induced mucositis (CIM) is a major does limiting side-effect of chemoagents such as 5-fluorouracil (5-FU). Molecules involved in this disease process are still not fully understood. We proposed that the homeostatically regulated genes during CIM may participate in the disease. A cluster of such genes were previously identified by expression gene-array from the mouse jejunum in 5-FU-induced mucositis model. Here, we report that CXCL4 is such a homeostatically regulated gene and serves as a new target for the antibody treatment of CIM. CXCL4 and its receptor CXCR3 were confirmed at both the gene and protein levels to be homeostatically regulated during 5-FU-induced mucositis. Using of CXCL4 neutralizing monoclonal antibody (CXCL4mab) decreased the incidence, severity, and duration of the chemotherapy-induced diarrhea, the major symptom of CIM, in a 5-FU mouse CIM model. Mechanistically, CXCL4mab reduced the apoptosis of the crypt epithelia by suppression of the 5-FU-induced expression of p53 and Bax through its receptor CXCR3. The downstream signaling pathway of CXCL4 in activation of the epithelial apoptosis was identified in an intestinal epithelial cell line (IEC-6). CXCL4 activated the phosphorylation of p38 MAPK, which mediated the stimulated expression of p53 and Bax, and resulted in the ultimate activation of Caspase-8, -9, and -3. Taken together, activation of CXCL4 expression by 5-FU in mice participates in 5-FU-induced intestinal mucositis through upregulation of p53 via activation of p38-MAPK, and CXCL4mab is potentially beneficial in preventing CIM in the intestinal tract.

Keywords: :

• CXCL4
• chemotherapy
• intestinal mucositis
• apoptosis
• p53
• p38

Disclosure of Potential Conflicts of Interest

No potential conflicts of interest were disclosed.

Author’s Contributions

W.H. and Y.Y. developed the concept for the studies; W.H., Y.Y., and J.G. designed the experiments; Jin G. and J.G. participated in the production of recombinant human CXCL4 protein; X.W. and Y.Z. developed methods to produce the CXCL4 antibody and performed in vivo analysis of CXCL4 function; J.G., Jin G., L.Q., X.W., and Y.Z. performed in vitro assays; H.Y. performed the tumor experiments of CXCL4mab; and W.H., Y.Y., and J.G. wrote the manuscript.

Acknowledgments

This work was supported by the National Natural Science Foundation of China (grant 81373467/H3108, 81173113/H3109, and 81273573/H3108).