Cyclosporine A inhibits colorectal cancer proliferation probably by regulating expression levels of c-Myc, p21(WAF1/CIP1) and proliferating cell nuclear antigen.

The present study investigated the role of calcineurin (CaN) in the proliferation of human colorectal cancers. CaN activity and protein expression were increased in human colorectal cancers. Nuclear transcription factor NFAT, a physiological substrate for CaN, was activated in human colon cancer specimen as well as in the human colon cancer cell lines. CaN inhibitor cyclosporine A (CsA) reduced cell growth in these cell lines. CsA decreased the expressions of c-Myc and the proliferating cell nuclear antigen (PCNA) but also increased p21(WAF1/CIP1) expression. Our results suggest that CaN promotes colorectal cancer proliferation probably by regulating levels of c-Myc, p21(WAF1/CIP1), and PCNA.