CDK2 and colonic neoplasm: Meclizine has been shown to induce apoptosis in a dose-dependent manner in human colon cancer cell lines, i.e., COLO 205 and HT 29, but its mechanism of action differs from that of loratadine, as it induces cell cycle arrest in the G0/G1 phase, which is associated with increased levels of p53 and p21 proteins and decreased activity of cyclin-dependent kinases 2 and 4 (CDK2 and CDK4, respectively).