Azelnidipine inhibits esophageal squamous cell carcinoma proliferation in vivo and in vitro by targeting MEK1/2

Epidemiological and mechanistic studies suggest that some US Food and Drug Administration (FDA)-approved drugs can reduce the incidence of cancer and inhibit tumor growth. Therefore, investigating FDA-approved drugs for cancer chemoprevention is a promising strategy. In this study, we screened FDA-approved drugs and found that azelnidipine, a Ca channel blocker widely used in the treatment of hypertension, inhibits the growth of esophageal squamous cell carcinoma (ESCC) in vitro and in vivo. We identified that MEK1/2 were direct targets of azelnidipine through pull-down assay and cellular thermal shift assay. Azelnidipine could suppress kinase activity of MEK1/2 through in vitro kinase assay. Hypophosphorylation of ERK1/2 decreased the levels of Cyclin D1/CDK6 in ESCC cells after azelnidipine treatment. More importantly, azelnidipine, like trametinib, inhibited the growth of ESCC in vivo. In conclusion, azelnidipine, a novel dual MEK1/2 inhibitor, exerted antitumor effects against ESCC cell lines and patient-derived xenograft in ESCC.