Effect of 3,4-dihydro-6-[4-(3,4-dimethoxybenzoyl)-1-piperazinyl]-2(1H)-quinolinone (vesnarinone) on the growth of gastric cancer cell lines

Vesnarinone (OPC-8212; 3,4-dihydro-6-[4-(3,4-dimethoxybenzoyl)-1-piperazinyl]-2(1H)-quinolinone) is a synthetic oral cardiotonic agent that has been used for the treatment of patients with congestive heart failure. Six days of treatment with 30 μg/ml of vesnarinone induced 20–80% growth inhibitions in five out of six gastric carcinoma cell lines examined. Cell cycle analysis revealed that the vesnarinone-sensitive TMK-1 gastric cancer cell line exhibited a significant G0–G1 arrest without evidence of apoptotic cell death induction after 48 h of treatment. Interestingly, this phenomenon was preceded by a marked reduction in the expression of cyclin A, D1 and E as well as cyclin-dependent kinase 2 (CDK2). On the other hand, no significant change was observed in the expression of p21Waf1/Cip1, p27Kip1 nor various growth factors and their receptor genes. Overall these results indicate that vesnarinone inhibits the growth of gastric cancer cells by down-regulating G1 cyclins and CDK2 to induce G0–G1 arrest through a pathway different from that of cyclin inactivation by p21Waf1/Cip1 or p27Kip1.