Therapeutic Agent For Pancreatic Cancer Research Articles

A quinolinone derivative, vesnarinone (OPC-8212), significantly inhibits the in vitro and in vivo growth of human pancreatic cancer cell lines.

A quinolinone derivative, vesnarinone, has been used as a cardiotonic agent. Previous studies have demonstrated that vesnarinone has potent antitumor activity. The present study was designed to assess the antitumor effects of vesnarinone on human pancreatic cancer cell lines in vitro and in vivo. The in vitro effects of vesnarinone on the human pancreatic cancer cell lines (PANC-1, MIA PaCa-2 and BxPC-3) were assessed by the MTT assay, the Trypan blue dye exclusion test and the Matrigel invasion chamber assay. The inhibition of in vivo tumor growth was evaluated on two human pancreatic cancer xenografts (BxPC-3 and SPa-1) transplanted s.c. into nude mice. The dose of vesnarinone for 50% inhibition of cell growth in a 7 day culture ranged between 10 and 20 micrograms/ml as verified by the Trypan blue dye exclusion test. The dose for 50% cytotoxicity after a 3 day culture in the MTT assay was 32 micrograms/ml for PANC-1 and 30 micrograms/ml for BxPC-3, but 50% cytotoxicity for MIA PaCa-2 was not achieved by the maximal dose of vesnarinone (50 micrograms/ml). Nomalsky optic microscopy and acridine orange staining demonstrated the vacuolization and crater-like changes in the cell nucleus after vesnarinone treatment. Moreover, staining of an apoptosis marker (Le(y) protein) and nick end-labeling increased. Vesnarinone also inhibited cancer invasion in the Matrigel invasion chamber assay. In vivo, BxPC-3 and SPa-1 were s.c. transplanted into the nude mice, and vesnarinone (5 or 50 mg/kg) was daily administered orally for 21 days. In both lines, vesnarinone at 50 mg/kg achieved significant inhibition. The present study suggests that vesnarinone may be a new therapeutic agent for pancreatic cancer.

Inhibition of pancreatic adenocarcinoma cell growth by lovastatin

RAS protein (p21 ras) requires farnesyl (an intermediate of cholesterol synthesis) for activation. Activating mutations of K-ras gene have been detected in most human pancreatic adenocarcinomas. In the present study, the effect of lovastatin, an inhibitor of 3-hydroxy-3-methylglutaryl coenzyme A, the rate-limiting enzyme of cholesterol synthesis, on the growth of five pancreatic cancer cell lines (human-CAV, MIA Paca2, CAPAN2 and PANC1, and hamster-H2T) in vitro and of two cell lines (CAV and H2T) in vivo was examined. Inhibition of cell growth was observed with lovastatin doses at or above 2.5 μg/mL for H2T, CAV, MIA Paca2, and CAPAN2 or 10 μg/mL in PANC1. The H2T cell line was studied further to determine the reversibility of growth inhibition. Mevalonic acid (1 mmol/L) reversed lovastatin-induced inhibition of cell growth if it was added with lovastatin (2.5 μg/mL). Similarly, removal of lovastatin from the medium within 24 hours after treatment allowed recovery of cell growth. The effect of lovastatin on cell growth was irreversible after 48 hours of exposure. The survival fraction of H2T cells was markedly decreased by 1- or 24-hour exposure to 75 μg/mL but not to doses ranging from 0.5 to 60 μg/mL of lovastatin. Growth of pancreatic carcinoma xenografts (CAV and H2T) in nude mice was inhibited by a subcutaneous infusion of lovastatin (50 μg/h). These results indicate that mevalonic acid or a metabolite in the cholesterol synthesis pathway is necessary for growth of pancreatic cancer cells and suggest that lovastatin should be further examined as a potential therapeutic agent for pancreatic cancer.