The bisphosphonate incadronate inhibits intraperitoneal dissemination in an in vivo pancreatic cancer model

Pancreatic cancer is characterized by intraperitoneal dissemination and often by large volumes of ascites. Aminobisphosphonates exhibit potent antitumor effects and are currently being tested against human solid tumors. Several aminobisphosphonates inhibit cancer cell migration by preventing the activation of Rho through inhibition of the mevalonate pathway. We evaluated the ability of an aminobisphosphonate, incadronate, to inhibit the growth of disseminated pancreatic cancer in vivo. We established an in vivo pancreatic cancer model with i.p. carcinomatosis in nude mice. Incadronate administration started from the day of tumor inoculation, and reduced tumor burden and ascites accumulation. Further, we evaluated the effect of incadronate on the inhibition of pancreatic cancer cell proliferation, migration and invasion in vitro. Incadronate induced growth inhibition and apoptotic death of pancreatic cancer cells. It also inhibited migration presumably by preventing the activation of Rho by lysophosphatidic acid. Thus, the in vivo antitumor effect may result from the inhibition of cancer cell proliferation and migration. The potent effects of incadronate in reducing tumor burden and ascites suggest that it will be of value in regimens for the treatment of pancreatic cancer.