Inhibition of hepatic metastasis from a human pancreatic adenocarcinoma (RWP-2) in the nude mouse by prostacyclin, forskolin, and ketoconazole.

Metastasis is a multistep phenomenon in which platelets appear to play an important role. This study examined several compounds for their effects on experimental hepatic metastasis and on human pancreatic tumor cell-platelet interactions. Prostacyclin (PGI2) and forskolin (stimulators of platelet adenylate cyclase) and ketoconazole (inhibitor of lipoxygenese and thromboxane synthetase) were used in order to investigate their effects on hepatic metastases from a human pancreatic tumor cell (RWP-2) in the nude mouse. The tumor cells were injected intrasplenically and the animals were divided into control, prostacyclin (PGI2 200 micrograms), forskolin (150 micrograms), and ketoconazole (180 micrograms) groups. All three drugs were administered intraperitoneally 30 minutes before and 24 hours after the tumor cell injections. Statistically significant differences were observed between control and treated groups in tumor surface area (P less than 0.001), percentage of liver surface area occupied by tumor (P less than 0.001), and number of tumor colonies (P less than 0.004 for prostacyclin, P less than 0.005 for forskolin, and P less than 0.001 for ketoconazole). These agents also strongly inhibited RWP-2-induced platelet aggregation in human platelet-rich plasma.