OSW-1

OSBP/ORP4.

OSW-1 has a strong inhibitory effect on colon carcinoma cells with low cytotoxicity on normal cells. The anti-proliferative effects of OSW-1 on SW480 and LoVo colon carcinoma cells are characterized by measuring cell viability using the CCK8 assay, and compared the results with other clinical anticancer agents. SW480 and LoVo cell lines are derived from a Dukes' stage B colon carcinoma and a colon carcinoma metastatic nodule, which represent non-metastatic and metastatic carcinomas, respectively. OSW-1 exhibits not only extremely strong anticancer activity in SW480 and LoVo cell lines with an IC ₅₀ of nanomolar concentration, but is also more potent than other anticancer agents by 10-100 times, with a lower cytotoxic effect on normal epithelial cells. These results indicate that OSW-1 has a powerful anticancer effect, but lower cytotoxic effect on normal cells.

To ascertain whether or not OSW-1 is as effective in vivo, a nude mouse model inoculated by LoVo cells is adopted, in which OSW-1 treatment is performed when tumors became palpable. The results show that the size of tumors in treated mice is smaller on average than control mice. The significant difference is observed from the 15-17 th day following treatment, and this difference is gradually increased until the animals are sacrificed. Compared with the control group, the tumor weight of the OSW-1-treated group significantly decreases (P<0.05). Additionally, no apparent side effects are observed in OSW-1-treated mice. These results demonstrate that OSW-1 has powerful effects on suppressing colon tumor growth without significant side effects in vivo.