Indoxyl sulfate has selective anticancer potential against colon cancer cells

There are number of reports about anti-cancer activity of indole derivatives and some of them such as Vinblastine have been used in clinic evaluations. In this study, we investigated the role of indoxyl sulfate (IS), an indole derivative, for its selective anti-cancer activity on colon cancer cells. Whether indoxyl sulfate has any harmful effect on normal colonic cells has also been studied. IS treatment on HCT-116 and HT-29 human epithelial adenocarcinoma cell lines led decrease in cell proliferation efficiency, cell viability and ATP content was observed. Colon cancer cells showed 10% increase in cell apoptosis in comparison to control. Due to IS treatment, cell morphology got distorted, cell number found decreased, intracellular vesicles formed and cells were found floated in the media. Cells also showed loss in membrane integrity and decrease in colony forming ability. Indoxyl sulfate also caused cell cycle to cease at G2/M phase. During animal study, balb/c mice were treated with 100mM of indoxyl sulfate to check colonic inflammation, if any, by IS administration and level of inflammatory cytokines IL-17A, IL-1β and TNF-α were studied. The change in the level of inflammatory cytokines after IS treatment was found statistically insignificant, hence IS was found not causing inflammation. Histological study also showed no sign of inflammation after IS treatment. No significant change in the length of intestine and spleen was noted after IS treatment. In conclusion, we found IS has selective deleterious and anticancer effect on colon cancer cells and does not cause harm to normal colonic cells.