Assessment of anti-cancer effects of koenimbine on colon cancer cells.

Recent studies have highlighted the role of natural elements in reduction of cancer cell growth and apoptosis. Koenimbine, a natural product isolated from Murraya koenigii (L) Spreng is a substance with cytotoxic effects on cancer cells.The effects of koenimbine on HT-29 and SW48 colon cancer cells were evaluated by MTT and Annexin V assays. Expression levels of Wnt/β-catenin pathway genes were quantified by real time PCR.The IC50 values of koenimbine in HT-29 and SW48 was calculated to be 50 μg/ml based on the results of MTT assay. This value was 75 μg/ml in IEC-18 cells which were used as normal control. Annexin V assays revealed induction of cell apoptosis and necrosis in HT-29 and SW48 cells but not IEG18 cells by koenimbine. Koenimbin treatment resulted in significant down-regulation of CYCLD1 expression in SW48 cell line, but up-regulation of this gene in HT29 cell line. Expression of TBLR1, DKK1, GSK3B and β-catenin was significantly decreased after koenimbin treatment in HT-19 cell line. Moreover, expression of DKK1 and GSK3B was significantly decreased after koenimbin treatment in SW-40 cell line. TCF4 expression was not detected in any of cell lines either before or after treatment with koenimbin.The current in vitro study showed the cytotoxic effects of koenimbin on two colon cancer cell lines and the effects of this substance on expression of selected genes from Wnt-β catenin pathway. Future in vivo studies are needed before suggestion of this substance as an anti-cancer drug.