Induction of AHR Gene Expression in Colorectal Cancer Cell Lines by Cucurbitacin D, E, and I

Abstract

Aryl hydrocarbon receptor (AHR) is a ligand-activated transcription factor and its induction may result in suppressing of cell proliferation in colorectal cancer (CRC). Cucurbitacin D (CucD), E (CucE) and I (CucI) are plant derived metabolites that inhibit cancer cells. This study aimed to evaluate the possible potency of the cucurbitacins for activation of AHR expression in CRC cell lines SW-480 and HT-29. The MTT assay was used to find the LC50 value of the metabolites in the cell lines. Afterward, the cells incubated with the LC50 concentrations and AHR-mRNA expression assessed using RT-PCR. The LC50 values of CucD, CucE, and CucI were 4.5, 6.8, and 3.8 μM in HT-29 cell line and 35, 19, 17.5 μM in SW-480 cells respectively. The SW-480 cells were more resistant against Cucs in comparison with HT-29 cells and all three Cucs cause to more AHR-mRNA expression in HT-29 cells. CucE had the lowest effect on AHR-mRNA expression in the cell lines and CucI was a common metabolite for both HT-29 and SW-480 cells, which showed the lowest LC50 value (the highest toxicity) and the highest effect on AHR-mRNA expression. CucI may have a potential to be used as an activator of AHR expression in CRC studies.