Document Type: Research Articles
Drug Discovery and Development Center, Office of Advanced Science and Technology, Thammasat University, Pathumthani, Thailand.
Center of Excellence in Pharmacology of Malaria and Cholangiocarcinoma, Chulabhorn International College of Medicine, Thammasat University, Pathumthani,Thailand.
Graduate Program in Bioclinical Sciences, Chulabhorn International College of Medicine, Thammasat University, Pathumthani, Thailand.
Objective: To investigate cytotoxic activity of ethyl-p-methoxycinnamate (EPMC) including its effect on p-glycoprotein (multidrug resistance-1: mdr-1 gene) in human cholangiocarcinoma cell. Methods: Cytotoxic activity of EPMC against human cholangiocarcinoma (CL-6), fibroblast (OUMS-36T-1F), and colon cancer (Caco-2) cell lines were assessed using MTT assay. Selectivity index (SI) was determined as the ratio of IC50 (concentration that inhibits cell growth by 50%) of EPMC in OUMS-36T-1F and that in CL-6 cell. Cell cycle arrest and apoptosis in CL-6 cells were investigated by flow cytometry and fluorescent microscopy. Effect of EPMC on mdr-1 gene expression in CL-6 and Caco-2 was determined by real-time PCR. Results: The median (95% CI) IC50 values of EPMC in CL-6, OUMS-36T-1F, and Caco-2 were 245.5 (243.1-266.7), 899.60 (855.8-966.3) and 347.0 (340.3-356.9) µg/ml, respectively. The SI value of the compound for the CL-6 cell was 3.70. EPMC at IC50 inhibited CL-6 cell division and induced apoptosis compared to untreated control. EPMC exposure did not induce mdr-1 gene expression in both CL-6 and Caco-2 cells. Conclusion: The results suggest the potential role of EPMC in cholangiocarcinoma with a low possibility of drug resistance induction.