P-0208 Effect of α-Tocoferil Succinate in Two Different Cell Lines of Colorectal Adenocarcinoma

Abstract

ABSTRACT Introduction Colorectal cancer (CRC) is the third most common cancer worldwide with the highest incidence occurring in developed countries. The development of this cancer is progressive and occurs as a multistep genetic disease. A novel group of clinically interesting anticancer drugs has been a recent focus in the literature that holds substantial promise as selective anticancer drugs. These compounds, epitomized by α-tocopheryl succinate (α-TS), comprise redox-silent analogues of vitamin E which possess apoptogenic activity. Unlike the antioxidant α-tocopherol, α-TS can selectively induce apoptosis in malignant cells primarily via mitochondria-dependent apoptotic signaling. The purpose of this study is to evaluate, in vitro, the cytotoxic effect of α-TS in two human colorectal cancer cell lines (WiDr and C2BBe1 cells). Methods To attain this purpose, the cells WiDr and C2BBe1 were propagated at 37°C and 5% CO2 in DMEM medium supplemented with 5% fetal calf serum. Cells were incubated in absence and presence of different concentrations of α-TS and cell proliferation was evaluated after each 24h during 96 hours through the MTT (3-(4,5-dimethylthiazolyl-2)2,5-diphenyltetrazolium bromide) colorimetric assay and the respective half maximal inhibitory concentration (IC50) was calculated. Clonogenic assays were also performed to assess cell survival. The number of colonies was counted at eleventh day, and plate efficiency and survival factor were determined. Finally, cell viability and the type of cell death induced by α-TS were determined by flow cytometry using a dual staining with annexin-V and propidium iodide. Results The results obtained with MTT assay suggest that α-TS induces a decrease in cell proliferation in a dose and time-dependent way for both cell lines. However, WiDr cell line seems to be more sensitive to α-TS than C2BBe1 as it has lower IC50 values for each incubation time. Clonogenic assays revealed that, as the concentration of α-TS increases, the survival factor decreases. This behaviour was observed in both cell lines. Flow cytometry studies show that α-TS induces a decrease on cell viability and an increase in percentage of cells in apoptosis in a concentration-dependent manner, for both cell lines. These results suggest that apoptosis is a determinant pathway that confers antitumoral activity to this vitamin E analogue. Conclusion α-TS can effectively induce a decrease in proliferation, survival and viability in the studied colorectal cancer cells, being apoptosis one of the mechanisms by which TS suppresses malignant cells. This data show the potential of α-TS as an anti-neoplastic agent relevant for CRC treatment in clinical practice.