Radiosensitizing potential of rutin against human colon adenocarcinoma HT-29 cells

The present study was focused at evaluating the potential of rutin to improve the radiotherapeutic index and thereby the cytotoxicity towards colon cancer cells.

HT-29 cells were pre-treated with rutin and the effect on cell proliferation was determined by MTT assay followed by exposure to radiation. After irradiation, experimental groups were sham control, rutin alone, radiation alone, rutin along with radiation-treated HT-29 cells.

Cytotoxicity study illustrated that treatment of HT-29 cells with different concentrations of rutin reduced cell proliferation in a dose- and time-dependent manner. After irradiation, the HT-29 cells revealed that the combined effect of 4 Gy radiation and rutin at 80 µM concentration showed a decrease in cell viability as compared to rutin‑alone treated and 4 Gy‑alone irradiated HT-29 cells. Furthermore, the increase in apoptotic cells, change from normal nuclei to abnormal nuclei, alterations in mitochondrial membrane potential, increase in DNA damage, increase in levels of lipid peroxidative markers, and decrease in antioxidant status were observed in 4 Gy‑ and rutin-treated group as compared to the other treated groups.

Combined effect of rutin and radiation in HT-29 cells leads to a more pronounced cell death rate. Thus, rutin exhibits radiosensitizing effects on HT-29 cells (Tab. 4, Fig. 8, Ref. 42).