Hemoglobin induces colon cancer cell proliferation by release of reactive oxygen species

AIM: To study whether hemoglobin could amplify colon cancer cell proliferation via reactive oxygen species (ROS) production. METHODS: Colon cancer cell line HT-29 was grown in the conventional method using RPMI1640 media. The viability of the cells was measured using the colorimetric MTT [3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazo- lium bromide] assay after adding hemoglobin. We de- termined reactive oxygen species levels to be indicators of oxidative stress in HT 29 cell lines with and without hemoglobin and/or 5-fluorouracil (5-FU), 5’-deoxy-5-flu- orouridine (5-DFUR) using fluorometric dichlorofluorescin diacetate (DCFH-DA) assay. RESULTS: Cellular proliferation was increased with he- moglobin in a concentration-dependent manner. A signif- icant increment on ROS levels was found in HT 29 cells following hemoglobin incubation. The cytotoxic effects of 5-FU and 5-DFUR were significantly blunted by admin- istration of hemoglobin. There was a slight increase of peroxiredoxin 1, superoxide dismutase 1 concentration according to different hemoglobin concentrations. CONCLUSION: Hemoglobin has a cellular proliferative effect on HT-29 colon cancer cell line by production of ROS. Also, hemoglobin abates cytotoxic effects of che- motherapeutic agents such as 5-FU and 5-DFUR.