DOI: 10.36347/sajb.2018.v06i05.001

Pages: 394-398

Colorrectal cancer (CRC) is one of the cancers with more prevalence, incidence and mortality. The chemo resistance promotes its reappearance which has been related to a small subpopulation designated cancer stem cells (CSCs) associated to CD133 biomarker. Previous studies have related this chemoresistance to DNA repairing systems such as MGMT. The aim of this study is to compare the modulation of MGMT and CD133 expression in CSCs and CRC cells exposed to 5-FU chemotherapy. HCT15 resistant CRC cell line was used in the assays. Methylation status of both MGMT and CD133 promoters in HCT15 CRC cells was carried out by methylation-specific PCRs (MSP). CD133 and MGMT expression before and after 5-FU exposure was determined by reverse transcription-PCR. In addition, HCT15 cells were submitted to CSC enrichment medium to obtain CSCs. A comparative study of the expression of CD133 and MGMT expression was carried out between HCT15 cells and CSCs. Our results showed a CD133 increase in HCT15 resistant cells when were treated with 4xIC50 5FU. This increase maintained over time. By contrast, CD133 expression in CSCs decreased after 4 days in culture. Interestingly, only HCT15 cells treated with 5-FU showed a significant modulation of MGMT expression. Thus, both MGMT and CD133 biomarkers modulated in HCT15 colon cancer resistant cells in a different way depending on the use of high 5-FU doses or CSCs enrichment.