Role of miRNAs in Sigmoid Colon Cancer: A Search for Potential Biomarkers

HLA class II polymorphisms as prognostic biomarkers for right and left-sided colon cancer

BACKGROUND

Colon cancer (CC) is one of the most common malignancies worldwide. Characterization of new prognostic biomarkers for right-sided CC (RCC) and left-sided CC (LCC) may contribute to improving early detection. An association of human leukocyte antigens class II (HLA-II) with the predisposition to CC was suggested.

AIM OF THE STUDY

We evaluated the association of DRB1 and DQB1 with the risk of LCC and RCC.

PATIENTS AND METHODS

Our study comprised 93 CC patients and 100 healthy controls. Genotyping of HLA class II alleles were performed by the Polymerase Chain Reaction Sequence-Specific Primers (PCR-SSP).

RESULTS

DRB1*03 was positively associated with CC. In contrast, DRB1*11, DRB1*13, DQB1*03, and DQB1*05 were negatively linked to CC. Haplotype analysis revealed that DRB1*04-DQB1*04 and DRB1*09-DQB1*02 were positive, while DRB1*01-DQB1*05, DRB1*04-DQB1*03, DRB1*07-DQB1*02, DRB1*11-DQB1*03, DRB1*11-DQB1*05, and DRB1*13-DQB1*06 were negatively associated with CC. For sigmoid CC, DRB1*13, DRB1*11, and DQB1*05 were negative, while DRB1*04-DQB1*02, and DRB1*07-DQB1*03 were positively associated. DRB1*03 and DRB1*04-DQB1*04 were positive, while DRB1*11 and DQB1*03 were negatively linked to RCC. According to the LCC, DRB1*07, DRB1*11, DQB1*03, DQB1*05, and DRB1*07-DQB1*02 were negative. In contrast, DRB1*09-DQB1*02 was positively associated with LCC. Stratified analysis revealed that DRB1*11 is associated with higher risk of metastasis in CC and sigmoid CC, and tolerance to treatment in RCC. DQB1*03 was associated with lymph-node invasion in CC.

CONCLUSION

DRB1 and DQB1 polymorphisms could be used as future biomarkers for the early detection of subjects at a higher risk of developing RCC and LCC, metastasis in sigmoid CC, and tolerance to treatment in RCC.

miR‑146b‑5p promotes colorectal cancer progression by targeting TRAF6

Increasing evidence highlights the multiple roles of microRNAs (miRs) in the tumorigenesis of colorectal cancer (CRC); however, the molecular mechanism, particularly the target of miR-146b-5p in CRC has not been fully elucidated. The present study aimed to elucidate the influence of miR-146b-5p via regulating tumor necrosis factor receptor-associated factor 6 (TRAF6) in CRC. The expression levels of miR-146b-5p and TRAF6 in CRC tissue and cells were determined by reverse transcription quantitative PCR and western blotting. Binding between miR-146b-5p and TRAF6 was examined using a dual luciferase reporter gene assay. The impact of miR-146b-5p and TRAF6 on proliferation and migration of CRC cells was determined using Cell Counting Kit-8 and Transwell assays, respectively. An animal model of CRC was established to determine the carcinogenic effect of the miR-146b-5p-TRAF6 axis. The results demonstrated that miR-146b-5p was highly expressed in CRC tissue samples compared with in normal adjacent tissue samples and in CRC cells compared with in the normal NCM460 cell line, whereas TRAF6 was expressed at low levels. Overexpression of miR-146b-5p decreased TRAF6 expression in CRC HT29 and SW620 cells. miR-146b-5p targeted and inhibited TRAF6 expression in CRC cells. Furthermore, transfection with a miR-146b-5p mimic promoted the proliferation, migration and invasion of CRC cells and tumor growth; however, these effects were abolished by TRAF6 overexpression. Transfection with a miR-146b-5p inhibitor suppressed the proliferation of CRC cells. Taken together, the results from the present study demonstrated that miR-146b-5p could enhance the initiation and tumorigenesis of CRC by targeting TRAF6. These results will help elucidate the mechanisms underlying CRC development and will facilitate the development of targeted therapy for CRC.