Association of HMGA2 Polymorphisms with Glioma Susceptibility in Chinese Children

Association of deletion polymorphism rs10573247 in the HMGA2 gene with the risk of breast cancer: bioinformatic and experimental analyses

BACKGROUND

The high mobility group A2 (HMGA2) gene is expressed extensively during early embryonic development but is inactivated in adulthood, and it is also reactivated in various benign and malignant tumors, including breast cancer. We first assessed the potential functional significance of the unstudied deletion polymorphism rs10573247 at the 3'UTR of HMGA2 on miRNA binding using bioinformatic tools, and subsequently, the association between this polymorphism and breast cancer susceptibility was investigated.

MATERIALS AND METHODS

We applied the RNAhybrid tool to predict the functional effects of polymorphism rs10573247 located within the 3' UTR of the HMGA2 gene on miRNA binding. Then, following DNA extraction, 141 breast cancer patients and 123 healthy controls were genotyped for polymorphism rs10573247 using RFLP-PCR with the restriction enzyme Eam1104I.

RESULTS

Our bioinformatic data have shown that polymorphism rs10573247 is located in the region that serves as a potential target site for eight miRNAs binding. Among them, miR-3125 exhibited decreased binding affinity for the allele delTT (MFE = -21.8) when compared to the allele TT (MFE = -23.9), but miR-4476 increased binding affinity for the allele delTT (MFE = -22.4) compared to the allele TT (MFE = -22.2). In addition, our results showed that the genotype TT/delTT (p = 0.005) and the genotype delTT/delTT (p = 0.029) were significantly associated with an increased risk of developing breast cancer compared to the genotype TT/TT using RFLP-PCR.

DISCUSSION AND CONCLUSION

Our findings suggest that polymorphism rs10573247 may contribute to the risk of breast cancer through the functional effect of this polymorphism on miRNA binding.

HMGA2 regulation by miRNAs in cancer: affecting cancer hallmarks and therapy response

High mobility group A 2 (HMGA2) is a protein that modulates the structure of chromatin in the nucleus. Importantly, aberrant expression of HMGA2 occurs during carcinogenesis, and this protein is an upstream mediator of cancer hallmarks including evasion of apoptosis, proliferation, invasion, metastasis, and therapy resistance. HMGA2 targets critical signaling pathways such as Wnt/β-catenin and mTOR in cancer cells. Therefore, suppression of HMGA2 function notably decreases cancer progression and improves outcome in patients. As HMGA2 is mainly oncogenic, targeting expression by non-coding RNAs (ncRNAs) is crucial to take into consideration since it affects HMGA2 function. MicroRNAs (miRNAs) belong to ncRNAs and are master regulators of vital cell processes, which affect all aspects of cancer hallmarks. Long ncRNAs (lncRNAs) and circular RNAs (circRNAs), other members of ncRNAs, are upstream mediators of miRNAs. The current review intends to discuss the importance of the miRNA/HMGA2 axis in modulation of various types of cancer, and mentions lncRNAs and circRNAs, which regulate this axis as upstream mediators. Finally, we discuss the effect of miRNAs and HMGA2 interactions on the response of cancer cells to therapy. Regarding the critical role of HMGA2 in regulation of critical signaling pathways in cancer cells, and considering the confirmed interaction between HMGA2 and one of the master regulators of cancer, miRNAs, targeting miRNA/HMGA2 axis in cancer therapy is promising and this could be the subject of future clinical trial experiments.

HMGA2 rs968697 T > C polymorphism is associated with the risk of colorectal cancer

A genetic polymorphism (rs968697 T > C) in the HMGA2 gene has recently been linked to an increased risk of hepatoblastoma. However, no studies have been conducted to investigate the effect of the polymorphism on the risk of colorectal cancer (CRC). The study aimed to explore whether the rs968697 polymorphism had a significant impact on CRC risk. A total of 500 CRC patients and 500 age and gender matched healthy individuals were genotyped by using the SNaPshot method. Quantitative real-time PCR technology was used to detect the relative expression of the HMGA2 gene in 30 pairs of primary CRC and adjacent non-cancerous tissues. Results: HMGA2 rs968697 polymorphism was significantly associated with CRC risk [CC vs. TT: OR = 0.20, 95%CI = 0.06-0.70, P = 0.01; (CC + CT) vs. TT: OR = 0.71, 95%CI = 0.53-0.96, P = 0.02; CC vs. (CT + TT): OR = 0.21, 95%CI = 0.06-0.73, P = 0.01; C vs. T: OR = 0.67, 95%CI = 0.51-0.89, P < 0.01]. The analysis based on tumor stage indicated that the CRC patients with HMGA2 rs968697 C allele were less likely to have high-stage tumors. Furthermore, the genotype-tissue expression analysis revealed that the rs968697 CC genotype was linked to the low expression of HMGA2 gene. The in silico analysis revealed that the rs968697 polymorphism in the promoter region of the HMGA2 gene could influence transcription factor binding, including ATF6, DBP, CDPCR3, DR3, NRSF, PAX8, PPARA, SZF11, TAXCREB and POLR2A. In conclusion, our findings suggested that the HMGA2 rs968697 polymorphism was linked to CRC risk and could be used as a biomarker to detect CRC risk.