MicroRNA-26a inhibits proliferation by targeting high mobility group AT-hook 1 in breast cancer.

OBJECTIVES: To investigate the crucial role of miR-26a in breast cancer and to validate whether miR-26a could regulate proliferation of breast cancer cells by targeting high mobility group AT-hook 1 (HMGA1). METHODS: Reverse transcription-polymerase chain reaction (RT-PCR) was used to quantify the expression levels of miR-26a in breast cancer and adjacent non-cancerous breast tissues. MTT, cell migration and invasion assay were carried out to characterize the miR-26a function. Finally, to validate the target gene of miR-26a, luciferase reporter assay was employed, followed by RT-PCR and Western blot confirmation. RESULTS: Compared with normal tissues, a significant down-regulation of miR-26a expression was observed in breast cancer tissues (P=0.002). miR-26a suppresses MDA-MB-231 and Mcf-7 breast cancer cell lines proliferation and motility. The luciferase activity was significantly decreased after co-transfection with psiCHECK-2/HMGA1 3'-UTR and miR-26a mimics in comparison with control cells, and qRT-PCR and Western blotting analysis found that HMGA1 expression at the mRNA and protein levels decreased in the miR-26a mimic-treatment group relative to NC. MTT assay showed that down regulation of HMGA1 by siRNA could significantly enhance the tumor-suppressive effect of miR-26a (P < 0.05). CONCLUSIONS: The results of the present study indicate that miR-26a may be associated with human breast carcinogenesis, which inhibits tumor cell proliferation by targeting HMGA1.

Genetic variations of CAV1 gene contribute to HCC risk: a case-control study.

Hepatocellular carcinoma (HCC) is the sixth common cancer and the third common cause of cancer mortality worldwide. However, the exact molecular mechanism of HCC remains uncertain. Caveolin-1 (CAV1) is the main protein in the caveolin family and plays an important role in tumorigenesis signaling. However, the contribution of CAV1 genetic variants to HCC is still unknown. The purpose of this study was to evaluate the association between the tagSNPs of the CAV1 gene and HCC risk. In this case-control study, we enrolled 1,000 HCC patients and 1,000 cancer-free controls, which were frequency-matched by age, gender, and HBV infection status. We found that CAV1 rs729949 was statistically associated with increased risk of HCC (odds ratio (OR) = 1.28; 95% confidence interval (CI), 1.11-1.48; P = 8.53 × 10(-4)), even after Bonferroni correction (P = 5.97 × 10(-3)); the expression levels of CAV1 in cancer tissues were significantly lower than those in adjacent normal tissues (P = 0.012). We also detected a significant association for CAV1 rs3807989 under the log-additive model (OR = 0.85; 95% CI, 0.74-0.98; P = 0.026). Significant associations were also detected for CAV1 rs6466583 (GG vs AA: OR = 2.53; 95% CI, 1.24-5.17; P = 0.011) and CAV1 rs3807986 (AG vs AA: OR = 3.16; 95% CI, 1.68-5.91; P = 3.36 × 10(-4)) among genotype comparisons. These findings indicated that genetic variants n CAV1 might contribute to HCC susceptibility.