Quantitative assessment of the association between miR-196a2 rs11614913 polymorphism and cancer risk: evidence based on 45,816 subjects.

MicroRNAs (miRNAs) are small non-coding RNA molecules, which participate in diverse biological processes and may regulate tumor suppressor genes or oncogenes. Single nucleotide polymorphisms (SNPs) in miRNA may contribute to diverse functional consequences, including cancer development, by altering miRNA expression. Numerous studies have shown the association between miR-196a2 rs11614913 SNPs and cancer risk; however, the results are generally debatable and inconclusive, mainly due to limited statistical power. We carried out a meta-analysis of 46 studies including 20,673 cases and 25,143 controls to assess the association between the miR-196a2 rs11614913 and cancer risk by pooled odds ratios (ORs) and 95 % confidence intervals (CIs). Overall, we found a significant association between the rs11614913 (C > T) polymorphism and cancer susceptibility (recessive model, OR = 0.89, 95 % CI = 0.81-0.98). In the stratified analysis by cancer type, significant association of cancer risk was observed in lung cancer (allelic contrast, OR = 0.89, 95 % CI = 0.82-0.97; homozygote comparison, OR = 0.79, 95 % CI = 0.67-0.94; recessive model, OR = 0.84, 95 % CI = 0.74-0.96) and liver cancer (allelic contrast, OR = 0.88, 95 % CI = 0.79-0.99; homozygote comparison, OR = 0.77, 95 % CI = 0.61-0.98; heterozygote comparison, OR = 0.84, 95 % CI = 0.74-0.95; dominant model, OR = 0.82, 95 % CI = 0.73-0.92). During further stratified analysis by ethnicity, the rs11614913 polymorphism showed statistically significant association with increased risks of cancer in Asians (heterozygote model, OR = 1.15, 95 % CI = 1.01-1.30) but not in Caucasians. This meta-analysis suggests that the miR-196a2 rs11614913 polymorphism may contribute to decreased susceptibility to cancer, especially including liver cancer and lung cancer. However, it may be a risk factor for cancer development in Asians. Larger, better studies of homogeneous cancer patients are needed to further assess the correlation between this polymorphism and cancer risk.

SNCG shRNA suppressed breast cancer cell xenograft formation and growth in nude mice.

BACKGROUND: Overexpression of breast cancer-specific gene 1 (SNCG) is associated with poor prognosis in advanced breast cancer patients. This study aimed to determine the effects of SNCG knockdown in breast cancer cells by using small hairpin RNA (shRNA). METHODS: Four different SNCG shRNA oligonucleotides were designed and chemically synthesized to construct mammalian expression vectors. These vectors were then stably transfected into a breast cancer MCF-7 cell line to knockdown SNCG expression. After SNCG knockdown was confirmed, the stable cell lines were inoculated into nude mice. SNCG mRNA and protein expressions were analyzed by semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) and immunohistochemistry, respectively in both the stable cell lines and xenografts. RESULTS: All four SNCG shRNA constructs significantly reduced SNCG mRNA and protein levels in MCF-7 cells, as compared to the unrelated sequence control shRNA and the liposome control mice (P < 0.05). SNCG-knockdown MCF-7 cells formed significantly smaller tumor masses than cells expressing the unrelated sequence control or the liposome control mice (P < 0.05). CONCLUSION: SNCG shRNA effectively suppressed breast cancer cell formation in vivo and may be a useful clinical strategy to control breast cancer.