MicroRNAs (miRNAs), a class of small noncoding RNA molecules, can manipulate the expressions of endogenous tumor-related genes, and are implicated in the development and progression of a wide type of tumors. In this study, the investigation from real-time quantitative PCR revealed that miRNA-16-5p was downregulated in breast carcinoma tissues and cells, coupled with the elevations of HIF-α and VEGFA protein expressions, compared with normal tissues. Lentiviral armed with miR-16-5p markedly increased the miR-16-5p levels in MCF-7 and MDA-MB-231 cells, compared to blank and NC groups, and miR-16-5p overexpression significantly inhibited the proliferation and colony formation in MCF-7 and MDA-MB-231 cells. Besides, miR-16-5p upregulation markedly induced apoptosis and reduced invasion ability in MCF-7 and MDA-MB-231 cells. Notably, VEGFA was direct target of miR-16-5p. Stepwise investigation from in vitro and in vivo experiments demonstrated that miR-16-5p overexpression suppressed tumor growth and reduced HIF-α and VEGFA expressions in breast carcinoma cells and nude mice tumor tissues. These findings provide novel insights into molecular mechanism involved in the roles of miR-16-5p in tumor development and progression of breast carcinoma, and thus manipulation of miR-16-5p may be a novel potential therapeutic target for future therapies of the patients with breast carcinoma.
Abstract.It is well documented that B cell-specific Moloney murine leukemia virus integration site 1 (Bmi-1), widely overexpressed in the vast majority of malignancies, plays an essential role in the occurrence and development of several different tumors. Here, we report Bmi-1 siRNA-mediated cell proliferation inhibition and cell apoptosis in vitro and in vivo in the human breast carcinoma cell line MCF-7. Our results demonstrated that Bmi-1 siRNA effectively down-regulated the expression of Bmi-1, inhibited cell proliferation in vitro and in vivo, evoked cell cycle arrest in the G 0 /G 1 phase and induced cell apoptosis in MCF-7 cells, coupled with decrease in cyclin D1, cyclin E, cdk2, bcl-2 and Ki-67 expression and Akt phosphorylation levels and an increase of p21 and bax expression and activities of caspase-3/-9. Taken together, our results suggest that Bmi-1 may be a potential molecular target for the therapy of breast carcinoma.
ABSTRACT. Breast cancer is one of the most frequently diagnosed cancer in women worldwide, and we conducted a case-control study by genotyping seven potentially functional SNPs, three in ERCC1 and four in XPF, in a Chinese population of 417 breast cancer cases and 417 cancer-free controls. Three SNPs in ERCC1 and four SNPs in XPF were genotyped by using the Taqman Universal PCR Master Mix in the GeneAmp ® PCR System 9700 with Dual 384-Well Sample Block Module, and assays were performed on a 384-well plate on the Sequenom MassARRAY platform. We found that elevated breast cancer risk was associated with those who had a family history of breast cancer and history of breast disease, and those who were over 25 years old at first full-term pregnancy. We found that decreased risk of breast cancer was associated with those who had a history of fullterm pregnancies. Compared with the ERCC1 rs11615 T/T genotype, a significantly higher risk of breast cancer was found in the C/C genotype in codominant and dominant models after adjusting for potential risk factors. Similarly, we found that ERCC1 rs3212986 C/C genotype was associated with an increased risk of breast cancer in codominant, dominant and recessive models. Our study indicated that the ERCC1 rs11615 and rs2298881 polymorphisms are associated with breast cancer in a Chinese population. Further studies with large sample size are greatly needed to elucidate the SNPs of ERCC1 and XPF genes in the development of breast cancer.
The growth and metastasis of tumors is dependent on angiogenesis; however, the association between tumor stem cells (TSCs) and tumor angiogenesis remains to be elucidated. The present study aimed to investigate the expression of the TSC markers aldehyde dehydrogenase 1 (ALDH1) and cluster of differentiation 133 (CD133) in invasive ductal breast carcinoma, and identify their correlation with tumor angiogenesis. Stem-like cells from the breast tissue of 120 patients, who were diagnosed with invasive ductal breast carcinoma at The First Affiliated Hospital of Zhengzhou University (Zhengzhou, Henan, China) between January 2009 and December 2010, were collected by surgical resection and analyzed using immunohistochemical double staining. The expression of the vascular markers CD34, CD105 and vascular endothelial growth factor (VEGF) were determined using single staining. Overall, 25.83% (31/120) of the specimens contained a large number of ALDH1+/CD133+ stem-like cells (ALDH1+/CD133+ tumor). ALDH1+/CD133+ expression is associated with microvessel density, VEGF-positive rate and estrogen receptor expression (P<0.05); however, ALDH1+/CD133+ expression was not associated with age, tumor diameter, lymph node metastasis, histological classification, progesterone receptor expression or human epidermal growth factor receptor 2 expression (P>0.05). The ALDH1+/CD133+ tumor phenotype and expression of VEGF were identified to be correlated in the present study (P=0.020). The present study revealed a close association between breast cancer TSC markers, including ALDH1 and CD133, and tumor angiogenesis. The results of the present study may provide a novel target and treatment strategy for future studies investigating tumor growth and metastasis.
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