microRNA expression

Neoplastic development represents cumulative genetic and epigenetic events leading to the emergence of cells that can attain a tumorigenic phenotype. Neoplastic transformation of cells cultured in vitro can be induced by several methods, such as treatment with chemical carcinogens or radiation, viral infection, or the introduction of oncogenes. To help understand how tumors originate and progress in mammals, cells transformed in vitro by these methods have been used for many years to study processes analogous to neoplastic development in vivo.

To identify miRNA signatures associated with different stages of neoplastic development, the authors used custom microarrays containing primate miRNAs to examine the expression profile in VERO cells (a neoplastically transformed cell line being used for the manufacture of viral vaccines), progenitor primary African green monkey kidney (pAGMK) cells, and several VERO cell derivatives. Because the genome sequence of the African green monkey is not available, there are no commercially available miRNA arrays specific to the African green monkey. Therefore, a custom primate miRNA microarray that contained all human and non-human primate miRNA transcripts (776 miRs from 11 species, miRBase V10) was used. [click to continue…]

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Researchers at East Carolina University and report for the first time the microRNA expression profile of human breast cancer MCF-7 cells and the effect of green tea.  microRNA Microarray identified twenty three miRNAs that exhibit differential expression after a 48 h treatment with 10 μg/ml Polyphenon-60 (green tea extract).

These miRNAs include miR-21 and miR-27 that were found to be down-regulated following treatment with green tea. These two miRNAs have previously been identified as being overexpressed in MCF-7 breast cancer cells, with miR-21 specifically implicated in down-regulating the tumor suppressor gene, tropomyosin-1.

This data supports the hypothesis that Polyphenon-60-induced modification of the breast cancer miRNA expression profile contributes to the efficacy of green tea treatment. The resulting decrease in carcinogenesis is further supported by the altered miRNA regulation of potential oncogenes and tumor-suppressor genes.

Fix N, Shah M, Efferth T, Farwell M, Zhang B. (2010) MicroRNA Expression Profile of MCF-7 Human Breast Cancer Cells and the Effect of Green Tea Polyphenon-60. Cancer Genomics & Proteomics 7(5), 261-277. [abstract]

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untitledSteatohepatitis is a type of liver disease, characterized by inflammation and fat accumulation in the liver, which can lead to cirrhosis. Steatohepatitis is frequently seen in alcoholics and people with diabetes and/or obesity and alcoholic and nonalcoholic steatohepatitis are leading causes of liver diseases worldwide. Researchers at UMASS Medical School used microarray to examine the microRNA expression profiles in mouse models of steatohepatitis of both alcoholic and non-alcoholic etiology1. The data they present about the baseline status of the microRNA profile in normal liver and upon development of steatohepatitis facilitate better understanding of this disease and opens new avenues for research its pathophysiology. 

  1. Dolganiuc A, Petrasek J, Kodys K, Catalano D, Mandrekar P, Velayudham A, Szabo G. (2009) MicroRNA Expression Profile in Lieber-DeCarli Diet-Induced Alcoholic and Methionine Choline Deficient Diet-Induced Nonalcoholic Steatohepatitis Models in MiceAlcohol Clin Exp Res  33(10), 1704-10.  [abstract]

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