MicroRNA-155 is highly expressed in lung cancer, breast cancer, acute myelogenous leukemia (AML), Hodgkin’s disease, pediatric Burkitt’s lymphoma, pancreatic tumour and chronic lymphocytic leukaemia (CLL) (33). MicroRNA-155 has an essential function in regulating T helper cell differentiation and the germinal centre reaction to produce an optimal T cell dependent antibody response, at least in part, by regulating cytokine production (34). MicroRNA-155 also participates in other cellular processes such as interferon production in natural killer cells, lymphoma cell motility, dendritic cell differentiation and function and skeletal muscle differentiation etc. (35, 36)
MicroRNA-17 – 92 is intensified and overexpressed in hematopoietic malignancies (37). Myc induces the expression of this microRNA cluster and the mature microRNAs expressed repress E2F transcription factors in a complex network and controls cell cycle progression and apoptosis (38). These microRNAs can modulate the expression of many different molecules involved in several cellular processes including apoptosis, tumour suppression, cell cycle and cytokine signalling (39).
MicroRNA-21 is overexpressed in most tumour types including brain, colon, lung, breast, pancreatic, cervical and oesophageal cancers. Inhibition of microRNA-21 results in growth inhibition and up regulation of the cell cycle inhibitor P 21 (40). P 21 is a cyclin dependent kinase inhibitor that regulates the cell cycle. Meng et al. showed that inhibition of microRNA-21 in liver cancer cells decreased tumour cell migration, proliferation and cell invasion (41).
Secondly we’ll look at Diabetes – another silent killer,
MicroRNA and Diabetes
Over 2.2 million people with diabetes have been recognized in the UK by the Diabetic Retinopathy Screening Programme in 2013. The incidence of Type II diabetes is increasing in every country especially in developing countries such as India and China (42). This is mainly due to immobility and obesity (42). By 2030, the world incidence of diabetes is expected to reach 366 million (42, 43). Diabetes is a common lifelong health condition.
In Type I diabetes, pancreatic beta cells do not produce insulin and in Type II, cells do not recognise the peptide hormone, insulin (104). The...