MicroRNAs Important Molecules in Cancer Research- Andrew Presgraves

Besides housekeeping genes, the expression of all other genes is mostly regulated through a complex mechanism that enables a cell type specific and time specific expression. Regulations can occur during each step of gene expression, e.g., during chromatin remodeling, transcription and translation, RNA transport, or on the post-transcriptional level. The main gene expression regulators are proteins or enzymes, e.g., histones, transcription factors, and polymerases. Gene expression can also be regulated by antisense or sense nucleic acids (Helene and Toulme, 1990). MicroRNAs (miRNAs) are a highly conserved family of small RNAs (17–22nt) that regulate the expression of their target genes usually on the post-transcriptional level by binding to complementary sequences on target messenger RNA transcripts (mRNAs) mostly resulting in gene silencing.(Leidinger, P)

Can we detect lung cancers earlier? Recent extensive scientific research has been conducted and currently no biomarkers exist to detect lung cancers at earlier stages. One scientific researcher has however been the first to relate miRNA expression to developments of lung caner. He found that miRNA can be found in skin tissues and this particular type is highly cell type specific and they reflect the developmental lineage and the differentiated state. MiRNAs can also be found in certain bodily fluids such as whole blood,serum, plasma, urine and cerebrospial spinal fluid, this being a much easier way to test for the miRNA. The miRNA profiles obtained from these fluid samples is very useful for the analysis and research of disease states this is especially useful when the disease does not originate from one specific cell source. How these miRNAs enter into the body fluids is still an unresolved question and is currently still being researched, but one possible explanation is cancer cells with metastatic potentials enter into the blood stream and release their cell content including miRNA material. MiRNAs packed into microvesicals or exosomes are entered into the bloodstream. In the bodily fluids test particularly saliva which contains blood cells, apoptic or detached epithelial living cells.Cell-free nucleic acids actively released by cancer and epithelial cells or inactively by apoptotic cells and micro-wounds have also been found in saliva. MicroRNAs play an essential role in lung development (Tomankova et al., 2010). Due to the different expression pattern in healthy lung tissue compared to lung cancer tissue it seemed legitimate to assume that aberrant miRNA expression may be involved in the onset of lung cancer. By microarray analyses of the miRNA expression in 104 pairs of primary lung cancers and corresponding non-cancerous lung tissues. From this a specific miRNA profile was discovered that contained more than 43 differently expresses miRNAs. This new research is definitely something that could put up a new defense towards cancers especially lung cancers which are so hard to detect in earlier stages, miRNAs have the potential to even be prognostics tools, focusing on the knowledge about miRNAs as tumor suppressor and activators for oncogenes, will lead to miRNA based therapeutic approaches.


Bibliography:

Keller, A., Leidigner, P., Meese, A. MicroRNAS Important Molecules in Lung Cancer Research. Pub Med- Frontiers in Genetics. Accessed 9 February 2012 //http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3263430/?tool=pubmed


Andrew Presgraves