The Significant Role of miRNAs in Lung Cancer

Lung cancer is the first death- leading cause of cancer in the world. Since lung cancer is diagnosed at advanced stages and has one of the lowest 5-year survival rate (~15%), the identification of biomarkers for early diagnosis and accurate prognosis of lung cancer is a promising strategy in early detection of lung cancer. microRNAs which are a small non-coding RNAs regulate mRNA and protein expression and might be a candidate biomarker. For example in a cohortstudy it has been demonstrated that miR-21 and miR-210 which are mostly up-regulated might be an appropriate biomarkerin lung cancer. Furthermore, some of the defects are occurred during miRNAs biogenesis process while others are the different expression level of miRNAs in tumor samples versus normal tissues. Drosha, DGCR8 and Dicer are the enzymes which are involved in miRNAs biogenesis process. Deletion of Dicer abrogates the production of mature miRNA. Also, its deletion enhances lung tumor development in a K-Ras-induced lung cancer mouse model. miRNAs can act as tumorsuppressor genes or oncogenes. Let-7 acts as a tumor suppressor gene and in humans, the let-7 family which locateson different chromosomal regions that are frequently deleted in lung cancer. miR-17-92 cluster and miR-31acts as oncogenes that corporation with c-Myc accelerate tumor development. The overexpression of miR- 17-92 cluster in small cell lung cancer is correlated with Rb inactivation. Thereby, this cluster may be a suitable therapeutic target in lung cancer. Furthermore, miRNAs can be the key cause of chemotherapeutic failure. Finally, miRNAs might be used for targeted therapy in lung cancer.

کلیدواژه ها:

Lung Cancer ، micoRNA ، Biomarkers ، tumor suppressor ، Oncogenes