The role of lncRNAs in Hepatocellular carcinoma

Introduction: Hepatocellular carcinoma (HCC) is one of the most common and aggressive human malignancies. The dismal clinical outcome of HCC is largely due to the high incidence of intrahepatic and extrahepatic metastasis in HCC patients. Long non-coding RNAs (lncRNAs) are a group of non-protein-coding RNAs that are greater than 200 nucleotides in length. They serve as either oncogenes or tumor suppressor genes and play a vital role in tumorigenesis.Description: Several different lncRNAs, including HULC, HOTAIR, MALAT1 and H19 were identified that are deregulated during HCC tumorigenesis and metastasis. HULC with 1.6 k nucleotide long contains two exons but not translated. Its upregulation deregulates lipid metabolism and promotes metastasis in HCC. Furthermore, HULC inhibits apoptosis mediated by miR-9. HOTAIR has been reported to be an oncogene that influences tumor cell development and correlates with prognosis in HCC by repressing RBM38. MALAT1 promotes the migration and invasion of HCC by mediating of miR-204 and miR-200a pathways. MALAT1 knockdown inhibits the proliferation, migration, and invasion, and induces apoptosis in hypoxia-challenged Hepatocells. These results indicate that MALAT1 plays an important role in tumor progression and could be a novel biomarker for predicting tumor prognosis. The H19 gene encodes a 2.3 k nucleotide lncRNA that is exclusively expressed from the maternal allele. H19 downregulates in HCC is correlated with its decreased promotor methylation.Discussion and conclusion: Abnormal expression of lncRNA might interrupt gene expression in genetic and epigenetic level and was associated with prognosis of hepatocellular. LncRNAs that are found in body fluids could detected by next generation technologies. This implied the possibility of lncRNA to become a diagnosis biomarker and therapeutic target of HCC.