Foot Track Of LncRNAs In Cancer

Only small portion of transcripts in the whole human genome are coding proteins, while moretranscripts are non-coding RANa (ncRANs). A kind of ncRNA, called long non-coding RNA (lncRNA)that are longer than 200 nucleotides, have been recently discovered. LncRNAs involved in variouscellular processes so they can involve in diverse diseases.HOX antisense intergenic RNA (HOTAIR),a lncRNA located in the HOXC locus that it is about 2158 nucleotides in size, has been shown torepress HOXD gene expression. Studies about the binding domain of HOTAIR elucidated that a 5´domain binds to PRC2 while 3´ domain binds to the LSD1/CoREST/REST complex which leading totrimethylation of H3K27 and also H3K4 demethylation respectively. EZH2 Subunit of PRC2 contentsa binding domain for HOTAIR. Furthermore, revealed that BRCA1 tumor suppressor proteininteracts with the EZH2 and Inhibits the binding of EZH2 to HOTAIR. The EZH2 is phosphorylatedduring cell cycle by CDK1 and CDK2. This Phosphorylation is essential for binding to HOTAIR. Inaddition, demonstrated that HOTAIR expression is induced by estradiol. Genome-wide analysisshowed that knock downing of HOTAIR affects the expression of genes associated with apoptosis,tumor suppression, cell differentiation, and proliferation. Induction of HOTAIR expression incancer cells cause increase invasion and metastasis.HOTAIR is overexpressed in primary breasttumors and expression level is a powerful predictor of eventual metastassis and death, in returndepletion of HOTAIR can inhibit cancer invasiveness. Also, in Hepatocellular carcinoma (HCC)increase expression of HOTAIR that associated with increased risk of recurrence after hepatectomy.Moreover, knock downing of HOTAIR in HCC as a result decrease cell proliferation and matrixmetalloproteinase-9 levels. Furthermore, HOTAIR can be used as a biomarker for HCC. Studiesabout HOTAIR expression in Colorectal cancer (CRC) indicates that it is level positive relationbetween its increasing level and CRC cells amplification and invasiveness. This reviews show thatHOTAIR has a key role in the proliferation and metastasis of cancer cells.