Comparing the expression of long non coding RNA “lincRNA-P21” in cancer cell lines (AGS MBA-MD468) and embryonal carcinoma cell line (NT2).

Gastric cancer is the second reason of cancer-related death in the world with particularly high prevalence in East Asia. Recently, the function of Long Non-coding RNAs (lncRNAs) as tumor suppressors or oncogene has appeared in prevalent cancer types, such as gastric cancer. LincRNA-P21 is located upstream of P21 gene and activates its expression under the control of P53 transcription factor. Thus lincRNA-P21 collaborate with the P53 tumor suppressor pathway and prevents reprogramming in somatic cell by recruiting DNA methyltransferase to the promoter region of pluripotency genes (OCT4, SOX2, NANOG,...). Altered expression of lincRNA-P21 has been reported in some cancers. In this project, we aimed to compare the expression level of lincRNA-P21 in human gastric cancer cell line (AGS), breast (MBA-MD468) cancer cell line, conjunctiva derived mesenchymal stem cells (Conj, by Dr Nadri) and also human embryonal carcinoma cell line (NT2). Cell lines were cultured in the RPMI1640 (NT2, Conj and AGS) or DMEM (MBA-MD468). Total RNA was extracted using TRIZOL reagent (Invitrogen). cDNA synthesis was performed by PrimeScript™ 1st strand cDNA Synthesis Kit (TAKARA) and real time PCR was performed by using TaqMan master mix (TAKARA) on Step one Plus™ instrument (ABI). B2M and GAPDH have been used as reference genes. Fold change of gene expression was obtained by Pfaffl formula. Despite of our expectation, NT2 embryonal carcinoma cell line showed a significant higher expression of LincRNA–P21 rather than MBA-MD468, Conj and AGS cell lines ( 5 fold change). According to our results, it seems that the expression of Lnc-RNA P21 is not silenced in embryonic carcinoma cell lines such as NT2 but it is decreased in cancer cell lines.