Lone Non-codins RNA TUG1 Regulates The Development Of Multidrug Resistance In Hepato-cellular Carcinoma Via P-gp And MDR1

Hepatocellular carcinoma(HCC)is one of the most prevalentcancers worldwide,ranking the third in malignant tumor mortality which was just next to lung cancer and gastric carcinoma.About 383,000 people die from liver cancer each year in China,which accounts for more than half of patients die from liver cancer in the world,and the high mortality has become a heavy burden to patient’s family and society.While the improvement of some treatment means such as chemotherapy,radiotherapy and surgical techniques,chemotherapy is still one of the most important ways in the comprehensive treatment for liver cancer.But the significant effect of chemotherapy in HCC is still not optimistic while the tumor multidrug resistance(MDR)is one of the main obstacles.Therefore,reversingthe mechanism underlying MDR in cancer cells is one of the most urgent problems in clinical treatment of liver cancer.Objective:It’s reported that the long non-coding RNA(IncRNA)TUG1 was significant up-regulated in various cancer tissues and the dysregulated expression of TUG1 was thought to be associated with cancer cell proliferation and metastasis.Based on the previous studies on TUG1,we presumed that it might refer to theMDRin HCC.Hence,we are aim to reveal the potential regulatory function of TUG1 in the molecular mechanisms underlying MDR inHCCby using a sets of molecular biology experiments.Methods:In this study,we identified the expression levels of TUG1 in HCC tissues of patients and two kinds of adriamycin-resistant cells SMMC-7721/ADM and HepG2/ADM by qRT-PCR,respectively.Knockdown and overexpression of TUG1 were also utilized to assess the effect on adriamycin-induced cytotoxicity and apoptosis by CCK-8 assay and flow cytometry,respectively.In addition,the protein expression level of several apoptosis related genes such as PARP and Caspase-3 were also detected in the adriamycin-resistant cells by western blotting after the knockdown or overexpression of TUG1.In the end,we investigated the expression levels of P-gp and MDR1 by western blotting and qRT-PCR,respectively.Results:The results showed that the TUG1 was up-regulated in HCC tissues and two adriamycin-resistant cells.Moreover,we found the cells of SMMC-7721/ADM and HepG2/ADM had a remarkably lower cell viability and increased apoptotic rates after transfected siTUG1.While,overexpression of TUG1 led to the opposite results in SMMC-7721 and HepG2.Furthermore,western blotting results showed that the expression level of PARP and Caspase-3 were significant down-regulated after knockdown of TUG1 and it had anopposite expression pattern when overexpressed of TUG1.At last,we found that down-regulation of TUG1 could inhibited the expression of P-gp and MDR1 while the up-regulation of TUG]could increase their expression level on the contrary.Conclusions:Taken together,these results indicated that the knockdown of TUG1 in adriamycin-resistant HCC cells can effectively reverses the adriamycin resistance and overexpression of TUG1 could inhibits adriamycin-induced apoptosis in parental HCC cells and enhance the adriamycin resistance.The main mechanism of enhance or inhibit the development of MDR in HCC might induced via regulated the expression of P-gp and MDR1.