Effect Of PHLDA2 On The Function Of Colon Cancer And Hepatocellular Carcinoma And Its Mechanism

PART1 EFFECT OF PHLDA2 ON THE FUNCTION OF COLON CANCER AND ITS MECHANISMObjective: Colorectal cancer(CRC)has the highest incidence and mortality rates in all gastrointestinal tumor types.However,novel effective treatment strategies for CRC are still lacking.PHLDA2(Pleckstrin homology like domain family a member 2)as an imprinted gene to promote or suppress tumor progression in breast cancer,pancreatic ductal adenocarcinoma,and osteosarcoma.In the present study,we aim to explore the role and underlying mechanisms of PHLDA2 on colon cancer in vivo and in vitro.Methods: The mRNA expression levels of PHLDA2 in colon cancer,adjacent normal tissues and cells were detected by qRT-PCR.The protenin expression levels of PHLDA2 in colon cancer,adjacent normal tissues and cells were detected by IHC and western blot.The effects of different knockdown fragments on PHLDA2 expression level were detected by qRT-PCR,and appropriate fragments and lentiviral vectors were selectedfor splicing,packaged into lentivirus,and then transfected into HCT16 and SW480 cell lines.The proliferation ability of HCT116 and SW480 cells in vitro was detected by CCK-8 and colony formation assays.Transwell invasion and migration assay to detect the invasion and migration ability of HCT116 and SW480 cells in vitro.Flow cytometry to detect cell cycle and apoptosis level.Transmission electron microscopy(TEM)to detect autophagy level.Western blot to detect related protein expression level.Furthermore,the effect of PHLDA2 on cell proliferation in nude mice was assessed by xenograft model and KI67 staining.Results: PHLDA2 expression was upregulated in colon cancer tissues.Knockdown of PHLDA2 inhibited cell proliferation,invasion,migration and EMT but promoted cells apoptosis by activating autophagy in vitro.Furthermore,knockdown of PHLDA2 inhibited Tumorigenesis in vivo.The regulatory effects of PHLDA2 to autophagy and EMT were done partially through the PI3K-AKT signaling pathway.Conclusions: We confirm that PHLDA2 as a tumor promoter.PHLDA2 down-regulation can inhibit tumor growth and restrained the activity of PI3 K to promote autophagy and inhibit EMT in part through the PI3K/AKT/mTOR and PI3K/AKT/GSK-3β signaling pathways in colon cancer.PART2 EFFECT OF PHLDA2 ON PROLIFERATION,MIGRATION,INVASION AND APOPTOSIS IN HEPATOCELLULAR CARCINOMA CELLSObjective: To observe the expression of Pleckstrin homology like domain family a member 2(PHLDA2)in hepatocellular carcinoma(HCC)and investigate the effect of PHLDA2 on cell proliferation,migration,invasion and apoptosis.Methods: To analyze the expression of PHLDA2 in HCC tissues and adjacent normal tissues and the effect of PHLDA2 expression on overall survival rate of HCC patients by Gene Expression Profiling Interactive Analysis(GEPIA)Online database.Screening stable transfected cell lines.The cell proliferation of Hep3 B and Huh7 cells were determined by CCK-8and Colony formation assay.The invasion and apoptosis of Hep3 B and Huh7 cells were detected by transwell assay.The percentage of apoptosis of Hep3 B and Huh7 cells were measured by flow cytometry.Results: The expression of PHLDA2 is upregulated in HCC,and high expression of PHLDA2 reduced the overall survival of HCC patients.Low-expression of PHLDA2 inhibit proliferation,invasion and migration,and increase apoptosis of Hep3 B and Huh7 cells.Conclusion: PHLDA2 promote the occurrence and development and may act as tumor promoter in HCC.