Function And Mechanism Study Of Pseudogene PDIA3P1 In Hepatocellular Carcinoma

Hepatocellular carcinoma(HCC)is one of the most common malignant tumors of the world.In China,hepatocellular carcinoma is common and one of the leading causes of cancer-related death.Although so many efforts have been made in both scientific field and clinical field,the liver cancer-related death rate has reached second place in all cancer-related death.This tough situation is caused by the difficulties of early diagnosis of liver cancer.Most patients have missed the best chance to take tumor resection when they seek medical advice.Another reason for the high mortality of HCC is the high recurrence rate.Therefore,it's urgent to find new biomarker,explore the mechanism of tumorigenesis and develop new targeted drugs for HCC.Pseudogenes are a sub-class of non-coding RNAs,their structure are similar to their coding parent genes.However,their structure has some 'defects',which led them losing the ability to produce functional proteins.Pseudogenes are considered a no functional gene "fossil",which are generated by genetic mutations.At present,more and more studies have proved that pseudogenes can affect biological processes at DNA,RNA and protein level,more importantly,pseudogenes also participates in the process of tumorigenesis.Thus,the discovery of numerous pseudogenes,the exploration of their functions,mechanisms have provided new thoughts and directions for the early diagnosis and treatment of HCC prognosis.In this study,we investigated a novel pseudogene,PDIA3P1,and we tend to explore its role in the tumorigenesis of HCC.PART ?Expression and clinical significance of the novel pseudogene PDIA3P1 in human hepatocellular carcinomaAimsTo explore the expression of pseudogene PDIA3P1 in hepatocellular carcinoma,and the relationship between the expression level of PDIA3P1 and clinical characteristic of HCC.MethodsThe expression level of PDIA3P1 in HCC tissues and cells were detected by qRT-PCR,and the potential associations between its level in HCC tissue and clinic pathological features were analyzed.Kaplan-Meier method was used to analyze whether PDIA3P1 was associated with the overall survival rate.ResultsPDIA3P1 was significantly upregulated in five HCC cell lines(Huh7,SK-Hepl,HepG2,HCCLM3,and SMMC-7721)compared with a normal liver cell line(L02).We then detected PDIA3P1 in 90 paired HCC and adjacent normal liver tissues;fifty-one pairs showed(56%)significant upregulation of PDIA3P1 in the HCC tissues.In all 90 pairs,the expression of PDIA3P1 in tumor tissues was significantly higher than that in adjacent non-tumor tissues.PDIA3P1 expression was associated with tumor size(P=0.005),metastasis(P=0.027),and TNM stage(P=0.005;Table 1).However,there was no significant association between PDIA3P1 expression and age,HBV,AFP(hepatitis B virus,a-fetoprotein)level,tumor number,vascular invasion,or liver cirrhosis.And patients with higher PDIA3P1 expression tended to have a lower overall survival than did those with lower PDIA3P1 expressionConclusionOur data suggest that PDIA3P1 acts as an oncogene in HCC,and could be a potential diagnostic and prognostic marker for HCC.PART ?Pseudogene PDIA3P1 promotes cell proliferation,migration and invasion,and suppresses apoptosis in hepatocellular carcinomaAimsTo explore the function of pseudogene PDIA3P1 in hepatocellular carcinoma.MethodsBy transfected SMMC-7721 and HepG2 cells with non-targeting siRNA(NC)or PDIA3P1 siRNAs to explore the impact of PDIA3P1 in the biological process of HCC.We performed colony formation assay,CCK-8 assay,transwell assay to verify this impact.Than we developed a xenograft model in nude mice to confirm the tumorigenicity of PDIA3P1 in vivoResultsKnocking down of pseudogene PDIA3P1 promoted cell proliferation,migration and invasion,and suppressed apoptosis in hepatocellular carcinoma.ConclusionPDIA3P1 is a potential oncogene and promotes tumorigenesis in HCC.Part ?The underlying mechanism of PD1A3P1 in hepatocellular carcinomaAimsTo explore the mechanisms behind the role of PDIA3P1 in regulating HCC tumorigenesis.MethodsUsing FISH(fluorescence in situ hybridization)assay to confirm the subcellular localization of pseudogene PDIA3P1.Regulation of gene expression by PDIA3P1 was investigated by comparing liver cancer cells transfected with PDIA3P1 siRNA and control,and messenger RNA(mRNA)expression profiles were determined using an Affymetrix GeneChip Human Genome U133 Plus 2.0 Array.ResultsWe confirmed that PDIA3P1 localized in the nuclei of liver cancer cells mostly.p53,p21,and IGF-BP3 expression were increased after knockdown of PDIA3P1,while cyclin E1 was downregulated.ConclusionPDIA3P1 promotes proliferation and inhibits apoptosis of liver cancer cells by regulating p53 pathway.