Deciphering the effects of PYCR1 on cell function and its associated mechanism in hepatocellular carcinoma

Although over-expression of Pyrroline-5-carboxylate reductase 1 (PYCR1) has been reported to be associated with development of certain cancers, no studies have specifically examined the impact of PYCR1 on hepatocellular carcinoma (HCC). From The Cancer Genome Atlas (TCGA) expression array and meta-analysis conducted using Gene Expression Omnibus（GEO）, and verified via real-time quantitative RT-PCR (qRT-PCR), western blot, and immunohistochemistry analysis, we determined that PYCR1 was up-regulated in HCC compared to normal tissues (P < 0.05). Additionally, patients with low PYCR1 expression showed a higher overall survival rate; while PYCR1 over-expression was associated with females, higher levels of alpha fetoprotein, higher clinical stages (stages III and IV) and younger (< 45 years old) patients. Silencing PYCR1 inhibited cell proliferation, invasive migration, epithelial-mesenchymal transition (EMT)and metastatic properties in vitro and in vivo. Using RNA sequencing (RNA-seq) and bioinformatics tools for data-dependent network analysis, we further found binary relationships among PYCR1 and its interactors in defined pathway modules, implicating PYCR1 in a multi-functional role of coordinating a variety of biological pathways involved incell communication, cell proliferation-growth, cell migration, MAPK cascade, ion-binging, etc. The protein structure characters of key pathway components or PYCR1 interactors evaluated by molecular docking and hot spot analysis showed that the better infinities between PYCR1 and its interactors contained “arginine” in all binding site sequences. Finally, a potential regulatory microRNA (miRNA)-miR-2355-5p of PYCR1 mRNA was discovered in HCC. Overall, our study suggests that PYCR1 plays a vital role in HCC pathogenesis and may serve as a potential molecular target for HCC treatment. The differetial gene expression profiles of silence of PYCR1 and control in HCC cell