Circular RNA expression and circPTPRM promotes proliferation and migration in hepatocellular carcinoma

Circular RNAs (circRNAs) play a critical role during hepatocellular carcinoma (HCC) development. CircRNA PTPRM (circPTPRM) has not been reported to cause disease and its role in HCC is unclear. This study explored circRNA expression and the function of circPTPRM in HCC. RNA sequencing (RNA-seq) was performed on 3 randomly selected pairs of HCC tissues and their corresponding adjacent non-tumor tissues. Three differentially expressed circRNAs, circPTPRM, circSMAD2 and circPTBP3 were selected and verified by real-time quantitative reverse transcription-polymerase chain reactions in 30 pairs of tissue samples, In vitro cultured hepatoma cells, and normal liver cells. Clinical data analysis was performed to select target circRNAs. Anti-target circRNA siRNAs were transfected into hepatoma cell lines, and the biological behavior of hepatoma cells following silencing of the target circRNA were detected by cell proliferation, plate cloning, and transwell assays. There were 86 differentially expressed circRNAs from RNA-seq, of which 53 were significantly upregulated and 33 were significantly downregulated in HCC. CircPTPRM expression was significantly upregulated in HCC tissue (p = 0.023) based on the analysis of 30 paired samples. CircPTPRM expression positively correlated with HCC recurrence and metastasis (p = 0.039). CircPTPRM silencing reduced HCC cell proliferation, migration and invasion. CircRNAs were differentially expressed in HCC samples. CircPTPRM was significantly upregulated in HCC and may function during the tumorigenesis and metastasis of HCC.