Hsa_circ_0000038 Inhibits the Progression of Hepatocellular Carcinoma by Sponging miR-92a-2-5p to Regulate the p53/p21 Pathway

Abstract

Background: The diagnostic potential of circular RNAs (circRNAs) has garnered significant attention recently. However, the specific mechanisms by which various circRNAs operate in different cancers, particularly hepatocellular carcinoma (HCC), require further investigation.

Methods: Quantitative real-time fluorescence polymerase chain reaction (RT-qPCR) was utilized to evaluate the expression levels of hsa_circ_0000038. Western blotting was employed to assess the protein expression levels of p53, p21, and p27. To comprehensively understand the functional implications of hsa_circ_0000038, a series of cellular assays were performed, including cell clonal formation experiment, the CP6 system for cell proliferation and Transwell assays for evaluating invasion and migration. Additionally, luciferase and co-immunoprecipitation assays were conducted to explore the interactions between miR-92a-2-5p and hsa_circ_0000038 or Tp53.

Results: Our findings demonstrated that hsa_circ_0000038 was significantly downregulated in both HCC tissues and cell lines. Overexpression of hsa_circ_0000038 was shown to arrest the cell cycle of HepG2 cells (p53 wild-type) at the G0–G1 phase, thereby repressing cell proliferation, invasion, and migration in vitro. In contrast, hsa_circ_0000038 overexpression had minimal effects on the cell cycle in Hep3B cells (p53-deficient). Co-transfection with miR-92a-2-5p partially mitigated the effects of hsa_circ_0000038 in HepG2 cells. Further analysis revealed that hsa_circ_0000038 directly binds to miR-92a-2-5p and that Tp53 mRNA is a direct target of miR-92a-2-5p. Through regulatory network analysis, hsa_circ_0000038 was shown to upregulate the expression of p53, p21, and p27 proteins.

Conclusion: This study highlights the downregulated expression of hsa_circ_0000038 HCC and identifies it as a crucial regulator of the miR-92a-2-5p/p53/p21 axis. These findings suggest that hsa_circ_0000038 may play a significant role in inhibiting HCC progression through cell cycle arrest. Furthermore, this research enhances our understanding of the complex molecular mechanisms underlying hepatocarcinoma pathogenesis.