Dehydrocostus lactone inhibits the proliferation and metastasis of hepatocellular carcinoma cells via modulating p53-p21-CDK2 signaling pathway

Hepatocellular carcinoma (HCC), a malignancy with high mortality and recurrence rates, has very limited options for treatment strategies. Dehydrocostus lactone (DL) is the principal quality marker extracted from Aucklandia lappa Decne. and has been demonstrated to possess excellent anticancer activity. The key purpose of this study was to explore the therapeutic effects and potential mechanisms of DL on HCC. The effect of DL on the cell viability of HCC cell lines (HepG2 and SK-HEP-1) and normal human hepatocyte cell line (L-O2) was examined by CCK8, colony formation, and BeyoClickTMEdU-488 assays; Hoechst 33,258 staining and flow cytometry were utilized to determine the impact of DL on apoptosis; the sensitivity of HCC cells to DL was explored by adding Z-VAD-fmk. In addition, the expression of apoptosis-related proteins Bax, Bcl-2, and PARP was detected by western blotting; the expression of p-H2AX was investigated by western blotting and immunofluorescence staining; cell cycle distribution was observed using flow cytometry; the migration ability and invasiveness of HCC cells were assessed by wound healing assay and transwell assay; immunoblotting was applied to visualize the levels of EMT markers in the two HCC cell lines. Transcriptome sequencing was performed to reveal the underlying mechanisms of DL anti-tumor; western blotting and qRT-PCR were employed to verify the mRNA and protein abundance of p53, p21, and CDK2; HepG2 xenograft in mice was used to test the anti-tumor effects of DL in vivo. DL suppressed the proliferation of HCC cell lines (HepG2 and SK-HEP-1) but had little effect on a normal human liver cell line (L-O2). In addition, DL also induced apoptotic death of the HCC cells by activating Bax and downregulating Bcl-2. The antiproliferative effects of DL could be attributed to increased DNA damage and G1-phase cell cycle arrest. Moreover, DL inhibited HCC cell invasiveness and migration in vitro by decreasing the levels of β-catenin, N-cadherin, and TCF8/ZEB1, and increasing the E-cadherin level. RNA sequencing indicated that DL exerted its anti-hepatoma effects partly via regulation of p53-p21-CDK2 signaling. These results were validated by our in vivo experiments, in which DL markedly suppressed the growth of HepG2 xenografts in a mouse model without any toxic side effects, which corresponded to decreased expression of Ki67 and MMP9 in the tumor tissues. DL has significant anti-cancer effects in both in vivo and in vitro HCC models, and therefore could be further developed as a promising drug for the treatment of HCC.