Anti-hepatocellular carcinoma activity of Sorbaria sorbifolia by regulating VEGFR and c-Met/apoptotic pathway

Sorbaria sorbifolia (SS) is a traditional Chinese medicine (TCM) that has been employed anti-hepatocellular carcinoma (HCC) for over 2000 years; yet, its underlying mechanism is still not fully understood. In this study, we evaluated the anti-HCC effect on the freeze-dried powder of the water extract of SS (FDSS) by inhibiting tumor-induced neovascularization, and promoting apoptosis, and elucidated the underlying mechanisms. HCC cell lines (HepG2 and Huh7 cells) and HepG2 xenograft tumors in zebrafish were employed as in vivo and in vitro models, respectively, to evaluate the anti- HCC-indued neovascularization and apoptosis. In HCC cell lines, CCK-8 assay, wound-healing assay, transwell assay, cell circle assay, apoptosis assay, transmission electron microscopy, and co-culture assay were performed in vitro; in HepG2 xenograft tumor-zebrafish, tumor growth inhibition assay, hematoxylin and eosin (HE) staining, xenograft tumor-zebrafish apoptosis assay, and HCC-indued neovascularization assay were performed to evaluate the effect of FDSS on biological behavior of tumor, HCC-indued neovascularization, and apoptosis. The expression of VEGFR and c-Met/apoptotic pathway-related proteins was detected by western blotting analysis. Assays for c-Met and VEGFR activation were conducted to assess the impact of FDSS in either agonistic or inhibitory roles on these receptor proteins. The findings from our study revealed that FDSS effectively suppresses the proliferation, migration, and invasion of HepG2 and Huh7 cells, as well as inhibiting tumor growth in the HepG2 xenograft zebrafish model by downregulating the expression of p-Met and p-AKT proteins. FDSS decreased the tumor growth associated with promoting apoptosis, including arresting HepG2 and Huh7 cells cycle at G0/G1phase, increasing apoptotic cell numbers and apoptotic bodies in cancer cells, and increasing the apoptotic fluorescence of xenograft tumor zebrafish by downregulating Bcl-2 proteins and upregulating Bax, caspase-9, and caspase-3 levels. We also found that FDSS can inhibit HCC-induced neovascularization and regulate VEGFR. Using an agonist or inhibitor of c-Met and VEGFR in HepG2 cells, we discovered that FDSS can downregulate c-Met and VEGFR protein expression. FDSS exerts an anti-HCC effect by inhibiting HCC-indued neovascularization and pro-apoptosis through the inhibition of the action of VEGFR and c-Met/apoptotic pathway.