Ginsenoside Rh2-induced inhibition of histone deacetylase 6 promotes K562 cells autophagy and apoptosis in vivo

Abstract

To study the in vivo inhibition effect of ginsenoside Rh₂ on humanleukemia cells, and explore its mechanism from autophagy and apoptosis aspects, human leukemia K562 cells allograft tumor models were applied, and after administration of ginsenosides Rh₂ by gavage, the tumor diameter, volume and inhibitory rate were measured, and the anti-tumor activity of ginsenosides Rh₂ was observed. The levels of HAT and HDAC in tumor tissues were detected by chemical colorimetry assay, and expressions of HDAC1, HDAC2, HDAC3, HDAC4, HDAC5 and HDAC6 were detected by Western blotting assay. The expression levels of vital genes closely associated with autophagy and mRNA expressions of HDAC6 and Hsp90 were detected by Real time-PCR. HE staining was used to observe apoptosis, and immunohistochemistry was used to detect the protein expressions of HDAC6, Hsp90 and activated caspases 3. The results showed that ginsenoside Rh₂ could inhibit the growth of k562 cells allograft tumor, with a tumor inhibition rate up to 53.10%. Ginsenoside Rh₂ could significantly decrease HDAC activity and decrease the expressions of HDAC1, HDAC2 and HDAC6, and inhibit the expressions of HDAC6 and HSP90, increase the expressions of vital autophagy genes (beclin-1, LC3A and LC3B). Histopathological results showed that ginsenosides Rh₂ could significantly increase the tumor apoptosis. Therefore, ginsenoside Rh₂ had good anti-tumor effect in vivo, and the mechanism maybe associated with regulating autophagy and apoptosis through HDAC6 and Hsp90 pathways and inhibiting the in vivo proliferation of tumor cells.