Document Type : Research Articles
The Second Affiliated Hospital of Chongqing Medical University, Chongqing, P.R. China.
Laboratory of Stem Cell and Tissue Engineering, Department of Histology and Embryology, Chongqing Medical University, Chongqing, China.
Department of Pharmacy, Renhe Community Health Service Center of Chongqing Liangjiang New Area, Chongqing, China.
The First People’s Hospital of Chongqing Liangjiang New Area, Chongqing, China.
Chongqing Three Gorges Medical College, Chongqing, P.R. China.
Purpose: To investigate the effect of 20(S)-ginsenoside Rh2 (Rh2) on anti HepG2 liver cancer cells and HepG2 cell-derived xenograft tumors, and explore the underlying mechanisms. Materials and Methods: The activity of total HDACs and HAT were assessed with a HDACs colorimetric kit. Expression of HDAC1, HDAC2, HDAC6, p-ERK, ERK, p-P38, P38, p-JNK and JNK proteins was tested by Western blotting.H3K9 and H3K14 proteins were also checked by immunofluorescence, changes in cell cycle distribution with flow cytometry, cell apoptosis with annexin V-FTIC/PI double staining. Activity of Renilla luciferase (HIF) was detected using the Luciferase Reporter Assay system reagent. Gene expression for CyclinD1, Bcl-2, Bax, HIF, IL-1, IL-6, IL-10 and TNF-α was tested by q-PCR. Expression levels of CD31 and Ki-67 was tested by immunohistochemical staining. Results: Total HDAC activity was decreased and total histone acetyltransferase (HAT)activity was increased in a time-dependent manner. Expression of HDAC1 and p-JNK proteins was significantly increased, expression levels of p-ERK was decreased. H3K9 and H3K14 fluorescence protein were increased. Flow cytometric analysis of the cell cycle revealed that the percentage of cells in the G0/G1 phase in the treatment group(64.35±1.36%) was significantly increased compared with the untreated group(61.61±1.23%).The apoptotic rate of the HepG2 group was 10.03±1.92%, which increased to 17.87±1.67% in the treatment group. Expression levels of the transcription factor HIF were also increased in HepG2 cells following induction by Rh2. Expression of CyclinD1 and Bcl-2 at the genetic level was significantly decreased, while expression levels of Bax, HIF, IL-1, IL-6, IL-10 and TNF-α was increased. In vivo, the expression levels of both CD31 and Ki-67 proteins were significantly down-regulated in the treatment group compared with the control group. Conclusions: The effects of Rh2 were suggested to occur through the inhibition of total HDAC activity, which subsequently induced MAPK signaling and down-regulated the expression of HIF.