Anti-Colorectal Cancer Effect And Mechanism Of Ginsenoside Rh4

During the last two decades,the use of ginsenosides in cancer therapy has been attracted much attention and intensively investigated.The main active components of the Panax genus(Ginseng,Panax notoginseng,American Ginseng)are ginsenosides.The ginsenoside Rh4 is a main rare ginsenoside of steamed and heat-processed Panax ginseng,Panax notoginseng and American ginseng extracts.Ginsenoside Rh4 is characterized by the ability to dissolve more readily in water than other polysaccharide-ginsenosides,facilitating its utilization in pharmaceutics.However,because of the difficulty associated with its extraction,little attention has been paid to the effect of ginsenoside Rh4,especially for colorectal carcinoma.Here,we investigated the antiproliferative activity and the underlying mechanisms of Rh4 in colorectal cancer,both in vivo and in vitro.In vitro study,we investigated the antiproliferative effect of ginsenoside Rh4 on colorectal cancer cell Caco-2 and HCT116 and normal colon epithelial cells CCD-18 Co by CCK-8assays,and the effects of ginsenoside Rh4 on the colony formation of Caco-2,HCT116 and CCD-18 Co.In vivo study,a colorectal cancer xenograft model was established and after intraperitoneal injection of ginsenoside Rh4,the body weights and tumor sizes of the mice were measured,and the liver,kidneys,lungs and heart were studied by histological analysis.Our present study indicated that ginsenoside Rh4 could significantly inhibit colorectal cancer and exhibit low toxicity,and few side effects in vivo and in vitro.Futhermore,ginsenoside Rh4 could inhibit the colony formation of Caco-2 and HCT116,but was not significantly inhibition to CCD-18 Co.We investigated the effect of ginsenoside Rh4 on cell cycle arrest,apoptosis and autophagy in Caco-2 and HCT116 by flow cytometric analysis,Hoechst 33342 staining,Transmission electron microscope(TEM)analysis,Annexin V/PI staining,Western blotting and immunohistochemistry.Results revealed that ginsenoside Rh4 could induce G0/G1 phase arrest,caspase-dependent apoptosis and autophagic cell death.Furthermore,apoptosis played a dominant role in Rh4-induced cell death,as the pan-caspase inhibitor Z-VAD-FMK blocked cell death to a greater extent than the autophagy inhibitor3-methyladenine.We investigated the effect of ginsenoside Rh4 on reactive oxygen species(ROS)and MAPK-p53 pathway by DCFH-DA staining,Western blotting and immunohistochemistry.Results revealed that ginsenoside Rh4 increased ROS accumulation and subsequently activated the JNK-p53 pathway.Moreover,an ROS scavenger and JNK and p53 inhibitors significantly attenuated ginsenoside Rh4-induced apoptosis and autophagy.Thus,the present study is the first to illustrate that Rh4 triggers apoptosis and autophagy via activating the ROS/JNK/p53 pathway in colorectal cancer cells,providing basic scientific evidence that ginsenoside Rh4 shows great potential as an anti-cancer agent.