astragaloside-ii and Carcinoma--Hepatocellular

Inhibition of autophagy has been increasingly recognized as a potential therapeutic approach against cancer. Our previous reports showed that Astragaloside II improves hepatic cancer cells resistance by downregulating MDR1 and P-gp .The purpose of this study was to further investigated the effect of autophagy on AS-II reversing multidrug resistance and its molecular mechanism in hepatocellular carcinoma cells in vitro.. Bel-7402 and Bel-7402/FU cell lines were used in this study. Western blot was used to detect the expression of autophagy-related protein, p-mTOR and p-p79s6k, MTT was used to analyse cell viability, GFP-LC3 punctate dots distribution was observed by GFP-LC3 transient transfection under fluorescence microscopy and silencing of autophagy-related genes was detected by small interfering RNA transfection.. Astragaloside II was able to significantly decrease the expression of LC3-II and Beclin-1 in a dose-dependent manner, Astragaloside II (80 μm) further decreased LC3-II formation, Beclin-1 and GFP-LC3 puncta dots stimulated with 5-fluorouracil (0.2 mm) in Bel-7402/FU cells (P < 0.05). In addition, Astragaloside II is capable of sensitizing cells to 5-fluorouracil-induced cell death via inhibition of pro-survival autophagy involvement of MAPK-mTOR pathway.. These findings suggested that Astragaloside II could suppress autophagy by interfering with Beclin-1 and LC3 via MAPK-mTOR pathway, through which sensitized human cancer resistant cells to 5-FU-induced cell death.

Topics: Apoptosis; Apoptosis Regulatory Proteins; Autophagy; Beclin-1; Carcinoma, Hepatocellular; Cell Line, Tumor; Cell Survival; Drug Resistance, Multiple; Fluorouracil; Humans; Liver Neoplasms; Mitogen-Activated Protein Kinases; RNA Interference; RNA, Small Interfering; Saponins; Signal Transduction; TOR Serine-Threonine Kinases

Chemoresistance is the main obstacle encountered in cancer treatment and is frequently associated with multidrug resistance (MDR). Astragaloside is a saponin which is widely used in traditional Chinese medicine. It has been reported that Astragaloside has antitumour effects on hepatocellular carcinoma Bel-7402 cells in vitro and in vivo. The purpose of this study was to examine the effects of Astragaloside II on the reversal of MDR and its molecular mechanism in vitro.. In this study, Bel-7402 and Bel-7402/FU cell lines were used as the experimental model. Drug sensitivity was determined using the 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay, accumulation and efflux of Rh123 were analyzed by flow cytometer, the mRNA level of mdr1 was determined by RT-PCR and the protein levels of P-glycoprotein (P-gp) and mitogen-activated protein kinase were determined by Western blot.. Astragaloside II (0.08 mg/ml) showed strong potency to increase 5-fluorouracil cytotoxicity toward 5-fluorouracil-resistant human hepatic cancer cells Bel-7402/FU. The mechanism of Astragaloside II on P-gp-mediated MDR demonstrated that Astragaloside II significantly increased the intracellular accumulation of rhodamine 123 via inhibition of P-gp transport function. Based on the analysis of P-gp and mdr1 gene expression using Western blot and RT-PCR, the results revealed that Astragaloside II could downregulate the expression of the P-gp and mdr1 gene. In addition, Astragaloside II suppressed phosphorylation of extracellular signal regulated kinase 1/2, p38 and c-Jun N-terminal kinase.. The results suggested that Astragaloside II is a potent MDR reversal agent and may be a potential adjunctive agent for hepatic cancer chemotherapy.

Topics: Antimetabolites, Antineoplastic; Antineoplastic Agents, Phytogenic; Astragalus Plant; ATP Binding Cassette Transporter, Subfamily B; ATP Binding Cassette Transporter, Subfamily B, Member 1; Biological Transport; Carcinoma, Hepatocellular; Cell Line, Tumor; Down-Regulation; Drug Resistance, Multiple; Fluorouracil; Gene Expression; Humans; Liver Neoplasms; Mitogen-Activated Protein Kinases; Phosphorylation; Phytotherapy; Plant Extracts; Rhodamine 123; Saponins