title: Increased sensitivity of Hep G2 cells toward the cytotoxicity of cisplatin by the treatment of piper betel leaf extract.
abstract: Piper betel leaves (PBL) are used in Chinese folk medicine for the treatment of various disorders. PBL has the biological capabilities of de-toxication, anti-oxidation and anti-mutation. In this study we first examined the effect of PBL extract on the activity of Glutathione S-transferase (GST) isoforms, and found that it inhibited total GST and the alpha class of GST (GSTA), but not the pi class of GST (GSTP), and the mu class of GST (GSTM), activity in Hep G2 cells. RT-PCR results verified a reduction in the expression of GSTA1. Next, we examined whether PBL extract could increase the sensitivity of Hep G2 cells to anti-cancer drugs. The data showed that the cytotoxicity of cisplatin was significantly enhanced by the presence of PBL extract, accompanied by a reduction in the expression of multidrug resistance protein 2 (MRP2). These effects of PBL extract were compared to its major constitute, eugenol. Although eugenol decreased MRP2 level more effectively than PBL extract, it exhibited less sensitizing effect. In conclusion, we demonstrated that PBL extract was able to increase the sensitivity of Hep G2 cells to cisplatin via at least two mechanisms, reducing the expression of MRP2 and inhibiting the activity of total GST and the expression of GSTA. The data of this study support an application of PBL as an additive to reduce drug resistance.
authors.affiliation: Institute of Biochemistry and Biotechnology, Chung Shan Medical University, No 110, section 2, Chien Kauo N. Road, 402, Taichung, Taiwan.
authors.forename: Shun-Chieh
authors.initials: SC
authors.lastname: Young
authors.forename: Chau-Jong
authors.initials: CJ
authors.lastname: Wang
authors.forename: Jeng-Dong
authors.initials: JD
authors.lastname: Hsu
authors.forename: Jui-Ling
authors.initials: JL
authors.lastname: Hsu
authors.forename: Fen-Pi
authors.initials: FP
authors.lastname: Chou
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology*; D002458:Cell Fractionation; D045744:Cell Line, Tumor / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D002945:Cisplatin / Q000494:pharmacology*; D004365:Drugs, Chinese Herbal; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D005054:Eugenol / Q000494:pharmacology; D016195:G2 Phase; D005982:Glutathione Transferase / Q000378:metabolism; D022781:Hepatocytes / Q000187:drug effects* / Q000201:enzymology / Q000473:pathology; D006801:Humans; D007527:Isoenzymes; D008113:Liver Neoplasms / Q000188:drug therapy; D026901:Membrane Transport Proteins / Q000378:metabolism; D000089762:Multidrug Resistance-Associated Protein 2; D027425:ATP-Binding Cassette, Sub-Family C Proteins / Q000378:metabolism; D009944:Organoplatinum Compounds / Q000494:pharmacology; D000077150:Oxaliplatin; D031721:Piper betle; D010936:Plant Extracts / Q000494:pharmacology*; D018515:Plant Leaves / Q000737:chemistry
chemical_list: D000970:Antineoplastic Agents; D002945:Cisplatin; D004365:Drugs, Chinese Herbal; D004791:Enzyme Inhibitors; D005054:Eugenol; D005982:Glutathione Transferase; D007527:Isoenzymes; D026901:Membrane Transport Proteins; D000089762:Multidrug Resistance-Associated Protein 2; D027425:ATP-Binding Cassette, Sub-Family C Proteins; D009944:Organoplatinum Compounds; D000077150:Oxaliplatin; D010936:Plant Extracts; C000715087:ABCC2 protein, human