title: Involvement of protein tyrosine phosphorylation and reduction of cellular sulfhydryl groups in cell death induced by 1' -acetoxychavicol acetate in Ehrlich ascites tumor cells.
abstract: Elucidation of the mechanisms underlying potential anticancer drugs continues and unraveling these mechanisms would not only provide a conceptual framework for drug design but also promote use of natural products for chemotherapy. To further evaluate the efficacy of the anticancer activity of 1'-acetoxychavicol acetate (ACA), this study investigates the underlying mechanisms by which ACA induces death of Ehrlich ascites tumor cells. ACA treatment induced loss of cell viability, and Western blotting analysis revealed that the compound stimulated tyrosine phosphorylation of several proteins with 27 and 70 kDa proteins being regulated in both dose- and time-dependent manner prior to loss of viability. Protein tyrosine kinase inhibitor herbimycin A moderately protected cells from ACA-induced toxicity. In addition, cellular glutathione and protein sulfydryl groups were also significantly reduced both dose- and time-dependently during evidence of cell death. Replenishing thiol levels by antioxidant, N-acetylcysteine (NAC), an excellent supplier of glutathione and precursor of glutathione, substantially recovered the viability loss, but the recovery being time-dependent, as late addition of NAC (at least 30 min after ACA addition to cultures) was, however, ineffective. Addition of NAC to ACA treated cultures also abolished tyrosine phosphorylation of the 27 kDa protein. These results, at least partly, identify cellular sulfhydryl groups and protein tyrosine phosphorylation as targets of ACA cytotoxicity in tumor cells.
authors.affiliation: Department of Food and Human Health Sciences, Graduate School of Human Life Science, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585, Japan.
authors.forename: Jerry
authors.initials: J
authors.lastname: Moffatt
authors.forename: David Opare
authors.initials: DO
authors.lastname: Kennedy
authors.forename: Akiko
authors.initials: A
authors.lastname: Kojima
authors.forename: Tadayoshi
authors.initials: T
authors.lastname: Hasuma
authors.forename: Yoshihisa
authors.initials: Y
authors.lastname: Yano
authors.forename: Shuzo
authors.initials: S
authors.lastname: Otani
authors.forename: Akira
authors.initials: A
authors.lastname: Murakami
authors.forename: Koichi
authors.initials: K
authors.lastname: Koshimizu
authors.forename: Hajime
authors.initials: H
authors.lastname: Ohigashi
authors.forename: Isao
authors.initials: I
authors.lastname: Matsui-Yuasa
mesh_terms: D000818:Animals; D016588:Anticarcinogenic Agents / Q000494:pharmacology*; D016227:Benzoquinones; D001592:Benzyl Alcohols; D015153:Blotting, Western; D002286:Carcinoma, Ehrlich Tumor / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D002470:Cell Survival / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005978:Glutathione / Q000378:metabolism; D047029:Lactams, Macrocyclic; D010084:Oxidation-Reduction; D010766:Phosphorylation; D011809:Quinones / Q000494:pharmacology; D017828:Rifabutin / Q000031:analogs & derivatives; D013438:Sulfhydryl Compounds / Q000378:metabolism; D013729:Terpenes / Q000494:pharmacology*; D013997:Time Factors; D014407:Tumor Cells, Cultured / Q000187:drug effects; D014443:Tyrosine / Q000378:metabolism*
chemical_list: D016588:Anticarcinogenic Agents; D016227:Benzoquinones; D001592:Benzyl Alcohols; D004791:Enzyme Inhibitors; D047029:Lactams, Macrocyclic; D011809:Quinones; D013438:Sulfhydryl Compounds; D013729:Terpenes; D017828:Rifabutin; D014443:Tyrosine; C020754:herbimycin; D005978:Glutathione; C047948:1'-acetoxychavicol acetate