title: Inhibition of P-glycoprotein by wogonin is involved with the potentiation of etoposide-induced apoptosis in cancer cells.
abstract: Etoposide induces apoptotic cell death in normal and cancer cells. This apoptosis plays a role not only in anticancer effects but also in adverse reactions, such as myelosuppression. Because we had previously found that wogonin, a flavone found in a plant, suppresses thymocyte apoptosis induced by etoposide, we examined the effect of this flavone in cancer cells. Wogonin significantly potentiated etoposide-induced apoptosis in HL-60 cells. This flavone impaired the function of P-glycoprotein and then increased cellular content of etoposide in the cells. Thus, this flavone is likely to act as an inhibitor of P-glycoprotein and potentiate the apoptotic action of etoposide. On the other hand, wogonin inhibited etoposide-induced apoptosis in thymocytes, one of the normal cells. The potentiation by wogonin is likely to be a specific action for cancer cells but not normal cells. Therefore, this flavone may be used to reduce the excretion of the anticancer agents via P-glycoprotein and increase the pharmacological action of it in cancer cells. These results suggest that wogonin may play a role in overcoming multidrug resistance.
authors.affiliation: Department of Pharmacology, Kobe Gakuin University, Kobe, Japan. elee@pharm.kobegakuin.ac.jp
authors.forename: Eibai
authors.initials: E
authors.lastname: Lee
authors.forename: Riyo
authors.initials: R
authors.lastname: Enomoto
authors.forename: Chika
authors.initials: C
authors.lastname: Koshiba
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Hirano
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000037:antagonists & inhibitors* / Q000378:metabolism; D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D004357:Drug Synergism; D004365:Drugs, Chinese Herbal / Q000494:pharmacology; D005047:Etoposide / Q000494:pharmacology*; D044950:Flavanones / Q000494:pharmacology*; D005434:Flow Cytometry; D018922:HL-60 Cells; D006801:Humans; D020287:In Situ Nick-End Labeling; D015473:Leukemia, Promyelocytic, Acute / Q000378:metabolism / Q000473:pathology
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D000972:Antineoplastic Agents, Phytogenic; D004365:Drugs, Chinese Herbal; D044950:Flavanones; D005047:Etoposide; C085514:wogonin