title: Ginkgo biloba extract EGb 761-mediated inhibition of aromatase for the treatment of hormone-dependent breast cancer.
abstract: Ginkgo biloba has been used in herbal medicines for thousands of years. Although a standard G. biloba extract, EGb 761 has been used to improve cognition in breast cancer patients, its effects on breast cancer are unknown. Therefore, we investigated the antitumorigenic effects of EGb 761 using an in vitro cell model and an in vivo xenograft model. EGb 761 significantly inhibited aromatase activity in aromatase over-expressing MCF-7 cells (MCF-7 AROM). In addition, EGb 761 exposure reduced cytochrome p450 aromatase (CYP19) mRNA and protein expression; CYP19 promoter I.3 and PII expression particularly decreased. These inhibitory effects on aromatase were accompanied by reduced 17β-estradiol levels in MCF-7 AROM cells. For elucidating antitumorigenic effects, MCF-7 AROM cells were implanted in BALB/c nude mice prior to oral EGb 761 treatment for 3 weeks. EGb 761 reduced the tumor size and significantly reduced tumor CYP19 mRNA expression. Taken together, our results indicated that EGb 761 inhibited aromatase and exerted antitumor effects on breast cancer cells both in vitro and in vivo. These findings suggest that EGb761 may be a useful aromatase inhibitor for the treatment for estrogen-sensitive breast cancer.
authors.affiliation: School of Pharmacy, Sungkyunkwan University, 300, Suwon, Gyeonggi-do, 440-746, Republic of Korea.
authors.forename: Yong Joo
authors.initials: YJ
authors.lastname: Park
authors.affiliation: Department of Nanofusion Technology, Hoseo University, Asan, Chungnam, 31499, Republic of Korea.
authors.forename: Hui Yeon
authors.initials: HY
authors.lastname: Ahn
authors.affiliation: School of Pharmacy, Sungkyunkwan University, 300, Suwon, Gyeonggi-do, 440-746, Republic of Korea.
authors.forename: Ha Ryong
authors.initials: HR
authors.lastname: Kim
authors.affiliation: School of Pharmacy, Sungkyunkwan University, 300, Suwon, Gyeonggi-do, 440-746, Republic of Korea. Electronic address: khchung@skku.edu.
authors.forename: Kyu Hyuck
authors.initials: KH
authors.lastname: Chung
authors.affiliation: Department of Nanofusion Technology, Hoseo University, Asan, Chungnam, 31499, Republic of Korea. Electronic address: ohsm0403@hoseo.edu.
authors.forename: Seung Min
authors.initials: SM
authors.lastname: Oh
mesh_terms: D000077384:Anastrozole; D000818:Animals; D018931:Antineoplastic Agents, Hormonal / Q000494:pharmacology; D000972:Antineoplastic Agents, Phytogenic / Q000008:administration & dosage / Q000494:pharmacology; D001141:Aromatase / Q000235:genetics / Q000378:metabolism*; D001943:Breast Neoplasms; D049109:Cell Proliferation; D004305:Dose-Response Relationship, Drug; D005260:Female; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects*; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects*; D020441:Ginkgo biloba; D006801:Humans; D061986:MCF-7 Cells; D015674:Mammary Neoplasms, Animal / Q000188:drug therapy*; D051379:Mice; D009374:Neoplasms, Experimental / Q000188:drug therapy; D009570:Nitriles / Q000494:pharmacology; D010936:Plant Extracts / Q000008:administration & dosage / Q000494:pharmacology*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D014230:Triazoles / Q000494:pharmacology; D000096983:Ginkgo Extract
chemical_list: D000077384:Anastrozole; D018931:Antineoplastic Agents, Hormonal; D000972:Antineoplastic Agents, Phytogenic; D001141:Aromatase; D009570:Nitriles; D010936:Plant Extracts; D012333:RNA, Messenger; D014230:Triazoles; C063170:Ginkgo biloba extract; D000096983:Ginkgo Extract; C561410:CYP19A1 protein, human
keywords: 17β-estradiol biosynthesis; Aromatase inhibitor; Aromatase promoters; Breast cancer; EGb 761; Xenograft