title: Androgenic suppression of ATP-binding cassette transporter A1 expression in LNCaP human prostate cancer cells.
abstract: Alteration of lipid metabolism is commonly observed in sex hormone-dependent cancer cells, yet its mechanistic involvement in cancer cell proliferation and progression is unclear. We have found that the expression of the cholesterol transporter, ATP-binding cassette transporter A1 (ABCA1), was 15- to 20-fold higher in androgen-dependent than in androgen-independent LNCaP human prostate cancer cells, indicating a possible relationship between the expression levels of ABCA1 and prostate cancer progression. On the basis of real-time quantitative PCR and Western blot analysis, expression of ABCA1 in androgen-dependent cells was inhibited by androgen. The antiandrogen Casodex blocked the effect of androgen, implicating the androgen receptor in regulation of ABCA1 expression by androgens. Using an ABCA1 promoter-reporter gene assay, androgenic suppression was observed at the transcriptional level in androgen-dependent but not in androgen-independent prostate cancer cells. ABCA1 appears to have a role in modulating cell proliferation because knockdown of ABCA1 expression by RNA interference in androgen-dependent cells increased their rate of proliferation. Therefore, a suppressive effect of androgen on ABCA1 expression may be one of the mechanisms by which androgens regulate proliferation in prostate cancer cells. Attenuated ABCA1 expression in androgen-independent cells thus may contribute, in part, to prostate cancer progression.
authors.affiliation: Ben May Institute for Cancer Research and Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, Illinois 60637, USA.
authors.forename: Junichi
authors.initials: J
authors.lastname: Fukuchi
authors.forename: Richard A
authors.initials: RA
authors.lastname: Hiipakka
authors.forename: John M
authors.initials: JM
authors.lastname: Kokontis
authors.forename: Stephen
authors.initials: S
authors.lastname: Hsu
authors.forename: Andrew L
authors.initials: AL
authors.lastname: Ko
authors.forename: Michael L
authors.initials: ML
authors.lastname: Fitzgerald
authors.forename: Shutsung
authors.initials: S
authors.lastname: Liao
mesh_terms: D064286:ATP Binding Cassette Transporter 1; D018528:ATP-Binding Cassette Transporters / Q000235:genetics*; D000728:Androgens / Q000494:pharmacology*; D001483:Base Sequence; D045744:Cell Line, Tumor; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects*; D006801:Humans; D008297:Male; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D011471:Prostatic Neoplasms / Q000378:metabolism*; D012333:RNA, Messenger / Q000032:analysis
chemical_list: C577836:ABCA1 protein, human; D064286:ATP Binding Cassette Transporter 1; D018528:ATP-Binding Cassette Transporters; D000728:Androgens; D012333:RNA, Messenger