title: CCAAT/enhancer-binding protein delta: a molecular target of 1,25-dihydroxyvitamin D3 in androgen-responsive prostate cancer LNCaP cells.
abstract: 1,25-Dihydroxyvitamin D3 [1,25(OH)2D3], the active metabolite of vitamin D3, inhibits the proliferation of prostate cancer cells. However, the molecular mechanisms by which 1,25(OH)2D3 inhibits the proliferation of these cells remain to be fully elucidated. In this study, we used microarray technology to identify target genes of 1,25(OH)2D3 in androgen-responsive prostate cancer LNCaP cells. 1,25(OH)2D3 up-regulated CCAAT/enhancer-binding protein delta (C/EBPdelta) by approximately 5-fold in these cells. Knockdown of C/EBPdelta expression by RNA interference showed that C/EBPdelta is essential for the significant growth inhibition of LNCaP cells in response to 1,25(OH)2D3 treatment. Moreover, we found that 1,25(OH)2D3 induced C/EBPdelta in other cancer cells, including the estrogen receptor (ER)-expressing MCF-7 and T47D breast cancer cells that are sensitive to the growth inhibitory effects of 1,25(OH)2D3. On the other hand, 1,25(OH)2D3 was not able to induce C/EBPdelta in either androgen receptor-negative PC-3 and DU145 or ER-negative breast cancer MDA-MB-231 cells that were relatively resistant to growth inhibition by 1,25(OH)2D3. Furthermore, forced expression of C/EBPdelta in prostate cancer LNCaP as well as breast cancer MCF-7 and T47D cells dramatically reduced their clonal growth. Taken together, forced expression of C/EBPdelta in cancer cells may be a promising therapeutic strategy.
authors.affiliation: Division of Hematology/Oncology, Cedars-Sinai Medical Center, University of California at Los Angeles School of Medicine, Los Angeles, California, USA. ikezoet@med.kochi-ms.ac.jp
authors.forename: Takayuki
authors.initials: T
authors.lastname: Ikezoe
authors.forename: Sigal
authors.initials: S
authors.lastname: Gery
authors.forename: Dong
authors.initials: D
authors.lastname: Yin
authors.forename: James
authors.initials: J
authors.lastname: O'Kelly
authors.forename: Lise
authors.initials: L
authors.lastname: Binderup
authors.forename: Nathan
authors.initials: N
authors.lastname: Lemp
authors.forename: Hirokuni
authors.initials: H
authors.lastname: Taguchi
authors.forename: H Phillip
authors.initials: HP
authors.lastname: Koeffler
mesh_terms: D000728:Androgens / Q000502:physiology; D001943:Breast Neoplasms / Q000188:drug therapy / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D051743:CCAAT-Enhancer-Binding Protein-delta; D022762:CCAAT-Enhancer-Binding Proteins / Q000037:antagonists & inhibitors / Q000096:biosynthesis* / Q000235:genetics; D002117:Calcitriol / Q000494:pharmacology*; D048708:Cell Growth Processes / Q000187:drug effects / Q000502:physiology; D045744:Cell Line, Tumor; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006801:Humans; D008297:Male; D009376:Neoplasms, Hormone-Dependent / Q000188:drug therapy* / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D020411:Oligonucleotide Array Sequence Analysis; D011471:Prostatic Neoplasms / Q000188:drug therapy* / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D011944:Receptors, Androgen / Q000096:biosynthesis; D011960:Receptors, Estrogen / Q000096:biosynthesis; D014157:Transcription Factors / Q000037:antagonists & inhibitors / Q000096:biosynthesis* / Q000235:genetics; D015854:Up-Regulation / Q000187:drug effects
chemical_list: D000728:Androgens; D022762:CCAAT-Enhancer-Binding Proteins; C497252:CEBPD protein, human; D011944:Receptors, Androgen; D011960:Receptors, Estrogen; D014157:Transcription Factors; D051743:CCAAT-Enhancer-Binding Protein-delta; D002117:Calcitriol