title: Cholesterol and phytosterols differentially regulate the expression of caveolin 1 and a downstream prostate cell growth-suppressor gene.
abstract: BACKGROUND
  The purpose of our study was to show the distinction between the apoptotic and anti-proliferative signaling of phytosterols and cholesterol-enrichment in prostate cancer cell lines, mediated by the differential transcription of caveolin-1, and N-myc downstream-regulated gene 1 (NDRG1), a pro-apoptotic androgen-regulated tumor suppressor.
  
  
  METHODS
  PC-3 and DU145 cells were treated with sterols (cholesterol and phytosterols) for 72h, followed by trypan blue dye-exclusion measurement of necrosis and cell growth measured with a Coulter counter. Sterol induction of cell growth-suppressor gene expression was evaluated by mRNA transcription using RT-PCR, while cell cycle analysis was performed by FACS analysis. Altered expression of Ndrg1 protein was confirmed by Western blot analysis. Apoptosis was evaluated by real time RT-PCR amplification of P53, Bcl-2 gene and its related pro- and anti-apoptotic family members.
  
  
  RESULTS
  Physiological doses (16microM) of cholesterol and phytosterols were not cytotoxic in these cells. Cholesterol-enrichment promoted cell growth (P<0.05), while phytosterols significantly induced growth-suppression (P<0.05) and apoptosis. Cell cycle analysis showed that contrary to cholesterol, phytosterols decreased mitotic subpopulations. We demonstrated for the first time that cholesterols concertedly attenuated the expression of caveolin-1 (cav-1) and NDRG1 genes in both prostate cancer cell lines. Phytosterols had the opposite effect by inducing overexpression of cav-1, a known mediator of androgen-dependent signals that presumably control cell growth or apoptosis.
  
  
  CONCLUSIONS
  Cholesterol and phytosterol treatment differentially regulated the growth of prostate cancer cells and the expression of p53 and cav-1, a gene that regulates androgen-regulated signals. These sterols also differentially regulated cell cycle arrest, downstream pro-apoptotic androgen-regulated tumor suppressor, NDRG1 suggesting that cav-1 may mediate pro-apoptotic NDRG1 signals. Elucidation of the mechanism for sterol modulation of growth and apoptosis signaling may reveal potential targets for cancer prevention and/or chemotherapeutic intervention. Sterol regulation of NDRG1 transcription suggests its potential as biomarker for prediction of neoplasms that would be responsive to chemoprevention by phytosterols.
authors.affiliation: Department of Biological Sciences, Clark Atlanta University, Atlanta, GA 30314, USA. gifere@cau.edu
authors.forename: Godwin O
authors.initials: GO
authors.lastname: Ifere
authors.forename: Anita
authors.initials: A
authors.lastname: Equan
authors.forename: Kereen
authors.initials: K
authors.lastname: Gordon
authors.forename: Peri
authors.initials: P
authors.lastname: Nagappan
authors.forename: Joseph U
authors.initials: JU
authors.lastname: Igietseme
authors.forename: Godwin A
authors.initials: GA
authors.lastname: Ananaba
mesh_terms: D017209:Apoptosis / Q000187:drug effects; D015153:Blotting, Western; D051242:Caveolin 1 / Q000235:genetics* / Q000378:metabolism; D018797:Cell Cycle Proteins / Q000235:genetics* / Q000378:metabolism; D049109:Cell Proliferation / Q000187:drug effects; D002784:Cholesterol / Q000494:pharmacology*; D005434:Flow Cytometry; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects*; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics* / Q000378:metabolism; D008297:Male; D010840:Phytosterols / Q000494:pharmacology*; D011471:Prostatic Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D012333:RNA, Messenger / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014407:Tumor Cells, Cultured; D000099259:N-myc Downstream-Regulated Gene 1 Protein
chemical_list: D051242:Caveolin 1; D018797:Cell Cycle Proteins; D002784:Cholesterol; D047908:Intracellular Signaling Peptides and Proteins; D010840:Phytosterols; D012333:RNA, Messenger; D000099259:N-myc Downstream-Regulated Gene 1 Protein; C495540:CAV1 protein, human
references.citation: J Nutr Biochem. 2003 Feb;14(2):111-9
references.pmid: 12667603
references.citation: Acta Biochim Pol. 2004;51(4):1059-65
references.pmid: 15625578
references.citation: Mol Pharmacol. 2009 Nov;76(5):1082-93
references.pmid: 19696145
references.citation: Am J Physiol Cell Physiol. 2005 Mar;288(3):C494-506
references.pmid: 15692148
references.citation: J Cell Biochem. 2004 Jan 1;91(1):54-69
references.pmid: 14689582
references.citation: Physiol Rev. 2004 Oct;84(4):1341-79
references.pmid: 15383654
references.citation: J Cell Mol Med. 2006 Apr-Jun;10(2):529-44
references.pmid: 16796818
references.citation: Biotechnol Bioeng. 2006 Mar 5;93(4):820-7
references.pmid: 16189819
references.citation: J Biol Chem. 2003 Oct 10;278(41):39527-33
references.pmid: 12890678
references.citation: Leuk Res. 1988;12(10):823-31
references.pmid: 3199842
references.citation: Oncogene. 2004 Jan 15;23(2):605-11
references.pmid: 14724589
references.citation: Cancer Gene Ther. 2004 Mar;11(3):208-14
references.pmid: 14671673
references.citation: J Lipid Res. 2003 Sep;44(9):1622-32
references.pmid: 12777465
references.citation: J Steroid Biochem Mol Biol. 2004 Nov;92(4):273-9
references.pmid: 15663990
references.citation: Ann Med. 2004;36(8):584-95
references.pmid: 15768830
references.citation: Front Biosci. 2006 May 01;11:1388-413
references.pmid: 16368524
references.citation: J Biol Chem. 1994 Dec 9;269(49):30761-4
references.pmid: 7983002
references.citation: Biophys J. 2003 Dec;85(6):3788-801
references.pmid: 14645069
references.citation: J Biol Chem. 2000 Jun 9;275(23):17221-4
references.pmid: 10770957
references.citation: Nat Med. 1998 Sep;4(9):1062-4
references.pmid: 9734401
references.citation: J Pediatr Hematol Oncol. 1999 Jan-Feb;21(1):19-25
references.pmid: 10029807
references.citation: Am J Physiol Heart Circ Physiol. 2006 Aug;291(2):H677-86
references.pmid: 16603689
references.citation: J Nutr. 2000 Sep;130(9):2127-30
references.pmid: 10958802
references.citation: Cancer Detect Prev. 2009;32(4):319-28
references.pmid: 19186008
references.citation: Oncogene. 2002 Apr 4;21(15):2365-75
references.pmid: 11948420
references.citation: Nutr Cancer. 2000;36(2):238-41
references.pmid: 10890036
references.citation: Histochem Cell Biol. 2002 Nov;118(5):399-408
references.pmid: 12432451
references.citation: Clin Cancer Res. 2004 Jan 1;10(1 Pt 1):222-7
references.pmid: 14734473
references.citation: Mol Cell Biol. 2003 Mar;23(5):1633-46
references.pmid: 12588983
references.citation: J Biol Chem. 1996 Nov 15;271(46):29182-90
references.pmid: 8910575
references.citation: Appl Environ Microbiol. 1993 Feb;59(2):547-51
references.pmid: 8434920
references.citation: Clin Cancer Res. 2000 Sep;6(9):3430-3
references.pmid: 10999725
references.citation: Cancer Cell Int. 2007 Mar 02;7:1
references.pmid: 17331262
references.citation: Curr Urol Rep. 2006 May;7(3):181-5
references.pmid: 16630521
references.citation: Eur J Cancer Prev. 2001 Dec;10(6):507-13
references.pmid: 11916349
references.citation: Mol Biol Cell. 2001 Aug;12(8):2229-44
references.pmid: 11514613
references.citation: Biophys J. 2005 Oct;89(4):2443-57
references.pmid: 16040758
references.citation: Mol Biol Cell. 1999 Nov;10(11):3607-22
references.pmid: 10564259
references.citation: J Biol Chem. 2004 Nov 19;279(47):48930-40
references.pmid: 15377670
references.citation: FASEB J. 2005 Feb;19(2):237-9
references.pmid: 15545301
references.citation: J Biol Chem. 2001 Apr 20;276(16):13442-51
references.pmid: 11278309
references.citation: Cancer Res. 1999 Nov 15;59(22):5719-23
references.pmid: 10582690
references.citation: Dis Esophagus. 2006;19(6):454-8
references.pmid: 17069588
references.citation: Mol Biol Cell. 2002 Jul;13(7):2502-17
references.pmid: 12134086
references.citation: J Nutr. 2000 May;130(5):1166-78
references.pmid: 10801914
references.citation: Biochemistry. 2000 Feb 29;39(8):1966-72
references.pmid: 10684646
references.citation: J Lipid Res. 1997 Feb;38(2):348-60
references.pmid: 9162754
references.citation: Carcinogenesis. 2004 Jun;25(6):1011-4
references.pmid: 14764460
references.citation: Am J Physiol Cell Physiol. 2009 Oct;297(4):C935-44
references.pmid: 19625610
references.citation: Gene. 2008 Jul 1;417(1-2):5-12
references.pmid: 18455888
references.citation: Mol Cell Biol. 2003 Dec;23(24):9389-404
references.pmid: 14645548
references.citation: Cancer Res. 2001 Jun 1;61(11):4386-92
references.pmid: 11389065
references.citation: Harefuah. 2006 Jan;145(1):47-51, 76-7
references.pmid: 16450727
references.citation: BMC Genet. 2004 Sep 02;5:27
references.pmid: 15341671
references.citation: Nutr Cancer. 1998;32(1):8-12
references.pmid: 9824850
references.citation: Toxicol In Vitro. 1994 Feb;8(1):47-54
references.pmid: 20692888
references.citation: Circulation. 2003 May 6;107(17):2270-3
references.pmid: 12732593
references.citation: Mol Cell Biol. 2004 May;24(9):3949-56
references.pmid: 15082788
references.citation: J Clin Invest. 2005 Apr;115(4):959-68
references.pmid: 15776112