Reduced tumor growth in vivo and increased c-Abl activity in PC3 prostate cancer cells overexpressing the Shb adapter protein.
BACKGROUND
Induction of apoptosis is one strategy for treatment of prostate cancer. The Shb adapter protein has been found to regulate apoptosis in various cell types and consequently human prostate cancer 3 (PC3) cells were transfected to obtain cells overexpressing Shb in order to increase our understanding of the mechanisms regulating PC3 cell apoptosis.


METHODS
Human prostate cancer cells (PC3) were transfected with control vector or a vector containing the Shb cDNA. Clones overexpressing Shb were studied with respect to apoptosis (Dapi, M30) and c-Abl activation (Western blot for pY-245-Abl). The cells were exposed to the anti-tumor agent 2-methoxyestradiol (2-ME) and the p38 MAPK and c-Abl inhibitors SB203580 and STI-571, respectively, after which cell death was determined. In vivo tumor growth and tumor cell proliferation (Ki-67 staining) or apoptosis (active caspase 3 staining) were also determined in nude mice.


RESULTS
PC3 cells overexpressing Shb exhibited increased rates of apoptosis in the presence of the anti-tumor agent 2-ME. The Shb cells displayed increased activity of the pro-apoptotic kinase c-Abl. Pre-treatment with p38 MAPK (SB203580) or c-Abl (STI-571) inhibitors completely blocked 2-ME-induced apoptosis, implicating these two pathways in the response. The PC3-Shb cells displayed reduced tumor growth in vivo, an effect occurring as a consequence of increased apoptosis and reduced DNA synthesis.


CONCLUSIONS
It is concluded that Shb promotes 2-ME-induced PC3 cell apoptosis by increased pro-apoptotic signaling via the c-Abl pathway and that this causes reduced tumor growth in vivo.
Davoodpour
Padideh
P
Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden. padideh.davoodpour@ki.se <padideh.davoodpour@ki.se>
Landström
Maréne
M
Welsh
Michael
M
D000077584:2-Methoxyestradiol; D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D015153:Blotting, Western; D049109:Cell Proliferation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004958:Estradiol / Q000031:analogs & derivatives / Q000494:pharmacology; D005260:Female; D006801:Humans; D008297:Male; D051379:Mice; D008819:Mice, Nude; D011471:Prostatic Neoplasms / Q000378:metabolism / Q000473:pathology*; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000378:metabolism*; D016315:Proto-Oncogene Proteins c-abl / Q000378:metabolism*; D015398:Signal Transduction; D014162:Transfection; D050257:Tubulin Modulators / Q000494:pharmacology; D014407:Tumor Cells, Cultured; D015854:Up-Regulation; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
D048868:Adaptor Proteins, Signal Transducing; D004791:Enzyme Inhibitors; D011518:Proto-Oncogene Proteins; C490081:SHB protein, human; D050257:Tubulin Modulators; D004958:Estradiol; D000077584:2-Methoxyestradiol; D016315:Proto-Oncogene Proteins c-abl; D048051:p38 Mitogen-Activated Protein Kinases
Curr Mol Med. 2003 Jun;3(4):313-24
12776987
Carcinogenesis. 2003 Jun;24(6):1067-75
12807754
Nat Rev Mol Cell Biol. 2004 Jan;5(1):33-44
14708008
Urology. 2003 Dec 29;62 Suppl 1:134-40
14747051
Nucl Med Biol. 2004 Oct;31(7):867-74
15464388
Cancer Res. 1992 Nov 1;52(21):5926-32
1327520
Nature. 1994 Mar 17;368(6468):237-9
7511798
Proc Natl Acad Sci U S A. 1994 Apr 26;91(9):3964-8
8171020
Oncogene. 1995 Apr 20;10(8):1475-83
7537362
Nature. 1995 Aug 31;376(6543):785-8
7651539
Oncogene. 1996 Sep 5;13(5):955-61
8806685
Oncogene. 1997 Sep;15(11):1255-62
9315092
Oncogene. 1998 Feb 19;16(7):891-901
9484780
Nature. 1999 Jun 24;399(6738):814-7
10391251
Mol Med. 1999 Mar;5(3):169-80
10404514
J Biol Chem. 1999 Sep 3;274(36):25726-34
10464310
Cancer Res. 2005 Jan 15;65(2):533-9
15695396
J Biol Chem. 2005 Apr 15;280(15):14773-9
15708859
Ann N Y Acad Sci. 2005 Apr;1040:114-22
15891014
Prostate. 2005 Jun 1;63(4):385-94
15617027
J Exp Clin Cancer Res. 2005 Jun;24(2):175-80
16110748
Apoptosis. 2006 Jan;11(1):89-99
16374544
Apoptosis. 2006 Nov;11(11):1969-75
17031491
Exp Cell Res. 2007 Jan 15;313(2):284-91
17112510
Cell. 2000 Oct 13;103(2):239-52
11057897
EMBO J. 2000 Jan 17;19(2):273-81
10637231
J Biol Chem. 2000 Mar 17;275(11):7470-3
10713049
Blood. 2000 Jun 1;95(11):3403-11
10828022
Nature. 2000 Sep 21;407(6802):390-5
11014196
J Biol Chem. 2000 Nov 10;275(45):35631-7
10964922
Biochem Biophys Res Commun. 2000 Nov 30;278(3):537-43
11095946
Mol Cell Biol. 2002 Sep;22(17):6079-88
12167702
FEBS Lett. 2002 Nov 6;531(2):141-51
12417302
Annu Rev Pharmacol Toxicol. 2003;43:199-231
12195027
Mol Biol Cell. 2003 Feb;14(2):529-44
12589052
Cancer Cell. 2003 Apr;3(4):363-75
12726862