Regulation of breast cancer cell motility by T-cell lymphoma invasion and metastasis-inducing protein.
BACKGROUND
T-cell lymphoma invasion and metastasis-inducing protein (Tiam1) is a Ras-related C3 botulinum toxin substrate (Rac)-specific guanine nucleotide exchange factor that was isolated based on its ability to induce a metastatic phenotype. In polarized migrating keratinocytes, Tiam1 is found at the leading edge where it cooperates with the Protease-activated receptor 1 (Par1) complex to establish front-rear polarity. Although a positive correlation has been observed between Tiam1 expression and tumor grade in a variety of human malignancies, including breast, its role in breast cancer cells has not yet been examined.


METHODS
Tiam1 expression and Rac activity were examined in a panel of human breast cancer cell lines which exhibit different degrees of cell motility. The contribution of Tiam1 to cell motility was directly examined using transwell motility, and wound healing assays.


RESULTS
Although we observe a striking, positive correlation between Tiam1 expression and cell motility in the panel of breast cancer cell lines, we do not observe a correlation between Tiam1 expression and overall levels of Rac activity. Consistent with this, small interfering ribonucleic acid (siRNA)-mediated suppression of Tiam1 expression limits the motility of cell lines in which Tiam1 expression is high (MDA-MB-231 and MDA-MB-453), but does not substantially alter the overall levels of activated Rac. Tiam1 overexpression is also not sufficient to increase the motility of more poorly motile cells (T-47D) or increase Rac activity. Immunofluorescence and cellular fractionations indicate that Tiam1 is found predominantly in the Golgi of breast cancer cells, and in the latter case Tiam1 was shown to co-fractionate with a limited pool of Rac1. Consistent with this Golgi localization, Tiam1 supports cell motility and Golgi reorientation in response to serum in a wound healing assay using MDA-MB-231and MDA-MB-435S cells.


CONCLUSIONS
Tiam1 expression correlates with cell motility in human breast cancer cells, and is required to support the motile phenotype. Localization of endogenous Tiam1 to the Golgi, and its demonstrated role in Golgi reorientation, suggest that it may support motility through a mechanism that is discrete from its known function in leading edge dynamics.
Adams
Homer C
HC
Department of Microbiology and Molecular Genetics, University Hospital Cancer Center, University of Medicine and Dentistry of New Jersey, Newark, 07101-1709, USA.
Chen
Ru
R
Liu
Zhuoming
Z
Whitehead
Ian P
IP
D001943:Breast Neoplasms / Q000378:metabolism* / Q000473:pathology*; D045744:Cell Line, Tumor; D002465:Cell Movement; D005260:Female; D006056:Golgi Apparatus / Q000378:metabolism; D020662:Guanine Nucleotide Exchange Factors / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D009361:Neoplasm Invasiveness; D034622:RNA Interference; D034741:RNA, Small Interfering; D044463:Receptor, PAR-1 / Q000378:metabolism; D015398:Signal Transduction; D000075684:T-Lymphoma Invasion and Metastasis-inducing Protein 1; D020764:cdc42 GTP-Binding Protein / Q000235:genetics; D020744:rac GTP-Binding Proteins / Q000378:metabolism*
D020662:Guanine Nucleotide Exchange Factors; D034741:RNA, Small Interfering; D044463:Receptor, PAR-1; D000075684:T-Lymphoma Invasion and Metastasis-inducing Protein 1; C087334:TIAM1 protein, human; D020764:cdc42 GTP-Binding Protein; D020744:rac GTP-Binding Proteins
Mod Pathol. 2008 May;21(5):544-52
18246045
Genes Dev. 2002 Jul 1;16(13):1587-609
12101119
Cell. 2005 May 6;121(3):451-63
15882626
Oncogene. 1995 Dec 7;11(11):2215-21
8570171
Br J Cancer. 2006 Oct 23;95(8):1081-6
17003780
Curr Opin Cell Biol. 2002 Aug;14(4):428-33
12383793
J Cell Biol. 2005 Sep 26;170(7):1029-37
16186252
Cancer Res. 2006 Jun 15;66(12):6250-7
16778200
Oncogene. 1995 Apr 6;10(7):1371-6
7731688
Oncogene. 2005 Apr 7;24(15):2568-73
15735692
Proc Natl Acad Sci U S A. 1992 Jun 15;89(12):5321-5
1351679
Breast Cancer Res Treat. 2004 Mar;84(1):21-32
14999151
Oncol Rep. 2009 Jan;21(1):217-22
19082465
Curr Opin Lipidol. 2008 Oct;19(5):462-8
18769227
Cell Signal. 1999 Aug;11(8):545-54
10433515
Biochem J. 2000 Jun 1;348 Pt 2:241-55
10816416
Nat Rev Cancer. 2003 May;3(5):362-74
12724734
Nat Cell Biol. 2003 Jul;5(7):599-609
12833063
Curr Opin Cell Biol. 2005 Oct;17(5):533-41
16099638
Clin Exp Metastasis. 2006;23(5-6):301-13
17086355
Curr Opin Cell Biol. 2003 Oct;15(5):590-7
14519394
ORL J Otorhinolaryngol Relat Spec. 2009;71(3):163-71
19506399
Methods Enzymol. 2001;333:256-66
11400341
Nature. 2002 Dec 12;420(6916):629-35
12478284
Nature. 2008 May 15;453(7193):314-21
18480812
Nature. 1997 Dec 11;390(6660):632-6
9403696
Traffic. 2001 Oct;2(10):717-26
11576448
J Cancer Res Clin Oncol. 2009 Jan;135(1):69-80
18592271
Int J Cancer. 2000 Nov 1;88(3):369-76
11054665
Trends Cell Biol. 2006 Jun;16(6):308-16
16650994
Science. 2000 Oct 13;290(5490):333-7
11030651
Trends Cell Biol. 2005 Mar;15(3):138-45
15752977
J Biol Chem. 2006 Jan 6;281(1):543-8
16249175
EMBO J. 2001 May 1;20(9):2171-9
11331583
Cancer Res. 2009 Jul 1;69(13):5292-3
19549886
FEBS Lett. 2003 Jul 3;546(1):11-6
12829230
Mol Cancer Res. 2007 Feb;5(2):195-201
17314276
Curr Opin Genet Dev. 2005 Feb;15(1):87-96
15661538
J Biol Chem. 2003 May 23;278(21):18833-41
12531897
Annu Rev Cell Dev Biol. 2005;21:247-69
16212495
J Biol Chem. 2001 Jul 27;276(30):28443-50
11328805
Nat Immunol. 2005 Dec;6(12):1182-90
16369557
Science. 2003 Dec 5;302(5651):1704-9
14657486
Nature. 1995 May 25;375(6529):338-40
7753201
Hum Mol Genet. 2003 Oct 1;12(19):2449-56
12915445
Curr Biol. 2007 Oct 9;17(19):1623-34
17825562
J Cell Biol. 1998 Dec 14;143(6):1485-503
9852146
Nat Rev Cancer. 2002 Jun;2(6):442-54
12189386
J Cell Biol. 1997 Apr 21;137(2):387-98
9128250
Eur J Cell Biol. 1998 May;76(1):9-17
9650778
J Biol Chem. 2000 Mar 31;275(13):9742-8
10734127
Curr Protoc Cell Biol. 2001 May;Chapter 3:Unit 3.9
18228361
Cell. 1996 Feb 9;84(3):359-69
8608589
World J Gastroenterol. 2005 Feb 7;11(5):705-7
15655826
Exp Eye Res. 2006 Dec;83(6):1446-52
17027002
Breast Cancer Res Treat. 2007 Jul;104(1):13-9
17004106
Ann N Y Acad Sci. 2006 Dec;1092:385-96
17308163
Dev Cell. 2009 Feb;16(2):196-208
19217422
Nat Cell Biol. 2002 Aug;4(8):621-5
12134164
Biochim Biophys Acta. 1997 Feb 22;1332(1):F1-23
9061011
Cell. 1994 May 20;77(4):537-49
7999144
Mol Biol Cell. 2002 Mar;13(3):866-79
11907268
Int J Cancer. 2009 Feb 1;124(3):653-8
18972435
Nat Cell Biol. 1999 May;1(1):8-13
10559857
Oncogene. 2002 Jul 11;21(30):4601-12
12096337
Biochim Biophys Acta. 2003 Mar 17;1603(2):47-82
12618308
Nature. 2002 Jun 20;417(6891):867-71
12075356