title: Downregulation of FIP200 induces apoptosis of glioblastoma cells and microvascular endothelial cells by enhancing Pyk2 activity.
abstract: The expression of focal adhesion kinase family interacting protein of 200-kDa (FIP200) in normal brain is limited to some neurons and glial cells. On immunohistochemical analysis of biopsies of glioblastoma tumors, we detected FIP200 in the tumor cells, tumor-associated endothelial cells, and occasional glial cells. Human glioblastoma tumor cell lines and immortalized human astrocytes cultured in complete media also expressed FIP200 as did primary human brain microvessel endothelial cells (MvEC), which proliferate in culture and resemble reactive endothelial cells. Downregulation of endogenous expression of FIP200 using small interfering RNA resulted in induction of apoptosis in the human glioblastoma tumor cells, immortalized human astrocytes, and primary human brain MvEC. It has been shown by other investigators using cells from other tissues that FIP200 can interact directly with, and inhibit, proline-rich tyrosine kinase 2 (Pyk2) and focal adhesion kinase (FAK). In the human glioblastoma tumor cells, immortalized human astrocytes, and primary human brain MvEC, we found that downregulation of FIP200 increased the activity of Pyk2 without increasing its expression, but did not affect the activity or expression of FAK. Coimmunoprecipitation and colocalization studies indicated that the endogenous FIP200 was largely associated with Pyk2, rather than FAK, in the glioblastoma tumor cells and brain MvEC. Moreover, the pro-apoptotic effect of FIP200 downregulation was inhibited significantly by a TAT-Pyk2-fusion protein containing the Pyk2 autophosphorylation site in these cells. In summary, downregulation of endogenous FIP200 protein in glioblastoma tumor cells, astrocytes, and brain MvECs promotes apoptosis, most likely due to the removal of a direct interaction of FIP200 with Pyk2 that inhibits Pyk2 activation, suggesting that FIP200 expression may be required for the survival of all three cell types found in glioblastoma tumors.
authors: Division of Neuropathology, Department of Pathology, University of Alabama at Birmingham, Birmingham, Alabama, United States of America.
authors: Dongyan
authors: D
authors: Wang
authors: Mitchell A
authors: MA
authors: Olman
authors: Jerry
authors: J
authors: Stewart
authors: Russell
authors: R
authors: Tipps
authors: Ping
authors: P
authors: Huang
authors: Paul W
authors: PW
authors: Sanders
authors: Eric
authors: E
authors: Toline
authors: Richard A
authors: RA
authors: Prayson
authors: Jeongwu
authors: J
authors: Lee
authors: Robert J
authors: RJ
authors: Weil
authors: Cheryl A
authors: CA
authors: Palmer
authors: G Yancey
authors: GY
authors: Gillespie
authors: Wei Michael
authors: WM
authors: Liu
authors: Russell O
authors: RO
authors: Pieper
authors: Jun-Lin
authors: JL
authors: Guan
authors: Candece L
authors: CL
authors: Gladson
references: J Cell Sci. 2000 Dec;113 Pt 23:4221-30
references: 11069767
references: J Cell Biol. 2005 Aug 1;170(3):379-89
references: 16043512
references: Mol Cell Biol. 2004 May;24(10):4361-71
references: 15121855
references: J Biol Chem. 2004 Dec 17;279(51):53516-23
references: 15322113
references: J Cell Biol. 2000 Apr 17;149(2):423-30
references: 10769033
references: Mol Biol Cell. 2001 Dec;12(12):4066-77
references: 11739801
references: Cancer Res. 2002 Nov 1;62(21):6045-51
references: 12414627
references: Nat Genet. 2002 Jul;31(3):285-8
references: 12068296
references: Nat Med. 1998 Dec;4(12):1449-52
references: 9846587
references: J Exp Med. 2003 Jan 6;197(1):63-75
references: 12515814
references: Oncogene. 2006 Mar 16;25(12):1721-32
references: 16288224
references: Int J Oncol. 1998 Apr;12(4):811-6
references: 9499440
references: Oncogene. 2002 Feb 14;21(8):1295-8
references: 11850849
references: J Cell Physiol. 2009 Jan;218(1):94-103
references: 18726995
references: J Biol Chem. 2009 Feb 27;284(9):6004-13
references: 19106106
references: Cell Signal. 2008 May;20(5):787-94
references: 18036779
references: J Biol Chem. 2001 Jan 19;276(3):2189-99
references: 11053415
references: J Cell Biochem. 2006 Sep 1;99(1):35-52
references: 16823799
references: J Biol Chem. 2010 Jan 29;285(5):3499-509
references: 19940130
references: Cell Stem Cell. 2009 May 8;4(5):440-52
references: 19427293
references: Cancer Res. 2005 Jul 1;65(13):5535-43
references: 15994925
references: Gene. 2002 May 29;291(1-2):29-34
references: 12095676
references: Acta Neuropathol. 2007 Aug;114(2):97-109
references: 17618441
references: Oncogene. 1999 Nov 18;18(48):6733-40
references: 10597281
references: J Biol Chem. 2005 Feb 25;280(8):6802-15
references: 15557280
references: J Cell Biol. 2006 Oct 9;175(1):121-33
references: 17015619
references: J Biol Chem. 2003 Oct 10;278(41):39882-91
references: 12881526
references: J Cell Sci. 2000 Sep;113 ( Pt 17):3063-72
references: 10934044
references: J Biol Chem. 2004 Aug 6;279(32):33315-22
references: 15166227
references: Semin Thromb Hemost. 2010 Apr;36(3):321-31
references: 20490982
references: Biochem Biophys Res Commun. 2009 Jun 5;383(3):347-52
references: 19358827
references: Mol Cancer Res. 2003 Mar;1(5):323-32
references: 12651906
references: Physiol Rev. 2004 Oct;84(4):1315-39
references: 15383653
references: Mol Cell. 2003 Jun;11(6):1503-15
references: 12820964
references: Cell Signal. 2000 Mar;12(3):123-33
references: 10704819
references: J Cell Biol. 2003 Feb 17;160(4):565-75
references: 12578912
references: J Interferon Cytokine Res. 2005 Dec;25(12):749-56
references: 16375603
references: J Cell Biol. 2008 May 5;181(3):497-510
references: 18443221
references: Cancer Res. 2009 Jul 1;69(13):5537-45
references: 19549899
references: J Biol Chem. 2000 Jun 30;275(26):19768-77
references: 10764815
references: Cancer Res. 2005 Aug 1;65(15):6676-84
references: 16061648
references: Am J Physiol Renal Physiol. 2008 Aug;295(2):F406-14
references: 18562633
references: Acta Neuropathol. 2004 Sep;108(3):224-30
references: 15221336
references: Cancer Res. 2001 Jul 1;61(13):4956-60
references: 11431323
references: Mol Biol Cell. 2002 Sep;13(9):3178-91
references: 12221124
references: J Biol Chem. 1999 Apr 9;274(15):10140-4
references: 10187797
references: J Cell Biol. 1997 Oct 20;139(2):529-39
references: 9334354
references: Clin Cancer Res. 2007 Jul 15;13(14):4051-60
references: 17634529
references: Endocrinology. 2004 Jul;145(7):3324-30
references: 15070849
references: PLoS One. 2010 Jun 30;5(6):e11404
references: 20614030
references: Int J Cancer. 2009 Aug 15;125(4):861-7
references: 19437535