Our long-term objectives are to elucidate the mechanisms by which fetuin-A, a serum glycoprotein synthesized by the liver, mediates and regulates the in vitro and in vivo growth of tumor cells. The central hypothesis is that fetuin-A derived from the serum or synthesized by the tumor cells interacts with its putative cell surface receptors, triggering PI3 kinase/Akt signaling that drives the growth of the cells. The hypothesis will be investigated through 4 specific aims: (1) To define the cell surface receptors for fetuin-A in tumor cells responsible for growth signaling; (2) To determine other signaling pathways which are modulated in tumor cells by the annexin/fetuin-A interaction; (3) To elucidate the role of ectopically synthesized fetuin-A in tumor cell growth; and (4) To define the specificity of serum derived fetuin-A in tumor growth promotion. ? ? In aim 1, we will extend our studies that were done on a limited scale using LLC cells to LNCaP prostate cancer cell line transfected with annexin-2-GFP. The co-localization and interaction between annexin-2 and fetuin-A in these cells will be studied using confocal microscopy. It is expected that annexins will emerge as the cell surface receptors for fetuin-A responsible for growth signaling.
In aim 2, Kinexus and Affymetrix gene arrays will be used to screen for other signaling molecules whose expression is affected by the fetuin-A/annexin interaction. A number of signaling pathways cross-talk with the PI3 kinase/Akt pathway that is predominantly activated by fetuin-A.
In aim 3, fetuin-A gene will be added back to cells that do not express it to determine if this is sufficient to allow these cells to grow under serum-free conditions and in fetuin-A null mice. Likewise, fetuin-A expression in LLC cells will be knocked down by sh-RNA approach and their growth under serum-free conditions re-evaluated.
In aim 4, the serum from fetuin-A wild-type animals will be used to supplement growth medium to determine its growth promoting abilities in a variety of tumor cells vis-a-vis growth medium supplemented with serum from fetuin-A null mice. In this aim, we will determine whether the unique ability of fetuin-A to promote cell growth is also dictated by its amino acid sequence and not merely the presence of sialic acid residues. This proposal seeks to demonstrate that fetuin-A is an important fuel for the in vivo growth of tumor cells and is not an innocent bystander. The full understanding of this pathway has broad implications in the management and treatment strategies for majority of cancer types. ? ? ?

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Enhancement Award (SC1)
Project #
1SC1CA134018-01
Application #
7289952
Study Section
Special Emphasis Panel (ZGM1-MBRS-7 (SC))
Program Officer
Wali, Anil
Project Start
2007-09-19
Project End
2011-08-31
Budget Start
2007-09-19
Budget End
2008-08-31
Support Year
1
Fiscal Year
2007
Total Cost
$366,250
Indirect Cost
Name
Meharry Medical College
Department
Biochemistry
Type
Schools of Medicine
DUNS #
041438185
City
Nashville
State
TN
Country
United States
Zip Code
37208
Thompson, Pamela D; Sakwe, Amos; Koumangoye, Rainelli et al. (2014) Alpha-2 Heremans Schmid Glycoprotein (AHSG) modulates signaling pathways in head and neck squamous cell carcinoma cell line SQ20B. Exp Cell Res 321:123-32
Nangami, Gladys; Koumangoye, Rainelli; Shawn Goodwin, J et al. (2014) Fetuin-A associates with histones intracellularly and shuttles them to exosomes to promote focal adhesion assembly resulting in rapid adhesion and spreading in breast carcinoma cells. Exp Cell Res 328:388-400
Nangami, Gladys N; Watson, Kurt; Parker-Johnson, Kitani et al. (2013) Fetuin-A (?2HS-glycoprotein) is a serum chemo-attractant that also promotes invasion of tumor cells through Matrigel. Biochem Biophys Res Commun 438:660-5
Watson, Kurt; Koumangoye, Rainelli; Thompson, Pamela et al. (2012) Fetuin-A triggers the secretion of a novel set of exosomes in detached tumor cells that mediate their adhesion and spreading. FEBS Lett 586:3458-63
Sakwe, Amos M; Koumangoye, Rainelli; Guillory, Bobby et al. (2011) Annexin A6 contributes to the invasiveness of breast carcinoma cells by influencing the organization and localization of functional focal adhesions. Exp Cell Res 317:823-37
Koumangoye, Rainelli B; Sakwe, Amos M; Goodwin, J Shawn et al. (2011) Detachment of breast tumor cells induces rapid secretion of exosomes which subsequently mediate cellular adhesion and spreading. PLoS One 6:e24234
Sakwe, Amos M; Koumangoye, Rainelli; Goodwin, Shawn J et al. (2010) Fetuin-A ({alpha}2HS-glycoprotein) is a major serum adhesive protein that mediates growth signaling in breast tumor cells. J Biol Chem 285:41827-35
Ochieng, Josiah; Pratap, Siddharth; Khatua, Atanu K et al. (2009) Anchorage-independent growth of breast carcinoma cells is mediated by serum exosomes. Exp Cell Res 315:1875-88