The transition from prostatic intrepithelial neoplasia (PIN) to invasive carcinoma is characterized by a loss of two major regulatory proteins, beta4 integrin and its ligand, laminin 5. We hypothesize that the mechanism for the loss of laminin 5 is the presence of a post-transcriptional defect. The failure of laminin 5 assembly causes instability of beta4 which is lost due to degradation. The loss of these regulatory proteins destabilizes the normal signaling pathway of the cells contributing to prostate tumor progression. We will examine this hypothesis by using the LNCaP cell line which, like the primary prostate carcinomas, expresses the three laminin subchain mRNAs but fails to assemble the fully functioning heterotrimeric laminin 5 protein.
In Aim 1 we will examine the three laminin 5 subchain mRNAs for mutations by sequencing fragments of the cDNA products produced by RT-PCR. The mRNAs will also be tested for their in vitro translational capacity.
In Aim 2 we will test the effect the purified laminin 5 on the synthesis, degradation, and cytoplasmic membrane stability of beta4 integrin. We will also study the ability of purified laminin 5 to cause signal transduction. These experiments will utilize pulse labeling or surface biotinylation followed by immunoprecipitation, and in the cause of signal transduction, Western blotting with anti-phosphotyrosine, Sh2, and GrB2 specific antibodies. The functional effect of laminin 5 on prostrate cell growth, adhesion, migration, and tumorigenicity will also be studied in Aim 3. These studies will be carried out using quantitative assays of adhesion and migration established in our laboratory.
In Aim 4 we will test the clinical relevance of the persistence of alpha 6 and alpha 3 integrins in the absence of beta4.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Program Projects (P01)
Project #
5P01CA056666-06
Application #
6300434
Study Section
Project Start
2000-04-01
Project End
2001-03-31
Budget Start
1998-10-01
Budget End
1999-09-30
Support Year
6
Fiscal Year
2000
Total Cost
$139,797
Indirect Cost
Name
University of Arizona
Department
Type
DUNS #
City
Tucson
State
AZ
Country
United States
Zip Code
85721
Nagle, Raymond B; Algotar, Amit M; Cortez, Connie C et al. (2013) ERG overexpression and PTEN status predict capsular penetration in prostate carcinoma. Prostate 73:1233-40
Sroka, Isis C; Sandoval, Cynthia P; Chopra, Harsharon et al. (2011) Macrophage-dependent cleavage of the laminin receptor ?6?1 in prostate cancer. Mol Cancer Res 9:1319-28
Sroka, Isis C; Anderson, Todd A; McDaniel, Kathy M et al. (2010) The laminin binding integrin alpha6beta1 in prostate cancer perineural invasion. J Cell Physiol 224:283-8
Sroka, Isis C; Pond, Gerald D; Nagle, Raymond B et al. (2009) Human Cell Surface Receptors as Molecular Imaging Candidates for Metastatic Prostate Cancer. Open Prost Cancer J 2:59-66
Ports, Michael O; Nagle, Ray B; Pond, Gerald D et al. (2009) Extracellular engagement of alpha6 integrin inhibited urokinase-type plasminogen activator-mediated cleavage and delayed human prostate bone metastasis. Cancer Res 69:5007-14
Sroka, Isis C; McDaniel, Kathy; Nagle, Raymond B et al. (2008) Differential localization of MT1-MMP in human prostate cancer tissue: role of IGF-1R in MT1-MMP expression. Prostate 68:463-76
Demetriou, Manolis C; Kwei, Kevin A; Powell, Marianne B et al. (2008) Integrin A6 Cleavage in Mouse Skin Tumors. Open Cancer J 2:1-4
Sroka, Isis C; Chen, Man Ling; Cress, Anne E (2008) Simplified purification procedure of laminin-332 and laminin-511 from human cell lines. Biochem Biophys Res Commun 375:410-3
Moran, Carlos M; Garriock, Robert J; Miller, Melanie K et al. (2008) Expression of the fast twitch troponin complex, fTnT, fTnI and fTnC, in vascular smooth muscle. Cell Motil Cytoskeleton 65:652-61
King, Tamara E; Pawar, Sangita C; Majuta, Lisa et al. (2008) The role of alpha 6 integrin in prostate cancer migration and bone pain in a novel xenograft model. PLoS One 3:e3535

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