Significance of integrin α5β1 in the prostate cancer DU145 cell line interaction with fibronectin
Article published in Urologia Polska 2008/61/Supl. 1.

authors

Magdalena Kieliszek, Hanna M. Kowalczyńska

Zakład Biofizyki, Centrum Medyczne Kształcenia Podyplomowego w Warszawie

summary

Introduction.

The knowledge of the correlation between adhesion, migration, and proliferation of cancer cells interacting with proteins of the extracellular matrix (ECM) is fundamental in the study of cancer metastasis formation. One of the important ECM proteins is fibronectin (FN). This glycoprotein contains cell binding domain with amino acid sequence Arg-Gly-Asp (RGD), recognized by surface cell receptors. The main FN receptor is α5β1 integrin. The interactions of the prostate cancer cells DU145 cells, derived from the metastases to the brain, with fibronectin and α5β1 integrin participation during this interaction have not been as yet described in detail.

Objectives.

The aim of our experiments was to estimate the integrin α5β1 significance in adhesion, spreading, migration, and proliferation the prostate cancer DU145 cells interacting with fibronectin in vitro.

Materials and methods.

Flow cytometry analysis determining the presence of integrins characteristic of FN on prostate cancer DU145 cell surfaces. To estimate the significance of integrin α5β1 the whole molecule or only its α5 integrin subunits were blocked by specific monoclonal antibodies. We observed cells interacting with FN adsorbed on sulfonated polystyrene surfaces using automatic, sequentional microscopic image registration, which made it possible to make long-time observation of the migration, changes in cell shape and cell proliferation. We measured adhesion under static conditions and spreading dynamics of cells interacting with fibronectin; the results were statistically analyzed. We also investigated cell migration and proliferation. We estimated the patterns of cytoskeletal proteins organization (F-actin, actinin and tubulin)

in the adhered cells, with the use of an image analysis method.

Results.

Our results concerning the interaction of the prostate cancer DU145 cells with fibronectin adsorbed on sulfonated polystyrene surfaces are as follows: 1. The α5β1, αvβ3 and α3β1 integrins, specific to interactions with FN, are present on the cell surface. 2. The adhesion and spreading dynamics of cells interacting with FN are very high. 3. The cells interacting with FN exhibit the ability to migrate and proliferate. 4. Spreading dynamics of cells depends on the FN concentration, in the range of protein concentration studied (5-20μg/ml). 5. The blocking of integrin α5β1 or only α5 subunits present on the cell surface cause a reduction in cell spreading dynamics and lead to significantly lower cytoskeletal reorganization as compared with control cells.

Conclusions.

Our results prove the significant role of α5β1 integrin in adhesion, spreading, migration and proliferation of the prostate cancer DU145 cells interacting with fibronectin, and suggest that this interaction can play a significant role in metastatic processes of prostate cancer cells. This study was supported by CMKP grant No. 501-2-1-23-26/05