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Clin Exp Metastasis. 1997 Jan;15(1):41-52.

Transforming growth factor beta upregulates the integrin-mediated adhesion of human prostatic carcinoma cells to type I collagen.

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Department of Pathology, McMaster University, Hamilton, Ontario, Canada.


Prostate cancer frequently metastasizes to bone, and we propose that this process may be facilitated by the adhesion of metastatic cells to bone-derived type I collagen. We examined collagen receptor function and regulation in osteotropic PC-3 human prostatic carcinoma cells. PC-3 cell adhesion to immobilized human type I collagen was promoted by Mn2+ and Mg2+ ions and was RGD-independent. Antibodies directed against beta1 or alpha2 integrin subunits inhibited adhesion to collagen by 90% and 53%, respectively, suggesting involvement of the alpha2 beta1 receptor. Anti-alpha1 or anti-alpha3 antibodies had no effect on adhesion. Flow cytometry and immunoprecipitation of [35S]methionine-labeled cells demonstrated that alpha2 beta1 was the major collagen receptor expressed by PC-3 cells. The pretreatment of PC-3 cells with transforming growth factor-beta1 (TGF-beta1), a major bone-derived growth factor, caused a rapid (2 h) 2-fold increase in the de novo synthesis of alpha2 and beta1 integrin subunits, and also increased by 2- to 3-fold the adhesion and spreading of PC-3 cells on collagen. We conclude that alpha2 beta1 is the major collagen receptor employed by PC-3 cells, and that alpha2 beta1 upregulation by TGF-beta is associated with an increased adhesion and spreading on collagen. The data suggest that exposure of metastatic PC-3 cells to the high levels of TGF-beta in bone may promote their ability to adhere to bone-derived collagen, which may thereby facilitate the localization of metastatic cells in the skeleton.

[Indexed for MEDLINE]

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