Clinical & Experimental Metastasis

, Volume 7, Issue 3, pp 265–276

Characterization of thrombospondin synthesis, secretion and cell surface expression by human tumor cells

  • James Varani
  • Bruce L. Riser
  • Lisa A. Hughes
  • Thomas E. Carey
  • Suzanne E. G. Fligiel
  • Vishva M. Dixit
Article

DOI: 10.1007/BF01753679

Cite this article as:
Varani, J., Riser, B.L., Hughes, L.A. et al. Clin Exp Metast (1989) 7: 265. doi:10.1007/BF01753679

Abstract

Previous studies have shown that thrombospondin (TSP) is an adhesion factor for some human tumor cells. The previous studies have shown further that tumor cells which utilize TSP as an adhesion factor also synthesize it. This study continues the effort to understand how TSP production and expression are regulated in human tumor cells and the consequences of this for the cells. It is shown that differences among cell lines in their capacity to biosynthesize TSP are associated with differences in TSP specific mRNA levels. This indicates that biosynthesis is regulated at the transcriptional level. There is also a direct relationship between TSP biosynthesis and secretion into the culture medium and expression at the cell surface. The cells which are the most biosynthetically active secrete amounts of TSP into the culture medium that are sufficient to elicit a detectable response in the cell-substrate adhesion assay. The kinetics of TSP secretion by these cells are in accord with the kinetics of attachment and spreading of the same cells in the absence of exogenous adhesion factors. These data are consistent with the idea that endogenously produced TSP promotes the adhesion of the cells which synthesize it in an autocrine manner.

Copyright information

© Taylor & Francis Ltd. 1989

Authors and Affiliations

  • James Varani
    • 1
  • Bruce L. Riser
    • 1
  • Lisa A. Hughes
    • 1
  • Thomas E. Carey
    • 2
  • Suzanne E. G. Fligiel
    • 3
  • Vishva M. Dixit
    • 1
  1. 1.Department of PathologyUniversity of Michigan Medical SchoolAnn ArborUSA
  2. 2.Department of OtolaryngologyUniversity of Michigan Medical SchoolAnn ArborUSA
  3. 3.Department of PathologyVAMC-Wayne State UniversityAllen ParkUSA

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