Role of galaptin in ovarian carcinoma adhesion to extracellular matrix in vitro

H. J. Allen, D. Sucato, B. Woynarowska, S. Gottstine, A. Sharma, R. J. Bernacki

Research output: Contribution to journalArticle

53 Scopus citations

Abstract

Immunohistochemical studies indicated that galaptin is a major protein of ovarian carcinoma cells present in patient effusions and it is distributed throughout the cytoplasm. Enzyme‐linked immunoadsorbent assay (ELISA) and immunoprecipitation experiments demonstrated that galaptin is also a major protein of the A121 ovarian carcinoma cell line, constituting ≤1% of extractable protein bound by DEAE Sephacel. Western blot analyses revealed that the galaptin present in ovarian carcinoma consists of a 14.5 KD subunit. Ovarian carcinoma and mesothelial cells isolated from patient effusions display surface receptors for galaptin with an apparently greater density of receptors present on the carcinoma cells. A121 cells also display surface receptors for galaptin: binding sites/cell = 3 × 108 and Ka = 1.2 × 109M−1. The presence of galaptin in bovine corneal endothelial cells (BCEC) and BCED‐derived extracellular matrix (ECM)was demonstrated by ELISA. Of the total ECM‐bound galaptin, about 75% appears to be insoluble in phosphate‐buffered saline (PBS) lactose. ECM was also found to contain abundant receptors for galaptin. Treatment of ECM with lactose increased the apparent galaptin receptor density:binding sites/cm2 = 7 × 1013 and Ka = 2.6 × 109 M−1. Pretreatment of A121 cells with galaptin inhibited adhesion to ECM. The addition of exogenous galaptin to ECM had variable effect on cell adhesion. The data presented here suggest that early adhesion events may be carbohydrate‐specific involving interaction between ECM‐bound galaptin and cell surface galaptin receptors.

Original languageEnglish (US)
Pages (from-to)43-57
Number of pages15
JournalJournal of Cellular Biochemistry
Volume43
Issue number1
DOIs
StatePublished - May 1990

Keywords

  • beta‐galactoside
  • cell adhesion
  • endogenous lectin
  • extracellular matrix
  • ovarian carcinoma
  • receptors

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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