Production of insulin-like growth factor binding proteins by small-cell lung cancer cell lines

Journal Article · Sun Oct 01 00:00:00 EDT 1989 · Experimental Cell Research; (United States)

DOI:https://doi.org/10.1016/0014-4827(89)90339-X· OSTI ID:5622996

Jaques, G; Kiefer, P; Rotsch, M; Hennig, C; Goeke, R; Richter, G; Havemann, K ^[1]

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1. Baldingerstrasse, Marburg (West Germany)

Conditioned serum-free media (CM) from small-cell lung cancer (SCLC) cell lines were examined for the presence of insulin-like growth-factor-binding proteins (IGF-BP). 6/9 SCLC cell lines secreted binding proteins with high affinity for IGFs. When ({sup 125}I)IGF-1 or ({sup 125}I)IGF-II was incubated with the CMs, complexes of tracer with proteins could be demonstrated by gel filtration, by precipitation with polyethylenglycol, and after adsorption of unbound tracer with activated charcoal. Analysis of binding data according to the method of Scatchard resulted in linear plots for IGF-I and IGF-II. Cross-linking of ({sup 125}I)IGF-I or ({sup 125}I)IGF-II to the CMs followed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) under nonreducing conditions revealed the presence of IGF-BPs with molecular masses in the range of 24-32 kDa. Northern blot hybridization with an IGF-BP cDNA probe encoding a low-molecular-weight IGF-BP from a human placenta cDNA library and Western blot analysis with a corresponding polyclonal antibody showed no expression of this gene. These data demonstrate that SCLC cell lines release IGF-BPs in culture supernatants, which differ from IGF-BPs detected in liver and placenta. These IGF-BPs might be important mediators in the autocrine/paracrine growth regulation of IGFs in SCLC.

• OSTI ID: 5622996
• Journal Information: Experimental Cell Research; (United States), Vol. 184:2; ISSN 0014-4827
• Country of Publication: United States
• Language: English

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TUMOR CELLS
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MITOGENS
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NUCLEIC ACIDS
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ORGANS
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550301* - Cytology- Tracer Techniques