Neuroblastoma cells express c-sis and produce a transforming growth factor antigenically related to the platelet-derived growth factor.

Abstract

Mouse neuroblastoma Neuro-2A cells produce transforming growth factors during exponential growth in a defined hormone-free medium, which, on Bio-Gel columns in 1 M HAc, elute at a molecular size of 15 to 20 kilodaltons (kDa). These neuroblastoma-derived transforming growth factors have strong mitogenic activity, but they do not compete with epidermal growth factor for receptor binding (E. J. J. van Zoelen, D. R. Twardzik, T. M. J. van Oostwaard, P. T. van der Saag, S. W. de Laat, and G. J. Todaro, Proc. Natl. Acad. Sci. U.S.A. 81:4085-4089, 1984). In this study approximately 80% of the mitogenic activity was immunoprecipitated by antibodies raised against platelet-derived growth factor (PDGF). Immunoblotting indicated a true molecular size of 32 kDa for this PDGF-like growth factor. Analysis of poly(A)+ RNA from Neuro-2A cells demonstrated the expression of the c-sis oncogene in this cell line, whereas in vitro translation of the RNA yielded a 20-kDa protein recognized by anti-PDGF antibodies. Separation by reverse-phase high-pressure liquid chromatography demonstrated the presence of two distinct mitogenic activities in neuroblastoma-derived transforming growth factor preparations, one of which is antigenically related to PDGF. Both activities had the ability to induce anchorage-independent growth in normal rat kidney cells, both in the presence and in the absence of epidermal growth factor. It is concluded that Neuro-2A cells express c-sis with concomitant production and secretion of a PDGF-like growth factor, which plays a role in the induction of phenotypic transformation on normal rat kidney cells.

Differentially regulated production of platelet-derived growth factor and of transforming growth factor beta by a human teratocarcinoma cell line

“…CM-2-SW fractions, containing mitogenic activity and prepared as described above, were analyzed under nonreducing conditions using a discontinuous sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS/PAGE) system (5% stacking gel; 12.5% resolving gel), as described by Laemmli [25]. Gels were blotted overnight onto nitrocellulose paper (4" C ; 30-35 mV; 100 mA) and antigen-antibody complexes were visualized by a modification of the method of Towbin et al 1441 as described by van Zoelen et al [50], using a specific rabbit antiserum raised against pure human PDGF (kindly provided by Dr.…”

Anti-migratory and Anti-invasive Effect of Somatostatin in Human Neuroblastoma Cells

“…Among these, platelet-derived growth factor (PDGF), 1 a mitogen mostly for cells of mesenchymal origin, was shown to induce chemotaxis and actin reorganization and prevent cells from dying by apoptosis (2). As a variety of other neural crest-derived tumor cell lines, neuroblastoma cells express specific transcripts of PDGF genes and both ␣-and ␤-PDGF receptor genes (3,4). It is feasible that the simultaneous presence of PDGF and its receptor genes contributes to tumor cell growth and motility by means of an autocrine mechanism.…”

Structural characterization of the human platelet-derived growth factor A-chain cDNA and gene: alternative exon usage predicts two different precursor proteins.

“…The B-chain gene is the normal cellular homolog to the v-sis oncogene of simian sarcoma virus (SSV) (7,13,29,31,53) (and therefore denoted sis) and is situated on the short arm of human chromosome 22 (4,11,48). A 4.0-kilobase (kb) PDGF-B/sis transcript has been detected in a variety of human tumor cell lines (14,19,37,52) as well as in endothelial cells (3,9,25), placental cytotrophoblasts (18), and activated macrophages (35,46). Both the B-chain/sis gene and v-sis encode a precursor molecule with a hydrophobic N-terminus characteristic of a signal peptide.…”