Simultaneous production of IGF-I and EGF competing growth factors by HT-29 human colon cancer line
✍ Scribed by Jean-Michel Culouscou; Maryse Remacle-Bonnet; Françoise Garrouste; Jacques Marvaldi; Gilbert Pommier
- Publisher
- John Wiley and Sons
- Year
- 1987
- Tongue
- French
- Weight
- 745 KB
- Volume
- 40
- Category
- Article
- ISSN
- 0020-7136
No coin nor oath required. For personal study only.
✦ Synopsis
The conditioned medium from the HT-29 human colonic adenocarcinoma cell line contains a potent mitogenic activity that can markedly stimulate the proliferation of both rat and human fibroblasts in the absence of serum. Fractionation of conditioned medium on Bio-Gel P-100 shows that HT-29 cells simultaneously produce 2 different types of endogenous growth factors. The first one (molecular mass of 35, 8 and 5.5 kDa) exhibits an IGF-l competing activity which is positively correlated to mitogenic activity. This mitogen is recognized by anti-IGF-l antibodies but is resistant to reducing agents. It is distinct from IGF-11, insulin and PDGF. The second one (molecular mass of 40and 20 -kDa) is able to displace EGF binding to i t s receptor. This factor is immunologically recog nized by anti-EGF antibodies but with a lower affinity as compared to EGF. This suggests that this endogenous HT-29growth factor is related to but distinct from native EGF. Although more active in radioreceptor assay than in radioimmunoassay, the EGF-competing factor is distinct from TGF a or 0 since it is unable to induce anchorage-independent growth of NRK or FR3T3 target cells in the presence or absence of exogenous EGF. Moreover, free functional EGF receptors are available at the HT-29 cell surface.