Density-dependent inhibition of growth: Inhibitorydiffusible factors from 3T3- and rous sarcoma virus (RSV)-transformed 3T3 cells

✍ Scribed by Louise Harel; Gilles Chatelain; Alice Golde

• Publisher: John Wiley and Sons
• Year: 1984
• Tongue: English
• Weight: 497 KB
• Volume: 119
• Category: Article
• ISSN: 0021-9541
• DOI: 10.1002/jcp.1041190117

✦ Synopsis

We recently fractionated, from the culture medium of 3T3 cells, a therrnolabile inhibitory diffusible factor (IDFN) with a molecular weight of about 40,000 daltons, which decreased nucleic acids synthesis of stimulated target 3T3 cells. In the present publication the inhibitory activities of IDFN (produced by 3T3 cells) and IDFT (produced by RSV-transformed 3T3 [3T3 SRA/H] cells) on 3T3 and 3T3 SRAlH cells have been compared. The inhibitory activity of IDFN decreased (by a mean of 57%) when it was tested on transformed instead of 3T3 cells. On the other hand, lDFT was able to decrease I4C-inosine incorporation in target 3T3 cells. However, the inhibitory activity of IDFT decreased (by mean 50%) when tested on 3T3 SRA/H instead of 373 cells. Therefore, transformed cells produced an inhibitory factor but were less sensitive than 3T3 cells to its inhibitory activity. The inhibitory activity of IDF-r on 3T3 SRA/H cells was only 20% of the inhibitory activity of I D F N on 3T3 cells. This appreciable difference is of particular interest, since it could explain the release of density-dependent inhibition of growth (DDI) in transformed 3T3 SRA/H cells. Furthermore, it provides more evidence for the hypothesis that, in 3T3 cells, DDI of growth is due to the release of an inhibitory molecule into the medium, and that I D F N is in fact, the inhibitory molecule involved in this phenomenon.