Cell adhesion induces expression of growth-associated genes in suspension-arrested fibroblasts.
A methylcellulose suspension system that prevents cell-surface contact with the substrate was used to study the role of cell adhesion in the regulation of proliferation. The nonadhesive conditions established by suspension culture cause BALB/c 3T3 (A31) cells to enter a G0 state of growth arrest within 48 hr as defined by an inhibition of DNA synthesis and a suppression of c-myc and histone mRNA expression. The adhesion of these suspension-arrested cells rapidly induces c-fos, c-myc, and actin gene expression. This stimulation did not depend on the presence of serum since the adhesion of suspension-arrested cells, in the absence of serum, also induced the expression of c-fos and c-myc mRNAs. In addition, adhesion onto fibronectin increased the number of cells able to respond to epidermal growth factor and insulin and progress into S phase. These results indicate that adhesion of suspension-arrested cells activates the G0/G1 transition independent of growth factors.
D000199:Actins / Q000235:genetics; D000818:Animals; D002448:Cell Adhesion; D004261:DNA Replication; D005347:Fibroblasts / Q000378:metabolism*; D005353:Fibronectins / Q000378:metabolism; D005786:Gene Expression Regulation; D006133:Growth Substances / Q000235:genetics*; D007328:Insulin / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D009857:Oncogenes; D014158:Transcription, Genetic
D000199:Actins; D005353:Fibronectins; D006133:Growth Substances; D007328:Insulin