Three-dimensional growth of glial cell lines affects growth factor and growth factor receptor mRNA levels.

We have studied, at the mRNA level, the influence of various defined growth conditions on the expression of TGF-alpha, PDGF-BB, EGF-R, PDGF-R alpha, and PDGF-R beta in five different glioma cell lines (D-37MG, D-54MG, D-263MG, GaMG, and U-251MG). RNA isolated from logarithmically growing, confluent monolayer cells or multicellular spheroids was analyzed. Northern blot experiments show that with a few exceptions, specific mRNA steady-state levels were considerably higher in cells grown in a three-dimensional organization relative to cells in the logarithmic growth phase.