The Potential Role of Quorum Sensing in Clonal Growth and Subsequent Expansion of Bone Marrow Stromal Cell Strains in Culture

Figure 4

Clonal expansion depends on serum. (a) Samples of nucleated cells from primary BM-MSC cultures were plated and cultured either in 100 mm dishes at 1.6 cells/cm² density or in 96-well plates at cloning dilution in FBS-supplemented culture medium. Colonies formed in 100 mm dishes (“social” conditions; A, B) could be further expanded. In contrast, colonies grown in 96-well plates at cloning dilution (“isolation” conditions; C, D) could not be further expanded. (b) Proliferation curve of BM-derived clonal cell strain grown in social context (black diagram) or in “isolation” conditions (red diagram). Five individual colonies formed in 96-well plates and 5 from multicolony cultures were tested for PD. (c) Colonies grown in 96-well plates underwent a lower number of PD, 16 (T75 flask), after which the cells became senescent forming colonies identifiable for their unusual, large and irregular shape compared to colonies grown in social context which could be further expanded to 22 PD (T75 flask). Images shown are representative results of secondary cell cultures expanded from colonies formed in social context or grown at cloning dilution. Results are expressed as the (). . Scale bars represent 200 μm as indicated.

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