Figure 6.

Schematic representation of the signaling pathways involved in cell dormancy. (A) Cell signaling pathways activated by low cell density under clonogenic conditions (i. e. in isotonic or slightly hypotonic culture medium). Under these conditions, a mild activation of BMP/TGFβ (Fig. 1A, 5A and Fig. S4C) and redox imbalance (Fig. 1A and 5B) signaling pathways is observed, redox imbalance also contributing to the activation of BMP/TGFβ signaling (Fig. 5B). (B) Reinforcements of these signaling pathways under dormancy-inducing conditions in slightly hypertonic medium. The main effect of hypertonicity is to amplify redox imbalance and BMP/TGFβ signaling (Fig. 3, Fig. 2B and Fig. S4B and C) thus increasing the expression level of the dormancy gene expression signature that is already activated in cells plated at low density but in hypotonic or isotonic medium.