Regan2022 - Mechanosensitive EMT model with autocrine TGFbeta signaling

This model is an expansion of the Regan2022 - Mechanosensitive EMT model (MODEL2208050001); it includes a TGFβ signaling module and autocrine signaling in mesenchymal cells. The expanded 150-node (630 link) modular model undergoes EMT triggered by biomechanical and growth signaling crosstalk, or by TGFβ. As its predecessor, this model also reproduces the ability of the core EMT transcriptional network to maintain distinct epithelial, hybrid E/M and mesenchymal states, as well as EMT driven by mitogens such as EGF on stiff ECM. We also reproduce the observed lack of stepwise MET, in that our model's dynamics does not pass through the hybrid E/M state during MET. We show that in the absence of strong autocrine signals such as TGFβ (not included in this version), cells cannot maintain their mesenchymal state in the absence of mitogens, on softer matrices, or at high cell density. In contrast, potent autocrine signaling can stabilize the mesenchymal state in all but very dense monolayers on soft ECM. This expanded model also reproduces the inhibitory effects of TGFβ on proliferation and anoikis resistance in mesenchymal cells, as well as its ability to trigger apoptosis on soft ECM vs. EMT on stiff matrices. The model offers several experimentally testable predictions related to the effect of neighbors on partial vs. full EMT, the tug of war between mitosis and the maintenance of migratory hybrid E/M states, as well as cell cycle defects in dynamic, heterogeneous populations of epithelial, hybrid E/M and mesenchymal cells.