Modulation of Akt vs Stat3 activity by the focal adhesion kinase in non-neoplastic mouse fibroblasts
- Department of Biomedical and Molecular Sciences and Department of Pathology and Molecular Medicine, Queen's University, Kingston, Ontario, K7L 3N6 (Canada)
- Department of Chemical and Physical Sciences (CPS), University of Toronto Mississauga, 3359 Mississauga Rd, Mississauga, ON, L5L 1C6 (Canada)
- Department of Chemical and Physical Sciences, University of Toronto, Mississauga, Ontario, L5L 1C6 (Canada)
Adhesion of cells to each other and to the extracellular matrix (ECM) are both required for cellular functions. Cell-to-cell adhesion is mediated by cadherins and their engagement triggers the activation of Stat3, which offers a potent survival signal. Adhesion to the ECM on the other hand, activates FAK which attracts and activates Src, as well as receptor tyrosine kinases (RTKs), the PI3k/Akt and Ras/Erk pathways. However, the effect of cell density upon FAK and Akt activity has not been examined. We now demonstrate that, interestingly, despite being potent Stat3 activators, Src and RTKs are unable to activate Stat3 in sparsely growing (i.e., without cadherin engagement), non-neoplastic cells attached to the ECM. In contrast, cell aggregation (i.e., cadherin engagement in the absence of adhesion to a solid substratum) was found to activate both Stat3 and Akt. Pharmacologic or genetic reduction of FAK activity abolished Akt activity at low densities, indicating that FAK is an important activator of Akt in this setting. Notably, FAK knockout increased cellular sensitivity to the Stat3 inhibitor CPA7, while FAK reintroduction restored resistance to this drug. These findings suggest a complementary role of integrin/FAK/Akt and cadherin/Stat3-mediated pro-survival pathways, which may be of significance during neoplastic transformation and metastasis.
- OSTI ID:
- 23195617
- Journal Information:
- Experimental Cell Research, Vol. 404, Issue 1; Other Information: Copyright (c) 2021 Elsevier Inc. All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 0014-4827
- Country of Publication:
- United States
- Language:
- English
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