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Spleen Tyrosine Kinase-Mediated Autophagy Is Required for Epithelial-Mesenchymal Plasticity and Metastasis in Breast Cancer

Shinde, Aparna and Hardy, Shana D and Kim, Dongwook and Akhand, Saeed Salehin and Jolly, Mohit Kumar and Wang, Wen-Hung and Anderson, Joshua C and Khodadadi, Ryan B and Brown, Wells S and George, Jason T and Liu, Sheng and Wan, Jun and Levine, Herbert and Willey, Christopher D and Krusemark, Casey J and Geahlen, Robert L and Wendt, Michael K (2019) Spleen Tyrosine Kinase-Mediated Autophagy Is Required for Epithelial-Mesenchymal Plasticity and Metastasis in Breast Cancer. In: CANCER RESEARCH, 79 (8). pp. 1831-1843.

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Official URL: https://dx.doi.org/10.1158/0008-5472.CAN-18-2636

Abstract

The ability of breast cancer cells to transiently transition between epithelial and mesenchymal states contributes to their metastatic potential. Therefore, driving tumor cells into a stable mesenchymal state, as opposed to complete tumor cell eradication, presents an opportunity to pharmacologically limit disease progression by promoting an asymptomatic state of dormancy. Here, we compare a reversible model of epithelial-mesenchymal transition (EMT) induced by TGF beta to a stable mesenchymal phenotype induced by chronic exposure to the ErbB kinase inhibitor lapatinib. Only cells capable of returning to an epithelial phenotype resulted in skeletal metastasis. Gene expression analyses of the two mesenchymal states indicated similar transition expression profiles. A potently downregulated gene in both datasets was spleen tyrosine kinase (SYK). In contrast to this similar diminution in mRNA, kinome analyses using a peptide array and DNA-conjugated peptide substrates showed a robust increase in SYK activity upon TGF beta-induced EMT only. SYK was present in cytoplasmic RNA processing depots known as P-bodies formed during the onset of EMT, and SYK activity was required for autophagy-mediated clearance of P-bodies during mesenchymal-epithelial transition (MET). Genetic knockout of autophagy-related 7 (ATG7) or pharmacologic inhibition of SYK activity with fostamatinib, a clinically approved inhibitor of SYK, prevented P-body clearance and MET, inhibiting metastatic tumor outgrowth. Overall, this study suggests assessment of SYK activity as a biomarker for metastatic disease and the use of fostamatinib as a means to stabilize the latency of disseminated tumor cells.

Item Type: Journal Article
Additional Information: copyright for this article belongs to AMER ASSOC CANCER RESEARCH
Department/Centre: Division of Interdisciplinary Research > Centre for Biosystems Science and Engineering
Depositing User: Ms R.S. Ranganayaki
Date Deposited: 27 May 2019 07:37
Last Modified: 27 May 2019 07:37
URI: http://eprints.iisc.ac.in/id/eprint/62592

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