Abstract B131: Quantitative modeling of Syk regulation in B cell chronic lymphocytic leukemia

Abstract

Abstract Spleen tyrosine kinases (Syk) are initiators of B cell receptor-mediated (BCR) signaling events, enabling cells to drive chronic lymphocytic leukemia (CLL) progression. However, the mechanistic principles of biochemical signaling pathways that contribute to CLL pathogenesis are poorly understood. This study investigates Syk-mediated molecular pathways of the BCR signaling network using computational modeling. An expression of ζ chain-associated protein kinase of 70 kD (ZAP-70, Syk-family protein kinase) in the BCR signaling pathway is an adverse prognostic marker in CLL. Therefore, we need a better understanding of molecular mechanisms of Syk family protein kinases and effects of their inhibitors in the BCR signaling pathway. In this work, we dissected several computational models of ZAP-70 and SYK regulation to design an integrated mechanistic description of the BCR signaling pathway, and to explain the observed differences in the clinical behaviors of ZAP-70+ / ZAP-70- phenotypes of CLL patients. Specifically, we characterized the effects of different ZAP-70 and SYK expression and phosphorylation levels on the BCR activation threshold, using stochastic simulations of the BCR signaling network. Preliminary findings suggest that ZAP-70 serves as an adaptor protein that facilitates the recruitment of SYK to the BCR complex. We find that the expression of ZAP-70 enhances the BCR signaling, and therefore correlates with a more aggressive disease course. Our results will help in the development of novel therapies targeting Syk functions to regulate B-CLL responses. Citation Format: Maria P. Frushicheva. Quantitative modeling of Syk regulation in B cell chronic lymphocytic leukemia [abstract]. In: Proceedings of the Second CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; 2016 Sept 25-28; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2016;4(11 Suppl):Abstract nr B131.