Lyn Phosphorylates and Controls ROR1 Surface Dynamics During Chemotaxis of CLL Cells.

Zankruti Dave,Martin Běhal,Vítězslav Bryja,Štěpán Čada,Kateřina Hanáková,Jana Kotašková,Nikodém Zezula,Michal Šmída,Šárka Pavlová,Sri Ranjani Ganji,Šárka Pospíšilová,Pavlína Janovská,Zbyněk Zdráhal,Pavel Krejci,Kristína Gömöryová,Helena Peschelová,Olga Vondálová Blanářová

doi:10.3389/fcell.2022.838871

Abstract

Chronic lymphocytic leukemia (CLL) and mantle cell lymphoma (MCL) are malignancies characterized by the dependence on B-cell receptor (BCR) signaling and by the high expression of ROR1, the cell surface receptor for Wnt-5a. Both, BCR and ROR1 are therapeutic targets in these diseases and the understanding of their mutual cross talk is thus of direct therapeutic relevance. In this study we analyzed the role of Lyn, a kinase from the Src family participating in BCR signaling, as a mediator of the BCR-ROR1 crosstalk. We confirm the functional interaction between Lyn and ROR1 and demonstrate that Lyn kinase efficiently phosphorylates ROR1 in its kinase domain and aids the recruitment of the E3 ligase c-CBL. We show that ROR1 surface dynamics in migrating primary CLL cells as well as chemotactic properties of CLL cells were inhibited by Lyn inhibitor dasatinib. Our data establish Lyn-mediated phosphorylation of ROR1 as a point of crosstalk between BCR and ROR1 signaling pathways.

Highlights

The ROR protein family comprises of ROR1 and ROR2, which are both type 1 transmembrane receptors
Our study is the first to show that the Src family kinase Lyn, an important component of B-cell receptor (BCR) signaling, phosphorylates ROR1 intracellularly and controls its surface levels
The phosphorylation of ROR1 by Lyn identifies a novel crosstalk between ROR1 and BCR signaling. This crosstalk can be of particular importance in chronic lymphocytic leukemia (CLL) and mantle cell lymphoma (MCL) where both, ROR1 and BCR pathways, represent therapeutic targets

Summary

Introduction

The ROR (receptor tyrosine kinase like orphan receptor) protein family comprises of ROR1 and ROR2, which are both type 1 transmembrane receptors. ROR proteins were referred to as orphan receptors on account of the lack of identity of their ligands. Wnt-5a/ROR pathway is an essential signaling pathway that controls cell polarity and migration during embryonic development and tissue homeostasis (Oishi et al, 2003; He et al, 2008). CLL is a form of hematologic cancer which is manifested as a steady accumulation of mature CD5+ B-cells in the bone marrow, lymphoid tissues and peripheral blood. It is the most common form of adult leukemia in the western hemisphere, with an incidence of 5 per 100,000 each year and an average median age of onset around 70 years. Part of the CLL cases progress rapidly, require treatment and their overall life expectancy is decreased (Hallek, 2019)

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