Precursor B-ALL Cell Lines Differentially Respond to SYK Inhibition by Entospletinib.

Sina Sender,Anett Sekora,Christian Junghanss,Oleksandra Chabanovska,Annegret Becker,Simon Villa Perez,Hugo Murua Escobar,Anaclet Ngezahayo

doi:10.3390/ijms22020592

Abstract

Background: Impaired B-cell receptor (BCR) function has been associated with the progress of several B-cell malignancies. The spleen tyrosine kinase (SYK) represents a potential therapeutic target in a subset of B-cell neoplasias. In precursor B-acute lymphoblastic leukemia (B-ALL), the pathogenic role and therapeutic potential of SYK is still controversially discussed. We evaluate the application of the SYK inhibitor entospletinib (Ento) in pre- and pro-B-ALL cell lines, characterizing the biologic and molecular effects. Methods: SYK expression was characterized in pre-B-ALL (NALM-6) and pro-B-ALL cell lines (SEM and RS4;11). The cell lines were exposed to different Ento concentrations and the cell biological response analyzed by proliferation, metabolic activity, apoptosis induction, cell-cycle distribution and morphology. BCR pathway gene expression and protein modulations were further characterized. Results: Ento significantly induced anti-proliferative and pro-apoptotic effects in NALM-6 and SEM, while barely affecting RS4;11. Targeted RNAseq revealed pronounced gene expression modulation only in NALM-6, while Western Blot analyses demonstrated that vital downstream effector proteins, such as pAKT, pERK, pGSK3β, p53 and BCL-6, were affected by Ento exposure in the inhibitor-sensitive cell lines. Conclusion: Different acting modes of Ento, independent of pre-BCR dependency, were characterized, unexpected in SEM. Accordingly, SYK classifies as a potential target structure in a subset of pro-B-ALLs.

Highlights

B-cell receptor (BCR) signaling, as an essential regulating network, provides the main signals for survival and proliferation in hematopoietic cells [1]
We provide an in vitro-based study, which aimed to illustrate the application of entospletinib as a specific spleen tyrosine kinase (SYK) inhibitor on pre- and pro-B-acute lymphoblastic leukemia cell lines, in order to further demonstrate a possible application in a subset of precursor B-ALL and, to elucidate the underlying diverging acting modes
Pro-B-ALL Cell Line SEM is Characterized by High SYK and pSYK Expression

Summary

Introduction

B-cell receptor (BCR) signaling, as an essential regulating network, provides the main signals for survival and proliferation in hematopoietic cells [1]. SYK fulfills certain functions independent of BCR signaling, e.g., signal transduction from tumor necrosis factor (TNF) superfamily receptors, integrins and cytokines [2] Activation of these pathways leads to proliferation, differentiation, cytoskeletal remodeling, cytokine release and survival [2]. The spleen tyrosine kinase (SYK) represents a potential therapeutic target in a subset of B-cell neoplasias. We evaluate the application of the SYK inhibitor entospletinib (Ento) in pre- and pro-B-ALL cell lines, characterizing the biologic and molecular effects. Methods: SYK expression was characterized in pre-B-ALL (NALM-6) and pro-B-ALL cell lines (SEM and RS4;11). Targeted RNAseq revealed pronounced gene expression modulation only in NALM-6, while Western Blot analyses demonstrated that vital downstream effector proteins, such as pAKT, pERK, pGSK3β, p53 and BCL-6, were affected by Ento exposure in the inhibitor-sensitive cell lines. SYK classifies as a potential target structure in a subset of pro-B-ALLs

Methods

Results

Discussion

Conclusion