Harmine, a dual-specificity tyrosine phosphorylation-regulated kinase (DYRK) inhibitor induces caspase-mediated apoptosis in neuroblastoma

Katie L Uhl,Chad R Schultz,Dirk Geerts,André S Bachmann

doi:10.1186/s12935-018-0574-3

Abstract

BackgroundNeuroblastoma (NB) is an early childhood malignancy that arises from the developing sympathetic nervous system. Harmine is a tricyclic β-carboline alkaloid isolated from the harmal plant that exhibits both cytostatic and cytotoxic effects. Harmine is capable of blocking the activities of dual-specificity tyrosine phosphorylation-regulated kinase (DYRK) family proteins and mitogen-activated protein kinase. These kinases promote proliferation and inhibit apoptosis.MethodsFour human NB cell lines were used to study the effects of harmine treatment: SKNBE and KELLY (MYCN-amplified) as well as SKNAS and SKNFI (MYCN non-amplified). The anti-cancer properties of harmine were examined by RealTime-Glo MT cell viability assays, caspase activity assays, PARP cleavage using Western blot analysis, and flow cytometry-based Annexin V detection. A molecular interaction model of harmine bound to the DYRK2 family kinase was generated by computational docking using X-ray structures. NB tumors from human patients were profiled for DYRK mRNA expression patterns and clinical correlations using the R2 platform.ResultsThe IC50 values for harmine after 72 h treatment were 169.6, 170.8, and 791.7 μM for SKNBE, KELLY, and SKNFI, respectively. Exposure of these NB cell lines to 100 μM of harmine resulted in caspase-3/7 and caspase-9 activation as well as caspase-mediated PARP cleavage and Annexin V-positive stained cells, as early as 24 h after treatment, clearly suggesting apoptosis induction, especially in MYCN-amplified cell lines. Elevated DYRK2 mRNA levels correlated with poor prognosis in a large cohort of NB tumors.ConclusionHarmine is a known inhibitor of DYRK family kinases. It can induce apoptosis in NB cell lines, which led us to investigate the clinical correlations of DYRK family gene expression in NB tumors. The patient results support our hypothesis that DYRK inhibition by harmine and the subsequent triggering of caspase-mediated apoptosis might present a novel approach to NB therapy.

Highlights

Neuroblastoma (NB) is an early childhood malignancy that arises from the developing sympathetic nervous system
We identified that harmine induces apoptotic cell death in NB cells, generated a molecular interaction model for harmine bound to DYRK2, and showed that DYRK2 mRNA expression patterns in a large cohort of human NB tumors suggest the involvement of DYRK2 in NB tumorigenesis
Harmine induces dose‐ and time‐dependent NB cell death To study the effect of harmine on the morphology of NB cells, four NB cell lines were exposed to 100 μM harmine

Summary

Introduction

Neuroblastoma (NB) is an early childhood malignancy that arises from the developing sympathetic nervous system. Harmine is a tricyclic β-carboline alkaloid isolated from the harmal plant that exhibits both cytostatic and cytotoxic effects. Harmine is capable of blocking the activities of dual-specificity tyrosine phosphorylation-regulated kinase (DYRK) family proteins and mitogen-activated protein kinase. These kinases promote proliferation and inhibit apoptosis. Neuroblastoma (NB) is an early childhood malignancy that arises from the developing sympathetic nervous system, resulting in aggressive tumor formation in. Harmine is a tricyclic β-carboline alkaloid isolated from harmal seeds and acts as a monoamine oxidase A (MAO-A) inhibitor [3,4,5]. Intake of alkaloids from the harmal plant can have anti-depressive, analgesic, and anti-bacterial pharmacological effects [6,7,8]. While lower concentrations of harmine typically induced cytostasis, higher concentrations are associated with cytotoxicity [10]

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