Protein tyrosine phosphatase PTPN1 modulates cell growth and associates with poor outcome in human neuroblastoma

Caroline E Nunes-Xavier,Laura Zaldumbide,José I López,Rafael Pulido,Ricardo López-Almaraz,Jesús M Cortés,Asier Erramuzpe,Olaia Aurtenetxe

doi:10.1186/s13000-019-0919-9

Abstract

BackgroundProtein tyrosine phosphatases (PTPs) regulate neuronal differentiation and survival, but their expression patterns and functions in human neuroblastoma (NB) are scarcely known. Here, we have investigated the function and expression of the non-receptor PTPN1 on human NB cell lines and human NB tumor samples.Material/methodsNB tumor samples from 44 patients were analysed by immunohistochemistry using specific antibodies against PTPN1, PTPRH, PTPRZ1, and PTEN. PTPN1 knock-down, cell proliferation and tyrosine phosphorylation analyses, and RT-qPCR mRNA expression was assessed on SH-SY5Y, SMS-KCNR, and IMR-32 human NB cell lines.ResultsKnock-down of PTPN1 in SH-SY5Y NB cells resulted in increased tyrosine phosphorylation and cell proliferation. Retinoic acid-mediated differentiation of NB cell lines did not affect PTPN1 mRNA expression, as compared with other PTPs. Importantly, PTPN1 displayed high expression on NB tumors in association with metastasis and poor prognosis.ConclusionsOur results identify PTPN1 as a candidate regulator of NB cell growth and a potential NB prognostic biomarker.

Highlights

Protein tyrosine phosphatases (PTPs) regulate neuronal differentiation and survival, but their expression patterns and functions in human neuroblastoma (NB) are scarcely known
Knock-down of PTPN1 in SH-SY5Y NB cells resulted in increased tyrosine phosphorylation and cell proliferation
PTPN1 knock-down and growth of NB cells To investigate the impact of the expression of PTPN1 in the modulation of growth of human NB cells, SH-SY5Y cells were transiently transfected with specific siRNAs targeting PTPN1 for down-regulation (Fig. 1a), and phosphotyrosine content and MTS cell proliferation assays were performed 72 h after transfection

Summary

Introduction

Protein tyrosine phosphatases (PTPs) regulate neuronal differentiation and survival, but their expression patterns and functions in human neuroblastoma (NB) are scarcely known. We have investigated the function and expression of the non-receptor PTPN1 on human NB cell lines and human NB tumor samples. PTPN1 knock-down, cell proliferation and tyrosine phosphorylation analyses, and RT-qPCR mRNA expression was assessed on SH-SY5Y, SMS-KCNR, and IMR-32 human NB cell lines. The receptor tyrosine kinase (RTK) ALK is mutated in NB tumors and in the germline of patients with familial NB [14,15,16], and ALK plays a major role in the signal transduction mechanism driving NB development, being a major potential target in NB targeted therapy [17, 18]. ALK hyperactivation associates in NB with MYCN gene amplification, the major biomarker for high-risk NB, and

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Conclusion