High Levels of miR-7-5p Potentiate Crizotinib-Induced Cytokilling and Autophagic Flux by Targeting RAF1 in NPM-ALK Positive Lymphoma Cells.

Domenico Sorrentino,Manon Farcé,Julie Frentzel,Stéphane Manenti,Rafael B Blasco,Sylvie Giuriato,Fabienne Meggetto,Avédis Torossian,Estelle Espinos,Chiara Pighi,Coralie Hoareau-Aveilla,Géraldine Mitou,Roberto Chiarle

doi:10.3390/cancers12102951

Abstract

Simple SummaryAnaplastic lymphoma kinase positive anaplastic large cell lymphomas are a pediatric disease, which still needs treatment improvement. Crizotinib was the first ALK-targeted inhibitor used in clinics, but relapses are now known to occur. Current research efforts indicate that combined therapies could represent a superior strategy to eradicate malignant cells and prevent tumor recurrence. Autophagy is a self-digestion cellular process, known to be induced upon diverse cancer therapies. Our present work demonstrates that the potentiation of the crizotinib-induced autophagy flux, through the serine/threonine kinase RAF1 downregulation, drives ALK+ ALCL cells to death. These results should encourage further investigations on the therapeutic modulation of autophagy in this particular cancer settings and other ALK-related malignancies.Anaplastic lymphoma kinase positive anaplastic large cell lymphomas (ALK+ ALCL) are an aggressive pediatric disease. The therapeutic options comprise chemotherapy, which is efficient in approximately 70% of patients, and targeted therapies, such as crizotinib (an ALK tyrosine kinase inhibitor (TKI)), used in refractory/relapsed cases. Research efforts have also converged toward the development of combined therapies to improve treatment. In this context, we studied whether autophagy could be modulated to improve crizotinib therapy. Autophagy is a vesicular recycling pathway, known to be associated with either cell survival or cell death depending on the cancer and therapy. We previously demonstrated that crizotinib induced cytoprotective autophagy in ALK+ lymphoma cells and that its further intensification was associated with cell death. In line with these results, we show here that combined ALK and Rapidly Accelerated Fibrosarcoma 1 (RAF1) inhibition, using pharmacological (vemurafenib) or molecular (small interfering RNA targeting RAF1 (siRAF1) or microRNA-7-5p (miR-7-5p) mimics) strategies, also triggered autophagy and potentiated the toxicity of TKI. Mechanistically, we found that this combined therapy resulted in the decrease of the inhibitory phosphorylation on Unc-51-like kinase-1 (ULK1) (a key protein in autophagy initiation), which may account for the enforced autophagy and cytokilling effect. Altogether, our results support the development of ALK and RAF1 combined inhibition as a new therapeutic approach in ALK+ ALCL.

Highlights

Anaplastic lymphoma kinase positive anaplastic large cell lymphomas (ALK+ ALCL) are a distinct clinicopathologic non-Hodgkin’s lymphoma, primarily occurring in children and young adults [1]
Our present study demonstrates that miRNA-7, known primarily to harbor tumor suppressive functions in diverse cancer types [40], and Rapidly Accelerated Fibrosarcoma 1 (RAF1), one of its targets [41,42,43,44], play essential roles in Nucleophosmin-Anaplastic Lymphoma Kinase (NPM-ALK)+ ALCL, by controlling the autophagy flux and tumor cell fate
We focused our interest on the miRNA hsa-miR-7-5p, which appeared to be the most significantly downregulated miRNA upon NPM-ALK inactivation (Figure 1A and Table 1)

Summary

Introduction

Anaplastic lymphoma kinase positive anaplastic large cell lymphomas (ALK+ ALCL) are a distinct clinicopathologic non-Hodgkin’s lymphoma, primarily occurring in children and young adults [1]. The current treatment of this lymphoma is essentially based on aggressive chemotherapy, which is not optimal as 30% of the patients relapse 5 years post-treatment, regardless of the drug cocktail used or the treatment duration [5,6] This observation led to the development of therapies directly targeting the NPM-ALK oncoprotein. The success of this TKI was hampered by the occurrence of resistance to the drug [9,10] This motivated both the generation of a new generation of TKI inhibitors [11,12] as well as the development of diverse combined therapies [13,14] in an attempt to prevent relapses and to eradicate the malignant cells. Our work focused for the last few years on studying the possible therapeutic modulations of macro-autophagy to improve crizotinib therapy [15,16,17]

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