Dual PI3K/ERK inhibition induces necroptotic cell death of Hodgkin Lymphoma cells through IER3 downregulation.

Silvia Laura Locatelli,Giuliano Giuseppe Stirparo,Giuseppa Careddu,Carmelo Carlo-Stella,Luca Castagna,Armando Santoro

doi:10.1038/srep35745

Silvia Laura Locatelli, Giuliano Giuseppe Stirparo + Show 4 more

Open Access

https://doi.org/10.1038/srep35745

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Journal: Scientific Reports	Publication Date: Oct 21, 2016
Citations: 19	License type: CC BY 4.0

Affiliation: Humanitas University, University of Milan

Abstract

PI3K/AKT and RAF/MEK/ERK pathways are constitutively activated in Hodgkin lymphoma (HL) patients, thus representing attractive therapeutic targets. Here we report that the PI3K/ERK dual inhibitor AEZS-136 induced significant cell proliferation inhibition in L-540, SUP-HD1, KM-H2 and L-428 HL cell lines, but a significant increase in necroptotic cell death was observed only in two out of four cell lines (L-540 and SUP-HD1). In these cells, AEZS-136-induced necroptosis was associated with mitochondrial dysfunction and reactive oxygen species (ROS) production. JNK was activated by AEZS-136, and AEZS-136-induced necroptosis was blocked by the necroptosis inhibitor necrostatin-1 or the JNK inhibitor SP600125, suggesting that JNK activation is required to trigger necroptosis following dual PI3K/ERK inhibition. Gene expression analysis indicated that the effects of AEZS-136 were associated with the modulation of cell cycle and cell death pathways. In the cell death-resistant cell lines, AEZS-136 induced the expression of immediate early response 3 (IER3) both in vitro and in vivo. Silencing of IER3 restored sensitivity to AEZS-136-induced necroptosis. Furthermore, xenograft studies demonstrated a 70% inhibition of tumor growth and a 10-fold increase in tumor necrosis in AEZS-136-treated animals. Together, these data suggest that dual PI3K/ERK inhibition might be an effective approach for improving therapeutic outcomes in HL.

Highlights

9,300 new cases of Hodgkin lymphoma (HL) and 1,200 resulting deaths are estimated to occur each year in the United States[1]
Since the phosphatidylinositol 3-kinase (PI3K)/Akt and Raf/MEK/ERK pathways regulate members of the Bcl-2 family of proteins, such as Mcl-125, we examined whether AEZS-136 would affect Mcl-1 expression
Genetic and pharmacological analyses have shown that the RAS/RAF1/MEK1/MEK2 arm of the MAPK signaling pathway is responsible for ERK/AKT signaling downstream of S6K1/PI3K when mTORC1 activity is lost, indicating that targeting the MAPK pathway might improve the efficacy of mTORC1 inhibition[36]

Summary

Introduction

9,300 new cases of Hodgkin lymphoma (HL) and 1,200 resulting deaths are estimated to occur each year in the United States[1]. The alkylating agent bendamustine[10], the anti-CD30 antibody-drug conjugate brentuximab vedotin[11,12], and the anti-programmed cell death protein-1 (PD-1) antibody nivolumab[13,14] have demonstrated extraordinary efficacy. Limited evidence has been provided for long-term disease control using these agents, suggesting that either combination therapy or a single agent with multitargeting capacity is required[15]. To investigate the therapeutic potential of PI3K and ERK dual inhibition, we used AEZS-136 [kindly provided by Æterna Zentaris (Frankfurt, Germany, EU)] in preclinical models of HL. The anti-proliferative efficacy of AEZS-136 was evaluated in more than 40 human tumor cell lines and physio-chemical as well as in-vitro ADMET properties were widely assessed. Aeterna Zentaris, personal communication)[24]

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