The pharmalogical reactivation of p53 function improves breast tumor cell lysis by granzyme B and NK cells through induction of autophagy

Marie Chollat-Namy,Djazia Haferssas,Salem Chouaib,Thouraya Ben Safta-Saadoun,Guillaume Meurice,Jerome Thiery

doi:10.1038/s41419-019-1950-1

Abstract

Cytotoxic T lymphocytes (CTL) and natural killer cells (NK)-mediated elimination of tumor cells is mostly dependent on Granzyme B apoptotic pathway, which is regulated by the wild type (wt) p53 protein. Because TP53 inactivating mutations, frequently found in human tumors, could interfere with Granzyme B-mediated cell death, the use of small molecules developed to reactivate wtp53 function in p53-mutated tumor cells could optimize their lysis by CTL or NK cells. Here, we show that the pharmalogical reactivation of a wt-like p53 function in p53-mutated breast cancer cells using the small molecule CP-31398 increases their sensitivity to NK-mediated lysis. This potentiation is dependent on p53-mediated induction of autophagy via the sestrin-AMPK-mTOR pathway and the ULK axis. This CP31398-induced autophagy sequestrates in autophagosomes several anti-apoptotic proteins, including Bcl-XL and XIAP, facilitating Granzyme B-mediated mitochondrial outer membrane permeabilization, caspase-3 activation and Granzyme B- or NK cell-induced apoptosis. Together, our results define a new way to increase cytotoxic lymphocyte-mediated lysis of p53-mutated breast cancer cell, through a p53-dependent autophagy induction, with potential applications in combined immunotherapeutic approaches.

Highlights

Introduction CytotoxicT lymphocytes (CTL) and natural killer (NK)are important effector cells involved in the elimination of tumor cells, principally by releasing the contents of cytotoxic granules into the immune synapse[1]
Granzyme A (GzmA)induced cell death, which rely on reactive oxygen species (ROS) and on the SET complex, but is caspases, Bax/Bak, Bcl-2/Bcl-XL and cytochrome c independent[46,47,48,49], was not increased following CP-31398 treatment (Fig. 8g). These results indicate that the sequestration in CP-31398induced autophagosomes of several anti-apoptotic proteins, including Bcl-XL and XIAP, which normally prevent Granzyme B (GzmB)-induced mitochondrial outer membrane permeabilization (MOMP) and effector caspases cleavage, potentiates GzmB- and NK-dependent apoptosis of p53mutated cells, without the need of degradation in autophagosomes
Here, we demonstrated that the pharmalogical reactivation of a wt-like p53 transcriptional function in p53mutated breast cancer cells using the small molecule CP31398 increases their susceptibility to NK cell-mediated lysis by an autophagy-dependent mechanism

Summary

Introduction

Are important effector cells involved in the elimination of tumor cells, principally by releasing the contents of cytotoxic granules into the immune synapse[1]. The granule mediators of target cell lysis belong to the granzymes (Gzms) family, which induce cell death[2] after their delivery into target cells by the pore-forming protein perforin (PFN)[3]. Human Granzyme B (GzmB), one of the principal mediators of this pathway, preferentially induces target apoptosis in a mitochondria-dependent manner. The wild type (wt) p53 tumor suppressor normally protects cells from a variety of stress and the physiologic consequence of its activation essentially leads to growth arrest or apoptosis[10,11,12], which are important in order to maintain genome integrity[13]. Wtp[53] activation can positively or negatively regulate autophagy[14,15], which is an intracellular self-digestive

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