MEK inhibition overcomes chemoimmunotherapy resistance by inducing CXCL10 in cancer cells
Menée à l'aide de modèles murins de cancer du poumon ainsi que de données du projet "The Cancer Genome Atlas" puis menée à l'aide de 4 cohortes incluant au total 238 patients atteints d'un cancer du poumon non à petites cellules de stade avancé, cette étude met en évidence un mécanisme par lequel l'inhibition de MEK lève la résistance tumorale à une chimio-immunothérapie (pémétrexed/cisplatine et inhibiteur de point de contrôle immunitaire) en induisant la sécrétion du ligand CXCL10 par les cellules cancéreuses
Chemotherapy with anti PD-1/PD-L1 antibodies has become the standard of care for patients with metastatic non-small cell lung cancer (mNSCLC). Using lung tumor models, where pemetrexed and cisplatin (PEM/CDDP) chemotherapy remains unable to synergize with immune checkpoint inhibitors (ICIs), we linked the failure of this treatment with its inability to induce CXCL10 expression and CD8+ T cell recruitment. Using drug screening, we showed that combining a MEK inhibitor (MEKi) with PEM/CDDP triggers CXCL10 secretion by cancer cells and CD8+ T cell recruitment, sensitizing it to ICIs. PEM/CDDP plus a MEKi promotes optineurin (OPTN)-dependent mitophagy, resulting in CXCL10 production in a mitochondrial DNA- and TLR9-dependent manner. TLR9 or autophagy/mitophagy inhibition abolishes the anti-tumor efficacy of PEM/CDDP plus MEKi/anti-PD-L1 therapy. In human NSCLCs, high OPTN, TLR9, and CXCL10 expression is associated with a better response to ICIs. Our results underline the role of TLR9- and OPTN-dependent mitophagy in enhancing chemoimmunotherapy efficacy.