Activation of CD8 + T Cells Contributes to Antitumor Effects of CDK4/6 Inhibitors plus MEK Inhibitors

Concurrent MEK and CDK4/6 inhibition shows promise in clinical trials for patients with advanced-stage mutant / solid tumors. The effects of CDK4/6 inhibitor (CDK4/6i) in combination with BRAF/MEK-targeting agents on the tumor immune microenvironment are unclear, especially in melanoma, for which im...

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Veröffentlicht in:Cancer immunology research 2020-09, Vol.8 (9), p.1114-1121
Hauptverfasser: Teh, Jessica L F, Erkes, Dan A, Cheng, Phil F, Tiago, Manoela, Wilski, Nicole A, Field, Conroy O, Chervoneva, Inna, Levesque, Mitch P, Xu, Xiaowei, Dummer, Reinhard, Aplin, Andrew E
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Sprache:eng
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Zusammenfassung:Concurrent MEK and CDK4/6 inhibition shows promise in clinical trials for patients with advanced-stage mutant / solid tumors. The effects of CDK4/6 inhibitor (CDK4/6i) in combination with BRAF/MEK-targeting agents on the tumor immune microenvironment are unclear, especially in melanoma, for which immune checkpoint inhibitors are effective in approximately 50% of patients. Here, we show that patients progressing on CDK4/6i/MEK pathway inhibitor combinations exhibit T-cell exclusion. We found that MEK and CDK4/6 targeting was more effective at delaying regrowth of mutant melanoma in immunocompetent versus immune-deficient mice. Although MEK inhibitor (MEKi) treatment increased tumor immunogenicity and intratumoral recruitment of CD8 T cells, the main effect of CDK4/6i alone and in combination with MEKi was increased expression of CD137L, a T-cell costimulatory molecule on immune cells. Depletion of CD8 T cells or blockade of the CD137 ligand-receptor interaction reduced time to regrowth of melanomas in the context of treatment with CDK4/6i plus MEKi treatment Together, our data outline an antitumor immune-based mechanism and show the efficacy of targeting both the MEK pathway and CDK4/6.
ISSN:2326-6066
2326-6074
DOI:10.1158/2326-6066.CIR-19-0743