MEK Inhibition Remodels the Immune Landscape of Mutant KRAS Tumors to Overcome Resistance to PARP and Immune Checkpoint Inhibitors.

ABSTRACT: Mutant KRAS tumors are associated with poor outcomes, at least in part, due to decreased therapeutic sensitivity. Here, we show that KRAS mutations are associated with resistance to monotherapy and combination therapy with PARP inhibitors (PARPi) and immune checkpoint blockade with anti-PD-L1 antibodies. In mutant KRAS tumors, inhibition of KRAS signaling with MEK inhibitors (MEKi) triggered and amplified PARPi-induced DNA damage, cytosolic double-stranded DNA accumulation, STING pathway activation, and CD8⁺ T-cell recruitment. Moreover, MEKi decreased myeloid-derived suppressor cell infiltration, in part, by inhibiting IL6 and GMCSF production. Importantly, addition of MEKi to PARPi and anti-PD-L1 resulted in marked tumor inhibition in immunocompetent mutan

SUBMITTER: Yang B 

PROVIDER: S-EPMC8265237 | biostudies-literature | 2021 May

REPOSITORIES: biostudies-literature