Kras G12CおよびG12D駆動型肺癌における腫瘍形成能、免疫原性、およびKras阻害後の再発のマウスモデルでの違い

The development of allele-specific KRAS inhibitors underscores the importance of understanding the distinct tumor biology associated with common KRAS mutations, G12D and G12C, in genetically engineered mouse models (GEMMs) of non-small cell lung cancer (NSCLC) and patient samples. Lung tumors driven by the most common KRAS mutation, G12C, show delayed onset and slower progression compared with those driven by KRAS G12D in patients and mice. G12C tumors display lower proliferation and increased immune cell engagement, the latter of which is consistent with observations in patient tumors. Allele-specific KRAS G12C/D inhibitors effectively suppress the growth of respective autochthonous lung tumors. However, G12D-driven tumors relapse more rapidly than G12C-driven tumors in autochthonous models, reflecting greater intrinsic aggressiveness. Given this aggressive clinical behavior, we focused on elucidating the mechanism of action and strategies to potentiate KRAS^G12D inhibition in nonimmunogenic and immunogenic lung cancer models. G12D inhibition enhances tumor antigen presentation, activates T cells, and enables antigen-specific cytotoxicity, leading to efficacy with immune checkpoint blockade combination. This combination induces durable immune memory in immunogenic models but not in nonimmunogenic settings. Our findings underscore key differences between KRAS G12D and G12C mutations in shaping lung cancer biology, reveal distinct resistance dynamics under long-term targeted therapy, and uncover immune-mediated mechanisms specific to KRAS^G12D inhibition with direct clinical and translational relevance.