Abstract LB266: AMG510-mediated inactivation of BCL-xL protein promotes Gasdermin-E-dependent pyroptosis in KRAS-G12C mutant non-small cell lung cancer
Authors: Luo Linfeng , Li Anlin , Du Wei , Chen Maojian , Li JIng , Zhou Yixin , Zhang Li , Hong Shaodong 
Published: April 2024

Introduction: Studies have shown that molecular targeted therapy can mediate Gasdermin-E (GSDME) dependent pyroptosis. However, GSDME expression is suppressed in many mutated patients, including those with KRAS-G12C-mutated non-small-cell lung cancer (NSCLC). The efficacy of AMG510 against KRAS-G12C inhibition (KRAS-G12Ci) is constrained by tumor recurrence. Pyroptosis is widely involved in the occurrence and development of tumors. However, the role and molecular mechanism of AMG510 in pyroptosis have not been well identified. Here, we demonstrate that inactivation of anti-apoptotic Bcl-2 family members during KRAS-G12Ci treatment enhances pyroptosis, which then promotes the sensitivity of AMG510 in NSCLC.

Methods: We assessed pyroptosis using live cells imaging, LDH release assays, ELISA, Western blotting, and flow cytometry. In vitro assays were used to investigate the function of GSDME. Co-culture between peripheral blood mononuclear cells (PBMCs) and KRAS-G12C mutant lung cancer cell lines explored the anti-tumor immunity of cytotoxic T lymphocytes affected by knockdown of GSDME. The molecular mechanism was determined using bulk RNA sequencing, molecular cloning technology, and Western blotting.

Results: We demonstrated that KRAS G12Ci treatment promotes cleavage of GSDME, release of high mobility group protein B1 (HMGB1), and LDH, markers of pyroptotic cell death. Additionally, GSDME was significantly downregulated in KRAS-mutated NSCLC compared with patients of KRAS wild type in TCGA cohort, while significantly upregulated after AMG510 treatment and downregulated after AMG510 resistance in vitro assay. We identified that KRAS-G12Ci resulted in the inactivation of BCL-xL, leading to caspase-3-dependent cleavage of gasdermin E. Conversely, amplification of BCL-xL downregulated the expression of GSDME, therefore suppressing the process of pyroptosis. GSDME knockdown in KRAS-G12C mutant lung cancer cell lines showed defective HMGB1 release, reduced caspase-3 viability, and decreased granzyme B and IFN-γ secretion by CD8+ T cells in response to KRAS-G12Ci, and more frequent tumor cell growth.

Conclusion: Our findings indicate that GSDME-dependent pyroptosis is a critical determinant of KRAS-G12C-targeted inhibitor AMG510, and through the modulation exerted by the Bcl-2 family protein BCL-xL upon GSDME. These findings suggest that activation of GSDME may provide an effective strategy to sensitize cancer cells to KRAS-G12Ci treatment.

Citation Format: Linfeng Luo, Anlin Li, Wei Du, Maojian Chen, JIng Li, Yixin Zhou, Li Zhang, Shaodong Hong. AMG510-mediated inactivation of BCL-xL protein promotes Gasdermin-E-dependent pyroptosis in KRAS-G12C mutant non-small cell lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB266.