Venetoclax synergizes with Wnt/β-catenin inhibitor C-82 in acute myeloid leukemia by increasing the degradation of Mcl-1 protein.

BACKGROUND: Due to compensatory survival signalling and overexpression of anti-apoptotic Bcl-2 family proteins, the majority of AML patients developed acquired resistance of venetoclax (VEN) to combination therapy of VEN with low-dose cytarabine (LDAC) or hypomethylating agents (HMAs). Dysregulation of the Wnt/β-catenin signalling pathway is intently associated with leukemia development and chemotherapy resistance. However, there is currently no Wnt/β-catenin inhibitor approved for clinical use and it is not clear whether targeting the Wnt/β-catenin pathway enhances the anti-leukemic activity of VEN. METHODS: Analysis of the AML patient's data in the BeatAML and GEO databases. Establishing the MOLM13 venetoclax-resistant cell line (MOLM13-R cells) based on the MOLM13 parental cell line. CCK-8, Annexin-V/PI and Western blotting were performed to assess the effects of the combination of Wnt/β-catenin inhibitor C-82 and VEN in AML cell lines. The potential mechanisms of synergistic effects of the two-drug combination were explored by Western blotting and ubiquitination immunoprecipitation. RESULTS: We displayed that the expression of β-catenin abnormally upregulated in AML patients and MOLM13-R cells. Knockdown of β-catenin could increase cell apoptosis in MOLM13-R cells. Combined treatment of C-82 with VEN synergistically inhibited AML cell growth and increased apoptosis. Mechanistically, C-82 disrupted the stability of Mcl-1 protein, and Mcl-1 downregulation was associated with different phosphorylation sites of Mcl-1 and proteasomal degradation. The combination of C-82 and VEN synergistically induced concurrent mitochondrial-associated apoptosis and gasdermin E (GSDME)-dependent pyroptosis. CONCLUSION: Our findings propose an effective treatment strategy for AML patients through the combination of C-82 and VEN, positioning this regimen as a promising therapeutic option.