Anlotinib Induced Venetoclax-resistant Acute Myeloid Leukemia Stem Cells Apoptosis through Downregulating Mcl-1-mediated Anti-apoptoeic Pathway

Acute myeloid leukemia (AML) is characterized by uncontrolled proliferation of leukemia stem cells (LSCs), which drive relapse and therapeutic resistance through mechanisms such as Mcl-1–mediated apoptosis evasion. Venetoclax, a selective Bcl-2 inhibitor, induces apoptosis in LSCs but is limited by acquired resistance. Anlotinib, a multi-target tyrosine kinase inhibitor, has demonstrated potential to overcome resistance by disrupting prosurvival signaling. This study investigated the synergistic antileukemic effects of Anlotinib and Venetoclax in overcoming Mcl-1–mediated resistance in AML LSCs. AML cell lines (Kasumi-1 and KG-1α) and primary CD34⁺CD38⁻ LSCs from patients (n = 31) were treated with Anlotinib, Venetoclax, or both. Cell viability and apoptosis were measured by CCK-8 and Annexin V/PI assays, while transcriptome sequencing and Western blot analyses elucidated the underlying molecular mechanisms. The combination therapy significantly enhanced apoptosis and inhibited proliferation in Venetoclax-resistant AML cells and LSCs compared with monotherapies. Mechanistically, Anlotinib potentiated Venetoclax by downregulating VEGFR2 and suppressing the PI3K/AKT/mTOR pathway, while the combination further inhibited the VEGFR2/SOS1/p38 axis, leading to decreased Mcl-1 expression. Immunoprecipitation confirmed that SOS1 promoted p-p38 accumulation, which was blocked by combination treatment. In NCG mice engrafted with primary AML cells, co-administration of Anlotinib and Venetoclax markedly reduced tumor burden and decreased p-p38 and p-AKT levels in xenograft tissues. These findings indicate that Anlotinib enhances Venetoclax sensitivity by targeting VEGFR2-dependent signaling and overcoming Mcl-1–mediated resistance, providing a promising therapeutic strategy for refractory AML.