Venetoclax Enhances Human Γδt Cells Anti-Leukemia Immunity through Metabolic Reprogramming

Background:

Despite recent therapeutic advances, patients with relapsed/refractory acute myeloid leukemia (r/r AML) have limited treatment options and poor prognosis. Allogeneic and autologous gamma delta (γδ) T cell-based therapies have been explored for a long time and proven to be safe in patients through multiple clinical trials. However, quite a few AML blasts obtained from r/r AML patients show resistance to γδ T cell-mediated cytotoxicity.

The primary aim of this research is to explore the augmentation of anti-AML immunity in human γδT cells. This study systematically evaluates various therapeutic agents currently in clinical use to identify those that can potentiate the anti-tumor activities of γδT cells in these resistant patient populations. Preliminary data suggest that Venetoclax markedly increases the anti-tumor capabilities of double negative T cells and natural killer cells. Ultimately, this investigation seeks to foster the development of innovative treatments that improve clinical responses in AML patients resistant to traditional γδT cell-based therapies.

Methods:

Human γδT cells were isolated from peripheral blood mononuclear cells and treated with various pharmacological agents at clinically relevant concentrations. Cells were washed with phosphate-buffered saline and then co-cultured with AML cells. The viability of AML cells was assessed 8~18h later, allowing for the measurement of γδT cell-mediated cytotoxicity. Expression of key immunological markers on γδT cells was analyzed via flow cytometry. Non-targeted metabolomics analysis using liquid chromatography-mass spectrometry identified differentially expressed metabolites, revealing the metabolic alterations caused by the treatments.

Results:

Among several pharmacological agents, such as Venetoclax, Enasidenib, Azacytine, Selinexor, Decitabine, Chidamise, Linperlisib and Cytarabine, Venetoclax treatment significantly enhanced the anti-tumor efficacy of γδT cells against the γδT cell-resistant AML cell line and patient-derived cells, achieving a 49.21% killing efficiency in venetoclax-treated γδT cells compared to 5.06% with untreated cells. Combining Venetoclax with γδT cells decreased tumor burden in THP-1-bearing mice. We found upregulated activation markers CD25 and CD69 and cytotoxic molecules NKG2D and DNAM-1 on drug-treated γδT cells when these cells were exposed to tumor targets. Additionally, drug-treated γδT cells expressing higher stem cell memory markers (CD45RA⁺CD62L⁺) and increased proliferation marker Ki67. Metabolically, drug-treated γδT cells showed a shift towards lipid synthesis, which likely supports the enhanced proliferation and stem memory phenotype.

Conclusions

In conclusion, our study suggests that integrating venetoclax into γδT cell therapies could significantly improve the efficacy of these treatments, providing a more robust and sustained immune response against AML. The ability of venetoclax to potentiate the natural cytotoxic functions of γδT cells and promote a metabolic state conducive to long-lasting cytotoxicity offers a dual mechanism of action that could overcome some of the traditional challenges faced in targeting AML. The convergence of cellular therapy with targeted drug treatment, as evidenced by the efficacy of venetoclax in our research, represents a novel and exciting direction in cancer immunotherapy.