Venetoclax enhances T cell–mediated antileukemic activity by increasing ROS production
Jong Bok Lee, Dilshad H. Khan, Rose Hurren, Mingjing Xu, Yoosu Na, Hyeonjeong Kang, Sara Mirali, Xiaoming Wang, Marcela Gronda, Yulia Jitkova, Neil MacLean, Andrea Arruda, Zoe Alaniz, Marina Konopleva, Michael Andreeff, Mark D. Minden, Zhang Li, Aaron D. Schimmer
Abstract
Venetoclax, a Bcl-2 inhibitor, in combination with the hypomethylating agent azacytidine, achieves complete remission with or without count recovery in ∼70% of treatment-naive elderly patients unfit for conventional intensive chemotherapy. However, the mechanism of action of this drug combination is not fully understood. We discovered that venetoclax directly activated T cells to increase their cytotoxicity against acute myeloid leukemia (AML) in vitro and in vivo. Venetoclax enhanced T-cell effector function by increasing reactive oxygen species generation through inhibition of respiratory chain supercomplexes formation. In addition, azacytidine induced a viral mimicry response in AML cells by activating the STING/cGAS pathway, thereby rendering the AML cells more susceptible to T cell-mediated cytotoxicity. Similar findings were seen in patients treated with venetoclax, as this treatment increased reactive oxygen species generation and activated T cells. Collectively, this study presents a new immune-mediated mechanism of action for venetoclax and azacytidine in the treatment of AML and highlights a potential combination of venetoclax and adoptive cell therapy for patients with AML.