Knockout Tumor Microenvironment HO-1 Neutralizes Myeloid-Derived Suppressor Cells and Enhances the Antitumor Effect of PD-1 Inhibition in Murine Models of Acute Myeloid Leukemia

Background/Aims: Myeloid-derived suppressor cells (MDSCs) has been shown to be involved in tumor immune escape mechanisms and B cell-specific immunity in Acute myeloid leukemia (AML) patients. In our previous study shown that HO-1 protein have immunomodulatory activity including targeting of immune suppressor cells in the tumor microenvironment. Thus, we decided to assess whether HO-1 could enhance anti-PD-1 treatment and investigate those alterations in the immunosuppressive tumor microenvironment that contribute to the combined antitumor activity.