RUNX inhibitor suppresses graft-versus-host disease through targeting axis.

Patients with refractory graft-versus-host disease (GVHD) have a dismal prognosis. Therefore, novel therapeutic targets are still needed to be identified. Runt-related transcriptional factor (RUNX) family transcription factors are essential transcription factors that mediate the essential roles in effector T cells. However, whether RUNX targeting can suppress, and GVHD is yet unknown. Here, we showed that RUNX family members have a redundant role in directly transactivating expression in T cells. We also found that our novel RUNX inhibitor, Chb-M', which is the inhibitor that switches off the entire RUNX family by alkylating agent-conjugated pyrrole-imidazole (PI) polyamides, inhibited T-cell receptor mediated T cell proliferation and allogenic T cell response. These were designed to specifically bind to consensus RUNX-binding sequences (TGTGGT). Chb-M' also suppressed the expression of and pro-inflammatory cytokine genes in vitro. Using xenogeneic GVHD model, mice injected by Chb-M' showed almost no sign of GVHD. Especially, the CD4 T cell was decreased and GVHD-associated cytokines including tissue necrosis factor-α and granulocyte-macrophage colony-stimulating factor were reduced in the peripheral blood of Chb-M' injected mice. Taken together, our data demonstrates that RUNX family transcriptionally upregulates in T cells, and axis can be a novel therapeutic target against GVHD.