RUNX2 transcriptional activity is required for CD26high CD4+ T cell development

Abstract

Abstract Adoptive T cell therapy (ACT) is rapidly growing as a promising treatment option for patients who relapse or fail to respond to immunotherapy. However, in the treatment of solid tumors with ACT, many therapies fail to maintain long-term durability. We posit that CD4+ T cells expressing high levels of CD26 (CD26high T cells) would be a potent ACT product. We previously reported that they express an array of chemokine receptors, dynamic cytokine profile and regressed tumors better than other T helper subsets. Here, we developed novel cytokine priming strategies to enrich CD26high T cells from the blood of healthy donors and cancer patients. We identified a unique suite of transcription factors, including RUNX2, that are elevated on CD26high T cells. We also discovered that CD26high T cells overexpress a distinct patterns of cytokine receptor including IL-2Ra, IL-7R, IL-18R and IL-12Rβ1. Targeting these receptors via recombinant cytokine priming strategies resulted in three-to-five-fold expansion of CD26high T cells from bulk or Naive CD4+ T cells. Inhibiting RUNX2 DNA binding via small molecule inhibitors CADD522 and DIPQUO resulted significant reduction in development of CD26high CD4 T cells and decreased their cytokine production. These data suggest that RUNX2 may regulate the development and function of CD26high CD4 T cells. Taken together, these results provide evidence for the use of CD26high CD4 T cells in the treatment of solid malignancies with ACT.