Synthetic RORγ agonists regulate multiple pathways to enhance antitumor immunity

Abstract

RORγt is the key transcription factor controlling the development and function of CD4+ Th17 and CD8+ Tc17 cells. Across a range of human tumors, about 15% of the CD4+ T cell fraction in tumor-infiltrating lymphocytes are RORγ+ cells. To evaluate the role of RORγ in antitumor immunity, we have identified synthetic, small molecule agonists that selectively activate RORγ to a greater extent than the endogenous agonist desmosterol. These RORγ agonists enhance effector function of Type 17 cells by increasing the production of cytokines/chemokines such as IL-17A and GM-CSF, augmenting expression of co-stimulatory receptors like CD137, CD226, and improving survival and cytotoxic activity. RORγ agonists also attenuate immunosuppressive mechanisms by curtailing Treg formation, diminishing CD39 and CD73 expression, and decreasing levels of co-inhibitory receptors including PD-1 and TIGIT on tumor-reactive lymphocytes. The effects of RORγ agonists were not observed in RORγ−/− T cells, underscoring the selective on-target activity of the compounds. In vitro treatment of tumor-specific T cells with RORγ agonists, followed by adoptive transfer to tumor-bearing mice is highly effective at controlling tumor growth while improving T cell survival and maintaining enhanced IL-17A and reduced PD-1 in vivo. The in vitro effects of RORγ agonists translate into single agent, immune system-dependent, antitumor efficacy when compounds are administered orally in syngeneic tumor models. RORγ agonists integrate multiple antitumor mechanisms into a single therapeutic that both increases immune activation and decreases immune suppression resulting in robust inhibition of tumor growth. Thus, RORγ agonists represent a novel immunotherapy approach for cancer.

In Vitro Priming of Adoptively Transferred T Cells with a RORγ Agonist Confers Durable Memory and Stemness In Vivo

“…1B). Consistent with the findings in mouse T cells (11), this in vitro agonist treatment induced the cells to produce 6-fold more IL17A without compromising their ability to produce IFNγ (Fig. 1C and D).…”

“…We reported that a series of RORγ agonists could augment the effector function of murine Type 17 T cells in vitro and improve their antitumor activity when administered as an oral therapy in mice bearing syngeneic tumors (11). To extend these results and evaluate how RORγ agonists would affect human chimeric antigen receptor (CAR) T cells, human total T (CD4 + and CD8 + ) cells were enriched from the peripheral blood of healthy individuals, programmed using Type 17 polarizing conditions (IL1β, IL6, IL23), activated with anti-CD3/CD28 beads and 1 day after activation, transduced with a lentiviral vector that encodes a CAR recognizing mesothelin (Fig.…”

“…This heightened presence of Type 17 cells in tumor tissue holds true for many types of malignancies, implying that tumors themselves produce factors that promote RORγt expression. Approximately 15% of human CD4 + T cells in tumors express RORγt and this transcription factor is induced by cytokines TGFβ and IL6, both produced at high levels in inflamed tissues and transformed cells (11). We reported that RORγ activation with a novel small molecule agonist potentiates the function of antitumor Th17 cells to a greater extent than the endogenous agonist desmosterol (11, 12).…”

“…Approximately 15% of human CD4 + T cells in tumors express RORγt and this transcription factor is induced by cytokines TGFβ and IL6, both produced at high levels in inflamed tissues and transformed cells (11). We reported that RORγ activation with a novel small molecule agonist potentiates the function of antitumor Th17 cells to a greater extent than the endogenous agonist desmosterol (11, 12). This activation is associated with enhanced cytokine production and CTL activity as well as reduced Treg formation in vitro and effective antitumor immunity in syngeneic models (11).…”

“…We reported that RORγ activation with a novel small molecule agonist potentiates the function of antitumor Th17 cells to a greater extent than the endogenous agonist desmosterol (11, 12). This activation is associated with enhanced cytokine production and CTL activity as well as reduced Treg formation in vitro and effective antitumor immunity in syngeneic models (11). …”