Project description:The discovery of immune checkpoint inhibitor (ICI) has highlighted the clinical importance of immune evasion in cancer. However, only a fraction of cancer patients show response to ICI, raising a question on immune suppression mechanisms other than immune checkpoint. In this study, we examined the role of the lipid inflammatory mediator PGE2 in immune evasion of the ICI-insensitive Lewis Lung Carcinoma line 1 (LLC1) mouse model. Inhibition of PGE receptors, EP2 and EP4, significantly suppressed tumor growth through the modulation of host immune cells. Single cell RNA-sequencing analysis revealed that EP2/4 inhibition elicited anti-tumor immunity through the reprogramming of inflammatory myeloid cells by downregulating expression of genes in NFB signaling and actions and suppression of the mregDC-regulatory T cell axis by downregulating genes associated with regulatory T cell recruitment and activation. Taken together, our work suggests that PGE2-EP2/EP4 signaling induces proinflammatory myeloid and tolerogenic lymphoid environments in ICI-insensitive tumors, which is amenable to EP2 and EP4 inhibitors..
Project description:While the role of prostaglandin E2 (PGE2) in promoting malignant progression is well-established, how to optimally block the activity of PGE2 signaling remains to be demonstrated. Clinical trials with prostaglandin pathway targeted agents have shown activity but without sufficient significance or dose-limiting toxicities that have prevented approval. PGE2 signals through four receptors (EP1-4) to modulate tumor progression. EP2 and EP4 signaling exacerbates tumor pathology and is immunosuppressive through potentiating cAMP production. EP1 and EP3 signaling has the opposite effect through increasing IP3 and decreasing cAMP. Using available small molecule antagonists of single EP receptors, the COX-2 inhibitor celecoxib, or a novel dual EP2/EP4 antagonist generated in this investigation, we tested which approach to block PGE2 signaling optimally restored immunologic activity in mouse and human immune cells and antitumor activity in syngeneic, spontaneous and xenograft tumor models. We found that dual antagonism of EP2 and EP4 together significantly enhanced the activation of PGE2-suppressed mouse and human monocytes and CD8+ T cells in vitro as compared to single EP antagonists. CD8+ T cell activation was dampened by single EP1 and EP3 antagonists. Dual EP2/EP4 PGE2 receptor antagonists increased TME lymphocyte infiltration and significantly reduced disease burden in multiple tumor models, including in the adenomatous polyposis coli (APC)min+/- spontaneous colorectal tumor model, compared to celecoxib. These results support a hypothesis that redundancy of EP2 and EP4 receptor signaling necessitates a therapeutic strategy of dual blockade of EP2 and EP4. Here we describe TPST-1495, a first-in-class orally available small molecule dual EP2/EP4 antagonist.
Project description:RNA sequencing was used to determine the impact of PGE2 signaling on NK cell function. Our analysis revealed that PGE2 induces a dysfunctional program in NK cells characterized by the inability to produce cytokines and chemokines upon their activation. Mechanistically, this program is governed by transcriptional changes downstream of the PGE2 receptors EP2 and EP4.
Project description:ATAC sequencing was used to determine the impact of PGE2 signaling on NK cell function. Our analysis revealed that PGE2 induces a dysfunctional program in NK cells characterized by the inability to produce cytokines and chemokines upon their activation. Mechanistically, this program is governed by epigenetic changes downstream of the PGE2 receptors EP2 and EP4.
Project description:Foxp3+ regulatory T cells (Tregs) heavily infiltrate malignant tumors and restrict anti-tumor immunity. These tumor-infiltrating Tregs (TI-Tregs) adopt a distinct phenotype by expressing a unique set of genes including those encoding various co-stimulatory and co-inhibitory molecules. This TI-Treg gene expression signature is conserved in TI-Tregs across species and the types and stages of tumors, suggesting the presence of a common inducing mechanism or mechanisms in tumor microenvironment (TME). However, identity of such a mechanism remains elusive. Here, we show that prostaglandin E2 (PGE2) produced in TME directly acts on its receptor EP2/EP4 on Tregs to induce the TI-Treg phenotype. Indeed, PGE2 added to TCR-activated Tregs induces a set of genes, many of which are included in the reported TI-Treg signature genes, in both induced Tregs (iTregs) and naturally occurring Tregs (nTregs), in a manner dependent on EP2 and EP4 via cAMP-PKA pathway. This is not limited to phenotypic changes, as EP4 agonist-treated Tregs exhibit potent suppressive activity to CD8+ T cells and strongly inhibit their proliferation and survival. Consistently, selective loss of EP2 and EP4 in mouse Tregs and pharmacological inhibition of EP2 and EP4 reduce expression of those genes in Tregs infiltrating LLC1 mouse syngeneic tumor, and significantly delay the tumor progression. In human FOXP3+iTregs, the expression of Treg signature genes, FOXP3, CD25 and CTLA4 as well as a typical TI-Treg signature gene, 4-1BB are significantly upregulated by PGE2-EP4 signaling. Furthermore, analysis of scRNA-seq of nasopharyngeal cancer patients demonstrates preferential expression of the TI-Treg signature genes in Tregs infiltrating the PTGShi tumor group compared to the PTGS2lo tumor group. These findings suggest that PGE2-EP2/EP4 signaling is one of the molecular mechanisms inducing the TI-Treg phenotype in TME.
Project description:Foxp3+ regulatory T cells (Tregs) heavily infiltrate malignant tumors and restrict anti-tumor immunity. These tumor-infiltrating Tregs (TI-Tregs) adopt a distinct phenotype by expressing a unique set of genes including those encoding various co-stimulatory and co-inhibitory molecules. This TI-Treg gene expression signature is conserved in TI-Tregs across species and the types and stages of tumors, suggesting the presence of a common inducing mechanism or mechanisms in tumor microenvironment (TME). However, identity of such a mechanism remains elusive. Here, we show that prostaglandin E2 (PGE2) produced in TME directly acts on its receptor EP2/EP4 on Tregs to induce the TI-Treg phenotype. Indeed, PGE2 added to TCR-activated Tregs induces a set of genes, many of which are included in the reported TI-Treg signature genes, in both induced Tregs (iTregs) and naturally occurring Tregs (nTregs), in a manner dependent on EP2 and EP4 via cAMP-PKA pathway. This is not limited to phenotypic changes, as EP4 agonist-treated Tregs exhibit potent suppressive activity to CD8+ T cells and strongly inhibit their proliferation and survival. Consistently, selective loss of EP2 and EP4 in mouse Tregs and pharmacological inhibition of EP2 and EP4 reduce expression of those genes in Tregs infiltrating LLC1 mouse syngeneic tumor, and significantly delay the tumor progression. In human FOXP3+iTregs, the expression of Treg signature genes, FOXP3, CD25 and CTLA4 as well as a typical TI-Treg signature gene, 4-1BB are significantly upregulated by PGE2-EP4 signaling. Furthermore, analysis of scRNA-seq of nasopharyngeal cancer patients demonstrates preferential expression of the TI-Treg signature genes in Tregs infiltrating the PTGS2hi tumor group compared to the PTGS2lo tumor group. These findings suggest that PGE2-EP2/EP4 signaling is one of the molecular mechanisms inducing the TI-Treg phenotype in TME.
Project description:Foxp3+ regulatory T cells (Tregs) heavily infiltrate malignant tumors and restrict anti-tumor immunity. These tumor-infiltrating Tregs (TI-Tregs) adopt a distinct phenotype by expressing a unique set of genes including those encoding various co-stimulatory and co-inhibitory molecules. This TI-Treg gene expression signature is conserved in TI-Tregs across species and the types and stages of tumors, suggesting the presence of a common inducing mechanism or mechanisms in tumor microenvironment (TME). However, identity of such a mechanism remains elusive. Here, we show that prostaglandin E2 (PGE2) produced in TME directly acts on its receptor EP2/EP4 on Tregs to induce the TI-Treg phenotype. Indeed, PGE2 added to TCR-activated Tregs induces a set of genes, many of which are included in the reported TI-Treg signature genes, in both induced Tregs (iTregs) and naturally occurring Tregs (nTregs), in a manner dependent on EP2 and EP4 via cAMP-PKA pathway. This is not limited to phenotypic changes, as EP4 agonist-treated Tregs exhibit potent suppressive activity to CD8+ T cells and strongly inhibit their proliferation and survival. Consistently, selective loss of EP2 and EP4 in mouse Tregs and pharmacological inhibition of EP2 and EP4 reduce expression of those genes in Tregs infiltrating LLC1 mouse syngeneic tumor, and significantly delay the tumor progression. In human FOXP3+iTregs, the expression of Treg signature genes, FOXP3, CD25 and CTLA4 as well as a typical TI-Treg signature gene, 4-1BB are significantly upregulated by PGE2-EP4 signaling. Furthermore, analysis of scRNA-seq of nasopharyngeal cancer patients demonstrates preferential expression of the TI-Treg signature genes in Tregs infiltrating the PTGS2hi tumor group compared to the PTGS2lo tumor group. These findings suggest that PGE2-EP2/EP4 signaling is one of the molecular mechanisms inducing the TI-Treg phenotype in TME.
Project description:Foxp3+ regulatory T cells (Tregs) heavily infiltrate malignant tumors and restrict anti-tumor immunity. These tumor-infiltrating Tregs (TI-Tregs) adopt a distinct phenotype by expressing a unique set of genes including those encoding various co-stimulatory and co-inhibitory molecules. This TI-Treg gene expression signature is conserved in TI-Tregs across species and the types and stages of tumors, suggesting the presence of a common inducing mechanism or mechanisms in tumor microenvironment (TME). However, identity of such a mechanism remains elusive. Here, we show that prostaglandin E2 (PGE2) produced in TME directly acts on its receptor EP2/EP4 on Tregs to induce the TI-Treg phenotype. Indeed, PGE2 added to TCR-activated Tregs induces a set of genes, many of which are included in the reported TI-Treg signature genes, in both induced Tregs (iTregs) and naturally occurring Tregs (nTregs), in a manner dependent on EP2 and EP4 via cAMP-PKA pathway. This is not limited to phenotypic changes, as EP4 agonist-treated Tregs exhibit potent suppressive activity to CD8+ T cells and strongly inhibit their proliferation and survival. Consistently, selective loss of EP2 and EP4 in mouse Tregs and pharmacological inhibition of EP2 and EP4 reduce expression of those genes in Tregs infiltrating LLC1 mouse syngeneic tumor, and significantly delay the tumor progression. In human FOXP3+iTregs, the expression of Treg signature genes, FOXP3, CD25 and CTLA4 as well as a typical TI-Treg signature gene, 4-1BB are significantly upregulated by PGE2-EP4 signaling. Furthermore, analysis of scRNA-seq of nasopharyngeal cancer patients demonstrates preferential expression of the TI-Treg signature genes in Tregs infiltrating the PTGS2hi tumor group compared to the PTGS2lo tumor group. These findings suggest that PGE2-EP2/EP4 signaling is one of the molecular mechanisms inducing the TI-Treg phenotype in TME.
Project description:IL-23 induces ptgs2 encoding cyclooxygenase 2 in Th17 cells and produces PGE2, which acts back on PGE2 receptors EP2 and EP4 in these cells and enhances IL-23-induced expression of an IL-23 receptor subunit gene, Il23r, by activating STAT3, CREB1 and NF-κB through cAMP-protein kinase A signaling. This PGE2 signaling also induces expression of various inflammation-related genes, which possibly function in Th17 cell-mediated pathology. Combined deletion of EP2 and EP4 selectively in T cells suppressed accumulation of IL-17A+ and IL-17A+IFN-γ+ pathogenic Th17 cells and abolished skin inflammation in IL-23-induced psoriasis mouse model. Analysis of human psoriatic skin biopsies shows positive correlation between PGE2 signaling and the IL-23/Th17 pathway.