Tumor cell–intrinsic EPHA2 suppresses antitumor immunity by regulating PTGS2 (COX-2)
Nune Markosyan, … , Ben Z. Stanger, Robert H. Vonderheide
Nune Markosyan, … , Ben Z. Stanger, Robert H. Vonderheide
Published June 4, 2019
Citation Information: J Clin Invest. 2019;129(9):3594-3609. https://doi.org/10.1172/JCI127755.
View: Text | PDF
Research Article Immunology Oncology

Tumor cell–intrinsic EPHA2 suppresses antitumor immunity by regulating PTGS2 (COX-2)

Abstract

Resistance to immunotherapy is one of the biggest problems of current oncotherapeutics. While T cell abundance is essential for tumor responsiveness to immunotherapy, factors that define the T cell–inflamed tumor microenvironment are not fully understood. We used an unbiased approach to identify tumor-intrinsic mechanisms shaping the immune tumor microenvironment (TME), focusing on pancreatic adenocarcinoma because it is refractory to immunotherapy and excludes T cells from the TME. From human tumors, we identified ephrin-A receptor 2 (EPHA2) as a candidate tumor-intrinsic driver of immunosuppression. Epha2 deletion reversed T cell exclusion and sensitized tumors to immunotherapy. We found that prostaglandin endoperoxide synthase 2 (PTGS2), the gene encoding cyclooxygenase-2, lies downstream of EPHA2 signaling through TGF-β and is associated with poor patient survival. Ptgs2 deletion reversed T cell exclusion and sensitized tumors to immunotherapy; pharmacological inhibition of PTGS2 was similarly effective. Thus, EPHA2/PTGS2 signaling in tumor cells regulates tumor immune phenotypes; blockade may represent a therapeutic avenue for immunotherapy-refractory cancers. Our findings warrant clinical trials testing the effectiveness of therapies combining EPHA2/TGF-β/PTGS2 pathway inhibitors with antitumor immunotherapy and may change the treatment of notoriously therapy-resistant pancreatic adenocarcinoma.

Authors

Nune Markosyan, Jinyang Li, Yu H. Sun, Lee P. Richman, Jeffrey H. Lin, Fangxue Yan, Liz Quinones, Yogev Sela, Taiji Yamazoe, Naomi Gordon, John W. Tobias, Katelyn T. Byrne, Andrew J. Rech, Garret A. FitzGerald, Ben Z. Stanger, Robert H. Vonderheide

×

Figure 5

Ptgs2 deletion suppresses PDA growth.

Options: View larger image (or click on image) Download as PowerPoint
Ptgs2 deletion suppresses PDA growth. (A) Graphic representation of pan...
(A) Graphic representation of pancreatic epithelial cell Ptgs2-deficient KPCY mouse. (B) PTGS2 protein staining (brown) in pancreatic ductal epithelial cells (arrows) of non–tumor-bearing mice (3–4 mice/group). Original magnification, ×20. (C) Kaplan-Meier curves of tumor-free (left) and overall survival (right) of KPCY and KPCYPtgs2 mice. Number of mice per group indicated in parentheses. (D) Extracellular prostanoid levels measured in control (nontarget shRNA transduced) cell lines cultured for 72 hours (n = 6/group). (E) Relative expression of Ptgs2 mRNA (left) and PGE2 levels (right) in control (same as in D) and Ptgs2-KD (Ptgs2 shRNA) KPCY cell lines after 72 hours in culture (n = 6/group). (F) Control and Ptgs2-KD KPCY cell lines injected in syng8eneic CY mice receiving either isotype control (IgG) or anti-CD4– and anti-CD8–depleting antibodies (aCD4/aCD8; n = 8-9/group); tumor-free survival (left) and tumor growth (right). (G) Control and Ptgs2-KD KPCY cell lines injected in syngeneic CY mice on regular chow (control) or 100 mg/kg celecoxib diet starting day 0 (ctrl + X; n = 9–12/group); tumor-free survival (left) and tumor growth (right). (H) Control (Cas9 only transduced) and Ptgs2-KO (Cas9/ Ptges2 gRNA transduced) KPC cell lines injected in WT mice receiving either isotype control (IgG) or anti-CD4– and anti-CD8– depleting (aCD4/aCD8) antibodies (n = 5-9/group); tumor-free survival (left) and tumor growth (right). (D and E) Data are presented as boxplots, with horizontal lines and error bars indicating mean and range, respectively. Statistical significance measured by Student’s unpaired t test (E). The log-rank P values for C were calculated in GraphPad Prism. Statistical analyses of tumor growth and survival for (F–H) performed using linear mixed-effects model with Tukey’s HSD post test using the lme4 and the survival package in R. *P < 0.05; **P < 0.01; ****P < 0.0001.