GITR agonistic stimulation enhances the anti-tumor immune response in a mouse model of ESCC.

Esophageal cancer is a significant health burden in the United States and worldwide and is the 8th leading cause of cancer-related death. Over 90% of esophageal cancers are squamous cell cancers (ESCC). Despite the development of new therapies, the overall 5-year survival rate remains lower than 20%. Recent clinical trials of immunotherapy approaches in ESCC have shown that blocking PD-1/PD-L1 interactions can reduce tumor burden and increase survival, but this only occurs in a fraction of patients. This emphasizes the need for additional therapeutic options to improve overall response rates, duration of response, and overall survival. Glucocorticoid-induced TNFR-related protein (GITR) stimulation has emerged as a promising immunotherapy target, as its stimulation appears to promote tumor regression. In this study, we evaluated the consequences of GITR agonistic stimulation with the DTA-1 antibody (anti-GITR agonist) on esophageal squamous cell carcinoma (ESCC) progression. Increased expression of GITR was observed in esophageal tumors from ESCC patients in comparison to normal adjacent tissue and in a mouse model of ESCC. 100% of mice treated with 4-NQO/IgG control antibody developed invasive squamous cell carcinoma. Less advanced esophageal tumors were seen in mice treated with 4-NQO/anti-GITR agonist compared to 4-NQO/IgG treatment. 4-NQO/anti-GITR agonist-treated mice demonstrated a significant increase in mucosal CTL/Treg ratios as well as decreased gene expression profiles of pathways related to esophageal squamous cell carcinogenesis. Thus, GITR agonism merits further study as a treatment strategy for ESCC patients.

IκB Kinase-ß Regulates Neutrophil Recruitment Through Activation of STAT3 Signaling in the Esophagus.

BACKGROUND & AIMS: The epithelial barrier is the host's first line of defense against damage to the underlying tissue. Upon injury, the epithelium plays a critical role in inflammation. The IκB kinase ß (IKKß)/nuclear factor-κB pathway was shown to be active in the esophageal epithelium of patients with esophageal disease. However, the complex mechanisms by which IKKß signaling regulates esophageal disease pathogenesis remain unknown. Our prior work has shown that expression of a constitutively active form of IKKß specifically in esophageal epithelia of mice (IkkßcaEsophageal Epithelial Cell-Knockin (EEC-KI)) is sufficient to cause esophagitis. METHODS: We generated ED-L2/Cre;Rosa26-Ikkßca+/L;Stat3L/L (IkkßcaEEC-KI;Stat3Esophageal Epithelial Cell Knockout (EEC-KO)) mice, in which the ED-L2 promoter activates Cre recombinase in the esophageal epithelium, leading to constitutive activation of IKKß and loss of Stat3. Esophageal epithelial tissues were collected and analyzed by immunostaining, RNA sequencing, quantitative real-time polymerase chain reaction assays, flow cytometry, and Western blot. IkkßcaEEC-KI mice were treated with neutralizing antibodies against interleukin (IL)23p19 and IL12p40. RESULTS: Here, we report that IkkßcaEEC-KI mice have increased activation of epithelial Janus kinase 2/STAT3 signaling. Stat3 deletion in IkkßcaEEC-KI mice attenuated the neutrophil infiltration observed in IkkßcaEEC-KI mice and resulted in decreased expression of genes related to immune cell recruitment and activity. Blocking experiments in IkkßcaEEC-KI mice showed that STAT3 activation and subsequent neutrophil recruitment are dependent on IL23 secretion. CONCLUSIONS: Our study establishes a novel interplay between IKKß and STAT3 signaling in epithelial cells of the esophagus, where IKKß/IL23/STAT3 signaling controls neutrophil recruitment during the onset of inflammation. GEO accession number: GSE154129.