GATA6 identifies an immune-enriched phenotype linked to favorable outcomes in patients with pancreatic cancer undergoing upfront surgery.

This study underscores GATA6's role in distinguishing classical and basal-like pancreatic ductal adenocarcinoma (PDAC) phenotypes. Retrospective studies associate GATA6 immunohistochemistry (IHC) expression with survival outcomes, warranting prospective validation. In a prospective treatment-naive cohort of patients with resected PDAC, GATA6 IHC proves a prognostic discriminator, associating high GATA6 expression with extended survival and the classical PDAC phenotype. However, GATA6's prognostic significance is numerically lower after gemcitabine-based neoadjuvant chemoradiotherapy compared to its significance in patients treated with upfront surgery. Furthermore, GATA6 is implicated in immunomodulation, although a comprehensive investigation of its immunological role is lacking. Treatment-naive PDAC tumors with varying GATA6 expression yield distinct immunological landscapes. Tumors highly expressing GATA6 show reduced infiltration of immunosuppressive regulatory T cells and M2 macrophages but increased infiltration of immune-stimulating, antigen-presenting, and activated T cells. Our findings caution against solely relying on GATA6 for molecular subtyping in clinical trials and open avenues for exploring immune-based combination therapies.

Metformin boosts antitumor immunity and improves prognosis in upfront resected pancreatic cancer: an observational study.

BACKGROUND: Beyond demographic and immune factors, metabolic considerations, particularly metformin's recognized impact in oncology, warrant exploration in treating pancreatic cancer. This study aimed to investigate the influence of metformin on patient survival and its potential correlation with distinct immune profiles in pancreatic ductal adenocarcinoma (PDAC) tumors. METHODS: We included 82 upfront resected and 66 gemcitabine-based neoadjuvant chemoradiotherapy (nCRT)-treated patients from the PREOPANC randomized controlled trial (RCT). Transcriptomic NanoString immunoprofiling was performed for a subset of 96 available resected specimens. RESULTS: Disparities in survival outcomes and immune profiles were apparent between metformin and non-metformin users in upfront resected patients but lacking in nCRT-treated patients. Compared to non-metformin users, upfront resected metformin users showed a higher median overall survival (OS) of 29 vs 14 months and a better 5-year OS rate of 19% vs 5%. Furthermore, metformin use was a favorable prognostic factor for OS in the upfront surgery group (HR = 0.56; 95% CI = 0.32 to 0.99). Transcriptomic data revealed that metformin users significantly underexpressed genes related to pro-tumoral immunity, including monocyte to M2 macrophage polarization and activation. Furthermore, the relative abundance of anti-inflammatory CD163+ MRC1+ M2 macrophages in non-metformin users and immune-activating CD1A+ CD1C+ dendritic cells in metformin users was heightened (P < .001). CONCLUSION: This study unveils immune profile changes resulting from metformin use in upfront resected pancreatic cancer patients, possibly contributing to prolonged survival outcomes. Specifically, metformin use may decrease the abundance and activity of pro-tumoral M2 macrophages and increase the recruitment and function of tumor-resolving DCs, favoring antitumor immunity.[PREOPANC trial EudraCT: 2012-003181-40].

Rintatolimod in Advanced Pancreatic Cancer Enhances Antitumor Immunity through Dendritic Cell-Mediated T-Cell Responses.

PURPOSE: Amid the need for new approaches to improve survival in pancreatic ductal adenocarcinoma (PDAC), immune-based therapies have garnered interest. Rintatolimod, a Toll-like receptor 3 (TLR-3) agonist, is a potential candidate due to its dual impact on restraining PDAC cell functions and boosting the antitumor immune response. This study investigates the effect of TLR-3 activation through rintatolimod on the peripheral immune landscape of patients with advanced PDAC. EXPERIMENTAL DESIGN: Paired blood samples of 30 patients with advanced PDAC, collected at baseline and after 12 rintatolimod intravenous infusions, underwent comprehensive transcriptomic NanoString and proteomic flow cytometry profiling. The impact of rintatolimod and immunologic factors on survival outcomes was assessed through univariate Cox proportional hazards models. RESULTS: Rintatolimod treatment enhances peripheral immune activity at the transcriptomic and proteomic levels, particularly involving type 1 conventional dendritic cells (cDC1) and T cells. Post-rintatolimod, the increased peripheral abundance of BTLA+ XCR1+ cDC1s and CD4+SELL+ T cells correlated with improved clinical outcomes. Patients with stable disease exhibited pronouncedDCand T-cell activation gene overexpression. Notably, the expression of immune checkpoints PD-L1 and PD-L2 decreased post-rintatolimod across all patients. However, those with progressive disease showed increased expression of genes encoding IDO1 and PD-1. CONCLUSIONS: This study presents compelling evidence of the immune-stimulatory properties linked to TLR-3 activation through rintatolimod. Rintatolimod may break immunologic tolerance by enhancing antitumor immunity through DC-mediated Th-cell responses. Furthermore, our findings lay the groundwork for investigating the potential synergy between TLR-3 activation and immune checkpoint inhibitor therapy to improve therapeutic outcomes. See related commentary by Martínez-Riaño et al., p. 3355.