PT - JOURNAL ARTICLE AU - Graziano, Vincenzo AU - Dannhorn, Andreas AU - Hulme, Heather AU - Williamson, Kate AU - Buckley, Hannah AU - Karim, Saadia A AU - Wilson, Matthew AU - Lee, Sheng Y AU - Kaistha, Brajesh P AU - Islam, Sabita AU - Thaventhiran, James E D AU - Richards, Frances M AU - Goodwin, Richard AU - Brais, Rebecca AU - Morton, Jennifer P AU - Dovedi, Simon J AU - Schuller, Alwin G AU - Eyles, Jim AU - Jodrell, Duncan I TI - Defining the spatial distribution of extracellular adenosine revealed a myeloid-dependent immunosuppressive microenvironment in pancreatic ductal adenocarcinoma AID - 10.1136/jitc-2022-006457 DP - 2023 Aug 01 TA - Journal for ImmunoTherapy of Cancer PG - e006457 VI - 11 IP - 8 4099 - http://jitc.bmj.com/content/11/8/e006457.short 4100 - http://jitc.bmj.com/content/11/8/e006457.full SO - J Immunother Cancer2023 Aug 01; 11 AB - Background The prognosis for patients with pancreatic ductal adenocarcinoma (PDAC) remains extremely poor. It has been suggested that the adenosine pathway contributes to the ability of PDAC to evade the immune system and hence, its resistance to immuno-oncology therapies (IOT), by generating extracellular adenosine (eAdo).Methods Using genetically engineered allograft models of PDAC in syngeneic mice with defined and different immune infiltration and response to IOT and autochthonous tumors in KPC mice we investigated the impact of the adenosine pathway on the PDAC tumor microenvironment (TME). Flow cytometry and imaging mass cytometry (IMC) were used to characterize the subpopulation frequency and spatial distribution of tumor-infiltrating immune cells. Mass spectrometry imaging (MSI) was used to visualize adenosine compartmentalization in the PDAC tumors. RNA sequencing was used to evaluate the influence of the adenosine pathway on the shaping of the immune milieu and correlate our findings to published data sets in human PDAC.Results We demonstrated high expression of adenosine pathway components in tumor-infiltrating immune cells (particularly myeloid populations) in the murine models. MSI demonstrated that extracellular adenosine distribution is heterogeneous in tumors, with high concentrations in peri-necrotic, hypoxic regions, associated with rich myeloid infiltration, demonstrated using IMC. Protumorigenic M2 macrophages express high levels of the Adora2a receptor; particularly in the IOT resistant model. Blocking the in vivo formation and function of eAdo (Adoi), using a combination of anti-CD73 antibody and an Adora2a inhibitor slowed tumor growth and reduced metastatic burden. Additionally, blocking the adenosine pathway improved the efficacy of combinations of cytotoxic agents or immunotherapy. Adoi remodeled the TME, by reducing the infiltration of M2 macrophages and regulatory T cells. RNA sequencing analysis showed that genes related to immune modulation, hypoxia and tumor stroma were downregulated following Adoi and a specific adenosine signature derived from this is associated with a poorer prognosis in patients with PDAC.Conclusions The formation of eAdo promotes the development of the immunosuppressive TME in PDAC, contributing to its resistance to conventional and novel therapies. Therefore, inhibition of the adenosine pathway may represent a strategy to modulate the PDAC immune milieu and improve therapy response in patients with PDAC.Data are available in a public, open access repository. Data are available upon reasonable request. All data relevant to the study are included in the article or uploaded as supplementary information. The data generated in this study are available within the article and its supplementary data files or from the corresponding authors upon reasonable request. Code for differential expression analysis and visualization of RNAseq data is available via Github https://github.com/ka-lw/AdenoPDAC.