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Pancreatic ductal adenocarcinoma (PDAC) is one of the leading causes of cancer-related death in the United States. Recently, intensive research has revealed the remarkable heterogeneity and complexity of the different components in the pancreatic cancer tumor microenvironment. However, our knowledge regarding active stroma (dominated with activated cancer-associated fibroblasts), infiltrated immune cells and actual tumor cells interactions in the tumor microenvironment, and how these interactions impact patient outcomes, remains limited. Digital spatial profiling (DSP) technology now allows us to quantitatively analyze transcript and protein expression on intact tissue, offering an opportunity to study the intra-tumor cell-to-cell communication. Formalin-fixed paraffin-embedded (FFPE) pancreatic tumors from patients with shorter survival (DFS < 12 months, n=2), and longer survival (DFS > 36 months, n=2) were recruited in this study. Immunofluorescent histochemistry staining of tissue morphology identification uses antibodies to pan-cytokeratin (panCK+) for PDAC cells, alpha-smooth muscle actin (aSMA+) for cancer-associated fibroblasts (CAFs). Six replicated regions of interest (ROI) of tumor, CAFs adjacent and distal to tumor area were annotated from each tissue sample and a panel of 78 transcripts (73 target genes and 5 reference genes) were profiled using GeoMx DSP (Nanostring). Person’s correlation (R2) was computed for regression of GeoMx DSP data. All statistical analyses were performed using the GraphPad Prism software. p-values were calculated on two-sided t-tests and p < 0.05 was considered statistically significant. As expected, the morphologic selection successfully separates panCK+ PDAC cells from CAFs demonstrated by the correspondent expression of epithelial genes of EpCam and KRT, allowing single cell profiling. Within the panel of 78 genes, 9 genes (approximal 12%) were detected with significantly higher expression levels in PDAC cells than CAFs. Five genes (BATF3, IL12b, ITGB8, CD4 and IFNAR1) were found increased expression levels in CAFs-adj comparing to CAFs-dis, regulating molecular functions of Organismal Death (p value = 3.88E-03), Maturation of Cells (p value = 2.94E-06), and Migration of Cells (p value = 2.37E-03). When comparing the differential transcriptomes in PDAC cells between the longer and shorter survival groups, higher expression of antigen presentation gene HLA-E and integrin alpha- and beta- family genes (ITGAV, ITGAX, ITGB2, and ITGB8) was seen in longer-lived patients. Proliferation genes (CCND1 and MKI67) were also found to be increased in CAFs in patients with longer survival. Our results suggest that further exploration of gene and protein expression and interactions within the pancreatic tumor microenvironment may improve our understanding of tumor and stromal communication and how it impacts on patient outcomes. Citation Format: Gerik W Tushoski, Dongtao Ann Fu, Lingsong Meng, Kelly Herremans, Andrea N Riner, Christopher E Forsmark, Zhiguang Huo, Steven J Hughes, Song Han. Digital spatial profiling for determination of pancreatic stromal components and correlation with survival [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5676.

Cancer cells exert mastery over the local tumor-associated stroma (TAS) to configure protective immunity within the tumor microenvironment. The immunomodulatory character of pancreatic lysates of patients with cancer differs from those with pancreatitis. In this study, we evaluated the cross-talk between pancreatic cancer and its TAS in primary human cell culture models. Upon exposure of TAS to pancreatic cancer cell-conditioned media, we documented robust secretion of IL6 and IL8. This TAS response was MyD88-dependent and sufficient to directly suppress both CD4+ and CD8+ T-cell proliferation, inducing Th17 polarization at the expense of Th1. We found that patients possessed a similar shift in circulating effector memory Th17:Th1 ratios compared with healthy controls. The TAS response also directly suppressed CD8+ T-cell–mediated cytotoxicity. Overall, our results demonstrate how TAS contributes to the production of an immunosuppressive tumor microenvironment in pancreatic cancer. Cancer Res; 77(3); 672–83. ©2016 AACR.

We previously reported that within the pancreatic ductal adenocarcinoma (PDAC) microenvironment, miR-145 and miR-199a are exclusively expressed in tumor-associated stroma (TAS) cells, but these miRNAs are present in PDAC cells following co-culture with TAS cells. We hypothesized that miRNAs function as paracrine signals via exosomal exchange between TAS cells and adjacent PDAC cells. Primary cultures of human TAS and PDAC cells were employed. Membrane-bound microparticles were isolated from TAS conditioned, serum-free culture media by sequential ultracentrifugation followed by ultrafiltration. Exosomes and microvesicles were then assayed for particle size distribution using nanoparticle tracking analysis and electronic microscopy. miRNA expression levels were determined using quantitative PCR. miRNA transfection was performed with RNAiMax reagents. Cell viability was measured by Alamar Blue. Statistics were performed using Prism 6 software. Following transfection of human TAS cells with cel-miR-39, a nonhuman miRNA, we demonstrated that miRNA exchanges occurred between TAS cells and neighboring PDAC cells via a process that is not dependent upon cell-cell contact. We next confirmed the presence and enrichment of miR-145-5p in TAS-cell-derived exosomes (8-fold higher concentrations in exosomes than parental cells, p Taken together, our data suggest that stroma derived exosomes deliver miRNAs to adjacent PDAC cells and may function as tumor-suppressing paracrine signals in the case of miR-145. This finding provides a potential explanation for the observation that stroma depletion paradoxically accelerates PDAC progression in murine models. Citation Format: Song Han, Sayali Belsare, DongYu Zhang, Mark Beveridge, Carlos Rinaldi, Jose G. Trevino, Thomas D. Schmittgen, Steven J. Hughes. Exosomal delivery of stroma-derived miR-145 inhibits pancreatic cancer cell proliferation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4322. doi:10.1158/1538-7445.AM2017-4322

Introduction: Pancreatic cancer (PC) is associated with a high rate of cachexia, which specifically diminishes quality of life, prohibits effective therapies, and subsequently contributes to morbidity and mortality. Unfortunately, mechanisms underlying this cancer-induced muscle wasting in the human disease remain incompletely described, in part due to limited translational models. Therefore, we hypothesize that the development of more representative models of PC cachexia will allow for development of therapeutic targets for cachexia. To test our hypothesis, we propose to 1) establish the first patient-derived xenograft (PDX) cancer cachexia models to identify the muscle associated with PC induced cachexia and 2) support these results by examining the corresponding skeletal muscle of PC patients whom contributed to the PDX models. Methods: Rectus abdominis muscle was biopsied from surgically resected PC patients and matched non-cancer controls. After surgical harvest of PC specimen, PDX models were derived in NOD.Cg-PrkdcscidIl2rgtm1Wjl/SzJ (NSG) mice and skeletal muscle was subsequently harvested for histologic investigations on ultrastructural disorganization and qRT-PCR for atrophy-related transcription factors differentially regulated in PC patients. Systemic cytokine expression profiles were analyzed with luminex technology and confirmed by ELISA. Results: Rectus biopsies from patients with resected PC displayed marked muscle fiber atrophy, increased extracellular space, greater variation in fiber size and shape and more centralized nuclei compared to controls. These architectural abnormalities were also present in mice bearing xenografts from corresponding PC patients. Despite the absence of an adaptive immune system, PDX mice demonstrated high levels of systemic TNFα, IL-1β, IL6 and KC (IL8) with a concomitant decrease in anti-inflammatory cytokine IL10 when compared to matched controls. Further, skeletal muscle from both patients with PC and mice bearing PDX tumors demonstrated increased expression of the Forkhead boxO1 (FoxO1) transcription factor and FoxO target gene and E3 ubiquitin ligase, MuRF1, both of which have been directly implicated in the regulation of muscle mass. Conclusions: Preoperative muscle wasting in PC is associated with characteristic architectural abnormalities and elevated FoxO1-MuRF1 levels. Mice bearing PDX demonstrate comparable elevations in circulating pro-inflammatory cytokines, muscle pathology and FoxO1-MuRF1 levels. These results provide a valid translational model of cachexia which suggests a central role for FoxO1 and MuRF1 in PC-associated muscle wasting. Citation Format: Daniel Delitto, Sarah M. Judge, Rachel L. Nosacka, Andrea Knowlton, Fernanda G. Rocha, Kevin E. Behrns, Steven J. Hughes, Shannon M. Wallet, Andrew R. Judge, Jose G. Treviño. Pro-inflammatory cytokine secretion and gene networks associate with pancreatic cancer induced cachexia. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 1017.

Background: The systemic treatment of pancreatic cancer (PC) is hindered by the rapid development of chemoresistance to current cytotoxic therapies. Mechanisms governing the development of chemoresistance remain poorly characterized, particularly with respect to contributions from the tumor microenvironment. Thus, the goal of this study was to identify novel mechanisms acting within the tumor microenvironment which lead to PC chemoresistance. Methods: Intratumoral soluble mediator concentrations from resected PC specimens (n = 26) as well as supernatants from co-cultures of primary tumor-associated pancreatic stellate cells (PSCs) and PC cells (n = 12) were evaluated using a panel of 41 growth factors, chemokines and cytokines. The effect of CXCL10, a highly expressed soluble mediator during co-culture, on viability, proliferation, and apoptosis of PC cells was evaluated with and without gemcitabine treatment. In addition, the contribution of CXCL10 on migration patterns of peripheral blood mononuclear cells (PBMCs) was assessed. Results: Co-culture of tumor-associated PSCs with PC cells revealed increased CXCL10 levels compared to either cell type cultured alone. In addition, high intratumoral CXCL10 concentrations correlated with reduced overall survival (HR 6.9; P = .006). While CXCL10 treatment had a small effect on the viability of PC cells, it led to significantly increased PC cell viability in the presence of gemcitabine. Further, gemcitabine treatment induced the expression of the CXCL10 receptor, CXCR3, and this induction of CXCR3 was associated with the absence of apoptotic markers in PC cells. Finally, constitutive expression of CXCL10 by PC cells preferentially led to the migration of regulatory immune cell subsets. Conclusion: Paracrine CXCL10 signaling between stromal, PC and immune cells may be responsible not only for chemoresistance to gemcitabine, but also the recruitment and potential polarization of regulatory immune cell subsets in the pancreatic cancer microenvironment. Citation Format: Daniel Delitto, Chelsey Perez, Brian S. Black, Heather L. Sorenson, Andrea E. Knowlton, Song Han, Dongyu Zhang, George A. Sarosi, Lyle L. Moldawer, Kevin E. Behrns, Chen Liu, Thomas J. George, Ryan M. Thomas, Jose G. Trevino, Shannon M. Wallet, Steven J. Hughes. CXCL10 within the tumor microenvironment induces gemcitabine resistance in pancreatic cancer cells. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 5028. doi:10.1158/1538-7445.AM2015-5028

Smoking is an established risk factor for the development of pancreatic adenocarcinoma (PC). However, the relationship between smoking and PC tumor biology is incompletely defined. We report reduced overall survival (OS) in PC patients who continued smoking after surgical resection with curative intention (HR 1.93; P = .040). We further demonstrate augmented paracrine signaling via the hepatocyte growth factor (HGF)/c-Met pathway as a result of nicotine exposure in the PC microenvironment. Specifically, HGF, secreted by patient-derived PC tumor associated stroma (TAS), activates the c-Met receptor in PC cells. This paracrine activation subsequently leads to downstream induction of inhibitor of differentiation-1 (Id1) in PC cells, previously established as a mediator of chemoresistance. Further delineation of the signaling pathway demonstrates HGF-induced Id1 expression is abrogated by silencing of c-Met or pharmacologic inhibition. In patient-derived PC xenografts, nicotine treatment augmented tumor growth and metastasis; tumor lysates from nicotine-treated mice demonstrated elevated HGF expression and phospho-Met levels. Additionally, patients with high intratumoral phospho-Met levels exhibited reduced overall survival compared to those with low phospho-Met levels (Median OS 6.1 vs. 15.2 months, respectively; P = .028). Taken together, our data reveal that nicotine promotes the progression of PC via a microenvironment-dependent, paracrine signaling mechanism. Citation Format: Daniel Delitto, Dongyu Zhang, Song Han, Brian S. Black, Andrea E. Knowlton, Adrian C. Vlada, George A. Sarosi, Kevin E. Behrns, Ryan M. Thomas, Xiaomin Lu, Chen Liu, Thomas J. George, Steven J. Hughes, Shannon M. Wallet, Jose G. Trevino. Nicotine reduces survival via augmentation of paracrine HGF-MET signaling in the pancreatic cancer microenvironment. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 470. doi:10.1158/1538-7445.AM2015-470

Direct implantation of viable surgical specimens provides a representative preclinical platform in pancreatic adenocarcinoma (PC). Patient-derived xenografts consistently demonstrate retained tumor morphology and genetic stability. However, the evolution of the tumor microenvironment over time remains poorly characterized in these models. This work specifically addresses the recruitment and incorporation of murine stromal elements into expanding patient-derived PC xenografts, establishing the rapidity by which murine cells are integrated into networks of invading cancer cells. In addition, we provide methodology and observations in the establishment and maintenance of a patient-derived PC xenograft model. A total of 25 histologically confirmed pancreatic adenocarcinoma specimens were implanted subcutaneously into NOD-SCID mice. Patient demographics, staging, pathologic analysis and outcomes were analyzed. After successful engraftment of tumors, histologic and immunofluorescent analyses were performed on explanted tumors. PC specimens were successfully engrafted in 15 of 25 (60%) of attempts. Successful engraftment does not appear to correlate with clinicopathologic factors or patient survival. Tumor morphology is conserved through multiple passages and tumors retain metastatic potential. Interestingly, despite morphologic similarity between passages, human stromal elements do not appear to expand with invading cancer cells. Rather, desmoplastic murine stroma dominates the xenograft microenvironment after the initial implantation. Recruitment of stromal elements in this manner to support and maintain tumor growth represents a novel avenue for investigation into tumor-stromal interactions. Citation Format: Daniel Delitto, Kien Pham, Adrian C. Vlada, George A. Sarosi, Ryan M. Thomas, Kevin E. Behrns, Chen Liu, Steven J. Hughes, Shannon M. Wallet, Jose G. Trevino. Patient-derived xenograft models for pancreatic adenocarcinoma demonstrate retention of tumor morphology through the incorporation of murine stromal elements. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 1466. doi:10.1158/1538-7445.AM2015-1466

Introduction: Inhibitor of differentiation-1 (Id1) demonstrates a role in tumor progression in a variety of tumors but scarce data exists for pancreatic adenocarcinoma. Previously, we demonstrated that nicotine, the addicting component of tobacco, induces Id1 expression through a Src-dependent signaling pathway promoting proliferation, invasion, and chemoresistance in pancreatic cancer cells. Conversely, silencing of Id1 re-establishes gemcitabine sensitivity in acquired and innate gemcitabine-resistant cell lines. Therefore, we determined the role of Id1 in tumor progression and chemoresistance in vivo and determined the expression status of Id1 in a large cohort of human pancreatic cancer tissues. Methods: Cell lysate analyses (protein analyses, mRNA expression) were determined in a bio-diverse sample of pancreatic cancer cells by western and RT-PCR. Metastatic pancreatic cancer cells were stably transfected with a luciferase expression vector and stable short-hairpin RNA silencing of Id1 gene expression with controls. Orthotopic nude mouse model utilized intraperitoneal injections of nicotine (1mg/kg, M/W/F) and gemcitabine (250 mg/kg, T/Th) with monitoring of in vivo growth and metastases based on luminescent signal concentration. Confirmation of primary tumor and metastases was confirmed by H&E staining. Tissue microarrays (TMAs) constructed from 100 resected pancreatic adenocarcinoma were stained for Id1, phospho-Src, and total Src using immunohistochemistry techniques. Scores based on intensity, percent of positive cells, and pathological grade (1-4) were assigned to each malignant core. Results: In vivo, nicotine significantly promoted tumor growth and metastases in vivo. While gemcitabine reduced the tumor burden in control mice, nicotine abrogates this inhibitory effect. Additionally, knockdown of Id1 results in a significant decrease in tumor burden with no identifiable liver metastases, regardless of nicotine exposure. Analyses of resected pancreatic tumor TMAs demonstrated a statistically significant correlation between Id1 and tumor grade/differentiation (p =0.0368). The correlation of protein levels of Id1 and phospho-Src was also statistically significant (p =0.0024); Comparison of overall survival and tumor grade was also significant (p = 0.05); the correlation between overall-survival and Id1 expression trended toward statistical significance (p =0.06). Conclusions: Id1, through a Src-dependent-Id1 signaling axis, promotes tumorigenesis and chemoresistance in an in vivo pancreatic cancer model. Id1 expression correlates with phospho-Src levels and tumor differentiation in human pancreatic cancer tissues. These results support the clinical assessment of Id1 expression as a biomarker of prognosis and support investigations toward targeted therapies against Id1 for pancreatic cancer patients. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 798. doi:1538-7445.AM2012-798