Metabolic abnormalities in the bone marrow cells of young offspring born to obese mothers

Intrauterine metabolic reprogramming occurs in obese mothers during gestation, putting the offspring at high risk of developing obesity and associated metabolic disorders even before birth. We have generated a mouse model of maternal high-fat diet-induced obesity that recapitulates the metabolic changes seen in humans born to obese women. Here, we profiled and compared the metabolic characteristics of bone marrow cells of newly weaned 3-week-old offspring of dams fed either a high-fat (Off-HFD) or a regular diet (Off-RD). We utilized a state-of-the-art targeted metabolomics approach coupled with a Seahorse metabolic analyzer. We revealed significant metabolic perturbation in the offspring of HFD-fed vs. RD-fed dams, including utilization of glucose primarily via oxidative phosphorylation. We also found a reduction in levels of amino acids, a phenomenon previously linked to bone marrow aging. Using flow cytometry, we identified a unique B cell population expressing CD19 and CD11b in the bone marrow of three-week-old offspring of high-fat diet-fed mothers, and found increased expression of Cyclooxygenase-2 (COX-2) on myeloid CD11b, and on CD11bhi B cells. Altogether, we demonstrate that the offspring of obese mothers show metabolic and immune changes in the bone marrow at a very young age and prior to any symptomatic metabolic disease.

Abstract 2276: Spatiotemporal analysis of metastatic melanoma reveals mechanisms of resistance to immune checkpoint blockade

The treatment of metastatic melanoma has been revolutionized with the introduction of immune checkpoint blockade (ICB) therapies in the last decade. Despite durable responses exhibited by a subgroup of patients, most of patients do not respond to ICB therapies and the vast majority (60%-90%) of patients experience disease progression within five years. Molecular mechanisms of primary and acquired resistance to ICB are still widely unknown, which warrants further mechanistic investigation. Towards that goal, we used a holistic approach driven by integrated genomic tools to molecularly profile 35 longitudinal tumor specimens at pre-, on-, and post-treatment time points which were derived from seven patients with metastatic melanoma who progressed on sequential ICB therapies, including three responders and four non-responders. We integrated analyses of data generated from RNA sequencing, Whole-exome Sequencing (WES), NanoString nCounter vantage 3D, Cyclic Immunofluorescence (CyCIF), NanoString Digital Spatial Profiling (DSP) and Multiplex Immunohistochemistry (mIHC) platforms to elucidate evolutionary trajectories that occurred in both the tumor and the tumor immune microenvironment (TiME) that may have orchestrated response and resistance to ICB therapies. Simultaneous analyses conducted on genomic, transcriptomic and proteomic levels identified the re-activation of the MAPK pathway as a potential mechanism of resistance to ICB therapies. Spatially-resolved, image-based immune monitoring analysis at single cell resolution revealed that response to ICB is associated with infiltration of immune cells accompanied by induced activities of myeloid, T cells and macrophages in the TiME. In summary, integrated analyses allow us not only to reveal the dynamic co-revolution of both tumor and immune cells in TiME following sequential ICB therapies but also to provide a comprehensive perspective to molecular mechanisms of response and resistance to ICB therapies. A deeper understanding and elucidation of the evolution of mechanisms of response and resistance to ICB therapies will point us to generate hypothesis-driven, potential salvage therapies to overcome resistance to ICB therapies.

Citation Format: Shiyou Wei, Jinho Lee, Marilyne Labrie, Courtney Betts, Lunxu Liu, Lisa Coussens, Meenhard Herlyn, Genevieve Boland, Gordon Mills, Gao Zhang. Spatiotemporal analysis of metastatic melanoma reveals mechanisms of resistance to immune checkpoint blockade [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2276.

Abstract 3247: Combination therapy using PERK and PD1/PD-L1 inhibitors reprograms tumor associated macrophages and reduces tumor burden

Background: The role of endoplasmic reticulum (ER) stress is profound in increasing malignant activity of neoplastic tumor cells and has been recently demonstrated to also increase immunosuppressive activity of tumor-associated macrophages (TAMs). Immunosuppressive TAM activity is thought to underly resistance to PD-1/PD-L1-targeted immune checkpoint inhibitors used for cancer therapy. Protein kinase RNA-like endoplasmic reticulum kinase (PERK) is a rate-limiting enzyme central to the ER-stress response mechanism that transduces ER-stress signals in cells to regulate protein synthesis, cell death, and cell survival. We hypothesized that inhibition of PERK would improve responses to ICI therapy by reprogramming TAM from immunosuppressive to immunoactivating cells.

Methods: To investigate if ER-stress underlies resistance to PD-1/PD-L1 targeted therapies, we utilized ex vivo assays to investigate ER-stress regulation of macrophage phenotype, and in vivo syngeneic murine models of melanoma growth, with HC-5404 (PERKi), a selective and potent first-in-human small molecule PERK inhibitor currently in a phase 1 clinical trial for solid tumors (NCT04834778).

Results: Treatment with PERKi sensitized αPD-1/PD-L1 mAb-resistant melanoma tumors (Y1.7/YR1.7) to PD-1/PD-L1 blockade with concomitant increase in tumor infiltrating leukocytes, TH1- reprogrammed TAM, and cytotoxic CD8+ T cells. In addition to tumor microenvironment changes by PERKi, gene expression analysis confirmed reprograming of the tumor microenvironment, marked by a relative increase in TH1-associated genes and downregulation of TH2-associated genes when compared with untreated tumors. We utilized an ex vivo macrophage-splenocyte co-culture assay to depict macrophage dependent T cell suppression prevalent in tumors. This revealed that treating macrophages with PERKi prior to co-culturing with T cells or adding PERKi to the macrophage-T cell co-culture relieved macrophage dependent T cell suppression, illustrating a potential mechanism of therapeutic efficacy. We are now studying how ER-stress is regulated in TAMs and are focusing on identifying components of PERK-dependent cell signaling that increases the tumor promoting behavior of TAMs.

Conclusions: The combination therapy targeting PERK and PD-1/PD-L1 signaling increased adaptive immune responses, reprogramed TAMs and reduced tumor growth kinetics. Results from these studies highlight a role for ER-stress signaling in TAMs to maintain an immunosuppressive tumor microenvironment and demonstrate the potential therapeutic strategy of PERK inhibition in αPD-1/PD-L1 resistant tumors.

Citation Format: Sushil Kumar, Michael McCane, Jeremy Drees, Nandita Bose, Lisa Coussens. Combination therapy using PERK and PD1/PD-L1 inhibitors reprograms tumor associated macrophages and reduces tumor burden [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3247.

Abstract PO-095: A cancer cell-intrinsic GOT2-PPARδ axis suppresses antitumor immunity

Glutamic-oxaloacetic transaminase 2 (GOT2) encodes a product with dual functions: primarily as a metabolic enzyme in mitochondria but also as a putative fatty acid (FA) binding protein. The purpose of this study is to investigate GOT2 function and FA-binding in PDA carcinogenesis. Depletion of GOT2 expression with CRISPR-Cas9 or shRNA in human and murine PDA cell lines shows no proliferation defects in vitro. However, GOT2-depleted cells orthotopically implanted in immunocompetent hosts fail to form large tumors. Analysis of cancer cell proliferation shows no difference between control and knockout (KO) tumors, indicating proliferation is not affected by GOT2 in vivo. Genes negatively correlated with GOT2 expression in human PDA reveal ontology clusters associated with adaptive immune response, which suggests an immune-modulatory role of GOT2. Quantitation of immune markers using conventional and multiplex immunohistochemistry confirmed enhanced immune cell infiltration in KO tumors. Inhibition of T cells with blocking antibodies rescued the growth of GOT2 KO tumors, further validating the role of GOT2 in mediating adaptive tumor immunity. In addition to its known mitochondrial and plasma membrane localization, GOT2 expression was observed in the nuclei of PDA cells. It was hypothesized that nuclear GOT2 can deliver FA-ligand to activate PPARs (peroxisome proliferator activator receptor), a class of ligand-activated transcription factors with tumor-promoting properties; specifically, the ubiquitously expressed PPARδ. Analysis of human PDA RNA-seq data shows a significant positive correlation between GOT2 and PPARδ target genes. GOT2-dependent PPARδ activation in PDA cells was confirmed in vitro. Computational modeling of the crystal structure of GOT2 revealed a suitable arachidonic acid (AA) docking site, a known PPARδ ligand. Lipid binding assays of purified protein confirmed direct GOT2-AA binding. The FA docking site of GOT2 was mutated and KO cells were reconstituted with wild type and mutant GOT2. GOT2 mutant cells, compared to wild-type GOT2 cells, showed reduced PPARδ activity, nuclear localization, and interaction with PPARδ. In vivo, mutant GOT2 increased immune cell infiltration. Lastly, the rescue of PPARδ activity in GOT2 KO tumors restores the formation of large tumors with similar immune microenvironments to control tumors. We conclude that the enzymatic function of GOT2 is dispensable for PDA proliferation. However, GOT2 direct FA binding enhances activation of PPARδ to promote an immune-suppressed microenvironment. This non-canonical function of GOT2 can be further explored to elucidate mechanisms of immune evasion in PDA and aid in the development of efficient immunotherapies to improve disease outcomes.

Citation Format: Jaime Abrego, Hannah Sanford-Crane, Chet Oon, Xu Xiao, Courtney Betts, Duanchen Sun, Shanthi Nagarajan, Zheng Xia, Lisa Coussens, Peter Tontonoz, Mara Sherman. A cancer cell-intrinsic GOT2-PPARδ axis suppresses antitumor immunity [abstract]. In: Proceedings of the AACR Virtual Special Conference on Pancreatic Cancer; 2021 Sep 29-30. Philadelphia (PA): AACR; Cancer Res 2021;81(22 Suppl):Abstract nr PO-095.

Feasibility of real-time serial comprehensive tumor analytics: Pilot study of olaparib and durvalumab in metastatic triple negative breast cancer (mTNBC)

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Background: Longitudinal analysis of serial tumor biopsies is an under-utilized approach to studying adaptive mechanisms of resistance. We have established a comprehensive analytic platform to evaluate real-time trial sample analysis to inform precision oncology combinations in mTNBC. The primary endpoint of the study is feasibility of completing all CLIA assays within 28 days of biopsy. Methods: Following a pre-treatment biopsy and 4 weeks of olaparib monotherapy mTNBC patients underwent an on-treatment (tx) biopsy and durvalumab was added to their therapy. Pre- and on-tx biopsies underwent comparative analysis using CLIA assays (immunohistochemistry-IHC, whole exome seq, RNAseq and phospho-proteomics) as well as research assays (multiplex IHC-mIHC, cyclic immunofluorescence-IF, and reverse phase protein array-RPPA). Results: Serial biopsies were obtained from all 3 enrolled patients, and the primary endpoint was achieved for all patients (Table). Treatment was well tolerated, and 2 patients achieved clinical benefit > 6 months. In one patient with a prolonged CR ( > 18 months), the on-tx sample exhibited dramatic changes in protein network rewiring by protein data analysis (RPPA, cyclic-IF), and an increase in immune infiltrate by mIHC. Conclusions: This pilot confirmed the feasibility of rapid real-time analysis to inform treatment decisions. This led to the development and initiation of biomarker driven olaparib combination trials in mTNBC at our institution. Clinical trial information: NCT03544125 . [Table: see text]

Abstract 1558: Therapeutic targeting of cell surface plectin induces anti-cancer immune response and pancreatic cancer regression

Background: Pancreatic ductal adenocarcinoma (PDA) is the 3rd deadliest cancer, diagnosed typically in advanced stages, with only an 8% 5-year survival rate, thus demonstrating the need for novel therapeutic approaches that significantly enhance chemo- and/or immune-therapy. Our team previously identified a promising functional target for cancer therapy in PDA, cell surface plectin 1 (CSP1) that is aberrantly expressed on PDA cells and thus a cell surface-associated biomarker of cancer. CSP1 expression first becomes apparent in high grade dysplasias, remaining high in early and advanced cancers and in metastases. Our first-in-human imaging trial in PDA patients using a CSP1-targeted imaging agent revealed that CSP is an available target and accessible for binding, a potentially a target for cancer therapy. We hypothesized that a monoclonal antibody (mAb) against CSP1 could lead to novel pancreatic cancer treatment options, thus, we developed a therapeutic mAb, e.g., ZB131, representing a first-in-class antibody selectively targeting CSP1.

Methods: ZB131 is a humanized mAb targeted against human plectin 1 (rhSec8) that also binds murine CSP1. ZB131 affinity and its effect on cancer cells including proliferation, cytotoxicity, and migration were tested in vitro using saturation binding, SRB-based survival assays, flow cytometry, and migration assays on various pancreatic cell types and homeostatic “normal” controls. In vivo validation was performed using two nu/nu mouse models bearing subcutaneous MiaPACA2 or Yapc PDA cells, and a syngeneic KPC-derived tumor model to also evaluate immune responses to tumors treated with ZB131 or IgG control.

Results: ZB131 exhibits high specificity and high affinity (0.4±0.1nM) to CSP1, and functionally induces G0 growth arrest followed by necrotic cell death of PDA cells in culture, and is synergistic with gemcitabine resulting in a 50-fold decrease in IC50. In vivo, in subcutaneous xenograft models, ZB131 monotherapy decreased PDA tumor volume 5-fold as compared to controls, and in combination with cisplatin resulted in sustained tumor reduction with greater than 85% tumor necrosis. In subcutaneous syngeneic PDA models, ZB131 induced complete tumor regression within 35 days mediated by an anti-tumor immune response as upon tumor rechallenge, full tumor regression was again achieved without additional ZB131 therapy. Leukocyte complexity analysis of regressing PDA tumors versus controls revealed an ~3-fold increase in effector and central memory T cells.

Conclusion: CSP1 is a first in class anti-cancer target expressed on the cell surface of PDA, as well as other cancers including ovarian, esophageal and head neck. ZB131, an anti-CSP1 mAb, induces tumor cell intrinsic cell death, as well as a robust anti-tumor T cell response leading to complete tumor regression indicating the potential therapeutic efficacy of ZB131 in late-stage cancers.

Citation Format: Julien Dimastromatteo, Amanda Poisonnier, Samantha Perez, Lisa Coussens, Kimberly Kelly. Therapeutic targeting of cell surface plectin induces anti-cancer immune response and pancreatic cancer regression [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1558.

Abstract BL1: Modeling Immune Response: Lessons Learned from Mouse Models of Cancer Development

The concept that leukocytes are critical components of solid tumors is now generally accepted, however, their role(s) in regulating aspects of cancer progression, and/or response to cytotoxic, targeted and/or immune therapy is only beginning to be understood. Utilizing de novo mouse models of mammary tumor development, we now appreciate that CD4+ T lymphocytes differentially regulate myeloid cell recruitment, activation and effector function, and in turn, activated tumor-infiltrating myeloid cells foster malignancy and repress anti-tumor immunity by a diversity of mechanisms. Treatment of tumor-bearing mice with therapeutic agents disrupting lymphocyte-myeloid interactions, myeloid activation, or myeloid functionality generally slow primary tumor growth kinetics when combined with cytotoxic therapy; however, their impact on metastases is variable. Similar to organ-specific regulatory programs co-opted to foster primary tumor growth, regulation of metastatic seeding and outgrowth is also regulated by tissue- and organ-specific mechanisms. Based on this, it stands to reason that therapeutic strategies may not be efficacious in both primary and metastatic locations. To be presented will be our recent insights into organ-specific regulation of primary and metastatic mammary cancer development by adaptive and innate immune cells regulating pro- and/or anti-tumor immunity, and new studies evaluating how attenuating protumor properties of select lymphoid and myeloid cells can be exploited to enhance therapeutic responses to cytotoxic and immune-based therapy.

LMC acknowledges generous support from the NIH / NCI, the Department of Defense Breast Cancer Research Program Era of Hope Scholar Expansion Award, Susan G. Komen Foundation, the Breast Cancer Research Foundation, the Brenden-Colson Center for Pancreatic Health, and a Stand Up To Cancer – Lustgarten Foundation Pancreatic Cancer Convergence Dream Team Translational Research Grant.

Citation Format: Coussens L. Modeling Immune Response: Lessons Learned from Mouse Models of Cancer Development [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr BL1.

Targeting myeloid-inflamed tumor with anti-CSF-1R antibody expands CD137+ effector T-cells in the murine model of pancreatic cancer

BACKGROUND

The pancreatic cancer vaccine, GVAX, induces novel lymphoid aggregates in the otherwise immune quiescent pancreatic ductal adenocarcinoma (PDAC). GVAX also upregulates the PD-1/PD-L1 pathway, and a pre-clinical model demonstrated the anti-tumor effects of combination GVAX and anti-PD-1 antibody therapy (GVAX/αPD-1). Resistance to GVAX was associated with an immune-suppressive myeloid cell infiltration, which may limit further therapeutic gains of GVAX/αPD-1 therapy. The expression of CSF-1R, a receptor important for myeloid cell migration, differentiation and survival, and the effect of its therapeutic blockade in the context of GVAX in PDAC has not been investigated.

METHODS

Lymphoid aggregates appreciated in 24 surgically resected PDAC from patients who received one dose of neoadjuvant GVAX were analyzed with multiplex immunohistochemistry. Flow cytometry analysis of tumor infiltrating T-cells in a murine model of PDAC was performed to investigate the therapeutic effects and mechanism of anti-CSF-1R/anti-PD-1/GVAX combination immunotherapy.

RESULTS

High CSF-1R expression in resected PDAC from patients who received neoadjuvant GVAX was associated with a higher myeloid to lymphoid cell ratio (p < 0.05), which has been associated with poorer survival. This higher CSF-1R expression was associated with a higher intra-tumoral infiltration of immature dendritic cells (p < 0.05), but not mature dendritic cells (p = 0.132). In the pre-clinical murine model, administering anti-CSF-1R antibody prior to and after GVAX/αPD-1 ("pre/post-αCSF-1R + αPD-1 + GVAX") enhanced the survival rate compared to GVAX/αPD-1 dual therapy (p = 0.005), but administering anti-CSF-1R only before GVAX/αPD-1 did not (p = 0.41). The "pre/post-αCSF-1R + αPD-1 + GVAX" group also had higher intra-tumoral infiltration of PD-1 + CD8+ and PD-1 + CD4+ T-cells compared to αPD-1/GVAX (p < 0.001). Furthermore, this regimen increased the intra-tumoral infiltration of PD-1 + CD137 + CD8+, PD-1 + CD137 + CD4+ and PD-1 + OX40 + CD4+ T-cells (p < 0.001). These PD-1 + CD137 + CD8+ T-cells expressed high levels of interferon-γ (median 80-90%) in response to stimulation with CD3/CD28 activation beads, and this expression was higher than that of PD-1 + CD137-CD8+ T-cells (p < 0.001).

CONCLUSIONS

The conversion of exhausted PD-1+ T-cells to CD137+ activated effector T-cells may contribute to the anti-tumor effects of the anti-CSF-1R/anti-PD-1/GVAX combination therapy. Anti-CSF-1R antibody with anti-PD-1 antibody and GVAX have the potential be an effective therapeutic strategy for treatment of PDAC.

Abstract 3296: SMMART: Serial measurements of molecular and architectural responses to therapy

SMMART is a precision medicine research program focused on understanding the evolution of actionable biology and mechanisms of resistance in human tumors during therapy. This is accomplished through in depth functional, ‘omic and multiscale image analysis of longitudinal samples acquired during treatment. Here we present a case report detailing the insights that can be gained from the comparative analysis of pre- and post-treatment biopsy specimens in a late-stage metastatic breast cancer patient. To understand the molecular evolution of cancer, we interrogated genomics with targeted and whole exome sequencing, transcriptomics with RNA and gene-fusion sequencing, and proteomics with reverse phase protein arrays. To understand cellular organization and architectural changes, we employed multi-scale imaging tools, including scanning electron microscopy (SEM), cyclic immunofluorescence, immune cell profiling with cyclic immunohistochemistry, and traditional pathological assessment. During the course of treatment, we monitored patient response to therapy with clinical imaging, circulating tumor DNA sequencing and cancer protein assessment.

Individual assays revealed key aspects of how this individual's cancer evolved under therapeutic pressure. For example, mutational profiling revealed the patterns of clonal evolution and the acquisition of new genetic driver events. 2D and 3D SEM showed changes in ECM organization, macropinocytosis, mitochondrion size, number and density and number and organization of filopodia-like protrusions. We used a 30-color cyclic immunofluorescence analysis to identify differences in cancer cell proliferation and differentiation state, as well as the composition and organization of infiltrating immune cells. In addition, integrative analyses of multiple data types provided insight into the evolution of actionable biology within this patient's disease. This included changes in the suitability of the patient for immune checkpoint inhibitors as well as specific tyrosine kinase inhibitors. The comprehensive molecular and architectural characterization of an individual patient's cancer at multiple time points provides biologically novel and clinically relevant insight into the ways in which cancers become resistant to treatment.

Citation Format: Brett Johnson, Jamie Keck, Max Morris, Kiara Siex, Annette Kolodzie, Swapnil Parmar, Jessica Riesterer, Koei Chin, Summer Gibbs, Laura Heiser, Paul Spellman, Kyle Ellrott, Ozgun Babur, Emek Demir, Adam Margolin, Jeremy Goecks, Lisa Coussens, Raymond Bergan, Joe Gray. SMMART: Serial measurements of molecular and architectural responses to therapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3296.

Abstract B118: Developing a molecular and cellular atlas of pancreatic disease

Experimental results generated from human pancreatic ductal adenocarcinoma (PDAC) specimens have produced a broad knowledge of pancreatic tumors. However, successful personalized treatment of pancreatic disease will require an exceptionally deep knowledge of the molecular and cellular diversity of tumors, as well as their evolution through the course of disease progression, therapeutics, relapse, and terminal disease burden. To address this need, we have conducted diverse but complementary experimental analyses on adjacent regions of fresh tumor specimens collected from over 70 primary pancreas specimens obtained during Whipple and RAMPS procedures. Coordination between surgical and research teams has ensured that only a minimum time elapses between surgical resection and specimen processing, thus limiting potential degradation by pancreatic enzymes. Researchers with diverse cancer biology expertise obtain adjacent dissections from three regions (i.e., tumor, dysplastic, and normal) within each pancreas specimen. An annotated image of the whole pancreas specimen records the location of each dissected portion relative to one another. Fresh tissues are immediately used to 1) characterize the phenotypic diversity of tumor and non-tumor cells in the microenvironment, 2) isolate and culture cancer stem cells, 3) perform high resolution imaging including 3D-SEM, 4) “bioprint” and culture three-dimensional, multi-cell-type structures, and 5) propagate tumors in mouse avatars. Genomics, epigenomics, and transcriptomics analyses are also performed on laser-captured specimens. In addition to primary PDAC tumors, other fresh pancreatic cancer specimens are being added to the collection including core needle biopsies obtained from treatment-naïve patients, metastases removed during primary tumor resection or recurrence, and tumor specimens from a rapid autopsy program. Importantly, all specimens are fully clinically annotated as patients are followed through the course of their disease.

By comprehensively characterizing individual pancreatic tumors from many patients we hope to produce a unique body of information – an “Atlas” of pancreatic disease – that will inform the research community of new molecular and cellular features that contribute to the progression and therapeutic resistance of this devastating disease. Research data and clinical information in the Atlas will be accessible through a user-friendly customizable database. We hope that this resource will support the development of molecularly targeted early detection, therapeutics, and prevention in order to improve patient care. Funding for this initiative comes from philanthropic support to the Brenden-Colson Center for Pancreatic Care at Oregon Health and Science University.

Citation Format: Jason M. Link, Brittany Allen-Petersen, Andrew Gunderson, Danielle Jorgens, Craig Dorrell, Jody Hooper, Philip Streeter, Markus Grompe, Lisa Coussens, Joe Gray, Hope Hardaker, Charles D. Lopez, Rosalie C. Sears, Brett C. Sheppard. Developing a molecular and cellular atlas of pancreatic disease. [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer: Innovations in Research and Treatment; May 18-21, 2014; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2015;75(13 Suppl):Abstract nr B118.

Sustained endothelial expression of HoxA5 in vivo impairs pathological angiogenesis and tumor progression

HoxA5 is expressed in quiescent endothelial cells (EC), but absent in activated angiogenic EC. To examine the efficacy of targeting HoxA5 therapeutically to quell pathologic or tumor angiogenesis, we generated an inducible, transgenic mouse model of sustained HoxA5 expression in ECs. During pathologic angiogenesis, sustained HoxA5 regulates expression several angiogenic effector molecules, notably increased expression of TSP-2 and reduced expression of VEGF, thus leading to inhibition of pathological angiogenesis in tissues. To evaluate if this impressive reduction of vascularization could also impact tumor angiogenesis, HoxA5 mice were bred with a mouse model of de novo squamous carcinogenesis, e.g., K14-HPV16 mice. Activation of EC-HoxA5 significantly reduced infiltration by mast cells into neoplastic skin, an early hallmark of progression to dysplasia, reduced angiogenic vasculature, and blunted characteristics of tumor progression. To evaluate HoxA5 as a therapeutic, topical application of a HoxA5 transgene onto early neoplastic skin of K14-HPV16 mice similarly resulted in a significant impairment of angiogenic vasculature and progression to dysplasia to a similar extent as observed with genetic delivery of HoxA5. Together these data indicate that HoxA5 represents a novel molecule for restricting pathological and tumorigenic angiogenesis.

Classification of current anticancer immunotherapies

During the past decades, anticancer immunotherapy has evolved from a promising therapeutic option to a robust clinical reality. Many immunotherapeutic regimens are now approved by the US Food and Drug Administration and the European Medicines Agency for use in cancer patients, and many others are being investigated as standalone therapeutic interventions or combined with conventional treatments in clinical studies. Immunotherapies may be subdivided into "passive" and "active" based on their ability to engage the host immune system against cancer. Since the anticancer activity of most passive immunotherapeutics (including tumor-targeting monoclonal antibodies) also relies on the host immune system, this classification does not properly reflect the complexity of the drug-host-tumor interaction. Alternatively, anticancer immunotherapeutics can be classified according to their antigen specificity. While some immunotherapies specifically target one (or a few) defined tumor-associated antigen(s), others operate in a relatively non-specific manner and boost natural or therapy-elicited anticancer immune responses of unknown and often broad specificity. Here, we propose a critical, integrated classification of anticancer immunotherapies and discuss the clinical relevance of these approaches.

Abstract 489: Prevention of pancreatic intra-epithelial neoplasm progression by a Listeria monocytogenes vaccine targeting mutated Kras, an early genetic event in pancreatic tumor development

Human pancreatic ductal adenocarcinoma (PDA) remains a fatal and highly treatment-resistant disease, characterized by an intense desmoplastic reaction to the tumor. Genetically-engineered mouse models of spontaneously developing PDA mimic the multistep progression from pre-cancer to invasive cancer in humans, and are ideal for studying the tumor microenvironment. The KrasG12D/+; Trp53R172H/+; Pdx-1-Cre mouse model of pancreatic ductal adenocarcinoma combines a Kras dominant active mutation with a p53 loss of function mutation, specifically expressed in the pancreas under the control of the Pdx-1 promoter. Mice begin developing PanINs at several weeks old, progressing to PDA and accompanied by the characteristic desmoplastic reaction seen in human PDA. We evaluated the effect of an attenuated Listeria monocytogenes expressing mutated Kras (LM-Kras) vaccine capable of inducing a Kras-specific T cell response together with regulatory T cell (Treg)-depleting therapy (low dose cyclophosphamide and an anti-CD25 monoclonal antibody) on PanIN progression and survival. Combination immunotherapy given to mice with early stage PanINs increased survival and delayed PanIN progression, whereas intervention in older mice or with single agent immunotherapy failed to alter the course of tumor progression. Local, rather than systemic, changes in T cell activation correlated with delay in PanIN progression. Combination treatment administered during early PanINs correlated with enhanced CD8+ T cell infiltration and activation. In addition, combination treatment induced a Th1/Th17 cytokine expression pattern in CD4+ T cells and decreased infiltration by CD4+Foxp3+ Tregs. Immunohistochemistry revealed granulocytes, myeloid cells, and macrophages infiltrating untreated PanINs and PDA. Analysis of upregulated genes in laser capture micro-dissected specimens of PanINs and invasive PDA included those associated with recruitment of MDSCs, induction of a suppressive phenotype in these cells, and mediators secreted by M2 or N2-type cells. We are further investigating the effect of combination immunotherapy on the granulocyte and myeloid populations with the hypothesis that these signals will be altered with treatment. Thus, vaccination targeting an early genetic event in PDA can slow progression from early PanINs to invasive cancer when Tregs are also altered.

Citation Format: Bridget Keenan, Yvonne Saenger, Michel Kafrouni, Ashley Leubner, Peter Lauer, Anirban Maitra, Andrew Gunderson, Lisa Coussens, Todd Armstrong, Elizabeth Jaffee. Prevention of pancreatic intra-epithelial neoplasm progression by a Listeria monocytogenes vaccine targeting mutated Kras, an early genetic event in pancreatic tumor development. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 489. doi:10.1158/1538-7445.AM2013-489

Abstract 4723: Macrophages foster neoplastic progression of malignant mesothelioma and limit response to chemotherapy

We, and others, have previously reported that macrophages infiltrating mammary adenocarcinomas foster late-stage cancer progression1-3, and that targeted therapies diminishing macrophage presence in tumors, and improve response to standard chemotherapy (CTX) resulting in slowed primary tumor growth, reduced pulmonary metastasis and increased overall survival (OS) of tumor-bearing mice4,5. These experimental studies correlate with clinical findings indicating that high densities of CD68+ myeloid cells correlate with reduced OS in patients with breast cancer6. Malignant mesotheliomas (MM), a rare cancer that can develop as a result of prior asbestos exposure, is highly resistant to conventional cytotoxic therapy7, and in the pleural space is associated with significant densities of macrophages that also correlate with decreased OS8. To investigate a functional role for macrophages in fostering neoplastic progression of MM, and/or in limiting response to CTX, we investigated the efficacy of several antagonists targeting the colony stimulating factor-1 (CSF1)/CSF-1 receptor (CSF1-R) CSF-1R signaling cascade to reveal the functional significance of macrophages in MM, and to determine if this class of agents exhibited efficacy as monotherapy, or in combination with CTX, to improve OS of tumor-bearing mice. Using a syngeneic orthotopic mouse model for MM, our results indicate that reducing the presence of macrophages in MM significantly slows early, as well as late-stage MM growth, and improves response to standard-of-care CTX. These experimental findings indicate a protumoral role for macrophages in MM, and support clinical investigation of targeted therapies, in combination with CTX, for treatment of patients with MM.

1. Lin et al., J Exp Med 193, 727-740 (2001).

2. DeNardo et al., Cancer Cell 16, 91-102 (2009).

3. Gocheva et al., Genes Dev 24, 241-255 (2010).

4. DeNardo et al., Cancer Discov 1, 54-67 (2011).

5. Shree et al., Genes and Development in press(2011).

6. Campbell et al., Breast Cancer Res Treat 128, 703-711 (2011).

7. Sugarbaker et al., Expert Rev Respir Med 4, 363-372 (2010).

8. Burt et al., Cancer 117, 5234-5244 (2011).

The authors acknowledge generous support from the NIH/NCI, Dept of Defense (DoD) Era of Hope Scholar Award Expansion Award, Susan G. Komen Fndt, Breast Cancer Research Fndt, and an Investigator-Initiated Research Award in Mesothelioma from the DoD.

Citation Format: Collin Blakely, Tina Bose, Melissa Wheeler, Raphael Bueno, David Sugarbaker, David Jablons, V. Courtney Broaddus, Lisa Coussens. Macrophages foster neoplastic progression of malignant mesothelioma and limit response to chemotherapy. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 4723. doi:10.1158/1538-7445.AM2013-4723

Q&A: Lisa Coussens on immune reprogramming

We need to embrace the biology of the tumor and recognize that all of the cells in the mass communicate and that they all regulate each other's activity. Unless we can grasp that communication, I think we're missing the boat.

Proteases, extracellular matrix, and cancer: a workshop of the path B study section

The role of the extracellular matrix (ECM) in the tumor microenvironment is not limited to being a barrier against tumor invasion. The ECM is a reservoir of cell binding proteins and growth factors that affect tumor cell behavior. It is also substantially modified by proteases produced by tumor cells or stroma cells. As a result of the activity of these proteases, cell-cell and cell-ECM interactions are altered, new biologically active ECM molecules are generated, and the bioavailability and activity of many growth factors, growth factor receptors, and cytokines are modified. ECM-degrading proteases also play a critical role in angiogenesis, where they can act as positive as well as negative regulators of endothelial cell proliferation and vascular morphogenesis. This review article summarizes some of the most relevant findings made over the recent years that were discussed at a workshop organized by the Path B Study Section of the National Institutes of Health in October 2002.

A functional proteomics screen of proteases in colorectal carcinoma

BACKGROUND

Proteases facilitate several steps in cancer progression. To identify proteases most suitable for drug targeting, actual enzyme activity and not messenger RNA levels or immunoassay of protein is the ideal assay readout.

MATERIALS AND METHODS

An automated microtiter plate assay format was modified to allow detection of all four major classes of proteases in tissue samples. Fifteen sets of colorectal carcinoma biopsies representing primary tumor, adjacent normal colon, and liver metastases were screened for protease activity.

RESULTS

The major proteases detected were matrix metalloproteases (MMP9, MMP2, and MMP1), cathepsin B, cathepsin D, and the mast cell serine proteases, tryptase and chymase. Matrix metalloproteases were expressed at higher levels in the primary tumor than in adjacent normal tissue. The mast cell proteases, in contrast, were at very high levels in adjacent normal tissue, and not detectable in the metastases. Cathepsin B activity was significantly higher in the primary tumor, and highest in the metastases. The major proteases detected by activity assays were then localized in biopsy sections by immunohistochemistry. Mast cell proteases were abundant in adjacent normal tissue, because of infiltration of the lamina propria by mast cells. Matrix metalloproteases were localized to the tumor cells themselves; whereas, cathepsin B was predominantly expressed by macrophages at the leading edge of invading tumors. Although only low levels of urinary plasminogen activator were detected by direct enzyme assay, immunohistochemistry showed abundant protein within the tumor.

CONCLUSIONS

This analysis, surveying all major classes of proteases by assays of activity rather than immunolocalization or in situ hybridization alone, serves to identify proteases whose activity is not completely balanced by endogenous inhibitors and which may be essential for tumor progression. These proteases are logical targets for initial efforts to produce low molecular weight protease inhibitors as potential chemotherapy.

Functionally distinct insulin receptors generated by tissue-specific alternative splicing

Cloning of the insulin receptor cDNA has earlier revealed the existence of two alternative forms of the receptor differing by the presence or absence of 12 amino acids near the C-terminus of the receptor alpha-subunit. This insert has been shown by others to be encoded by a discrete exon, and alternative splicing of this exon leads to tissue-specific expression of two receptor isoforms. We have studied the functional significance of the receptor isoforms and have confirmed that they are generated by alternative splicing. When cDNAs encoding the two forms of the insulin receptors are expressed in Rat 1 cells, the receptor lacking the insert (HIR-A) has a significantly higher affinity for insulin than the receptor with the insert (HIR-B). This difference in affinity is maintained when insulin binding activity is assayed in solution using detergent solubilized, partially purified receptors. These data, combined with the tissue specificity of HIR-A and HIR-B expression, suggest that alternative splicing may result in the modulation of insulin metabolism or responsiveness by different tissues.

Growth hormone stimulates insulin gene expression in cultured human fetal pancreatic islets

The total body mass of the human fetus increases about 100-fold from 10-20 weeks of gestation, and peak serum GH concentrations occur at 20 weeks. Since insulin has an essential growth-promoting influence in the fetus, these experiments were designed to determine whether GH can function as a growth factor with insulin-releasing activity by stimulating insulin gene expression during embryogenesis. Pancreatic islets were isolated from human fetuses (n = 36) of 18-22 weeks gestational age. Insulin gene expression was quantified by measuring insulin mRNA by blot hybridization analysis using a [32P] cDNA probe encoding human insulin. We found that by 48 h of culture insulin gene expression was stimulated by 1.25 micrograms recombinant human GH/mL medium to 216% of the control value (n = 2). Insulin secretory capacity was expressed as a fractional stimulation ratio (FSR = F2/F1) of insulin release rates during two successive 1-h static incubations. After 48 h of culture 1.25 micrograms/mL GH stimulated the FSR value to 273% of the control value (n = 5). We conclude that recombinant human GH significantly enhances the steady state level of insulin mRNA concurrent with an increase in insulin secretory capacity, hence providing evidence for a regulatory function of GH on insulin gene expression during fetal development.

A single receptor binds both insulin-like growth factor II and mannose-6-phosphate

Amino acid sequences deduced from rat complementary DNA clones encoding the insulin-like growth factor II (IGF-II) receptor closely resemble those of the bovine cation-independent mannose-6-phosphate receptor (Man-6-P receptorCI), suggesting they are identical structures. It is also shown that IGF-II receptors are adsorbed by immobilized pentamannosyl-6-phosphate and are specifically eluted with Man-6-P. Furthermore, Man-6-P specifically increases by about two times the apparent affinity of the purified rat placental receptor for 125I-labeled IGF-II. These results indicate that the type II IGF receptor contains cooperative, high-affinity binding sites for both IGF-II and Man-6-P-containing proteins.

Human proto-oncogene c-kit: a new cell surface receptor tyrosine kinase for an unidentified ligand

Structural features of v-kit, the oncogene of HZ4 feline sarcoma virus, suggested that this gene arose by transduction and truncation of cellular sequences. Complementary DNA cloning of the human proto-oncogene coding for a receptor tyrosine kinase confirmed this possibility: c-kit encodes a transmembrane glycoprotein that is structurally related to the receptor for macrophage growth factor (CSF-1) and the receptor for platelet-derived growth factor. The c-kit gene is widely expressed as a single, 5-kb transcript, and it is localized to human chromosome 4 and to mouse chromosome 5. A c-kit peptide antibody permitted the identification of a 145,000 dalton c-kit gene product that is inserted in the cellular plasma membrane and is capable of self-phosphorylation on tyrosine residues in both human glioblastoma cells and transfected mouse fibroblasts. Our results suggest that p145c-kit functions as a cell surface receptor for an as yet unidentified ligand. Furthermore, carboxy- and amino-terminal truncations that occurred during the viral transduction process are likely to have generated the transformation potential of v-kit.

Alternative splicing increases the diversity of the human protein kinase C family

Isolation of two protein kinase C (PKC) cDNA clones containing divergent carboxy-terminal sequences suggested a common genetic origin for these cDNAs. Partial characterization of the hPKC beta chromosomal gene provided direct evidence for the existence of two adjacent carboxy-terminal exons (beta 1 and beta 2) that are alternatively spliced to generate two types of hPKC beta sequences. PKC beta 1 and beta 2 mRNAs are expressed in a selective manner in both human hematopoietic cells and bovine brain tissues.

Multiple, distinct forms of bovine and human protein kinase C suggest diversity in cellular signaling pathways

A new family of protein kinase C-related genes has been identified in bovine, human, and rat genomes. The alpha-, beta-, and gamma-type protein kinase sequences are highly homologous, include a kinase domain, and potential calcium-binding sites, and they contain interspersed variable regions. The corresponding genes are located on distinct human chromosomes; the possibility of even greater genetic complexity of this gene family is suggested by Northern and Southern hybridization analyses.

The complete primary structure of protein kinase C--the major phorbol ester receptor

Protein kinase C, the major phorbol ester receptor, was purified from bovine brain and through the use of oligonucleotide probes based on partial amino acid sequence, complementary DNA clones were derived from bovine brain complementary DNA libraries. Thus, the complete amino acid sequence of bovine protein kinase C was determined, revealing a domain structure. At the amino terminal is a cysteine-rich domain with an internal duplication; a putative calcium-binding domain follows, and there is at the carboxyl terminal a domain that shows substantial homology, but not identity, to sequences of other protein kinase.

Prospective study on the relationship between intensive bactericidal therapy and leprosy reactions

A systematic study was performed on the reactions occurring during several short-course therapy regimens for the treatment of paucibacillary and multibacillary patients. Most type 1 upgrading reactions in paucibacillary (PB) leprosy were mild to moderate and of short duration, while the time of onset was extremely variable. Their incidence was higher in the regimen rifampin (RMP) 900 mg once weekly for ten weeks than when a single dose of RMP 40 mg/kg body weight was given or 1500 mg in one dose followed by one year of dapsone (DDS) 100 mg daily. In multibacillary (MB) leprosy, three regimens were compared: MB-WHO regimen; regimen C, consisting of daily RMP 600 mg, ethionamide (ETH) 500 mg, and DDS or clofazimine (CLO) 100 mg for six months, followed by six months of daily DDS or CLO; and regimen D, identical to regimen C but comprising daily DDS or CLO plus ETH 500 mg during the second semester. Type 1 upgrading reactions occurred more frequently in MB patients and were more severe than in PB patients. They occurred more frequently and were more severe in regimens C and D than in the MB-WHO regimen. CLO 100 mg daily prevented type 1 reactions in MB patients and rendered them less severe. ENL was also more frequent in regimens C and D and was not prevented by CLO in the dosage used. Although there is some correlation between type 1 reactions and the total amount of RMP administered, other aspects of RMP administration.(ABSTRACT TRUNCATED AT 250 WORDS)

Structural alteration of viral homologue of receptor proto-oncogene fms at carboxyl terminus

A role for proto-oncogenes in the regulation and modulation of cell proliferation has been suggested by the findings that the B-chain of platelet-derived growth factor (PDGF) is encoded by the proto-oncogene sis and that the erb-B oncogene product is a truncated form of the epidermal growth factor (EGF) receptor. Furthermore, the product of the proto-oncogene fms (c-fms) may be related or identical to the receptor for macrophage colony-stimulating factor (CSF-1). v-fms is the transforming gene of the McDonough strain of feline sarcoma virus (SM-FeSV) and belongs to the family of src-related oncogenes which have tyrosine-specific kinase activity. Furthermore, nucleotide sequence analysis of the v-fms gene product revealed topological properties of a cell-surface receptor protein. To elucidate the features involved in the conversion of a normal cell-surface receptor gene into an oncogenic one, we have now determined the complete nucleotide sequence of a human c-fms complementary DNA. The 972-amino-acid c-fms protein has an extracellular domain, a membrane-spanning region, and a cytoplasmic tyrosine protein kinase domain. Comparison of the feline v-fms and human c-fms sequences reveals that the proteins share extensive homology but have different carboxyl termini.

Tyrosine kinase receptor with extensive homology to EGF receptor shares chromosomal location with neu oncogene

A novel potential cell surface receptor of the tyrosine kinase gene family has been identified and characterized by molecular cloning. Its primary sequence is very similar to that of the human epidermal growth factor receptor and the v-erbB oncogene product; the chromosomal location of the gene for this protein is coincident with the neu oncogene, which suggests that the two genes may be identical.

Topology of signal recognition particle receptor in endoplasmic reticulum membrane

The signal recognition particle (SRP) receptor is an integral membrane protein of the endoplasmic reticulum which, in conjunction with SRP, ensures the correct targeting of nascent secretory proteins to this membrane system. From the complementary DNA sequence we have deduced the complete primary structure of the SRP receptor and established that its amino-terminal region is anchored in the membrane. The anchor fragment and the cytoplasmic fragment contribute jointly to a functionally important region which is highly charged and may function in nucleic acid binding.

The neu gene: an erbB-homologous gene distinct from and unlinked to the gene encoding the EGF receptor

The neu oncogene, identified in ethylnitrosourea-induced rat neuroglioblastomas, had strong homology with the erbB gene that encodes the epidermal growth factor receptor. This homology was limited to the region of erbB encoding the tyrosine kinase domain. It was concluded that the neu gene is a distinct novel gene, as it is not coamplified with sequences encoding the EGF receptor in the genome of the A431 tumor line and it maps to human chromosome 17.

Structural gene for beta-nerve growth factor not defective in familial dysautonomia

The developmental loss of neurons in sympathetic, sensory, and some parasympathetic ganglia in familial dysautonomia suggests an inherited defect in the action of beta-nerve growth factor (beta-NGF). The role of this growth factor in dysautonomia has been difficult to resolve as there is no known source of authentic human beta-NGF. The availability of a cloned DNA probe for the human beta-NGF gene has allowed identification of some copies of the gene (alleles) in six affected families. Alleles differ in the length of restriction endonuclease fragments that hybridize to DNA probes for the gene. In two families, affected children did not inherit the same two alleles at the beta-NGF locus. Since this disease is transmitted in an autosomal recessive manner, affected children must share the same alleles at the locus causing the disease. This analysis excludes the beta-NGF gene region as the cause of this neurologic disease but does not eliminate other genes involved in beta-NGF action, such as those coding for processing enzymes, receptors, or other subunits of the NGF complex.

Human epidermal growth factor receptor cDNA sequence and aberrant expression of the amplified gene in A431 epidermoid carcinoma cells

The complete 1,210-amino acid sequence of the human epidermal growth factor (EGF) receptor precursor, deduced from cDNA clones derived from placental and A431 carcinoma cells, reveals close similarity between the entire predicted v-erb-B mRNA oncogene product and the receptor transmembrane and cytoplasmic domains. A single transmembrane region of 23 amino acids separates the extracellular EGF binding and cytoplasmic domains. The receptor gene is amplified and apparently rearranged in A431 cells, generating a truncated 2.8-kilobase mRNA which encodes only the extracellular EGF binding domain.

The human gene for the beta subunit of nerve growth factor is located on the proximal short arm of chromosome 1

Fragments of the recently cloned human gene for the beta subunit of nerve growth factor (beta-NGF) were used as hybridization probes in analyzing two sets of rodent-human somatic cell hybrids for the presence of human beta-NGF sequences. Results from the first set of hybrids assigned the human beta-NGF gene to chromosome 1 and ruled out the presence of sequences of comparable homology on any other chromosome. With the second set of hybrids, which contained seven different, but overlapping, regions of chromosome 1, the NGF locus was mapped to band 1p22.