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Fibroblast activation protein (FAP) generally shows low or undetectable expression in most normal tissues but is highly expressed in fibroblasts in almost all carcinomas. FAP is one of the potential molecules to detect activated fibroblasts and has multiple roles in tumour progression. We generated transgenic mice that specifically expressed tdTomato along with FAP promoter activity. Coculturing a mouse gastric cancer cell line and FAP-tdTomato transgenic mouse-derived fibroblasts showed that tdTomato expression was elevated in the cocultured fibroblasts. Moreover, stomach wall transplanted tumours in mice also showed FAP-tdTomato expression in fibroblasts of the stomach and each metastatic legion. These results indicated that FAP-tdTomato expression in fibroblasts was elevated by stimulation through the interaction with cancer cells. Functionally, collagen production was increased in FAP/tdTomato-positive fibroblasts cocultured with mouse cancer cells. These FAP-tdTomato transgenic mice have the potential to be used to investigate real-time FAP dynamics and the importance of FAP expression in tumour development.

Remodeling the tumor microenvironment (TME) to benefit cancer cells is crucial for tumor progression. Although diffuse-type gastric cancer (DGC) preferentially interacts with the TME, the precise mechanism of the complicated network remains unknown. This study aimed to investigate the mutual activation mechanism underlying DGC progression.Mass cytometry analysis of co-cultured macrophages, noncancerous fibroblasts (NFs), and DGC cells was performed. RNA sequencing was applied to examine gene expression in fibroblasts. DGC cells were treated with cytokines to examine their effect on characteristic changes. The TCGA and Kumamoto University cohorts were used to evaluate the clinical relevance of the in vitro findings.Cohort analysis revealed that DGC patients had a poor prognosis. The fibroblasts and macrophages interacted with DGC cells to form a cell cluster in the invasive front of DGC tissue. The original 3D triple co-culture system determined the promotional effects of nonmalignant cells on DGC invasive growth. We notably identified a mixed-polarized macrophage cell type with M1/M2 cell surface markers in a triple co-culture system. IL-1β from mixed-polarized macrophages induced the conversion of NFs to cancer-associated fibroblast-like (CAF-like) cells, promoting the malignant phenotype of DGC cells by inducing the secretion of IL-6, IL-24, and leukemia inhibitory factor (LIF). Moreover, IL-6 and colony stimulating factor 2 (GM-CSF) cooperated to maintain the stable state of mixed-polarized macrophages. Finally, we found that mixed-polarized macrophages were frequently detected in DGC tissues.These findings demonstrated that mixed-polarized macrophages exist as a novel subtype through the reciprocal interaction between DGC cells and nonmalignant cells.

The arachidonic acid cascade is a major inflammatory pathway that produces prostaglandin E

Polymer coatings are widely used in industrial applications. The mechanical properties of these polymer coatings are known to vary with temperature and deformation rate. The characterization of the dynamic mechanical properties of these coatings at high temperatures via traditional uniaxial testing is challenging often due to their brittleness and small size. In this paper, the mechanical properties of polymer coatings are reported with emphasis on their dynamic mechanical properties at temperatures up to 280 °C characterized by a dynamic nanoindentation technique with a sharp indenter tip. Nanoindentation was used to characterize the mechanical response with emphasis on dynamic mechanical properties of polymer coatings enclosed in a high-temperature stage. To verify the method, the viscoelastic properties of a reference polyethylene terephthalate polyester film were also characterized by uniaxial cyclic tensile testing which exhibited an excellent agreement with the proposed technique. The proposed nanoindentation method can be applied to other polymer coatings and thin films that are used in applications at high temperatures.

VG2025 is a genetically modified HSV-1 oncolytic virus (OV) wherein the transcription and translation of critical viral genes are regulated to enhance virus safety and promote tumor specific virus replication without attenuating the virus. The TTDR design is based on transcriptional control of the essential HSV-1 immediate-early protein ICP27 using a tumor specific CEA promoter, coupled with translational control of the key neurovirulence factor ICP34.5 accomplished by introducing multiple tandem copies of miRNA binding sites for miR-124 and miR-143 which are downregulated in tumors but abundantly expressed in normal brain tissues. The anti-tumor and immune stimulatory properties of VG2025 are also enhanced by expressing a pair of cytokines (IL-12 and IL-15/IL-15Rα complex) that are linked by 2A cleavage peptides and controlled by the tumor specific promoter CXCR4. The dual regulation strategy was verified in vitro and shown to be highly selective. Growth of VG2025 virus correlated with CEA expression in a panel of cell lines including normal cells and a selection of tumor cells with varying CEA levels. miRNA-mediated regulation of ICP34.5 expression was validated by transfecting HEK293t cells with miR-124 and miR-143 precursors, followed by infection with VG2025. RT-qPCR testing revealed a significant decrease in the levels of viral ICP34.5 mRNA when the miRNA was present. VG2025 virus replication was evaluated in a variety of human tumor cell lines, and two cell lines representing NSCLC and pancreatic cancer (A549 and BxPC3, respectively) were selected for testing in a humanized mouse model, where VG2025 displayed strong in vivo anti-tumor efficacy. The immune stimulatory characteristics of VG2025, and the bioactivity of expressed cytokines, were demonstrated in a syngeneic mouse colorectal tumor model (CT26) and lymphoma model (A20) using VG2026, which is an identical mouse specific variant of VG2025 that expresses murine IL-12 in place of human IL-12. In addition to a significant reduction in the growth of injected tumors, we observed a clear abscopal effect on contralateral tumors, indicating a robust anti-tumor immune response with an immune memory effect. Due to the tendency of HSV-1 to establish latency which may lead to neurotoxicity and potential safety concerns, we performed a safety pharmacology study by subcutaneously inoculating immunocompetent DBA mice with VG2025. Absence of neurotoxicity was further verified by more aggressive routes of administration, including via the nose and by corneal scarification. The risk of VG2025 reactivation from a latent state was evaluated in a two-step study: latent infection in the CNS was first established and confirmed, then the trigeminal ganglia were removed and co-cultured with Vero cells to detect reactivation-related cytopathic effects. All studies showed that VG2025 was safe with no reactivation events detected. Citation Format: Yanal Murad, Guoyu Liu, I-Fang Lee, Zahid Delwar, Dmitry Chouljenko, Will Liu, Jun Ding, Luke Bu, Ronghua Zhao, William Jia. VG2025: Transcriptional and translational dually regulated (TTDR) oncolytic virus for cancer immunotherapy [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 5205.

Summary: In the tumor microenvironment, senescent non-malignant cells, including cancer-associated fibroblasts (CAFs), exhibit a secretory profile under stress conditions; this senescence-associated secretory phenotype (SASP) leads to cancer progression and chemoresistance. However, the role of senescent CAFs in metastatic lesions and the molecular mechanism of inflammation-related SASP induction are not well understood. We show that pro-inflammatory cytokine-driven EZH2 downregulation maintains the SASP by demethylating H3K27me3 marks in CAFs and enhances peritoneal tumor formation of gastric cancer (GC) through JAK/STAT3 signaling in a mouse model. A JAK/STAT3 inhibitor blocks the increase in GC cell viability induced by senescent CAFs and peritoneal tumor formation. Single-cell mass cytometry revealed that fibroblasts exist in the ascites of GC patients with peritoneal dissemination, and the fibroblast population shows p16 expression and SASP factors at high levels. These findings provide insights into the inflammation-related SASP maintenance by histone modification and the role of senescent CAFs in GC peritoneal dissemination.

Smoking is the number one risk factor for cancer mortality but only 15–20% of heavy smokers develop lung cancer. It would, therefore, be of great benefit to identify those at high risk early on so that preventative measures can be initiated. To investigate this, we evaluated the effects of smoking on inflammatory markers, innate and adaptive immune responses to bacterial and viral challenges and blood cell composition. We found that plasma samples from 30 heavy smokers (16 men and 14 women) had significantly higher CRP, fibrinogen, IL-6 and CEA levels than 36 non-smoking controls. Whole blood samples from smokers, incubated for 7 h at 37 °C in the absence of any exogenous stimuli, secreted significantly higher levels of IL-8 and a number of other cytokines/chemokines than non-smokers. When challenged for 7 h with E. coli, whole blood samples from smokers secreted significantly lower levels of many inflammatory cytokines/chemokines. However, when stimulated with HSV-1, significantly higher levels of both PGE2 and many cytokines/chemokines were secreted from smokers’ blood samples than from controls. In terms of blood cell composition, red blood cells, hematocrits, hemoglobin levels, MCV, MCH, MCHC, Pct and RDW levels were all elevated in smokers, in keeping with their compromised lung capacity. As well, total leukocytes were significantly higher, driven by increases in granulocytes and monocytes. In addition, smokers had lower NK cells and higher Tregs than controls, suggesting that smoking may reduce the ability to kill nascent tumor cells. Importantly, there was substantial person-to person variation amongst smokers with some showing markedly different values from controls and others showing normal levels of many parameters measured, indicating the former may be at significantly higher risk of developing lung cancer.

The effectiveness of current chemotherapies for cancer is gradually progressing; however achieving a complete cure through chemotherapy is still difficult and has been the main goal in treatment of advanced cancer. Drug resistance is an issue in cancer therapy, therefore increasing numbers of investigations into drug resistance have focused on the characteristics of the cancer cells themselves. The interaction between the tumor microenvironment (TME) and cancer cells is also intimately involved in the development of drug resistance. Cancer‐associated fibroblasts (CAFs) are a predominant component of the TME and affect tumor progression by secreting soluble factors. This review summarizes the most up‐to‐date knowledge of CAFs and drug resistance in cancer, with a focus on factors secreted from CAFs including proteins, cytokines, extracellular vesicles, and metabolites. A perspective on the potential role of anti‐CAF therapies in overcoming CAF‐induced drug resistance is also discussed., Drug resistance is a main issue for anticancer therapies. Cancer‐associated fibroblasts (CAFS) have a huge effect in promoting drug resistance. This review summarizes the current perspectives on the role of CAFs in chemoresistance.

Gastric cancer (GC) is a leading cause of cancer-related death worldwide. Cancer stem cells (CSCs) are known to be involved in chemotherapy resistance and the development of metastases. Although CSCs harbor self-renewal and tumorigenic abilities, the immune microenvironment surrounding CSCs provides various factors and supports the maintenance of CSC properties. The current review summarizes the accumulating findings regarding the relationship between the immune microenvironment and gastric CSCs (GCSCs), which will support the possibility of developing novel therapeutic strategies for targeting GCSCs.

Obesity has reached epidemic proportions and is often accompanied by elevated levels of pro-inflammatory cytokines that promote many chronic diseases, including cancer. However, not all obese people develop these diseases and it would be very helpful to identify those at high risk early on so that preventative measures can be instituted. We performed an extensive evaluation of the effects of obesity on inflammatory markers, on innate and adaptive immune responses, and on blood cell composition to identify markers that might be useful in distinguishing those at elevated risk of cancer. Plasma samples from 42 volunteers with a BMI>35 had significantly higher CRP, PGE2, IL-1RA, IL-6 and IL-17 levels than 34 volunteers with normal BMIs. Of the cytokines and chemokines tested, only IL-17 was significantly higher in men with a BMI>35 than women with a BMI>35. As well, only IL-17 was significantly higher in those with a BMI>35 that had type 2 diabetes versus those without type 2 diabetes. Whole blood samples from participants with a BMI>35, when challenged with E. coli, produced significantly higher levels of IL-1RA while HSV-1 challenge resulted in significantly elevated IL-1RA and VEGF, and a non-significant increase in G-CSF and IL-8 levels. T cell activation of PBMCs, via anti-CD3 plus anti-CD28, resulted in significantly higher IFNγ production from volunteers with a BMI>35. In terms of blood cells, red blood cell distribution width (RDW), monocytes, granulocytes, CD4+T cells and Tregs were all significantly higher while, natural killer (NK) and CD8+ T cells were all significantly lower in the BMI>35 cohort, suggesting that obesity may reduce the ability to kill nascent tumor cells. Importantly, however, there was considerable person-to-person variation amongst participants with a BMI>35, with some volunteers showing markedly different values from controls and others showing normal levels of many parameters measured. These person-to-person variations may prove useful in identifying those at high risk of developing cancer.

Chronic inflammation has a crucial role in cancer development and the progression of various tumors, including pancreatic ductal adenocarcinoma (PDAC). The arachidonate cascade is a major inflammatory pathway that produces several metabolites, such as prostaglandin E2. The enzyme 15‐hydroxyprostaglandin dehydrogenase (15‐PGDH) degrades prostaglandin and is frequently decreased in several types of cancer; however, the molecular mechanisms of 15‐PGDH suppression are unclear. The current study was carried out to elucidate the molecular mechanisms and clinical significance of 15‐PGDH suppression in PDAC. Here, we showed that interleukin‐1β (IL‐1β), a pro‐inflammatory cytokine, downregulates 15‐PGDH expression in PDAC cells, and that IL‐1β expression was inversely correlated with 15‐PGDH levels in frozen PDAC tissues. We also found that activated macrophages produced IL‐1β and reduced 15‐PGDH expression in PDAC cells. Furthermore, the number of CD163‐positive tumor‐associated macrophages was shown to be inversely correlated with 15‐PGDH levels in PDAC cells by immunohistochemical staining of 107 PDAC samples. Finally, we found that low 15‐PGDH expression was significantly associated with advanced tumors, presence of lymph node metastasis and nerve invasion, and poor prognosis in PDAC patients. Our results indicate that IL‐1β derived from TAMs suppresses 15‐PGDH expression in PDAC cells, resulting in poor prognosis of PDAC patients.

Acute myeloid leukemia (AML) is the most common human leukemia and is a major area of unmet medical need among hematologic malignancies. Progress has been made in identifying therapeutic targets and several approved therapies, but resistance to frontline chemotherapy remains a major cause of treatment failure, highlighting the need for new therapies. Oncolytic viruses (OV) are a promising new class of therapeutics that rely on tumor specific oncolysis and the generation of a potent adaptive anti-tumor immune response for efficacy. To investigate if our newly developed oncolytic herpes simplex viruses (oHSVs), designed to potentiate anti-leukemia immunity, effectively target primitive AML cells, we evaluated oHSV-VG161, which is engineered to express IL-12, IL-15 and the IL-15 receptor alpha subunit, along with a peptide fusion protein capable of disrupting PD-1/PD-L1 interaction. After screening several AML cell lines that expressed relatively high levels of a HSV entry receptor (HVEM), we demonstrated that VG161-infected OCIAML3 and MOLM13 cells significantly enhanced cell killing (IC 50: 0.4 & 1.8 multiplicity of infection (MOI) as compared to MV4-11 and U973 cells (IC 50: 3.0 & 9.5 MOI). These effects were 2-3 folds lower in control VG160-infected cells. We also observed that VG161-infected AML cells induced apoptosis in a dose-dependent manner (~50%) after 48 hours and cleaved PARP, Caspase-3 and Caspase-8 were increased in these cells, and to a lesser extent in control VG160-infected cells. Both VG160 and VG161 viruses replicated efficiently in OCIAML3 and MOLM13 cells in a timely, dose-dependent manner, evidenced by qPCR detection of HSV-1 ICP27 DNA copy numbers (>500-fold increase) over 48 hours of treatment. This result was supported by detection of protein expression of HSV-1 glycoprotein D in VG160 and VG161-infected cells (up to 40% of protein detected) by FACS analysis. Interestingly, IL-12 but not IL-15 protein expression was found in intracellular-stained VG161-infected OCIAML3 and MOLM13 cells in a dose-dependent manner (up to 13% of protein detected, P Disclosures No relevant conflicts of interest to declare.

A two-step synthesis of polyimide reaction from dianhydride and diamine was followed by both infrared (IR) and Raman spectroscopy in situ in this case study. In the first step, the two reactants form poly(amide acid), which resulted in substantial spectral changes easily detected by both spectroscopic techniques. The reaction was found to occur rapidly and reached completion within tens of minutes at room temperature. In the second step, trimethylamine (catalyst) and acetic anhydride (dehydration agent) were added to form the five-member imide ring. Interestingly, different spectral changes were observed using IR and Raman spectroscopic methods due to their different responses toward the various functional groups involved. Conclusive evidence was also obtained based on the Raman results to demonstrate a long-lived intermediate species, which was harder to observe in the IR results. This work provides a good case study of the combined use of different vibrational spectroscopy techniques to extract maximum information from a reaction system.

Herein we demonstrate that ultraviolet light-inactivated Herpes Simplex Virus-1 (UV-HSV-1) stimulates peripheral blood mononuclear cells (PBMCs) to lyse both androgen-sensitive and androgen-independent prostate cancer (PrCA) cell lines, but not the benign prostatic hyperplastic epithelial cell line, BPH-1, and is 1000-10,000-fold more potent at stimulating this killing than ultraviolet light-inactivated Vesicular Stomatitis Virus, adenovirus, reovirus or cytomegalovirus. Among PBMCs, natural killer (NK) cells appear to be a major cell type involved in this killing and UV-HSV-1 appears to directly and potently stimulate NK cell expression of CD69, degranulation, cytokine production, and migration to IL-8 in PC3 conditioned medium. We also found that UV-HSV-1 stimulates glycolysis in PBMCs and NK cells, and that 2-deoxyglucose and the protein kinase C inhibitor, Go6976, and the NFκB inhibitor, Bay 11-7082, all abrogate UV-HSV-1 activated killing of PC3 cells by PBMCs and NK cells. Using neutralizing anti-Toll-like receptor 2 (TLR2) we found that UV-HSV-1, like HSV-1, activates NK cells via TLR2. Taken together, these results are consistent with Toll-like receptor 2 ligands on UV-HSV-1 stimulating TLR2 on NK cells to activate protein kinase C, leading to enhanced glycolysis and NFκB activation, both of which play a critical role in this anti-PrCA innate immune response. Importantly, UV-HSV-1 synergizes with IL-15 to increase the cytolytic activity of PBMCs against PC3 cells and there was considerable donor-to-donor variation in killing ability. These results support the preclinical development of UV-HSV-1 as an adjuvant, in combination with IL-15, for cell infusions of healthy, preselected NK cells to treat PrCA.

Oncolytic viruses (OVs) are the wild-type or genomic modified viruses, which can specifically replicate in cancer cells but not in normal cells. They cause cancer cell lysis and more importantly, their replication in tumor cells induces an antitumor immune response from the host. As synergistic stimulation of antitumor immune response requires multiple immune-regulatory factors, OVs armed with multiple immune-modulating factors are of high potential in cancer immunotherapy. We have constructed a novel herpes simplex virus type-1 virus (HSV-1), VG161, that is armed with IL12, IL15, and a unique PDL-1 peptide blocker. The aim of this study is to investigate the anticancer efficacy of VG161 in gastrointestinal (GI) cancers including gastric, hepatic, and colorectal cancers. The immune-stimulating activities in tumor-bearing immune competent mice were also demonstrated. VG161 was given to the tumor-bearing animals by intratumor injection (5 × 106-5 × 107 PFU/animal, once a day for 3-5 days). Antitumor activity of VG161 was tested in both immune-deficient mice as well as in immune-competent mice. Oncolytic activity of VG161 was demonstrated in human gastric (SGC-7901), hepatic (patient-derived xenograft, PDX), and colorectal (LS174T) cancer-bearing nude mice as the human tumors are susceptible to HSV infection and the immune system is compromised in those models. To determine the antitumor immune response activated by VG161, colorectal cancer (CT26) syngeneic model was used in immune competent animals and T cell subpopulation analysis, ELISPOT, and tumor rechallenge assay was applied to measure specific antitumor immunity. VG161 caused complete tumor eradication in PDX and CT26 tumor models and significantly inhibited tumor growth in SGC-7901 and LS174T models. All animals treated with VG161 survived for many months till sacrificed. In the CT26 model, no tumor could be found after rechallenging with the same tumor cells. The number of CD8+ tumor infiltrated T cells was significantly increased, and systemic specific anticancer immunity was confirmed by ELISPOT assay on T cells isolated from spleen. VG161 is a novel oncolytic virus that is both strong in oncolysis and stimulating antitumor immunity for GI cancers. Intratumorally expressing multiple immune-regulatory factors by an oncolytic virus may significantly change the GI tumor immune microenvironment and stimulate anticancer immunity, to further enhance the efficacy of the oncolytic virus. Citation Format: Ronghua Zhao, Jun Ding, Tianchi Liu, Shuyun Liu, Dmitry Chouljenko, Yanal Murad, Erica Lee, Guoyu Liu, Luke Bu, William Jia. Anticancer efficacy of a novel immune-stimulating oncolytic virus: VG161 in gastrointestinal cancers [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2018 Nov 27-30; Miami Beach, FL. Philadelphia (PA): AACR; Cancer Immunol Res 2020;8(4 Suppl):Abstract nr B85.

The accumulation of prostaglandin E2 (PGE2) during chronic inflammation has been implicated in the progression of several cancers. Cyclooxygenase is the key synthesizing enzyme of PGE2, although the degradation enzyme 15-hydroxyprostaglandin dehydrogenase (15-PGDH) has received considerable attention recently. We investigated the molecular mechanisms of pancreatic ductal adenocarcinoma (PDAC) progression via 15-PGDH downregulation. Here, we found that 15-PGDH expression was inversely correlated with ALDH1, an important cancer stem cell-associated marker indicative of poor prognosis in humans. Moreover, we demonstrated that pharmacological inhibition of 15-PGDH enhanced CYP26A1 expression, leading to depletion of all-trans retinoic acid (ATRA) and expansion of the ALDH1-positive subset in both human PDAC cells and tumor cells of KrasLSL-G12D/+; Ptf1aCre/+ (KC) mice. Furthermore, genetic deletion of 15-Pgdh in KC mice showed PGE2 accumulation and ATRA depletion in the pancreas, resulting in PDAC with high levels of Aldh1 and Ki-67. Finally, ATRA replacement suppressed 15-PGDH inhibition-induced tumor progression in KC mice, and ATRA treatment attenuated Aldh1 activity in tumor cells isolated from the pancreas of 15-Pgdh-/- KC mice. These findings provide evidence that 15-PGDH inhibition enhances KRAS-driven tumor progression via ATRA depletion in the pancreas. Therefore, ATRA replacement could be a potential strategy for PDAC treatment.

To identify reliable biomarkers of age-related changes in chronic inflammation and responsiveness to bacterial and viral challenges, we evaluated endogenous and ex vivo stimulated levels of 18 inflammatory markers, using whole blood collected in EDTA and sodium heparin tubes from 41 healthy volunteers, i.e., 11 men + 10 women aged 20-35 and 10 men + 10 women aged 50-77. These studies revealed significant differences in the levels of inflammatory markers when blood was collected in EDTA versus sodium heparin and age related differences in these biomarkers were confirmed with blood collected in EDTA from 120 healthy volunteers in 3 age categories, ie, 20 men + 20 women, aged 20-35, 36-49 and 50-77. Studies with unstimulated blood samples, to measure levels of chronic inflammation, revealed a significant increase with age in IL-12p70, CRP and PGE2, consistent with the concept of "inflammaging", and a decrease in G-CSF in both men and women. Interestingly, in response to E. coli stimulation, PGE2 levels were markedly reduced in the 50-77 year old cohort while they were increased following Herpes Simplex virus-1 (HSV-1) stimulation, along with IL-8. In addition, unlike E. coli, HSV-1 potently stimulated IFNα production, but levels were dramatically reduced in the older cohort, consistent with a reduced ability to generate an anti-viral response. We also found platelets and CD8+ T cells were reduced with age while CD4+ T cells were significantly increased, resulting in a substantially higher CD4/CD8 ratio in the older cohort. Surprisingly, however, we found that the older cohort exhibited more T cell proliferation and IFNγ production in response to anti-CD3+anti-CD28 stimulation. Importantly, there was considerable person-to-person variation in these inflammatory markers in all age groups, making possible comparisons between a person's "inflammage" and chronological age. These assays should help to identify individuals at high risk of autoimmune disorders and cancer.

Oncolytic viruses (OVs) are among the most powerful approaches in cancer immunotherapy. OVs not only cause cancer cell lysis but more importantly, their infection in tumors induces anti-tumor immune response from the host, resulting in lasting anti-tumor immunity. It has been recognized that anti-tumor immune response requires multiple immune regulatory factors that act synergistically and tumor microenvironment is critical for tumor to grow. Herpes simplex virus type-1 (HSV-1) has been approved by FDA as an oncolytic viral drug to treat melanoma. One advantage of HSV-1 is its large genomic capacity for carrying multiple exogenous genes.A HSV-1 oncolytic viral vector (VG161) was constructed to simultaneously express IL12, IL15 with its receptor alpha unit and a PDL-1 blocking peptide. Antitumor activity of VG161 was tested in both immune competent mice (CT26 and A20 tumor models) and nude mice for human tumor models (LNCaP and U87). Since CT26 and A20 are poorly permissive for HSV-1 replication, the mouse tumor models were able to demonstrate the antitumor immune response induced by VG161 while oncolytic activity of VG161 was demonstrated in LNCaP and U87 models since the immune system is compromised in those models.VG161 completely inhibited tumors in all the models tested and the animals survived tumor-free for many months till sacrificed. VG161 induced tumor oncolysis in both LNCaP and U87 tumors. In the CT26 model, animals were protected from the second challenging with CT26 cells following previous virally induced tumor regression. Furthermore, in a A20 double tumor model, intratumoral injection into the tumor on one side caused tumor regression on both sides. Transcriptome analysis showed significant change in tumor microenvironment. Finally, tumor specific memory T-cells were evident in the treated animals. The anti-tumor immune response by VG161 was significantly stronger than similar viruses that did not express any immune stimulating gene or only express GM-CSF. These results showed that intratumorally expressed multiple immune regulatory factors by an oncolytic virus may significantly change the tumor immune microenvironment to enhance efficacy of the oncolytic virus. Citation Format: Ronghua Zhao, Jun Ding, Dmitry Choujenko, Yanal Murad, Erica Lee, Guoyu Liu, Luke Bu, William Jia. Synergistic activation of antitumor immunity by an oncolytic virus VG161 armed with multiple immune-stimulating genes [abstract]. In: Proceedings of the Fourth CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; Sept 30-Oct 3, 2018; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2019;7(2 Suppl):Abstract nr B059.

Chronic inflammation has a crucial role in cancer development and the progression of various tumors, including pancreatic ductal adenocarcinoma (PDAC). The arachidonate cascade is a major inflammatory pathway that produces several metabolites, such as prostaglandin E2 (PGE2). 15-hydroxyprostaglandin dehydrogenase (15-PGDH) participates in the degradation of PGE2 and has attracted attention in recent years. Although inhibition of 15-PGDH is reported to lead to PGE2 accumulation and expand tissue stem cell fraction, the role for pancreatic tumor progression is still unknown. The aim of this study is to elucidate the regulatory mechanism and functional role of 15-PGDH for cancer stem-like cell expansion during tumor progression in pancreas. We found that 15-PGDH expression is frequently down-regulated in PDAC cells and significantly correlated with the number of infiltrating macrophages in human PDAC tissues. Moreover, direct co-culture assay revealed that macrophage derived interleukin-1 beta down-regulates 15-PGDH expression in PDAC cells. Furthermore, pharmacological blockade of 15-PGDH led to PGE2 accumulation, and promoted growth and sphere formation through the expansion of ALDH1-positive cells. We also elucidated the molecular mechanism that PGE2 accumulation by 15-PGDH inhibition increases CYP26A1 expression and subsequently depletes all-trans retinoic acid, and results in ALDH1 up-regulation. Finally, genetic ablation of 15-Pgdh promoted tumorigenesis in KrasLSL-G12D; Ptf1aCre/+ mice through the expansion of ALDH1-positive cells. Our findings highlight the role and significance of PGE2 degradation pathway for PDAC tumor progression. Citation Format: Takatsugu Ishimoto, Kota Arima, Luke Bu, Tomoyuki Uchihara, Keisuke Miyake, Tsugio Eto, Rumi Itoyama, Hideo Baba. Expansion of pancreatic cancer stem-like cells through PGE2 accumulation in inflammatory environment [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 1987.

Oncolytic HSV-1 (oHSV-1) are among the most promising therapies for cancer. Besides the oncolytic activity delivered by the virus against tumor cells, this treatment can also induce a potent immune response against tumor antigens (whether classic TAA, or neoantigens specific to the tumor being targeted). We have constructed an oncolytic HSV-1 virus (VG161) to deliver 2 immunomodulator cytokines, IL12 and IL15, to the tumor micro-environment. These two cytokines can work synergistically to trigger an efficient anti-tumor immune response. A PD-L1 mimic peptide capable of blocking PD-1/PD-L1 interaction is also delivered as a Fc fusion peptide (TF-Fc) to help in maintaining an effective immune response against the tumor. For the construction of the recombinant virus, the exogenous components were cloned under CMV promoter control. The ICP34.5 gene was deleted as a safety measure for the recombinant virus. The expression of Il12, IL15 and TF-Fc were confirmed, in vitro and in vivo, by qRT-PCR, ELISA and Western blot. Upon intra-tumoral injection of VG161, expressed IL12, IL15 and TF-Fc were detected only in the injected tumor mass, but not in the animals' blood or other organs. The bio-distribution of the virus was tested by qPCR after injecting VG161 intratumorally, and most of the injected virus were concentrated in the tumor mass. Minimal amounts of the virus were detected in the liver and spleen for short periods after virus injection. We have demonstrated the superior activity of the VG161 virus, compared to the back-bone virus (with no payloads) using immune-competent mouse models (CT26) and nude mice implanted with human tumor cells lines (LNCaP and U87). VG161 induced tumor oncolysis resulting in complete tumor regression in nude mice. In the CT26 model, the tumor regressed to undetectable limits upon intra-tumoral injection with VG161. When the treated mice were challenged with the same tumor, the tumor cells did not grow. The added efficacy in CT26 tumor model can be attributed to the immune response generated by the modified virus, as demonstrated by a higher number of tumor-infiltrating CD8 T cells. The specific activity of T cells against the tumor cells was also demonstrated by ELISpot assay. Finally, memory T-cells were evident in the treated animals demonstrated by multiple assays. Conclusions This work has demonstrated the safety and efficacy of VG161, a novel oncolytic virus which can induce a strong anti-tumor immunity and oncolytic activity. We have also demonstrated that the Intra-tumoral expression of multiple immune regulatory factors may significantly change the tumor immune microenvironment to enhance the efficacy of the oncolytic virus. Citation Format: Yanal M. Murad, Jun Ding, Dmitry Chouljenko , Erica Lee, Luke Bu, Guoyu Liu, Ronghua Zhao, Zahid Delwar, Will Liu, William Jia. Synergy of immunomodulators delivered by an HSV-1 oncolytic virus can enhance its therapeutic effects in vivo [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 5641.

One of the major causes for cancer cells to resist current chemotherapy is attributed to the over-expression of P-glycoprotein (P-gp), resulting in insufficient drug delivery to the tumor sites. Protopanaxadiol ginsenosides Rg3 and Rh2 are known to induce apoptosis and significantly enhance the tumor inhibitory effects of chemotherapeutics in a synergistic fashion. One of the possible mechanisms is by blocking P-gp activity. The final deglycosylation metabolite of protopanaxadiols (PPDs) IN VIVO is 20S-protopapanaxadiol (aglycone PPD, aPPD), which has also shown anticancer activity and synergy with chemotherapy drugs. In the present study, P-gp over-expressing cancer cells were utilized to test whether aPPD also inhibits P-gp activity. We found that aPPD caused similar cytotoxicity in P388adr cells as their parental non-MDR cells, suggesting that aPPD may not be a substrate of P-gp. On the other hand, the calcein AM efflux assay showed that aPPD was able to inhibit P-gp activity as potently as verapamil on MDR cells. The blockage of P-gp activity was highly reversible as wash-out of aPPD resulted in an immediate recovery of P-gp activity. Unlike verapamil, aPPD did not affect ATPase activity of P-gp suggesting a different mechanism of action. The above results indicate that aPPD, unlike its precursor ginsenosides Rg3 and Rh2, is not a substrate of P-gp. It is also the first time that aPPD has showed a reversible nature of its P-gp inhibition. In addition to its pro-apoptotic nature, aPPD may be a potential new P-gp inhibitor for cancer treatment.

Herein we demonstrate that oncolytic herpes simplex virus-1 (HSV-1) potently activates human peripheral blood mononuclear cells (PBMCs) to lyse leukemic cell lines and primary acute myeloid leukemia samples, but not healthy allogeneic lymphocytes. Intriguingly, we found that UV light–inactivated HSV-1 (UV-HSV-1) is equally effective in promoting PBMC cytolysis of leukemic cells and is 1000- to 10 000-fold more potent at stimulating innate antileukemic responses than UV-inactivated cytomegalovirus, vesicular stomatitis virus, reovirus, or adenovirus. Mechanistically, UV-HSV-1 stimulates PBMC cytolysis of leukemic cells, partly via Toll-like receptor-2/protein kinase C/nuclear factor-κB signaling, and potently stimulates expression of CD69, degranulation, migration, and cytokine production in natural killer (NK) cells, suggesting that surface components of UV-HSV-1 directly activate NK cells. Importantly, UV-HSV-1 synergizes with interleukin-15 (IL-15) and IL-2 in inducing activation and cytolytic activity of NK cells. Additionally, UV-HSV-1 stimulates glycolysis and fatty acid oxidation–dependent oxygen consumption in NK cells, but only glycolysis is required for their enhanced antileukemic activity. Last, we demonstrate that T cell–depleted human PBMCs exposed to UV-HSV-1 provide a survival benefit in a murine xenograft model of human acute myeloid leukemia (AML). Taken together, our results support the preclinical development of UV-HSV-1 as an adjuvant, alone or in combination with IL-15, for allogeneic donor mononuclear cell infusions to treat AML.