Using Oncolytic Virus to Retask CD19-Chimeric Antigen Receptor T Cells for Treatment of Pancreatic Cancer: Toward a Universal Chimeric Antigen Receptor T-Cell Strategy for Solid Tumor

BACKGROUND

Chimeric antigen receptor (CAR) T cells targeting the B-cell antigen CD19 are standard therapy for relapsed or refractory B-cell lymphoma and leukemia. CAR T cell therapy in solid tumors is limited due to an immunosuppressive tumor microenvironment and a lack of tumor-restricted antigens. We recently engineered an oncolytic virus (CF33) with high solid tumor affinity and specificity to deliver a nonsignaling truncated CD19 antigen (CD19t), allowing targeting by CD19-CAR T cells. Here, we tested this combination against pancreatic cancer.

STUDY DESIGN

We engineered CF33 to express a CD19t (CF33-CD19t) target. Flow cytometry and ELISA were performed to quantify CD19t expression, immune activation, and killing by virus and CD19-CAR T cells against various pancreatic tumor cells. Subcutaneous pancreatic human xenograft tumor models were treated with virus, CAR T cells, or virus+CAR T cells.

RESULTS

In vitro, CF33-CD19t infection of tumor cells resulted in >90% CD19t cell-surface expression. Coculturing CD19-CAR T cells with infected cells resulted in interleukin-2 and interferon gamma secretion, upregulation of T-cell activation markers, and synergistic cell killing. Combination therapy of virus+CAR T cells caused significant tumor regression (day 13): control (n = 16, 485 ± 20 mm 3 ), virus alone (n = 20, 254 ± 23 mm 3 , p = 0.0001), CAR T cells alone (n = 18, 466 ± 25 mm 3 , p = NS), and virus+CAR T cells (n = 16, 128 ± 14 mm 3 , p < 0.0001 vs control; p = 0.0003 vs virus).

CONCLUSIONS

Engineered CF33-CD19t effectively infects and expresses CD19t in pancreatic tumors, triggering cell killing and increased immunogenic response by CD19-CAR T cells. Notably, CF33-CD19t can turn cold immunologic tumors hot, enabling solid tumors to be targetable by agents designed against liquid tumor antigens.

Epigenetic age prediction using costal cartilage for the investigation of disaster victims and missing persons

The DNA intelligence tool, DNA methylation-based age prediction, can help identify disaster victims and suspects in criminal investigations. In this study, we developed a costal cartilage-based age prediction tool that uses massive parallel sequencing (MPS) of age-associated DNA methylation markers. Costal cartilage samples were obtained from 85 deceased Koreans, aged between 26 and 89 years. An MPS library was prepared using two rounds of multiplex polymerase chain reaction of nine genes (TMEM51, MIR29B2CHG, EDARADD, FHL2, TRIM59, ELOVL2, KLF14, ASPA, and PDE4C). The DNA methylation status of 45 CpG sites was determined and used to train an age prediction model via stepwise regression analysis. Nine CpGs in MIR29B2CHG, FHL2, TRIM59, ELOVL2, KLF14, and ASPA were selected for regression model construction. A leave-one-out cross-validation analysis revealed the high performance of the age prediction model, with a mean absolute error (MAE) and root mean square error of 4.97 and 6.43 years, respectively. Additionally, our model showed good performance with a MAE of 6.06 years in the analysis of data of 181 costal cartilage samples collected from Europeans. Our model effectively estimates the age of deceased individuals using costal cartilage samples; therefore, it can be a valuable forensic tool for disaster victim and missing person investigation.

Peritoneal-directed chimeric oncolytic virus CF17 prevents malignant ascites and improves survival in gastric cancer peritoneal metastases

Gastric cancer (GC) peritoneal metastasis (PM) is fatal without effective therapy. We investigated CF17, a new replication-competent chimeric poxvirus, against GC cell lines in vitro and PM in an aggressive GCPM mouse model. We performed viral proliferation and cytotoxicity assays on intestinal-type and diffuse-type human GC cell lines following CF17 treatment. At lower MOIs of 0.01, 0.1, there was >80% killing in most cell lines, while in the more aggressive cell lines, killing was seen at higher MOIs of 1.0 and 10.0. We observed reduced peritoneal tumor burden and prolonged survival with intraperitoneal (i.p.) CF17 treatment in nude mice implanted with the resistant GC cell line. At day 91 after treatment, seven of eight mice were alive in the CF17-treated group vs. one of eight mice in the control group. CF17 treatment inhibited ascites formation (0% vs. 62.5% with PBS). Thus, CF17 efficiently infected, replicated in, and killed GC cells in a dose- and time-dependent manner in vitro. In vivo, i.p. CF17 treatment exhibited robust antitumor activity against an aggressive GCPM model to decrease tumor burden, improve survival, and prevent ascites formation. These preclinical results inform the design of future clinical trials of CF17 for peritoneal-directed therapy in GCPM patients.

Anti-Tumor Immunogenicity of the Oncolytic Virus CF33-hNIS-antiPDL1 against Ex Vivo Peritoneal Cells from Gastric Cancer Patients

We studied the immunotherapeutic potential of CF33-hNIS-antiPDL1 oncolytic virus (OV) against gastric cancer with peritoneal metastasis (GCPM). We collected fresh malignant ascites (MA) or peritoneal washings (PW) during routine paracenteses and diagnostic laparoscopies from GC patients (n = 27). Cells were analyzed for cancer cell markers and T cells, or treated with PBS, CF33-GFP, or CF33-hNIS-antiPDL1 (MOI = 3). We analyzed infectivity, replication, cytotoxicity, CD107α upregulation of CD8+ and CD4+ T cells, CD274 (PD-L1) blockade of cancer cells by virus-encoded anti-PD-L1 scFv, and the release of growth factors and cytokines. We observed higher CD45-/large-size cells and lower CD8+ T cell percentages in MA than PW. CD45-/large-size cells were morphologically malignant and expressed CD274 (PD-L1), CD252 (OX40L), and EGFR. CD4+ and CD8+ T cells did not express cell surface exhaustion markers. Virus infection and replication increased cancer cell death at 15 h and 48 h. CF33-hNIS-antiPDL1 treatment produced functional anti-PD-L1 scFv, which blocked surface PD-L1 binding of live cancer cells and increased CD8+CD107α+ and CD4+CD107α+ T cell percentages while decreasing EGF, PDGF, soluble anti-PD-L1, and IL-10. CF33-OVs infect, replicate in, express functional proteins, and kill ex vivo GCPM cells with immune-activating effects. CF33-hNIS-antiPDL1 displays real potential for intraperitoneal GCPM therapy.

An oncolytic poxvirus encoding hNIS, shows anti-tumor efficacy and allows tumor imaging in a liver cancer model

Oncolytic viruses (OVs) are live viruses that can selectively replicate in cancer cells. We have engineered an OV (CF33) to make it cancer-selective through the deletion of its J2R (thymidine kinase) gene. Additionally, this virus has been armed with a reporter gene, human sodium iodide symporter (hNIS), to facilitate non-invasive imaging of tumors using positron emission tomography (PET). In this study we evaluated the oncolytic properties of the virus (CF33-hNIS) in liver cancer model, and its usefulness in tumor imaging. The virus was found to efficiently kill liver cancer cells and the virus-mediated cell death exhibited characteristics of immunogenic death based on the analysis of 3 damage associate molecular patterns (DAMPs): calreticulin, ATP and HMGB1. Furthermore, local or systemic administration of a single dose of the virus showed anti-tumor efficacy against a liver cancer xenograft model in mice and significantly increased survival of treated mice. Lastly, PET scanning was performed following injection of the radioisotope I-124, for imaging of tumors, and a single dose of virus as low as 1E03 pfu, administered intratumorally (I.T.) or intravenously (I.V.), allowed for PET imaging of tumors. In conclusion, CF33-hNIS is safe and effective in controlling human tumor xenografts in nude mice, and it also facilitates non-invasive imaging of tumors.

Development of the oncolytic virus, CF33, and its derivatives for peritoneal-directed treatment of gastric cancer peritoneal metastases

BACKGROUND

Gastric cancer (GC) that metastasizes to the peritoneum is fatal. CF33 and its genetically modified derivatives show cancer selectivity and oncolytic potency against various solid tumors. CF33-hNIS and CF33-hNIS-antiPDL1 have entered phase I trials for intratumoral and intravenous treatments of unresectable solid tumors (NCT05346484) and triple-negative breast cancer (NCT05081492). Here, we investigated the antitumor activity of CF33-oncolytic viruses (OVs) against GC and CF33-hNIS-antiPDL1 in the intraperitoneal (IP) treatment of GC peritoneal metastases (GCPM).

METHODS

We infected six human GC cell lines AGS, MKN-45, MKN-74, KATO III, SNU-1, and SNU-16 with CF33, CF33-GFP, or CF33-hNIS-antiPDL1 at various multiplicities of infection (0.01, 0.1, 1.0, and 10.0), and performed viral proliferation and cytotoxicity assays. We used immunofluorescence imaging and flow cytometric analysis to verify virus-encoded gene expression. We evaluated the antitumor activity of CF33-hNIS-antiPDL1 following IP treatment (3×10⁵ pfu × 3 doses) in an SNU-16 human tumor xenograft model using non-invasive bioluminescence imaging.

RESULTS

CF33-OVs showed dose-dependent infection, replication, and killing of both diffuse and intestinal subtypes of human GC cell lines. Immunofluorescence imaging showed virus-encoded GFP, hNIS, and anti-PD-L1 antibody scFv expression in CF33-OV-infected GC cells. We confirmed GC cell surface PD-L1 blockade by virus-encoded anti-PD-L1 scFv using flow cytometry. In the xenograft model, CF33-hNIS-antiPDL1 (IP; 3×10⁵ pfu × 3 doses) treatment significantly reduced peritoneal tumors (p<0.0001), decreased amount of ascites (62.5% PBS vs 25% CF33-hNIS-antiPDL1) and prolonged animal survival. At day 91, seven out of eight mice were alive in the virus-treated group versus one out of eight in the control group (p<0.01).

CONCLUSIONS

Our results show that CF33-OVs can deliver functional proteins and demonstrate effective antitumor activity in GCPM models when delivered intraperitoneally. These preclinical results will inform the design of future peritoneal-directed therapy in GCPM patients.

Development of a novel chimeric oncolytic viral platform, CF33 and its derivatives, for peritoneal-directed CF33-OV treatment of gastric cancer peritoneal carcinomatosis

428

Background: Peritoneal carcinomatosis (PC) is a deadly end-stage manifestation of gastric cancer (GC). CF33, a chimeric oncolytic virus, and its genetically modified derivatives have shown exclusive cancer selectivity and oncolytic potency against various solid tumors. Intravenous and intratumoral CF33-hNIS and CF33-hNIS-antiPDL1 have entered phase I trials to treat triple-negative breast cancer and unresectable solid tumors. Here, we investigated the antitumor activities of CF33-OVs against GCPC. Methods: We infected six GC cell lines, including both intestinal-type (AGS and MKN-74) and diffuse-type (KATO III, MKN-45, SNU-1, and SNU-16) with CF33, CF33-GFP, or CF33-hNIS-antiPDL1 at various multiplicities (MOI 0.01, 0.1, 1.0 and 10.0) to examine viral proliferation and cytotoxicity by using standard plaque assay and cell proliferation assay. We performed immunofluorescence imaging and flow cytometric analysis to verify virus-encoded gene expression and blockade of PD-L1 binding by virus-encoded anti-PD-L1 scFv. A mouse model of peritoneal dissemination xenograft of SNU-16-ffluc cells was set up to evaluate the antitumor activity of intraperitoneal (IP) CF33-hNIS-antiPDL1 treatment (3x105 pfu x 3 doses). Results: CF33-OVs showed dose-dependent infection, replication, and killing of human GC cell lines. Immunofluorescence imaging showed virus-encoded GFP, hNIS, and anti-PD-L1 scFv expression in CF33-OV-infected GC cells. GC cell surface PD-L1 binding was blocked by virus-encoded anti-PD-L1 scFv. In the xenograft model, IP CF33-hNIS-antiPDL1 treatment significantly reduced peritoneal tumors (p<0.0001), decreased amount of ascites (62.5% PBS vs. 25% CF33-hNIS-antiPLD1), and prolonged animal survival (p<0.01). Conclusions: CF33-OVs demonstrate effective antitumor activity and can deliver functional proteins in vitro and in vivo. CF33-hNIS-antiPDL1 treatment induced sustained regression of GCPC and prolonged survival. These promising preclinical results support peritoneal-directed strategies with CF33-hNIS-antiPDL1 in GCPC patients.

Ex vivo oncolytic and immune activity of CF33-hNIS-antiPDL1 against fresh peritoneal cells from patients with gastric cancer with and without peritoneal metastases

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Background: No effective therapy exists for peritoneal metastases (PM) from gastric cancer (GC), which remain fatal within months of diagnosis. We investigated a novel chimeric oncolytic virus platform, CF33-OV, for its anti-cancer potential against peritoneal cancer cells from GC patients. Methods: We prospectively collected fresh ascites or peritoneal washings from 30 GC patients between 2019 and 2020. These included 16 males (53.3%) and 14 females (46.7%) with a mean age of 51.3 ± 15.1 years. Of the 30 patients, 23 (90%) had cytology or biopsy-proven PM. Cells isolated from the peritoneal fluid were analyzed using flow cytometry for immune cell markers and/or treated with PBS, CF33-GFP (MOI=3), or CF33-hNIS-antiPDL1 (MOI=3) for 15 hours. We evaluated the treated cells for virus infection, replication, CD8+ and CD4+ expression with exhaustion markers, virus infection, replication, and cytotoxicity. We evaluated ex vivo CD274 (PD-L1) blockade by virus-encoded anti-PD-L1 scFv and the release of growth factors and cytokines following CF33-hNIS-antiPDL1 treatment. Results: The CD45- cancer cell percentage was higher, and the CD8+ T cell percentage was significantly lower in the ascites group than in the peritoneal washing group. At baseline, low levels of CD274 (PD-L1), CD252 (OX40L), and EGFR were identified on the surface of cancer cells. CD4+ and CD8+ T cells did not express cell surface exhaustion markers. After 15 hours of treatment, CF33-GFP infected, replicated in, and killed cancer cells ex vivo with a significantly higher dead cell percentage than the PBS control group (10.8% treated vs. 3.1% control, p-value <0.05). Of the live cancer cells, 69% were GFP+ by flow cytometry. Fluorescence microscopy results confirmed virus-encoded GFP expression in the ex vivo cells. Moreover, CF33-hNIS-antiPDL1 produced functional anti-PD-L1 scFv, which blocked phycoerythrin labeled anti-PD-L1 binding to PD-L1 on live cancer cells. Virus treatment increased CD8+CD107α+ and CD4+CD107α+ T cell percentages while decreasing the release of growth factors (EGF and PDGF) and inhibitory immune factors (soluble anti-PD-L1, GM-CSF, and IL-10). Conclusions: CF33-hNIS-antiPDL1 is oncolytic with immune-activating effects against GCPM ex vivo and has solid potential for intraperitoneal therapy of GCPM patients.

Simply structured polarization-independent high efficiency multilayer dielectric gratings

A polarization-independent multilayer dielectric diffraction grating with a low aspect ratio and high diffraction efficiency was designed and fabricated. The diffraction grating designed with a grating density of 1200 lines/mm had an aspect ratio of 0.59, mean polarization-independent diffraction efficiency in the Littrow angle of ±2.5^∘, and 1030-1080 nm wavelength range of 97.2%. The designed grating was fabricated using ion assisted deposition and reactive ion etching techniques. The mean polarization-independent diffraction efficiency of the fabricated grating was 96.1%, and its standard deviation was 0.68%. The fabricated diffraction grating was irradiated with a 1064 nm cw laser, with a power density of 30kW/cm², for 1 min to measure the temperature change before and after the laser application. It was verified that the temperature variation of the diffraction grating without heat treatment was 8.8°C, and the temperature variation after heat treatment at 400°C decreased to 2.3°C.

CF33-hNIS-antiPDL1 virus primes pancreatic ductal adenocarcinoma for enhanced anti-PD-L1 therapy

Immunotherapeutic strategies that combine oncolytic virus (OV) and immune checkpoint inhibitors have the potential to overcome treatment resistance in pancreatic ductal adenocarcinoma (PDAC), one of the least immunogenic solid tumors. Oncolytic viral chimera, CF33-hNIS-antiPDL1 genetically modified to express anti-human PD-L1 antibody and CF33-hNIS-Δ without the anti-PD-L1 gene, were used to investigate the immunogenic effects of OVs and virus-delivered anti-PD-L1 in PDAC in vitro. Western blot, flow cytometry, and immunofluorescence microscopy were used to evaluate the effects of CF33-hNIS-Δ and IFNγ on PD-L1 upregulation in AsPC-1 and BxPC-3 cells, and CF33-hNIS-antiPDL1 production of anti-PD-L1 and surface PD-L1 blockade of AsPC-1 and BxPC-3 with or without cocultured activated T cells. The cytosolic and cell surface levels of PD-L1 in PDAC cell lines varied; only BxPC-3 showed high cell surface expression. Treatment of these cells with CF33-hNIS-Δ and IFNγ significantly upregulated PD-L1 expression and translocation of PD-L1 from the cytosol onto the cell surface. Following coculture of activated T cells and BxPC-3 with CF33-hNIS-antiPDL1, the cell surface PD-L1 blockade on BxPC-3 cells by virus-delivered anti-PD-L1 antibody increased granzyme B release and prevented virus-induced decrease of perforin release from activated CD8+ T cells. Our results suggest that CF33-IOVs can prime immune checkpoint inhibition of PDAC and enhance antitumor immune killing.

Priming stroma with a vitamin D analog to optimize viroimmunotherapy for pancreatic cancer

Pancreatic cancer resistance to immunotherapies is partly due to deficits in tumor-infiltrating immune cells and stromal density. Combination therapies that modify stroma and recruit immune cells are needed. Vitamin D analogs such as calcipotriol (Cal) decrease fibrosis in pancreas stroma, thus allowing increased chemotherapy delivery. OVs infect, replicate in, and kill cancer cells and recruit immune cells to immunodeficient microenvironments. We investigated whether stromal modification with Cal would enhance oncolytic viroimmunotherapy using recombinant orthopoxvirus, CF33. We assessed effect of Cal on CF33 replication using pancreas ductal adenocarcinoma (PDAC) cell lines and in vivo flank orthotopic models. Proliferation assays showed that Cal did not alter viral replication. Less replication was seen in cell lines whose division was slowed by Cal, but this appeared proportional to cell proliferation. Three-dimensional in vitro models demonstrated decreased myofibroblast integrity after Cal treatment. Cal increased vascular lumen size and immune cell infiltration in subcutaneous models of PDAC and increased viral delivery and replication. Cal plus serial OV dosing in the syngeneic Pan02 model caused more significant tumor abrogation than other treatments. Cal-treated tumors had less dense fibrosis, enhanced immune cell infiltration, and decreased T cell exhaustion. Calcipotriol is a possible adjunct for CF33-based oncolytic viroimmunotherapy against PDAC.

A comprehensive preclinical study supporting clinical trial of oncolytic chimeric poxvirus CF33-hNIS-anti-PD-L1 to treat breast cancer

CF33-hNIS-anti-PD-L1 is an oncolytic chimeric poxvirus encoding two transgenes: human sodium iodide symporter and a single-chain variable fragment against PD-L1. Comprehensive preclinical pharmacology studies encompassing primary and secondary pharmacodynamics and biodistribution and safety studies were performed to support the clinical development of CF33-hNIS-anti-PD-L1. Most of the studies were performed in triple-negative breast cancer (TNBC) models, as the phase I trial is planned for patients with TNBC. Biological functions of virus-encoded transgenes were confirmed, and the virus demonstrated anti-tumor efficacy against TNBC models in mice. In a good laboratory practice (GLP) toxicology study, the virus did not produce any observable adverse effects in mice, suggesting that the doses proposed for the clinical trial should be well tolerated in patients. Furthermore, no neurotoxic effects in mice were seen following intracranial injection of the virus. Also, the risk for horizontal transmission of CF33-hNIS-anti-PD-L1 was assessed in mice, and our results suggest that the virus is unlikely to transmit from infected patients to healthy individuals. Finally, the in-use stability and compatibility of CF33-hNIS-anti-PD-L1 tested under different conditions mimicking the clinical scenarios confirmed the suitability of the virus in clinical settings. The results of these preclinical studies support the use of CF33-hNIS-anti-PD-L1 in a first-in-human trial in patients with TNBC.

PET imaging and treatment of pancreatic cancer peritoneal carcinomatosis after subcutaneous intratumoral administration of a novel oncolytic virus, CF33-hNIS-antiPDL1

Peritoneal carcinomatosis of gastrointestinal malignancies remains fatal. CF33-hNIS-antiPDL1, a chimeric orthopoxvirus expressing the human sodium iodide symporter (hNIS) and anti-human programmed death-ligand 1 antibody, has demonstrated robust preclinical activity against pancreatic adenocarcinoma (PDAC). We investigated the ability of CF33-hNIS-antiPDL1 to infect, help detect, and kill peritoneal tumors following intratumoral (i.t.) injection of subcutaneous (s.c.) tumors in vivo. Human PDAC AsPC-1-ffluc cells were inoculated in both the s.c. space and the peritoneal cavity of athymic mice. After successful tumor engraftment, s.c. tumors were injected with CF33-hNIS-antiPDL1 or PBS. We assessed the ability of CF33-hNIS-antiPDL1 to infect, replicate in, and allow the imaging of tumors at both sites (immunohistochemistry [IHC] and ¹²⁴I-based positron emission tomography/computed tomography [PET/CT] imaging), tumor burden (bioluminescence imaging), and animal survival. IHC staining for hNIS confirmed expression in s.c. and peritoneal tumors following virus treatment. Compared to the controls, CF33-hNIS-antiPDL1-treated mice showed significantly decreased s.c. and peritoneal tumor burden and improved survival (p < 0.05). Notably, 2 of 8 mice showed complete regression of disease. PET/CT avidity for ¹²⁴I uptake in s.c. and peritoneal tumors was visible starting at day 7 following the first i.t. dose of CF33-hNIS-antiPDL1. We show that CF33-hNIS-antiPDL1 can help detect and kill both s.c. and peritoneal tumors following s.c. i.t. treatment.

Toward comprehensive imaging of oncolytic viroimmunotherapy

Oncolytic viruses infect, replicate in, and kill cancer cells, leaving normal cells unharmed; they also recruit and activate immune cells against tumor cells. While clinical indications for viroimmunotherapy are growing, barriers to widespread treatment remain. Ensuring real-time tracking of viral replication and resulting anti-tumor immune responses will overcome some of these barriers and is thus a top priority. Clinically optimizing trackability of viral replication will promote safe dose increases, guide serial dosing, and enhance treatment effects. However, viral delivery is only half the story. Oncolytic viruses are known to upregulate immune checkpoint expression, thereby priming otherwise immunodeficient tumor immune microenvironments for treatment with checkpoint inhibitors. Novel modalities to track virus-induced changes in tumor microenvironments include non-invasive measurements of immune cell populations and responses to viroimmunotherapy such as (1) in situ use of radiotracers to track checkpoint protein expression or immune cell traffic, and (2) ex vivo labeling of immune cells followed by nuclear medicine imaging. Herein, we review clinical progress toward accurate imaging of oncolytic virus replication, and we further review the current status of functional imaging of immune responses to viroimmunotherapy.

Abstract 1155: Subcutaneous intratumoral administration of a novel oncolytic virus leads to eradication of peritoneal disseminated pancreatic cancer in nude mice

Introduction: We investigated a novel oncolytic virus, CF33-hNIS-antiPDL1, which has shown robust preclinical activity against numerous solid tumors, for its ability to track and kill distant peritoneal metastases after local virus administration in vivo.

Methods: In this study, we used CF33-hNIS-antiPDL1, a replication competent orthopoxviral chimera engineered to express the human sodium iodine symporter (hNIS) and anti-human programmed death ligand 1 (PD-L1) antibody. To create our mouse model, we inoculated the human pancreatic cell line - AsPC1-ffluc (5x106 cells/site) in both the subcutaneous space and the peritoneum in nude mice. After confirming presence of tumor, the mice were divided into two groups; and treated with either 1) three doses of intratumoral (IT) CF33-hNIS-antiPDL1 (3x105 plaque forming units; (n=8) or 2) PBS (n=4). Each mouse was assessed for the following: tumor burden (bioluminescence imaging); CF33-hNIS-antiPDL1 tracking and replication in tumors (124I based PET imaging); and survival (time to death).

Results: By week 2, the animals in the CF33-hNIS-antiPDL1 treated group compared to the PBS treated group had significantly decreased tumor burden both in the peritoneal tumors (2.5e9±2.498e9 %/ID/cc versus 1.6e10 ±1.3e10 %/ID/cc, respectively; p&lt;0.05) and SC tumors (5.2e8 ±4.3e8 %/ID/cc versus 2.6e9 ±2.6e9 %/ID/cc; p&lt;0.05). With a median survival of 35 days, all PBS treated mice died from disease between 21 to 47 days. In the CF33-hNIS-antiPDL1 treated group, the median survival was 49 days; and two out of eight mice were still alive at 220 days (p&lt;0.05). These two surviving animals had no evidence of cancer; there was complete eradication of SC and peritoneal tumors. At one week after the first CF33-hNIS-antiPDL1 administration, significantly increased PET avidity for 124I uptake in the SC tumors (6.4±1.5 photons/second of regions of interest) and PC tumors (3.5±0.14 photons/second of regions of interest) were visible in the CF33-hNIS-antiPDL1 treated mice.

Conclusion: After local SC tumor injection, CF33-hNIS-antiPDL1 can efficiently kill local tumor and kill distant peritoneal metastases to improve survival. Successful therapy of SC and peritoneal tumors using CF33-hNIS-antiPDL1 can be visualized by 124I-based PET imaging.

Citation Format: Zhifang Zhang, Annie Yang, Shyambabu Chaurasiya, Sang-In Kim, Anthony K. Park, Jianming Lu, Susanne G. Warner, Yuman Fong, Yanghee Woo. Subcutaneous intratumoral administration of a novel oncolytic virus leads to eradication of peritoneal disseminated pancreatic cancer in nude mice [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1155.

Effective combination immunotherapy using oncolytic viruses to deliver CAR targets to solid tumors

Chimeric antigen receptor (CAR)-engineered T cell therapy for solid tumors is limited by the lack of both tumor-restricted and homogeneously expressed tumor antigens. Therefore, we engineered an oncolytic virus to express a nonsignaling, truncated CD19 (CD19t) protein for tumor-selective delivery, enabling targeting by CD19-CAR T cells. Infecting tumor cells with an oncolytic vaccinia virus coding for CD19t (OV19t) produced de novo CD19 at the cell surface before virus-mediated tumor lysis. Cocultured CD19-CAR T cells secreted cytokines and exhibited potent cytolytic activity against infected tumors. Using several mouse tumor models, delivery of OV19t promoted tumor control after CD19-CAR T cell administration. OV19t induced local immunity characterized by tumor infiltration of endogenous and adoptively transferred T cells. CAR T cell-mediated tumor killing also induced release of virus from dying tumor cells, which propagated tumor expression of CD19t. Our study features a combination immunotherapy approach using oncolytic viruses to promote de novo CAR T cell targeting of solid tumors.

EVALUATION OF INTERNAL EXPOSURE TO RADIOACTIVE AEROSOL GENERATED FROM PLASMA MELTING SYSTEM USING THE BIDAS CODE

The radioactive aerosol generated by the Nuclear Power Plant (NPP) decommissioning process can be inhaled by workers and deposited inside the human body, resulting in internal exposure. Because internal exposure, unlike external exposure, is difficult to measure directly, it is all the more necessary to assess the dose workers receive as a result of internal exposure. Precise assessment of the internal exposure necessitates actual measurements in the work environment such as the workers' respiration rate, kind of nuclide and amount of captured nuclide. However, in the event of difficulties in securing these measurements, the internal exposure dose can be estimated based upon the recommended values by the ICRP (International Commission on Radiological Protection) such as the intake fraction and particle size. In this study, 5 μm was selected as the particle size as recommended by the ICRP, and both heavy and light respiratory rates were used in the calculation. With respect to the nuclides contained in the radioactive aerosol and their concentrations, the data captured for the aerosol in the melting facility on the Kozloduy NPP premises in Bulgaria were applied to estimate workers' internal exposure. As a result, each worker was found not to have received more than 20 mSv/yr, which is the maximum annual permissible dose for workers.

Role of surgery and hyperthermic intraperitoneal chemotherapy in ovarian cancer

Ovarian cancer is one of the deadliest gynaecological malignancies and tends to be diagnosed at an advanced stage. Similar to many malignancies, surgery plays a critical role in many aspects of ovarian cancer management. Hyperthermic intraperitoneal chemotherapy (HIPEC) involves the induction of hyperthermia and delivery of intraperitoneal chemotherapy directly into the peritoneal cavity. Combined with cytoreductive surgery, HIPEC is an emerging treatment modality for ovarian cancer. Ovarian cancer survival outcomes can be improved by treatment with surgery and HIPEC in selected patients. Thus, this study aimed to review the current role of surgery and HIPEC in epithelial ovarian cancer. Evidence from the monumental and recent literature will be introduced.

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Surgery plays a critical role in many aspects of ovarian cancer management.

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Combined with cytoreductive surgery, HIPEC is an emerging modality for ovarian cancer.

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Improvement of survival outcomes is expected by applying individualised surgery and HIPEC for each ovarian cancer patient.

The epigenetic DNA modification 5-carboxylcytosine promotes high levels of cyclobutane pyrimidine dimer formation upon UVB irradiation

In mammals, DNA methyltransferases create 5-methylcytosines (5mC) predominantly at CpG dinucleotides. 5mC oxidases convert 5mC in three consecutive oxidation steps to 5-hydroxymethylcytosine (5hmC), 5-formylcytosine (5fC) and then 5-carboxylcytosine (5caC). Upon irradiation with UV light, dipyrimidines containing C, 5mC and 5hmC are known to form cyclobutane pyrimidine dimers (CPDs) as major DNA photolesions. However, the photobiology of 5fC and 5caC has remained largely unexplored. Here, we tested a series of oligonucleotides with single or multiple positions carrying cytosine (C), 5mC, 5hmC, 5fC or 5caC and irradiated them with different sources of UV irradiation. While UVC radiation produced CPDs near dipyrimidines containing all types of modified cytosine bases, UVB radiation produced by far the highest levels of CPDs near 5caC-containing sequences. Dipyrimidines one or two nucleotide positions adjacent to 5caC but not always those involving this modified base directly were the major sites for these prominent UVB photoproducts. This selectivity did not depend on whether 5caC was present on one or both DNA strands at CpG sequences. We also observed a tendency of the 5caC-containing DNA strands to undergo apparent covalent crosslinking. This reaction occurred with UVB or UVC but not with UVA irradiation. Our data show that 5-carboxylcytosine, although generally a rare base in the genome, can nonetheless make a strong contribution to sequence-specific DNA damage perhaps by acting as a DNA-intrinsic photosensitizer.

Recombinant Orthopoxvirus Primes Colon Cancer for Checkpoint Inhibitor and Cross-Primes T Cells for Antitumor and Antiviral Immunity

Although it is known that oncolytic viruses can inflame and recruit immune cells to otherwise immunosuppressed tumor microenvironments, the influence of the antiviral immune response on antitumor immunity is less clear across viral platforms and tumor types. CF33 is a recombinant orthopoxvirus backbone effective against colon cancer. We tested derivatives of CF33 with and without immune-checkpoint inhibition (anti-PD-L1) in mouse models of colon cancer. Results showed that the efficacy of CF33 backbone with J2R deletion (single-deleted) against colon cancer is not altered by additional deletion of F14.5L in vitro or in vivo CF33 infection upregulated PD-L1 expression on tumor cells and led to an increased influx of lymphocytes and macrophages in tumors. Also, the levels of active CD8⁺ (IFNγ⁺) T cells in the virus-treated tumors were higher than those in control-treated tumors. Furthermore, a combination of CF33 derivatives with anti-PD-L1 resulted in durable tumor regression and long-term survival, resistant to tumor rechallenge. Analysis of immune cells from the treated mice showed that tumor-specific T cell activation occurred more robustly in tumors treated with the virus and that T cells were more strongly activated against the virus than against tumor, in an MHC-I-dependent manner. Our findings warrant further studies on the role of cross-priming of T cells against viral and tumor antigens, in the overall success of viroimmunotherapy.

Effective combination immunotherapy using oncolytic viruses to deliver CAR targets to solid tumors

An effective combination immunotherapy using oncolytic viruses delivers de novo CD19 to promote CD19-CAR T cell therapy against solid tumors in mice.

Complete mitochondrial genome of two shorebirds (Charadriiformes: Scolopacidae), great knot (Calidris tenuirostris) and bar-tailed godwit (Limosa lapponica)

The mitochondrial genome of Calidris tenuirostris and Limosa lapponica were described using the whole mitochondrial genome obtained from Illumina Next-Generation Sequencing (NGS) technology. Total length of the mitogenome of C. tenuirostris was 16,732bp with slight A+T bias (55.3%). Genome size of L. lapponica was 16,773bp long and A+T biased (56.3%). Both gemones consisting of 2 rRNAs, 13 protein-coding genes, 22 tRNA genes and 1 non-coding regions. This is the first report of complete mitogenomes of these two shorebird species, (C. tenuirostris and of L. lapponica). We observed paraphyletic relationship among the species in the Family Scolopacidae. Also our result showed analogous patterns with the previous studies on the parallel relationships of shorebird species. This study provides basic genetic information for help in understanding phylogenetic relationships . within the Charadriiformes.

Oncolytic poxvirus CF33-hNIS-ΔF14.5 favorably modulates tumor immune microenvironment and works synergistically with anti-PD-L1 antibody in a triple-negative breast cancer model

Triple-negative breast cancer is the most aggressive subtype of breast cancer and is difficult to treat. Breast cancer is considered to be poorly immunogenic and hence is less responsive to immunotherapies. We tested whether the oncolytic poxvirus CF33-hNIS-ΔF14.5 could modulate tumor immune microenvironment and make the tumors responsive to the immune checkpoint inhibitor anti-PD-L1. We found that virus infection causes the upregulation of PD-L1 levels on triple-negative breast cancer cells in vitro as well as in vivo in mice. In a mouse model of orthotopic triple-negative breast cancer, the virus was found to increase tumor infiltration by CD8+ T cells. Likewise, in mice treated with CF33-hNIS-ΔF14.5 high levels of proinflammatory cytokines IFNγ and IL-6 were found in the tumors but not in the serum. The levels of immune modulation were even higher in mice that were treated with a combination of the virus and anti-PD-L1 antibody. While CF33-hNIS-ΔF14.5 and anti-PD-L1 antibody failed to exert significant anti-tumor effect as a single agent, a combination of the two agents resulted in significant anti-tumor effect with 50% mice experiencing complete tumor regression when both agents were injected intra-tumorally. Furthermore, the ‘cured’ mice did not develop tumor after re-challenge with the same cancer cells suggesting that they developed immunity against those cancer cells. Taken together, our study shows that CF33-hNIS-ΔF14.5 favorably modulates tumor immune microenvironment in triple-negative breast cancer model making them responsive to the immune checkpoint inhibitor anti-PD-L1, and hence warrants further studies to determine the clinical applicability of this combination therapy.

Spinal epidural hematoma occurring at a distance from the transforaminal epidural injection site: A case report

RATIONALE

Transforaminal epidural steroid injection (TFESI) is a conservative method to treat back pain due to radiculopathy. However, epidural hematoma can occur after the procedure by various mechanisms, which can cause serious complications.

PATIENT CONCERNS

An 82-year-old man with spinal stenosis was treated with TFESI in the right intervertebral foramen at the L2-L3 level. The next morning, he experienced severe back pain and diffuse motor deficit.

DIAGNOSIS

Emergency magnetic resonance imaging revealed fluid collection in the posterior epidural space at the T11-L1 level with central-canal stenosis.

INTERVENTIONS

Emergency hematoma evacuation was performed to remove the epidural hematoma.

OUTCOMES

After the surgery, the back pain disappeared.

LESSONS

Epidural hematoma may occur due to causes other than direct needle injury after TFESI. Therefore, careful observation of the patient is necessary after the procedure.

A chimeric poxvirus with J2R (thymidine kinase) deletion shows safety and anti-tumor activity in lung cancer models

Oncolytic viruses have shown excellent safety profiles in preclinical and clinical studies; however, in most cases therapeutic benefits have been modest. We have previously reported the generation of a chimeric poxvirus (CF33), with significantly improved oncolytic characteristics, through chimerization among different poxviruses. Here we report the sequence analysis of CF33 and oncolytic potential of a GFP-encoding CF33 virus (CF33-GFP) with a J2R deletion in lung cancer models. Replication of CF33-GFP and the resulting cytotoxicity were higher in cancer cell lines compared to a normal cell line, in vitro. After infection with virus, cancer cells expressed markers for immunogenic cell death in vitro. Furthermore, CF33-GFP was safe and exerted potent anti-tumor effects at a dose as low as 1000 plaque forming units in both virus-injected and un-injected distant tumors in A549 tumor xenograft model in mice. Likewise, in a syngeneic model of lung cancer in mice, the virus showed significant anti-tumor effect and was found to increase tumor infiltration by CD8+ T cells. Collectively, these data warrant further investigation of this novel chimeric poxvirus for its potential use as a cancer bio-therapeutic.

A Novel Chimeric Poxvirus Encoding hNIS Is Tumor-Tropic, Imageable, and Synergistic with Radioiodine to Sustain Colon Cancer Regression

Colon cancer has a high rate of recurrence even with good response to modern therapies. Novel curative adjuncts are needed. Oncolytic viral therapy has shown preclinical promise against colon cancer but lacks robust efficacy in clinical trials and raises regulatory concerns without real-time tracking of viral replication. Novel potent vectors are needed with adjunctive features to enhance clinical efficacy. We have thus used homologous recombination and high-throughput screening to create a novel chimeric poxvirus encoding a human sodium iodide symporter (hNIS) at a redundant tk locus. The resulting virus (CF33-hNIS) consistently expresses hNIS and demonstrates replication efficiency and immunogenic cell death in colon cancer cells in vitro. Tumor-specific CF33-hNIS efficacy against colon cancer results in tumor regression in vivo in colon cancer xenograft models. Early expression of hNIS by infected cells makes viral replication reliably imageable via positron emission tomography (PET) of I-124 uptake. The intensity of I-124 uptake mirrors viral replication and tumor regression. Finally, systemic delivery of radiotherapeutic I-131 isotope following CF33-hNIS infection of colon cancer xenografts enhances and sustains tumor regression compared with virus treatment alone in HCT116 xenografts, demonstrating synergy of oncolytic viral therapy with radioablation in vivo.

Abstract P3-03-31: Is sentinel lymph node biopsy necessary in all patients with early breast cancer?

Background and objectives : Since the results of the American College of Surgeons Oncology Group Z0011 published, the criteria for applying axillary lymph node (ALN) dissection was relaxed among early breast cancer patients who were scheduled for breast conserving surgery, adjuvant chemotherapy therapy, and adjuvant radiation therapy. SLNB criteria may be established if pathologic nodal status can be predicted. The aim of this study was to develop a nomogram for preoperative prediction of axillary node metastasis.

Methods: The records of 1650 patients with T1, T2 primary invasive breast cancer who were treated between January 2013 and September 2016 were selected from the medical database of Yonsei University (Seoul, South Korea). Those whom a preoperative diagnosis of axillary node metastases were excluded. Two nomogram that predicted three or more axillary metastasis and one or more axillary metastasis were developed using a binary logistic regression model with a training cohort. Internal validation was carried out adopting bootstrap method by validation cohort 500 times resampling.

Result: A total of 82 (4.8%) patients had three or more ALNs metastasis. Three hundred seventy five (17.4%) patients had one or more ALNs metastasis. Axillary metastasis was associated with Preoperative ALN suspicious image findings, clinical tumor size, Number of neoplastic foci, estrogen receptor status, Ki-67 expression, tumor marker. The nomogram was developed based on the clinical and statistically significant predictors. It had good discrimination performance (AUC 0.79, 95% CI, 0.73–0.85), (AUC 0.71, 95% CI, 0.67–0.74) and calibration fit.

Conclusion:Our nomogram might help predict the ALN metastasis in breast cancer patients. Patients with a low probability of ALN metastasis could be spared SLNB.

Citation Format: Yoon KH, Lee KB, Lee H, Lee J, Kim JY, Park HS, Park S, Kim SI, Cho YU, Park B-W. Is sentinel lymph node biopsy necessary in all patients with early breast cancer? [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 P3-03-31.

Abstract OT2-01-03: A prospective pilot study of simultaneous robotic assisted nipple sparing mastectomy and immediate reconstruction

Endoscopic breast surgery was expected to be an adequate technique to complete cancer clearance and preservation of the patient's body image. However, this technique has limitations including incomplete internal movements and unstable vision of a two dimensional camera due to inflexible endoscopic instruments especially during the skin flap formation. High resolution, ten-fold image magnification, and three-dimensional optics of robotic surgery help overcome the limitations of endoscopic surgery, and thus robotic surgery has been adopted in a wide range of intracorporeal procedures including breast surgery. However, few studies have evaluated feasibility and safety of robotic assisted nipple sparing mastectomy (RANSM) and immediate breast reconstruction (IBR) for the treatment of breast cancer. There were not any investigation to assess patients' satisfaction of cosmetic effect after performing RANSM and IBR. This study is aim to verify the feasibility and the safety of RANSM and IBR and to analyze cosmetic effect of the procedure and satisfaction of patients. The target number of enrollments is 15 patients. Patients who are diagnosed with early breast cancer or BRCA 1/2 mutation carriers are enrolled. Female patients over 20 years old who are candidates to preserve nipple areolar complex and considered to perform reconstruction with implants are prospectively collected. Written informed consents are mandatory. Patients who are considered the high possibility of postoperative radiation therapy according to preoperative stage are not included in this study. We exclude patients who want to undergo other methods of breast reconstruction than breast reconstruction with implants. Patients will undergo RANSM and IBR through a single axillary skin incision simultaneously. Regular follow-up at 1 month and 6 months after RANSM and IBR is scheduled to record recovery of a patient, amount of a drain, date of drain removal, and postoperative complications. Patient satisfaction questionnaire will be completed on the last follow-up day. To evaluate the safety of robotic assisted surgery, the oncologic safety (margin status of nipple areolar complex), postoperative recovery of a patient, and postoperative complications are investigated. We compare preoperative and postoperative 6 month photographs of patients and estimate the surgical outcome by objective indicators to evaluate the cosmetic grading by plastic surgeons. Patients' satisfaction are assessed by questionnaire (BREAST-Q) at the 6-month visit.

Citation Format: Lee J, Park HS, Kim JH, Lee DW, Song SY, Lew DH, Kim JY, Kim SI, Cho YU, Lee H, Lee KB, Yoon KH. A prospective pilot study of simultaneous robotic assisted nipple sparing mastectomy and immediate reconstruction [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 OT2-01-03.

Acquisition of Carbapenemase-Producing Enterobacteriaceae in Solid Organ Transplantation Recipients

BACKGROUND

Carbapenemase-producing Enterobacteriaceae (CPE) can lead to life-threatening outcomes with rapid spread of the carbapenemase gene in solid organ transplantation (SOT) recipients because of limitations of available antibiotics. We examined the characteristics and importance of CPE acquisition in SOT recipients with large numbers of CPE isolates.

METHODS

Between November 2015 and October 2016, 584 CPE isolates were found in 37 recipients and verified by carbapenemase gene multiplex polymerase chain reaction (PCR). One hundred recipients with at least 2 negative results in carbapenemase PCR for stool surveillance and no CPE isolates in clinical samples were retrospectively included.

RESULTS

Most CPE isolates were Klebsiella pneumoniae carbapenemase (KPC)-producing K. pneumoniae (546, 93.5%). The most frequent transplantation organ was lung (43.3%), and the most common sample with CPE isolates other than stool was respiratory tract (22.6%). The median time between SOT and first CPE acquisition was 7 days. All-cause mortality was significantly higher in recipients with CPE than in those without CPE (24.3% vs 10.0%; P = .03). In multivariate regression analysis, stool colonization of vancomycin-resistant Enterococci and/or Clostridium difficile during 30 days before SOT (odds ratio [OR], 3.28; 95% CI, 1.24-8.68; P = .02), lung transplantation (OR, 4.50; 95% CI, 1.19-17.03; P = .03), and intensive care unit stay ≥2 weeks (OR, 6.21; 95% CI, 1.72-22.45; P = .005) were associated with acquisition of CPE.

CONCLUSIONS

Early posttransplantation CPE acquisition may affect the clinical outcome of SOT recipients. Careful screening for CPE during the early posttransplantation period would be meaningful in recipients with risk factors.

Impact of Cigarette Smoking on Living Kidney Donors

BACKGROUND

Smoking is known to result in a decline in renal allograft function and survival of recipients; however, the effect of smoking on living kidney donors remains unknown. In this study we evaluated the impact of cigarette smoking on renal function of kidney donors.

METHODS

Among 1056 donors who underwent nephrectomy, 612 completed the 6-month follow-up protocol and were enrolled in the study. The association of smoking status, including pack-years smoking history, and postoperative renal function was evaluated.

RESULTS

Among donors, 68.1% had never smoked, 8% were former smokers, and 23.9% were current smokers. Donors who never smoked were older than former and current smokers (42.3 ± 11.8, 41.9 ± 11.1, and 38.3 ± 10.9 years, respectively; P < .001). There was no difference in preoperative renal function between groups; however, postoperative estimated glomerular filtration rate (eGFR) was lower in former and current smokers than in those who never smoked (64.6 ± 13.8, 64.7 ± 12.3, and 67.8 ± 13.1 mL/min/1.73 m², respectively; P = .023). In former and current smokers, pack-years smoking history was negatively associated with pre- and postoperative eGFR (r = -0.305 and -0.435, P < .001), and correlated with postoperative percent eGFR decline (r = 0.248, P < .001). Smoking history was associated with postoperative development of chronic kidney disease (CKD). Especially in former smokers, a smoking history of more than 12 pack-years was strongly associated with development of CKD (odds ratio = 7.5, P = .003).

CONCLUSION

Even if they no longer smoke, donors with a smoking history require close observation due to increased risk of CKD development after kidney donation. A detailed pack-years smoking history should be obtained, and smoking cessation strategies should be implemented in kidney donors.

Clinical Significance of Macrophage Polarization in Antibody-Mediated Rejection of Renal Allograft

BACKGROUND

The significance of proinflammatory M1 (classically activated) and profibrotic M2 (alternatively activated) macrophages in antibody-mediated rejection (ABMR) after kidney transplantation has not been investigated.

METHODS

Fifty-five biopsy-confirmed ABMR samples were stained with MRP 8/14 (a marker of M1 macrophages) and CD163 (a marker of M2 macrophages), and positive cells were counted in glomeruli and the tubulointerstitium, respectively. Patients were classified into M1 and M2 polarization groups according to the glomerular and tubulointerstitial M1:M2 ratio, and the results were compared with Banff scores, serum creatinine level, estimated glomerular filtration rate (eGFR), and graft survival.

RESULTS

The glomerular M2 polarization group showed significantly higher chronic glomerulopathy scores, serum creatinine levels, and lower eGFR at the time of biopsy (P = .019 and P = .015, respectively) and 3-month postbiopsy (P = .016 and P = .032, respectively) than the M1 polarization group. The tubulointerstitial M2 polarization group had significantly lower glomerulitis, arteritis, peritubular capillaritis, and glomerulitis + peritubular capillaritis scores than the M1 polarization group, but there was no significant difference in renal function. Long-term graft survival was not associated with macrophage polarization.

CONCLUSION

Glomerular M2 polarization in ABMR biopsy samples is associated with chronic glomerular injury and poorer graft function, but without graft survival.

Impact of Pretransplant Infections on Clinical Course in Liver Transplant Recipients

BACKGROUND

Uncontrolled infections are known to be an absolute contraindication for liver transplantation; however, the posttransplant prognosis of recipients treated for pretransplant infection is unclear. The aim of this study was to analyze pretransplant infections among liver transplant recipients and to determine their impact on posttransplant clinical outcomes.

METHODS

This study retrospectively analyzed 357 subjects who had undergone living-donor liver transplantation between January 2008 and May 2014.

RESULTS

Among 357 recipients, 71 patients (19.8%) had 74 episodes of infectious complications before liver transplantation. These complications consisted of pneumonia (n = 13), spontaneous bacterial peritonitis (n = 12), catheter-related infection (n = 10), urinary tract infection (n = 12), biliary tract infection (n = 6), and skin and soft-tissue infection (n = 3). Twenty-six patients experienced 29 episodes of bacteremia, and the most common pathogens were coagulase-negative staphylococci (n = 8), followed by Klebsiella pneumoniae (n = 7), Staphylococcus aureus (n = 4), and Streptococcus species (n = 3). Twenty-one bacteremic episodes (70%) occurred within 1 month before transplantation (n = 4). Recipients with pretransplant infections had significantly more frequent posttransplant infections (71.8% [51 of 71] vs 47.2% [35 of 286]; P = .0001), posttransplant bacteremia (33.8% [24 of 71] vs 20.3% [58 of 286]; P = .015), and longer posttransplant intensive care unit stays (11.2 ± 10.7 days vs 7.3 ± 4.2 days; P = .0004) than those without pretransplant infections. However, episodes of rejection (P = .36), length of hospitalization (P = .10), 28-day mortality (P = .31), and 1-year mortality (P = .61) after transplantation were not significantly different between the 2 groups.

CONCLUSIONS

Pretransplant infection had an impact on posttransplant morbidity, although not on rejection and mortality. Alertness for posttransplant infection and proper management (including effective antimicrobial coverage) would improve patient morbidity.

Seven-year Follow-up of Resin Infiltration Treatment on Noncavitated Proximal Caries

The purpose of this case report is to present success and failure outcomes of seven-year follow-up of resin infiltration treatment (RIT) used for the proximal caries of maxillary premolars. Although resin infiltration can be a good option for micro-invasive treatment, long-term follow-up data are not sufficient, and the outcome of this technique can be affected by factors such as technique sensitivity of procedure, patient's caries risk, and depth of caries progression. Therefore, careful case selection, application, and follow-up are needed.

Impact of Korea Network for Organ Sharing Expanded Donor Criteria on Delayed Graft Fuction in Kidney Transplantation: A Single-Center Experience

BACKGROUND

The shortage of donor organs has been a major challenge in transplantation. In an effort to reduce the donor shortage, kidney transplantation (KT) using expanded criteria donors (ECD) was encouraged. In Korea, transplantation centers used the Korea Network for Organ Sharing (KONOS) ECD criteria, which is different from the United Network for Organ Sharing (UNOS) criteria. The aim of this study is to evaluate the predictive power of KONOS criteria on delayed graft function (DGF) in comparison to UNOS criteria.

METHODS

A total of 376 recipients who underwent deceased donor kidney transplantation between January 2005 and December 2014 at Severance Hospital were retrospectively reviewed. Of these, 130 cases satisfied KONOS ECD, while the others followed KONOS standard criteria donor (SCD).

RESULTS

Donor age and history of hypertension was significantly higher with KONOS ECD than with KONOS SCD. In KONOS subgroup analysis, donor characteristics were different than with UNOS criteria. The incidence of DGF was higher in the KONOS ECD group than in the KONOS SCD group. However, UNOS ECD showed a high incidence of DGF compared to UNOS SCD with the same KONOS criteria. UNOS ECD was an independent risk factor for DGF in multivariate analysis. However, KONOS ECD was not a risk factor for DGF. Although glomerular filtration rate was inferior in the KONOS ECD group compared to the KONOS SCD group, the UNOS SCD group within the KONOS ECD group showed similar graft function compared to the KONOS SCD group.

CONCLUSION

KONOS criteria have a lower predictive power for DGF than UNOS criteria.

Novel oncolytic chimeric orthopoxvirus causes regression of pancreatic cancer xenografts and exhibits abscopal effect at a single low dose

Background

Pancreatic ductal adenocarcinoma (PDAC) has been increasing by 0.5% per year in the United States. PDAC portends a dismal prognosis and novel therapies are needed. This study describes the generation and characterization of a novel oncolytic chimeric orthopoxvirus for the treatment of pancreatic cancer.

Methods

After chimerization and high-throughput screening, CF33 was chosen from 100 new chimeric orthopoxvirus isolates for its ability to kill pancreatic cancer cells. In vitro cytotoxicity was assayed in six pancreatic cancer cell lines. In vivo efficacy and toxicity were evaluated in PANC-1 and MIA PaCa-2 xenograft models.

Results

CF33 caused rapid killing of six pancreatic cancer cells lines in vitro, releasing damage-associated molecular patterns, and regression of PANC-1 injected and non-injected distant xenografts in vivo after a single low intratumoral dose of 10³ plaque-forming units. Using luciferase imaging, CF33 was noted to preferentially replicate in tumors which corresponds to the low viral titers found in solid organs.

Conclusion

The low dose of CF33 required to treat pancreatic cancer in this preclinical study may ease the manufacturing and dosing challenges currently facing oncolytic viral therapy.

Endogenous Akt Activity Promotes Virus Entry and Predicts Efficacy of Novel Chimeric Orthopoxvirus in Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) is an aggressive subtype of breast cancer with high recurrence rate and poor prognosis. Here, we describe a novel, chimeric orthopoxvirus (CF33) that efficiently kills TNBC. Cytotoxicity was assayed in vitro in four TNBC cell lines. Viral replication was examined through standard plaque assay. Two orthotopic TNBC xenograft models were generated in athymic nude mice and were injected with CF33 intratumorally. CF33 was effective in vitro with potent cytotoxicity and efficient intracellular replication observed in TNBC lines with phosphatidylinositol 3-kinase (PI3K)/Akt pathway mutations that resulted in endogenous phospho-Akt (p-Akt) activity (BT549, Hs578T, and MDA-MB-468). Relative resistance to CF33 by wild-type PI3K/Akt pathway cell line MDA-MB-231 was overcome using higher MOI. The virus was effective in vivo with significant tumor size reduction in both xenograft models. Mechanistically, CF33 appears to share similar properties to vaccinia virus with respect to Akt-mediated and low-pH-mediated viral entry. In summary, CF33 demonstrated potent antitumoral effect in vitro and in vivo, with the most potent effect predicted by the presence of endogenous Akt activity in the TNBC cell line. Further investigation of its mechanism of action as well as genetic modifications to enhance its natural viral tropism are warranted for preclinical development.

A Novel Oncolytic Chimeric Orthopoxvirus Encoding Luciferase Enables Real-Time View of Colorectal Cancer Cell Infection

This study hypothesizes that a novel oncolytic chimeric orthopoxvirus CF33-Fluc is imageable and targets colorectal cancer cells (CRCs). A novel chimeric orthopoxvirus (CF33) was constructed. The thymidine kinase locus was replaced with firefly luciferase (Fluc) to yield a recombinant virus—CF33-Fluc. In vitro cytotoxicity and viral replication assays were performed. In vivo CRC flank xenografts received single doses of intratumoral or intravenous CF33-Fluc. Viral biodistribution was analyzed via luciferase imaging and organ titers. CF33-Fluc infects, replicates in, and kills CRCs in vitro in a dose-dependent manner. CF33 has superior secretion of extracellular-enveloped virus versus all but one parental strain. Rapid tumor regression or stabilization occurred in vivo at a low dose over a short time period, regardless of the viral delivery method in the HCT-116 colorectal tumor xenograft model. Rapid luciferase expression in virus-infected tumor cells was associated with treatment response. CRC death occurs via necroptotic pathways. CF33-Fluc replicates in and kills colorectal cancer cells in vitro and in vivo regardless of delivery method. Expression of luciferase enables real-time tracking of viral replication. Despite the chimerism, CRC death occurs via standard poxvirus-induced mechanisms. Further studies are warranted in immunocompetent models.

Abstract P2-05-07: Whole exome sequencing of extreme responders reveals low mutation burden in metastatic breast cancer

Background: Extreme responders to anticancer therapy are rarely encountered in the treatment of advanced breast cancer patients, but their treatment response have not been investigated on the whole exome level. We performed whole exome analysis to characterize genomic landscape of extreme responders in metastatic breast cancer patients.

Methods: Clinical samples were obtained from patients who showed exceptional response to anti-HER2 therapy or hormonal therapy. Non-responders were selected among those who did not respond. Matched breast tumor tissue (somatic DNA) and blood samples (germline DNA) were collected from a total of 18 responders (12 ER+, 6 HER2+) and 8 non-responders (6 ER+, 1 HER2+, 1 TNBC). Whole exome sequencing using Illumina HiSeq2500 was performed on the 26 patients (52 samples). Somatic single nucleotide variants (SNVs), indels and copy number variants (CNVs) were identified for each patient genome. Group specific somatic variants and mutation burden were statistically analyzed.

Findings: Cancer exomes were characterized by 1,455 somatic single-nucleotide variants (1,327 missense, 80 nonsense, 36 splice-site, 12 start/stop-lost), 149 insertions/deletions (108 frameshift, 41 inframe), with a median of 1 mutations per Mb (0.2 to 2.7 mutations per Mb) in all patients. Responders harbored a significantly lower non-synonymous mutation burden than non-responders (median, 27 vs. 90.5, P=0.01), and copy number variation burden was also lower (median 23 vs. 31, P=0.14). Multivariate analyses of factors influencing progression-free survival showed that high mutation burden and visceral metastases were significantly related with progression.

Interpretation: Extreme responders of metastatic breast cancer are characterized by low nonsynonymous mutational burden.

Citation Format: Sohn J, Lim SM, Kim E, Kim S, Koo JS, Kim SI, Park S, Park HS, Kwon N-J, Kim GM, Kim S. Whole exome sequencing of extreme responders reveals low mutation burden in metastatic breast cancer [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P2-05-07.

Abstract OT2-01-03: A prospective randomized study comparing surgery using electrosurgical bipolar sealing devices and surgery using conventional electro-cautery

Background: Seroma and lymphorrhea are the most common complication following mastectomy and/or axillary lymph node dissection (ALND). The manifestation of seroma accelerates complications such as post-operative bleeding, wound infection, prolonged recovery period. Sealing blood vessels and lymph drainages adequately during mastectomy and/or ALND may play a main role in reducing complication. Therefore, adequate sealing vessels and lymphatics during the surgery is important to reduce seroma and lymphorrhea related complications in patients with breast cancer. Objective: This study aims to show that electrosurgical bipolar sealing device for mastectomy could provide clinical benefit in reducing seroma formation. Design: ELBCE (ELectrosurgical Bipolar Devices VS Convention Electronicautery, NCT03166384)is a prospective, randomized, two-arm assignment controlled trial of application of electrosurgical bipolar sealing device for mastectomy in patients with breast cancer. Patients is randomized in 1:1 ratio to conventional suture and tie group or electrosurgical bipolar sealing devices group. Randomization is performed using opening sealed envelope before enrollment. The primary end point is to compare the total drainage volume until drain tube removal. The time to drain removal is also measured. The secondary end points is the total amount of aspiration from seroma after drain tube removal, and the frequency of seroma aspiration. Statistical consideration: A sample size 44 subjects per each arm was planned to provide a 90% power to detect a 25% decrease of the total amount of drainage fluid after surgery by using an electrosurgical bipolar sealing device when compared to a conventional suture and tie technique. In our experience, the average total volume of fluid after conventional suture and tie technique is 220 mL, with a standard deviation of 80. Eligibility criteria:Inclusion criteria are patients older than 20 years and those who planned to undergo total mastectomy and/or ALND. Exclusion criteria are bilateral breast cancer patients, male patients, patients who underwent ipsilateral axillar surgery or radiation therapy, recurrent breast cancer patients, patients without drain catheter, and patients with ductal carcinoma in situ who have not undergone ipsilateral sentinel lymph node biopsy or ALND.Present accrual and target accrual:ELSEBA study has an accrual target of 88 patients. To date, 8 patients have been randomized. Contact information:Dr. Hyung Seek Park, E-mail: hyungseokpark.md@gmail.com; imgenius@yuhs.ac, Telephone: +82-2-2228-2100

Citation Format: Yoon KH, Park HS, Kim JH, Kim JY, Lim SM, Kim SI, Cho YU. A prospective randomized study comparing surgery using electrosurgical bipolar sealing devices and surgery using conventional electro-cautery [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr OT2-01-03.

Abstract P6-11-13: Not presented

This abstract was not presented at the symposium.

Complete mitochondrial genome of Siberian musk deer Moschus moschiferus (Artiodactyla: Moschidae) and phylogenetic relationship with other moschus species

The Siberian musk deer, Moschus moschiferus, is an Endangered species in South Korea due to its decreasing population size caused by illegal hunting and habitat destruction. In this study, the complete mitochondrial genome of M. moschiferus was determined using next-generation sequencing. Total length of its mitogenome is 16,356 bp in length, encoding 13 protein-coding genes, 22 transfer RNA genes, two ribosomal RNA genes, and one control region. Its AT contents are 62.4%, which are higher than its GC contents (37.7%) (A, 34.1%; C, 24.9%; G, 12.8%; and T, 28.3%). Phylogenetic relationship of genus Moschus showed topologies similar to those reported in previous studies. Sequence comparison between two M. moschiferus from South Korea indicated high sequence variations with 122 nucleotide differences. These results provide useful information necessary for further phylogenetic studies of Moschus species.

Novel chimeric parapoxvirus CF189 as an oncolytic immunotherapy in triple-negative breast cancer

BACKGROUND

Triple-negative breast cancer is an aggressive subtype of breast cancer with high recurrence rate and poor prognosis. Here we describe a novel, genetically engineered parapoxvirus that efficiently kills triple-negative breast cancer.

METHODS

A novel chimeric parapoxvirus (CF189) was generated via homologous recombination and identified through high-throughput screening. Cytotoxicity was assayed in vitro in 4 triple-negative breast cancer cell lines. Viral replication was examined through standard plaque assay. Orthotopic triple-negative breast cancer xenografts were generated by MDA-MB-468 implantation into the 2nd and 4th mammary fat pads of athymic nude mice and treated with the virus.

RESULTS

Chimeric parapoxvirus (CF189) demonstrated dose-dependent cytotoxicity at low multiplicity of infection, with > 80% cell death 6 days after treatment. Significant reductions in tumor size were observed 2 weeks after intratumoral injection at doses as low as 10³ plaque-forming units (PFU) compared with control (P < 0.01). In addition, abscopal effect (shrinkage of noninjected remote tumors) was clearly demonstrated.

CONCLUSION

Chimeric parapoxvirus (CF189) demonstrated efficient cytotoxicity in vitro and potent antitumor effect in vivo at doses as low as 10³ PFU. These are data encouraging of clinical development for this highly potent agent against triple-negative breast cancer.

Impact of the Ratio of Visceral to Subcutaneous Adipose Tissue in Donor Nephrectomy Patients

OBJECTIVE

It was reported that a metabolic syndrome affected the remaining renal function after living donor nephrectomy. However, the measurement of waist circumference is unclear because it cannot distinguish between visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT). We investigate the clinical correlation between body adipose tissue and renal function recovery after living donor nephrectomy.

METHODS

From July 2013 to February 2015, 75 living kidney donors were enrolled. The VAT and SAT were measured by preoperative computed tomography (CT) scan. Body mass index (BMI), VAT, SAT, and VAT-to-SAT ratio were analyzed according to a postoperative renal function recovery. Receiver operating characteristic (ROC) was performed to predict estimated glomerular filtration rate (eGFR) less than 60 mL/min/1.73 m² at postoperative 6 months for BMI, VAT, SAT, and VAT-to-SAT ratio.

RESULTS

The lowest value of eGFR (57.52 ± 11.20 mL/min/1.73 m²) was measured at postoperative day 7. There was no statistically significant difference in eGFR between 1 month and 3 months. BMI, VAT, SAT, and VAT-to-SAT ratio showed a statistically significant correlation with each other (Pearson correlation, P < .05). Also, the recovery time of eGFR was correlated with VAT-to-SAT ratio; it was significant at postoperative 1, 3, and 6 months. VAT-to-SAT ratio (0.654, 95% confidence interval 0.525-0.783, P = .024) had higher predictive value in ROC.

CONCLUSION

We developed a new variable to predict the value of lower eGFR (less than 60 mL/min/1.73 m²) at a postoperative 6 months in living kidney donor. According to a CT scan, VAT-to-SAT ratio can predict renal function recovery.

Abstract P5-16-25: Serum 25-hydroxyvitamin D levels and oncologic outcomes of breast cancer patients receiving neoadjuvant chemotherapy

Background:According to prior studies, the role of serum vitamin D3 has been inconsistentand clinical implications of 25-hyrdoxyvitamin D (25-OHD) have been little studiedin breast cancer patients receiving neoadjuvant chemotherapy (NCT).

Objectives: The aims of study were to investigate changes in 25-OHD levels before and after NCT and to determine the association of 25-OHD and oncologic outcomes including pathological complete response (pCR) in breast cancer patients.

Patients and Materials: From January 2010 to December 2013, serum 25-OHD levels at pre- and post-NCT were measured in 377 breast cancer patients. The association of serum 25-OHD levels with clinicopathological data including breast cancer subtypes, pCR and survival were retrospectively analysed. Delta 25-OHD was calculated as serum 25-OHDlevels before minus after NCT.

Results: Mean ageof study population was 48.7 yearsand mean follow-up periods were 35.9months.Mean baseline serum 25-OHD concentration was 14.60 ng/mL (standard deviation, 7.44) and more than 80% of patients showed insufficient 25-OHD levels. The mean 25-OHDat post-NCT was 12.16 ng/mL (standard deviation, 6.87).There was a significant decrease in serum 25-OHD after NACT (p&lt;0.001).The pCR rates were 25.7% among study cohort.However, 25-OHD levels at baseline and post-NCT were not related to pCR and survival outcomes. No associations were found between pCR and delta 25-OHD. According to stratification by breast cancer subtypes, however, patients with ≥ -2.67 (median value) of delta 25-OHD revealed a trend of higher achievement of pCR and better survival in luminal A subtype. No associations were found among the other subtypes.

Conclusions: Many Korean breast cancer patients showed insufficient serum 25-OHD levels at diagnosis of malignancy and a significant decrease in serum vitamin D3 after NACT was observed.No significant association of 25-OHD 3 with pCR and survival was found. Therefore, correction or maintenance of appropriate serum 25-OHD levels should be focused for bone health as comprehensive management of breast cancer during NCT.In addition, possible oncological aspects of 25-OHD should further researched individually considering breast subtypes.

Citation Format: Park S, Lee JS, Kim JH, Lim SM, Park HS, Kim SI. Serum 25-hydroxyvitamin D levels and oncologic outcomes of breast cancer patients receiving neoadjuvant chemotherapy [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P5-16-25.

Abstract OT2-04-01: Study on the usefulness of the skin wound therapeutic agent 'Neo dermal activator' in breast cancer surgery

Background : Wound infection after breast cancer surgery is considered to be factors that increase the discomfort of the patient and increase of the extension and the use of antibiotics in the treatment time period, in particular breast cancer postoperative wound infection resulting slow the implementation of adjunctive therapy such as radiation therapy or chemotherapy after surgery can cause, it is important to effectively prevent, there has been a development of a variety of skin wound therapeutic agent to reduce them. The purpose of this study was to evaluate the effects of the wound dressing with existing wound dressing Neo dermal activator compared to the patients receiving preoperative chemotherapy.

Methods : A total of 54 breast cancer patients who recieved BCS & mastectomy devided two group(each 27 patients) through the random assignment between Jan, 2016 and June, 2016. Day one weeks after surgery to examine the wound infection rate (surgical site infection, SSI rate). After six months of outpatient surgery visits to check the wounds of patients, using the VAS records the scar of the wound satisfaction. For patients who underwent radiation therapy, check out the time it took to begin radiation therapy after surgery.

All tests were two-sided. All statistical analyses were performed using SPSS version 20.0 (SPSS Inc., Chicago, Illinois, USA).

Eligbility criteria is :

- one side breast cancer

- not inflammatory breast cancer

- recieved BCS and mastectomy only (without immediate reconstruction surgery)

- stage IV breast cancer.

Citation Format: Kim JH, Lim SM, Kim SI, Park SH, Park HS, Kim JY. Study on the usefulness of the skin wound therapeutic agent 'Neo dermal activator' in breast cancer surgery [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr OT2-04-01.

Ten-Year Experience With Bowel Transplantation at Seoul St. Mary's Hospital

A retrospective review of intestinal transplantation (ITx) at Seoul St. Mary's Hospital was made by collecting clinical data over the past 10 years. Fifteen consecutive cases from 2004 were analyzed. Five children and 10 adults (6 months to 69 years of age) were included. Primary diseases in adults included 4 mesenteric vessel thromboses, 2 strangulations, and 1 each of visceral myopathy, malignant gastrointestinal stromal tumor (GIST), mesenteric lymphangiectasis, and injury. Pediatric cases involved 2 Hirschsprung disease, 2 visceral myopathy, and 1 necrotizing enterocolitis. Three of 7 stomas were closed using a serial transverse enteroplasty procedure before transplantation. The ITx were performed using 3 living-donor Itx, 12 deceased-donor ITx, 14 isolated Itx, and 1 modified multivisceral transplantation. Daclizumab, basiliximab, alemtusumab, or basiliximab with rabbit antithymocyte globulin (rATG) was used for the induction; tacrolimus monotherapy was used as the basic maintenance immunosuppressant; and m-TOR inhibitor was used for renal dysfunction patients. Seven cases of acute cellular rejection were treated with rATG. Three cases of antibody-mediated rejection were treated with rituximab alone or with rituximab and bortezomib combination. There were 4 cases of early mortality within 6 months after Itx. Causes of death were declamping shock, cardiac tamponade with acute cellular rejection, dysmotility, and sepsis. Surgical complications consisted of 1 feeding jejunostomy displacement, and a minor leakage at a colo-colostomy site. One-year survival of the patient and graft was 73.33% (Kaplan-Meier survival curve). Although the total number of ITx is small, its social impact has been remarkable in changing the related laws and reimbursement policy in Korea.