STING activator 2'3'-cGAMP enhanced HSV-1-based oncolytic viral therapy.

Oncolytic viruses (OVs) can selectively replicate in tumor cells and remodel the microenvironment of immunologically cold tumors, making them a promising strategy to evoke antitumor immunity. Similarly, agonists of the stimulator of interferon genes (STING)-interferon (IFN) pathway, the main cellular antiviral system, provide antitumor benefits by inducing the activation of dendritic cells (DC). Considering how the activation of the STING-IFN pathway could potentially inhibit OV replication, the use of STING agonists alongside OV therapy remains largely unexplored. Here, we explored the antitumor efficacy of combining an HSV-1-based OV, C-REV, with a membrane-impermeable STING agonist, 2'3'-GAMP. Our results demonstrated that tumor cells harbor a largely defective STING-IFN pathway, thereby preventing significant antiviral IFN induction regardless of the permeability of the STING agonist. In vivo, the combination therapy induced more proliferative KLRG1-high PD1-low CD8+ T-cells and activated CD103+ DC in the tumor site and increased tumor-specific CD44+ CD8+ T-cells in the lymph node. Overall, the combination therapy of C-REV with 2'3'-cGAMP elicited antitumor immune memory responses and significantly enhanced systemic antitumor immunity in both treated and non-treated distal tumors.

S-1 facilitates canerpaturev (C-REV)-induced antitumor efficacy in a triple-negative breast cancer model.

Canerpaturev (C-REV) is a highly attenuated, replication-competent, mutant strain of oncolytic herpes simplex virus type 1 that may be an effective new cancer treatment option. S-1, an oral formulation containing the 5-fluorouracil (5-FU) prodrug tegafur and the two enzyme modulators gimeracil and oteracil, is used as a key chemotherapeutic agent for metastatic recurrent breast cancer. Although the antitumor effects of oncolytic viruses combined with 5-FU in vivo have been reported, the detailed mechanisms are unknown. Here, we investigated the antitumor mechanism of the combination of C-REV and S-1 in triple-negative breast cancer (TNBC) in the context of tumor immunity. The combined effect of C-REV and S-1 was evaluated in a bilateral tumor model of murine TNBC 4T1 in vivo. S-1 enhanced the TNBC growth inhibitory effects of C-REV, and decreased the number of tumor-infiltrating, myeloid-derived suppressor cells (MDSCs), which suppress both innate and adaptive immune responses. Moreover, C-REV alone and in combination with S-1 significantly increased the number of CD8+ T cells in the tumor and the production of interferon γ (IFNγ) from these cells. Our findings indicate that C-REV suppresses TNBC tumor growth by inducing the expansion of effector CD8+ T cell subsets in tumors in which S-1 can inhibit MDSC function. Our study suggests that MDSCs may be an important cellular target for breast cancer treatment. The combination of C-REV and S-1 is a new approach that might be directly translated into future clinical trials against TNBC.

C-REV Retains High Infectivity Regardless of the Expression Levels of cGAS and STING in Cultured Pancreatic Cancer Cells.

Oncolytic virus (OV) therapy is widely considered as a major breakthrough in anti-cancer treatments. In our previous study, the efficacy and safety of using C-REV for anti-cancer therapy in patients during stage I clinical trial was reported. The stimulator of interferon genes (STING)-TBK1-IRF3-IFN pathway is known to act as the central cellular host defense against viral infection. Recent reports have linked low expression levels of cGAS and STING in cancer cells to poor prognosis among patients. Moreover, downregulation of cGAS and STING has been linked to higher susceptibility to OV infection among several cancer cell lines. In this paper, we show that there is little correlation between levels of cGAS/STING expression and susceptibility to C-REV among human pancreatic cancer cell lines. Despite having a responsive STING pathway, BxPC-3 cells are highly susceptible to C-REV infection. Upon pre-activation of the STING pathway, BxPc-3 cells exhibited resistance to C-REV infection. However, without pre-activation, C-REV completely suppressed the STING pathway in BxPC-3 cells. Additionally, despite harboring defects in the STING pathway, other high-grade cancer cell lines, such as Capan-2, PANC-1 and MiaPaCa-2, still exhibited low susceptibility to C-REV infection. Furthermore, overexpression of STING in MiaPaCa-2 cells altered susceptibility to a limited extent. Taken together, our data suggest that the cGAS-STING pathway plays a minor role in the susceptibility of pancreatic cancer cell lines to C-REV infection.

Oncolytic herpes simplex virus HF10 (canerpaturev) promotes accumulation of CD8+ PD-1- tumor-infiltrating T cells in PD-L1-enriched tumor microenvironment.

Oncolytic viruses (OVs) remodel the tumor microenvironment by switching a "cold" tumor into a "hot" tumor with high CD8+ T-cell infiltration. CD8+ T-cell activity plays an essential role in the antitumor efficacy of OVs. However, the activity of T cells is impaired by the programmed cell death protein-1/programmed cell death-ligand 1 (PD-1/PD-L1) interaction. To date, it remains unclear why OVs alone have a significant antitumor activity even when PD-L1 expression persists on tumor or immune cells. In this study, we found that canerpaturev (C-REV) treatment significantly suppressed tumor growth, even though it induced a significant increase in PD-L1 expression in tumors in vivo as well as persistence of high PD-L1 expression on antigen-presenting cells (macrophage and dendritic cells [DCs]). Surprisingly, we observed that C-REV treatment increased the abundance of activated CD8+ PD-1- tumor-infiltrating lymphocytes (TILs) in the tumor on both the injected and contralateral sides, although infiltration of CD8+ PD-1high TILs into the tumor was observed in the control group. Moreover, the difference in PD-1 expression was observed only in tumors after treatment with C-REV, whereas most CD8+ T cells in the spleen, tumor-draining lymph nodes and blood were PD-1-negative, and this did not change after C-REV treatment. In addition, changes in expression of T-cell immunoglobulin and mucin-domain containing-3 and T-cell immune-receptor with Ig and ITIM domains were not observed on CD8+ TILs after C-REV treatment. Taken together, our findings may reveal mechanisms that allow OVs to trigger an antitumor immune response, irrespective of a PD-L1-enriched tumor microenvironment, by recruitment of CD8+ PD-1- TILs.

Characteristics of Lung Metastasis as an Initial Recurrence Pattern After Curative Resection of Pancreatic Cancer.

OBJECTIVES: Understanding the disparity in clinical course because of differences in initial recurrence patterns could lead to a more accurate estimation of prognosis and optimal treatment. METHODS: Patients who underwent resection for pancreatic cancer between January 2003 and December 2016 were identified from a prospective database. We analyzed the association between clinicopathological information or survival outcomes and initial recurrence patterns. RESULTS: The most frequent recurrence pattern was locoregional recurrence (n = 84, 31.3%), followed by simultaneous multiple recurrences (n = 65, 24.2%), liver metastasis (n = 53, 19.8%), peritoneal dissemination (n = 41, 15.3%), and lung metastasis (n = 20, 7.5%). In addition, survival outcomes were significantly longer in the lung metastasis group than in the other recurrence pattern group (recurrence-free survival, 18.2 vs 8.2 months, P < 0.001; overall survival, 86.4 vs 21.0 months, P < 0.001; and survival after recurrence, 37.1 vs 9.3 months, P < 0.001). The lung metastasis group had a significantly higher proportion of pancreatic body and tail cancer (P < 0.002) and arterial invasion (P = 0.006) than the other recurrence pattern group. CONCLUSIONS: Lung metastasis as an initial recurrence pattern frequently occurred in patients with body and tail cancer and patients with arterial invasion.

Novel Prognostic Implications of DUPAN-2 in the Era of Initial Systemic Therapy for Pancreatic Cancer.

BACKGROUND: This study aimed to explore the impact of serum tumor markers on survival for patients with pancreatic cancer (PC) who received initial systemic therapy (IST) followed by surgery. METHODS: Between April 2010 and July 2018, 285 consecutive patients who underwent curative intent surgery for PC were enrolled in the study. The relation between carbohydrate antigen 19-9 and duke pancreatic monoclonal antigen type 2 (DUPAN-2) after IST was analyzed as well as PC prognosis. RESULTS: The study identified 95 patients who underwent systemic chemotherapy with or without radiotherapy as IST from the our prospectively maintained database at the Department of Gastroenterological Surgery (Surgery II), Nagoya University Graduate School of Medicine, Nagoya, Japan. Survival analysis of the 95 patients showed significant differences in recurrence-free survival (RFS) and overall survival (OS) between the DUPAN-2-normalized (D-normalized) and DUPAN-2-unnormalized (D-unnormalized) groups (median RFS, 24.1 vs. 14.2 months, p = 0.003; median OS, not reached vs. 29.6 months, p = 0.003). In addition, a tendency of differences in survival was observed between the D-normalized and D-unnormalized groups with borderline resectable PC (RFS, 20.1 vs. 14.2 months, p = 0.052; OS, not reached vs. 29.6 months, p = 0.081), and significant differences in survival were observed between the D-normalized and D-unnormalized groups with unresectable PC (RFS, 25.1 vs. 12.1 months, p < 0.001; OS, not reached vs. 11.4 months, p < 0.001). Furthermore, multivariate analysis demonstrated that normalized DUPAN-2 independently predicted survival of resected PC [RFS: hazard ratio (HR) 2.180; 95% confidence interval (CI) 1.16-4.08, p = 0.015; OS: HR 2.806; 95% CI 1.19-6.62, p = 0.018]. CONCLUSIONS: During IST, DUPAN-2 normalization may potentially predict prolonged survival for PC patients and optimal timing for conversion surgery in IST.

Comparison of non-invasive liver reserve and fibrosis models: Implications for surgery and prognosis for hepatocellular carcinoma.

AIM: This study aimed to assess the clinical utility of preoperative evaluation of liver fibrosis using platelet-albumin-bilirubin (PALBI) grade, Fibrosis-4 index (FIB-4), and aspartate transaminase-to-platelet ratio index (APRI) for hepatocellular carcinoma (HCC) patients and explore the clinical impact of these models with regard to perioperative risks and HCC prognosis. METHODS: Between January 2003 and December 2018, 305 consecutive patients who underwent hepatectomy for HCC were enrolled. RESULTS: The APRI showed the most robust diagnostic performance through each fibrosis stage among three models (PALBI, FIB-4, and APRI): fibrosis stage 3 (f3), area under the curve [AUC] = 0.55, 0.72, and 0.76; and f4, AUC = 0.51, 0.71, and 0.76, respectively). In addition, survival analysis revealed that all three models were significantly associated with HCC prognosis. PALBI (grade 1 vs. 2, 3): recurrence-free survival (RFS): median survival time (MST), 34 vs. 17 months, 0.007; overall survival (OS): MST, 115 vs. 68, 0.02. FIB-4 (grade 1, 2 vs. 3): RFS: MST, 34 vs. 22, 0.004, OS: MST, 120 vs. 63, 0.0001. APRI (grade 1, 2 vs. 3), RFS: MST, 30 vs. 20, 0.0005; OS: MST, 107 vs. 55, 0.0003. Among three scoring systems, only PALBI grade was significantly associated with both operative time (median, 303 vs. 340 min, 0.01) and intraoperative blood loss (median, 581 vs. 859 mL, 0.03). CONCLUSIONS: This study showed robust performances of selected liver reserve and fibrosis models to predict HCC prognosis. Of them, PALBI might be used for assessing perioperative risks for hepatectomy for HCC.

Combination of Cetuximab and Oncolytic Virus Canerpaturev Synergistically Inhibits Human Colorectal Cancer Growth.

The naturally occurring oncolytic herpes simplex virus canerpaturev (C-REV), formerly HF10, proved its therapeutic efficacy and safety in multiple clinical trials against melanoma, pancreatic, breast, and head and neck cancers. Meanwhile, patients with colorectal cancer, which has increased in prevalence in recent decades, continue to have poor prognosis and morbidity. Combination therapy has better response rates than monotherapy. Hence, we investigated the antitumor efficacy of cetuximab, a widely used anti-epidermal growth factor receptor (EGFR) monoclonal antibody, and C-REV, either alone or in combination, in vitro and in an in vivo human colorectal xenograft model. In human colorectal cancer cell lines with different levels of EGFR expression (HT-29, WiDr, and CW2), C-REV exhibited cytotoxic effects in a time- and dose-dependent manner, irrespective of EGFR expression. Moreover, cetuximab had no effect on viral replication in vitro. Combining cetuximab and C-REV induced a synergistic antitumor effect in HT-29 tumor xenograft models by promoting the distribution of C-REV throughout the tumor and suppressing angiogenesis. Application of cetuximab prior to C-REV yielded better tumor regression than administration of the drug after the virus. Thus, cetuximab represents an ideal virus-associated agent for antitumor therapy, and combination therapy represents a promising antitumor strategy for human colorectal cancer.

Prognostic Impact of Portal System Invasion in Pancreatic Cancer Based on Image Classification.

OBJECTIVES: This study aimed to clarify the correlation between image classification and the pathological degree of portal system invasion (PSI) and to evaluate the prognostic impact of PSI in pancreatic cancer (PC). METHODS: Pancreatic cancer patients with surgical resections (head, n = 244; body and tail, n = 80) were enrolled in this study. RESULTS: Based on imaging findings, portal vein (PV) invasion was classified as type A (absent), B (unilateral narrowing), C (bilateral narrowing), or D (stenosis or obstruction with collaterals). Splenic vein (SPV) invasion was classified as type α (absent), ß (stenosis), or γ (obstruction). The pathological grade of venous invasion was classified as grade 0 (no invasion), 1 (tunica adventitia), 2 (tunica media), or 3 (tunica intima). In PV and SPV invasions, image classification and pathological grade showed significant correlation (PV: ρ = 0.696; SPV: ρ = 0.681). Patients with PV invasion deeper than type B exhibited significantly poorer survival than type A (P < 0.0001). In contrast, there was no difference in survival among types α, ß, and γ. CONCLUSIONS: Image classification was correlated with the pathological grade of PSI in PC. Although not applicable for SPV invasion, image classification of PV invasion is a robust indicator for PC prognosis.

The Current Status and Future Prospects of Oncolytic Viruses in Clinical Trials against Melanoma, Glioma, Pancreatic, and Breast Cancers.

Oncolytic viral therapy has been accepted as a standard immunotherapy since talimogene laherparepvec (T-VEC, Imlygic®) was approved by the Food and Drug Administration (FDA) and European Medicines Agency (EMA) for melanoma treatment in 2015. Various oncolytic viruses (OVs), such as HF10 (Canerpaturev-C-REV) and CVA21 (CAVATAK), are now actively being developed in phase II as monotherapies, or in combination with immune checkpoint inhibitors against melanoma. Moreover, in glioma, several OVs have clearly demonstrated both safety and a promising efficacy in the phase I clinical trials. Additionally, the safety of several OVs, such as pelareorep (Reolysin®), proved their safety and efficacy in combination with paclitaxel in breast cancer patients, but the outcomes of OVs as monotherapy against breast cancer have not provided a clear therapeutic strategy for OVs. The clinical trials of OVs against pancreatic cancer have not yet demonstrated efficacy as either monotherapy or as part of combination therapy. However, there are several oncolytic viruses that have successfully proved their efficacy in different preclinical models. In this review, we mainly focused on the oncolytic viruses that transitioned into clinical trials against melanoma, glioma, pancreatic, and breast cancers. Hence, we described the current status and future prospects of OVs clinical trials against melanoma, glioma, pancreatic, and breast cancers.

[Effective chemotherapy with bevacizumab/FOLFOX4 for neuroendocrine carcinoma of the ascending colon - a case study].

A 63-year-old woman underwent surgery for Stage IV cancer of the ascending colon with multiple lymph node metastases. The pathological diagnosis was neuroendocrine carcinoma. Following first-line chemotherapy, the patient presented clinically with progressive disease (PD). Second-line chemotherapy with bevacizumab/Leucovorin and 5-fluorouracil with oxaliplatin (FOLFOX4) was effective and a partial response (PR) was achieved after 7 courses of therapy, as determined by computed tomography (CT) examination. Neuroendocrine carcinoma is known to be extremely malignant; however, this case suggests that chemotherapy with bevacizumab may improve the prognosis of this disease.