Oncolytic herpes viral therapy is effective in the treatment of hepatocellular carcinoma cell lines

Hepatic Manifestations of Nonhepatotropic Infectious Agents Including Severe Acute Respiratory Syndrome Coronavirus-2, Adenovirus, Herpes Simplex Virus, and Coxiella burnetii

Nonhepatotropic viruses such as adenovirus, herpes simplex virus, flaviviruses, filoviruses, and human herpes virus, and bacteria such as Coxiella burnetii, can cause liver injury mimicking acute hepatitis. Most of these organisms cause a self-limited infection. However, in immunocompromised patients, they can cause severe hepatitis or in some cases fulminant hepatic failure requiring an urgent liver transplant. Hepatic dysfunction is also commonly seen in patients with severe acute respiratory syndrome coronavirus-2 infection. Patients with preexisting liver diseases are likely at risk for severe coronavirus disease 2019 (COVID-19) and may be associated with poor outcomes.

Neoadjuvant Use of Oncolytic Herpes Virus G47Δ Enhances the Antitumor Efficacy of Radiofrequency Ablation

G47Δ is a triple-mutated oncolytic herpes simplex virus type 1 designed to induce antitumor immune responses efficiently. We examine the usefulness of G47Δ as a neoadjuvant therapy for radiofrequency ablation (RFA), a standard local treatment for certain cancers such as liver cancer, but remote recurrences within the same organ often occur. In A/J mice harboring bilateral subcutaneous Neuro2a tumors, the left tumors were treated with G47Δ intratumoral injections followed by RFA. Whereas the RFA-treated tumors were all eradicated, the growth of the right tumors was evaluated and tumor-infiltrating lymphocytes were analyzed. The G47Δ+RFA treatment caused smaller volumes of right tumors, accompanied by increased CD8⁺/CD45⁺ T cells, compared with G47Δ monotherapy. After depletion of CD8⁺ T cells, the enhanced efficacy on the contralateral tumors was completely abolished. Neoadjuvant G47Δ led to rejection of rechallenged tumors, which was caused by efficient induction of specific antitumor immune responses shown by enzyme-linked immunospot (ELISPOT) assays. Treatment of tumor-harboring animals with an anti-programmed cell death 1 ligand 1 (PD-L1) antibody led to even greater efficacy on contralateral tumors. Our study indicates that the neoadjuvant use of G47Δ effectively enhances the efficacy of RFA via CD8⁺ T cell-dependent immunity that is further augmented by an immune checkpoint inhibitor.

Orthotopic hepatocellular carcinoma: molecular imaging-monitored intratumoral hyperthermia-enhanced direct oncolytic virotherapy

Objective:

To validate the feasibility of molecular imaging-monitored intratumoral radiofrequency hyperthermia (RFH) enhanced direct oncolytic virotherapy for hepatocellular carcinoma (HCC).

Methods:

This study included in vitro experiments using luciferase-labeled rat HCC cells and in vivo validation experiments on rat models with orthotopic HCCs. Both cells and HCCs in four groups (n = 6/group) were treated by: (1) combination therapy of oncolytic virotherapy (T-VEC) plus RFH at 42 °C for 30 min; (2) oncolytic virotherapy alone; (3) RFH alone; and (4) saline. For in vitro confirmation, confocal microscopy and bioluminescence optical imaging were used to evaluate the cell viabilities. For in vivo validation, oncolytic viruses were directly infused into rat HCCs through a multi-functional perfusion-thermal RF electrode, followed by RFH. Ultrasound and optical imaging were used to follow up size and bioluminescence signal changes of tumors overtime, which were correlated with subsequent laboratory examinations.

Results:

For in vitro experiments, confocal microscopy showed the lowest number of viable cells, as well as a significant decrease of bioluminescence signal intensity of cells with combination therapy group, compared to other three groups (p < .001). For in vivo experiments, ultrasound and optical imaging showed the smallest tumor volume, and significantly decreased bioluminescence signal intensity in combination therapy group compared to other three groups (p < .05), which were well correlated with pathologic analysis.

Conclusion:

It is feasible of using molecular imaging to guide RFH-enhanced intratumoral oncolytic virotherapy of HCC, which may open new avenues to prevent residual or recurrent disease of thermally ablated intermediate-to-large HCCs.

Potent efficacy signals from systemically administered oncolytic herpes simplex virus (HSV1716) in hepatocellular carcinoma xenograft models

Oncolytic herpes simplex virus (HSV1716), lacking the neurovirulence factor ICP34.5, has highly selective replication competence for cancer cells and has been used in clinical studies of glioma, melanoma, head and neck squamous cell carcinoma, pediatric non-central nervous system solid tumors, and malignant pleural mesothelioma. To date, 88 patients have received HSV1716 and the virus is well tolerated, with selective replication in tumor cells and no spread to surrounding normal tissue. We assessed the potential value of HSV1716 in preclinical studies with two human hepatocellular carcinoma cell lines, HuH7 and HepG2-luc. HSV1716 displayed excellent replication kinetics in vitro in HepG2-luc cells, a cell line engineered to express luciferase, and virus-mediated cell killing correlated with loss of light emissions from the cells. In vivo, the HepG2-luc cells readily formed light-emitting xenografts that were easily visualized by an in vivo imaging system and efficiently eliminated by HSV1716 oncolysis after intratumoral injection. HSV1716 also demonstrated strong efficacy signals in subcutaneous HuH7 xenografts in nude mice after intravenous administration of virus. In the HuH7 model, the intravenously injected virus replicated prolifically immediately after efficient tumor localization, resulting in highly significant reductions in tumor growth and enhanced survival. Our preclinical results demonstrate excellent tumor uptake of HSV1716, with prolific replication and potent oncolysis. These observations warrant a clinical study of HSV1716 in hepatocellular carcinoma.

Preclinical evaluation of transcriptional targeting strategy for human hepatocellular carcinoma in an orthotopic xenograft mouse model

Gene regulation of many key cell-cycle players in S-, G(2) phase, and mitosis results from transcriptional repression in their respective promoter regions during the G(0) and G(1) phases of cell cycle. Within these promoter regions are phylogenetically conserved sequences known as the cell-cycle-dependent element (CDE) and cell-cycle genes homology regions (CHR) sites. Thus, we hypothesize that transcriptional regulation of cell-cycle regulation via the CDE/CHR region together with liver-specific apolipoprotein E (apoE)-hAAT promoter could bring about a selective transgene expression in proliferating human hepatocellular carcinoma. We show that the newly generated vector AH-6CC-L2C could mediate hepatocyte-targeted luciferase gene expression in tumor cells and freshly isolated short-term hepatocellular carcinoma cultures from patient biopsy. In contrast, normal murine and human hepatocytes infected with AH-6CC-L2C expressed minimal or low luciferase activities. In the presence of prodrug 5-fluorocytosine (5-FC), AH-6CC-L2C effectively suppressed the growth of orthotopic hepatocellular carcinoma patient-derived xenograft mouse model via the expression of yeast cytosine deaminase (yCD) that converts 5-FC to anticancer metabolite 5-fluoruracil. More importantly, we show that combination treatment of AH-6CC-L2C with an EZH2 inhibitor, DZNep, that targets EpCAM-positive hepatocellular carcinoma, can bring about a greater therapeutic efficacy compared with a single treatment of virus or inhibitor. Our study showed that targeting proliferating human hepatocellular carcinoma cells through the transcriptional control of therapeutic gene could represent a feasible approach against hepatocellular carcinoma.

Phase I/II study of oncolytic herpes simplex virus NV1020 in patients with extensively pretreated refractory colorectal cancer metastatic to the liver

This multicenter phase I/II study evaluated the safety, pharmacokinetics, and antitumor effects of repeated doses of NV1020, a genetically engineered oncolytic herpes simplex virus, in patients with advanced metastatic colorectal cancer (mCRC). Patients with liver-dominant mCRC received four fixed NV1020 doses via weekly hepatic artery infusion, followed by two or more cycles of conventional chemotherapy. Phase I included cohorts receiving 3 × 10(6), 1 × 10(7), 3 × 10(7), and 1 × 10(8) plaque-forming units (PFU)/dose to determine the optimal biological dose (OBD) for phase II. Blind independent computed tomography scan review was based on RECIST (response evaluation criteria in solid tumors) to assess hepatic tumor response. Phase I and II enrolled 13 and 19 patients, respectively. Patients experienced transient mild-moderate febrile reactions after each NV1020 infusion. Grade 3/4 virus-related toxicity was limited to transient lymphopenia in two patients. NV1020 shedding was not detected. Simultaneous cytokine and grade 1 coagulation perturbations were dose-limiting at 1 × 10(8) PFU/dose, considered the OBD. All 22 OBD patients had previously received 5-fluorouracil; most had received oxaliplatin or irinotecan (50% had both), many with at least one targeted agent. After NV1020 administration, 50% showed stable disease. The best overall tumor control rate after chemotherapy was 68% (1 partial response, 14 stable disease); this did not correlate with baseline variables or chemotherapy. Median time to progression was 6.4 months (95% confidence interval: 2, 8.9); median overall survival was 11.8 months (95% confidence interval: 8.3, 20.7). One-year survival was 47.2%. We conclude that NV1020 stabilizes liver metastases with minimal toxicity in mCRC. It may resensitize metastases to salvage chemotherapy and extend overall survival. A randomized phase II/III trial now appears justified.

A third-generation herpesvirus is effective against gastroesophageal cancer

BACKGROUND

Gastroesophageal cancer remains a leading cause of cancer deaths and is uniformly fatal in patients presenting with metastases and recurrence. This study sets out to determine the effect of a third-generation, replication-competent, oncolytic herpes simplex type 1 virus containing transgenes encoding for a fusogenic membrane glycoprotein and Fcy::Fur, against gastroesophageal cancer.

METHODS

The cytotoxic effect of the virus was tested on human gastroesophageal cancer cell lines OCUM-2MD3, MKN-45, AGS, MKN-1, MKN-74, and BE-3 at sequential multiplicities of infection (MOI). Cytotoxicity was measured using a lactate dehydrogenase assay. Viral replication was tested by serially diluting supernatants from viral infections and titering on VERO cells via standard plaque assay. Correlations of cytotoxicity and viral replication were also investigated.

RESULTS

All cell lines were susceptible to viral infection and demonstrated a dose-dependent effect, with greater and faster cytotoxicity at higher MOIs. Viral replication was supported in the cell lines tested, with peak titers by d 5, some supporting as high as >40,000× amplification. Cell lines with longer doubling times (>30 h) also achieved higher viral titers at a MOI of 0.1. Cell lines with shorter doubling times achieved 50% cell kill in fewer days, with an average of 2.3 d for cell lines with doubling times under 30 h compared with 4.4 d for cell lines with doubling times over 30 h.

CONCLUSION

These results suggest that this third-generation oncolytic herpesvirus can effectively infect and lyse gastroesophageal cancer cells and may provide a novel therapy against gastroesophageal cancer.

Impact of immunosuppressive treatment on endothelial biomarkers after kidney transplantation

Endothelial dysfunction occurs in hemodialysis and kidney-transplanted patients and can be enhanced by immunosuppressive therapy. Circulating endothelial cells (CEC), endothelial microparticles (EMP) and sVCAM-1 provide information on endothelium activation and damage. We compared the impact of two immunosuppressive regimens (CsA/Aza vs. Tac/MMF) on the kinetics of CEC, EMP and sVCAM-1 levels in 52 patients, both before graft and 3, 6, 9 and 12 months after graft, in reference to 50 healthy controls. CEC, EMP and sVCAM-1 levels were significantly decreased 1 year after transplantation (M12) as compared to pretransplant values. At M12, CEC and sVCAM-1 levels were significantly higher than those of controls whereas EMP reached normal values. Nine months postgraft, lower CEC and normalized EMP levels were found in patients receiving cyclosporine microemulsion/ azathioprine (CsA/Aza) when compared to patients treated with tacrolimus/ mycophenolate mofetil (Tac/MMF). Multivariate analysis evidenced positive correlations between CEC and history of cardiovascular diseases and between EMP and cytomegalovirus infection at M12. In conclusion, our combined analysis of endothelial injury markers confirms the favorable impact of renal transplantation on endothelium, and show that CEC levels discriminate treatment-associated endothelial toxicity. These results enlighten the potential of these noninvasive blood biomarkers in indexing vascular injury and optimize therapeutic options.

Herpes simplex virus NV1020 as a novel and promising therapy for hepatic malignancy

BACKGROUND

Patients with hepatic malignancy have a dismal prognosis with standard therapies. NV1020 is an oncolytic herpes simplex virus that has potential to be a safe and effective therapeutic agent for this disease.

OBJECTIVE

We set out to discuss the development of NV1020 as an oncolytic agent and explore the potential role of this particular virus in the setting of human hepatic cancer.

METHODS

The scope of this review includes an overview of preclinical experience with NV1020, as well as an examination of current standard and developing therapies for liver cancer. The primary focus, however, is on the safety and potential clinical efficacy of NV1020 against hepatic malignancy.

RESULTS/CONCLUSION

We have found that NV1020 is a safe, novel therapeutic agent for treatment of refractory hepatic malignancy.

Advances in experimental and translational research in the treatment of hepatocellular carcinoma

Hepatocellular cancer (HCC) is the fifth-leading cause of cancer and the third-leading cause of cancer related deaths world-wide. Current treatment options are limited, as HCC has been shown to be a highly resistant type of cancer to most current treatment modalities. Novel approaches are being explored in the fields of gene therapy, viral oncolytics, radioembolization, and several new biologic therapies. This article summarizes these recent clinical findings and discusses what role they will have in the future treatment of HCC.

Recent clinical progress in virus-based therapies for cancer

As our knowledge of the molecular basis of cancer expands, viral vectors have been increasingly studied as potential antitumour therapeutic agents. With their ability to invade and replicate within target cells, viruses have been utilised as oncolytic agents to directly lyse tumour cells. Viruses can also deliver their genetic payload into infected cells, allowing for the repair of defective tumour suppressor genes, disruption of oncogenic pathways, and production of cytokines that activate the immune system. Finally, viruses encoding tumour-associated antigens can infect dendritic cells, triggering the development of a tumour-specific immune response. The ability to engineer viruses with high levels of tumour specificity and efficient rates of infection has enhanced the safety profile of these agents, allowing for the development of viable therapeutic options that have been examined in the clinic, either alone or in conjunction with more conventional therapies. This review highlights the principles underlying virus-based therapies for cancer, with an emphasis on recent developments from the clinic.

Gene therapy of liver cancer

The application of gene transfer technologies to the treatment of cancer has led to the development of new experimental approaches like gene directed enzyme/pro-drug therapy (GDEPT), inhibition of oncogenes and restoration of tumor-suppressor genes. In addition, gene therapy has a big impact on other fields like cancer immunotherapy, anti-angiogenic therapy and virotherapy. These strategies are being evaluated for the treatment of primary and metastatic liver cancer and some of them have reached clinical phases. We present a review on the basis and the actual status of gene therapy approaches applied to liver cancer.