Oncolytic Measles Vaccine Virus Research Articles

In Vitro Sensitivity of Neuroendocrine Neoplasms to an Armed Oncolytic Measles Vaccine Virus

Neuroendocrine neoplasms represent a heterogenous group of rare tumors whose current therapeutic options show only limited efficacy. Oncolytic viruses exert their mode of action through (onco-)lysis of infected tumor cells and the induction of a systemic antitumoral immune response in a virus-induced inflammatory micromilieu. Here, we investigated the potential of our well-established second-generation suicide-gene armed oncolytic measles vaccine virus (MeV-SCD) in five human NEN cell lines. First, (i) expression of the MeV receptor CD46 and (ii) its correlation with primary infection rates were analyzed. Next, (iii) promising combination partners for MeV-SCD were tested by employing either the prodrug 5-fluorocytosine, which is converted into the chemotherapeutic compound 5-fluorouracil, or the mTOR-inhibitor everolimus. As a result, MeV-SCD was found to kill all NEN tumor cell lines efficiently in a dose-dependent manner. This oncolytic effect was further enhanced by exploiting the prodrug-converting system, which was found to be highly instrumental in overcoming the partial resistance found in a single NEN cell line. Furthermore, viral replication was unaffected by everolimus, which is a basic requirement for combined use in NEN patients. These data suggest that MeV-SCD has profound potential for patients with NEN, thus paving the way for early clinical trials.

Chemovirotherapy for pancreatic cancer: Gemcitabine plus oncolytic measles vaccine virus.

Oncolytic virotherapy with vaccine viruses employs replicative vectors, which quite selectively infect tumor cells leading to massive virus replication followed by subsequent profound tumor cell death (oncolysis). Measles vaccine virus (MeV) has already shown great oncolytic activity against different types of cancers, including pancreatic cancer. Gemcitabine is a first line chemotherapeutic drug used for pancreatic cancer in palliative treatment plans. Furthermore, this drug can be used to induce senescence, a permanent cell cycle arrest, in tumor cells. In our preclinical work, three well-characterized immortalized human pancreatic cancer cell lines were used to investigate the combinatorial effect of MeV-based virotherapy together with the chemotherapeutic compound gemcitabine. Viability assays revealed that the combination of only small amounts of MeV together with subtherapeutic concentrations of gemcitabine resulted in a tumor cell mass reduction of >50%. To further investigate the replication of the oncolytic MeV vectors under these distinct combinatorial conditions, viral growth curves were generated. As a result, viral replication was found to be only slightly diminished in the presence of gemcitabine. As gemcitabine induces senescence, the effect of MeV on that phenomenon was explored using a senescence-associated β-galactosidase assay. Notably, gemcitabine-induced tumor cell senescence was not impaired by MeV. Accordingly, the chemovirotherapeutic combination of gemcitabine plus oncolytic MeV constitutes a novel therapeutic option for advanced pancreatic carcinoma that is characterized by the mutual improvement of the effectiveness of each therapeutic component.

Novel epi-virotherapeutic treatment of pancreatic cancer combining the oral histone deacetylase inhibitor resminostat with oncolytic measles vaccine virus

Oncolytic viruses (OV) constitute highly promising innovative biological anticancer agents. However, like every other antitumoral compound, OV are also faced with both primary and secondary mechanisms of resistance. To overcome those barriers and moreover amplify the therapeutic potential of OV, we evaluated a novel combined approach composed of the oral histone deacetylase inhibitor resminostat and an oncolytic measles vaccine virus (MeV) for a future epi‑virotherapy of pancreatic ductal adenocarcinoma. Cytotoxicity assays revealed that combined epi-virotherapeutic treatment of four well-characterized human pancreatic cancer cell lines resulted in a beneficial tumor cell killing as compared to either monotherapeutic approach. Notably, epi-virotherapeutic treatment of MIA PaCa-2 and partly also of PANC‑1 pancreatic cancer cells resulted in a tumor cell mass reduction being significantly more pronounced than it would be expected in case of an additive effect only, indicating a synergistic mode of action when combining resminostat with MeV. We further found that the epigenetic compound resminostat neither impaired MeV growth kinetics nor prevented the activation of the interferon signaling pathway which plays an important role in mediating primary and secondary resistances to OV. Moreover, we yielded information that the pharma-codynamic function of resminostat was presumably not altered in the course of pancreatic cancer cell infections with MeV. Taken together, these promising results favor the onset of epi-viro-thera-peutic clinical trials in patients suffering from advanced pancreatic ductal adenocarcinoma.

Combination of the oral histone deacetylase inhibitor resminostat with oncolytic measles vaccine virus as a new option for epi-virotherapeutic treatment of hepatocellular carcinoma (HCC)

Combination of the oral histone deacetylase inhibitor resminostat with oncolytic measles vaccine virus as a new option for epi-virotherapeutic treatment of hepatocellular carcinoma (HCC)

Combination of the oral histone deacetylase inhibitor resminostat with oncolytic measles vaccine virus as a new option for epi-virotherapeutic treatment of hepatocellular carcinoma

Epigenetic therapies such as histone deacetylase inhibitors (HDACi) not only have the capability to decrease tumor cell proliferation and to induce tumor cell death but also to silence antiviral response genes. Here, we investigated whether the combination of an oncolytic measles vaccine virus (MeV) with the novel oral HDACi resminostat (Res), being in clinical testing in patients with hepatocellular carcinoma (HCC), results in an enhanced efficacy of this epi-virotherapeutic approach compared to any of the two corresponding monotherapies. When testing a panel of human hepatoma cell lines, we found (i) a significantly improved rate of primary infections when using oncolytic MeV under concurrent treatment with resminostat, (ii) a boosted cytotoxic effect of the epi-virotherapeutic combination (Res + MeV) with enhanced induction of apoptosis, and, quite importantly, (iii) an absence of any resminostat-induced impairment of MeV replication and spread. Beyond that, we could also show that (iv) resminostat, after hepatoma cell stimulation with exogenous human interferon (IFN)-β, is able to prevent the induction of IFN-stimulated genes, such as IFIT-1. This finding outlines the possible impact of resminostat on cellular innate immunity, being instrumental in overcoming resistances to MeV-mediated viral oncolysis. Thus, our results support the onset of epi-virotherapeutic clinical trials in patients exhibiting advanced stages of HCC.

Enhanced killing of therapy‐induced senescent tumor cells by oncolytic measles vaccine viruses

Therapy-induced senescence (TIS) as a permanent growth arrest can be induced by various stimuli, including anticancer compounds. TIS emerged as a promising strategy to overcome resistance phenomena. However, senescent cancer cells might regain proliferation activity in vivo or even secrete tumor-promoting cytokines. Therefore, successful exploitation of TIS in cancer treatment simultaneously requires the development of effective strategies to eliminate senescent cancer cells. Virotherapy aims to selectively hit tumor cells, thus a combination with senescence-inducing drugs was explored. As a model, we chose measles vaccine virus (MeV), which does not interfere with cellular senescence by itself. In different tumor cell types, such as hepatoma, pancreatic and mammary gland carcinoma, we demonstrate efficient viral replication and lysis after TIS by gemcitabine, doxorubicin or taxol. Applying real time imaging, we even found an accelerated lysis of senescent cancer cells, supporting an enhanced viral replication with an increase in cell-associated and released infectious MeV particles. In summary, we show as a proof-of-concept that senescent tumor cells can be efficiently exploited as virus host cells by oncolytic MeV. These observations open up a new field for preclinical and clinical research to further investigate TIS and oncolytic viruses as an attractive combinatorial future treatment approach.

An armed oncolytic measles vaccine virus eliminates human hepatoma cells independently of apoptosis

Due to late diagnosis and a pronounced chemoresistance, most patients with hepatocellular carcinoma (HCC) have an overall poor prognosis. Measles vaccine viruses (MeV) have been shown to possess anti-tumor properties and their efficacy has been enhanced by arming with suicide genes. To test armed MeV for the treatment of HCC, we equipped it with the suicide gene Super-cytosine deaminase (SCD) and tested the efficacy in cell culture and in a mouse xenograft model of human HCC. Prodrug conversion was investigated in cell culture and quantified by high-performance liquid chromatography. We observed a strong oncolytic activity of MeV-SCD against human HCC in vitro and in vivo. The prodrug was efficiently converted in infected cells leading to a significant enhancement of the cytotoxic effect. Treatment of HCC xenografts with MeV caused long-term virus replication in tumor tissue. We show that the suicide gene therapy induces an apoptosis-like cell death but is not dependent on intact apoptosis pathways. These results demonstrate that MeV-based suicide gene therapy is a promising novel therapy regimen for HCC overcoming resistance towards conventional therapy. The independence from apoptosis raises hopes for the treatment of patients whose tumor cells exert defects in this cell death mechanism.

Enhanced killing of ovarian carcinoma using oncolytic measles vaccine virus armed with a yeast cytosine deaminase and uracil phosphoribosyltransferase

ObjectiveTo preclinical assess the feasibility of combining oncolytic measles vaccine virus (MeV) with suicide gene therapy for ovarian cancer treatment. MethodsWe genetically engineered a recombinant MeV armed with a yeast-derived bifunctional suicide gene that encodes for cytosine deaminase and uracil phosphoribosyltransferase (MeV-SCD). From this suicide gene, a chimeric protein is produced that converts the non-toxic prodrug 5-fluorocytosine (5-FC) into highly cytotoxic 5-fluorouracil (5-FU) and directly into 5-fluorouridine monophosphate (5-FUMP) thereby bypassing an important mechanism of chemoresistance to 5-FU. ResultsMeV-SCD was demonstrated to infect, replicate in and effectively lyse not only human ovarian cancer cell lines, but also primary tumor cells (albeit at lower efficiencies) that were derived from malignant ascites of ovarian cancer patients. Addition of the prodrug 5-FC significantly enhanced cell killing. Importantly, precision-cut tumor slices of human ovarian cancer patient specimens were efficiently infected with MeV-SCD. The prodrug-converting enzyme SCD was expressed by all infected tumor slices, thereby ensuring provision of the suicide gene arming function in patient-derived materials. ConclusionsWith respect to safety and therapeutic impact, arming of oncolytic measles vaccine virus warrants further clinical investigation for ovarian cancer treatment.

An oncolytic measles vaccine virus armed with a suicide gene eliminates human hepatoma cells independently of apoptosis

An oncolytic measles vaccine virus armed with a suicide gene eliminates human hepatoma cells independently of apoptosis

Virotherapeutic treatment of cholangiocarcinoma using a novel armed oncolytic measles vaccine virus

Virotherapeutic treatment of cholangiocarcinoma using a novel armed oncolytic measles vaccine virus

A novel armed oncolytic measles vaccine virus for the treatment of cholangiocarcinoma

A novel armed oncolytic measles vaccine virus for the treatment of cholangiocarcinoma

Armed oncolytic measles vaccine virus–a novel therapeutic agent for virotherapy of sarcomas of gastrointestinal and non-gastrointestinal origin

Armed oncolytic measles vaccine virus–a novel therapeutic agent for virotherapy of sarcomas of gastrointestinal and non-gastrointestinal origin

Treatment of hepatocellular carcinoma with a novel suicide gene-expressing oncolytic measles vaccine virus

Introduction: Oncolytic viruses are promising agents under investigation as cancer therapeutics. These replication competent viruses selectively infect and kill cancer cells. However, early clinical results point out that oncolysis achieved by unmodified vectors seems to be not sufficiently effective. To enhance cell killing, oncolytic viruses can be engineered to express suicide genes which convert non-toxic substances (prodrugs) into toxic metabolites. Aims: Development of new anti-HCC regimens based on oncolytic measles vaccine virus (MeV) expressing optimized suicide genes. Methods: We have generated (i) MeV vectors expressing the suicide gene SCD (MeV-SCD), a fusion of cytosine deaminase and uracil phosphoribosyltransferase and (ii) a MeV vector expressing VP22SCD (MeV-VP22SCD) which is a fusion of SCD to the intercellular transport protein VP22. Different hepatoma cell lines were used to test the susceptibility to both, MeV oncolysis and the suicide gene therapy. Conversion of 5-FC to 5-FU (5-fluorouracil) was demonstrated by HPLC. Cell death pathways of the infected cells were examined. In addition to these in vitro experiments, we also tested the effect of MeV-SCD in vivo. Results: All cell lines were found to be susceptible to MeV. Cell killing was enhanced by treatment with 5-FC. Comparison of the different MeV vectors suggests that VP22 does not further enhance the bystander effect in the context of an oncolytic virus with fusogenic glycoproteins. Of note, survival of tumor bearing mice was significantly prolonged by combinatorial treatment with MeV-SCD + 5-FC. Conclusion: Oncolytic virotherapy represents a promising addition for multimodal oncological concepts. By employing the SCD/5-FC system in combination with cytolytic MeV vectors, partial resistances of HCC to oncolysis can be overcome and the efficiency of MeV-mediated oncolysis can be enhanced significantly. On this basis, clinical phase I/II trials are currently under development.

Armed oncolytic measles vaccine virus – a novel therapeutic agent for virotherapy of solid tumors

Armed oncolytic measles vaccine virus – a novel therapeutic agent for virotherapy of solid tumors

A novel suicide gene-expressing oncolytic measles vaccine virus for the treatment of hepatocellular carcinoma

A novel suicide gene-expressing oncolytic measles vaccine virus for the treatment of hepatocellular carcinoma

Human precision-cut liver tumor slices as a tumor patient-individual predictive test system for oncolytic measles vaccine viruses

Availability of an individualized preselection of oncolytic viruses to be used for virotherapy of tumor patients would be of great help. Using primary liver tumor resection specimens we evaluated the precision-cut liver slice (PCLS) technology as a novel in vitro test system for characterization of paramount tumor infection parameters of individual patients. PCLS slices from resection specimens of 20 liver tumor patients were cultivated in vitro for up to 5 days and infected with 5 different oncolytic measles vaccine virus (MeV) strains. Effectiveness of tumor infection was monitored by viral nucleocapsid (N) protein detection in immunofluorescence staining or Western blot analysis or by detection of GFP marker gene expression. MeV spreading in PCLS cultures was visualized by confocal microscopy. Oncolytic MeV vaccine particles were demonstrated to efficiently infect PCLS slices originating from different primary and secondary tumors of the liver with MeV strains Moraten/Edmonston Zagreb and AIK-C showing highest infection rates (75% of all tested tumor specimens). Employing mixed liver tissue slices (exhibiting both tumorous and non-tumorous tissue areas on one and the same sample) a distinct tumor area favouring pattern of MeV infections was observed being in accordance with our finding that primary human hepatocytes are also permissive to MeV particles, albeit at a much lower rate and with a much less pronounced cytopathic effect. Furthermore, confocal microscopy demonstrated virus penetration throughout tumor tissues into deep cell layers. In conclusion, the PCLS technology is suitable to perform a tumor-patient individualized preselection of oncolytic agents prior to clinical virotherapeutic applications.