Restriction of Replication of Oncolytic Herpes Simplex Virus with a Deletion of γ34.5 in Glioblastoma Stem-Like Cells.

Oncolytic viruses, including herpes simplex viruses (HSVs), are a new class of cancer therapeutic engineered to infect and kill cancer cells while sparing normal tissue. To ensure that oncolytic HSV (oHSV) is safe in the brain, all oHSVs in clinical trial for glioma lack the γ34.5 genes responsible for neurovirulence. However, loss of γ34.5 attenuates growth in cancer cells. Glioblastoma (GBM) is a lethal brain tumor that is heterogeneous and contains a subpopulation of cancer stem cells, termed GBM stem-like cells (GSCs), that likely promote tumor progression and recurrence. GSCs and matched serum-cultured GBM cells (ScGCs), representative of bulk or differentiated tumor cells, were isolated from the same patient tumor specimens. ScGCs are permissive to replication and cell killing by oHSV with deletion of the γ34.5 genes (γ34.5- oHSV), while patient-matched GSCs were not, implying an underlying biological difference between stem and bulk cancer cells. GSCs specifically restrict the synthesis of HSV-1 true late (TL) proteins, without affecting viral DNA replication or transcription of TL genes. A global shutoff of cellular protein synthesis also occurs late after γ34.5- oHSV infection of GSCs but does not affect the synthesis of early and leaky late viral proteins. Levels of phosphorylated eIF2α and eIF4E do not correlate with cell permissivity. Expression of Us11 in GSCs rescues replication of γ34.5- oHSV. The difference in degrees of permissivity between GSCs and ScGCs to γ34.5- oHSV illustrates a selective translational regulatory pathway in GSCs that may be operative in other stem-like cells and has implications for creating oHSVs.IMPORTANCE Herpes simplex virus (HSV) can be genetically engineered to endow cancer-selective replication and oncolytic activity. γ34.5, a key neurovirulence gene, has been deleted in all oncolytic HSVs in clinical trial for glioma. Glioblastoma stem-like cells (GSCs) are a subpopulation of tumor cells thought to drive tumor heterogeneity and therapeutic resistance. GSCs are nonpermissive for γ34.5- HSV, while non-stem-like cancer cells from the same patient tumors are permissive. GSCs restrict true late protein synthesis, despite normal viral DNA replication and transcription of all kinetic classes. This is specific for true late translation as early and leaky late transcripts are translated late in infection, notwithstanding shutoff of cellular protein synthesis. Expression of Us11 in GSCs rescues the replication of γ34.5- HSV. We have identified a cell type-specific innate response to HSV-1 that limits oncolytic activity in glioblastoma.

Effect of γ34.5 deletions on oncolytic herpes simplex virus activity in brain tumors.

The ICP34.5 protein of herpes simplex virus (HSV) is involved in many aspects of viral pathogenesis; promoting neurovirulence, inhibiting interferon-induced shutoff of protein synthesis, interacting with PCNA and TBK1, inhibiting dendritic cell (DC) maturation, and binding to Beclin 1 to interfere with autophagy. Because of its key role in neuropathogenicity, the γ34.5 gene is deleted in all oncolytic HSVs (oHSVs) currently in clinical trial for treating malignant gliomas. Unfortunately, deletion of γ34.5 attenuates virus replication in cancer cells, especially human glioblastoma stem cells (GSCs). To develop new oHSVs for use in the brain and that replicate in GSCs, we explored the effect of deleting the γ34.5 Beclin 1 binding domain (BBD). To ensure cancer selectivity and safety, we inactivated the ICP6 gene (UL39, large subunit of ribonucleotide reductase), constructing ICP6 mutants with different γ34.5 genotypes: Δ68HR-6, intact γ34.5; Δ68H-6, γ34.5 BBD deleted; and 1716-6, γ34.5 deleted. Multimutated Δ68H-6 exhibited minimal neuropathogenicity in HSV-1-susceptible mice, as opposed to Δ68H and Δ68HR-6. It replicated well in human glioma cell lines and GSCs, effectively killing cells in vitro and prolonging survival of mice bearing orthotopic brain tumors. In contrast, 1716 and 1716-6 barely replicated in GSCs. Infection of glioma cells with Δ68H-6 and 1716-6 induced autophagy and increased phosphorylation of eIF2α, while inhibition of autophagy, by Beclin 1 short hairpin RNA (shRNA) knockdown or pharmacological inhibition, had no effect on virus replication or phosphorylated eIF2α (p-eIF2α) levels. Thus, Δ68H-6 represents a new oHSV vector that is safe and effective against a variety of brain tumor models.

Fluid-Screen as a real time dielectrophoretic method for universal microbial capture.

Bacterial culture methods, e.g. Plate Counting Method (PCM), are a gold standard in the assessment of microbial contamination in multitude of human industries. They are however slow, labor intensive, and prone to manual errors. Dielectrophoresis (DEP) has shown great promise for particle separation for decades; however, it has not yet been widely applied in routine laboratory setting. This paper provides an overview of a new DEP microbial capture and separation method called Fluid-Screen (FS), that achieves very fast, efficient, reliable and repeatable capture and separation of microbial cells. Method verification experiments demonstrated that the FS system captured 100% of bacteria in test samples, a capture efficiency much higher than previously reported for similar technology. Data generated supports the superiority of the FS method as compared to the established Plate Counting Method (PCM), that is routinely used to detect bacterial contamination in healthcare, pharmacological and food industries. We demonstrate that the FS method is universal and can capture and separate different species of bacteria and fungi to viruses, from various sample matrices (i.e. human red blood cells, mammalian cells).

Combinatorial Effects of VEGFR Kinase Inhibitor Axitinib and Oncolytic Virotherapy in Mouse and Human Glioblastoma Stem-Like Cell Models.

Purpose: Glioblastoma (GBM), a fatal brain cancer, contains a subpopulation of GBM stem-like cells (GSCs) that contribute to resistance to current therapy. Angiogenesis also plays a key role in GBM progression. Therefore, we developed a strategy to target the complex GBM microenvironment, including GSCs and tumor vasculature.Experimental Design: We evaluated the cytotoxic effects of VEFGR tyrosine kinase inhibitor (TKI) axitinib in vitro and then tested antitumor efficacy of axitinib in combination with oncolytic herpes simplex virus (oHSV) expressing antiangiogenic cytokine murine IL12 (G47Δ-mIL12) in two orthotopic GSC-derived GBM models: patient-derived recurrent MGG123 GSCs, forming vascular xenografts in immunodeficient mice; and mouse 005 GSCs, forming syngeneic tumors in immunocompetent mice.Results: GSCs form endothelial-like tubes and were sensitive to axitinib. G47Δ-mIL12 significantly improved survival, as did axitinib, while dual combinations further extended survival significantly compared with single therapies alone in both models. In MGG123 tumors, axitinib was effective only at high doses (50 mg/kg), alone and in combination with G47Δ-mIL12, and this was associated with greatly decreased vascularity, increased macrophage infiltration, extensive tumor necrosis, and PDGFR/ERK pathway inhibition. In the mouse 005 model, antiglioma activity, after single and combination therapy, was only observed in immunocompetent mice and not the T-cell-deficient athymic mice. Interestingly, immune checkpoint inhibition did not improve efficacy.Conclusions: Systemic TKI (axitinib) beneficially combines with G47Δ-mIL12 to enhance antitumor efficacy in both immunodeficient and immunocompetent orthotopic GBM models. Our results support further investigation of TKIs in combination with oHSV for GBM treatment. Clin Cancer Res; 24(14); 3409-22. ©2018 AACR.

Regulation of beta1 integrin expression in endothelial cells by chimeric tRNA(Val) ribozyme.

To downregulate expression of the beta1 integrin subunit in endothelial cells, plasmid encoding the ribozyme cassette containing hammerhead ribozyme flanked at the 5' terminus by tRNA(Val) and at the 3' terminus by constitutive transport element sequences was constructed. When used to transfect immortalized human endothelial cell line EA.hy 926, it selectively blocked the synthesis of the beta1 integrin subunit and thus inhibited migration and proliferation of the cells. Thus, this construct may be a valuable tool to control the proangiogenic phenotype of stimulated endothelial cells.

Prospect and progress of oncolytic viruses for treating peripheral nerve sheath tumors.

INTRODUCTION: Peripheral nerve sheath tumors (PNSTs) are an assorted group of neoplasms originating from neuroectoderm and growing in peripheral nerves. Malignant transformation leads to a poor prognosis and is often lethal. Current treatment of PNSTs is predominantly surgical, which is often incomplete or accompanied by significant loss of function, in conjunction with radiotherapy and/or chemotherapy, for which the benefits are inconclusive. Oncolytic viruses (OVs) efficiently kill tumor cells while remaining safe for normal tissues, and are a novel antitumor therapy for patients with PNSTs. AREAS COVERED: Because of the low efficacy of current treatments, new therapies for PNSTs are needed. Pre-clinically, OVs have demonstrated efficacy in treating PNSTs and perineural tumor invasion, as well as safety. We will discuss the various PNSTs and their preclinical models, and the OVs being tested for their treatment, including oncolytic herpes simplex virus (HSV), adenovirus (Ad), and measles virus (MV). OVs can be 'armed' to express therapeutic transgenes or combined with other therapeutics to enhance their activity. EXPERT OPINION: Preclinical testing of OVs in PNST models has demonstrated their therapeutic potential and provided support for clinical translation. Clinical studies with other solid tumors have provided evidence that OVs are safe in patients and efficacious. The recent successful completion of a phase III clinical trial of oncolytic HSV paves the way for oncolytic virotherapy to enter clinical practice.

Loss of FHIT expression in gastric mucosa of patients with family histories of gastric cancer and Helicobacter pylori infection.

AIM: To answer the question whether FHIT gene expression is affected by the family history of gastric carcinoma and the presence of Helicobacter pylori (H pylori) in the gastric mucosa of patients with dyspepsia. METHODS: FHIT gene expression in two different topographic sites of the gastric mucosa of twenty-one patients with dyspepsia and with or without familial gastric carcinoma, infected or not infected with H pylori, was evaluated by reverse transcription-PCR (RT-PCR) and IMAGE QUANT methods. A rapid urease test and histopathological examination were used to determine H pylori colonization. RESULTS: In the gastric mucosa of patients with family histories of gastric carcinoma, the amount of FHIT protein mRNA was reduced down to 32%, and for patients with H pylori colonization, to 24% in comparison to controls with dyspepsia and without cancer in the family. FHIT expression was independent of the topography of specimens (corpus vs antrum), and for the control patients it was less sensitive to infection with H pylori. A considerable statistical difference in FHIT levels was observed in the gastric mucosa from the corpus of patients with family histories of gastric carcinoma in respect to H pylori colonization (P = 0.06). Macroscopic evaluation of the gastric mucosa demonstrated that pathologic changes classified according to the Sydney system had no significant influence on FHIT expression within each tested group of patients. CONCLUSION: Loss of FHIT expression was observed in patients with dyspepsia and family histories of gastric carcinoma, especially those infected with H pylori. Such results may constitute an early indication of the development of gastric carcinoma, which is associated with family factors including heredity and H pylori infection. The loss of the FHIT gene may serve as a marker for early diagnosis and prevention of gastric carcinoma, especially in context of early monitoring of H pylori infection in individuals with a record of familial stomach cancer.

Synthesis of dinucleoside (N3'-->MeP5') methanephosphonamidates.

[structure: see text] Three different approaches were used for the synthesis of dinucleoside methanephosphonamidates [3'-NH-P(O)(CH3)O-5'], starting from dichloromethylphosphine or dichloromethanephosphonate as the phosphorus-containing moiety. 5'-DMT-3'-amino-3'-deoxythymidine and N(4)-benzoyl-5'-DMT-3'-amino-2',3'-dideoxycytidine were used as the aminonucleoside precursors and the respective 3'-protected nucleosides (thymidine or N(4)-benzoyl-2'-deoxycytidine) as the 5'-hydroxyl reagents.

Treatment of orthotopic malignant peripheral nerve sheath tumors with oncolytic herpes simplex virus.

BACKGROUNDS: Malignant peripheral nerve sheath tumors (MPNSTs) are an aggressive and often lethal sarcoma that frequently develops in patients with neurofibromatosis type 1 (NF1). We developed new preclinical MPNST models and tested the efficacy of oncolytic herpes simplex viruses (oHSVs), a promising cancer therapeutic that selectively replicates in and kills cancer cells. METHODS: Mouse NF1(-) MPNST cell lines and human NF1(-) MPNST stemlike cells (MSLCs) were implanted into the sciatic nerves of immunocompetent and athymic mice, respectively. Tumor growth was followed by external measurement and sciatic nerve deficit using a hind-limb scoring system. Oncolytic HSV G47Δ as well as "armed" G47Δ expressing platelet factor 4 (PF4) or interleukin (IL)-12 were injected intratumorally into established sciatic nerve tumors. RESULTS: Mouse MPNST cell lines formed tumors with varying growth kinetics. A single intratumoral injection of G47Δ in sciatic nerve tumors derived from human S462 MSLCs in athymic mice or mouse M2 (37-3-18-4) cells in immunocompetent mice significantly inhibited tumor growth and prolonged survival. Local IL-12 expression significantly improved the efficacy of G47Δ in syngeneic mice, while PF4 expression prolonged survival. Injection of G47Δ directly into the sciatic nerve of athymic mice resulted in only mild symptoms that did not differ from phosphate buffered saline control. CONCLUSIONS: Two new orthotopic MPNST models are described, including in syngeneic mice, expanding the options for preclinical testing. Oncolytic HSV G47Δ exhibited robust efficacy in both immunodeficient and immunocompetent MPNST models while maintaining safety. Interleukin-12 expression improved efficacy. These studies support the clinical translation of G47Δ for patients with MPNST.

Correlation of structure and activity of short hairpin RNA.

To explore the relationship between the structure of the precursor of short hairpin RNA (shRNA) and the activity of the shRNA-expression vector, 32 kinds of vectors, which expressed shRNAs with different flanking sequences, were tested. Addition of the poly(A) enhanced the activity of shRNA driven by U6 promoter. The activity of poly (A) tagged U6 promoter driven shRNA was lower than that of the CMV promoter driven constructs, in spite of the identical sequence of both transcripts. The result indicated that it is not only the structure but also the cascade of the transcripts that affects the RNAi activity.

Efficient inhibition of beta-secretase gene expression in HEK293 cells by tRNAVal-driven and CTE-helicase associated hammerhead ribozymes.

The beta-amyloid peptide (Abeta) is a major component of toxic amyloid plaques found in the brains of patients with Alzheimer's disease. Abeta is liberated by sequential cleavage of amyloid precursor protein (APP) by beta- and gamma-secretases. The level of Abeta depends directly on the hydrolytic activity of beta-secretase. Therefore, beta-secretase is an excellent target for drug design. An approach based on RNA-cleaving ribozymes was developed to control expression of beta-secretase. Two sites of mRNA coding beta-site APP cleaving enzyme were chosen as target sequences for endogenously delivered ribozymes. The ribozyme cassette was designed to constitute a catalytic hammerhead core and substrate recognition arms, flanked at the 5'-terminus by tRNAVal and at the 3'-terminus by constitutive transport element sequences. Ribozyme cassettes were cloned into a pUC19 plasmid and used for transient transfection of HEK293 cells. We demonstrate that such ribozymes efficiently inhibit beta-secretase gene expression at both the mRNA (up to 95%) and the protein (up to 90%) levels. Inhibition of beta-site APP cleaving enzyme activity directly influences the intra- and extracellular population of Abeta peptide. Therefore, such ribozymes may be considered as molecular tools for silencing the beta-secretase activity, and further, as therapeutic agents for anti-amyloid treatment.

Modulation of beta-secretase gene expression by action of catalytic nucleic acids.

Two sites of the initial translation sequence of beta-secretase (BACE) mRNA were chosen as targets for endogenously delivered hammerhead ribozymes. Ribozyme cassettes coding a catalytic core, flanked by the 5'-tRNA(Val) and the 3'-CTE (constitutive transport element) sequences, were cloned into a pUC119 plasmid and used for transfection of transformed primary human embryonal kidney (HEK293) cells. The ribozymes express in the test cells and inhibit beta-secretase gene biosynthesis on the level of mRNA (up to 95%) and on the level of protein (up to 90%) and thus may be considered as therapeutic inhibitors of beta-secretase activity.