Metabolic changes during wheat microspore embryogenesis induction using the highly responsive cultivar Svilena.

Androgenetically-derived haploids can be obtained by inducing embryogenesis in microspores. Thus, full homozygosity is achieved in a single generation, oppositely to conventional plant breeding programs. Here, the metabolite profile of embryogenic microspores of Triticum aestivum was acquired and integrated with transcriptomic existing data from the same samples in an effort to identify the key metabolic processes occurring during the early stages of microspore embryogenesis.

Robust envelope exchange platform for oncolytic measles virus.

The use of oncolytic viruses (OV) to precisely target and eliminate tumors ('virotherapy') is a rapidly evolving therapeutic approach to treating cancer. A major obstacle in virotherapy, especially for systemic administration, is the host's immune response towards the OV. In the case of measles virus (MeV), most individuals have been immunized against this agent leading to pre-existing neutralizing antibodies that can impair OV delivery to the tumor.

MicroRNA-sensitive oncolytic measles virus for chemovirotherapy of pancreatic cancer.

Advanced pancreatic cancer is characterized by few treatment options and poor outcomes. Oncolytic virotherapy and chemotherapy involve complementary pharmacodynamics and could synergize to improve therapeutic efficacy. Likewise, multimodality treatment may cause additional toxicity, and new agents have to be safe.

Sequencing of serially passaged measles virus affirms its genomic stability and reveals a nonrandom distribution of consensus mutations.

Oncolytic virotherapy is an emerging treatment option for numerous cancers, with several virus families currently being evaluated in clinical trials. More specifically, vaccine-strain measles virus has arisen as a promising candidate for the treatment of different tumour types in several early clinical trials. Replicating viruses, and especially RNA viruses without proofreading polymerases, can rapidly adapt to varying environments by selecting quasispecies with advantageous genetic mutations.

Enhanced Control of Oncolytic Measles Virus Using MicroRNA Target Sites.

Measles viruses derived from the live-attenuated Edmonton-B vaccine lineage are currently investigated as novel anti-cancer therapeutics. In this context, tumor specificity and oncolytic potency are key determinants of the therapeutic index. Here, we describe a systematic and comprehensive analysis of a recently developed post-entry targeting strategy based on the incorporation of microRNA target sites (miRTS) into the measles virus genome.

A Tupaia paramyxovirus vector system for targeting and transgene expression.

Viruses from the diverse family of Paramyxoviridae include important pathogens and are applied in gene therapy and for cancer treatment. The Tupaia paramyxovirus (TPMV), isolated from the kidney of a tree shrew, does not infect human cells and neutralizing antibodies against other Paramyxoviridae do not cross-react with TPMV. Here, we present a vector system for de novo generation of infectious TPMV that allows for insertion of additional genes as well as targeting using antibody single-chain variable fragments.

Analysis of wheat microspore embryogenesis induction by transcriptome and small RNA sequencing using the highly responsive cultivar "Svilena".

Background: Microspore embryogenesis describes a stress-induced reprogramming of immature male plant gametophytes to develop into embryo-like structures, which can be regenerated into doubled haploid plants after whole genome reduplication. This mechanism is of high interest for both research as well as plant breeding. The objective of this study was to characterize transcriptional changes and regulatory relationships in early stages of cold stress-induced wheat microspore embryogenesis by transcriptome and small RNA sequencing using a highly responsive cultivar.

Moving oncolytic viruses into the clinic: clinical-grade production, purification, and characterization of diverse oncolytic viruses.

Oncolytic viruses (OVs) are unique anticancer agents based on their pleotropic modes of action, which include, besides viral tumor cell lysis, activation of antitumor immunity. A panel of diverse viruses, often genetically engineered, has advanced to clinical investigation, including phase 3 studies. This diversity of virotherapeutics not only offers interesting opportunities for the implementation of different therapeutic regimens but also poses challenges for clinical translation.

CTLA-4 and PD-L1 checkpoint blockade enhances oncolytic measles virus therapy.

We hypothesized that the combination of oncolytic virotherapy with immune checkpoint modulators would reduce tumor burden by direct cell lysis and stimulate antitumor immunity. In this study, we have generated attenuated Measles virus (MV) vectors encoding antibodies against CTLA-4 and PD-L1 (MV-aCTLA-4 and MV-aPD-L1). We characterized the vectors in terms of growth kinetics, antibody expression, and cytotoxicity in vitro.

MicroRNA-mediated multi-tissue detargeting of oncolytic measles virus.

Precise oncotropism is required for successful systemic administration of next-generation oncolytic measles viruses (MVs). We have previously established a system for efficient post-entry targeting by insertion of synthetic microRNA target sites (miRTS) into the MV genome, thereby repressing replication in the presence of cognate microRNAs. Thus, differential expression of microRNAs, as frequently observed in normal compared with malignant tissues, can be exploited to increase vector specificity and safety.

Attenuated and protease-profile modified sendai virus vectors as a new tool for virotherapy of solid tumors.

Multiple types of oncolytic viruses are currently under investigation in clinical trials. To optimize therapeutic outcomes it is believed that the plethora of different tumor types will require a diversity of different virus types. Sendai virus (SeV), a murine parainfluenza virus, displays a broad host range, enters cells within minutes and already has been applied safely as a gene transfer vector in gene therapy patients.

Artificial riboswitches for gene expression and replication control of DNA and RNA viruses.

Aptazymes are small, ligand-dependent self-cleaving ribozymes that function independently of transcription factors and can be customized for induction by various small molecules. Here, we introduce these artificial riboswitches for regulation of DNA and RNA viruses. We hypothesize that they represent universally applicable tools for studying viral gene functions and for applications as a safety switch for oncolytic and live vaccine viruses.

Evaluation of a novel immunogenic vaccine platform based on a genome replication-deficient Sendai vector.

We developed a novel vaccine platform based on a paramyxoviral, genome replication-deficient Sendai virus vector that can express heterologous genes inserted into the genome. To validate the novel approach in vivo, we generated a combined vaccine candidate against human respiratory syncytial virus (RSV) and human parainfluenza virus type 3 (PIV3). The present study compares two different methods of displaying heterologous antigens: (i) the RSV fusion (F) protein, encoded as a secretable version in an additional transcription unit, serves as an antigen only after being expressed in infected cells; (ii) PIV3 fusion (F) and hemagglutinin-neuraminidase (HN) genes, replacing Sendai counterparts in the vector genome, are also expressed as structural components on the surface of vaccine particles.

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.

Granulocyte-macrophage colony-stimulating factor-armed oncolytic measles virus is an effective therapeutic cancer vaccine.

Oncolytic measles viruses (MV) derived from the live attenuated vaccine strain have been engineered for increased antitumor activity, and are currently under investigation in clinical phase 1 trials. Approaches with other viral vectors have shown that insertion of immunomodulatory transgenes enhances the therapeutic potency. In this study, we engineered MV for expression of the cytokine granulocyte-macrophage colony-stimulating factor (GM-CSF).

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

Cholangiocarcinoma (CC) is curable only in early stages by complete surgical resection. Thus, in advanced disease stages in which a complete removal of the tumor mass is no longer possible and palliative chemotherapy achieves only modest success, therapeutics employing new methods of action are desperately needed. Oncolytic viruses employed in clinical studies have been shown to spread preferentially in cancer cells.

Chemovirotherapy of malignant melanoma with a targeted and armed oncolytic measles virus.

Effective treatment modalities for advanced melanoma are desperately needed. An innovative approach is virotherapy, in which viruses are engineered to infect cancer cells, resulting in tumor cell lysis and an amplification effect by viral replication and spread. Ideally, tumor selectivity of these oncolytic viruses is already determined during viral cell binding and entry, which has not been reported for melanoma.

Evaluation of nucleocapsid and phosphoprotein p functionality as critical factors during the early phase of paramyxoviral infection.

In the beginning of a paramyxovirus infection after cell entry viral survival depends on efficient primary (1°) transcription and on the stability of only one input nucleocapsid. Here we examined the influence of the viral polymerase co-factor phosphoprotein P on the very early phase of an infection, i.e.

Chemovirotherapy for head and neck squamous cell carcinoma with EGFR-targeted and CD/UPRT-armed oncolytic measles virus.

First-line treatment of recurrent and/or refractory head and neck squamous cell carcinoma (HNSCC) is based on platinum, 5-fluorouracil (5-FU) and the monoclonal antiEGFR antibody cetuximab. However, in most cases this chemoimmunotherapy does not cure the disease, and more than 50% of HNSCC patients are dying because of local recurrence of the tumors. In the majority of cases, HNSCC overexpress the epidermal growth factor receptor (EGFR), and its presence is associated with a poor outcome.

Armed and targeted measles virus for chemovirotherapy of pancreatic cancer.

No curative therapy is currently available for locally advanced or metastatic pancreatic cancer. Therefore, new therapeutic approaches must be considered. Measles virus (MV) vaccine strains have shown promising oncolytic activity against a variety of tumor entities.

MicroRNA-sensitive oncolytic measles viruses for cancer-specific vector tropism.

Oncolytic measles viruses (MV) derived from the live attenuated vaccine strain have been engineered for increased tumor-cell specificity, and are currently under investigation in clinical trials including a phase I study for glioblastoma multiforme (GBM). Recent preclinical studies have shown that the cellular tropism of several viruses can be controlled by inserting microRNA-target sequences into their genomes, thereby inhibiting spread in tissues expressing cognate microRNAs. Since neuron-specific microRNA-7 is downregulated in gliomas but highly expressed in normal brain tissue, we engineered a microRNA-sensitive virus containing target sites for microRNA-7 in the 3'-untranslated region of the viral fusion gene.

Recombinant Sendai virus induces T cell immunity against respiratory syncytial virus that is protective in the absence of antibodies.

Respiratory syncytial virus (RSV) causes severe respiratory disease in infants and a vaccine is highly desirable. The fusion (F) protein of RSV is an important vaccine target, but the contribution of F-specific T cells to successful vaccination remains unclear. We studied the immune response to vaccination of mice with a recombinant Sendai virus expressing RSV F (rSeV F).

De novo synthesis of N and P proteins as a key step in Sendai virus gene expression.

Among the members of the paramyxovirus family, the transcription process and the components involved have been studied under in vitro conditions thus far. Here, we reexamined the function of the viral RNA-dependent RNA polymerase through infection studies with Sendai virus (SeV) N and P deletion (Delta) mutants. To elucidate solely transcription-specific processes, all virus mutants also were rendered deficient in genome replication.