A simple and efficient method for purification of infectious recombinant adenovirus

An automated and high-throughput approach for enhanced precision of adenoviral titering

Accurate quantification of viral vectors and vaccines is a crucial step required before any downstream use of virus preparations. The conventional immunocytochemistry-based method of adenovirus quantification has been widely used, but there are many areas for improvement toward accuracy and resource consumption savings to reduce viral miscalculation and wastage of vaccination materials. In this work, a one-step approach is implemented for optimized adenoviral quantification that uses a single antibody coupled with automated, high-throughput image acquisition and subsequent batch analysis. First, cells are infected with the adenovirus of interest and stained using the Hexon protein. Then, multichannel automated image acquisition via the Invitrogen EVOS M7000 Imaging System is performed. Last is an automated large batch analysis of acquired images via the EVOS Analysis Software, accomplished via precise training of the software allowing for virus infection quantification and additional parameters (counts, circularity, area and intensity of targets). It was found that the implemented approach yielded precise and accurate quantification of both oncolytic viral vaccines and gene therapy vectors in a time- and resource-effective manner when compared with conventional methodologies.

Human adenovirus type 7 (HAdV-7) infection induces pulmonary vascular endothelial injury through the activation of endothelial autophagy

BACKGROUND

HAdV-7 is a prevalent pathogen that can cause severe pneumonia in children. Previous studies have shown a significant increase in serum levels of vascular permeability factor (VPF/VEGF) and viral load in pediatric patients with fatal HAdV-7 infection, suggesting potential damage to the pulmonary vascular endothelium. Further research is necessary to elucidate the underlying mechanism.

METHODS

The human lung microvascular endothelial cell line-5a and human CD46 mice were used for in vitro and in vivo experiments, respectively. RNA-seq was employed for correlative omics analysis. Viral infection and copy status were examined using transmission electron microscopy to observe virus particles, immunofluorescence to detect the viral protein Hexon, and qPCR to assess HAdV-7 fiber gene copies. Various methods, including ELISAs for VEGF and other injury markers, the CCK8 assay for cell viability, and flow cytometry for endothelium numbers, were employed to evaluate endothelial damage. Acute lung injury severity was evaluated by scoring pathological inflammation and measuring pulmonary vascular permeability. Autophagy activation was assessed by observing autophagosomes and validating marker proteins.

RESULTS

GSEA analysis showed significant enrichment of gene sets related to endothelial functions (barrier, defense, and regeneration) and ALI in the HAdV-7-infected group. GO analysis indicated an enrichment of autophagy-related pathways linked to cell death. Subsequently, successful signs of HAdV-7 infection and replication were observed in the endothelium, including cytopathic effects, intracellular virions, and increased HAdV-7 fiber gene copies. Endothelial injury, including mitochondrial damage, decreased endothelium, and elevated levels of endothelial injury markers such as VEGF, sICAM-1, sVCAM-1, E-selectin, ESM1, MCP1, and IL1β were observed after HAdV-7 infection. Additionally, evidence of leaky lung blood vessels and ALI was observed, including progressive weight loss, elevated pulmonary vascular permeability, and severe lung consolidation. Furthermore, HAdV-7 infection induced autophagosome formation in the endothelium and triggered complete cell autophagy. Importantly, inhibiting autophagic flux reduced VEGF levels and other endothelial injury markers, decreased viral load, improved cell survival rate, alleviated pulmonary vessel leakage, and mitigated lung inflammation.

CONCLUSIONS

HAdV-7 successfully infects pulmonary vascular endothelium and replicates effectively, causing injury to the endothelium, high VEGF expression and viral load in the serum, as well as ALI/ARDS. Autophagy inhibitors can alleviate endothelial injury, inhibit viral replication, relieve leakage from the vasculature, and reduce lung inflammation.

In vitro assessment of the anti-adenoviral activity of artemisinin and its derivatives

Adenoviral infections, particularly in children, remain a significant public health issue with no approved targeted treatments. Artemisinin and its derivatives, well-known for their use in malaria treatment, have shown antiviral activities in recent studies. However, their efficacy against human adenovirus (HAdV) remains unexplored. This study aimed to assess the activity of artemisinin and its derivatives against HAdV infection in vitro using cell lines and primary cells. Our data revealed that artemisinin exhibited dose-dependent anti-HAdV activity with no apparent cytotoxicity over a wide concentration range. Mechanistically, artemisinin did not affect viral attachment or entry into target cells, nor the viral genome entry into cell nucleus. Instead, it inhibited HAdV through suppression of viral DNA replication. Comparative analysis with its derivatives, artesunate and artemisone, showed distinct cytotoxicity and anti-adenoviral profiles, with artemisone showing superior efficacy and lower toxicity. Further validation using a primary airway epithelial cell model confirmed the anti-adenoviral activity of both artemisinin and artemisone against different virus strains. Together, our findings suggest that artemisinin and its derivatives may be promising candidates for anti-HAdV treatment.

Development of a novel adenovirus serotype 35 vector vaccine possessing an RGD peptide in the fiber knob and the E4 orf 4, 6, and 6/7 regions of adenovirus serotype 5

Adenovirus (Ad) vectors based on human adenovirus serotype 5 (Ad5) have attracted significant attention as vaccine vectors for infectious diseases. However, the effectiveness of Ad5 vectors as vaccines is often inhibited by the anti-Ad5 neutralizing antibodies retained by many adults. To overcome this drawback, we focused on human adenovirus serotype 35 (Ad35) vectors with low seroprevalence in adults. Although Ad35 vectors can circumvent anti-Ad5 neutralizing antibodies, vector yields of Ad35 vectors are often inferior to those of Ad5 vectors. In this study, we developed novel Ad35 vectors containing the Ad5 E4 orf 4, 6, and 6/7 or the Ad5 E4 orf 6 and 6/7 for efficient vector production, and compared their properties. These E4-modified Ad35 vectors efficiently propagated to a similar extent at virus titers comparable to those of Ad5 vectors. An Ad35 vector containing the Ad5 E4 orf 4, 6, and 6/7 mediated more efficient transduction than that containing the Ad5 E4 orf 6 and 6/7 in human cultured cells. Furthermore, insertion of an arginine-glycine-aspartate (RGD) peptide in the fiber region of an Ad35 vector containing the Ad5 E4 orf 4, 6, and 6/7 significantly improved the transgene product-specific antibody production following intramuscular administration in mice. The Ad35 vector containing the RGD peptide mediated efficient vaccine effects even in the mice pre-immunized with an Ad5.

Construction and Stability of All-in-One Adenovirus Vectors Simultaneously Expressing Four and Eight Multiplex Guide RNAs and Cas9 Nickase

CRISPR/Cas9 technology is expected to offer novel genome editing-related therapies for various diseases. We previously showed that an adenovirus vector (AdV) possessing eight expression units of multiplex guide RNAs (gRNAs) was obtained with no deletion of these units. Here, we attempted to construct "all-in-one" AdVs possessing expression units of four and eight gRNAs with Cas9 nickase, although we expected obstacles to obtain complete all-in-one AdVs. The first expected obstacle was that extremely high copies of viral genomes during replication may cause severe off-target cleavages of host cells and induce homologous recombination. However, surprisingly, four units in the all-in-one AdV genome were maintained completely intact. Second, for the all-in-one AdV containing eight gRNA units, we enlarged the E3 deletion in the vector backbone and shortened the U6 promoter of the gRNA expression units to shorten the AdV genome within the adenovirus packaging limits. The final size of the all-in-one AdV genome containing eight gRNA units still slightly exceeded the reported upper limit. Nevertheless, approximately one-third of the eight units remained intact, even upon preparation for in vivo experiments. Third, the genome editing efficiency unexpectedly decreased upon enlarging the E3 deletion. Our results suggested that complete all-in-one AdVs containing four gRNA units could be obtained if the problem of the low genome editing efficiency is solved, and those containing even eight gRNA units could be obtained if the obstacle of the vector size is also removed.

Toward the understanding of DSG2 and CD46 interaction with HAdV-11 fiber, a super-complex analysis

IMPORTANCE

The main limitation of oncolytic vectors is neutralization by blood components, which prevents intratumoral administration to patients. Enadenotucirev, a chimeric HAdV-11p/HAdV-3 adenovirus identified by bio-selection, is a low seroprevalence vector active against a broad range of human carcinoma cell lines. At this stage, there's still some uncertainty about tropism and primary receptor utilization by HAdV-11. However, this information is very important, as it has a direct influence on the effectiveness of HAdV-11-based vectors. The aim of this work is to determine which of the two receptors, DSG2 and CD46, is involved in the attachment of the virus to the host, and what role they play in the early stages of infection.

Identification of functional pathways and potential genes associated with interferon signaling during human adenovirus type 7 infection by weighted gene coexpression network analysis

Human adenovirus type 7 (HAdV-7) can cause severe pneumonia and complications in children. However, the mechanism of pathogenesis and the genes involved remain largely unknown. We collected HAdV-7-infected and mock-infected A549 cells at 24, 48, and 72 hours postinfection (hpi) for RNA sequencing (RNA-Seq) and identified potential genes and functional pathways associated with HAdV-7 infection using weighted gene coexpression network analysis (WGCNA). Based on bioinformatics analysis, 12 coexpression modules were constructed by WGCNA, with the blue, tan, and brown modules significantly positively correlated with adenovirus infection at 24, 48, and 72 hpi, respectively. Functional enrichment analysis indicated that the blue module was mainly enriched in DNA replication and viral processes, the tan module was largely enriched in metabolic pathways and regulation of superoxide radical removal, and the brown module was predominantly enriched in regulation of cell death. qPCR was used to determine transcript abundance of some identified hub genes, and the results were consistent with those from RNA-Seq. Comprehensively analyzing hub genes and differentially expressed genes in the GSE68004 dataset, we identified SOCS3, OASL, ISG15, and IFIT1 as potential candidate genes for use as biomarkers or drug targets in HAdV-7 infection. We propose a multi-target inhibition of the interferon signaling mechanism to explain the association of HAdV-7 infection with the severity of clinical consequences. This study has allowed us to construct a framework of coexpression gene modules in A549 cells infected with HAdV-7, thus providing a basis for identifying potential genes and pathways involved in adenovirus infection and for investigating the pathogenesis of adenovirus-associated diseases.

Development and characterization of a vector system based on the simian adenovirus type 25

Technological versatility and the humoral and cellular immune response induction capacity have conditioned wide spread of adenoviral vectors as vaccine and gene therapy drugs. However, vaccination with Sputnik V made a significant portion of the population immune to the types 5 and 26 (Ad5 and Ad26) recombinant human adenovirus vectors, which are some of the most frequently used bases for candidate vaccines. Today, vaccine designers tend to select alternative adenovirus serotypes as platforms to develop vaccines against new pathogens on. A good example is simian adenovirus type 25 (SAd25), which belongs to subgroup E. It is genetically distant from Ad5 and exhibits extremely low seroprevalence in human beings, which makes it an appealing alternative vaccine vector. The purpose of this work was to design and study a new vaccine platform based on simian adenovirus type 25. We relied on the advanced methods of molecular biology and virology to construct and make recombinant adenoviruses; the phylogenetic analysis in the context of this study was enabled with bioinformatic methods. The resulting recombinant adenoviral vector can effectively replicate itself in the HEK293 cell line (human embryonic kidney cells). This work substantiates the expediency of further investigation into the SAd25 vector as a platform for development of the prevention vaccines against various infectious diseases.

An efficient capture strategy for the purification of human adenovirus type 5 from cell lysates

An efficient capture step for human adenovirus type 5 from cell lysate was developed as an initial virus purification step from cell debris supernatant. Organosilane-based polymer particles were synthesized and experimental monomer screening allowed the selection of appropriate functionalities for the development of particles for virus binding. After elution, virus recoveries of 83 % were obtained with significant reduction of matrix proteins and residual host cell DNA. Therefore, the implemented capture strategy for adenovirus via polymer particles provides a scalable and reproducible approach to reduce time and cost during virus purification processes.

Short term but highly efficient Cas9 expression mediated by excisional system using adenovirus vector and Cre

Genome editing techniques such as CRISPR/Cas9 have both become common gene engineering technologies and have been applied to gene therapy. However, the problems of increasing the efficiency of genome editing and reducing off-target effects that induce double-stranded breaks at unexpected sites in the genome remain. In this study, we developed a novel Cas9 transduction system, Exci-Cas9, using an adenovirus vector (AdV). Cas9 was expressed on a circular molecule excised by the site-specific recombinase Cre and succeeded in shortening the expression period compared to AdV, which expresses the gene of interest for at least 6 months. As an example, we chose hepatitis B, which currently has more than 200 million carriers in the world and frequently progresses to liver cirrhosis or hepatocellular carcinoma. The efficiencies of hepatitis B virus genome disruption by Exci-Cas9 and Cas9 expression by AdV directly (Avec) were the same, about 80–90%. Furthermore, Exci-Cas9 enabled cell- or tissue-specific genome editing by expressing Cre from a cell- or tissue-specific promoter. We believe that Exci-Cas9 developed in this study is useful not only for resolving the persistent expression of Cas9, which has been a problem in genome editing, but also for eliminating long-term DNA viruses such as human papilloma virus.

Aloysia Citrodora Essential Oil Inhibits Melanoma Cell Growth and Migration by Targeting HB-EGF-EGFR Signaling

Patients diagnosed with melanoma have a poor prognosis due to regional invasion and metastases. The receptor tyrosine kinase epidermal growth factor receptor (EGFR) is found in a subtype of melanoma with a poor prognosis and contributes to drug resistance. Aloysia citrodora essential oil (ALOC-EO) possesses an antitumor effect. Understanding signaling pathways that contribute to the antitumor of ALOC-EO is important to identify novel tumor types that can be targeted by ALOC-EO. Here, we investigated the effects of ALOC-EO on melanoma growth and tumor cell migration. ALOC-EO blocked melanoma growth in vitro and impaired primary tumor cell growth in vivo. Mechanistically, ALOC-EO blocked heparin-binding-epidermal growth factor (HB-EGF)-induced EGFR signaling and suppressed ERK1/2 phosphorylation. Myelosuppressive drugs upregulated HB-EGF and EGFR expression in melanoma cells. Cotreatment of myelosuppressive drugs with ALOC-EO improved the antitumor activity and inhibited the expression of matrix metalloproteinase-7 and -9 and a disintegrin and metalloproteinase domain-containing protein9. In summary, our study demonstrates that ALOC-EO blocks EGFR and ERK1/2 signaling, with preclinical efficacy as a monotherapy or in combination with myelosuppressive drugs in melanoma.

The physiological role of Homer2a and its novel short isoform, Homer2e, in NMDA receptor-mediated apoptosis in cerebellar granule cells

Homer is a postsynaptic scaffold protein, which has long and short isoforms. The long form of Homer consists of an N-terminal target-binding domain and a C-terminal multimerization domain, linking multiple proteins within a complex. The short form of Homer only has the N-terminal domain and likely acts as a dominant negative regulator. Homer2a, one of the long form isoforms of the Homer family, expresses with a transient peak in the early postnatal stage of mouse cerebellar granule cells (CGCs); however, the functions of Homer2a in CGCs are not fully understood yet. In this study, we investigated the physiological roles of Homer2a in CGCs using recombinant adenovirus vectors. Overexpression of the Homer2a N-terminal domain construct, which was made structurally reminiscent with Homer1a, altered NMDAR1 localization, decreased NMDA currents, and promoted the survival of CGCs. These results suggest that the Homer2a N-terminal domain acts as a dominant negative protein to attenuate NMDAR-mediated excitotoxicity. Moreover, we identified a novel short form N-terminal domain-containing Homer2, named Homer2e, which was induced by apoptotic stimulation such as ischemic brain injury. Our study suggests that the long and short forms of Homer2 are involved in apoptosis of CGCs.

Suppression of lysosomal acid alpha-glucosidase impacts the modulation of transcription factor EB translocation in pancreatic cancer

Lysosomal degradation plays a crucial role in the metabolism of biological macromolecules supplied by autophagy. The regulation of the autophagy‐lysosome system, which contributes to intracellular homeostasis, chemoresistance, and tumor progression, has recently been revealed as a promising therapeutic approach for pancreatic cancer (PC). However, the details of lysosomal catabolic function in PC cells have not been fully elucidated. In this study, we show evidence that suppression of acid alpha‐glucosidase (GAA), one of the lysosomal enzymes, improves chemosensitivity and exerts apoptotic effects on PC cells through the disturbance of expression of the transcription factor EB. The levels of lysosomal enzyme were elevated by gemcitabine in PC cells. In particular, the levels of GAA were responsive to gemcitabine in a dose–dependent and time–dependent manner. Small interfering RNA against the GAA gene (siGAA) suppressed cell proliferation and promoted apoptosis in gemcitabine‐treated PC cells. In untreated PC cells, we observed accumulation of depolarized mitochondria. Gene therapy using adenoviral vectors carrying shRNA against the GAA gene increased the number of apoptotic cells and decreased the tumor growth in xenograft model mice. These results indicate that GAA is one of the key targets to improve the efficacy of gemcitabine and develop novel therapies for PC.

Construction of adenovirus vectors simultaneously expressing four multiplex, double-nicking guide RNAs of CRISPR/Cas9 and in vivo genome editing

Simultaneous expression of multiplex guide RNAs (gRNAs) is valuable for knockout of multiple genes and also for effective disruption of a gene by introducing multiple deletions. We developed a method of Tetraplex-guide Tandem for construction of cosmids containing four and eight multiplex gRNA-expressing units in one step utilizing lambda in vitro packaging. Using this method, we produced an adenovirus vector (AdV) containing four multiplex-gRNA units for two double-nicking sets. Unexpectedly, the AdV could stably be amplified to the scale sufficient for animal experiments with no detectable lack of the multiplex units. When the AdV containing gRNAs targeting the H2-Aa gene and an AdV expressing Cas9 nickase were mixed and doubly infected to mouse embryonic fibroblast cells, deletions were observed in more than 80% of the target gene even using double-nicking strategy. Indels were also detected in about 20% of the target gene at two sites in newborn mouse liver cells by intravenous injection. Interestingly, when one double-nicking site was disrupted, the other was simultaneously disrupted, implying that two genes in the same cell may simultaneously be disrupted in the AdV system. The AdVs expressing four multiplex gRNAs could offer simultaneous knockout of four genes or two genes by double-nicking cleavages with low off-target effect.

Development of indirect ELISA for the detection of canine adenovirus type 2 antibodies in dog sera

Background

Canine adenovirus type 2 (CAV-2) induces infectious laryngotracheitis in members of the family Canidae, including dogs. To date, no ELISA kits specific for CAV-2 antibody have been commercialized for dogs in Korea.

Objectives

We aimed to develop new indirect enzyme-linked immunosorbent assay (I-ELISA) to perform rapid, accurate serological surveys of CAV-2 in dog serum samples.

Methods

In total, 165 serum samples were collected from dogs residing in Chungbuk and Gyeongbuk provinces between 2016 and 2018. The Korean CAV-2, named the APQA1701-40P strain, was propagated in Madin–Darby canine kidney cells and purified in an anion-exchange chromatography column for use as an antigen for I-ELISA. The virus-neutralizing antibody titers of CAV-2 in the dog sera were measured by virus neutralization (VN) test.

Results

We compared the results obtained between the VN and new I-ELISA tests. The sensitivity, specificity, and accuracy of new I-ELISA were 98.6%, 86.4% and 97.0% compared with VN test, respectively. New I-ELISA was significantly correlated with VN (r = 0.91).

Conclusions

These results indicate that new I-ELISA is useful for sero-surveillance of CAV-2 in dog serum.

Combination of rAd-p53 in situ gene therapy and anti-PD-1 antibody immunotherapy induced anti-tumor activity in mouse syngeneic urogenital cancer models

In this study we undertook a novel combination therapy using rAd-p53 in situ gene therapy and immunotherapy with immune checkpoint inhibitor (ICI) anti-PD-1 antibody for urogenital cancers. Three mouse syngeneic tumor cell lines, TRAMP-C2 (prostate cancer derived from C57BL/6 mice), MBT-2 (bladder cancer derived from C3H mice) and Renca (kidney cancer derived from BALB/c mice) were used in this study. The highest coxsackie and adenovirus receptor (CAR) mRNA expression was observed in TRAMP-C2 cells, followed by Renca and then MBT-2 cells. Consistent with the CAR expressions, rAd-p53 at 160 multiplicity of infection (MOI) significantly inhibited the cell proliferation of TRAMP-C2 and Renca cells, but not MBT-2 cells. In in vivo experiments, the combination of intratumoral injections of rAd-p53 (1 × 10⁹ plaque-forming units) every other day and intraperitoneal injections of anti-mouse PD-1 antibody (200 μg) twice a week suppressed tumor growth and prolonged survival compared to rAd-p53 or anti-PD-1 antibody monotherapy in both the TRAMP-C2 and Renca models. Our results encourage the clinical development of combination therapy comprised of in situ gene therapy with rAd-p53 and immunotherapy with an ICI anti-PD-1 antibody for urogenital cancers.

Adenovirus 7 Induces Interlukin-6 Expression in Human Airway Epithelial Cells via p38/NF-κB Signaling Pathway

Human Adenovirus (AdV) infection is very common and usually has a significant impact on children. AdV-induced inflammation is believed to be one of the main causes of severe symptoms. However, an inflammatory response profile in the airway in AdV-infected children is still lacking, and the mechanism underlying AdV-induced inflammation in the airway is also poorly understood. In the current study, we determined the expression of a panel of inflammation cytokines in the airway samples from AdV 7 infected children and further investigated the molecular mechanism underlying AdV 7-induced cytokine expression. Our results showed that eight out of 13 tested inflammatory cytokines were significantly increased in nasal washes of AdV 7-infected children comparing to healthy control, with IL-6 showing the highest enhancement. AdV 7 infection of bronchial epithelial cell line and primary airway epithelial cells confirmed that AdV 7 increased IL-6 mRNA and protein expression in an infection dose-dependent manner. Promoter analysis revealed that AdV 7 infection transactivated IL-6 promoter and a NF-κB binding site in IL-6 promoter was involved in the transactivation. Further analysis showed that upon AdV 7 infection, NF-κB p65 was phosphorylated and translocated into nucleus and bound onto IL-6 promoter. Signaling pathway analysis revealed that p38/NF-κB pathway was involved in AdV 7 infection induced IL-6 elevation. Taken together, our study shows that AdV 7 infection triggers the expression of a range of inflammatory cytokines including IL-6 in the airway of infected children, and AdV 7 enhances IL-6 expression by transactivating IL-6 promoter via p38/NF-κB signaling pathway. Findings of our current study have provided more information toward a better understanding of AdV-induced airway inflammation, which might also benefit the development of intervention strategies.

Inhibitory Effect of PIK-24 on Respiratory Syncytial Virus Entry by Blocking Phosphatidylinositol-3 Kinase Signaling

Phosphoinositide-3 kinase signaling modulates many cellular processes, including cell survival, proliferation, differentiation, and apoptosis. Currently, it is known that the establishment of respiratory syncytial virus infection requires phosphoinositide-3 kinase signaling. However, the regulatory pattern of phosphoinositide-3 kinase signaling or its corresponding molecular mechanism during respiratory syncytial virus entry remains unclear. Here, the involvement of phosphoinositide-3 kinase signaling in respiratory syncytial virus entry was studied. PIK-24, a novel compound designed with phosphoinositide-3 kinase as a target, had potent anti-respiratory syncytial virus activity both in vitro and in vivo PIK-24 significantly reduced viral entry into the host cell through blocking the late stage of the fusion process. In a mouse model, PIK-24 effectively reduced the viral load and alleviated inflammation in lung tissue. Subsequent studies on the antiviral mechanism of PIK-24 revealed that viral entry was accompanied by phosphoinositide-3 kinase signaling activation, downstream RhoA and cofilin upregulation, and actin cytoskeleton rearrangement. PIK-24 treatment significantly reversed all these effects. The disruption of actin cytoskeleton dynamics or the modulation of phosphoinositide-3 kinase activity by knockdown also affected viral entry efficacy. Altogether, it is reasonable to conclude that the antiviral activity of PIK-24 depends on the phosphoinositide-3 kinase signaling and that the use of phosphoinositide-3 kinase signaling to regulate actin cytoskeleton rearrangement plays a key role in respiratory syncytial virus entry.

Oncolytic effect of Midkine promoter-based conditionally replicating adenoviruses expressing EGFR siRNA in head and neck squamous cancer cell line T891

Background

Epidermal growth factor receptor (EGFR) is overexpressed in head and neck squamous cell carcinomas (HNSCCs). Midkine expression is restricted in adult tissues but is increased in several malignant tumors, including HNSCCs.

Aim

Here, we evaluated the antitumor effect of Midkine promoter–based conditionally replicative adenovirus expressing siRNA against EGFR for targeting HNSCCs expressing Midkine.

Methods and results

A conditionally replicative adenovirus vector controlled by the Midkine promoter, Ad‐MK‐siEGFR, was generated by integrating gene‐expressing siRNA against EGFR. Antitumor effect of Ad‐MK‐siEGFR was tested in vitro using established HNSCC cell line, T891 with strong Midkine expression. Expression of EGFR in T891 infected with Ad‐MK‐siEGFR was significantly lower than that of T891 infected with control. Cytotoxicity assays showed significant growth suppression of Ad‐MK‐siEGFR in T891 cells.

Conclusions

This study demonstrated the possibility of oncolytic therapy using the Midkine promoter–based conditional replication‐selective adenovirus containing siRNA against EGFR in HNSCC cell line T891. Further validation of the findings in more cell lines and in vivo should be performed to clarify the potential clinical application.

The EGFL7-ITGB3-KLF2 axis enhances survival of multiple myeloma in preclinical models

Angiogenic factors play a key role in multiple myeloma (MM) growth, relapse, and drug resistance. Here we show that malignant plasma cells (cell lines and patient-derived MM cells) express angiocrine factor EGF like-7 (EGFL7) mRNA and protein. MM cells both produced EGFL7 and expressed the functional EGFL7 receptor integrin β 3 (ITGB3), resulting in ITGB3 phosphorylation and focal adhesion kinase activation. Overexpression of ITGB3 or EGFL7 enhanced MM cell adhesion and proliferation. Intriguingly, ITGB3 overexpression upregulated the transcription factor Krüppel-like factor 2 (KLF2), which further enhanced EGFL7 transcription in MM cells, thereby establishing an EGFL7-ITGB3-KLF2-EGFL7 amplification loop that supports MM cell survival and proliferation. EGFL7 expression was found in certain plasma cells of patients with refractory MM and of patients at primary diagnosis. NOD.CB17-Prkdc/J mice transplanted with MM cells showed elevated human plasma EGFL7 levels. EGFL7 knockdown in patient-derived MM cells and treatment with neutralizing antibodies against EGFL7 inhibited MM cell growth in vitro and in vivo. We demonstrate that the standard-of-care MM drug bortezomib upregulates EGFL7, ITGB3, and KLF2 expression in MM cells. Inhibition of EGFL7 signaling in synergy with BTZ may provide a novel strategy for inhibiting MM cell proliferation.

Current challenges in biotherapeutic particles manufacturing

Introduction: The development of novel complex biotherapeutics led to new challenges in biopharmaceutical industry. The potential of these particles has been demonstrated by the approval of several products, in the different fields of gene therapy, oncolytic therapy, and tumor vaccines. However, their manufacturing still presents challenges related to the high dosages and purity required.Areas covered: The main challenges that biopharmaceutical industry faces today and the most recent developments in the manufacturing of different biotherapeutic particles are reported here. Several unit operations and downstream trains to purify virus, virus-like particles and extracellular vesicles are described. Innovations on the different purification steps are also highlighted with an eye on the implementation of continuous and integrated processes.Expert opinion: Manufacturing platforms that consist of a low number of unit operations, with higher-yielding processes and reduced costs will be highly appreciated by the industry. The pipeline of complex therapeutic particles is expanding and there is a clear need for advanced tools and manufacturing capacity. The use of single-use technologies, as well as continuous integrated operations, are gaining ground in the biopharmaceutical industry and should be supported by more accurate and faster analytical methods.

Human adenovirus type 7 infection causes a more severe disease than type 3

Background

Human adenovirus type 3 (HAdV-3) and 7 (HAdV-7) cause significant morbidity and develop severe complications and long-term pulmonary sequelae in children. However, epidemiologic reports have suggested that nearly all highly severe or fatal adenoviral diseases in children are associated with HAdV-7 rather than HAdV-3. Here, we conduct in-depth investigations to confirm and extend these findings through a comprehensive series of assays in vitro and in vivo as well as clinical correlates.

Methods

A total of 8248 nasopharyngeal aspirate (NPA) samples were collected from hospitalized children with acute respiratory infections in Children’s Hospital of Chongqing Medical University from June 2009 to May 2015. Among 289 samples that tested positive for HAdVs, clinical data of 258 cases of HAdV-3 (127) and HAdV-7 (131) infections were analyzed. All HAdV-positive samples were classified by sequencing the hexon and fiber genes, and compared with clinical data and virological assays. We also performed in vitro assays of virus quantification, viral growth kinetics, competitive fitness, cytotoxicity and C3a assay of the two strains. Mouse adenovirus model was used to evaluate acute inflammatory responses.

Results

Clinical characteristics revealed that HAdV-7 infection caused more severe pneumonia, toxic encephalopathy, respiratory failure, longer mean hospitalization, significantly lower white blood cell (WBC) and platelet counts, compared to those of HAdV-3. In cell culture, HAdV-7 replicated at a higher level than HAdV-3, and viral fitness showed significant differences as well. HAdV-7 also exhibited higher C3a production and cytotoxic effects, and HAdV-7-infected mice showed aggravated pathology and higher pulmonary virus loads, compared to HAdV-3-infected mice. Macrophages in BALF remained markedly high during infection, with concomitant increase in pro-inflammatory cytokines (TNF-α, IL-1β, IFN-γ, and IL-6), compared HAdV-3 infection.

Conclusions

These results document that HAdV-7 replicates more robustly than HAdV-3, and promotes an exacerbated cytokine response, causing a more severe airway inflammation. The findings merit further mechanistic studies that offer the pediatricians an informed decision to proceed with early diagnosis and treatment of HAdV-7 infection.

Overexpression of SOCS3 mediated by adenovirus vector in mouse and human castration-resistant prostate cancer cells increases the sensitivity to NK cells in vitro and in vivo

Prostate cancer is one of the most common cancers in men. The overactivation of IL-6/JAK/STAT3 signaling and silencing of SOCS3 are frequently observed in prostate cancer. In the present study we undertook to develop Ad-SOCS3 gene therapy for the treatment of prostate cancer and also investigated whether Ad-SOCS3 increased sensitivity to NK cells. We demonstrated that Ad-SOCS3 could significantly inhibit growth of castration-resistant prostate cancer (CRPC) cell lines expressing pSTAT3, DU-145 (at 10, 20, and 40 MOI), and TRAMP-C2 (at 40 MOI), but not the PC-3 CRPC cell line with the STAT3 gene deleted. Ad-SOCS3 (40 MOI) could suppress IL-6 production in DU-145 cells and PD-L1 expression induced by IFN-γ in TRAMP-C2 cells, and increased the NK cell sensitivity of both TRAMP-C2 and DU-145 cells. In the DU-145 mouse xenograft tumor model, intratumoral injections (twice/week for 3 weeks) of 1 × 10⁸ pfu of Ad-SOCS3 significantly inhibited tumor growth and combining the Ad-SOCS3 treatment with intratumoral injections (once/week for 2 weeks) of 1 × 10⁷ human NK cells showed the highest tumor growth inhibitory effect. These results suggested that a combination of Ad-SOCS3 gene therapy and NK cell immunotherapy could be a powerful treatment option for advanced CRPC overexpressing pSTAT3.

The fibrinolytic factor tPA drives LRP1-mediated melanoma growth and metastasis

The multifunctional endocytic receptor low-density lipoprotein receptor-related protein (LRP)1 has recently been identified as a hub within a biomarker network for multicancer clinical outcome prediction. The mechanism how LRP1 modulates cancer progression is poorly understood. In this study we found that LRP1 and one of its ligands, tissue plasminogen activator (tPA), are expressed in melanoma cells and control melanoma growth and lung metastasis in vivo. Mechanistic studies were performed on 2 melanoma cancer cell lines, B16F10 and the B16F1 cells, both of which form primary melanoma tumors, but only B16F10 cells metastasize to the lungs. Tumor-, but not niche cell-derived tPA, enhanced melanoma cell proliferation in tPA^-/- mice. Gain-of-function experiments revealed that melanoma LRP1 is critical for tumor growth, recruitment of mesenchymal stem cells into the tumor bed, and metastasis. Melanoma LRP1 was found to enhance ERK activation, resulting in increased matrix metalloproteinase (MMP)-9 RNA, protein, and secreted activity, a well-known modulator of melanoma metastasis. Restoration of LRP1 and tPA in the less aggressive, poorly metastatic B16F1 tumor cells enhanced tumor cell proliferation and led to massive lung metastasis in murine tumor models. Antimelanoma drug treatment induced tPA and LRP1 expression. tPA or LRP1 knockdown enhanced chemosensitivity in melanoma cells. Our results identify the tPA-LRP1 pathway as a key switch that drives melanoma progression, in part by modulating the cellular composition and proteolytic makeup of the tumor niche. Targeting this pathway may be a novel treatment strategy in combination treatments for melanoma.-Salama, Y., Lin, S.-Y., Dhahri, D., Hattori, K., Heissig, B. The fibrinolytic factor tPA drives LRP1-mediated melanoma growth and metastasis.

A Flow Cytometry-Based Method to Determine the Titer of Adenoviruses Expressing an Extraneous Gene

In recent times, oncolytic viruses expressing an extraneous gene have attracted great interest; in fact, they have been engaged in multiple applications, such as medicine for cancer. Our group made an oncolytic adenovirus, namely, OBP-301, for use in treating solid cancers and press clinical trial to get approval for a pharmaceutical product. In this study, we applied a flow cytometry-based method to determine the titer of adenoviruses expressing an extraneous gene as well as assess their quality. We considered using the green fluorescent protein (GFP)₅₀ titer as a measure of viral quality. The GFP₅₀ titer (GFP₅₀/mL) is the viral load required to render the HeLa S3 cell line 50% GFP-positive by analysing flow cytometry data. We measured the GFP₅₀ titers for three types of recombinant adenoviruses (OBP-401, OBP-1101, and OBP-1106). We compared GFP₅₀/mL and tissue culture infectious dose (TCID₅₀/mL), a conventional titration index, and found that these titers showed a linear correlation, with a correlation coefficient of >0.9. Moreover, GFP₅₀/mL showed high repetitive accuracy. We expect this flow cytometry-based method to be useful in case of clinically relevant viruses expressing an extraneous gene, in particular, to control viral quality.

Replication-incompetent rabies virus vector harboring glycoprotein gene of lymphocytic choriomeningitis virus (LCMV) protects mice from LCMV challenge

BACKGROUND

Lymphocytic choriomeningitis virus (LCMV) causes a variety of diseases, including asymptomatic infections, meningitis, and congenital infections in the fetus of infected mother. The development of a safe and effective vaccine against LCMV is imperative. This study aims to develop a new candidate vaccine against LCMV using a recombinant replication-incompetent rabies virus (RV) vector.

METHODOLOGY/PRINCIPAL FINDINGS

In this study, we have generated a recombinant deficient RV expressing the LCMV glycoprotein precursor (GPC) (RVΔP-LCMV/GPC) which is lacking the RV-P gene. RVΔP-LCMV/GPC is able to propagate only in cells expressing the RV-P protein. In contrast, the LCMV-GPC can be expressed in general cells, which do not express RV-P protein. The ability of RVΔP-LCMV/GPC to protect mice from LCMV infection and induce cellular immunity was assessed. Mice inoculated intraperitoneally with RVΔP-LCMV/GPC showed higher survival rates (88.2%) than those inoculated with the parental recombinant RV-P gene-deficient RV (RVΔP) (7.7%) following a LCMV challenge. Neutralizing antibody (NAb) against LCMV was not induced, even in the sera of surviving mice. CD8+ T-cell depletion significantly reduced the survival rates of RVΔP-LCMV/GPC-inoculated mice after the LCMV challenge. These results suggest that CD8+ T cells play a major role in the observed protection against LCMV. In contrast, NAbs against RV were strongly induced in sera of mice inoculated with either RVΔP-LCMV/GPC or RVΔP. In safety tests, suckling mice inoculated intracerebrally with RVΔP-LCMV/GPC showed no symptoms.

CONCLUSIONS/SIGNIFICANCE

These results show RVΔP-LCMV/GPC might be a promising candidate vaccine with dual efficacy, protecting against both RV and LCMV.

Hdac7 promotes lung tumorigenesis by inhibiting Stat3 activation

Background

Lung cancer is the leading cause of cancer death worldwide. However, the molecular mechanisms underlying lung cancer development have not been fully understood. The functions of histone deacetylases (HDACs), a class of total eighteen proteins (HDAC1–11 and SIRT1–7 in mammals) that deacetylate histones and non-histone proteins, in cancers are largely unknown.

Methods

Hdac7^+/−/K-Ras mice and HDAC7-depleted human lung cancer cell lines were used as models for studying the function of Hdac7 gene in lung cancer. Kaplan-Meier survival analysis was performed to explore the relationship between HDAC7 expression and prognosis of human lung cancers. Recombinant lentivirus-mediated in vivo gene expression or knockdown, Western blotting, and pull-down assay were applied to investigate the underlying molecular mechanism by which Hdac7 promotes lung tumorigenesis.

Results

The number and burden of lung tumor were dramatically reduced in Hdac7^+/−/K-Ras mice compared to control K-Ras mice. Also, in Hdac7^+/−/K-Ras mice, cell proliferation was significantly inhibited and apoptosis in lung tumors was greatly enhanced. Similarly, cell proliferation and anchorage-independent growth of human lung cancer cell lines expressing shHDAC7 were also significantly suppressed and apoptosis was dramatically elevated respectively. Mechanistic study revealed that Hdac7 mutation in mouse lung tumors or HDAC7 depletion in human tumor cell lines resulted in significantly enhanced acetylation and tyrosine-phosphorylation of Stat3 and HDAC7 protein directly interacted with and deacetylateed STAT3. The Hdac7 mutant-mediated inhibitory effects on lung tumorigenesis in mice and cell proliferation/soft agar colony formation of human lung cancer cell lines were respectively reversed by expressing dnStat3. Finally, the high HDAC7 mRNA level was found to be correlated with poor prognosis of human lung cancer patients.

Conclusion

Our study suggests that Hdac7 promotes lung tumorigenesis by inhibiting Stat3 activation via deacetylating Stat3 and may shed a light on the design of new therapeutic strategies for human lung cancer.

Electronic supplementary material

The online version of this article (10.1186/s12943-017-0736-2) contains supplementary material, which is available to authorized users.

Adenovirus vector expressing keratinocyte growth factor using CAG promoter impairs pulmonary function of mice with elastase-induced emphysema

Pulmonary emphysema impairs quality of life and increases mortality. It has previously been shown that administration of adenovirus vector expressing murine keratinocyte growth factor (KGF) before elastase instillation prevents pulmonary emphysema in mice. We therefore hypothesized that therapeutic administration of KGF would restore damage to lungs caused by elastase instillation and thus improve pulmonary function in an animal model. KGF expressing adenovirus vector, which prevented bleomycin-induced pulmonary fibrosis in a previous study, was constructed. Adenovirus vector (1.0 × 10⁹ plaque-forming units) was administered intratracheally one week after administration of elastase into mouse lungs. One week after administration of KGF-vector, exercise tolerance testing and blood gas analysis were performed, after which the lungs were removed under deep anesthesia. KGF-positive pneumocytes were more numerous, surfactant protein secretion in the airspace greater and mean linear intercept of lungs shorter in animals that had received KGF than in control animals. Unexpectedly, however, arterial blood oxygenation was worse in the KGF group and maximum running speed, an indicator of exercise capacity, had not improved after KGF in mice with elastase-induced emphysema, indicating that KGF-expressing adenovirus vector impaired pulmonary function in these mice. Notably, vector lacking KGF-expression unit did not induce such impairment, implying that the KGF expression unit itself may cause the damage to alveolar cells. Possible involvement of the CAG promoter used for KGF expression in impairing pulmonary function is discussed.

Comparison of protein expression during wild-type, and E1B-55k-deletion, adenovirus infection using quantitative time-course proteomics

Adenovirus has evolved strategies to usurp host-cell factors and machinery to facilitate its life cycle, including cell entry, replication, assembly and egress. Adenovirus continues, therefore, to be an important model system for investigating fundamental cellular processes. The role of adenovirus E1B-55k in targeting host-cell proteins that possess antiviral activity for proteasomal degradation is now well established. To expand our understanding of E1B-55k in regulating the levels of host-cell proteins, we performed comparative proteome analysis of wild-type, and E1B-55k-deletion, adenovirus-infected cancer cells. As such we performed quantitative MS/MS analysis to monitor protein expression changes affected by viral E1B-55k. We identified 5937 proteins, and of these, 69 and 58 proteins were down-regulated during wild-type and E1B-55k (dl1520) adenovirus infection, respectively. This analysis revealed that there are many, previously unidentified, cellular proteins subjected to degradation by adenovirus utilizing pathways independent of E1B-55k expression. Moreover, we found that ALCAM, EPHA2 and PTPRF, three cellular proteins that function in the regulation of cell-cell contacts, appeared to be degraded by E1B-55k/E4orf3 and/or E1B-55k/E4orf6 complexes. These molecules, like integrin α3 (a known substrate of E1B-55k/E4orf6), are critical regulators of cell signalling, cell adhesion and cell surface modulation, and their degradation during infection is, potentially, pertinent to adenovirus propagation. The data presented in this study illustrate the broad nature of protein down-regulation mediated by adenovirus.

Combination of p53-DC vaccine and rAd-p53 gene therapy induced CTLs cytotoxic against p53-deleted human prostate cancer cells in vitro

Recently, the US FDA approved sipuleucel-T, which is composed of autologous DCs stimulated with a recombinant fusion protein of prostatic acid phosphatase (PAP) and granulocyte-macrophage colony-stimulating factor (GM-CSF), as the first immunotherapeutic agent for metastatic castration resistant prostate cancer (mCRPC). However, sipuleucel-T demonstrated only modest efficacy in mCPRC patients. Researchers are now investigating the potential of p53 protein as a tumor-associated antigen (TAA) loaded in DC-based cancer vaccine. Approximately half of all tumors overexpress p53, and up to 20% of prostate cancer cells overexpresses p53. In this study, we evaluated the feasibility of combining p53-DC vaccine and rAd-p53 gene therapy, using the p53-overexpressing and non-expressing prostate cancer cells in vitro. We successfully generated the p53-DC vaccine by culturing autologous DCs infected with rAd-p53. This p53-DC vaccine can differentiate CTLs specifically cytotoxic to p53-overexpressing prostate cancer cells. In addition, rAd-p53 infection can induce overexpression of p53 and thus the cytotoxicity of CTLs differentiated by the p53-DC vaccine in p53 non-expressing prostate cancer cells. These findings suggest that this combination therapy using p53-DC vaccine and rAd-p53 gene therapy together may represent a new paradigm for the treatment of mCRPC.

Development of a prototype immunochromatographic test for rapid diagnosis of respiratory adenovirus infection

Human adenoviruses comprise an important group of etiologic agents that are responsible for various diseases in adults and children, such as respiratory, ocular, gastroenteric, and urinary infections. In immunocompromised and organ-transplanted individuals, these agents can cause generalized infections. Rapid diagnostic methods for detecting these infectious agents are not widely available.

The aim of this work was to produce monoclonal and polyclonal anti-adenovirus antibodies to be used in a rapid diagnostic test for respiratory infections.

Adenovirus hexons were satisfactorily purified by ultracentrifugation and chromatography. After virus purification, anti-hexon monoclonal antibodies were produced and characterized, following classical methods. Antibodies were specific for adenoviruses 2, 3, 5, and 41. The proposed immunochromatographic test was standardized using colloidal gold.

The standardization of the rapid test was sufficient to detect adenovirus antigens (in nasopharyngeal lavage samples) with sensitivity of 100% and specificity of 85% when compared to direct immunofluorescence.

The immunochromatographic assay prototype was sufficiently sensitive to detect B (3), C (2 and 5), and F (41) adenovirus samples. Although based on preliminary data, the test demonstrated the same performance as direct immunofluorescence, but with the advantage of being a point-of-care test. Further studies are still needed to confirm its effectiveness in clinical practice.

The angiogenic factor Egfl7 alters thymogenesis by activating Flt3 signaling

Thymic regeneration is a crucial function that allows for the generation of mature T cells after myelosuppression like irradiation. However molecular drivers involved in this process remain undefined. Here, we report that the angiogenic factor, epidermal growth factor-like domain 7 (Egfl7), is expressed on steady state thymic endothelial cells (ECs) and further upregulated under stress like post-irradiation. Egfl7 overexpression increased intrathymic early thymic precursors (ETPs) and expanded thymic ECs. Mechanistically, we show that Egfl7 overexpression caused Flt3 upregulation in ETPs and thymic ECs, and increased Flt3 ligand plasma elevation in vivo. Selective Flt3 blockade prevented Egfl7-driven ETP expansion, and Egfl7-mediated thymic EC expansion in vivo. We propose that the angiogenic factor Egfl7 activates the Flt3/Flt3 ligand pathway and is a key molecular driver enforcing thymus progenitor generation and thereby directly linking endothelial cell biology to the production of T cell-based adaptive immunity.

Efficient genome replication of hepatitis B virus using adenovirus vector: a compact pregenomic RNA-expression unit

The complicated replication mechanisms of hepatitis B virus (HBV) have impeded HBV studies and anti-HBV therapy development as well. Herein we report efficient genome replication of HBV applying adenovirus vectors (AdVs) showing high transduction efficiency. Even in primary hepatocytes derived from humanized mice the transduction efficiencies using AdVs were 450-fold higher compared than those using plasmids. By using an expression unit consisting of the CMV promoter, 1.03-copy HBV genome and foreign poly(A) signal, we successfully generated an improved AdV (HBV103-AdV) that efficiently provided 58 times more pregenomic RNA than previously reported AdVs. The HBV103-AdV-mediated HBV replication was easily and precisely detected using quantitative real-time PCR in primary hepatocytes as well as in HepG2 cells. Notably, when the AdV containing replication-defective HBV genome of 1.14 copy was transduced, we observed that HBV DNA-containing circular molecules (pseudo-ccc DNA) were produced, which were probably generated through homologous recombination. However, the replication-defective HBV103-AdV hardly yielded the pseudo-ccc, probably because the repeated sequences are vey short. Additionally, the efficacies of entecavir and lamivudine were quantitatively evaluated using this system at only 4 days postinfection with HBV103-AdVs. Therefore, this system offers high production of HBV genome replication and thus could become used widely.

Adenovirus-mediated truncated Bid overexpression induced by the Cre/LoxP system promotes the cell apoptosis of CD133+ ovarian cancer stem cells

Cancer stem cells are a small subset of cancer cells that contribute to cancer progression, metastasis, chemoresistance and recurrence. CD133-positive (CD133+) ovarian cancer cells have been identified as ovarian cancer stem cells. Adenovirus-mediated gene therapy is an innovative therapeutic method for cancer treatment. In the present study, we aimed to develop a new gene therapy to specifically eliminate CD133+ ovarian cancer stem cells by targeting CD133. We used the Cre/LoxP system to augment the selective expression of the truncated Bid (tBid) gene as suicide gene therapy in CD133+ ovarian cancer stem cells. The adenovirus (Ad)-CD133-Cre expressing Cre recombinase under the control of the CD133 promoter and Ad-CMV-LoxP-Neo-LoxP-tBid expressing tBid under the control of the CMV promoter were successfully constructed using the Cre/LoxP switching system. The co-infection of Ad-CMV-LoxP-Neo-LoxP-tBid and Ad-CD133-Cre selectively induced tBid overexpression, which inhibited cell growth and triggered the cell apoptosis of CD133+ ovarian cancer stem cells. The Cre/LoxP system-mediated tBid overexpression activated the pro-apoptotic signaling pathway and augmented the cytotoxic effect of cisplatin in CD133+ ovarian cancer stem cells. Furthermore, in xenograft experiments, co-infection with the two recombinant adenoviruses markedly suppressed tumor growth in vivo and promoted cell apoptosis in tumor tissues. Taken together, the present study provides evidence that the adenovirus-mediated tBid overexpression induced by the Cre/LoxP system can effectively eliminate CD133+ ovarian cancer stem cells, representing a novel therapeutic strategy for the treatment of ovarian cancer.

Functional validation and expression analysis of myotubes converted from skin fibroblasts using a simple direct reprogramming strategy

Previously, we reported that MyoD, a master gene for myogenic cells, could efficiently convert primary skin fibroblasts into myoblasts and myotubes, thereby effecting direct reprogramming. In this study, we further demonstrated that MyoD-expressing primary fibroblasts displayed rapid movement in culture, with a movement velocity that was significantly faster, almost four times, than mouse primary myoblasts. MyoD-transduced cells obtained the characteristics of Ca^2 + release and electrically-stimulated contraction, which was comparable to C2C12 myotubes, suggesting that the essential features of muscle were observed in the transduced cells. Furthermore, the ability to fuse to the host myoblasts means that gene transfer from MyoD-transduced cells to host muscle cells could be obtained by cell fusion. In comparison with the iPS method (indirect reprogramming), our transduction method has a low risk for tumorigenesis and carcinogenesis because the starting cells are fibroblasts and the transduced cells are myoblasts, both normal and mortal cells. Accordingly, MyoD transduction of human skin fibroblasts using the adenoviral vector is a simple, inexpensive and promising candidate as a new cell transplantation therapy for patients with muscular disorders.

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Adenoviral MyoD vector transduced fibroblasts directly to myoblasts.

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Myoblast cells were well differentiated into functional muscle cells.

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Direct reprogramming is cost-effective and safe compared to iPS method.

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Cell fusion and high motility were observed in MyoD-transduced cells.

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Transduced cells are candidates for cell transplantation in muscle disorders.

Truncated Bid Overexpression Induced by Recombinant Adenovirus Cre/LoxP System Suppresses the Tumorigenic Potential of CD133+ Ovarian Cancer Stem Cells

Ovarian cancer is one of the most lethal malignant gynecologic tumors with a high relapse rate worldwide. Cancer stem cells (CSCs) have been identified in ovarian cancer and other malignant tumors as a small population of cells that are capable of self-renewal and multidifferentiation. CD133⁺ ovarian CSCs have been reported to be more tumorigenic and more resistant to chemotherapeutic treatment. Thus, CD133 has emerged as one of the most promising therapeutic markers for ovarian cancer treatment. In the current study, we constructed a recombinant adenovirus Cre/loxP regulation system to selectively introduce truncated Bid (tBid) expression specifically targeting CD133⁺ in ovarian CSCs. The results demonstrated that the coinfection of Ad-CD133-Cre and Ad-CMV-LoxP-Neo-LoxP-tBid significantly increased tBid expression in CD133⁺ ovarian CSCs. Moreover, the tBid overexpression induced by a recombinant adenovirus Cre/loxP system dramatically inhibited cell proliferation and invasion, significantly elevated cell apoptosis, and activated the mitochondrial apoptosis pathway in CD133⁺ ovarian CSCs. Additionally, recombinant adenovirus Cre/loxP system-mediated tBid overexpression suppressed the tumorigenic potential of CD133⁺ ovarian CSCs in a xenograft mouse model. In conclusion, our study successfully constructed a recombinant adenovirus Cre/loxP system and induced tBid overexpression in CD133⁺ ovarian CSCs, providing a new therapeutic approach for ovarian cancer treatment.

Expression of HIF-1α ODD domain fused canine caspase 3 by EGFR promoter-driven adenovirus vector induces cytotoxicity in canine breast tumor cells under hypoxia

Adenovirus (Ad) vectors are widely used in cancer gene therapies. However, compared to human patients, relatively limited information is available on gene transduction efficiency or cell-specific cytotoxicity in canine tumor cells transduced with Ad vectors. Since epidermal growth factor receptor (EGFR) is highly expressed on canine breast tumor cells, we sought to develop an Ad vector based on the RGD fiber-mutant adenovirus vector (AdRGD) that expresses canine caspase 3 under the control of EGFR promoter. The aims of this study were to achieve high transduction efficiency with transgene expression restricted to canine breast tumor cells. Using EGFR promoter-driven AdRGD, we were able to restrict transgene expression to canine breast tumor cells with no evidence of expression in normal cells. Canine breast tumor cells transduced with EGFR promoter-driven AdRGD carrying canine caspase 3 gene showed cytotoxic activity. We constructed a second AdRGD vector that expressed oxygen-dependent degradation (ODD)-caspase 3 under the control of the EGFR promoter; the fusion protein contains a core part of the ODD domain of hypoxia inducible factor-1 alpha (HIF-1α) fused to caspase 3. Transduction of canine breast tumor cells with EGFR promoter-driven AdRGD expressing ODD-caspase 3 induced a higher rate of cell death under hypoxic conditions compared with under normoxia. The results indicate that the EGFR promoter-driven AdRGD vectors will be of value for tumor-specific transgene expression and safe cancer gene therapy in dogs.

Viral Vector Production: Adenovirus

Adenoviral vectors have proven to be valuable resources in the development of novel therapies aimed at targeting pathological conditions of the central nervous system, including Alzheimer's disease and neoplastic brain lesions. Not only can some genetically engineered adenoviral vectors achieve remarkably efficient and specific gene delivery to target cells, but they also may act as anticancer agents by selectively replicating within cancer cells.Due to the great interest in using adenoviral vectors for various purposes, the need for a comprehensive protocol for viral vector production is especially apparent. Here, we describe the process of generating an adenoviral vector in its entirety, including the more complex process of adenoviral fiber modification to restrict viral tropism in order to achieve more efficient and specific gene delivery.

Pulmonary vasculature directed adenovirus increases epithelial lining fluid alpha-1 antitrypsin levels

BACKGROUND

Gene therapy for inherited serum deficiency disorders has previously been limited by the balance between obtaining adequate expression and causing hepatic toxicity. Our group has previously described modifications of a replication deficient human adenovirus serotype 5 that increase pulmonary vasculature transgene expression.

METHODS

In the present study, we use a modified pulmonary targeted adenovirus to express human alpha-1 antitrypsin (A1AT) in C57BL/6 J mice.

RESULTS

Using the targeted adenovirus, we were able to achieve similar increases in serum A1AT levels with less liver viral uptake. We also increased pulmonary epithelial lining fluid A1AT levels by more than an order of magnitude compared to that of untargeted adenovirus expressing A1AT in a mouse model. These gains are achieved along with evidence of decreased systemic inflammation and no evidence for increased inflammation within the vector-targeted end organ.

CONCLUSIONS

In addition to comprising a step towards clinically viable gene therapy for A1AT, maximization of protein production at the site of action represents a significant technical advancement in the field of systemically delivered pulmonary targeted gene therapy. It also provides an alternative to the previous limitations of hepatic viral transduction and associated toxicities.

Efficient Gene Transduction of Dispersed Islet Cells in Culture Using Fiber-Modified Adenoviral Vectors

To establish novel islet-based therapies, our group has recently developed technologies for creating functional neo-islet tissues in the subcutaneous space by transplanting monolithic sheets of dispersed islet cells (islet cell sheets). Improving cellular function and viability are the next important challenges for enhancing the therapeutic effects. This article describes the adenoviral vector-mediated gene transduction of dispersed islet cells under culture conditions. Purified pancreatic islets were obtained from Lewis rats and dissociated into single islet cells. Cells were plated onto laminin-5-coated temperature-responsive polymer poly(N-isopropylacrylamide)-immobilized plastic dishes. At 0 h, islet cells were infected for 1 h with either conventional type 5 adenoviral vector (Ad-CA-GFP) or fiber-modified adenoviral vector (AdK7-CA-GFP) harboring a polylysine (K7) peptide in the C terminus of the fiber knob. We investigated gene transduction efficiency at 48 h after infection and found that AdK7-CA-GFP yielded higher transduction efficiencies than Ad-CA-GFP at a multiplicity of infection (MOI) of 5 and 10. For AdK7-CA-GFP at MOI = 10, 84.4 ± 1.5% of islet cells were found to be genetically transduced without marked vector infection-related cellular damage as determined by viable cell number and lactate dehydrogenase (LDH) release assay. After AdK7-CA-GFP infection at MOI = 10, cells remained attached and expanded to nearly full confluency, showing that this adenoviral infection protocol is a feasible approach for creating islet cell sheets. We have shown that dispersed and cultured islet cells can be genetically modified efficiently using fiber-modified adenoviral vectors. Therefore, this gene therapy technique could be used for cellular modification or biological assessment of dispersed islet cells.

5-Aminoimidazole-4-carboxyamide-1-β-D-ribofranoside stimulates the rat enhancer of split- and hairy-related protein-2 gene via atypical protein kinase C lambda

The 5'-AMP-activated protein kinase (AMPK) functions as a cellular energy sensor. 5-Aminoimidazole-4-carboxyamide-1-β-D-ribofranoside (AICAR) is a chemical activator of AMPK. In the liver, AICAR suppresses expression of thephosphoenolpyruvate carboxykinase(PEPCK) gene. The rat enhancer of split- and hairy-related protein-2 (SHARP-2) is an insulin-inducible transcriptional repressor and its target is thePEPCKgene. In this study, we examined an issue of whether theSHARP-2gene expression is regulated by AICAR via the AMPK. AICAR increased the level of SHARP-2 mRNA in H4IIE cells. Whereas an AMPK inhibitor, compound-C, had no effects on the AICAR-induction, inhibitors for both phosphoinositide 3-kinase (PI 3-K) and protein kinase C (PKC) completely diminished the effects of AICAR. Western blot analyses showed that AICAR rapidly activated atypical PKC lambda (aPKCλ). In addition, when a dominant negative form of aPKCλ was expressed, the induction of SHARP-2 mRNA level by AICAR was inhibited. Calcium ion is not required for the activation of aPKCλ. A calcium ion-chelating reagent had no effects on the AICAR-induction. Furthermore, the AICAR-induction was inhibited by treatment with an RNA polymerase inhibitor or a protein synthesis inhibitor. Thus, we conclude that the AICAR-induction of theSHARP-2gene is mediated at transcription level by a PI 3-K/aPKCλ pathway.

Single-step concentration and purification of adenoviruses by coxsackievirus-adenovirus receptor-binding capture and elastin-like polypeptide-mediated precipitation

A single-step method for quick concentration and purification of adenoviruses (Ads) was established by combining coxsackievirus and adenovirus receptor (CAR)-binding capture with elastin-like polypeptide (ELP)-mediated precipitation. The soluble ELP-CAR fusion protein was expressed in vector-transformed E. coli and purified to high purity by two rounds of inverse transition cycling (ITC). After demonstration of the specific binding of fusion protein, a recombinant Ad (rAd), namely rAd/GFP, was pulled down from the culture medium and extract of rAd-transduced cells using ELP-CAR protein, with recovery of 76.2 % and 73.3 %, respectively. The rAd was eluted from the ELP-CAR protein and harvested by one round of ITC, with recoveries ranging from 30.6 % to 34.5 % (virus titration assay). Both ELP-CAR-bound and eluted rAds were able to transduce CAR-positive cells, but not CAR-negative cells (fluorescent microscopy). A further viral titration assay showed that the ELP-CAR-bound rAd/GFP had significantly lower transduction efficiency than the eluted rAd, and there was less of a decrease when tested in the presence of fetal bovine serum. In addition, rAd/GFP was efficiently recovered from the "spiked" PBS and tap water with recovery of ~74 % or ~60 %. This work demonstrates the usefulness of the ELP-CAR-binding capture method for concentration and/or purification of Ads in cellular and environmental samples.

Potent effect of adenoviral vector expressing short hairpin RNA targeting ribonucleotide reductase large subunit M1 on cell viability and chemotherapeutic sensitivity to gemcitabine in non-small cell lung cancer cells

BACKGROUND

Ribonucleotide reductase large subunit (RRM1) is the main enzyme responsible for synthesis of the deoxyribonucleotides used during DNA synthesis. It is also a cellular target for gemcitabine (GEM). Overexpression of RRM1 is reportedly associated with resistance to GEM and the poor prognosis for many types of malignant tumours. Aim of the present study is to establish gene therapy against RRM1-overexpressing tumours.

METHOD

An adenoviral vector that encoded a short hairpin siRNA targeting the RRM1 gene (Ad-shRRM1) was constructed. Two RRM1-overexpressing non-small cell lung cancer (NSCLC) lines, MAC10 and RERF-LC-MA, were used. Finally, a human tumour xenograft model in nude mice was prepared by subcutaneously implanting tumours derived from RERF-LC-MA cells.

RESULTS

Ad-shRRM1 effectively downregulated RRM1 mRNA and protein in both types of NSCLC cells and significantly reduced the percentage of viable cells as detected by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay (p<0.005). Caspase 3/7 analysis revealed that transfection with Ad-RRM1 increased the percentage of apoptotic cells in culture containing either type of RRM1-overexpressing cell (p<0.001). Treatment with Ad-shRRM1 exerted a potent antitumour effect against the RRM1-overexpressing RERF-LC-MA xenografts (p<0.05). Furthermore, Ad-shRRM1-mediated inhibition of RRM1 specifically increased sensitivity to gemcitabine of each type of RRM1-overexpressing tumour cell. Combination treatment with Ad-shRRM1 and GEM exerted significantly greater inhibition on cell proliferation than Ad-shRRM1 or GEM treatment alone.

CONCLUSION

RRM1 appeared to be a promising target for gene therapy, and Ad-shRRM1 had strong antitumour effects, specifically anti-proliferative and pro-apoptotic effects, against NSCLC cells that overexpressed RRM1. Combination therapy with Ad-shRRM1 and GEM may become a new treatment option for patients with NSCLC.

Deficiency of GDNF Receptor GFRα1 in Alzheimer's Neurons Results in Neuronal Death

We have recently developed aged cortical neuron cultures from autopsied human brains with Alzheimer's disease (AD). During the culturing process, we found that glutamatergic cortical neurons from the AD brain lacked a response to glial cell line-derived neurotrophic factor (GDNF), including no axonal regrowth, and were starting to undergo apoptosis. Here we showed that, in cortical neurons from age- and gender-matched cognitively normal control (NC) subjects (NC neurons), GDNF enhanced the expression of GDNF family receptor subtype α1 (GFRα1), but not the other three subtypes (GFRα2, GFRα3, and GFRα4), whereas GDNF failed to induce GFRα1 expression in cortical neurons from the AD brain (AD neurons). The exogenous introduction of GFRα1, but not of its binding partner α1-neural cell adhesion molecule, or RET into AD neurons restored the effect of GDNF on neuronal survival. Moreover, between NC and AD neurons, the AMPA receptor blocker CNQX and the NMDA receptor blocker AP-5 had opposite effects on the GFRα1 expression induced by GDNF. In NC neurons, the presence of glutamate receptors was necessary for GDNF-linked GFRα1 expression, while in AD neurons the absence of glutamate receptors was required for GFRα1 expression by GDNF stimulation. These results suggest that, in AD neurons, specific impairments of GFRα1, which may be linked to glutamatergic neurotransmission, shed light on developing potential therapeutic strategies for AD by upregulation of GFRα1 expression.

Using adenovirus armed short hairpin RNA targeting transforming growth factor β1 inhibits melanoma growth and metastasis in an ex vivo animal model

The transforming growth factor β (TGF-β) is the key molecule implicated in impaired immune function in human patients with malignant melanoma. TGF-β can promote tumor growth, invasion, and metastasis in advanced stages of melanoma. Blocking these tumor-promoting effects of TGF-β provides a potentially important therapeutic strategy for the treatment of melanoma. In this study, we used an adenovirus-based shRNA expression system and successfully constructed Ad/TGF-β1-RNA interference (RNAi) which mediated the RNAi for TGF-β1 gene silencing. We examined the effects of TGF-β1 protein knockdown by RNAi on the growth and metastasis of melanoma in C57BL/6 mice induced by the B16F0 cell line. The TGF-β1 hairpin oligonucleotide was cloned into adenoviral vector. The resulting recombinant adenoviruses infected murine melanoma cell line, B16F0, and designated as B16F0/TGF-β1-RNAi cells. The blank adenoviral vector also infected B16F0 cells and designed as B16F0/vector-control cells served as a control. TGF-β1 expression was reduced in B16F0/TGF-β1-RNAi cells compared with B16F0 cells and B16F0/vector-control cells. Three million wild-type B16F0 cells, B16F0/vector-control cells, and B16F0/TGF-β1-RNAi cells were injected subcutaneously into the right flanks of adult female syngeneic mice C57BL/6. The tumor sizes were 756.09 (65.35), 798.48 (78.77), and 203.55 (24.56) mm at the 14th day in the mice receiving B16F0 cells, B16F0/vector-control cells, and B16F0/TGFβ1-RNAi cells, respectively. The P value was less than 0.01 by 1-way analysis of variance. TGF-β1 knockdown in B16F0 cells enhanced the infiltration of CD4 and CD8 T cells in the tumor regions. C57BL/6 mice were evaluated for pulmonary metastasis after tail vein injection of 2 million B16F0 cells, B16F0/vector-control cells, and B16F0/TGF-β1-RNAi cells. The pulmonary metastasis also reduced significantly on days 14 day and 21 in mice injected with B16F0/TGF-β1-RNAi tumors. The blood vessel density of the tumors markedly reduced in B16F0/TGF-β1-RNAi tumors. Our results showed that Ad/TGF-β1-RNAi could induce silencing of the TGF-β1 gene effectively. Silencing of TGF-β1 expression in B16F0 cells by RNAi technology can inhibit the growth and metastasis of this tumor after being transplanted to C57BL/6 mice. This kind of adenoviral vector based on RNAi might be a promising vector for cancer therapy.

Analysis of purified wild type and mutant adenovirus particles by SILAC based quantitative proteomics

We used SILAC (stable isotope labelling of amino acids in cell culture) and high-throughput quantitative MS mass spectrometry to analyse the protein composition of highly purified WT wild type adenoviruses, mutant adenoviruses lacking an internal protein component (protein V) and recombinant adenoviruses of the type commonly used in gene therapy, including one virus that had been used in a clinical trial. We found that the viral protein abundance and composition were consistent across all types of virus examined except for the virus lacking protein V, which also had reduced amounts of another viral core protein, protein VII. In all the samples analysed we found no evidence of consistent packaging or contamination with cellular proteins. We believe this technique is a powerful method to analyse the protein composition of this important gene therapy vector and genetically engineered or synthetic virus-like particles. The raw data have been deposited at proteomexchange, identifer PXD001120.

Species D human adenovirus type 9 exhibits better virus-spread ability for antitumor efficacy among alternative serotypes

Species C human adenovirus serotype 5 (HAdV-C5) is widely used as a vector for cancer gene therapy, because it efficiently transduces target cells. A variety of HAdV-C5 vectors have been developed and tested in vitro and in vivo for cancer gene therapy. While clinical trials with HAdV-C5 vectors resulted in effective responses in many cancer patients, administration of HAdV-C5 vectors to solid tumors showed responses in a limited area. A biological barrier in tumor mass is considered to hinder viral spread of HAdV-C5 vectors from infected cells. Therefore, efficient virus-spread from an infected tumor cell to surrounding tumor cells is required for successful cancer gene therapy. In this study, we compared HAdV-C5 to sixteen other HAdV serotypes selected from species A to G for virus-spread ability in vitro. HAdV-D9 showed better virus-spread ability than other serotypes, and its viral progeny were efficiently released from infected cells during viral replication. Although the HAdV-D9 fiber protein contains a binding site for coxsackie B virus and adenovirus receptor (CAR), HAdV-D9 showed expanded tropism for infection due to human CAR (hCAR)-independent attachment to target cells. HAdV-D9 infection effectively killed hCAR-negative cancer cells as well as hCAR-positive cancer cells. These results suggest that HADV-D9, with its better virus-spread ability, could have improved therapeutic efficacy in solid tumors compared to HAdV-C5.

Practical Range of Effective Dose for Cre Recombinase-Expressing Recombinant Adenovirus without Cell Toxicity in Mammalian Cells

The site-specific recombinase Cre is valuable for regulation of gene expression not only in vitro but also in vivo. We previously reported that replication-deficient recombinant adenovirus (rAd) expressing Cre can mediate efficient and strict regulation in 100% of cultured cells. Recently, the constitutive-expression of Cre using retrovirus or lentivirus vector reportedly inhibited cell-growth, but the effect of transient Cre expression have not yet been examined. Here we showed that an excess amount of Cre produced from Cre-expressing rAd caused a deleterious effect in cells even when Cre was transiently expressed. We used three rAds carrying promoters with different activities: the SV40 early promoter (AxSVENCre), the SR alpha promoter (AxSRCre) and the CAG promoter (AxCANCre). Cell toxicity was clearly caused by Cre itself and was distinguishable from that caused by rAd virions when the cytopathic effects of these rAds were compared with that of a control virus lacking the Cre expression unit. Cre toxicity was strongly correlated with the expression level of Cre. Importantly, AxSRCre and AxCANCre gave a 60-fold range of effective MOIs ("effective range") sufficient for gene activation without causing cell toxicity from either the rAd particles or Cre itself, while AxSVENCre failed to give such a range because the expression level of Cre was too low. When Cre was tagged with a nuclear localization signal (NLS), not only its activity but also Cre toxicity was increased fourfold, and the effective range was unchanged. Therefore, AxSRNCre might be more useful to control cell toxicity from the rAd virions than AxSRCre. Cre-induced cell toxicity can be avoided by pre-examining the "effective range" using the purpose cell lines before starting experiments utilizing the experiment of Cre-expressing rAd.