Oncolytic Adenoviral Vector Research Articles

Optimizing Pancreatic Cancer Therapy: The Promise of Immune Stimulatory Oncolytic Viruses.

Pancreatic cancer presents formidable challenges due to rapid progression and resistance to conventional treatments. Oncolytic viruses (OVs) selectively infect cancer cells and cause cancer cells to lyse, releasing molecules that can be identified by the host's immune system. Moreover, OV can carry immune-stimulatory payloads such as interleukin-12, which when delivered locally can enhance immune system-mediated tumor killing. OVs are very well tolerated by cancer patients due to their ability to selectively target tumors without affecting surrounding normal tissues. OVs have recently been combined with other therapies, including chemotherapy and immunotherapy, to improve clinical outcomes. Several OVs including adenovirus, herpes simplex viruses (HSVs), vaccinia virus, parvovirus, reovirus, and measles virus have been evaluated in preclinical and clinical settings for the treatment of pancreatic cancer. We evaluated the safety and tolerability of a replication-competent oncolytic adenoviral vector carrying two suicide genes (thymidine kinase, TK; and cytosine deaminase, CD) and human interleukin-12 (hIL12) in metastatic pancreatic cancer patients in a phase 1 trial. This vector was found to be safe and well-tolerated at the highest doses tested without causing any significant adverse events (SAEs). Moreover, long-term follow-up studies indicated an increase in the overall survival (OS) in subjects receiving the highest dose of the OV. Our encouraging long-term survival data provide hope for patients with advanced pancreatic cancer, a disease that has not seen a meaningful increase in OS in the last five decades. In this review article, we highlight several preclinical and clinical studies and discuss future directions for optimizing OV therapy in pancreatic cancer. We envision OV-based gene therapy to be a game changer in the near future with the advent of newer generation OVs that have higher specificity and selectivity combined with personalized treatment plans developed under AI guidance.

Viral vector production guide part 1: choosing the correct grade for your gene therapy application

This FastFacts will discuss:The most commonly used gene therapy viral vector typesThe manufacturing methods for discovery stage research grade in comparison to larger scale manufacturing for in vivo use, tox studies, and GMP gradeStrategies for selecting the most appropriate grade of material for the intended useJames Cody is the Associate Director Technical Sales and Evaluations, Business Development, Gene Therapy CDMO Services at Charles River Laboratories. He received a PhD in cancer gene therapy from the University of Alabama at Birmingham, working primarily with oncolytic adenoviral vectors, and he completed postdoctoral training at the same institution, evaluating cancer treatment strategies based on oncolytic HSV. After his time at UAB, he then spent four years conducting research in fields including virology, cell biology, cancer, and parasitology. Dr Cody joined Vigene Biosciences in 2018, prior to its integration into Charles River in 2021.

Affilin-based retargeting of adenoviral vectors to the epidermal growth factor receptor

IntroductionTreatment of head and neck squamous cell carcinomas (HNSCC) by oncolytic adenoviral vectors holds promise as an efficient anti-cancer therapy. The epidermal growth factor receptor (EGFR) represents an attractive target receptor since it is frequently overexpressed in many types of HNSCC. MethodsTo achieve EGFR-specific targeting by human adenovirus type 5 (HAdV-5) based vectors, the EGFR affinity ligand Affilin was covalently attached in a position specific manner either to the fiber or the hexon protein of the vector capsid. In vitro and in vivo studies investigated EGFR-specific cancer cell transduction, susceptibility to natural sequestration mechanisms, pharmacokinetics and biodistribution profiles of Affilin-decorated vectors. ResultsAffilin-decorated vectors showed strongly enhanced and EGFR-specific cancer cell transduction in vitro and less susceptibility to known sequestration mechanisms of HAdV-5 particles. However, in vivo neither systemic nor intratumoral vector administration resulted in an improved transduction of EGFR-positive tumors. Comprehensive analyses indicated hampered EGFR-targeting by Affilin-decorated vectors was caused by rapid vector particle consumption due to binding to the murine EGFR, insufficient tumor vascularization and poor target accessibility for Affilin in the solid tumor caused by a pronounced tumor stroma. ConclusionIn vitro studies yielded proof-of-concept results demonstrating that covalent attachment of a receptor-specific Affilin to the adenoviral capsid provides an effective and versatile tool to address cancer-specific target receptors by adenoviral vectors. Regarding EGFR as the vector target, off-target tissue transduction and low receptor accessibility within the tumor tissue prevented efficient tumor transduction by Affilin-decorated vectors, rendering EGFR a difficult-to-target receptor for adenoviral vectors.

Role of Adenoviruses in Cancer Therapy.

Cancer is one of the leading causes of death in the world, which is the second after heart diseases. Adenoviruses (Ads) have become the promise of new therapeutic strategy for cancer treatment. The objective of this review is to discuss current advances in the applications of adenoviral vectors in cancer therapy. Adenoviral vectors can be engineered in different ways so as to change the tumor microenvironment from cold tumor to hot tumor, including; 1. by modifying Ads to deliver transgenes that codes for tumor suppressor gene (p53) and other proteins whose expression result in cell cycle arrest 2. Ads can also be modified to express tumor specific antigens, cytokines, and other immune-modulatory molecules. The other strategy to use Ads in cancer therapy is to use oncolytic adenoviruses, which directly kills tumor cells. Gendicine and Advexin are replication-defective recombinant human p53 adenoviral vectors that have been shown to be effective against several types of cancer. Gendicine was approved for treatment of squamous cell carcinoma of the head and neck by the Chinese Food and Drug Administration (FDA) agency in 2003 as a first-ever gene therapy product. Oncorine and ONYX-015 are oncolytic adenoviral vectors that have been shown to be effective against some types of cancer. The Chiness FDA agency has also approved Oncorin for the treatment of head and neck cancer. Ads that were engineered to express immune-stimulatory cytokines and other immune-modulatory molecules such as TNF-α, IL-2, BiTE, CD40L, 4-1BBL, GM-CSF, and IFN have shown promising outcome in treatment of cancer. Ads can also improve therapeutic efficacy of immune checkpoint inhibitors and adoptive cell therapy (Chimeric Antigen Receptor T Cells). In addition, different replication-deficient adenoviral vectors (Ad5-CEA, Ad5-PSA, Ad-E6E7, ChAdOx1–MVA and Ad-transduced Dendritic cells) that were tested as anticancer vaccines have been demonstrated to induce strong antitumor immune response. However, the use of adenoviral vectors in gene therapy is limited by several factors such as pre-existing immunity to adenoviral vectors and high immunogenicity of the viruses. Thus, innovative strategies must be continually developed so as to overcome the obstacles of using adenoviral vectors in gene therapy.

Hydrogel-based co-delivery of CIK cells and oncolytic adenovirus armed with IL12 and IL15 for cancer immunotherapy

Intratumoral injection of various effector cells combined with oncolytic adenovirus expressing antitumor cytokines exert an effective antitumor immune effect by oncolysis and altering the tumor microenvironment. However, this combination therapy had certain limitations. When used in high concentrations, effector cells and oncolytic viruses can spread rapidly to surrounding non-target tissues. And because both therapies used in combination are immunogenic and exhibit shorter biological activity, multiple injections were required to attain an adequate therapeutic index. To overcome these drawbacks, we encapsulated gelatin-based hydrogel capable of co-deliver oncolytic adenovirus armed with IL12 and IL15 (CRAd-IL12-IL15) and CIK cells for enhancing and prolonging the antitumor effects of both therapies after a single intratumoral injection. The injectable and biodegradable hydrogel reduced the dispersion of high-dose oncolytic adenovirus and CIK cells from the injection site to the liver and other non-target tissues. In this study, a novel oncolytic adenoviral vector CRAd-IL12-IL15 was constructed to verify the cytokine expression and oncolytic ability, which can upregulate the expression levels of Bcl-2, Cish and Gzmb in tumor cells. The CRAd-IL12-IL15 + CIKs/gelatin treatment maintained sustained release of CRAd-IL12-IL15 and active CIK cells over a longer period of time, attenuating the antiviral immune response against adenovirus. In conclusion, the results suggested that hydrogel-mediated co-delivery of CRAd-IL12-IL15 and CIK cells might be a an approach to overcome limitations. Both treatments could be effectively retained in tumor tissue and sustained to induce potent anti-tumor immune responses with a single administration.

Concepts in Oncolytic Adenovirus Therapy.

Oncolytic adenovirus therapy is gaining importance as a novel treatment option for the management of various cancers. Different concepts of modification within the adenovirus vector have been identified that define the mode of action against and the interaction with the tumour. Adenoviral vectors allow for genetic manipulations that restrict tumour specificity and also the expression of specific transgenes in order to support the anti-tumour effect. Additionally, replication of the virus and reinfection of neighbouring tumour cells amplify the therapeutic effect. Another important aspect in oncolytic adenovirus therapy is the virus induced cell death which is a process that activates the immune system against the tumour. This review describes which elements in adenovirus vectors have been identified for modification not only to utilize oncolytic adenovirus vectors into conditionally replicating adenoviruses (CRAds) that allow replication specifically in tumour cells but also to confer specific characteristics to these viruses. These advances in development resulted in clinical trials that are summarized based on the conceptual design.

The genome position of a therapeutic transgene strongly influences the level of expression in an armed oncolytic human adenovirus vector

Efficacy of oncolytic, conditionally-replicating adenovirus (CRAd) vectors can be enhanced by “arming” the vector with therapeutic transgenes. We examined whether inclusion of an intact early region 3 (E3) and the reptilian reovirus fusogenic p14 fusion-associated small transmembrane (FAST) protein enhanced vector efficacy. The p14 FAST transgene was cloned between the fiber gene and E4 region, with an upstream splice acceptor for replication-dependent expression from the major late promoter. In A549 cells, this vector expressed p14 FAST protein at very low levels, and showed a poor ability to mediate cell-cell fusion, relative to a similar vector encoding p14 FAST within the E3 deletion. Although expression of E3 proteins from the CRAd increased plaque size, poor expression of p14 FAST protein compromised the fusogenic capacity of the vector. Thus, location of a therapeutic transgene within a CRAd can significantly impact expression of the transgene and is an important consideration in vector design.

Metabolome-Driven Regulation of Adenovirus-Induced Cell Death.

A viral infection that involves virus invasion, protein synthesis, and virion assembly is typically accompanied by sharp fluctuations in the intracellular levels of metabolites. Under certain conditions, dramatic metabolic shifts can result in various types of cell death. Here, we review different types of adenovirus-induced cell death associated with changes in metabolic profiles of the infected cells. As evidenced by experimental data, in most cases changes in the metabolome precede cell death rather than represent its consequence. In our previous study, the induction of autophagic cell death was observed following adenovirus-mediated lactate production, acetyl-CoA accumulation, and ATP release, while apoptosis was demonstrated to be modulated by alterations in acetate and asparagine metabolism. On the other hand, adenovirus-induced ROS production and ATP depletion were demonstrated to play a significant role in the process of necrotic cell death. Interestingly, the accumulation of ceramide compounds was found to contribute to the induction of all the three types of cell death mentioned above. Eventually, the characterization of metabolite analysis could help in uncovering the molecular mechanism of adenovirus-mediated cell death induction and contribute to the development of efficacious oncolytic adenoviral vectors.

Tropism and transduction of oncolytic adenovirus vectors in prostate cancer therapy.

Oncolytic adenovirus has been applied in cancer therapy because of several advantages such as cost-effective production, high transduction efficiency and low toxicity. Recent efforts have been focused on the modification of oncolytic adenovirus by encoding transgenes within the viral genome to efficiently and selectively replicate within cancer cells, destroy cancerous cells, induce tumor cell apoptosis, and stimulate the recruitment of immune cells to the tumor site. Nevertheless, there are still big challenges for translational research of oncolytic virotherapy in clinical cancer management. Therefore, here we summarize current status on the design and application of oncolytic adenovirus vectors for prostate cancer therapy. In particular, we describe the main receptors associated with the tropism and transduction of oncolytic adenovirus vectors, and propose new directions in future studies for prostate cancer virotherapy.

CXCL12 Retargeting of an Oncolytic Adenovirus Vector to the Chemokine CXCR4 and CXCR7 Receptors in Breast Cancer.

Breast cancer is the most frequently diagnosed cancer in women under 60, and the second most diagnosed cancer in women over 60. While significant progress has been made in developing targeted therapies for breast cancer, advanced breast cancer continues to have high mortality, with poor 5-year survival rates. Thus, current therapies are insufficient in treating advanced stages of breast cancer; new treatments are sorely needed to address the complexity of advanced-stage breast cancer. Oncolytic virotherapy has been explored as a therapeutic approach capable of systemic administration, targeting cancer cells, and sparing normal tissue. In particular, oncolytic adenoviruses have been exploited as viral vectors due to their ease of manipulation, production, and demonstrated clinical safety profile. In this study, we engineered an oncolytic adenovirus to target the chemokine receptors CXCR4 and CXCR7. The overexpression of CXCR4 and CXCR7 is implicated in the initiation, survival, progress, and metastasis of breast cancer. Both receptors bind to the ligand, CXCL12 (SDF-1), which has been identified to play a crucial role in the metastasis of breast cancer cells. This study incorporated a T4 fibritin protein fused to CXCL12 into the tail domain of an adenovirus fiber to retarget the vector to the CXCR4 and CXCR7 chemokine receptors. We showed that the modified virus targets and infects CXCR4- and CXCR7-overexpressing breast cancer cells more efficiently than a wild-type control vector. In addition, the substitution of the wild-type fiber and knob with the modified chimeric fiber did not interfere with oncolytic capability. Overall, the results of this study demonstrate the feasibility of retargeting adenovirus vectors to chemokine receptor-positive tumors.

3D-printed ordered bed structures for chromatographic purification of enveloped and non-enveloped viral particles

In the last few decades we have witnessed a rapid advance in the design of new biotherapeutic products using viral particles. The current limitations of manufacturing these particles are often associated with their purification processes. Additive manufacturing opened the possibility of printing 3D porous chromatographic structures to be used in the bio-separation field. Here, we report the production and use of 3D-printed cellulose chromatographic columns functionalized with two different ligands: diethylaminoethyl (DEAE) and hydroxyapatite for the purification of oncolytic adenovirus and lentiviral vectors. Porous beds with ordered channel structures can be manufactured to achieve separations that are efficient and tailored to the target products. While common chromatographic beads are based on non-ordered bed structures, in this work we explore the use of a triply periodic minimal surface, the Schoen Gyroid, to create bed structures with a channel size of 300 µm in diameter. The dynamic binding capacity (DBC) obtained for non-enveloped oncolytic adenovirus using the 3D-printed DEAE column (1.9 × 1010 viral genomes per millilitre) was consistent with the reported values in the literature for this virus particle. We also demonstrate that by using these 3D-printed chromatographic supports, oncolytic adenoviruses were successfully purified with a recovery yield of 69 ± 6%, while maintaining their size and shape as observed by electron microscopy analysis. For lentiviral vectors, a DBC of 2 × 109 physical particles per millilitre was achieved for the DEAE column. Moreover, these enveloped viruses were purified using this 3D-printed column with a recovery yield of 57% of transducing units. These findings suggest, with advancements, 3D printing technologies applied in the viral vector manufacturing field could improve downstream process efficiency.

Enhancing the antitumor activity of an engineered TRAIL-coated oncolytic adenovirus for treating acute myeloid leukemia

The use of oncolytic viruses has emerged as a promising therapeutic approach due to the features of these viruses, which selectively replicate and destroy tumor cells while sparing normal cells. Although numerous oncolytic viruses have been developed for testing in solid tumors, only a few have been reported to target acute myeloid leukemia (AML) and overall patient survival has remained low. We previously developed the oncolytic adenovirus rAd5pz-zTRAIL-RFP-SΔ24E1a (A4), which carries the viral capsid protein IX linked to tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) and results in increased infection of cancer cells and improved tumor targeting. To further improve the therapeutic potential of A4 by enhancing the engagement of virus and leukemia cells, we generated a new version of A4, zA4, by coating A4 with additional soluble TRAIL that is fused with a leucine zipper-like dimerization domain (zipper). ZA4 resulted in enhanced infectivity and significant inhibition of the proliferation of AML cells from cell lines and primary patient samples that expressed moderate levels of TRAIL-related receptors. ZA4 also elicited enhanced anti-AML activity in vivo compared with A4 and an unmodified oncolytic adenoviral vector. In addition, we found that the ginsenoside Rh2 upregulated the expression of TRAIL receptors and consequently enhanced the antitumor activity of zA4. Our results indicate that the oncolytic virus zA4 might be a promising new agent for treating hematopoietic malignancies such as AML.

A tropism-transformed Oncolytic Adenovirus with Dual Capsid Modifications for enhanced Glioblastoma Therapy.

Glioblastoma, the most common human brain tumor, is highly invasive and difficult to cure using conventional cancer therapies. As an alternative, adenovirus-mediated virotherapies represent a popular and maturing technology. However, the cell surface coxsackievirus and adenovirus receptor (CAR)-dependent infection mechanism limits the infectivity and oncolytic effects of Adenovirus type 5. To address this limitation, in this study we aimed to develop a novel oncolytic adenovirus for enhanced infectivity and therapeutic efficacy toward glioblastoma. We developed a novel genetically modified oncolytic adenovirus vector with dual capsid modifications to facilitate infection and specific cytotoxicity toward glioma cells. Modification of the adenoviral capsid proteins involved the incorporation of a synthetic leucine zipper-like dimerization domain into the capsid protein IX (pIX) of human adenovirus serotype 5 (Ad5) and the exchange of the fiber knob from Ad37. The virus infection mechanism and anti-tumor efficacy of modified vectors were evaluated in both in vitro (cell) and in vivo (mouse) models. Ad37-knob exchange efficiently promoted the virus infection and replication-induced glioma cell lysis by oncolytic Ad5. We also found that gene therapy mediated by the dual-modified oncolytic Ad5 vector coupled with the tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) exhibited significantly enhanced anti-tumor efficacy in vitro and in vivo. This genetically modified oncolytic adenovirus provides a promising vector for future use in glioblastoma gene-viral-based therapies.

Novel Combination Oncolytic Adenoviral Gene Therapy Armed with Dm-dNK and CD40L for Breast Cancer.

Both Drosophila melanogaster deoxyribonucleoside kinase (Dm-dNK) suicide gene therapy and exogenous CD40 ligand (CD40L)-CD40 interaction in cancer via conditionally replicating adenovirus can selectively kill tumors without damaging normal tissues. To further improve the cancer killing effect, we investigated the therapeutic effect of combined cancer gene therapy based on a selective oncolytic adenovirus vector containing Dm-dNK suicide gene and exogenous CD40L on breast carcinoma cells in vitro and in vivo. A series of conditionally replicating adenoviruses using adenovirus vector P74 were generated: P74-dNK, P74-CD40L (expressing Dm-dNK or CD40L respectively), and P74-dNK-CD40L (expressing combined Dm-dNK and CD40L). Breast cancer cell lines (MDA-MB-231, MCF-7) and non-tumor cell line (MRC5) were treated with adenovirus and cytotoxicity determined by MTT assay, and apoptosis assessed by flow cytometry after 72h. We also assessed in vivo cell killing efficiency using a mouse xenograft model with MDA-MB-231 cells. Co-expression of Dm-dNK and CD40L reduced cell proliferation of MDAMB- 231 or MCF7 cancer cells, and induced more apoptosis in TERT and CD40 positive cancer cells, but not normal MRC5 cells. Significant reduction in tumor volume was also seen in combined treatment arms as compared to any single treatment. Our data suggest enhanced, selective tumor cell killing using combined gene therapy with conditionally replicating adenovirus containing Dm-dNK suicide gene and exogenous CD40 ligation (CD40L-CD40).

IFN Expressing Oncolytic Adenovirus as a Tool to Improve Pancreatic Cancer Therapy

Pancreatic Ductal Adenocarcinoma (PDAC) is the 3rd cause of cancer related death in the US. Aside from surgery, which is not applicable to 80% of patients, there is no highly effective therapy to treat the disease. Due to late diagnosis and advanced disease, PDAC patients live 3–6 months post‐diagnosis and 5‐year survival is 6%. Despite this discouraging scenario, clinical trials testing use of adjuvant therapy combined with IFN‐α (IFN), 5‐FU, CDDP, and radiation improved the 2‐year survival of patients by 20–41%, and the 5‐year survival by 35%. While efficacious, IFN‐therapy drawbacks included high IFN systemic toxicity, increasing patient drop‐out from trials, and low levels of the cytokine in tumors, reducing chemo‐radio sensitization of IFN in tumors. Aiming to perfect this promising therapy, we studied the use of IFN‐expressing oncolytic adenovirus (OAd) vectors in combination with chemoradiation mimicking the aforementioned IFN‐chemoradiation based clinical trials. As IFN can stimulate tumor specific immune response, we first evaluated the effect of a hamster IFN expressing vector (OAd‐hamIFN) in a syngeneic immunocompetent hamster model of PDAC. To analyse the interaction of OAd with chemotherapy and radiation without the interference of the immune system, we later accessed the effect of a human IFN‐expressing vector (OAd‐IFN) in immunodeficient mice bearing human PDAC xenografts. In both studies, OAd vectors included 5/3 fiber modification to enhance infectivity in PDAC cells, over expressed Adenovirus Death Protein (ADP) to potentiate cell oncolysis, and expressed IFN in a replication dependent manner. As PDAC cells upregulate Cox‐2, we used the Cox‐2 promoter in the OAd‐IFN to restrict viral replication to human PDAC cells. Data showed that combinations of 5‐FU, radiation, and 5‐FU + radiation with either OAd‐hamIFN in hamster PDAC cells, or OAd‐IFN in human PDAC cells resulted in highly synergistic and cytotoxic combinations in vitro. Studies in immunocompetent hamsters showed that use of OAd‐hamIFN in combination with therapeutics used in IFN‐therapy improved treatment efficacy, and that use of the virus mimicking the IFN‐therapy was the most efficacious treatment. When analyzing effect of OAd‐IFN in combination with 5‐FU + CDDP in human PDAC cells, combinations were shown to be antagonistic and weakly cytotoxic. However, addition of radiation to treatment (OAd‐IFN + (5‐FU + CDDP) + radiation) overruled chemotherapy antagonism, resulting in highly synergistic and extremely potent treatments in vitro and in mice bearing PDAC xenografts. As radiation was shown to abolish antagonism of chemotherapy to virus in vivo, we tested different radiation protocols in combination with virus. We concluded that the best radiation protocol comprised of infecting tumors before irradiation. In summary, our data strongly supported inclusion of an IFN expressing OAd in treatments mimicking IFN‐therapy. As this therapy is one of the few showing an impact in patient survival, improvement of therapy with the virus might finally result in an potent treatment against PDAC.Support or Funding InformationNIH/NCIP50CA101955, NIH/NCIR01CA094084This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

First in Human Study of NG-350A (an Oncolytic Adenoviral Vector Which Expresses an Anti-CD40 Antibody)

First in Human Study of NG-350A (an Oncolytic Adenoviral Vector Which Expresses an Anti-CD40 Antibody)

Peptide Nucleic Acid-Functionalized Adenoviral Vectors Targeting G-Quadruplexes in the P1 Promoter of Bcl-2 Proto-Oncogene: A New Tool for Gene Modulation in Anticancer Therapy.

The B-cell lymphoma 2 (Bcl-2) gene encodes for an antiapoptotic protein associated with the onset of many human tumors. Several oligonucleotides (ONs) and ON analogues are under study as potential tools to counteract the Bcl-2 expression. Among these are Peptide Nucleic Acids (PNAs). The absence of charges on PNA backbones allows the formation of PNA/DNA complexes provided with higher stability than the corresponding natural DNA/DNA counterparts. To date, the use of PNAs in antigene or antisense strategies is strongly limited by their inability to efficiently cross the cellular membranes. With the aim of downregulating the expression of Bcl-2, we propose here a novel antigene approach which uses oncolytic adenoviral vectors (OAds) as a new cancer cell-targeted PNA delivery system. The ability of oncolytic Ad5D24 vectors to selectively infect and kill cancer cells was exploited to transfect with high efficiency and selectivity a short cytosine-rich PNA complementary to the longest loop of the main G-quadruplex formed by the 23-base-long bcl2midG4 sequence located 52-30 bp upstream of the P1 promoter of Bcl-2 gene. Physico-chemical and biological investigations confirmed the ability of the PNA-conjugated Ad5D24 vectors to load and transfect their PNA cargo into human A549 and MDA-MB-436 cancer cell lines, as well as the synergistic (OAd+PNA) cytotoxic effect against the same cell lines. This approach holds promise for safer chemotherapy because of reduced toxicity to healthy tissues and organs.

The practical self-targeted oncolytic adenoviral nanosphere based on immuno-obstruction method via polyprotein surface precipitation technique enhances transfection efficiency for virotherapy

Recent developments in tumour treatment had focused on virotherapies that were currently revolutionising new innovated treatment pathways. This study focused on the fabrication of oncolytic adenoviral vector (Ad) nanosphere that self-targeted at lung tumour cells (A549), utilising the immune response for upper respiratory tract infection, caused by the Ad infection. This system was dependent upon T-cell immune response, surface charge and blood metabolism. Oncolytic Ad attacked lung A549 tumour cells by incorporated its own DNA to replace A549's, the triggered immune response generated T-cells also further attack A549. Direct Ad injection was demonstrated to be lethal and prohibited in vivo. In this research a multifunctional principal using polyprotein surface precipitation technique (PSP) whist maintaining biological controls for self-assembly polyprotein Ad nanosphere both biocompatible and reproducible, was demonstrated as a result of the enhanced transfection efficiency and a successful multifunctional drug delivery system for virotherapy.

Poly-Gamma-Glutamic Acid (γ-PGA)-Based Encapsulation of Adenovirus to Evade Neutralizing Antibodies

In recent years, there has been an increasing interest in oncolytic adenoviral vectors as an alternative anticancer therapy. The induction of an immune response can be considered as a major limitation of this kind of application. Significant research efforts have been focused on the development of biodegradable polymer poly-gamma-glutamic acid (γ-PGA)-based nanoparticles used as a vector for effective and safe anticancer therapy, owing to their controlled and sustained-release properties, low toxicity, as well as biocompatibility with tissue and cells. This study aimed to introduce a specific destructive and antibody blind polymer-coated viral vector into cancer cells using γ-PGA and chitosan (CH). Adenovirus was successfully encapsulated into the biopolymer particles with an encapsulation efficiency of 92% and particle size of 485 nm using the ionic gelation method. Therapeutic agents or nanoparticles (NPs) that carry therapeutics can be directed specifically to cancerous cells by decorating their surfaces using targeting ligands. Moreover, in vitro neutralizing antibody response against viral capsid proteins can be somewhat reduced by encapsulating adenovirus into γ-PGA-CH NPs, as only 3.1% of the encapsulated adenovirus was detected by anti-adenovirus antibodies in the presented work compared to naked adenoviruses. The results obtained and the unique characteristics of the polymer established in this research could provide a reference for the coating and controlled release of viral vectors used in anticancer therapy.

Oncolyic adenovirus SG600-IL24 expressing human melanoma differentiation associated gene-7/interleukin-24 selectively induces growth arrests and apoptosis in hepatocellular carcinoma cell lines

Objective To investigate the effect of oncolytic adenovirus vector SG600-IL24 expressing human melanoma differentiation associated gene-7/interleukin-24 (MDA-7/IL-24) on hepatocellular carcinoma cell lines with different metastatic potentials (HepG2, Hep3B, SMMC7721 and normal liver cell line L02). Methods The oncolytic adenovirus SG600-IL24 carrying MDA-7/IL-24 gene was transfected into hepatocellular carcinoma cell lines and normal liver cell line. The mRNA and protein expression of MDA-7/IL-24 in HepG2, Hep3B, SMMC7721 and L02 cells was confirmed by reverse transcriptase-polymerase chain reaction (RT-PCR), enzyme linked immunosorbent assay (ELISA) and Western blotting respectively. Methyl thiazol tetrazolium (MTT) assay and flow cytometry were used to study tumor cell proliferation and cell cycle in vitro. Hoechst 33258 and flow cytometry were studied to indicate the apoptosis effects. Results It was confirmed by RT-PCR, ELISA and Western blotting that the exogenous MDA-7/IL-24 gene was highly expressed in HepG2, Hep3B, SMMC7721 and L02 cells. MTT and apoptosis detection indicated that MDA-7/IL-24 could induce the growth suppression [inhibition rate: (75.0±2.5)%, (85.0±2.0)%, and (86.0±3.5)% respectively. for HepG2: F=5.860; for Hep3B: F=7.210; for SMMC7721: F=7.980, P=0.000], promote apoptosis [apoptosis rate: (56.5±4.0)%, (34.4±2.0)% and (43.3±2.5)% respectively. For HepG2: F=203.400; for Hep3B: F=313.200; for SMMC7721: F=130.500, P=0.000], and block cancer cells in G2/M phase [the blocking rate: (35.4±4.2)%, (47.3±6.2)% and (40.5±5.0)%] but not L02 cells. Conclusion Oncolytic adenovirus vector SG600-IL24 can selectively induce growth suppression and promote apoptosis in hepatocellular carcinoma lines in vitro but not in L02 cells. Key words: Carcinoma, hepatocellular; Oncolytic viruses; Melanoma differentiation associated gene-7/interleukin-24 gene; Gene therapy