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Abstract Extracellular vesicles (EVs), are naturally occurring cargo delivery tools with the potential to be used as drug vehicles of single agents or combination therapies. We previously demonstrated that human lung cancer cell-derived EVs could be used for the systemic delivery of oncolytic virus (OVs) and chemotherapy drugs such as paclitaxel (PTX), leading to enhanced anti-tumor effects in nude mice. In the current work, we evaluated the biodistribution of EVs by using bioluminescence and fluorescence imaging technologies, thus proving the ability of these EVs-formulations to specifically target the neoplasia, while leaving other body tissues unaffected. Moreover, in vivo imaging of NFκB activation in an immunocompetent reporter mouse model allowed to demonstrate the selective ability of EVs to induce tumor-associated inflammatory reactions, which are characterized by immunogenic cell death and CD3+/CD4+/CD8+ T-cell infiltration. While EVs have the potential to induce a systemic immune reaction by pro-inflammatory cytokines, our study provides compelling evidences of a localized inflammatory effect in the peritumoral area. Collectively, our findings strongly support the systemic administration of EVs formulations with OVs alone or in combination with chemotherapy agents as a novel strategy aimed at treating primary and metastatic cancers. Graphical abstract Unlabelled Image [ABSTRACT FROM AUTHOR]

Genetic replacement of adenoviral fiber knobs by ligands that enable tumor specific targeting of oncolytic adenoviruses is challenging because the fiber knob contributes to virus assembly. Here, we present a novel concept by describing stable recombinant adenoviruses with tumor specific infection mode. The fiber knob was replaced by endosialidaseNF (endoNF), the tailspike protein of bacteriophage K1F. EndoNF recognizes polysialic acid, an oncofetal antigen characteristic for high malignant tumors of neuroendocrine origin. An intramolecular chaperone contained in endoNF warrants folding and compensates for the knob function in virus assembly. Obtained recombinant viruses demonstrated polysialic acid dependent infection modes, strong oncolytic capacity with polysialic acid positive cells in culture and a high potential to inhibit tumor growth in a therapeutic mouse model of subcutaneous neuroblastoma. With a single genetic manipulation we achieved ablation of the fiber knob, introduction of a tumor specific ligand, and folding control over the chimeric fiber construct. [ABSTRACT FROM AUTHOR]

The effective antitumor immune responses are dependent on coordinate interaction of various effector cells. Thus, the combination of adoptive immunotherapy and target gene therapy is capable of efficiently generating a productive antitumor immune response. We investigated whether combination of cytokine-induced killer (CIK) cells adoptive immunotherapy and CCL21/IL15 armed oncolytic adenovirus could induce the enhanced antitumor activity. The CCL21/IL15 co-expression oncolytic adenoviruses were constructed by using the AdEasy system, which uses homologous recombination with shuttle plasmids and full length Ad backbones. This conditionally replicating adenoviruses CRAd-CCL21-IL15 could induce apoptosis in TERTp-positive tumor cells for viral propagation, but do not replicate efficiently in normal cells, because the E1A promoter was replaced by telomerase reverse transcriptase promoter (TERTp). Our results showed that the combination of CIK cells and CRAd-CCL21-IL15 could induce higher antitumor activity than either CIK cells or CRAd-CCL21-IL15 alone. This combined treatment could induce the tumor specific cytotoxicity of CTLs (cytotoxic T lymphocytes) in vitro. Moreover, the treatment of established tumors with the combined therapy of CIK cells and CRAd-CCL21-IL15 resulted in tumor regression. This study suggests that the combined treatment by adoptive immunotherapy and gene therapy is a promising strategy for the therapy of tumor. [ABSTRACT FROM AUTHOR]

Multigene-armed oncolytic adenoviruses are capable of efficiently generating a productive antitumor immune response. The chemokine (C-C motif) ligand 21 (CCL21) binds to CCR7 on naïve T cells and dendritic cells (DCs) to promote their chemoattraction to the tumor and resultant antitumor activity. Interleukin 21 (IL21) promotes survival of naïve T cells while maintaining their CCR7 surface expression, which increases their capacity to transmigrate in response to CCL21 chemoattraction. IL21 is also involved in NK cell differentiation and B cell activation and proliferation. The generation of effective antitumor immune responses is a complex process dependent upon coordinated interactions of various subsets of effector cells. Using the AdEasy system, we aimed to construct an oncolytic adenovirus co-expressing CCL21 and IL21 that could selectively replicate in TERTp-positive tumor cells (Ad-CCL21-IL21 virus). The E1A promoter of these oncolytic adenoviruses was replaced by telomerase reverse transcriptase promoter (TERTp). Ad-CCL21-IL21 was constructed from three plasmids, pGTE-IL21, pShuttle-CMV-CCL21 and AdEasy-1 and was homologously recombined and propagated in the Escherichia coli strain BJ5183 and the packaging cell line HEK-293, respectively. Our results showed that our targeted and armed oncolytic adenoviruses Ad-CCL21-IL21 can induce apoptosis in TERTp-positive tumor cells to give rise to viral propagation, in a dose-dependent manner. Importantly, we confirm that these modified oncolytic adenoviruses do not replicate efficiently in normal cells even under high viral loads. Additionally, we investigate the role of Ad-CCL21-IL21 in inducing antitumor activity and tumor specific cytotoxicity of CTLs in vitro. This study suggests that Ad-CCL21-IL21 is a promising targeted tumor-specific oncolytic adenovirus. [ABSTRACT FROM AUTHOR]

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. [Display omitted] • We constructed a IL12 and IL15 co-expression conditionally replicating oncolytic adenoviruses (CRAd-IL12-IL15). • We encapsulated gelatin-based hydrogel capable of co-deliver CRAd-IL12-IL15 and CIK cells. • The injectable and biodegradable hydrogel reduced the dispersion of high-dose oncolytic adenovirus and CIK cells. [ABSTRACT FROM AUTHOR]

Abstract: Oncolytic adenoviruses have been used in different preclinical and clinical studies, showing their capacity to kill tumor cells without major adverse events. However, these studies also underline the limitations of this approach. The efficacy of oncolytic adenoviruses is hampered by their limited ability to transduce some tumor types, their lack of selectivity, and their poor dissemination within tumors. In addition, the host immune response may limit oncolytic adenovirus efficacy. Combining oncolytic adenoviruses with chemotherapeutics constitutes an appealing strategy to increase their potency. The first part of this review describes the molecular basis of oncolytic adenoviruses, their use in preclinical studies and clinical trials, their limitations, and strategies to circumvent these limitations. The second part will focus on studies combining oncolytic adenoviruses with chemotherapeutic drugs, including standard chemotherapeutic drugs, molecularly targeted drugs, and other drugs that have been combined with oncolytic adenoviruses. Finally, based on these studies, we describe future directions and general rules that could be followed to identify chemotherapeutic drugs displaying additive/synergistic effects when combined with oncolytic adenoviruses. [Copyright &y& Elsevier]

Abstract: Head and neck squamous cell carcinoma (HNSCC) is a common and often devastating disease without curative treatment when advanced or recurrent. The aim of this study was to assess whether capsid-modified oncolytic adenoviruses have therapeutic efficacy in HNSCC low passage tumour cell cultures and if it could be further improved by combination with cetuximab, radiotherapy and chemotherapy. We investigated which adenoviral capsid modifications allow best gene transfer and cell killing of HNSCC substrates. Gene transfer was assessed using replication-deficient adenoviruses expressing luciferase. Cell killing was studied in vitro and in vivo using oncolytic adenoviruses, which kill tumour cell by viral replication. The most effective capsid-modified oncolytic adenoviruses were combined with HNSCC standard therapies and their efficacy was assessed in vitro as well as in vivo. Cell killing was assessed in vitro by MTS assay and in vivo by HNSCC subcutaneous tumour growth follow-up in nude mice. Cetuximab treatment was found to enrich CD133+ and CD44+ tumour-initiating type cells in tumours grown in mice. Capsid-modified viruses showed increased transduction and oncolysis of HNSCC substrates in comparison to Ad5-based agents. Polylysine (pK7)-modified oncolytic virus resulted in significant tumour growth reduction in vivo. Combination of chemotherapy (cisplatin and 5-fluorouracil), radiotherapy and cetuximab with oncolytic adenovirus therapy resulted in further increases in cell killing effect in vitro and complete eradication of tumours in vivo. Our pre-clinical data suggest that it is feasible and efficacious to combine oncolytic adenoviruses with HNSCC standard therapies into a multimodality treatment regimen for clinical testing in HNSCC patients. [Copyright &y& Elsevier]

Treatment options for pancreatic cancer have limited success and it is therefore an appropriate target for the development of new strategies, including gene therapy. Gene therapy approaches include inhibition of activated oncogenes (KRAS, LSM1) with antisense and RNA interference strategies, replacement of inactivated tumour suppressor genes (TP53, CDKN2A, CDKN1A), targeting of cell signalling pathways, gene-directed prodrug-activation therapies and the use of replication-competent oncolytic viruses. Angiogenesis and apoptosis have also been targeted for gene therapy. Clinical trials of gene therapy have shown only moderate anti-tumour effects. As there are many genetic abnormalities in pancreatic cancer, strategies combining different targets or indeed different modalities of treatment, may be more successful. Identification of new targets and improvements in delivery and targeting may further improve the efficacy of gene therapy in pancreatic cancer. [Copyright &y& Elsevier]