Mathematical modelling of the interaction between cancer cells and an oncolytic virus: insights into the effects of treatment protocols

Oncolytic virotherapy is an experimental cancer treatment that uses genetically engineered viruses to target and kill cancer cells. One major limitation of this treatment is that virus particles are rapidly cleared by the immune system, preventing them from arriving at the tumour site. To improve virus survival and infectivity modified virus particles with the polymer polyethylene glycol (PEG) and the monoclonal antibody herceptin. While PEG modification appeared to improve plasma retention and initial infectivity it also increased the virus particle arrival time. We derive a mathematical model that describes the interaction between tumour cells and an oncolytic virus. We tune our model to represent the experimental data by Kim et al. (2011) and obtain optimised parameters. Our model provides a platform from which predictions may be made about the response of cancer growth to other treatment protocols beyond those in the experiments. Through model simulations we find that the treatment protocol affects the outcome dramatically. We quantify the effects of dosage strategy as a function of tumour cell replication and tumour carrying capacity on the outcome of oncolytic virotherapy as a treatment. The relative significance of the modification of the virus and the crucial role it plays in optimising treatment efficacy is explored.Comment: 15 pages, 6 figure

Markedly enhanced intratumoral spread and antitumor effect of oncolytic adenovirus expressing decorin

With the aim of improving viral distribution and tumor penetration, we have engineered decorin expressing replication-incompetent (dl-LacZ-DCNG) and -competent (Ad-[DELTA]E1B-DCNG) adenoviruses. In both tumor spheroids and established solid tumors in vivo, administration of dl-LacZ-DCNG resulted in greater transduction efficiency and viral spread throughout the tumor mass. Ad-[DELTA]E1B-DCNG also enhanced viral distribution and tumor spread, leading to an increased anti-tumor effect and survival advantage. Upon histological analysis, Ad-[DELTA]E1B-DCNG also elicited greater percentage of apoptotic cells and extensive necrosis compared to those from untreated or control virus-treated tumors. Furthermore, Ad-[DELTA]E1B-DCNG substantially decreased extracellular matrix components within the tumor tissue, while normal tissue adjacent to the tumor was not affected. Finally, intratumoral administration of Ad-[DELTA]E1B-DCNG did not enhance but inhibited the formation of pulmonary metastases of B16BL6 melanoma cells in mice. Taken together, these data demonstrate the utility of decorin as a dispersion agent and suggest its utility and potential in improving the efficacy of replicating adenovirus-mediated cancer gene therapy

Selective disruption of an oncogenic mutant allele by CRISPR/Cas9 induces efficient tumor regression

Approximately 15% of non-small cell lung cancer cases are associated with a mutation in the epidermal growth factor receptor (EGFR) gene, which plays a critical role in tumor progression. With the goal of treating mutated EGFR-mediated lung cancer, we demonstrate the use of clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR associated protein 9 (Cas9) system to discriminate between the oncogenic mutant and wild-type EGFR alleles and eliminate the carcinogenic mutant EGFR allele with high accuracy. We targeted an EGFR oncogene harboring a single-nucleotide missense mutation (CTG > CGG) that generates a protospacer-adjacent motif sequence recognized by the CRISPR/Cas9 derived from Streptococcus pyogenes. Co-delivery of Cas9 and an EGFR mutation-specific single-guide RNA via adenovirus resulted in precise disruption at the oncogenic mutation site with high specificity. Furthermore, this CRISPR/Cas9-mediated mutant allele disruption led to significantly enhanced cancer cell killing and reduced tumor size in a xenograft mouse model of human lung cancer. Taken together, these results indicate that targeting an oncogenic mutation using CRISPR/Cas9 offers a powerful surgical strategy to disrupt oncogenic mutations to treat cancers; similar strategies could be used to treat other mutation-associated diseases.

Optimizing DC Vaccination by Combination With Oncolytic Adenovirus Coexpressing IL-12 and GM-CSF

Dendritic cell (DC)-based vaccination is a promising strategy for cancer immunotherapy. However, clinical trials have indicated that immunosuppressive microenvironments induced by tumors profoundly suppress antitumor immunity and inhibit vaccine efficacy, resulting in insufficient reduction of tumor burdens. To overcome these obstacles and enhance the efficiency of DC vaccination, we generated interleukin (IL)-12- and granulocyte-macrophage colony-stimulating factor (GM-CSF)-coexpressing oncolytic adenovirus (Ad-ΔB7/IL12/GMCSF) as suitable therapeutic adjuvant to eliminate immune suppression and promote DC function. By treating tumors with Ad-ΔB7/IL12/GMCSF prior to DC vaccination, DCs elicited greater antitumor effects than in response to either treatment alone. DC migration to draining lymph nodes (DLNs) dramatically increased in mice treated with the combination therapy. This result was associated with upregulation of CC-chemokine ligand 21 (CCL21+) lymphatics in tumors treated with Ad-ΔB7/IL12/GMCSF. Moreover, the proportion of CD4+CD25+ T-cells and vascular endothelial growth factor (VEGF) expression was decreased in mice treated with the combination therapy. Furthermore, combination therapy using immature DCs also showed effective antitumor effects when combined with Ad-ΔB7/IL12/GMCSF. The combination therapy had a remarkable therapeutic efficacy on large tumors. Taken together, oncolytic adenovirus coexpressing IL-12 and GM-CSF in combination with DC vaccination has synergistic antitumor effects and can act as a potent adjuvant for promoting and optimizing DC vaccination

A Novel sLRP6E1E2 Inhibits Canonical Wnt Signaling, Epithelial-to-Mesenchymal Transition, and Induces Mitochondria-Dependent Apoptosis in Lung Cancer

Aberrant activation of the Wnt pathway contributes to human cancer progression. Antagonists that interfere with Wnt ligand/receptor interactions can be useful in cancer treatments. In this study, we evaluated the therapeutic potential of a soluble Wnt receptor decoy in cancer gene therapy. We designed a Wnt antagonist sLRP6E1E2, and generated a replication-incompetent adenovirus (Ad), dE1-k35/sLRP6E1E2, and a replication-competent oncolytic Ad, RdB-k35/sLRP6E1E2, both expressing sLRP6E1E2. sLRP6E1E2 prevented Wnt-mediated stabilization of cytoplasmic β-catenin, decreased Wnt/β-catenin signaling and cell proliferation via the mitogen-activated protein kinase, and phosphatidylinositol 3-kinase pathways. sLRP6E1E2 induced apoptosis, cytochrome c release, and increased cleavage of PARP and caspase-3. sLRP6E1E2 suppressed growth of the human lung tumor xenograft, and reduced motility and invasion of cancer cells. In addition, sLRP6E1E2 upregulated expression of epithelial marker genes, while sLRP6E1E2 downregulated mesenchymal marker genes. Taken together, sLRP6E1E2, by inhibiting interaction between Wnt and its receptor, suppressed Wnt-induced cell proliferation and epithelial-to-mesenchymal transition

Imaging of Viral Thymidine Kinase Gene Expression by Replicating Oncolytic Adenovirus and Prediction of Therapeutic Efficacy

PURPOSE: We have used a genetically attenuated adenoviral vector which expresses HSVtk to assess the possible additive role of suicidal gene therapy for enhanced oncolytic effect of the virus. Expression of TK was measured using a radiotracer-based molecular counting and imaging system. MATERIALS AND METHODS: Replication-competent recombinant adenoviral vector (Ad-DeltaE1B19/55) was used in this study, whereas replication-incompetent adenovirus (Ad-DeltaE1A) was generated as a control. Both Ad-DeltaE1B19/55-TK and Ad-DeltaE1A-TK comprise the HSVtk gene inserted into the E3 region of the viruses. YCC-2 cells were infected with the viruses and incubated with 2'-deoxy-2'-fluoro-beta-D-arabinofuranosyl-5-iodouracil (I-131 FIAU) to measure amount of radioactivity. The cytotoxicity of the viruses was determined, and gamma ray imaging of HSVtk gene was performed. MTT assay was also performed after GCV treatment. RESULTS: On gamma counter-analyses, counts/ minute (cpm)/microg of protein showed MOIs dependency with DeltaE1B19/55-TK infection. On MTT assay, Ad-DeltaE1B19/55-TK led to more efficient cell killing than Ad-DeltaE1A-TK. On plate imaging by gamma camera, both Ad-DeltaE1B19/55-TK and Ad-DeltaE1A-TK infected cells showed increased I-131 FIAU uptake in a MOI dependent pattern, and with GCV treatment, cell viability of DeltaE1B19/55-TK infection was remarkably reduced compared to that of Ad-DeltaE1A-TK infection. CONCLUSION: Replicating Ad-DeltaE1B19/55-TK showed more efficient TK expression even in the presence of higher-cancer cell killing effects compared to non-replicating Ad-DeltaE1A-TK. Therefore, GCV treatment still possessed an additive role to oncolytic effect of Ad-DeltaE1B19/55-TK. The expression of TK by oncolytic viruses could rapidly be screened using a radiotracer-based counting and imaging technique.ope

Identification and Functional Characterization of Anti-metastasis and Anti-angiogenic Activities of Triethylene Glycol Derivatives

We had previously reported anticancer activity in the water extract (WEX) of Ashwagandha leaves, and identified Triethylene glycol (TEG) as an active tumor suppressor component. In this study, we investigated anti-migratory and anti-angiogenesis activities of WEX and TEG. We conducted in vitro and in vivo experiments using TEG, and its two derivatives, Triethyleneglycol dimethacrylate (TD-10), and Tetraethyleneglycol dimethacrylate (TD-11). The data revealed strong anticancer and anti-metastasis potentials in the derivatives. Non-toxic, anti-migratory doses of the derivatives showed inhibition of canonical Wnt/β-catenin axis and consequent downregulation of EMT-signaling proteins (Vimentin, MMPs and VEGF). These results endorse that the TD-10 and TD-11 have potential to safely put a check on the aggressiveness of the metastatic cells and therefore represent promising candidates for the treatment of metastatic cancers