Transmorphic phage-guided systemic delivery of TNFα gene for the treatment of human pediatric medulloblastoma.

Medulloblastoma is the most common childhood brain tumor with an unfavorable prognosis and limited options of harmful treatments that are associated with devastating long-term side effects. Therefore, the development of safe, noninvasive, and effective therapeutic approaches is required to save the quality of life of young medulloblastoma survivors. We postulated that therapeutic targeting is a solution. Thus, we used a recently designed tumor-targeted bacteriophage (phage)-derived particle, named transmorphic phage/AAV, TPA, to deliver a transgene expressing the tumor necrosis factor-alpha (TNFα) for targeted systemic therapy of medulloblastoma. This vector was engineered to display the double-cyclic RGD4C ligand to selectively target tumors after intravenous administration. Furthermore, the lack of native phage tropism in mammalian cells warrants safe and selective systemic delivery to the tumor microenvironment. In vitro RGD4C.TPA.TNFα treatment of human medulloblastoma cells generated efficient and selective TNFα expression, subsequently triggering cell death. Combination with the chemotherapeutic drug cisplatin used clinically against medulloblastoma resulted in augmented effect through the enhancement of TNFα gene expression. Systemic administration of RGD4C.TPA.TNFα to mice-bearing subcutaneous medulloblastoma xenografts resulted in selective tumor homing of these particles and consequently, targeted tumor expression of TNFα, apoptosis, and destruction of the tumor vasculature. Thus, our RGD4C.TPA.TNFα particle provides selective and efficient systemic delivery of TNFα to medulloblastoma, yielding a potential TNFα anti-medulloblastoma therapy while sparing healthy tissues from the systemic toxicity of this cytokine.

Systemically targeted cancer immunotherapy and gene delivery using transmorphic particles.

Immunotherapy is a powerful tool for cancer treatment, but the pleiotropic nature of cytokines and immunological agents strongly limits clinical translation and safety. To address this unmet need, we designed and characterised a systemically targeted cytokine gene delivery system through transmorphic encapsidation of human recombinant adeno-associated virus DNA using coat proteins from a tumour-targeted bacteriophage (phage). We show that Transmorphic Phage/AAV (TPA) particles provide superior delivery of transgenes over current phage-derived vectors through greater diffusion across the extracellular space and improved intracellular trafficking. We used TPA to target the delivery of cytokine-encoding transgenes for interleukin-12 (IL12), and novel isoforms of IL15 and tumour necrosis factor alpha (TNF α ) for tumour immunotherapy. Our results demonstrate selective and efficient gene delivery and immunotherapy against solid tumours in vivo, without harming healthy organs. Our transmorphic particle system provides a promising modality for safe and effective gene delivery, and cancer immunotherapies through cross-species complementation of two commonly used viruses.

Bacteriophage-mediated therapy of chondrosarcoma by selective delivery of the tumor necrosis factor alpha (TNFα) gene.

Chondrosarcoma is a cartilage-forming bone tumor, well known for intrinsic resistance to chemotherapy and radiotherapy. We have designed a targeted chondrosarcoma gene therapy using a bacteriophage (phage) particle to deliver therapeutic genes. Phage has no tropism for mammalian cells, allowing engineered phage to be targeted to specific cell surface receptors in cancer. We modified the phage capsid to display the RGD4C ligand on the pIII minor coat proteins to specifically bind to αvß3 or αvß5 integrin receptors. The endosomal escape peptide, H5WYG, was also displayed on recombinant pVIII major coat proteins to enhance gene delivery. Finally, a human tumor necrosis factor alpha (TNFα) therapeutic transgene expression cassette was incorporated into the phage genome. First, we found that human chondrosarcoma cells (SW1353) have high expression of αvß3, αvß5 integrin receptors, and both TNFα receptors. Targeted particle encoding a luciferase reporter gene efficiently and selectively mediated gene delivery to these cells. When SW1353 cells were treated with the targeted particle encoding a TNFα transgene, significant cell killing was evident and was associated with high expression of TNFα and apoptosis-related genes. In vivo, mice with established human chondrosarcoma showed suppression of tumors upon repetitive intravenous administrations of the targeted phage. These data show that our phage-based particle is a promising, selective, and efficient tool for targeted chondrosarcoma therapy.

Pacemaker implantation post congenital heart disease surgical repair: tertiary center experience.

This was a retrospective study documenting all pacemaker implantations (PMIs) secondary to postoperative atrioventricular block. A total of 26 patients were included between 2011 and 2020. The incidence rate was 1.8%, with a median follow-up time of 4.5 years. At the time of the initial PMI, the median weight was 5 kg, and the median generator longevity was 45 months. Mean cardiopulmonary bypass and aortic clamp times were significantly longer among surgeries complicated with PMI (P≤ 0.05). Trisomy 21 patients were 4 times more likely to need a PMI (95% CI 1.8-9, P < 0.001). The mean Risk Adjustment in Congenital Heart Surgery and Society of Thoracic Surgery scores were higher in patients with PMI. All initial PMIs were epicardial (18 single chamber). Most patients underwent ventricular septal defect closure (isolated or complex), except for 5 patients who underwent left-sided surgery. Pacing-induced dilated cardiomyopathy occurred in 3 patients. All implanted leads were functional except for 2 leads with high thresholds and another biventricular system infection. There was a 31% rate of pacing reintervention.Conclusion: PMI resulted in significant morbidity but without mortality. The highest risk for PMI was left ventricular outflow tract repair, trisomy 21, prolonged cardiopulmonary bypass, and aortic cross times. What is Known: •Incidence rate for postoperative atrioventricular block requiring pacemaker was at 1.8%, similar to previously published reports. •Longer cardiopulmonary bypass and aortic cross-clamp times were associated with higher risk for developing postoperative persistent atrioventricular block. What is New: •Incidence for persistent atrioventricular block requiring pacemaker was highest among left ventricular outflow tract surgery at 8.6%. •Following all intracardiac repair, Down syndrome patients were 4 times more likely to need a pacemaker implantation compared to the non-syndromic group.

The natural dietary genistein boosts bacteriophage-mediated cancer cell killing by improving phage-targeted tumor cell transduction.

Gene therapy has long been regarded as a promising treatment for cancer. However, cancer gene therapy is still facing the challenge of targeting gene delivery vectors specifically to tumors when administered via clinically acceptable non-invasive systemic routes (i.e. intravenous). The bacteria virus, bacteriophage (phage), represents a new generation of promising vectors in systemic gene delivery since their targeting can be achieved through phage capsid display ligands, which enable them to home to specific tumor receptors without the need to ablate any native eukaryotic tropism. We have previously reported a tumor specific bacteriophage vector named adeno-associated virus/phage, or AAVP, in which gene expression is under a recombinant human rAAV2 virus genome targeted to tumors via a ligand-directed phage capsid. However, cancer gene therapy with this tumor-targeted vector achieved variable outcomes ranging from tumor regression to no effect in both experimental and natural preclinical models. Herein, we hypothesized that combining the natural dietary genistein, with proven anticancer activity, would improve bacteriophage anticancer safe therapy. We show that combination treatment with genistein and AAVP increased targeted cancer cell killing by AAVP carrying the gene for Herpes simplex virus thymidine kinase (HSVtk) in 2D tissue cultures and 3D tumor spheroids. We found this increased tumor cell killing was associated with enhanced AAVP-mediated gene expression. Next, we established that genistein protects AAVP against proteasome degradation and enhances vector genome accumulation in the nucleus. Combination of genistein and phage-guided virotherapy is a safe and promising strategy that should be considered in anticancer therapy with AAVP.