Inhibition of human diffuse large B-cell lymphoma growth by JC polyomavirus-like particles delivering a suicide gene

Virus-inspired strategies for cancer therapy

The intentional use of viruses for cancer therapy dates back over a century. As viruses are inherently immunogenic and naturally optimized delivery vehicles, repurposing viruses for drug delivery, tumor antigen presentation, or selective replication in cancer cells represents a simple and elegant approach to cancer treatment. While early virotherapy was fraught with harsh side effects and low response rates, virus-based therapies have recently seen a resurgence due to newfound abilities to engineer and tune oncolytic viruses, virus-like particles, and virus-mimicking nanoparticles for improved safety and efficacy. However, despite their great potential, very few virus-based therapies have made it through clinical trials. In this review, we present an overview of virus-inspired approaches for cancer therapy, discuss engineering strategies to enhance their mechanisms of action, and highlight their application for overcoming the challenges of traditional cancer therapies.

Suppression of bone metastatic castration-resistant prostate cancer cell growth by a suicide gene delivered by JC polyomavirus-like particles

Prostate cancer is one of the most common cancers in men. The heterogeneity and mutations exhibited by prostate cancer cells often results in the progression to incurable metastatic castration-resistant prostate cancer (mCRPC). Our previous investigations demonstrated that the virus-like particles (VLPs) of JC polyomavirus (JCPyV) can deliver exogenous genes to prostate cancer cells for expression. JCPyV VLPs packaging pPSAtk (PSAtk-VLPs) possess the ability to transcriptionally target and selectively induce cytotoxicity in prostate cancer cells in vitro and in vivo, as pPSAtk can only express the thymidine kinase gene, a suicide gene, in androgen receptor-positive cells. To further investigate whether PSAtk-VLPs inhibit the growth of metastasized prostate cancer cells, we established an animal model of bone-metastatic prostate cancer to compare PSAtk-VLPs with leuprorelin acetate and enzalutamide, hormonal agents commonly used in clinical settings, and investigated the effectiveness of PSAtk-VLPs. In the present study, we observed that PSAtk-VLPs effectively inhibited the growth of prostate cancer cells that had metastasized to the bone in the metastatic animal model. In addition, PSAtk-VLPs showed a higher effectiveness than hormone therapy in this animal model study. These results suggest that PSAtk-VLPs may serve as a treatment option for mCRPC therapy in the future.

Peptide-guided JC polyomavirus-like particles specifically target bladder cancer cells for gene therapy

The ultimate goal of gene delivery vectors is to establish specific and effective treatments for human diseases. We previously demonstrated that human JC polyomavirus (JCPyV) virus-like particles (VLPs) can package and deliver exogenous DNA into susceptible cells for gene expression. For tissue-specific targeting in this study, JCPyV VLPs were conjugated with a specific peptide for bladder cancer (SPB) that specifically binds to bladder cancer cells. The suicide gene thymidine kinase was packaged and delivered by SPB-conjugated VLPs (VLP-SPBs). Expression of the suicide gene was detected only in human bladder cancer cells and not in lung cancer or neuroblastoma cells susceptible to JCPyV VLP infection in vitro and in vivo, demonstrating the target specificity of VLP-SPBs. The gene transduction efficiency of VLP-SPBs was approximately 100 times greater than that of VLPs without the conjugated peptide. JCPyV VLPs can be specifically guided to target particular cell types when tagged with a ligand molecule that binds to a cell surface marker, thereby improving gene therapy.

Bile Acid Conjugates with Anticancer Activity: Most Recent Research

The advantages of a treatment modality that combines two or more therapeutic agents in cancer therapy encourages the study of hybrid functional compounds for pharmacological applications. In light of this, we reviewed recent works on hybrid molecules based on bile acids. Due to their biological properties, as well as their different chemical/biochemical reactive moieties, bile acids can be considered very interesting starting molecules for conjugation with natural or synthetic bioactive molecules.

Inhibition of human lung adenocarcinoma growth and metastasis by JC polyomavirus-like particles packaged with an SP-B promoter-driven CD59-specific shRNA

Lung cancer ranks first in both incidence and mortality and is a major health concern worldwide. Upon recognition of specific antigens on tumor cells, complement-dependent cytotoxicity (CDC) is activated, arresting cell growth or inducing apoptosis. However, by overexpressing CD59, a membrane complement regulatory protein (mCRP), lung cancer cells develop resistance to CDC. We previously showed that virus-like particles (VLPs) of human JC polyomavirus (JCPyV) could be used as a gene therapy vector to carry a suicide gene expression plasmid with a lung-specific promoter (SP-B (surfactant protein B)) for lung adenocarcinomas. Herein, we designed a CD59-specific short hairpin RNA (shRNA) expression plasmid driven by SP-B (pSPB-shCD59) to effectively and specifically inhibit CD59 overexpression in lung cancer cells. Treatment of lung cancer cells in vitro with JCPyV VLPs containing pSPB-shCD59 (pSPB-shCD59/VLPs) induces CDC and death of cancer cells. Mice that were subcutaneously injected with human lung cancer cells showed an 87% inhibition in tumor growth after tail vein injection of pSPB-shCD59/VLPs. Moreover, in a mouse model of lung cancer metastasis, a reduction in the lung weight by 39%, compared with the control group, was observed in mice treated with pSPB-shCD59/VLPs after tail vein injection of human lung cancer cells. Furthermore, tissue sectioning showed that the number and size of tumors produced was significantly reduced in the lungs of mice in the treatment group than those of the untreated group, indicating inhibition of metastasis by pSPB-shCD59/VLPs. Together, these results demonstrate the potential of pSPB-shCD59/VLPs as a therapeutic agent for CD59 overexpressed lung cancer.

The biomedical and bioengineering potential of protein nanocompartments

Protein nanocompartments (PNCs) are self-assembling biological nanocages that can be harnessed as platforms for a wide range of nanobiotechnology applications. The most widely studied examples of PNCs include virus-like particles, bacterial microcompartments, encapsulin nanocompartments, enzyme-derived nanocages (such as lumazine synthase and the E2 component of the pyruvate dehydrogenase complex), ferritins and ferritin homologues, small heat shock proteins, and vault ribonucleoproteins. Structural PNC shell proteins are stable, biocompatible, and tolerant of both interior and exterior chemical or genetic functionalization for use as vaccines, therapeutic delivery vehicles, medical imaging aids, bioreactors, biological control agents, emulsion stabilizers, or scaffolds for biomimetic materials synthesis. This review provides an overview of the recent biomedical and bioengineering advances achieved with PNCs with a particular focus on recombinant PNC derivatives.

Human Polyomavirus JCPyV and Its Role in Progressive Multifocal Leukoencephalopathy and Oncogenesis

The human neurotropic virus JCPyV, a member of the Polyomaviridiae family, is the opportunistic infectious agent of Progressive Multifocal Leukoencephalopathy (PML), a fatal disease seen in severe immunosuppressive conditions and, during the last decade, in patients undergoing immunotherapy. JCPyV is a ubiquitous pathogen with up to 85% of the adult population word-wide exhibiting antibodies against it. Early experiments demonstrated that direct inoculation of JCPyV into the brain of different species resulted in the development of brain tumors and other neuroectodermal-derived neoplasias. Later, several reports showed the detection of viral sequences in medulloblastomas and glial tumors, as well as expression of the viral protein T-Antigen. Few oncogenic viruses, however, have caused so much controversy regarding their role in the pathogenesis of brain tumors, but the discovery of new Polyomaviruses that cause Merkel cell carcinomas in humans and brain tumors in racoons, in addition to the role of JCPyV in colon cancer and multiple mechanistic studies have shed much needed light on the role of JCPyV in cancer. The pathways affected by the viral protein T-Antigen include cell cycle regulators, like p53 and pRb, and transcription factors that activate pro-proliferative genes, like c-Myc. In addition, infection with JCPyV causes chromosomal damage and T-Antigen inhibits homologous recombination, and activates anti-apoptotic proteins, such as Survivin. Here we review the different aspects of the biology and physiopathology of JCPyV.

Synthetic Approaches for Nucleic Acid Delivery: Choosing the Right Carriers

The discovery of the genetic roots of various human diseases has motivated the exploration of different exogenous nucleic acids as therapeutic agents to treat these genetic disorders (inherited or acquired). However, the physicochemical properties of nucleic acids render them liable to degradation and also restrict their cellular entrance and gene translation/inhibition at the correct cellular location. Therefore, gene condensation/protection and guided intracellular trafficking are necessary for exogenous nucleic acids to function inside cells. Diversified cationic formulation materials, including natural and synthetic lipids, polymers, and proteins/peptides, have been developed to facilitate the intracellular transportation of exogenous nucleic acids. The chemical properties of different formulation materials determine their special features for nucleic acid delivery, so understanding the property-function correlation of the formulation materials will inspire the development of next-generation gene delivery carriers. Therefore, in this review, we focus on the chemical properties of different types of formulation materials and discuss how these formulation materials function as protectors and cellular pathfinders for nucleic acids, bringing them to their destination by overcoming different cellular barriers.

Gene therapy for human glioblastoma using neurotropic JC virus-like particles as a gene delivery vector

Glioblastoma multiforme (GBM), the most common malignant brain tumor, has a short period of survival even with recent multimodality treatment. The neurotropic JC polyomavirus (JCPyV) infects glial cells and oligodendrocytes and causes fatal progressive multifocal leukoencephalopathy in patients with AIDS. In this study, a possible gene therapy strategy for GBM using JCPyV virus-like particles (VLPs) as a gene delivery vector was investigated. We found that JCPyV VLPs were able to deliver the GFP reporter gene into tumor cells (U87-MG) for expression. In an orthotopic xenograft model, nude mice implanted with U87 cells expressing the near-infrared fluorescent protein and then treated by intratumoral injection of JCPyV VLPs carrying the thymidine kinase suicide gene, combined with ganciclovir administration, exhibited significantly prolonged survival and less tumor fluorescence during the experiment compared with controls. Furthermore, JCPyV VLPs were able to protect and deliver a suicide gene to distal subcutaneously implanted U87 cells in nude mice via blood circulation and inhibit tumor growth. These findings show that metastatic brain tumors can be targeted by JCPyV VLPs carrying a therapeutic gene, thus demonstrating the potential of JCPyV VLPs to serve as a gene therapy vector for the far highly treatment-refractory GBM.

Administration of co-expressed Penaeus stylirostris densovirus-like particles and dsRNA-YHV-Pro provide protection against yellow head virus in shrimp

The activation of the innate RNA interference pathway through double-stranded RNAs (dsRNAs) is one of the approaches to protecting shrimp from viruses. Previous studies have shown that injection of specific dsRNAs can successfully inhibit viral infection in shrimp. However, inhibition requires high levels of dsRNA and dsRNA stability in shrimp is limited. Virus-like particles (VLPs) have been applied to deliver nucleic acids into host cells because of the protection of dsRNAs from host endonucleases as well as the target specificity provided by VLPs. Therefore, this study aimed to develop Penaeus stylirostris densovirus (PstDNV) VLPs for dsRNA deliver to shrimp. The PstDNV capsid protein was expressed and can be self-assembled to form PstDNV VLPs. Co-expression of dsRNA-YHV-Pro and PstDNV capsid protein was achieved in the same bacterial cells, whose structure was displayed as the aggregation of VLPs by TEM. Tested for their inhibiting yellow head virus (YHV) from infecting shrimp, the dsRNA-YHV-Pro-PstDNV VLPs gave higher levels of YHV suppression and a greater reduction in shrimp mortality than the delivery of naked dsRNA-YHV-Pro. Therefore, PstDNV-VLPs are a promising vehicle for dsRNA delivery that maintains the anti-virus activity of dsRNA in shrimp over a longer period of time as compared to native dsRNAs.