Oncolytic Virotherapy

With the advancement of a growing number of oncolytic viruses (OVs) to clinical development, drug delivery is becoming an important barrier to overcome for optimal therapeutic benefits. Host immunity, tumor microenvironment and abnormal vascularity contribute to inefficient vector delivery. A number of novel approaches for enhanced OV delivery are under evaluation, including use of nanoparticles, immunomodulatory agents and complex viral-particle ligands along with manipulations of the tumor microenvironment...

BACKGROUND: HF10 is a highly attenuated type 1 herpes simplex virus (HSV) with proven effective oncolytic effect. Previous investigations have demonstrated that colon cancer mice model treated with HF10 not only had better survival but were also resistant to the reimplantation of the antitumor effect mediated by host antitumor immunity. Importantly, it has also been noted that in mice with antitumors implanted on both sides of the back, an injection of HF10 on only one side strongly restrains not only the injected antitumor but also the non-injected ones...

PURPOSE: To investigate the specific role of immune responses induced by lentogenic Newcastle disease virus (NDV) for its antitumor effect. MATERIALS AND METHODS: NDV LaSota strain was used to infect the following human cells: non-small cell lung carcinoma (A549), glioblastoma (U87MG and T98G), mammary gland adenocarcinoma (MCF7 and MDA-MB-453), hepatocellular carcinoma (Huh7), transformed embryonic kidney cells (HEK293), primary monocytes, lung fibroblast (HF19), skin fibroblast (NB1RGB) and rat astroglia (RCR-1) at 0...

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The treatment of metastatic melanoma has evolved from an era where interferon and chemotherapy were the mainstay of treatments to an era where immunotherapy has become the frontline. Ipilimumab (IgG1 CTLA-4 inhibitor), nivolumab (IgG4 PD-1 inhibitor), pembrolizumab (IgG4 PD-1 inhibitor) and nivolumab combined with ipilimumab have become first-line therapies in patients with metastatic melanoma. In addition, the high prevalence of BRAF mutations in melanoma has led to the discovery and approval of targeted molecules, such as vemurafenib (BRAF kinase inhibitor) and trametinib (MEK inhibitor), as they yielded improved responses and survival in malignant melanoma patients...

Oncolytic virotherapy is the use of replication-competent viruses to treat malignancies. The potential of oncolytic virotherapy as an approach to cancer therapy is based on historical evidence that certain viral infections can cause spontaneous remission of both hematologic and solid tumor malignancies. Oncolytic virotherapy may eliminate cancer cells through either direct oncolysis of infected tumor cells or indirect immune-mediated oncolysis of uninfected tumor cells. Recent advances in oncolytic virotherapy include the development of a wide variety of genetically attenuated RNA viruses with precise cellular tropism and the identification of cell-surface receptors that facilitate viral transfer to the tissue of interest...

Ad vectors are promising delivery vehicles for cancer therapeutic interventions. However, their application is limited by promiscuous tissue tropism and hepatotoxicity. This limitation can be avoided by altering the native tropism of Ads so that they can be redirected to the target cells through alternate cellular receptors. The CXCR4 chemokine receptor belongs to a large superfamily of G-protein-coupled receptors and is known to be upregulated in a wide variety of cancers, including breast cancer and melanoma...

On October 27, 2015, talimogene laherparepvec (T-VEC), a first in class intralesional oncolytic virotherapy, was granted the US Food and Drug Administration approval for the treatment of melanoma in the skin and lymph nodes. Its approval has added yet another therapeutic option to the growing list of effective therapies for melanoma. Though the Phase III OPTiM trial has demonstrated its efficacy as a single agent, the target patient population remains narrow. With numerous effective and tolerable treatments available for unresectable and metastatic melanoma, intralesional therapies such as T-VEC are still finding their niche...

Seneca Valley Virus isolate 001 (SVV-001) is an oncolytic RNA virus of the Picornaviridae family. It is also the first picornavirus discovered of the novel genus Senecavirus. SVV-001 replicates through an RNA intermediate, bypassing a DNA phase, and is unable to integrate into the host genome. SVV-001 was originally discovered as a contaminant in the cell culture of fetal retinoblasts and has since been identified as a potent oncolytic virus against tumors of neuroendocrine origin. SVV-001 has a number of features that make it an attractive oncolytic virus, namely, its ability to target and penetrate solid tumors via intravenous administration, inability for insertional mutagenesis, and being a self-replicating RNA virus with selective tropism for cancer cells...

Pediatric solid tumors remain a major health concern, with nearly 16,000 children diagnosed each year. Of those, ~2,000 succumb to their disease, and survivors often suffer from lifelong disability secondary to toxic effects of current treatments. Countless multimodality treatment regimens are being explored to make advances against this deadly disease. One targeted treatment approach is oncolytic virotherapy. Conditionally replicating viruses can infect tumor cells while leaving normal cells unharmed. Four viruses have been advanced to pediatric clinical trials, including herpes simplex virus-1, Seneca Valley virus, reovirus, and vaccinia virus...

Rhabdomyosarcoma (RMS) is a devastating tumor of young people that is difficult to cure. To determine if oncolytic virus therapy can improve outcomes in individuals with RMS, myxoma virus expressing a red fluorescent protein (MYXV-red) was evaluated for antitumoral effects using a murine model of RMS. Fluorescent protein was expressed in four RMS cell lines inoculated with MYXV-red, indicating that these cells were semipermissive to MYXV infection. MYXV-red replication and cytopathic effects were further evaluated using human embryonal RMS (CCL-136) cells...

Prostate cancer is a leading cause of cancer-related death and morbidity in men in the Western world. Tumor progression is dependent on functioning androgen receptor signaling, and initial administration of antiandrogens and hormone therapy (androgen-deprivation therapy) prevent growth and spread. Tumors frequently develop escape mechanisms to androgen-deprivation therapy and progress to castration-resistant late-stage metastatic disease that, in turn, inevitably leads to resistance to all current therapeutics, including chemotherapy...

Biomarkers associated with thyroid malignant neoplasm (TMN) have been widely applied in clinical diagnosis and in research oncological programs. The identification of novel TMN biomarkers has greatly improved the efficacy of clinical diagnosis. A more accurate diagnosis may lead to better clinical outcomes and effective treatments. However, the major deficiency of conventional chemotherapy and radiotherapy is lack of specificity. Due to the macrokinetic interactions, adverse side effects will occur, including chemotherapy and radiotherapy resistance...

Hematological malignancies are important diseases that need more powerful therapeutics. Even with current targeting therapies, such as rituximab and other chemotherapeutic agents, there is a need to develop new treatment strategies. Combination therapy seems the best option to target the tumor cells by different mechanisms. Virotherapy is a very promising treatment modality, as it is selective, safe, and causes cancer destruction. The Iraqi strain of Newcastle disease virus (NDV) has proved to be effective both in vitro and in vivo...

High-throughput screens can rapidly scan and capture large amounts of information across multiple biological parameters. Although many screens have been designed to uncover potential new therapeutic targets capable of crippling viruses that cause disease, there have been relatively few directed at improving the efficacy of viruses that are used to treat disease. Oncolytic viruses (OVs) are biotherapeutic agents with an inherent specificity for treating malignant disease. Certain OV platforms - including those based on herpes simplex virus, reovirus, and vaccinia virus - have shown success against solid tumors in advanced clinical trials...

Oncolytic viruses are multifunctional anticancer agents with huge clinical potential, and have recently passed the randomized Phase III clinical trial hurdle. Both wild-type and engineered viruses have been selected for targeting of specific cancers, to elicit cytotoxicity, and also to generate antitumor immunity. Single-agent oncolytic virotherapy treatments have resulted in modest effects in the clinic. There is increasing interest in their combination with cytotoxic agents, radiotherapy and immune-checkpoint inhibitors...

Oncolytic virotherapy exploits the properties of human viruses to naturally cytolysis of cancer cells. The human pathogen herpes simplex virus (HSV) has proven particularly amenable for use in oncolytic virotherapy. The relative safety of HSV coupled with extensive knowledge on how HSV interacts with the host has provided a platform for manipulating HSV to enhance the targeting and killing of human cancer cells. This has culminated in the approval of talimogene laherparepvec for the treatment of melanoma. This review focuses on the development of HSV as an oncolytic virus and where the field is likely to head in the future...

The field of ultrasound (US) has changed significantly from medical imaging and diagnosis to treatment strategies. US contrast agents or microbubbles (MB) are currently being used as potential carriers for chemodrugs, small molecules, nucleic acids, small interfering ribonucleic acid, proteins, adenoviruses, and oncolytic viruses. Oncolytic viruses can selectively replicate within and destroy a cancer cell, thus making them a powerful therapeutic in treating late-stage or metastatic cancer. These viruses have been shown to have robust activity in clinical trials when injected directly into tumor nodules...

Histone deacetylase (HDAC) enzymes play a critical role in the epigenetic regulation of cellular functions and signaling pathways in many cancers. HDAC inhibitors (HDACi) have been validated for single use or in combination with other drugs in oncologic therapeutics. An even more novel combination therapy with HDACi is to use them with an oncolytic virus. HDACi may lead to an amplification of tumor-specific lytic effects by facilitating increased cycles of viral replication, but there may also be direct anticancer effects of the drug by itself...

The oncolytic virotherapy field has made significant advances in the last decade, with a rapidly increasing number of early- and late-stage clinical trials, some of them showing safety and promising therapeutic efficacy. Targeting tumor vasculature by oncolytic viruses (OVs) is an attractive strategy that offers several advantages over nontargeted viruses, including improved tumor viral entry, direct antivascular effects, and enhanced antitumor efficacy. Current understanding of the biological mechanisms of tumor neovascularization, novel vascular targets, and mechanisms of resistance has allowed the development of oncolytic viral vectors designed to target tumor neovessels...