CXCL12-targeted immunomodulatory gene therapy reduces radiation-induced fibrosis in healthy tissues.

Radiation-induced fibrosis (RIF) is a progressive pathology deleteriously impacting cancer survivorship. CXCL12 is an immune-stromal signal implicated in fibrosis and innate response. We hypothesised that modulation of CXCL12 would phenotypically mitigate RIF.

Combination of oncolytic Maraba virus with immune checkpoint blockade overcomes therapy resistance in an immunologically cold model of advanced melanoma with dysfunctional T-cell receptor signalling.

Background: Over the past decade, cancer immunotherapies have revolutionized the treatment of melanoma; however, responses vary across patient populations. Recently, baseline tumor size has been identified as an independent prognostic factor for overall survival in patients with melanoma receiving immune checkpoint inhibitors. MG1 is a novel oncolytic agent with broad tumor tropism that has recently entered early-phase clinical trials.

A RIPK1-specific PROTAC degrader achieves potent antitumor activity by enhancing immunogenic cell death.

Receptor-interacting serine/threonine-protein kinase 1 (RIPK1) functions as a critical stress sentinel that coordinates cell survival, inflammation, and immunogenic cell death (ICD). Although the catalytic function of RIPK1 is required to trigger cell death, its non-catalytic scaffold function mediates strong pro-survival signaling. Accordingly, cancer cells can hijack RIPK1 to block necroptosis and evade immune detection.

CD4 T cell dynamics shape the immune response to combination oncolytic herpes virus and BRAF inhibitor therapy for melanoma.

Background: Combination herpes simplex virus (HSV) oncolytic virotherapy and BRAF inhibitors (BRAFi) represent promising immunogenic treatments for BRAF mutant melanoma, but an improved understanding of the immunobiology of combinations is needed to improve on the benefit of immune checkpoint inhibitors (ICI).

Methods: Using a BRAF-driven murine melanoma model, we tested the immunogenicity of HSV/BRAFi in immunocompetent C57BL mice. In addition to standard FACS analysis, we used the 'Timer of Cell Kinetics and Activity' system, which can analyze the temporal dynamics of different T cell subsets.

RIPK1-mediated immunogenic cell death promotes anti-tumour immunity against soft-tissue sarcoma.

Drugs that mobilise the immune system against cancer are dramatically improving care for many people. Dying cancer cells play an active role in inducing anti-tumour immunity but not every form of death can elicit an immune response. Moreover, resistance to apoptosis is a major problem in cancer treatment and disease control.

The PERK Inhibitor GSK2606414 Enhances Reovirus Infection in Head and Neck Squamous Cell Carcinoma via an ATF4-Dependent Mechanism.

Reovirus type 3 Dearing (reovirus) is a tumor-selective oncolytic virus currently under evaluation in clinical trials. Here, we report that the therapeutic efficacy of reovirus in head and neck squamous cell cancer can be enhanced by targeting the unfolded protein response (UPR) kinase, protein kinase R (PKR)-like endoplasmic reticulum kinase (PERK). PERK inhibition by GSK2606414 increased reovirus efficacy in both 2D and 3D models , while perturbing the normal host cell response to reovirus-induced endoplasmic reticulum (ER) stress.

Combination therapy with oncolytic viruses and immune checkpoint inhibitors.

: Immune checkpoint inhibitors (ICI) have dramatically improved the outcome for cancer patients across multiple tumor types. However the response rates to ICI monotherapy remain relatively low, in part due to some tumors cultivating an inherently 'cold' immune microenvironment. Oncolytic viruses (OV) have the capability to promote a 'hotter' immune microenvironment which can improve the efficacy of ICI.

Development of a new fusion-enhanced oncolytic immunotherapy platform based on herpes simplex virus type 1.

Background: Oncolytic viruses preferentially replicate in tumors as compared to normal tissue and promote immunogenic cell death and induction of host systemic anti-tumor immunity. HSV-1 was chosen for further development as an oncolytic immunotherapy in this study as it is highly lytic, infects human tumor cells broadly, kills mainly by necrosis and is a potent activator of both innate and adaptive immunity. HSV-1 also has a large capacity for the insertion of additional, potentially therapeutic, exogenous genes.

PD-1 Blockade Following Isolated Limb Perfusion with Vaccinia Virus Prevents Local and Distant Relapse of Soft-tissue Sarcoma.

Purpose: The prevention and treatment of metastatic sarcoma are areas of significant unmet need. Immune checkpoint inhibitor monotherapy has shown little activity in sarcoma and there is great interest in identifying novel treatment combinations that may augment responses. and , we investigated the potential for an oncolytic vaccinia virus (GLV-1h68) delivered using isolated limb perfusion (ILP) to promote antitumor immune responses and augment response to PD-1 blockade in sarcoma.

Synergistic antitumour effects of rapamycin and oncolytic reovirus.

There are currently numerous oncolytic viruses undergoing clinical trial evaluation in cancer patients and one agent, Talimogene laherparepvec, has been approved for the treatment of malignant melanoma. This progress highlights the huge clinical potential of this treatment modality, and the focus is now combining these agents with conventional anticancer treatments or agents that enhance viral replication, and thereby oncolysis, in the tumour microenvironment. We evaluated the combination of reovirus with rapamycin in B16F10 cell, a murine model of malignant melanoma, based on potential mechanisms by which mTOR inhibitors might enhance viral oncolysis.

Genetically modified lentiviruses that preserve microvascular function protect against late radiation damage in normal tissues.

Improvements in cancer survival mean that long-term toxicities, which contribute to the morbidity of cancer survivorship, are being increasingly recognized. Late adverse effects (LAEs) in normal tissues after radiotherapy (RT) are characterized by vascular dysfunction and fibrosis causing volume loss and tissue contracture, for example, in the free flaps used for immediate breast reconstruction after mastectomy. We evaluated the efficacy of lentivirally delivered superoxide dismutase 2 (SOD2) overexpression and connective tissue growth factor (CTGF) knockdown by short hairpin RNA in reducing the severity of LAEs in an animal model of free flap LAEs.

Oncolytic vaccinia virus combined with radiotherapy induces apoptotic cell death in sarcoma cells by down-regulating the inhibitors of apoptosis.

Advanced extremity melanoma and sarcoma present a significant therapeutic challenge, requiring multimodality therapy to treat or even palliate disease. These aggressive tumours are relatively chemo-resistant, therefore new treatment approaches are urgently required. We have previously reported on the efficacy of oncolytic virotherapy (OV) delivered by isolated limb perfusion.

Enhanced cytotoxicity of reovirus and radiotherapy in melanoma cells is mediated through increased viral replication and mitochondrial apoptotic signalling.

Oncolytic viruses selectively target and replicate in cancer cells, providing us with a unique tool with which to target and kill tumour cells. These viruses come from a diverse range of viral families including reovirus type 3 Dearing (RT3D), a non-pathogenic human double-stranded RNA oncolytic virus, which has been shown to be an effective therapeutic agent, both as a mono-therapy and in combination with traditional chemotherapeutic drugs. This study investigated the interaction between RT3D and radiotherapy in melanoma cell lines with a BRAF mutant, Ras mutant or BRAF/Ras wild type genotype.

Isolated limb perfusion with biochemotherapy and oncolytic virotherapy combines with radiotherapy and surgery to overcome treatment resistance in an animal model of extremity soft tissue sarcoma.

The management of locally advanced or recurrent extremity sarcoma often necessitates multimodal therapy to preserve a limb, of which isolated limb perfusion (ILP) is a key component. However, with standard chemotherapeutic agents used in ILP, the duration of response is limited. Novel agents or treatment combinations are urgently needed to improve outcomes.

Trametinib radiosensitises RAS- and BRAF-mutated melanoma by perturbing cell cycle and inducing senescence.

Purpose: Radiotherapy (RT) is used frequently in patients with melanoma, but results are suboptimal because the disease is often radioresistant. This may be due to constitutive activation of MAPK pathway signalling through mutations involving RAS/RAF. Thus, we studied whether trametinib, a potent and selective allosteric inhibitor of MEK1/2 could improve the efficacy of RT.

BRAF- and MEK-Targeted Small Molecule Inhibitors Exert Enhanced Antimelanoma Effects in Combination With Oncolytic Reovirus Through ER Stress.

Reovirus type 3 (Dearing) (RT3D) infection is selective for cells harboring a mutated/activated RAS pathway. Therefore, in a panel of melanoma cell lines (including RAS mutant, BRAF mutant and RAS/BRAF wild-type), we assessed therapeutic combinations that enhance/suppress ERK1/2 signaling through use of BRAF/MEK inhibitors. In RAS mutant cells, the combination of RT3D with the BRAF inhibitor PLX4720 (paradoxically increasing ERK1/2 signaling in this context) did not enhance reoviral cytotoxicity.

Phase I trial of cyclophosphamide as an immune modulator for optimizing oncolytic reovirus delivery to solid tumors.

Purpose: Reovirus is a wild-type oncolytic virus that is ubiquitous in the environment; most patients are therefore preimmune. Therapeutic administration leads to an increase in neutralizing antireovirus antibody (NARA) titer. We hypothesized that if NARA limited reovirus antitumor activity, the effect might be attenuated by coadministration of cyclophosphamide.

Isolated limb perfusion with melphalan, tumour necrosis factor-alpha and oncolytic vaccinia virus improves tumour targeting and prolongs survival in a rat model of advanced extremity sarcoma.

Isolated limb perfusion (ILP) is a treatment for advanced extremity sarcoma and in-transit melanoma. Advancing this procedure by investigating the addition of novel agents, such as cancer-selective oncolytic viruses, may improve both the therapeutic efficacy of ILP and the tumour-targeted delivery of oncolytic virotherapy. Standard in vitro assays were used to characterise single agent and combinatorial activities of melphalan, tumour necrosis factor-alpha (TNF-α) and Lister strain vaccinia virus (GLV-1h68) against BN175 rat sarcoma cells.

Optimising measles virus-guided radiovirotherapy with external beam radiotherapy and specific checkpoint kinase 1 inhibition.

Background And Purpose: We previously reported a therapeutic strategy comprising replication-defective NIS-expressing adenovirus combined with radioiodide, external beam radiotherapy (EBRT) and DNA repair inhibition. We have now evaluated NIS-expressing oncolytic measles virus (MV-NIS) combined with NIS-guided radioiodide, EBRT and specific checkpoint kinase 1 (Chk1) inhibition in head and neck and colorectal models.

Materials And Methods: Anti-proliferative/cytotoxic effects of individual agents and their combinations were measured by MTS, clonogenic and Western analysis.

Oncolytic reovirus type 3 (Dearing) as a novel therapy in head and neck cancer.

Introduction: Locally advanced head and neck cancer carries a poor prognosis, even with standard combination (surgery, radiotherapy, chemotherapy) treatment regimens. There is a pressing need for novel therapies with activity against this tumour type. Oncolytic reovirus type 3 (Dearing) is preferentially cytotoxic in tumour cells with an activated Ras signalling pathway and represents a promising novel therapy with relevance in head and neck cancer.

Reovirus exerts potent oncolytic effects in head and neck cancer cell lines that are independent of signalling in the EGFR pathway.

Background: Reovirus exploits aberrant signalling downstream of Ras to mediate tumor-specific oncolysis. Since ~90% squamous cell carcinomas of the head and neck (SCCHN) over-express EGFR and SCCHN cell lines are sensitive to oncolytic reovirus, we conducted a detailed analysis of the effects of reovirus in 15 head and neck cancer cell lines. Both pre- and post-entry events were studied in an attempt to define biomarkers predictive of sensitivity/resistance to reovirus.

Phase II trial of intravenous administration of Reolysin(®) (Reovirus Serotype-3-dearing Strain) in patients with metastatic melanoma.

Reovirus, a replication competent RNA virus, has preclinical activity against melanoma lines and xenografts. We conducted a phase II trial of reovirus in metastatic melanoma patients. Patients received 3 × 10(10) TCID50 on days 1-5 of each 28 day cycle, administered intravenously.