Perspectives on immunotherapy via oncolytic viruses

Current and future immunotherapeutic approaches in pancreatic cancer treatment

Pancreatic cancer is a major cause of cancer-related death, but despondently, the outlook and prognosis for this resistant type of tumor have remained grim for a long time. Currently, it is extremely challenging to prevent or detect it early enough for effective treatment because patients rarely exhibit symptoms and there are no reliable indicators for detection. Most patients have advanced or spreading cancer that is difficult to treat, and treatments like chemotherapy and radiotherapy can only slightly prolong their life by a few months. Immunotherapy has revolutionized the treatment of pancreatic cancer, yet its effectiveness is limited by the tumor's immunosuppressive and hard-to-reach microenvironment. First, this article explains the immunosuppressive microenvironment of pancreatic cancer and highlights a wide range of immunotherapy options, including therapies involving oncolytic viruses, modified T cells (T-cell receptor [TCR]-engineered and chimeric antigen receptor [CAR] T-cell therapy), CAR natural killer cell therapy, cytokine-induced killer cells, immune checkpoint inhibitors, immunomodulators, cancer vaccines, and strategies targeting myeloid cells in the context of contemporary knowledge and future trends. Lastly, it discusses the main challenges ahead of pancreatic cancer immunotherapy.

Enhancing oncolytic virus efficiency with methionine and N-(3-aminoprolil)methacrylamide modified acrylamide cationic block polymer

Oncolytic virus ablation of tumor cells has the advantages of high tumor selectivity, strong immunogenicity, and low side effects. However, the recognition and clearance of oncolytic viruses by the immune system are the main factors limiting their anti-tumor efficiency. As a highly biosafe and highly modifiable oncolytic virus vector, acrylamide can improve the long-term circulation of oncolytic viruses. Still, it is limited in its uptake efficiency by tumor cells. Herein, we constructed an N-hydroxymethyl acrylamide-b-(N-3-aminopropyl methacrylamide)-b-DMC block copolymer (NMA-b-APMA-b-DMA, NAD) as an oncolytic virus carrier, which not only improves the long-term circulation of oncolytic viruses in the body but also shows excellent stability for loading an oncolytic virus. The data shows that there was no obvious difference in the transfection effect of the NAD/Ad complex with or without neutralizing antibodies in the medium, which meant that the cationic carrier mediated by NAD/Ad had good serum stability. Only 10 micrograms of NAD carrier are needed to load the oncolytic virus, which can increase the transfection efficiency by 50 times. Cell experiments and mouse animal experiments show that NAD vectors can significantly enhance the anti-tumor effect of oncolytic viruses. We hope that this work will promote the application of acrylamide as an oncolytic virus vector and provide new ideas for methods to modify acrylamide for biomedical applications.

The tumor suppressive effect and apoptotic mechanism of TRAIL gene-containing recombinant NDV in TRAIL-resistant colorectal cancer HT-29 cells and TRAIL-nonresistant HCT116 cells, with each cell bearing a mouse model

BACKGROUND

TRAIL is an anticancer drug that induces cancer cell apoptosis by interacting with death receptors (DRs). However, owing to low cell-surface expression of DRs, certain colorectal cancer (CRC) cells resist TRAIL-induced apoptosis. Newcastle disease virus (NDV) infection can elevate DR protein expression in cancer cells, potentially influencing their TRAIL sensitivity. However, the precise mechanism by which NDV infection modulates DR expression and impacts TRAIL sensitivity in cancer cells remains unknown.

METHODS

Herein, we developed nonpathogenic NDV VG/GA strain-based recombinant NDV (rNDV) and TRAIL gene-containing rNDV (rNDV-TRAIL). We observed that viral infections lead to increased DR and TRAIL expressions and activate signaling proteins involved in intrinsic and extrinsic apoptosis pathways. Experiments were conducted in vitro using TRAIL-resistant CRC cells (HT-29) and nonresistant CRC cells (HCT116) and in vivo using relevant mouse models.

RESULTS

rNDV-TRAIL was found to exhibit better apoptotic efficacy than rNDV in CRC cells. Notably, rNDV-TRAIL had the stronger cancer cell-killing effect in TRAIL-resistant CRC cells. Western blot analyses showed that both rNDV and rNDV-TRAIL infections activate signaling proteins involved in the intrinsic and extrinsic apoptotic pathways. Notably, rNDV-TRAIL promotes concurrent intrinsic and extrinsic signal transduction in both HCT-116 and HT-29 cells.

CONCLUSIONS

Therefore, rNDV-TRAIL infection effectively enhances DR expression in DR-depressed HT-29 cells. Moreover, the TRAIL protein expressed by rNDV-TRAIL effectively interacts with DR, leading to enhanced apoptosis in TRAIL-resistant HT-29 cells. Therefore, rNDV-TRAIL has potential as a promising therapeutic approach for treating TRAIL-resistant cancers.

Human Monocytes Are Suitable Carriers for the Delivery of Oncolytic Herpes Simplex Virus Type 1 In Vitro and in a Chicken Embryo Chorioallantoic Membrane Model of Cancer

Oncolytic viruses (OVs) are promising therapeutics for tumors with a poor prognosis. An OV based on herpes simplex virus type 1 (oHSV-1), talimogene laherparepvec (T-VEC), has been recently approved by the Food and Drug Administration (FDA) and by the European Medicines Agency (EMA) for the treatment of unresectable melanoma. T-VEC, like most OVs, is administered via intratumoral injection, underlining the unresolved problem of the systemic delivery of the oncolytic agent for the treatment of metastases and deep-seated tumors. To address this drawback, cells with a tropism for tumors can be loaded ex vivo with OVs and used as carriers for systemic oncolytic virotherapy. Here, we evaluated human monocytes as carrier cells for a prototype oHSV-1 with a similar genetic backbone as T-VEC. Many tumors specifically recruit monocytes from the bloodstream, and autologous monocytes can be obtained from peripheral blood. We demonstrate here that oHSV-1-loaded primary human monocytes migrated in vitro towards epithelial cancer cells of different origin. Moreover, human monocytic leukemia cells selectively delivered oHSV-1 to human head-and-neck xenograft tumors grown on the chorioallantoic membrane (CAM) of fertilized chicken eggs after intravascular injection. Thus, our work shows that monocytes are promising carriers for the delivery of oHSV-1s in vivo, deserving further investigation in animal models.

Mesenchymal stem cell-released oncolytic virus: an innovative strategy for cancer treatment

Oncolytic viruses (OVs) infect, multiply, and finally remove tumor cells selectively, causing no damage to normal cells in the process. Because of their specific features, such as, the ability to induce immunogenic cell death and to contain curative transgenes in their genomes, OVs have attracted attention as candidates to be utilized in cooperation with immunotherapies for cancer treatment. This treatment takes advantage of most tumor cells' inherent tendency to be infected by certain OVs and both innate and adaptive immune responses are elicited by OV infection and oncolysis. OVs can also modulate tumor microenvironment and boost anti-tumor immune responses. Mesenchymal stem cells (MSC) are gathering interest as promising anti-cancer treatments with the ability to address a wide range of cancers. MSCs exhibit tumor-trophic migration characteristics, allowing them to be used as delivery vehicles for successful, targeted treatment of isolated tumors and metastatic malignancies. Preclinical and clinical research were reviewed in this study to discuss using MSC-released OVs as a novel method for the treatment of cancer. Video Abstract.

Oncolytic Viruses and Cancer Immunotherapy

PURPOSE OF REVIEW

Oncolytic viruses (OVs) exert their antitumor effect through selective killing of cancer cells and induction of host anti-tumor immunity. This review aims to summarize the recent and current trials with OVs for the treatment of lung cancer.

RECENT FINDINGS

Several OVs have been developed for the treatment of lung cancer including adenovirus, coxsackievirus B3, reovirus, and vaccinia virus and trials have demonstrated a safe toxicity profile. Early-phase trials in lung cancer with OVs have reported antiviral immune responses and evidence of clinical benefit. However, clinical efficacy of OVs in lung cancer either as monotherapy or in combination with chemotherapy has not been confirmed in larger phase II or III trials. Development of OVs in lung cancer has been limited by difficulty in administering OVs in the tumor directly as well as achieving adequate viral load at all tumor sites with systemically administered OVs. Developing novel combinations with OVs, especially checkpoint inhibitors and other immunotherapeutics, may be a strategy to address the limited success seen thus far. Integrating appropriate biomarker studies and meaningful endpoints in future clinical trials will be imperative. Using novel viral delivery systems in addition to increasing tumor specificity through improved genetic modifications in the OVs are other strategies to improve efficacy.

Comprehensive assessment on the applications of oncolytic viruses for cancer immunotherapy

The worldwide burden of cancers is increasing at a very high rate, including the aggressive and resistant forms of cancers. Certain levels of breakthrough have been achieved with the conventional treatment methods being used to treat different forms of cancers, but with some limitations. These limitations include hazardous side effects, destruction of non-tumor healthy cells that are rapidly dividing and developing, tumor resistance to anti-cancer drugs, damage to tissues and organs, and so on. However, oncolytic viruses have emerged as a worthwhile immunotherapeutic option for the treatment of different types of cancers. In this treatment approach, oncolytic viruses are being modeled to target cancer cells with optimum cytotoxicity and spare normal cells with optimal safety, without the oncolytic viruses themselves being killed by the host immune defense system. Oncolytic viral infection of the cancer cells are also being genetically manipulated (either by removal or addition of certain genes into the oncolytic virus genome) to make the tumor more visible and available for attack by the host immune cells. Hence, different variants of these viruses are being developed to optimize their antitumor effects. In this review, we examined how grave the burden of cancer is on a global level, particularly in sub-Saharan Africa, major conventional therapeutic approaches to the treatment of cancer and their individual drawbacks. We discussed the mechanisms of action employed by these oncolytic viruses and different viruses that have found their relevance in the fight against various forms of cancers. Some pre-clinical and clinical trials that involve oncolytic viruses in cancer management were reported. This review also examined the toxicity and safety concerns surrounding the adoption of oncolytic viro-immunotherapy for the treatment of cancers and the likely future directions for researchers and general audience who wants updated information.

The Effects of Oncolytic Pseudorabies Virus Vaccine Strain Inhibited the Growth of Colorectal Cancer HCT-8 Cells In Vitro and In Vivo

Oncolytic viral therapy is a promising treatment approach for a variety of tumor forms. Although a number of studies have demonstrated that the pseudorabies virus (PRV) may be applied as an oncolytic carrier, the anti-colorectal cancer impact of the virus and the mechanism of its cytotoxic effect remain elusive. In this study, the replication capacity and cell activity of PRV attenuated live vaccines Bartha K61 and HB98 in HCT-8 cells in vitro were investigated. Next, the antitumor ability and safety were evaluated in a mouse model of HCT-8 tumor transplantation. Both PRV strains were able to suppress tumor growth and HB98 showed higher safety and efficiency than the Bartha K61 strain. Finally, flow cytometry and immunohistochemistry examination were performed to investigate its possible cytotoxic mechanism. The results showed that PRV inhibited tumor proliferation both in vitro and in vivo by inducing apoptosis. In summary, our study discovered for the first time that the live attenuated PRV has an oncolytic effect on HCT-8 cells with high efficacy and safety.

Development of Molecular Mechanisms and Their Application on Oncolytic Newcastle Disease Virus in Cancer Therapy

Cancer is caused by the destruction or mutation of cellular genetic materials induced by environmental or genetic factors. It is defined by uncontrolled cell proliferation and abnormality of the apoptotic pathways. The majority of human malignancies are characterized by distant metastasis and dissemination. Currently, the most common means of cancer treatment include surgery, radiotherapy, and chemotherapy, which usually damage healthy cells and cause toxicity in patients. Targeted therapy is an effective tumor treatment method with few side effects. At present, some targeted therapeutic drugs have achieved encouraging results in clinical studies, but finding an effective solution to improve the targeting and delivery efficiency of these drugs remains a challenge. In recent years, oncolytic viruses (OVs) have been used to direct the tumor-targeted therapy or immunotherapy. Newcastle disease virus (NDV) is a solid oncolytic agent capable of directly killing tumor cells and increasing tumor antigen exposure. Simultaneously, NDV can trigger the proliferation of tumor-specific immune cells and thus improve the therapeutic efficacy of NDV in cancer. Based on NDV’s inherent oncolytic activity and the stimulation of antitumor immune responses, the combination of NDV and other tumor therapy approaches can improve the antitumor efficacy while reducing drug toxicity, indicating a broad application potential. We discussed the biological properties of NDV, the antitumor molecular mechanisms of oncolytic NDV, and its application in the field of tumor therapy in this review. Furthermore, we presented new insights into the challenges that NDV will confront and suggestions for increasing NDV’s therapeutic efficacy in cancer.

Evaluation of Host Cell Impurity Effects on the Performance of Sterile Filtration Processes for Therapeutic Viruses

Efficient downstream processing represents a significant challenge in the rapidly developing field of therapeutic viruses. While it is known that the terminal sterile filtration step can be a major cause of product loss, there is little known about the effect of host cell impurities (DNA and protein) on filtration performance. In this study, fractions of relatively pure Vero host cell protein and DNA were spiked into a highly pure preparation of vesicular stomatitis virus (VSV). Then, the resulting solutions were sterile filtered using two commercially available 0.22 µm rated microfiltration membranes. A combination of transmembrane pressure measurements, virus recovery measurements, and post-filtration microscopy images of the microfiltration membranes was used to evaluate the sterile filtration performance. It was found that increasing the amount of host cell protein from approximately 1 µg/mL (in the un-spiked VSV preparation) to 25 µg/mL resulted in a greater extent of membrane fouling, causing the VSV recovery to decrease from 89% to 65% in experiments conducted with the highly asymmetric Express PLUS PES membrane and to go as low as 48% in experiments conducted with the symmetric Durapore PVDF membrane. Similar effects were not seen when bovine serum albumin, a common model protein used in filtration studies, was spiked into the VSV preparation, which indicates that the sterile filtration performance is critically dependent on the complex composition of the mixture of host cell proteins rather than the presence of any protein. The results presented in this work provide important insights into the role of host cell impurities on the performance of sterile filtration processes for therapeutic viruses.

Cancer immunotherapy in adult patients with HIV

The availability of antiretroviral therapy (ART) has increased the life expectancy of people with HIV (PWH) and reduced the incidence of AIDS-associated malignancies, yet PWH have a significantly increased incidence of malignancy and less favorable outcomes of cancer treatment compared with the general population.Immunotherapy has revolutionized cancer therapy, becoming the standard of care for various malignancy treatments. However, PWH are an underserved population with limited access to clinical trials and cancer treatment.This review of the available evidence on different classes of cancer immunotherapy in PWH is mostly based on case reports, case series, but few prospective studies and clinical trials due to the exclusion of PWH from most oncologic clinical trials. The results of the available evidence support the safety of immunotherapy in PWH. Immunotherapy has similar effectiveness in PWH, an acceptable toxicity profile, and has no clinically significant impact on HIV viral load and CD4-T cell count. In addition, there is no reported change in the incidence of opportunistic infections and other complications for PWH with well-controlled viremia.This review aims to briefly summarize the current state of immunotherapy in cancer, guide clinicians in the management of immunotherapy in cancer PWH, and encourage the inclusion of PWH in clinical trials of cancer immunotherapy.

Giving Oncolytic Viruses a Free Ride: Carrier Cells for Oncolytic Virotherapy

Oncolytic viruses (OVs) are an emerging class of therapeutics which combine multiple mechanisms of action, including direct cancer cell-killing, immunotherapy and gene therapy. A growing number of clinical trials have indicated that OVs have an excellent safety profile and provide some degree of efficacy, but to date only a single OV drug, HSV-1 talimogene laherparepvec (T-Vec), has achieved marketing approval in the US and Europe. An important issue to consider in order to accelerate the clinical advancement of OV agents is the development of an effective delivery system. Currently, the most commonly employed OV delivery route is intratumoral; however, to target metastatic diseases and tumors that cannot be directly accessed, it is of great interest to develop effective approaches for the systemic delivery of OVs, such as the use of carrier cells. In general, the ideal carrier cell should have a tropism towards the tumor microenvironment (TME), and it must be susceptible to OV infection but remain viable long enough to allow migration and finally release of the OV within the tumor bed. Mesenchymal stem cells (MSCs) have been heavily investigated as carrier cells due to their inherent tumor tropism, in spite of some disadvantages in biodistribution. This review focuses on the other promising candidate carrier cells under development and discusses their interaction with specific OVs and future research lines.

Oncolytic virus therapy in cancer: A current review

In view of the advancement in the understanding about the most diverse types of cancer and consequently a relentless search for a cure and increased survival rates of cancer patients, finding a therapy that is able to combat the mechanism of aggression of this disease is extremely important. Thus, oncolytic viruses (OVs) have demonstrated great benefits in the treatment of cancer because it mediates antitumor effects in several ways. Viruses can be used to infect cancer cells, especially over normal cells, to present tumor-associated antigens, to activate "danger signals" that generate a less immune-tolerant tumor microenvironment, and to serve transduction vehicles for expression of inflammatory and immunomodulatory cytokines. The success of therapies using OVs was initially demonstrated by the use of the genetically modified herpes virus, talimogene laherparepvec, for the treatment of melanoma. At this time, several OVs are being studied as a potential treatment for cancer in clinical trials. However, it is necessary to be aware of the safety and possible adverse effects of this therapy; after all, an effective treatment for cancer should promote regression, attack the tumor, and in the meantime induce minimal systemic repercussions. In this manuscript, we will present a current review of the mechanism of action of OVs, main clinical uses, updates, and future perspectives on this treatment.

Oncolytic Bovine Herpesvirus 1 Inhibits Human Lung Adenocarcinoma A549 Cell Proliferation and Tumor Growth by Inducing DNA Damage

Bovine herpesvirus 1 (BoHV-1) is a promising oncolytic virus with broad antitumor spectrum; however, its oncolytic effects on human lung adenocarcinoma in vivo have not been reported. In this study, we report that BoHV-1 can be used as an oncolytic virus for human lung adenocarcinoma, and elucidate the underlying mechanism of how BoHV-1 suppresses tumor cell proliferation and growth. First, we examined the oncolytic activities of BoHV-1 in human lung adenocarcinoma A549 cells. BoHV-1 infection reduced the protein levels of histone deacetylases (HDACs), including HDAC1-4 that are promising anti-tumor drug targets. Furthermore, the HDAC inhibitor Trichostatin A (TSA) promoted BoHV-1 infection and exacerbated DNA damage and cytopathology, suggesting a synergy between BoHV-1 and TSA. In the A549 tumor xenograft mouse model, we, for the first time, showed that BoHV-1 can infect tumor and suppressed tumor growth with a similar high efficacy as the treatment of TSA, and HDACs have potential effects on the virus replication. Taken together, our study demonstrates that BoHV-1 has oncolytic effects against human lung adenocarcinoma in vivo.

The Effect of Herpes Simplex Virus-Type-1 (HSV-1) Oncolytic Immunotherapy on the Tumor Microenvironment

The development of cancer causes disruption of anti-tumor immunity required for surveillance and elimination of tumor cells. Immunotherapeutic strategies aim for the restoration or establishment of these anti-tumor immune responses. Cancer immunotherapies include immune checkpoint inhibitors (ICIs), adoptive cellular therapy (ACT), cancer vaccines, and oncolytic virotherapy (OVT). The clinical success of some of these immunotherapeutic modalities, including herpes simplex virus type-1 derived OVT, resulted in Food and Drug Administration (FDA) approval for use in treatment of human cancers. However, a significant proportion of patients do not respond or benefit equally from these immunotherapies. The creation of an immunosuppressive tumor microenvironment (TME) represents an important barrier preventing success of many immunotherapeutic approaches. Mechanisms of immunosuppression in the TME are a major area of current research. In this review, we discuss how oncolytic HSV affects the tumor microenvironment to promote anti-tumor immune responses. Where possible we focus on oncolytic HSV strains for which clinical data is available, and discuss how these viruses alter the vasculature, extracellular matrix and immune responses in the tumor microenvironment.

Mesenchymal stem cell carriers enhance anti-tumor efficacy of oncolytic virotherapy

Oncolytic viruses (OVs) specifically infect, replicate and eventually destroy tumor cells, with no concomitant toxicity to adjacent normal cells. Furthermore, OVs can regulate tumor microenvironments and stimulate anti-tumor immune responses. Mesenchymal stem cells (MSCs) have inherent tumor tropisms and immunosuppressive functions. MSCs carrying OVs not only protect viruses from clearing by the immune system, but they also deliver the virus to tumor lesions. Equally, cytokines released by MSCs enhance anti-tumor immune responses, suggesting that MSCs carrying OVs may be considered as a promising strategy in enhancing the anti-tumor efficacies of virotherapy. In the present review, preclinical and clinical studies were evaluated and discussed, as well as the effectiveness of MSCs carrying OVs for tumor treatment.

Latest evidence on immunotherapy for cholangiocarcinoma

Cholangiocarcinoma (CCA) is a type of aggressive tumor that involves the intrahepatic, perihilar and distal biliary tree, and is usually diagnosed at an advanced stage. The standard first-line systemic therapy for patients with advanced CCA is a combination of gemcitabine and cisplatin; targeted therapies and angiogenesis inhibitors are not widely used clinically at present. However, with the development of precision medicine, immunotherapy has started to play a more important role. Programmed cell death protein 1 inhibitors are now considered a good therapeutic option for CCA. Treatments using chimeric antigen receptor T cells, bispecific antibodies, oncolytic viruses and cancer vaccines have also achieved satisfactory results. In addition, combinations of immunotherapy with a variety of conventional therapies have shown some efficacy, and several studies have provided insights into their use in antitumor therapy. Although there are numerous challenges in the treatment of advanced CCA, immunotherapy remains a noteworthy breakthrough. The current evidence on the immunotherapy of CCA is discussed in the present review.

Engineered Bacteriophage T7 as a Potent Anticancer Agent in vivo

Oncolytic viruses (OVs) induce antitumor effect by both direct lysis of target cells and eliciting immunogenic response to the virus and ultimately to the target cells. These viruses are usually natural human pathogens. Bacteriophages are natural pathogens of bacteria that do not infect human and have greater advantages in safety, manipulation, and production over human viruses. We constructed an engineered bacteriophage T7 displaying a peptide, which targets murine melanoma cells and harbors a mammalian expression cassette of the cytokine granulocyte macrophage-colony stimulating factor (GM-CSF) in viral genomic DNA. The engineered phage was successfully transduced to B16F10 melanoma cells both in vitro and in vivo. GM-CSF was expressed from the transduced phage DNA. All mice treated with the phage intravenously survived for 25 days until the end of experiment, while only 40% of those not treated survived. During the 16 days of phage treatment, phage T7 displaying homing peptide and expressing GM-CSF inhibited tumor growth by 72% compared to the untreated control. Serum cytokine levels of IL-1α, TNF-α, and GM-CSF were seen to increase during the treatment. Immunohistochemical analysis of tumor tissue revealed infiltration by macrophages, dendritic cells (DCs), and CD8⁺ T cells. Migration of murine macrophages to bacteriophages was also observed in in vitro transwell assays in both time- and dose-dependent manners. Taken together, the recombinant bacteriophage T7 efficiently inhibited tumor growth by changing the tumor microenvironment and recruiting anti-tumor immune cells.

Observational study of talimogene laherparepvec use in the anti-PD-1 era for melanoma in the US (COSMUS-2)

AIM

Talimogene laherparepvec (T-VEC) is an intralesional therapy for unresectable, metastatic melanoma. T-VEC real-world use in the context of anti-PD1-based therapy requires further characterization.

MATERIALS & METHODS

A retrospective review of T-VEC use from 1 January 2017 and 31 March 2018 for melanoma patients was conducted at seven US institutions.

RESULTS

Among 83 patients, three categories of T-VEC and anti-PD-1 therapy were identified: T-VEC used without anti-PD-1 (n = 29, 35%), T-VEC after anti-PD-1-based therapy (n = 22, 27%) and concurrent T-VEC and anti-PD-1-based therapy (n = 32, 39%). 25% of patients discontinued T-VEC therapy due to no remaining injectable lesions, 37% discontinued T-VEC due to progressive disease. Discontinuation of T-VEC did not differ by anti-PD-1-based therapy use or timing.

CONCLUSION

In real-world settings, T-VEC may be used concurrently with or after anti-PD-1-based therapy.

Protein Expression in Metastatic Melanoma and the Link to Disease Presentation in a Range of Tumor Phenotypes

Malignant melanoma is among the most aggressive skin cancers and it has among the highest metastatic potentials. Although surgery to remove the primary tumor is the gold standard treatment, once melanoma progresses and metastasizes to the lymph nodes and distal organs, i.e., metastatic melanoma (MM), the usual outcome is decreased survival. To improve survival rates and life span, advanced treatments have focused on the success of targeted therapies in the MAPK pathway that are based on BRAF (BRAF V600E) and MEK. The majority of patients with tumors that have higher expression of BRAF V600E show poorer prognosis than patients with a lower level of the mutated protein. Based on the molecular basis of melanoma, these findings are supported by distinct tumor phenotypes determined from differences in tumor heterogeneity and protein expression profiles. With these aspects in mind, continued challenges are to: (1) deconvolute the complexity and heterogeneity of MM; (2) identify the signaling pathways involved; and (3) determine protein expression to develop targeted therapies. Here, we provide an overview of the results from protein expression in MM and the link to disease presentation in a variety of tumor phenotypes and how these will overcome the challenges of clinical problems and suggest new promising approaches in metastatic melanoma and cancer therapy.

Modeling the Efficacy of Oncolytic Adenoviruses In Vitro and In Vivo: Current and Future Perspectives

Oncolytic adenoviruses (OAd) selectively target and lyse tumor cells and enhance anti- tumor immune responses. OAds have been used as promising cancer gene therapies for many years and there are a multitude of encouraging pre-clinical studies. However, translating OAd therapies to the clinic has had limited success, in part due to the lack of realistic pre-clinical models to rigorously test the efficacy of OAds. Solid tumors have a heterogenous and hostile microenvironment that provides many barriers to OAd treatment, including structural and immunosuppressive components that cannot be modeled in two-dimensional tissue culture. To replicate these characteristics and bridge the gap between pre-clinical and clinical success, studies must test OAd therapy in three-dimensional culture and animal models. This review focuses on current methods to test OAd efficacy in vitro and in vivo and the development of new model systems to test both oncolysis and immune stimulatory components of oncolytic adenovirotherapy.

Emergence in protein derived nanomedicine as anticancer therapeutics: More than a tour de force

Cancer has thwarted as a major health problem affecting the global population. With an alarming increase in the patient population suffering from diverse varieties of cancers, the global demographic data predicts sharp escalation in the number of cancer patients. This can be expected to reach 420 million cases by 2025. Among the diverse types of cancers, the most frequently diagnosed cancers are the breast, colorectal, prostate and lung cancer. From years, conventional treatment approaches like surgery, chemotherapy and radiation therapy have been practiced. In the past few years, increasing research on molecular level diagnosis and treatment of cancers have significantly changed the realm of cancer treatment. Lately, uses of advanced chemotherapy and immunotherapy like treatments have gained significant progress in the cancer therapy, but these approaches have several limitations on their safety and toxicity. This has generated lot of momentum for the evolution of new drug delivery approaches for the effective delivery of anticancer therapeutics, which may improve the pharmacokinetic and pharmacodynamic effect of the drugs along with significant reduction in the side effects. In this regard, the protein-based nano-medicines have gained wider attention in the management of cancer. Proteins are organic macromolecules essential, for life and have quite well explored in developing the nano-carriers. Furthermore, it provides passive or active tumour cell targeted delivery, by using protein based nanovesicles or virus like structures, antibody drug conjugates, viral particles, etc. Moreover, by utilizing various formulation strategies, both the animal and plant derived proteins can be converted to produce self-assembled virus like nano-metric structures with high efficiency in targeting the metastatic cancer cells. Therefore, the present review extensively discusses the applications of protein-based nano-medicine with special emphasis on intracellular delivery/drug targeting ability for anticancer drugs.

Oncolytic Viruses for Cancer Therapy: Barriers and Recent Advances

Oncolytic viruses (OVs) are powerful new therapeutic agents in cancer therapy. With the first OV (talimogene laherparepvec [T-vec]) obtaining US Food and Drug Administration approval, interest in OVs has been boosted greatly. Nevertheless, despite extensive research, oncolytic virotherapy has shown limited efficacy against solid tumors. Recent advances in viral retargeting, genetic editing, viral delivery platforms, tracking strategies, OV-based gene therapy, and combination strategies have the potential to broaden the applications of oncolytic virotherapy in oncology. In this review, we present several insights into the limitations and challenges of oncolytic virotherapy, describe the strategies mentioned above, provide a summary of recent preclinical and clinical trials in the field of oncolytic virotherapy, and highlight the need to optimize current strategies to improve clinical outcomes.

Biodistribution, shedding, and transmissibility of the oncolytic virus talimogene laherparepvec in patients with melanoma

Background

Talimogene laherparepvec (T-VEC) is an intralesionally delivered, modified herpes simplex virus type-1 oncolytic immunotherapy. The biodistribution, shedding, and potential transmission of T-VEC was systematically evaluated during and after completion of therapy in adults with advanced melanoma.

Methods

In this phase 2, single-arm, open-label study, T-VEC was administered into injectable lesions initially at 10⁶ plaque-forming units (PFU)/mL, 10⁸ PFU/mL 21 days later, and 10⁸ PFU/mL every 14 (±3) days thereafter. Injected lesions were covered with occlusive dressings for ≥1 week. Blood, urine, and swabs from exterior of occlusive dressings, surface of injected lesions, oral mucosa, anogenital area, and suspected herpetic lesions were collected throughout the study. Detectable T-VEC DNA was determined for each sample type; infectivity was determined for all swabs with detectable T-VEC DNA.

Findings

Sixty patients received ≥1 dose of T-VEC. During cycles 1–4, T-VEC DNA was detected in blood (98·3% of patients, 36·7% of samples), urine (31·7% of patients, 3·0% of samples) and swabs from injected lesions (100% of patients, 57·6% of samples), exterior of dressings (80% of patients,19·5% of samples), oral mucosa (8·3% of patients, 2·5% of samples), and anogenital area (8·0% of patients, 1·1% of samples). During the safety follow-up period, T-VEC DNA was only detected on swabs from injected lesions (14% of patients, 5.8% of samples). T-VEC DNA was detected in 4/37 swabs (3/19 patients) of suspected herpetic lesions. Among all samples, only those from the surface of injected lesions tested positive for infectivity (8/740 [1·1%]). Three close contacts reported signs and symptoms of suspected herpetic origin; however, no lesions had detectable T-VEC DNA.

Interpretation

Using current guidelines, T-VEC can be administered safely to patients with advanced melanoma and is unlikely to be transmitted to close contacts with appropriate use of occlusive dressings.

Fund

This study was funded by Amgen Inc.: ClinicalTrials.gov, NCT02014441.