Nanotechnology and nano-sized tools: Newer approaches to circumvent oncolytic adenovirus limitations.

Oncolytic adenoviruses (OAds), engineered Ads preferentially infect and lyse tumor cells, have attracted remarkable attention as immunotherapy weapons for the treatment of various malignancies. Despite hopeful successes in preclinical investigations and translation into clinical phases, they face some challenges that thwart their therapeutic effectiveness, including low infectivity of cancer cells, liver sequestration, pre-existing neutralizing antibodies, physical barriers to the spread of Ads, and immunosuppressive TME. Nanotechnology and nano-sized tools provide several advantages to overcome these limitations of OAds. Nano-sized tools could improve the therapeutic efficacy of OAds by enhancing infectivity and cellular uptake, targeting and protecting from pre-existing immune responses, masking and preventing liver tropism, and co-delivery with other therapeutic agents. Herein, we reviewed the constructs of various OAds and their application in clinical trials, as well as the limitations they have faced. Furthermore, we emphasized the potential applications of nanotechnology to solve the constraints of OAds to improve their anti-tumor activities.

Immunovirotherapy: The role of antibody based therapeutics combination with oncolytic viruses.

Despite the fact that the new drugs and targeted therapies have been approved for cancer therapy during the past 30 years, the majority of cancer types are still remain challenging to be treated. Due to the tumor heterogeneity, immune system evasion and the complex interaction between the tumor microenvironment and immune cells, the great majority of malignancies need multimodal therapy. Unfortunately, tumors frequently develop treatment resistance, so it is important to have a variety of therapeutic choices available for the treatment of neoplastic diseases. Immunotherapy has lately shown clinical responses in malignancies with unfavorable outcomes. Oncolytic virus (OV) immunotherapy is a cancer treatment strategy that employs naturally occurring or genetically-modified viruses that multiply preferentially within cancer cells. OVs have the ability to not only induce oncolysis but also activate cells of the immune system, which in turn activates innate and adaptive anticancer responses. Despite the fact that OVs were translated into clinical trials, with T-VECs receiving FDA approval for melanoma, their use in fighting cancer faced some challenges, including off-target side effects, immune system clearance, non-specific uptake, and intratumoral spread of OVs in solid tumors. Although various strategies have been used to overcome the challenges, these strategies have not provided promising outcomes in monotherapy with OVs. In this situation, it is increasingly common to use rational combinations of immunotherapies to improve patient benefit. With the development of other aspects of cancer immunotherapy strategies, combinational therapy has been proposed to improve the anti-tumor activities of OVs. In this regard, OVs were combined with other biotherapeutic platforms, including various forms of antibodies, nanobodies, chimeric antigen receptor (CAR) T cells, and dendritic cells, to reduce the side effects of OVs and enhance their efficacy. This article reviews the promising outcomes of OVs in cancer therapy, the challenges OVs face and solutions, and their combination with other biotherapeutic agents.

Metabolic risk factors of ovarian cancer: a review.

Ovarian cancer continues to be the leading cause of death from gynecological cancers. Despite inconsistent results, patients with metabolic abnormalities, including obesity and diabetes mellitus (DM), have poorer outcomes, showing a correlation with ovarian cancer incidence and ovarian cancer survival. Since ovarian cancer is the most common cancer in women, and considering the increasing prevalence of obesity and DM, this paper reviews the literature regarding the relationship between the aforementioned metabolic derangements and ovarian cancer, with a focus on ovarian cancer incidence, mortality, and likely mechanisms behind them. Several systematic reviews and meta-analyses have shown that obesity is associated with a higher incidence and poorer survival in ovarian cancer. Although more studies are required to investigate the etiological relation of DM and ovarian cancer, sufficient biological evidence indicates poorer outcomes and shorter survival in DM women with ovarian cancer. A variety of pathologic factors may contribute to ovarian cancer risk, development, and survival, including altered adipokine expression, increased levels of circulating growth factors, altered levels of sex hormones, insulin resistance, hyperinsulinemia, and chronic inflammation. Thus, obesity and DM, as changeable risk factors, can be targeted for intervention to prevent ovarian cancer and improve its outcomes.

Oncolytic virotherapy as promising immunotherapy against cancer: mechanisms of resistance to oncolytic viruses.

Oncolytic virotherapy has currently emerged as a powerful therapeutic approach in cancer treatment. Although the history of using viruses goes back to the early 20th century, the approval of talimogene laherparepvec (T-VEC) in 2015 increased interest in oncolytic viruses (OVs). OVs are multifaceted biotherapeutic agents because they replicate in and kill tumor cells and augment immune responses by releasing immunostimulatory molecules from lysed cells. Despite promising results, some limitations hinder the efficacy of oncolytic virotherapy. The delivery challenges and the upregulation of checkpoints following oncolytic virotherapy also mediate resistance to OVs by diminishing immune responses. Furthermore, the localization of receptors of viruses in the tight junctions, interferon responses, and the aberrant expression of genes involved in the cell cycle of the virus, including their infection and replication, reduce the efficacy of OVs. In this review, we present different mechanisms of resistance to OVs and strategies to overcome them.

Lay abstract Using viruses in the treatment of cancer goes back to the early 20th century. One of the promising fields in cancer virotherapy is viruses' ability to preferentially lysis tumor cells, either naturally or genetically engineered cells; these viruses are termed 'oncolytic viruses.' As with other therapeutic strategies, resistance to the oncolytic viruses is the main challenge in their application in clinical trials. This review summarizes the mechanisms of resistance to oncolytic viruses and the strategies that have been used to overcome these challenges.

Heterologous administration of HPV16 E7 epitope-loaded nanocomplexes inhibits tumor growth in mouse model.

The nanostructured complexes can result in enhanced vaccine efficacy by facilitating the distribution and uptake of antigens by antigen-presenting cells (APCs), thereby stimulating immune responses. Here, we hypothesized that either directly coating of nanoadjuvants including aluminum phosphate (AlPO4) and adenovirus (Ad) with a modified HPV16 E7 MHC-I specific epitope, RAHYNIVTF49-57, or mixing the CpG oligodeoxynucleotide (CpG-ODN) with the cationic epitope to form nanocomlexes, and their combinational therapy would enhance their anti-tumor effects in a TC-1 mouse model. The positively-charged HPV16 E7 epitope was attracted to the oppositely-charged adjuvants by electrostatic interaction to generate epitope/adjuvant nanocomplexes. We showed that coating the nanosized adjuvants with the cationic epitope increased the particles' surface charge without significant change in their size. We then tested the cellular immunogenicity and therapeutic efficacy of nanocomplexes by measuring IL-10 and IFN-γ production, the expression of CD107a as a marker of CTL response, and tumor growth inhibition. The nanocomplexes were administered either in homologous or heterologous prime-boost regimens, and heterologous immunizations including Ad/Pep-CpG/Pep, CpG/Pep-Ad/Pep, Ad/Pep-Alum/Pep, and Alum/Pep-Ad/Pep induced significantly higher levels of IL-10, IFN-γ, and CD107a-expressing CD8 T cells compared with homologous administrations. Furthermore, the tumor growth was significantly suppressed in mice receiving nanostructured complexes in the heterologous immunizations. Our study highlights the potential of the heterologous prime-boost administration of the epitope-coated nanostructures as an effective immunization strategy.

Virus against virus: strategies for using adenovirus vectors in the treatment of HPV-induced cervical cancer.

Although most human papillomavirus (HPV) infections are harmless, persistent infection with high-risk types of HPV is known to be the leading cause of cervical cancer. Following the infection of the epithelium and integration into the host genome, the oncogenic proteins E6 and E7 disrupt cell cycle control by inducing p53 and retinoblastoma (Rb) degradation. Despite the FDA approval of prophylactic vaccines, there are still issues with cervical cancer treatment; thus, many therapeutic approaches have been developed to date. Due to strong immunogenicity, a high capacity for packaging foreign DNA, safety, and the ability to infect a myriad of cells, adenoviruses have drawn attention of researchers. Adenovirus vectors have been used for different purposes, including as oncolytic agents to kill cancer cells, carrier for RNA interference to block oncoproteins expression, vaccines for eliciting immune responses, especially in cytotoxic T lymphocytes (CTLs), and gene therapy vehicles for restoring p53 and Rb function.

Oncolytic virotherapy: Challenges and solutions.

Viruses as cancer therapies have attracted attention since the 19th century. Scientists observation that viruses can preferentially lyse cancer cells rather than healthy cells, created the field of oncolytic virology. Like other therapeutic strategies, oncolytic virotherapy has challenges, such as penetration into tumor bulk, anti-viral immune responses, off-target infection, adverse conditions in the tumor microenvironment, and the lack of specific predictive and therapeutic biomarkers. Whilst much progress has been made, as highlighted by the first Food and Drug Administration approval of an oncolytic virus talimogene laherparepvec (T-VEC) in 2015, addressing these issues remains a significant hurdle. Here we discuss different types of oncolytic viruses, their application in clinical trials, and finally challenges faced by the field of oncolytic virotherapy and strategies to overcome them.

Overcoming the blood-brain barrier in neurodegenerative disorders and brain tumours.

Drug delivery is one of the major challenges in the treatment of central nervous system disorders. The brain needs to be protected from harmful agents, which are done by the capillary network, the so-called blood-brain barrier (BBB). This protective guard also prevents the delivery of therapeutic agents to the brain and limits the effectiveness of treatment. For this reason, various strategies have been explored by scientists for overcoming the BBB from disruption of the BBB to targeted delivery of nanoparticles (NPs) and cells and immunotherapy. In this review, different promising brain drug delivery strategies including disruption of tight junctions in the BBB, enhanced transcellular transport by peptide-based delivery, local delivery strategies, NP delivery, and cell-based delivery have been fully discussed.

Strategies for enhancing intratumoral spread of oncolytic adenoviruses.

Oncolytic viruses, effectively replicate viruses within malignant cells to lyse them without affecting normal ones, have recently shown great promise in developing therapeutic options for cancer. Adenoviruses (Ads) are one of the candidates in oncolytic virotheraoy due to its easily manipulated genomic DNA and expression of wide rane of its receptors on the various cancers. Although systematic delivery of oncolytic adenoviruses can target both primary and metastatic tumors, there are some drawbacks in the effective systematic delivery of oncolytic adenoviruses, including pre-existing antibodies and liver tropism. To overcome these limitations, intratumural (IT) administration of oncolytic viruses have been proposed. However, IT injection of Ads leaves much of the tumor mass unaffected and Ads are not able to disperse more in the tumor microenvironment (TME). To this end, various strategies have been developed to enhance the IT spread of oncolytic adenoviruses, such as using extracellular matrix degradation enzymes, junction opening peptides, and fusogenic proteins. In the present paper, we reviewed different oncolytic adenoviruses, their application in the clinical trials, and strategies for enhancing their IT spread.

Tumor microenvironment: Interactions and therapy.

Tumor microenvironment (TME) is a host for a complex network of heterogeneous stromal cells with overlapping or opposing functions depending on the dominant signals within this milieu. Reciprocal paracrine interactions between cancer cells with cells within the tumor stroma often reshape the TME in favor of the promotion of tumor. These complex interactions require more sophisticated approaches for cancer therapy, and, therefore, advancing knowledge about dominant drivers of cancer within the TME is critical for designing therapeutic schemes. This review will provide knowledge about TME architecture, multiple signaling, and cross communications between cells within this milieu, and its targeting for immunotherapy of cancer.

Oncolytic adenovirus: A tool for cancer therapy in combination with other therapeutic approaches.

Cancer therapy using oncolytic viruses is an emerging area, in which viruses are engineered to selectively propagate in tumor tissues without affecting healthy cells. Because of the advantages that adenoviruses (Ads) have over other viruses, they are more considered. To achieve tumor selectivity, two main modifications on Ads genome have been applied: small deletions and insertion of tissue- or tumor-specific promoters. Despite oncolytic adenoviruses ability in tumor cell lysis and immune responses stimulation, to further increase their antitumor effects, genomic modifications have been carried out including insertion of checkpoint inhibitors and antigenic or immunostimulatory molecules into the adenovirus genome and combination with dendritic cells and chemotherapeutic agents. This study reviews oncolytic adenoviruses structures, their antitumor efficacy in combination with other therapeutic strategies, and finally challenges around this treatment approach.

Curcumin as an anti-inflammatory agent: Implications to radiotherapy and chemotherapy.

Cancer is the second cause of death worldwide. Chemotherapy and radiotherapy are the most common modalities for the treatment of cancer. Experimental studies have shown that inflammation plays a central role in tumor resistance and the incidence of several side effects following both chemotherapy and radiotherapy. Inflammation resulting from radiotherapy and chemotherapy is responsible for adverse events such as dermatitis, mucositis, pneumonitis, fibrosis, and bone marrow toxicity. Chronic inflammation may also lead to the development of second cancer during years after treatment. A number of anti-inflammatory drugs such as nonsteroidal anti-inflammatory agents have been proposed to alleviate chronic inflammatory reactions after radiotherapy or chemotherapy. Curcumin is a well-documented herbal anti-inflammatory agents. Studies have proposed that curcumin can help management of inflammation during and after radiotherapy and chemotherapy. Curcumin targets various inflammatory mediators such as cyclooxygenase-2, inducible nitric oxide synthase, and nuclear factor κB (NF-κB), thereby attenuating the release of proinflammatory and profibrotic cytokines, and suppressing chronic production of free radicals, which culminates in the amelioration of tissue toxicity. Through modulation of NF-κB and its downstream signaling cascade, curcumin can also reduce angiogenesis, tumor growth, and metastasis. Low toxicity of curcumin is linked to its cytoprotective effects in normal tissues. This protective action along with the capacity of this phytochemical to sensitize tumor cells to radiotherapy and chemotherapy makes it a potential candidate for use as an adjuvant in cancer therapy. There is also evidence from clinical trials suggesting the potential utility of curcumin for acute inflammatory reactions during radiotherapy such as dermatitis and mucositis.

NADPH Oxidase as a Target for Modulation of Radiation Response; Implications to Carcinogenesis and Radiotherapy.

BACKGROUND: Radiotherapy is a treatment modality for cancer. For better therapeutic efficiency, it could be used in combination with surgery, chemotherapy or immunotherapy. In addition to its beneficial therapeutic effects, exposure to radiation leads to several toxic effects on normal tissues. Also, it may induce some changes in genomic expression of tumor cells, thereby increasing the resistance of tumor cells. These changes lead to the appearance of some acute reactions in irradiated organs, increased risk of carcinogenesis, and reduction in the therapeutic effect of radiotherapy. DISCUSSION: So far, several studies have proposed different targets such as cyclooxygenase-2 (COX-2), some toll-like receptors (TLRs), mitogen-activated protein kinases (MAPKs) etc., for the amelioration of radiation toxicity and enhancing tumor response. NADPH oxidase includes five NOX and two dual oxidases (DUOX1 and DUOX2) subfamilies that through the production of superoxide and hydrogen peroxide, play key roles in oxidative stress and several signaling pathways involved in early and late effects of ionizing radiation. Chronic ROS production by NOX enzymes can induce genomic instability, thereby increasing the risk of carcinogenesis. Also, these enzymes are able to induce cell death, especially through apoptosis and senescence that may affect tissue function. ROS-derived NADPH oxidase causes apoptosis in some organs such as intestine and tongue, which mediate inflammation. Furthermore, continuous ROS production stimulates fibrosis via stimulation of fibroblast differentiation and collagen deposition. Evidence has shown that in contrast to normal tissues, the NOX system induces tumor resistance to radiotherapy through some mechanisms such as induction of hypoxia, stimulation of proliferation, and activation of macrophages. However, there are some contradictory results. Inhibition of NADPH oxidase in experimental studies has shown promising results for both normal tissue protection and tumor sensitization to ionizing radiation. CONCLUSION: In this article, we aimed to review the role of different subfamilies of NADPH oxidase in radiation-induced early and late normal tissue toxicities in different organs.

Melatonin and cancer: From the promotion of genomic stability to use in cancer treatment.

Cancer remains among the most challenging human diseases. Several lines of evidence suggest that carcinogenesis is a complex process that is initiated by DNA damage. Exposure to clastogenic agents such as heavy metals, ionizing radiation (IR), and chemotherapy drugs may cause chronic mutations in the genomic material, leading to a phenomenon named genomic instability. Evidence suggests that genomic instability is responsible for cancer incidence after exposure to carcinogenic agents, and increases the risk of secondary cancers following treatment with radiotherapy or chemotherapy. Melatonin as the main product of the pineal gland is a promising hormone for preventing cancer and improving cancer treatment. Melatonin can directly neutralize toxic free radicals more efficiently compared with other classical antioxidants. In addition, melatonin is able to regulate the reduction/oxidation (redox) system in stress conditions. Through regulation of mitochondrial nction and inhibition of pro-oxidant enzymes, melatonin suppresses chronic oxidative stress. Moreover, melatonin potently stimulates DNA damage responses that increase the tolerance of normal tissues to toxic effect of IR and may reduce the risk of genomic instability in patients who undergo radiotherapy. Through these mechanisms, melatonin attenuates several side effects of radiotherapy and chemotherapy. Interestingly, melatonin has shown some synergistic properties with IR and chemotherapy, which is distinct from classical antioxidants that are mainly used for the alleviation of adverse events of radiotherapy and chemotherapy. In this review, we describe the anticarcinogenic effects of melatonin and also its possible application in clinical oncology.

Intercellular communications-redox interactions in radiation toxicity; potential targets for radiation mitigation.

Nowadays, using ionizing radiation (IR) is necessary for clinical, agricultural, nuclear energy or industrial applications. Accidental exposure to IR after a radiation terror or disaster poses a threat to human. In contrast to the old dogma of radiation toxicity, several experiments during the last two recent decades have revealed that intercellular signaling and communications play a key role in this procedure. Elevated level of cytokines and other intercellular signals increase oxidative damage and inflammatory responses via reduction/oxidation interactions (redox system). Intercellular signals induce production of free radicals and inflammatory mediators by some intermediate enzymes such as cyclooxygenase-2 (COX-2), nitric oxide synthase (NOS), NADPH oxidase, and also via triggering mitochondrial ROS. Furthermore, these signals facilitate cell to cell contact and increasing cell toxicity via cohort effect. Nitric oxide is a free radical with ability to act as an intercellular signal that induce DNA damage and changes in some signaling pathways in irradiated as well as non-irradiated adjacent cells. Targeting of these mediators by some anti-inflammatory agents or via antioxidants such as mitochondrial ROS scavengers opens a window to mitigate radiation toxicity after an accidental exposure. Experiments which have been done so far suggests that some cytokines such as IL-1ß, TNF-α, TGF-ß, IL-4 and IL-13 are some interesting targets that depend on irradiated organs and may help mitigate radiation toxicity. Moreover, animal experiments in recent years indicated that targeting of toll like receptors (TLRs) may be more useful for radioprotection and mitigation. In this review, we aimed to describe the role of intercellular interactions in oxidative injury, inflammation, cell death and killing effects of IR. Moreover, we described evidence on potential mitigation of radiation injury via targeting of these mediators.

Stem Cell Therapy: A New Therapeutic Option for Cardiovascular Diseases.

Cardiovascular diseases are known as one of major causes of morbidity and mortality worldwide. Despite the many advancement in therapies are associated with cardiovascular diseases, it seems that finding of new therapeutic option is necessary. Cell therapy is one of attractive therapeutic platforms for treatment of a variety of diseases such as cardiovascular diseases. Among of various types of cell therapy, stem cell therapy has been emerged as an effective therapeutic approach in this area. Stem cells divided into multipotent stem cells and pluripotent stem cells. A large number studies indicated that utilization of each of them are associated with a variety of advantages and disadvantages. Multiple lines evidence indicated that stem cell therapy could be used as suitable therapeutic approach for treatment of cardiovascular diseases. Many clinical trials have been performed for assessing efficiency of stem cell therapies in human. However, stem cell therapy are associated with some challenges, but, it seems resolving of them could contribute to using of them as effective therapeutic approach for patients who suffering from cardiovascular diseases. In the current review, we summarized current therapeutic strategies based on stem cells for cardiovascular diseases. J. Cell. Biochem. 119: 95-104, 2018. © 2017 Wiley Periodicals, Inc.

Melatonin as an angiogenesis inhibitor to combat cancer: Mechanistic evidence.

Melatonin, a pineal indolamine, participates in different body functions and is shown to possess diverse biological activities such as anti-tumor action. Angiogenesis inhibition is one of the mechanisms by which melatonin exerts its oncostatic effects. Increased angiogenesis is a major feature of tumor progression, thus angiogenesis inhibition is a critical step in cancer therapy. Melatonin employs a variety of mechanisms to target nutrients and oxygen supply to cancer cells. At the transcriptional level, hypoxia induced factor-1α (HIF-1α) and the genes under its control, such as vascular endothelial growth factor (VEGF) are the main targets of melatonin for inhibition of angiogenesis. Melatonin prevents translocation of HIF-1α into the nucleus thereby hindering VEGF expression and also prevents the formation of HIF-1α, phospho-STAT3 and CBP/p300 complex which is involved in the expression of angiogenesis-related genes. Angiostatic properties of melatonin could be also due to its ability to inhibit VEGFR2's activation and expression. Other angiostatic mechanisms of melatonin include the inhibition of endothelial cell migration, invasion, and tube formation. In the present study, we have reviewed the molecular anti-angiogenesis pathways mediated by melatonin and the responsible mechanisms in various types of cancers both in vitro and in vivo.