Presence of the coxsackievirus and adenovirus receptor (CAR) in human neoplasms: a multitumour array analysis

The Immune System-A Double-Edged Sword for Adenovirus-Based Therapies

Pathogenic adenovirus (Ad) infections are widespread but typically mild and transient, except in the immunocompromised. As vectors for gene therapy, vaccine, and oncology applications, Ad-based platforms offer advantages, including ease of genetic manipulation, scale of production, and well-established safety profiles, making them attractive tools for therapeutic development. However, the immune system often poses a significant challenge that must be overcome for adenovirus-based therapies to be truly efficacious. Both pre-existing anti-Ad immunity in the population as well as the rapid development of an immune response against engineered adenoviral vectors can have detrimental effects on the downstream impact of an adenovirus-based therapeutic. This review focuses on the different challenges posed, including pre-existing natural immunity and anti-vector immunity induced by a therapeutic, in the context of innate and adaptive immune responses. We summarise different approaches developed with the aim of tackling these problems, as well as their outcomes and potential future applications.

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.

The junctional adhesion molecule-like protein (JAML) is important for the inflammatory response during contact hypersensitivity

BACKGROUND

The junctional adhesion molecule-like protein (JAML) plays important roles in wound healing and activation of epidermal γδ T cells in mice. Whether JAML plays a role in contact hypersensitivity (CHS), the animal model of allergic contact dermatitis (ACD), is not known.

METHODS

To examine the role of JAML in CHS, we used various mouse models of CHS in JAML knockout (KO) and wild-type (WT) mice. Furthermore, the expression of the JAML ligand coxsackievirus and adenovirus receptor (CXADR) on keratinocytes was accessed in vitro and in vivo.

RESULTS

JAML KO mice had a diminished inflammatory response during both the sensitization and elicitation phase of CHS and had reduced numbers of CD8+ and CD4+ T cells in the epidermis. Furthermore, interferon γ (IFNγ), interleukin 1β (IL-1β) and CXCL10 production were significantly reduced in JAML KO mice during the elicitation phase. We found that CD8+ T cells express JAML and that JAML is essential for rapid flare-up responses to contact allergens. Finally, we show that keratinocytes up-regulate the JAML ligand CXADR following exposure to contact allergens.

CONCLUSION

Our study is the first to show a central role of JAML in CHS and reveals a potential new target for the treatment of ACD in humans.

Fatty acids as histone deacetylase inhibitors: old biochemistry tales in a new life sciences town

Histone acetylation is a key epigenetic event. Although the keywords fatty acids, histones, and histone acetylation have a long history in biochemistry, these topics continue to attract much attention among researchers. The acetylation of histones is controlled by the activities of histone acetyltransferases (HATs) and histone deacetylases (HDACs). An imbalance in the activities of HATs and HDACs is common in a range of human cancers. Histone deacetylase inhibitors (HDACi) can restore dysregulated histone acetylation profiles in cancer cells and have been identified as promising anti-cancer therapeutics. Short-chain fatty acids mediate anti-cancer effects by inhibiting the activity of HDACs. Recent studies have identified odd-chain fatty acids as novel HDACi. This review summarizes recent findings regarding fatty acids as HDACi in cancer therapy. Teaser: Inhibition of histone deacetylase (HDAC) activity by fatty acids.

A Renaissance for Oncolytic Adenoviruses?

In the 1990s, adenovirus became one of the first virus types to be genetically engineered to selectively destroy cancer cells. In the intervening years, the field of "oncolytic viruses" has slowly progressed and culminated in 2015 with the FDA approval of Talimogene laherparepvec, a genetically engineered herpesvirus, for the treatment of metastatic melanoma. Despite the slower progress in translating oncolytic adenovirus to the clinic, interest in the virus remains strong. Among all the clinical trials currently using viral oncolytic agents, the largest proportion of these are using recombinant adenovirus. Many trials are currently underway to use oncolytic virus in combination with immune checkpoint inhibitors (ICIs), and early results using oncolytic adenovirus in this manner are starting to show promise. Many of the existing strategies to engineer adenoviruses were designed to enhance selective tumor cell replication without much regard to interactions with the immune system. Adenovirus possesses a wide range of viral factors to attenuate both innate anti-viral pathways and immune cell killing. In this review, we summarize the strategies of oncolytic adenoviruses currently in clinical trials, and speculate how the mutational backgrounds of these viruses may impact upon the efficacy of these agents in oncolytic and immunotherapy. Despite decades of research on human adenoviruses, the interactions that these viruses have with the immune system remains one of the most understudied aspects of the virus and needs to be improved to rationally design the next generation of engineered viruses.

The Challenges and Prospects of p53-Based Therapies in Ovarian Cancer

It has been well established that mutations in the tumor suppressor gene, p53, occur readily in a vast majority of cancer tumors, including ovarian cancer. Typically diagnosed in stages three or four, ovarian cancer is the fifth leading cause of death in women, despite accounting for only 2.5% of all female malignancies. The overall 5-year survival rate for ovarian cancer is around 47%; however, this drops to an abysmal 29% for the most common type of ovarian cancer, high-grade serous ovarian carcinoma (HGSOC). HGSOC has upwards of 96% of cases expressing mutations in p53. Therefore, wild-type (WT) p53 and p53-based therapies have been explored as treatment options via a plethora of drug delivery vehicles including nanoparticles, viruses, polymers, and liposomes. However, previous p53 therapeutics have faced many challenges, which have resulted in their limited translational success to date. This review highlights a selection of these historical p53-targeted therapeutics for ovarian cancer, why they failed, and what the future could hold for a new generation of this class of therapies.

Full Remission of CAR-Deficient Tumors by DOTAP-Folate Liposome Encapsulation of Adenovirus

Adenovirus (Ad)-based vectors have shown considerable promise for gene therapy. However, Ad requires the coxsackievirus and adenovirus receptor (CAR) to enter cells efficiently and low CAR expression is found in many human cancers, which hinder adenoviral gene therapies. Here, cationic 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP)-folate liposomes (Df) encapsulating replication-deficient Ad were synthesized, which showed improved transfection efficiency in various CAR-deficient cell lines, including epithelial and hematopoietic cell types. When encapsulating replication-competent oncolytic Ad (TAV255) in DOTAP-folate liposome (TAV255-Df), the adenoviral structural protein, hexon, was readily produced in CAR-deficient cells, and the tumor cell killing ability was 5× higher than that of the non-encapsulated Ad. In CAR-deficient CT26 colon carcinoma murine models, replication-competent TAV255-Df treatment of subcutaneous tumors by intratumoral injection resulted in 67% full tumor remission, prolonged survival, and anti-cancer immunity when mice were rechallenged with cancer cells with no further treatment. The preclinical data shows that DOTAP-folate liposomes could significantly enhance the transfection efficiency of Ad in CAR-deficient cells and, therefore, could be a feasible strategy for applications in cancer treatment.

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.

Oncolytic virus: A catalyst for the treatment of gastric cancer

Gastric cancer (GC) is a leading contributor to global cancer incidence and mortality. According to the GLOBOCAN 2020 estimates of incidence and mortality for 36 cancers in 185 countries produced by the International Agency for Research on Cancer (IARC), GC ranks fifth and fourth, respectively, and seriously threatens the survival and health of people all over the world. Therefore, how to effectively treat GC has become an urgent problem for medical personnel and scientific workers at this stage. Due to the unobvious early symptoms and the influence of some adverse factors such as tumor heterogeneity and low immunogenicity, patients with advanced gastric cancer (AGC) cannot benefit significantly from treatments such as radical surgical resection, radiotherapy, chemotherapy, and targeted therapy. As an emerging cancer immunotherapy, oncolytic virotherapies (OVTs) can not only selectively lyse cancer cells, but also induce a systemic antitumor immune response. This unique ability to turn unresponsive 'cold' tumors into responsive 'hot' tumors gives them great potential in GC therapy. This review integrates most experimental studies and clinical trials of various oncolytic viruses (OVs) in the diagnosis and treatment of GC. It also exhaustively introduces the concrete mechanism of invading GC cells and the viral genome composition of adenovirus and herpes simplex virus type 1 (HSV-1). At the end of the article, some prospects are put forward to determine the developmental directions of OVTs for GC in the future.

Development of Adenovirus Containing Liposomes Produced by Extrusion vs. Homogenization: A Comparison for Scale-Up Purposes

Adenovirus (Ad) is a widely studied viral vector for cancer therapy as it can be engineered to cause selective lysis of cancer cells. However, Ad delivery is limited in treating cancers that do not have coxsackievirus and adenovirus receptors (CAR). To overcome this challenge, Ad-encapsulated liposomes were developed that enhance the delivery of Ads and increase therapeutic efficacy. Cationic empty liposomes were manufactured first, to which an anionic Ad were added, which resulted in encapsulated Ad liposomes through charge interaction. Optimization of the liposome formula was carried out with series of formulation variables experiments using an extrusion process, which is ideal for laboratory-scale small batches. Later, the optimized formulation was manufactured with a homogenization technique-A high shear rotor-stator blending, that is ideal for large-scale manufacturing and is in compliance with Good Manufacturing Practices (GMP). Comparative in vitro transduction, physicochemical characterization, long-term storage stability at different temperature conditions, and in vivo animal studies were performed. Ad encapsulated liposomes transduced CAR deficient cells 100-fold more efficiently than the unencapsulated Ad (p ≤ 0.0001) in vitro, and 4-fold higher in tumors injected in nude mice in vivo. Both extrusion and homogenization performed similarly-with equivalent in vitro and in vivo transduction efficiencies, physicochemical characterization, and long-term storage stability. Thus, two Ad encapsulated liposomes preparation methods used herein, i.e., extrusion vs. homogenization were equivalent in terms of enhanced Ad performance and long-term storage stability; this will, hopefully, facilitate translation to the clinic.

Current clinical landscape of oncolytic viruses as novel cancer immunotherapeutic and recent preclinical advancements

Oncolytic viruses (OVs) have been gaining attention in the pharmaceutical industry as a novel immunotherapeutic and therapeutic adjuvant due to their ability to induce and boost antitumor immunity through multiple mechanisms. First, intrinsic mechanisms of OVs that enable exploitation of the host immune system (e.g., evading immune detection) can nullify the immune escape mechanism of tumors. Second, many types of OVs have been shown to cause direct lysis of tumor cells, resulting in an induction of tumor-specific T cell response mediated by release of tumor-associated antigens and danger signal molecules. Third, armed OV-expressing immune stimulatory therapeutic genes could be highly expressed in tumor tissues to further improve antitumor immunity. Last, these OVs can inflame cold tumors and their microenvironment to be more immunologically favorable for other immunotherapeutics. Due to these unique characteristics, OVs have been tested as an adjuvant of choice in a variety of therapeutics. In light of these promising attributes of OVs in the immune-oncology field, the present review will examine OVs in clinical development and discuss various strategies that are being explored in preclinical stages for the next generation of OVs that are optimized for immunotherapy applications.

A pH- and Bioreducible Cationic Copolymer with Amino Acids and Piperazines for Adenovirus Delivery

Adenoviruses (Ads) are attractive nonviral vectors and show great potential in cancer gene therapy. However, inherent properties of Ads, including immunogenicity, nonspecific toxicity, and coxsackie and adenovirus receptor (CAR)-dependent cell uptake, limit their clinical use. To surmount these issues, we developed a pH- and glutathione-responsive poly(ethylene glycol)-poly(ꞵ-aminoester)-polyethyleneimine (PPA) for conjugation with Ad. The pH sensitivity of the PPA copolymer was elegantly tuned by substitution with different amino acids (arginine, histidine, and tryptophan), piperazines (Pip1, Pip2, and Pip3), and guanidine residues in the backbone of the PPA conjugate. PPA copolymer was further functionalized with short-chain cross-linker succinimidyl 3-(2-pyridyldithio)propionate) (SPDP) to obtain PPA-SPDP for facile conjugation with Ad. The PPA-conjugated Ad (PPA-Ad) conjugate was obtained by reacting PPA-SPDP conjugate with thiolated Ad (Ad-SH). Ad-SH was prepared by reacting Ad with 2-iminothiolane. The size distribution and zeta potential results of PPA-Ad conjugate showed an increasing trend with an increase in copolymer dose. From in vitro test, it was found that the transduction efficiency of PPA-Ad conjugate in CAR-positive cells (A549 and H460 cells) was remarkably increased at the acidic pH condition (pH 6.2) when compared with PPA-Ad conjugate incubated under the physiological condition (pH 7.4). Interestingly, the increase in transduction efficiency was evidenced in CAR-negative cells (MDA-MB-231 and T24 cells). These results demonstrated that biocompatible and biodegradable PPA copolymers can efficiently cover the surface of Ad and can increase the transduction efficiency, and hence PPA copolymers can be a useful nanomaterial for viral vector delivery in cancer therapy.

γδ T cell costimulatory ligands in antitumor immunity

Antitumor immunity relies on the ability of T cells to recognize and kill tumor targets. γδ T cells are a specialized subset of T cells that predominantly localizes to non-lymphoid tissue such as the skin, gut, and lung where they are actively involved in tumor immunosurveillance. γδ T cells respond to self-stress ligands that are increased on many tumor cells, and these interactions provide costimulatory signals that promote their activation and cytotoxicity. This review will cover costimulatory molecules that are known to be critical for the function of γδ T cells with a specific focus on mouse dendritic epidermal T cells (DETC). DETC are a prototypic tissue-resident γδ T cell population with known roles in antitumor immunity and are therefore useful for identifying mechanisms that may control activation of other γδ T cell subsets within non-lymphoid tissues. This review concludes with a brief discussion on how γδ T cell costimulatory molecules can be targeted for improved cancer immunotherapy.

CAR Co-Operates With Integrins to Promote Lung Cancer Cell Adhesion and Invasion

The coxsackie and adenovirus receptor (CAR) is a member of the junctional adhesion molecule (JAM) family of adhesion receptors and is localised to epithelial cell tight and adherens junctions. CAR has been shown to be highly expressed in lung cancer where it is proposed to promote tumor growth and regulate epithelial mesenchymal transition (EMT), however the potential role of CAR in lung cancer metastasis remains poorly understood. To better understand the role of this receptor in tumor progression, we manipulated CAR expression in both epithelial-like and mesenchymal-like lung cancer cells. In both cases, CAR overexpression promoted tumor growth in vivo in immunocompetent mice and increased cell adhesion in the lung after intravenous injection without altering the EMT properties of each cell line. Overexpression of WTCAR resulted in increased invasion in 3D models and enhanced β1 integrin activity in both cell lines, and this was dependent on phosphorylation of the CAR cytoplasmic tail. Furthermore, phosphorylation of CAR was enhanced by substrate stiffness in vitro, and CAR expression increased at the boundary of solid tumors in vivo. Moreover, CAR formed a complex with the focal adhesion proteins Src, Focal Adhesion Kinase (FAK) and paxillin and promoted activation of the Guanine Triphosphate (GTP)-ase Ras-related Protein 1 (Rap1), which in turn mediated enhanced integrin activation. Taken together, our data demonstrate that CAR contributes to lung cancer metastasis via promotion of cell-matrix adhesion, providing new insight into co-operation between cell-cell and cell-matrix proteins that regulate different steps of tumorigenesis.

Coating an adenovirus with functionalized gold nanoparticles favors uptake, intracellular trafficking and anti-cancer therapeutic efficacy

Adenoviral (Ad) vectors have proven to be important tools for gene and cell therapy, although some issues still need to be addressed, such as undesired interactions with blood components and off-target sequestration that ultimately hamper efficacy. In the past years, several organic and inorganic materials have been developed to reduce immunogenicity and improve biodistribution of Ad vectors. Here we investigated the influence of the functionalization of 14 nm PEGylated gold nanoparticles (AuNPs) with quaternary ammonium groups and an arginine-glycine-aspartic acid (RGD)-motif on the uptake and biodistribution of Ad vectors. We report the formation of Ad@AuNPs complexes that promote cell attachment and uptake, independently of the presence of the coxsackievirus and adenovirus receptor (CAR) and α_vβ₃ and α_vβ₅ integrins, significantly improving transduction without limiting Ad bioactivity. Besides, the presence of the RGD peptide favors tumor targeting and decreases Ad sequestration in the liver. Additionally, tumor delivery of a coated Ad vector expressing the human sodium iodide symporter (hNIS) by mesenchymal stem cells induces increased accumulation of radioactive iodine (¹³¹I) and tumor volume reduction compared to naked Ad-hNIS, highlighting the promising potential of our coating formulation in cancer gene therapy. STATEMENT OF SIGNIFICANCE: Modification of adenoviral vectors with lipids and polymers can reduce interactions with blood components and increase tumor accumulation; however, increased toxicity and reduced transduction efficiency were indicated. Coating with gold nanoparticles has proven to be a successful strategy for increasing the efficiency of transduction of receptor-defective cell lines. Here we explore the contribution of cell surface receptors on the mechanisms of entry of Ad vectors coated with gold nanoparticles in cell lines with varying degrees of resistance to infection. The enhancement of the anti-tumoral effect shown in this work provides new evidence for the potential of our formulation.

JAML promotes CD8 and γδ T cell antitumor immunity and is a novel target for cancer immunotherapy

T cells are critical mediators of antitumor immunity and a major target for cancer immunotherapy. Antibody blockade of inhibitory receptors such as PD-1 can partially restore the activity of tumor-infiltrating lymphocytes (TILs). However, the activation signals required to promote TIL responses are less well characterized. Here we show that the antitumor activity of CD8 and γδ TIL is supported by interactions between junctional adhesion molecule-like protein (JAML) on T cells and its ligand coxsackie and adenovirus receptor (CXADR) within tumor tissue. Loss of JAML through knockout in mice resulted in accelerated tumor growth that was associated with an impaired γδ TIL response and increased CD8 TIL dysfunction. In mouse tumor models, therapeutic treatment with an agonistic anti-JAML antibody inhibited tumor growth, improved γδ TIL activation, decreased markers of CD8 TIL dysfunction, and significantly improved response to anti-PD-1 checkpoint blockade. Thus, JAML represents a novel therapeutic target to enhance both CD8 and γδ TIL immunity.

Coxsackievirus B3-Its Potential as an Oncolytic Virus

Oncolytic virotherapy represents one of the most advanced strategies to treat otherwise untreatable types of cancer. Despite encouraging developments in recent years, the limited fraction of patients responding to therapy has demonstrated the need to search for new suitable viruses. Coxsackievirus B3 (CVB3) is a promising novel candidate with particularly valuable features. Its entry receptor, the coxsackievirus and adenovirus receptor (CAR), and heparan sulfate, which is used for cellular entry by some CVB3 variants, are highly expressed on various cancer types. Consequently, CVB3 has broad anti-tumor activity, as shown in various xenograft and syngeneic mouse tumor models. In addition to direct tumor cell killing the virus induces a strong immune response against the tumor, which contributes to a substantial increase in the efficiency of the treatment. The toxicity of oncolytic CVB3 in healthy tissues is variable and depends on the virus strain. It can be abrogated by genetic engineering the virus with target sites of microRNAs. In this review, we present an overview of the current status of the development of CVB3 as an oncolytic virus and outline which steps still need to be accomplished to develop CVB3 as a therapeutic agent for clinical use in cancer treatment.

CXCL12 Retargeting of an Oncolytic Adenovirus Vector to the Chemokine CXCR4 and CXCR7 Receptors in Breast Cancer

Breast cancer is the most frequently diagnosed cancer in women under 60, and the second most diagnosed cancer in women over 60. While significant progress has been made in developing targeted therapies for breast cancer, advanced breast cancer continues to have high mortality, with poor 5-year survival rates. Thus, current therapies are insufficient in treating advanced stages of breast cancer; new treatments are sorely needed to address the complexity of advanced-stage breast cancer. Oncolytic virotherapy has been explored as a therapeutic approach capable of systemic administration, targeting cancer cells, and sparing normal tissue. In particular, oncolytic adenoviruses have been exploited as viral vectors due to their ease of manipulation, production, and demonstrated clinical safety profile. In this study, we engineered an oncolytic adenovirus to target the chemokine receptors CXCR4 and CXCR7. The overexpression of CXCR4 and CXCR7 is implicated in the initiation, survival, progress, and metastasis of breast cancer. Both receptors bind to the ligand, CXCL12 (SDF-1), which has been identified to play a crucial role in the metastasis of breast cancer cells. This study incorporated a T4 fibritin protein fused to CXCL12 into the tail domain of an adenovirus fiber to retarget the vector to the CXCR4 and CXCR7 chemokine receptors. We showed that the modified virus targets and infects CXCR4- and CXCR7-overexpressing breast cancer cells more efficiently than a wild-type control vector. In addition, the substitution of the wild-type fiber and knob with the modified chimeric fiber did not interfere with oncolytic capability. Overall, the results of this study demonstrate the feasibility of retargeting adenovirus vectors to chemokine receptor-positive tumors.

Toll-like receptors (TLRs) in cancer; with an extensive focus on TLR agonists and antagonists

At the forefront of the battle against pathogens or any endogenously released molecules, toll-like receptors (TLRs) play an important role as the most noble pattern recognition receptors. The ability of these receptors in distinguishing "self" and "non-self" antigens is a cornerstone in the innate immunity system; however, misregulation links inflammatory responses to the development of human cancers. It has been known for some time that aberrant expression and regulation of TLRs not only endows cancer cells an opportunity to escape from the immune system but also supports them through enhancing proliferation and angiogenesis. Over the past decades, cancer research studies have witnessed a number of preclinical and clinical breakthroughs in the field of TLR modulators and some of the agents have exceptionally performed well in advanced clinical trials. In the present review, we have provided a comprehensive review of different TLR agonists and antagonists and discuss their limitations, toxicities, and challenges to outline their future incorporation in cancer treatment strategies.

Co-Expression of Coxsackievirus/Adenovirus Receptors and Desmoglein 2 in Lung Adenocarcinoma: A Comprehensive Analysis of Bioinformatics and Tissue Microarrays

Introduction: Coxsackievirus/adenovirus receptors (CARs) and desmoglein-2 (DSG2) are similar molecules to adenovirus-based vectors in the cell membrane. They have been found to be associated with lung epithelial cell tumorigenesis and can be useful markers in predicting survival outcome in lung adenocarcinoma (LUAD). Methods: A gene ontology enrichment analysis disclosed that DSG2 was highly correlated with CAR. Survival analysis was then performed on 262 samples from the Cancer Genome Atlas, forming “Stage 1A” or “Stage 1B”. We therefore analyzed a tissue microarray (TMA) comprised of 108 lung samples and an immunohistochemical assay. Computer counting software was used to calculate the H-score of the immune intensity. Cox regression and Kaplan–Meier analyses were used to determine the prognostic value. Results: CAR and DSG2 genes are highly co-expressed in early stage LUAD and associated with significantly poorer survival (p = 0.0046). TMA also showed that CAR/DSG2 expressions were altered in lung cancer tissue. CAR in the TMA was correlated with proliferation, apoptosis, and epithelial–mesenchymal transition (EMT), while DSG2 was associated with proliferation only. The Kaplan–Meier survival analysis revealed that CAR, DSG2, or a co-expression of CAR/DSG2 was associated with poorer overall survival. Conclusions: The co-expression of CAR/DSG2 predicted a worse overall survival in LUAD. CAR combined with DSG2 expression can predict prognosis.

Combination of rAd-p53 in situ gene therapy and anti-PD-1 antibody immunotherapy induced anti-tumor activity in mouse syngeneic urogenital cancer models

In this study we undertook a novel combination therapy using rAd-p53 in situ gene therapy and immunotherapy with immune checkpoint inhibitor (ICI) anti-PD-1 antibody for urogenital cancers. Three mouse syngeneic tumor cell lines, TRAMP-C2 (prostate cancer derived from C57BL/6 mice), MBT-2 (bladder cancer derived from C3H mice) and Renca (kidney cancer derived from BALB/c mice) were used in this study. The highest coxsackie and adenovirus receptor (CAR) mRNA expression was observed in TRAMP-C2 cells, followed by Renca and then MBT-2 cells. Consistent with the CAR expressions, rAd-p53 at 160 multiplicity of infection (MOI) significantly inhibited the cell proliferation of TRAMP-C2 and Renca cells, but not MBT-2 cells. In in vivo experiments, the combination of intratumoral injections of rAd-p53 (1 × 10⁹ plaque-forming units) every other day and intraperitoneal injections of anti-mouse PD-1 antibody (200 μg) twice a week suppressed tumor growth and prolonged survival compared to rAd-p53 or anti-PD-1 antibody monotherapy in both the TRAMP-C2 and Renca models. Our results encourage the clinical development of combination therapy comprised of in situ gene therapy with rAd-p53 and immunotherapy with an ICI anti-PD-1 antibody for urogenital cancers.

Adenovirus Receptor Expression in Cancer and Its Multifaceted Role in Oncolytic Adenovirus Therapy

Oncolytic adenovirus therapy is believed to be a promising way to treat cancer patients. To be able to target tumor cells with an oncolytic adenovirus, expression of the adenovirus receptor on the tumor cell is essential. Different adenovirus types bind to different receptors on the cell, of which the expression can vary between tumor types. Pre-existing neutralizing immunity to human adenovirus species C type 5 (HAdV-C5) has hampered its therapeutic efficacy in clinical trials, hence several adenoviral vectors from different species are currently being developed as a means to evade pre-existing immunity. Therefore, knowledge on the expression of appropriate adenovirus receptors on tumor cells is important. This could aid in determining which tumor types would benefit most from treatment with a certain oncolytic adenovirus type. This review provides an overview of the known receptors for human adenoviruses and how their expression on tumor cells might be differentially regulated compared to healthy tissue, before and after standardized anticancer treatments. Mechanisms behind the up- or downregulation of adenovirus receptor expression are discussed, which could be used to find new targets for combination therapy to enhance the efficacy of oncolytic adenovirus therapy. Additionally, the utility of the adenovirus receptors in oncolytic virotherapy is examined, including their role in viral spread, which might even surpass their function as primary entry receptors. Finally, future directions are offered regarding the selection of adenovirus types to be used in oncolytic adenovirus therapy in the fight against cancer.

Transient Chimeric Ad5/37 Fiber Enhances NK-92 Carrier Cell-Mediated Delivery of Oncolytic Adenovirus Type 5 to Tumor Cells

Methods for customizing and improving virus vector tropism are limited. In this study, we introduce a microRNA (miRNA)-regulated molecular method to enhance vector transduction without genome alteration. Based on the importance of adenovirus (Ad) vectors for cancer and gene treatment, we exemplified this technology for an Ad type 5 (Ad5) vector temporally carrying a knob from Ad37. We constructed a producer cell line stably expressing a fused Ad5/37 chimeric fiber comprising the Ad5 shaft-tail and the Ad37 knob and a miRNA inhibiting Ad5 knob expression (HEK293-Ad5/37-miRNA). The chimeric Ad5/37 vector resulted in enhanced transduction rates in Ad37 adequately and Ad5 poorly transduced cells. Particularly, encapsidation of the oncolytic Ad5-human telomerase reverse transcriptase (hTERT) vector genome into the chimeric Ad5/37 capsid showed efficient transduction of NK-92 carrier cells. These infected carrier cells then delivered the oncolytic vector to tumor cells, which resulted in enhanced Ad5-hTERT-mediated tumor cell killing. We show that this transiently capsid-modified chimeric vector carrying an Ad5 genome displayed higher transduction efficiencies of natural killer cell-derived NK-92 cells utilized as carriers in cancer immune therapy. In summary, transiently modified adenoviral vectors will have important implications for cancer and gene therapy.

Therapeutic targeting of the RB1 pathway in retinoblastoma with the oncolytic adenovirus VCN-01

Retinoblastoma is a pediatric solid tumor of the retina activated upon homozygous inactivation of the tumor suppressor RB1 VCN-01 is an oncolytic adenovirus designed to replicate selectively in tumor cells with high abundance of free E2F-1, a consequence of a dysfunctional RB1 pathway. Thus, we reasoned that VCN-01 could provide targeted therapeutic activity against even chemoresistant retinoblastoma. In vitro, VCN-01 effectively killed patient-derived retinoblastoma models. In mice, intravitreous administration of VCN-01 in retinoblastoma xenografts induced tumor necrosis, improved ocular survival compared with standard-of-care chemotherapy, and prevented micrometastatic dissemination into the brain. In juvenile immunocompetent rabbits, VCN-01 did not replicate in retinas, induced minor local side effects, and only leaked slightly and for a short time into the blood. Initial phase 1 data in patients showed the feasibility of the administration of intravitreous VCN-01 and resulted in antitumor activity in retinoblastoma vitreous seeds and evidence of viral replication markers in tumor cells. The treatment caused local vitreous inflammation but no systemic complications. Thus, oncolytic adenoviruses targeting RB1 might provide a tumor-selective and chemotherapy-independent treatment option for retinoblastoma.

Cell Surface Proteins in Hepatocellular Carcinoma: From Bench to Bedside

Cell surface proteins act as the go-between in carrying the information from the extracellular environment to the intracellular signaling proteins. However, these proteins are often deregulated in neoplastic diseases, including hepatocellular carcinoma. This review discusses several recent studies that have investigated the role of cell surface proteins in the occurrence and progression of HCC, highlighting the possibility to use them as biomarkers of the disease and/or targets for vaccines and therapeutics.

Virus-Receptor Interactions: Structural Insights For Oncolytic Virus Development

Recent advancements in oncolytic virotherapy commend a special attention to developing new strategies for targeting cancer cells with oncolytic viruses (OVs). Modifications of the viral envelope or coat proteins serve as a logical mean of repurposing viruses for cancer treatment. In this review, we discuss how detailed structural knowledge of the interactions between OVs and their natural receptors provide valuable insights into tumor specificity of some viruses and re-targeting of alternate receptors for broad tumor tropism or improved tumor selectivity.

Preclinical And Clinical Development Of Oncolytic Adenovirus For The Treatment Of Malignant Glioma

Replication conditional oncolytic human adenovirus has long been considered a promising biological therapeutic to target high-grade gliomas (HGG), a group of essentially lethal primary brain cancer. The last decade has witnessed initiation and some completion of a number of Phase I and II clinical investigations of oncolytic adenovirus for HGG in the US and Europe. Results of these trials in patients are pivotal for not only federal approval but also filling an existing knowledge gap that primarily derives from the stark differences in permissivity to human adenovirus between humans and preclinical mouse models. DNX-2401 (Delta-24-RGD), the current mainstream oncolytic adenovirus with modifications in E1A and the fiber, has been shown to induce impressive objective response and long-term survival (>3 years) in a fraction of patients with recurrent HGG. Responders exhibited initial enlargement of the treated lesions for a few months post treatment, followed by shrinkage and near complete resolution. In accord with preclinical research, post-treatment specimens revealed virus-mediated alteration of the immune tumor microenvironment as evidenced by infiltration of CD8+ T cells and M1-polarized macrophages. These findings are encouraging and together with further information from ongoing studies have a potential to make oncolytic adenovirus a viable option for clinical management of HGG. This review deals with this timely topic; we will describe both preclinical and clinical development of oncolytic adenovirus therapy for HGG, summarize updated knowledge on clinical trials and discuss challenges that the field currently faces.

Expression and clinicopathologic significance of coxsackie-adenovirus receptor in oral squamous cell carcinoma

OBJECTIVE

This study aimed to explore the relationship between the expression of the coxsackie-adenovirus receptor (CAR) in oral squamous cell carcinoma (OSCC) and the clinicopathologic parameters associated with the disease. The diagnostic and prognostic potential of CAR in OSCC was also investigated.

STUDY DESIGN

Immunohistochemistry was performed on human tissue microarrays, containing 42 oral mucosa, 69 dysplasia, and 176 OSCC tissue sections, to reveal the expression pattern of CAR. Statistical analysis was used to determine the correlation between CAR expression and the patient survival rate as a measure of the prognostic value of CAR.

RESULTS

CAR was overexpressed in human OSCC tissues (P = .002), and higher expression of CAR was associated with a lower survival rate, which was not statistically significant (P = .123). In addition, patients with OSCC in the human papillomavirus (HPV)-positive group showed significantly higher CAR expression compared with the HPV- negative group (P = .0491).

CONCLUSIONS

This study indicated that CAR expression was upregulated in human OSCC and that patients with OSCC with higher expression of CAR had a lower survival rate. Moreover, CAR expression may be associated with HPV infection.

The TRAIL to cancer therapy: Hindrances and potential solutions

Apoptosis is an ordered and orchestrated cellular process that occurs in physiological and pathological conditions. Resistance to apoptosis is a hallmark of virtually all malignancies. Despite being a cause of pathological conditions, apoptosis could be a promising target in cancer treatment. Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL), also known as Apo-2 ligand (Apo2L), is a member of TNF cytokine superfamily. It is a potent anti-cancer agent owing to its specific targeting towards cancerous cells, while sparing normal cells, to induce apoptosis. However, resistance occurs either intrinsically or after multiple treatments which may explain why cancer therapy fails. This review summarizes the apoptotic mechanisms via extrinsic and intrinsic apoptotic pathways, as well as the apoptotic resistance mechanisms. It also reviews the current clinically tested recombinant human TRAIL (rhTRAIL) and TRAIL receptor agonists (TRAs) against TRAIL-Receptors, TRAIL-R1 and TRAIL-R2, in which the outcomes of the clinical trials have not been satisfactory. Finally, this review discusses the current strategies in overcoming resistance to TRAIL-induced apoptosis in pre-clinical and clinical settings.

The Utilization of Cell-Penetrating Peptides in the Intracellular Delivery of Viral Nanoparticles

Viral particles (VPs) have evolved so as to efficiently enter target cells and to deliver their genetic material. The current state of knowledge allows us to use VPs in the field of biomedicine as nanoparticles that are safe, easy to manipulate, inherently biocompatible, biodegradable, and capable of transporting various cargoes into specific cells. Despite the fact that these virus-based nanoparticles constitute the most common vectors used in clinical practice, the need remains for further improvement in this area. The aim of this review is to discuss the potential for enhancing the efficiency and versatility of VPs via their functionalization with cell-penetrating peptides (CPPs), short peptides that are able to translocate across cellular membranes and to transport various substances with them. The review provides and describes various examples of and means of exploitation of CPPs in order to enhance the delivery of VPs into permissive cells and/or to allow them to enter a broad range of cell types. Moreover, it is possible that CPPs are capable of changing the immunogenic properties of VPs, which could lead to an improvement in their clinical application. The review also discusses strategies aimed at the modification of VPs by CPPs so as to create a useful cargo delivery tool.

Oncolytic viro-chemotherapy exhibits antitumor effect in laryngeal squamous cell carcinoma cells and mouse xenografts

Background: Oncolytic virus can specifically replicate in and then lyse tumor cells, but seldom in normal cells. Further studies have shown the significant therapeutic effect of oncolytic virotherapy combining with other strategies, such as chemo-, radio-, and immunotherapy et al. In this study, we investigated the combinational effect of oncolytic virus ZD55-TRAIL and chemotherapy drug doxorubicin (DOX) on human laryngeal squamous cell carcinoma (LSCC).

Methods: The effect of ZD55-TRAIL combined with DOX on cell growth was assessed in LSCC Hep2 cells and normal cells by MTT assay. Hochest 33342 staining was performed to observe cell morphological changes. Western blot was used to detect the expression of apoptotic activation proteins. The in vivo antitumor efficacy of combination treatment was estimated in laryngeal cancer xenograft models.

Results: The combination of ZD55-TRAIL and DOX exhibited enhanced inhibitory effects on laryngocarcinoma cell growth, and had few side effects to normal cells in vitro. Chemotherapy drug increased the inducement of tumor cell apoptosis mediated by oncolytic virus. In vivo experiment confirmed that the combination treatment significantly inhibited Hep2 laryngocarcinoma xenografts growth in mice.

Conclusion: The oncolytic viro-chemotherapy is a potent therapeutic approach for in vitro cytotoxicity evaluation of Hep2 cells and xenograft growth in vivo.

Unleashing the Full Potential of Oncolytic Adenoviruses against Cancer by Applying RNA Interference: The Force Awakens

Oncolytic virus therapy of cancer is an actively pursued field of research. Viruses that were once considered as pathogens threatening the wellbeing of humans and animals alike are with every passing decade more prominently regarded as vehicles for genetic and oncolytic therapies. Oncolytic viruses kill cancer cells, sparing healthy tissues, and provoke an anticancer immune response. Among these viruses, recombinant adenoviruses are particularly attractive agents for oncolytic immunotherapy of cancer. Different approaches are currently examined to maximize their therapeutic effect. Here, knowledge of virus–host interactions may lead the way. In this regard, viral and host microRNAs are of particular interest. In addition, cellular factors inhibiting viral replication or dampening immune responses are being discovered. Therefore, applying RNA interference is an attractive approach to strengthen the anticancer efficacy of oncolytic viruses gaining attention in recent years. RNA interference can be used to fortify the virus’ cancer cell-killing and immune-stimulating properties and to suppress cellular pathways to cripple the tumor. In this review, we discuss different ways of how RNA interference may be utilized to increase the efficacy of oncolytic adenoviruses, to reveal their full potential.

CXADR-Mediated Formation of an AKT Inhibitory Signalosome at Tight Junctions Controls Epithelial-Mesenchymal Plasticity in Breast Cancer

Tight junctions (TJ) act as hubs for intracellular signaling pathways controlling epithelial cell fate and function. Deregulation of TJ is a hallmark of epithelial-mesenchymal transition (EMT), which contributes to carcinoma progression and metastasis. However, the signaling mechanisms linking TJ to the induction of EMT are not understood. Here, we identify a TJ-based signalosome, which controls AKT signaling and EMT in breast cancer. The coxsackie and adenovirus receptor (CXADR), a TJ protein with an essential yet uncharacterized role in organogenesis and tissue homeostasis, was identified as a key component of the signalosome. CXADR regulated the stability and function of the phosphatases and AKT inhibitors PTEN and PHLPP2. Loss of CXADR led to hyperactivation of AKT and sensitized cells to TGFβ1-induced EMT. Conversely, restoration of CXADR stabilized PHLPP2 and PTEN, inhibited AKT, and promoted epithelial differentiation. Loss of CXADR in luminal A breast cancer correlated with loss of PHLPP2 and PTEN and poor prognosis. These results show that CXADR promotes the formation of an AKT-inhibitory signalosome at TJ and regulates epithelial-mesenchymal plasticity in breast cancer cells. Moreover, loss of CXADR might be used as a prognostic marker in luminal breast cancer. SIGNIFICANCE: The tight junction protein CXADR controls epithelial-mesenchymal plasticity in breast cancer by stabilizing the AKT regulators PTEN and PHLPP2.Graphical Abstract: http://cancerres.aacrjournals.org/content/canres/79/1/47/F1.large.jpg.

Tropism and transduction of oncolytic adenovirus 5 vectors in cancer therapy: Focus on fiber chimerism and mosaicism, hexon and pIX

The cellular internalization (infection of cells) of adenovirus 5 (Ad5) is mediated by the initial attachment of the globular knob domain of the capsid fiber protein to the cell surface coxsackievirus and adenovirus receptor (CAR), then followed by the interaction of the virus penton base proteins with cellular integrins. In tumors, there is a substantial intra- and intertumoral variability in CAR expression. The CAR-negative cells generally exhibit very low infectability. Since the fiber knob is a primary mediator of Ad5 binding to the cell surface, improved infectivity of Ad5-based vectors as oncolytic agents may be achieved via genetic modifications of this domain. The strategies to modify or broaden tropism and increase transduction efficiency of Ad5-based vectors include: 1) an incorporation of a targeting peptide into the fiber knob domain (the HI loop and/or C-terminus); 2) fiber knob serotype switching, or pseudotyping, by constructing chimeric fibers consisting of the knob domain derived from an alternate serotype (e.g., Ad5/3 or Ad5/35 chimeras), which binds to receptor(s) other than CAR (e.g., desmoglein 2/DSG2 and/or CD46); 3) "fiber complex mosaicism", an approach of combining serotype chimerism with peptide ligand(s) incorporation (e.g., Ad5/3-RGD); 4) "dual fiber mosaicism" by expressing two separate fibers with distinct receptor-binding capabilities on the same viral particle (e.g., Ad5-5/3 or Ad5-5/σ1); 5) fiber xenotyping by replacing the knob and shaft domains of wild-type Ad5 fiber protein with fibritin trimerization domain of T4 bacteriophage or σ1 attachment protein of reovirus. Other genetic approaches to increase the CAR-independent transduction efficiency include insertion of a targeting peptide into the hypervariable region of the capsid protein hexon or fusion to the C-terminus of pIX. Finally, we consider a yet unsolved molecular mechanism of liver targeting by Ad5-based vectors (CAR-, integrin-, fiber shaft KKTK motif-, and hepatic heparan sulfate glycosaminoglycans-independent, but fiber-, hexon- and blood factor X-dependent).

TLR Agonists as Adjuvants for Cancer Vaccines

Toll-like receptors (TLRs) are one of the best characterised families of pattern recognition receptors (PRRs) and play a critical role in the host defence to infection. Accumulating evidence indicates that TLRs also participate in maintaining tissue homeostasis by controlling inflammation and tissue repair, as well as promoting antitumour effects via activation and modulation of adaptive immune responses. TLR agonists have successfully been exploited to ameliorate the efficacy of various cancer therapies. In this chapter, we will discuss the rationales of using TLR agonists as adjuvants to cancer treatments and summarise the recent findings of preclinical and clinical studies of TLR agonist-based cancer therapies.

CAR: A key regulator of adhesion and inflammation

The coxsackie and adenovirus receptor (CAR) is a transmembrane receptor that plays a key role in controlling adhesion between adjacent epithelial cells. CAR is highly expressed in epithelial cells and was originally identified as a primary receptor for adenovirus cell binding. However, studies over the last 10 years have demonstrated that CAR plays a key role in co-ordinating cell-cell adhesion under homeostatic conditions including neuronal and cardiac development and cell junction stability; it has also been implicated in pathological states such as cancer growth and leukocyte transmigration during inflammation. Here we provide an overview of the functions of CAR as an adhesion molecule and highlight the emerging important role for CAR in controlling both recruitment of immune cells and in tumorigenesis.

Group B adenovirus enadenotucirev infects polarised colorectal cancer cells efficiently from the basolateral surface expected to be encountered during intravenous delivery to treat disseminated cancer

Enadenotucirev (EnAd) is a group B oncolytic adenovirus developed for systemic delivery and currently undergoing clinical evaluation for advanced cancer therapy. For differentiated carcinomas, systemic delivery would likely expose virus particles to the basolateral surface of cancer cells rather than the apical surface encountered during natural infection. Here, we compare the ability of EnAd and adenovirus type-5 (Ad5) to infect polarised colorectal carcinoma cells from the apical or basolateral surfaces. Whereas Ad5 infection was more efficient via the apical than basolateral surface, EnAd readily infected cells from either surface. Progeny particles from EnAd were released preferentially via the apical surface for all cell lines and routes of infection. These data further support the utility of group B adenoviruses for systemic delivery and suggest that progeny virus are more likely to be released into the tumour rather than back through the basolateral surface into the blood stream.

Cell-cell communication mediated by the CAR subgroup of immunoglobulin cell adhesion molecules in health and disease

The immunoglobulin superfamily represents a diverse set of cell-cell contact proteins and includes well-studied members such as NCAM1, DSCAM, L1 or the contactins which are strongly expressed in the nervous system. In this review we put our focus on the biological function of a less understood subgroup of Ig-like proteins composed of CAR (coxsackievirus and adenovirus receptor), CLMP (CAR-like membrane protein) and BT-IgSF (brain and testis specific immunoglobulin superfamily). The CAR-related proteins are type I transmembrane proteins containing an N-terminal variable (V-type) and a membrane proximal constant (C2-type) Ig domain in their extracellular region which are implicated in homotypic adhesion. They are highly expressed during embryonic development in a variety of tissues including the nervous system whereby in adult stages the protein level of CAR and CLMP decreases, only BT-IgSF expression increases within age. CAR-related proteins are concentrated at specialized cell-cell communication sites such as gap or tight junctions and are present at the plasma membrane in larger protein complexes. Considerable progress has been made on the molecular structure and interactions of CAR while research on CLMP and BT-IgSF is at an early stage. Studies on mouse mutants revealed biological functions of CAR in the heart and for CLMP in the gastrointestinal and urogenital systems. Furthermore, CAR and BT-IgSF appear to regulate synaptic function in the hippocampus.

CXCL12 retargeting of an adenovirus vector to cancer cells using a bispecific adapter

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. These receptors have been associated with cancer cell survival, progression, and metastasis. In the current study, an Ad to cancer cells overexpressing CXCR4 by using a bispecific adapter, sCAR-CXCL12, was retargeted. The sCAR-CXCL12 adapter contained the soluble ectodomain form of the native Ad5 receptor (sCAR), which was fused to a mature human chemokine ligand, CXCL12, through a short peptide linker. A dramatic increase in the infectivity of cancer cells using a targeted Ad vector compared with an untargeted vector was observed. Furthermore, sCAR-CXCL12 attenuated Ad infection of liver ex vivo and in vivo and enhanced Ad vector infection of xenograft tumors implanted in immunodeficient SCID-bg mice. Thus, the sCAR-CXCL12 adapter could be used to retarget Ad vectors to chemokine receptor-positive tumors.

Loss of coxsackie and adenovirus receptor expression in human colorectal cancer: A potential impact on the efficacy of adenovirus-mediated gene therapy in Chinese Han population

The coxsackie and adenovirus receptor (CAR) is considered a tumor suppressor and critical factor for the efficacy of therapeutic strategies that employ the adenovirus. However, data on CAR expression levels in colorectal cancer are conflicting and its clinical relevance remains to be elucidated. Immunohistochemistry was performed on tissue microarrays containing 251 pairs of colon cancer and adjacent normal tissue samples from Chinese Han patients to assess the expression levels of CAR. Compared with healthy mucosa, decreased CAR expression (40.6% vs. 95.6%; P<0.001) was observed in colorectal cancer samples. The CAR immunopositivity in tumor tissues was not significantly associated with gender, age, tumor size, differentiation, TNM stage, lymph node metastasis or distant metastasis in patients with colon cancer. However, expression of CAR is present in 83.3% of the tumor tissues from patient with colorectal liver metastasis, which was significantly higher than those without liver metastasis (39.6%; P=0.042). At the plasma membrane, CAR was observed in 29.5% normal mucosa samples, which was significantly higher than in colorectal cancer samples (4.0%; P<0.001). In addition, the survival analysis demonstrated that the expression level of CAR has no association with the prognosis of colorectal cancer. CAR expression was observed to be downregulated in colorectal cancer, and it exerts complex effects during colorectal carcinogenesis, potentially depending on the stage of the cancer development and progression. High CAR expression may promote liver metastasis. With regard to oncolytic therapy, CAR expression analysis should be performed prior to adenoviral oncolytic treatment to stratify Chinese Han patients for treatment.

Arg-Gly-Asp (RGD)-Modified E1A/E1B Double Mutant Adenovirus Enhances Antitumor Activity in Prostate Cancer Cells In Vitro and in Mice

CAR is a transmembrane protein that is expressed in various epithelial and endothelial cells. CAR mediates adenoviral infection, as well as adenovirus-mediated oncolysis of AxdAdB-3, an E1A/E1B double-restricted oncolytic adenovirus, in prostate cancer cells. This study further assessed the therapeutic efficacy of AxdAdB-3 with Arg-Gly-Asp (RGD)-fiber modification (AxdAdB3-F/RGD), which enables integrin-dependent infection, in prostate cancer. Susceptibility of prostate cancer cells LNCaP, PC3, and DU145 to adenovirus infection was associated with CAR expression. All of the prostate cancer cell lines expressed integrin α_vβ₃ and α_vβ₅. AxdAdB-3 was more cytopathic in CAR-positive prostate cancer cells than in CAR-negative cells, whereas AxdAdB3-F/RGD caused potent oncolysis in both CAR-positive and CAR-negative prostate cancer cells. In contrast, AxdAdB3-F/RGD was not cytopathic against normal prostate epithelial cells, RWPE-1. Intratumoral injection of AxdAdB3-F/RGD into CAR-negative prostate cancer cell xenografts in nude mice inhibited tumor growth. The current study demonstrates that E1A/E1B double-restricted oncolytic adenovirus with an RGD-fiber modification enhances infection efficiency and anti-tumor activity in CAR-deficient prostate cancer cells, while sparing normal cells. Future studies will evaluate the therapeutic potential of AxdAdB3-F/RGD in prostate cancer.

TOX3 protein expression is correlated with pathological characteristics in breast cancer

TOX3 is a newly identified gene that has been observed to correlate with breast cancer by genome-wide association studies (GWAS) in recent years. In addition, it has been noted that single-nucleotide polymorphisms (SNPs) in the TOX3 gene have a strong correlation with estrogen receptor (ER)-positive tumors. However, the role of TOX3 in breast carcinoma development is still unclear. There are limited studies on the subject of TOX3 mRNA expression in breast tumors and little information on the variation of TOX3 protein expression in relation to the clinical pathological features in breast cancer and healthy tissues. In this study, we characterize the protein expression of TOX3 in breast tumors with respect to various clinical and pathological characteristics and explore the correlation between TOX3 protein expression and ER-positive tumors. A breast cancer tissue microarray containing 267 human breast tumors and 25 healthy controls, breast cancer cell lines (ZR-75-1, MDA-MB-231, MCF-7 and Bcap-37) with positive or negative ER expression, tumor tissues and matched controls were used to analyze the protein expression levels of TOX3 by immunohistochemistry, western blot analysis and quantitative polymerase chain reaction. Among the 267 breast tumor specimens, ER expression was detected in 66 tumor tissues. The expression levels of TOX3 increased in breast carcinoma tissue compared with controls, and were higher in advanced carcinoma (T3 and T4), lymph node metastases tissues (N2) and stage III tissues. Furthermore, TOX3 protein expression was more intense in ER-positive tumors, but did not demonstrate a statistical significance. However, it was significantly increased in ER-positive breast cancer cell lines (ZR-75-1, MCF-7 and Bcap-37) compared with the MDA-MB-231 cell line, which had ER-negative expression. Our findings provide support to the hypothesis that TOX3 has a strong correlation with the development of breast cancer. The current study is likely to assist in investigating the mechanisms involved in breast cancer development.

Applications of the Keap1-Nrf2 system for gene and cell therapy

Oxidative stress has been implicated to play a role in a number of acute and chronic diseases including acute injuries of the central nervous system, neurodegenerative and cardiovascular diseases, and cancer. The redox-activated transcription factor Nrf2 has been shown to protect many different cell types and organs from a variety of toxic insults, whereas in many cancers, unchecked Nrf2 activity increases the expression of cytoprotective genes and, consequently, provides growth advantage to cancerous cells. Herein, we discuss current preclinical gene therapy approaches to either increase or decrease Nrf2 activity with a special reference to neurological diseases and cancer. In addition, we discuss the role of Nrf2 in stem cell therapy for neurological disorders.

Paradigms lost-an emerging role for over-expression of tight junction adhesion proteins in cancer pathogenesis

Tight junctions (TJ) are multi-protein complexes located at the apicalmost tip of the lateral membrane in polarised epithelial and endothelial cells. Their principal function is in mediating intercellular adhesion and polarity. Accordingly, it has long been a paradigm that loss of TJ proteins and consequent deficits in cell-cell adhesion are required for tumour cell dissemination in the early stages of the invasive/metastatic cascade. However it is becoming increasingly apparent that TJ proteins play important roles in not just adhesion but also intracellular signalling events, activation of which can contribute to, or even drive, tumour progression and metastasis. In this review, we shall therefore highlight cases wherein the gain of TJ proteins has been associated with signals promoting tumour progression. We will also discuss the potential of overexpressed TJ proteins to act as therapeutic targets in cancer treatment. The overall purpose of this review is not to disprove the fact that loss of TJ-based adhesion contributes to the progression of several cancers, but rather to introduce the growing body of evidence that gain of TJ proteins may have adhesion-independent consequences for promoting progression in other cancers.

Differentiation of lung stem/progenitor cells into alveolar pneumocytes and induction of angiogenesis within a 3D gelatin--microbubble scaffold

The inability to adequately vascularize tissues in vitro or in vivo is a major challenge in lung tissue engineering. A method that integrates stem cell research with 3D-scaffold engineering may provide a solution. We have successfully isolated mouse pulmonary stem/progenitor cells (mPSCs) by a two-step procedure and fabricated mPSC-compatible gelatin/microbubble-scaffolds using a 2-channel fluid jacket microfluidic device. We then integrated the cells and the scaffold to construct alveoli-like structures. The mPSCs expressed pro-angiogenic factors (e.g., b-FGF and VEGF) and induced angiogenesis in vitro in an endothelial cell tube formation assay. In addition, the mPSCs were able to proliferate along the inside of the scaffolds and differentiate into type-II and type-I pneumocytes The mPSC-seeded microbubble-scaffolds showed the potential for blood vessel formation in both a chick chorioallantoic membrane (CAM) assay and in experiments for subcutaneous implantation in severe combined immunodeficient (SCID) mice. Our results demonstrate that lung stem/progenitor cells together with gelatin microbubble-scaffolds promote angiogenesis as well as the differentiation of alveolar pneumocytes, resulting in an alveoli-like structure. These findings may help advance lung tissue engineering.