Coxsackievirus and adenovirus receptor expression in non-malignant lung tissues and clinical lung cancers

Utilizing Adenovirus Knob Proteins as Carriers in Cancer Gene Therapy Amidst the Presence of Anti-Knob Antibodies

Numerous gene therapy drugs for cancer have received global approval, yet their efficacy against solid tumors remains inadequate. Our previous research indicated that the fiber protein, a component of the adenovirus capsid, can propagate from infected cells to neighboring cells that express the adenovirus receptor. We hypothesize that merging this fiber protein with an anti-cancer protein could enable the anti-cancer protein to disseminate around the transfected cells, presenting a novel approach to cancer gene therapy. In our study, we discovered that the knob region of the adenovirus type 5 fiber protein is the smallest unit capable of spreading to adjacent cells in a receptor-specific manner. We also showed that the recombinant knob protein infiltrates cells after dispersing to surrounding cells. To assess the potential of the knob protein to augment gene therapy for solid tumors in mice, we expressed a fusion gene of the A subunit of cytotoxic cholera toxin and the knob region in mouse tumors. We found that this fusion protein only inhibited tumor growth in receptor-expressing mouse melanomas, and this inhibitory effect persisted even in mice with anti-knob antibodies. Our study's findings propose a novel cancer gene therapy strategy that enhances therapeutic effects by specifically delivering therapeutic proteins, expressed from in vivo administered genes, to target molecules. This outcome offers a fresh perspective on gene therapy for solid cancers, and we anticipate that knob proteins will serve as a platform for this method.

Receptors and Host Factors for Enterovirus Infection: Implications for Cancer Therapy

Enteroviruses, with their diverse clinical manifestations ranging from mild or asymptomatic infections to severe diseases such as poliomyelitis and viral myocarditis, present a public health threat. However, they can also be used as oncolytic agents. This review shows the intricate relationship between enteroviruses and host cell factors. Enteroviruses utilize specific receptors and coreceptors for cell entry that are critical for infection and subsequent viral replication. These receptors, many of which are glycoproteins, facilitate virus binding, capsid destabilization, and internalization into cells, and their expression defines virus tropism towards various types of cells. Since enteroviruses can exploit different receptors, they have high oncolytic potential for personalized cancer therapy, as exemplified by the antitumor activity of certain enterovirus strains including the bioselected non-pathogenic Echovirus type 7/Rigvir, approved for melanoma treatment. Dissecting the roles of individual receptors in the entry of enteroviruses can provide valuable insights into their potential in cancer therapy. This review discusses the application of gene-targeting techniques such as CRISPR/Cas9 technology to investigate the impact of the loss of a particular receptor on the attachment of the virus and its subsequent internalization. It also summarizes the data on their expression in various types of cancer. By understanding how enteroviruses interact with specific cellular receptors, researchers can develop more effective regimens of treatment, offering hope for more targeted and efficient therapeutic strategies.

Non-small cell lung cancers (NSCLCs) oncolysis using coxsackievirus B5 and synergistic DNA-damage response inhibitors

With the continuous in-depth study of the interaction mechanism between viruses and hosts, the virus has become a promising tool in cancer treatment. In fact, many oncolytic viruses with selectivity and effectiveness have been used in cancer therapy. Human enterovirus is one of the most convenient sources to generate oncolytic viruses, however, the high seroprevalence of some enteroviruses limits its application which urges to exploit more oncolytic enteroviruses. In this study, coxsackievirus B5/Faulkner (CV-B5/F) was screened for its potential oncolytic effect against non-small cell lung cancers (NSCLCs) through inducing apoptosis and autophagy. For refractory NSCLCs, DNA-dependent protein kinase (DNA-PK) or ataxia telangiectasia mutated protein (ATM) inhibitors can synergize with CV-B5/F to promote refractory cell death. Here, we showed that viral infection triggered endoplasmic reticulum (ER) stress-related pro-apoptosis and autophagy signals, whereas repair for double-stranded DNA breaks (DSBs) contributed to cell survival which can be antagonized by inhibitor-induced cell death, manifesting exacerbated DSBs, apoptosis, and autophagy. Mechanistically, PERK pathway was activated by the combination of CV-B5/F and inhibitor, and the irreversible ER stress-induced exacerbated cell death. Furthermore, the degradation of activated STING by ERphagy promoted viral replication. Meanwhile, no treatment-related deaths due to CV-B5/F and/or inhibitors occurred. Conclusively, our study identifies an oncolytic CV-B5/F and the synergistic effects of inhibitors of DNA-PK or ATM, which is a potential therapy for NSCLCs.

The Coxsackievirus and Adenovirus Receptor Has a Short Half-Life in Epithelial Cells

The coxsackievirus and adenovirus receptor (CAR) is an essential cellular protein that is involved in cell adhesion, cell signaling, and viral infection. The 8-exon encoded isoform (CAREx8) resides at the apical surface of polarized epithelia, where it is accessible as a receptor for adenovirus entering the airway lumen. Given its pivotal role in viral infection, it is a target for antiviral strategies. To understand the regulation of CAREx8 and determine the feasibility of receptor downregulation, the half-life of total and apical localized CAREx8 was determined and correlated with adenovirus transduction. Total and apical CAREx8 has a relatively short half-life of approximately 2 h. The half-life of apical CAREx8 correlates well with adenovirus transduction. These results suggest that antiviral strategies that aim to degrade the primary receptor for apical adenovirus infection will be effective within a relatively short time frame after application.

Development of Group B Coxsackievirus as an Oncolytic Virus: Opportunities and Challenges

Oncolytic viruses have emerged as a promising strategy for cancer therapy due to their dual ability to selectively infect and lyse tumor cells and to induce systemic anti-tumor immunity. Among various candidate viruses, coxsackievirus group B (CVBs) have attracted increasing attention in recent years. CVBs are a group of small, non-enveloped, single-stranded, positive-sense RNA viruses, belonging to species human Enterovirus B in the genus Enterovirus of the family Picornaviridae. Preclinical studies have demonstrated potent anti-tumor activities for CVBs, particularly type 3, against multiple cancer types, including lung, breast, and colorectal cancer. Various approaches have been proposed or applied to enhance the safety and specificity of CVBs towards tumor cells and to further increase their anti-tumor efficacy. This review summarizes current knowledge and strategies for developing CVBs as oncolytic viruses for cancer virotherapy. The challenges arising from these studies and future prospects are also discussed in this review.

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.

Generation and evaluation of a chimeric antibody against coxsackievirus and adenovirus receptor for cancer therapy

Coxsackievirus and adenovirus receptor (CAR) is a single-pass transmembrane protein that is associated with adenoviral infection. CAR is involved in the formation of epithelial tight junctions and promotes tumor growth in some cancers. Previously, we developed mouse monoclonal antibodies against human CAR and found that one, mu6G10A, significantly inhibited tumor growth in xenografts of human cancer cells. Herein, we generated and characterized a mouse-human chimeric anti-CAR antibody (ch6G10A) from mu6G10A. ch6G10A had binding activity, inducing antibody-dependent cellular cytotoxicity and complement-dependent cytotoxicity, and in vivo anti-tumor activity against CAR-expressing prostate cancer DU-145 cells. In addition, cancer tissue array analysis confirmed that CAR is highly expressed in neuroendocrine lung cancers including small cell lung cancer, and treatment with ch6G10A effectively inhibited in vivo subcutaneous tumor growth of NCI-H69 small cell lung cancer cells in nude mice. Moreover, treatment with mu6G10A effectively inhibited both in vivo orthotopic tumor growth and distant metastatic formation in mouse xenograft models of a highly metastatic subline of human small cell lung cancer DMS273 cells. These results suggest that targeting therapy to CAR with a therapeutic antibody might be effective against several cancer types including small cell lung cancer.

Coxsackievirus Type B3 Is a Potent Oncolytic Virus against KRAS-Mutant Lung Adenocarcinoma

KRAS mutant (KRAS^mut) lung adenocarcinoma is a refractory cancer without available targeted therapy. The current study explored the possibility to develop coxsackievirus type B3 (CVB3) as an oncolytic agent for the treatment of KRAS^mut lung adenocarcinoma. In cultured cells, we discovered that CVB3 selectively infects and lyses KRAS^mut lung adenocarcinoma cells (A549, H2030, and H23), while sparing normal lung epithelial cells (primary, BEAS2B, HPL1D, and 1HAEo) and EGFR^mut lung adenocarcinoma cells (HCC4006, PC9, H3255, and H1975). Using stable cells expressing a single driver mutation of either KRAS^G12V or EGFR^L858R in normal lung epithelial cells (HPL1D), we further showed that CVB3 specifically kills HPL1D-KRAS^G12V cells with minimal harm to HPL1D-EGFR^L858R and control cells. Mechanistically, we demonstrated that aberrant activation of extracellular signal-regulated kinase 1/2 (ERK1/2) and compromised type I interferon immune response in KRAS^mut lung adenocarcinoma cells serve as key factors contributing to the sensitivity to CVB3-induced cytotoxicity. Lastly, we conducted in vivo xenograft studies using two immunocompromised mouse models. Our results revealed that intratumoral injection of CVB3 results in a marked tumor regression of KRAS^mut lung adenocarcinoma in both non-obese diabetic (NOD) severe combined immunodeficiency (SCID) gamma (NSG) and NOD-SCID xenograft models. Together, our findings suggest that CVB3 is an excellent candidate to be further developed as a targeted therapy for KRAS^mut lung adenocarcinoma.

Expression of coxsackie and adenovirus receptor is correlated with inferior prognosis in liver cancer patients

The coxsackie and adenovirus receptor (CAR), a tumor suppressor, is vital for the effectiveness of therapies which utilize the adenovirus. However, studies on CAR expression in hepatocellular carcinoma (HCC) are conflicting and its clinical significance requires exploration. In this study, immunohistochemistry has been carried out on tissue microarrays consisting of 198 pairs of HCC and neighboring healthy tissue specimens from Chinese Han patients to evaluate CAR expression. Relative to normal tissues, decreased CAR expression (56% vs. 57%; P>0.05) was detected in HCC samples. CAR immunopositivity in tumors was not dependent upon sex, age, tumor dimensions, differentiation, TNM stage or metastasis in HCC patients; however, positive expression was observed in 56% of the samples from patients with hepatic metastasis, which was the same as those devoid of metastasis (56%; P=0.042). Furthermore, survival analysis confirmed that the expression of CAR revealed no correlation with the prognosis. It was established that CAR exerted complex effects during liver tumorigenesis, potentially based on the stage of the cancer. Therefore, CAR expression analysis has to be carried out prior to adenoviral oncolytic therapy to stratify the patients.

Oncolytic virus immunotherapies in ovarian cancer: moving beyond adenoviruses

Ovarian cancer is the 5th most common cancer in UK women with a high relapse rate. The overall survival for ovarian cancer has remained low for decades prompting a real need for new therapies. Recurrent ovarian cancer remains confined in the peritoneal cavity in >80% of the patients, providing an opportunity for locoregional administration of novel therapeutics, including gene and viral therapy approaches. Immunotherapy is an expanding field, and includes oncolytic viruses as well as monoclonal antibodies, immune checkpoint inhibitors, and therapeutic vaccines. Oncolytic viruses cause direct cancer cell cytolysis and immunogenic cell death and subsequent release of tumor antigens that will prime for a potent tumor-specific immunity. This effect may be further enhanced when the viruses are engineered to express, or coadministered with, immunostimulatory molecules. Currently, the most commonly used and well-characterized vectors utilized for virotherapy purposes are adenoviruses. They have been shown to work synergistically with traditional chemotherapy and radiotherapy and have met with success in clinical trials. However, pre-existing immunity and poor in vivo models limit our ability to fully investigate the potential of oncolytic adenovirus as effective immunotherapies which in turn fosters the need to develop alternative viral vectors. In this review we cover recent advances in adenovirus-based oncolytic therapies targeting ovarian cancer and recent advances in mapping immune responses to oncolytic virus therapies in ovarian cancer.

Novel oncolytic viral therapies in patients with thoracic malignancies

Oncolytic virotherapy is the use of replication-competent viruses to treat malignancies. The potential of oncolytic virotherapy as an approach to cancer therapy is based on historical evidence that certain viral infections can cause spontaneous remission of both hematologic and solid tumor malignancies. Oncolytic virotherapy may eliminate cancer cells through either direct oncolysis of infected tumor cells or indirect immune-mediated oncolysis of uninfected tumor cells. Recent advances in oncolytic virotherapy include the development of a wide variety of genetically attenuated RNA viruses with precise cellular tropism and the identification of cell-surface receptors that facilitate viral transfer to the tissue of interest. Current research is also focused on targeting metastatic disease by sustaining the release of progeny viruses from infected tumor cells and understanding indirect tumor cell killing through immune-mediated mechanisms of virotherapy. The purpose of this review is to critically evaluate recent evidence on the clinical development of tissue-specific viruses capable of targeting tumor cells and eliciting secondary immune responses in lung cancers and mesothelioma.

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.

Two types of functionally distinct fiber containing structural protein complexes are produced during infection of adenovirus serotype 5

Adenoviruses are common pathogens. The localization of their receptors coxsackievirus and adenovirus receptor, and desmoglein-2 in cell-cell junction complexes between polarized epithelial cells represents a major challenge for adenovirus infection from the apical surface. Structural proteins including hexon, penton base and fiber are excessively produced in serotype 5 adenovirus (Ad5)-infected cells. We have characterized the composition of structural protein complexes released from Ad5 infected cells and their capacity in remodeling cell-cell junction complexes. Using T84 cells as a model for polarized epithelium, we have studied the effect of Ad5 structural protein complexes in remodeling cell-cell junctions in polarized epithelium. The initial Ad5 infection in T84 cell culture was inefficient. However, progressive distortion of cell-cell junction in association with fiber release was evident during progression of Ad5 infection. Incubation of T84 cell cultures with virion-free supernatant from Ad5 infected culture resulted in distortion of cell-cell junctions and decreased infectivity of Ad5-GFP vector. We used gel filtration chromatography to fractionate fiber containing virion–free supernatant from Ad5 infected culture supernatant. Fiber containing fractions were further characterized for their capacity to inhibit the infection of Ad5-GFP vector, their composition in adenovirus structural proteins using western blot and LC-MS/MS and their capacity in remolding cell-cell junctions. Fiber molecules in complexes containing penton base and hexon, or mainly hexon were identified. Only the fiber complexes with relatively high content of penton base, but not the fiber-hexon complexes with low penton base, were able to penetrate into T84 cells and cause distortion of cell-cell junctions. Our findings suggest that these two types of fiber complexes may play different roles in adenoviral infection.

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

Background:

The Coxsackie- and Adenovirus Receptor (CAR) has been assigned two crucial attributes in carcinomas: (a) involvement in the regulation of growth and dissemination and (b) binding for potentially therapeutic adenoviruses. However, data on CAR expression in cancer types are conflicting and several entities have not been analysed to date.

Methods:

The expression of CAR was assessed by immunohistochemical staining of tissue microarrays (TMA) containing 3714 specimens derived from 100 malignancies and from 273 normal control tissues.

Results:

The expression of CAR was detected in all normal organs, except in the brain. Expression levels, however, displayed a broad range from being barely detectable (for example, in the thymus) to high abundance expression (for example, in the liver and gastric mucosa). In malignancies, a high degree of variability was notable also, ranging from significantly elevated CAR expression (for example, in early stages of malignant transformation and several tumours of the female reproductive system) to decreased CAR expression (for example, in colon and prostate cancer types).

Conclusion:

Our results provide a comprehensive insight into CAR expression in neoplasms and indicate that CAR may offer a valuable target for adenovirus-based therapy in a subset of carcinomas. Furthermore, these data suggest that CAR may contribute to carcinogenesis in an entity-dependent manner.

Expression of the coxsackie and adenovirus receptor in human lung cancers

The aim of this study is to elucidate the relation between expression of coxsackie and adenovirus receptor (CAR) and formation of lung cancer. We investigated the expression of CAR by immunohistochemistry, Western blot and real-time RT-PCR in 120 lung cancers. We found that CAR expression in tumor tissues was significantly higher than that in normal lung tissues. CAR expression had a correlation with the histological grade of lung squamous cell carcinoma; however, there was no relationship between the CAR expression and the other clinical pathological features. In vitro, silencing or overexpression of CAR could significantly inhibit or promote colony formation, cell adhesion, and invasion in A549 cells. Our findings demonstrated that CAR may play an essential role in the formation of lung cancer.

Expression of the coxsackie adenovirus receptor in neuroendocrine lung cancers and its implications for oncolytic adenoviral infection

Coxsackie adenovirus receptor (CAR) is the primary receptor to which oncolytic adenoviruses have to bind for internalization and viral replication. A total of 171 neuroendocrine lung tumors in form of multitissue arrays have been analyzed resulting in a positivity of 112 cases (65.5%). Immunostaining correlated statistically significant with histopathology and development of recurrence. The subtype small cell lung cancer (SCLC) showed the highest CAR expression (77.6%), moreover the CAR level was correlated to the disease-free survival. Further, high CAR expression level in SCLC cell lines was found in vitro and in vivo when cell lines had been transplanted into immunodeficient mice. A correlation between CAR expression in the primary tumors and metastases development in the tumor model underlined the clinical relevance. Cell lines with high CAR level showed a high infectivity when infected with a replication-deficient adenovirus. Low levels of CAR expression in SCLC could be upregulated with Trichostatin A, a histone deacetylase inhibitor. As a result of the unaltered poor prognosis of SCLC and its high CAR expression it seems to be the perfect candidate for oncolytic therapy. With our clinically relevant tumor model, we show that xenograft experiments are warrant to test the efficiency of oncolytic adenoviral therapy.

Combination of vorinostat and adenovirus-TRAIL exhibits a synergistic antitumor effect by increasing transduction and transcription of TRAIL in lung cancer cells

Soluble TRAIL and adenovirus (ad)-TRAIL exhibit a strong antitumor effect by inducing apoptosis. Vorinostat is the histone deacetylase (HDAC) inhibitor that induces cell death in cancer cell lines and regulates the expression of epigenetically silenced genes, such as Coxackie adenoviral receptor (CAR), the receptor for adenoviral entry. We propose a new strategy in which vorinostat will induce high expression of ad-TRAIL and a strong antitumor response, and investigated the mechanism involved. The effect of vorinostat on transcription and expression of TRAIL from ad-TRAIL-transduced lung cancer cells were confirmed by reverse transciption-PCR (RT-PCR), quantitative real time-PCR and western blot assay. Anti-tumor effects were measured after cotreatment of vorinostat and ad-TRAIL, and the drug interactions were analyzed. After combined treatment of vorinostat and ad-TRAIL, apoptosis and western blot assays for Akt, Bcl-2 and caspase were performed. Vorinostat increased the expression of CAR in lung cancer cell lines and increased the expression of luciferase (luc) from ad-luc-transduced cells and TRAIL from ad-TRAIL-transduced cells. RT-PCR and quantitative real time-PCR, after sequential vorinostat treatment, revealed that vorinostat may enhance TRAIL expression from ad-TRAIL by increasing transduction through enhanced CAR expression and increasing adenoviral transgene transcription. Combined vorinostat and ad-TRAIL treatment showed the synergistic anti-tumor effect in lung cancer cell lines. Combined vorinostat and ad-TRAIL induced stronger apoptosis induction, suppression of NF-κB activation and breakdown of the anti-apoptotic molecule Bcl-2. In conclusion, the vorinostat synergistically enhanced the anti-tumor effect of ad-TRAIL by (1) increasing adenoviral transduction through the increased expression of CAR and (2) increasing adenoviral transgene (TRAIL) transcription in lung cancer cell lines.

Fiber mediated receptor masking in non-infected bystander cells restricts adenovirus cell killing effect but promotes adenovirus host co-existence

The basic concept of conditionally replicating adenoviruses (CRAD) as oncolytic agents is that progenies generated from each round of infection will disperse, infect and kill new cancer cells. However, CRAD has only inhibited, but not eradicated tumor growth in xenograft tumor therapy, and CRAD therapy has had only marginal clinical benefit to cancer patients. Here, we found that CRAD propagation and cancer cell survival co-existed for long periods of time when infection was initiated at low multiplicity of infection (MOI), and cancer cell killing was inefficient and slow compared to the assumed cell killing effect upon infection at high MOI. Excessive production of fiber molecules from initial CRAD infection of only 1 to 2% cancer cells and their release prior to the viral particle itself caused a tropism-specific receptor masking in both infected and non-infected bystander cells. Consequently, the non-infected bystander cells were inefficiently bound and infected by CRAD progenies. Further, fiber overproduction with concomitant restriction of adenovirus spread was observed in xenograft cancer therapy models. Besides the CAR-binding Ad4, Ad5, and Ad37, infection with CD46-binding Ad35 and Ad11 also caused receptor masking. Fiber overproduction and its resulting receptor masking thus play a key role in limiting CRAD functionality, but potentially promote adenovirus and host cell co-existence. These findings also give important clues for understanding mechanisms underlying the natural infection course of various adenoviruses.

CAR mediates efficient tumor engraftment of mesenchymal type lung cancer cells

The coxsackie-adenovirus receptor (CAR) is a developmentally regulated intercellular adhesion molecule that was previously observed to be required for efficient tumor formation. To confirm that observation, we compared the tumorigenicity of clonally derived test and control cell subsets that were genetically modified for CAR. Silencing CAR in lung cancer cells with high constitutive expression reduced engraftment efficiency. Conversely, overexpressing CAR in lung cancer cells with low constitutive expression did not affect tumor formation or growth kinetics. A blocking antibody to the extracellular domain of CAR inhibited tumor engraftment, implicating that domain as being important to this process. However, differences in adhesion properties attributable to this domain (barrier function and aggregation) could not be distinguished in the test groups in vitro, and the mechanisms underlying CAR's contribution to tumor engraftment remain elusive. Because high CAR cells displayed a spindle-shaped morphology at baseline, we considered whether this expression was an accompaniment of other mesenchymal features in these lung cancer cells. Molecular correlates of CAR were compared in model epithelial and mesenchymal type lung cancer cells. CAR expression is associated with an absence of E-cadherin, diminished expression of alpha- and gamma-catenin, and increased Zeb1, Snail, and vimentin expression in lung cancer cells. In contrast, epithelial type (NCI-H292, Calu3) lung cancer cells show comparatively low CAR expression. These data suggest that if the mesenchymal cell phenotype is an accurate measure of an undifferentiated and invasive state, then CAR expression may be more closely aligned with this phenotype of lung cancer cells.

Coxsackievirus and adenovirus receptor expression in human endometrial adenocarcinoma: possible clinical implications

The coxsackievirus and adenovirus receptor (CAR) is a crucial receptor for the entry of both coxsackie B viruses and adenoviruses into host cells. CAR expression on tumor cells was reported to be associated with their sensitivity to adenoviral infection, while it was considered as a surrogate marker for monitoring and/or predicting the outcome of adenovirus-mediated gene therapy. The aim of the present study was to evaluate the clinical significance of CAR expression in endometrial adenocarcinoma. CAR expression was assessed immunohistochemically in tumoral samples of 41 endometrial adenocarcinoma patients and was statistically analyzed in relation to various clinicopathological parameters, tumor proliferative capacity and patient survival. CAR positivity was noted in 23 out of 41 (56%) endometrial adenocarcinoma cases, while high CAR expression in 8 out of 23 (35%) positive ones. CAR intensity of immunostaining was classified as mild in 11 (48%), moderate in 10 (43%) and intense in 2 (9%) out of the 23 positive cases. CAR positivity was significantly associated with tumor histological grade (p = 0.036), as well differentiated tumors more frequently demonstrating no CAR expression. CAR staining intensity was significantly associated with tumor histological type (p = 0.016), as tumors possessing squamous elements presented more frequently intense CAR immunostaining. High CAR expression showed a trend to be correlated with increased tumor proliferative capacity (p = 0.057). Patients with tumors presenting moderate or intense CAR staining intensity were characterized by longer survival times than those with mild one; however, this difference did not reach statistical significance. These data reveal, for the first time, the expression of CAR in clinical material obtained from patients with endometrial adenocarcinoma in relation to important clinicopathological parameters for their management. As CAR appears to modulate the proliferation and characteristics of cancer cells, its expression could be considered of possible clinical importance for future (gene) therapy applications.