Ectopic expression of the coxsackievirus and adenovirus receptor increases susceptibility to adenoviral infection in the human cervical cancer cell line, SiHa

The roles of cell surface attachment molecules and coagulation Factor X in adenovirus 5-mediated gene transfer in pancreatic cancer cells

Transduction of 11 pancreatic cancer cell lines with a replication-deficient adenovirus 5 expressing enhanced green fluorescent protein (Ad5EGFP) was analyzed and variable EGFP levels were observed, ranging from <1% to ∼40% of cells transduced, depending on the cell line. Efficient Ad5EGFP transduction was associated mainly with higher levels of cell surface Coxsackie and adenovirus receptor (CAR) but not with expression of α(v)β(3) and α(v)β(5) integrins and was fiber dependent. Reduction of CAR by RNA interference resulted in a corresponding decrease in Ad5EGFP transduction. Pre-treatment of Ad5EGFP with blood coagulation Factor X increased virus entry even in the presence of low CAR levels generated by RNA interference, suggesting a potential alternative route of Ad5 entry into pancreatic cancer cells. Immunohistochemistry carried out on 188 pancreatic ductal adenocarcinomas and 68 matched controls showed that CAR was absent in 102 (54%) of adenocarcinomas, whereas moderate and strong staining was observed in 58 (31%) and 28 (15%) cases, respectively. Weak or absent CAR immunolabeling correlated with poor histological differentiation of pancreatic cancer. In normal tissue, strong immunolabeling was detected in islet cells and in the majority of inter- and intralobular pancreatic ducts.

The prevalence of antibodies to adenovirus serotype 5 in an adult Indian population and implications for adenovirus vector vaccines

In vivo gene delivery using human adenovirus serotype 5 (AdV5) vectors is being explored for vaccination purposes. The presence of anti-AdV5 antibodies in human serum arising from natural exposure to AdV5 can interfere potentially with and compromise the efficacy of rAdV5-based vaccine vectors. In this report, a collection of 114 sera from healthy adult Indian blood donors was analyzed for the presence of anti-AdV5 antibodies, using an AdV5 vector encoding the green fluorescent protein (GFP) to monitor the presence of anti-AdV5 neutralizing antibodies in human sera based on their ability to block virus entry into HeLa cells which express the Coxsackievirus-and-Adenovirus Receptor (CAR). In this assay all samples tested were positive for anti-AdV5 antibodies, with titers varying over a very wide range. It was also observed that these antibodies facilitated the uptake of the reporter AdV5 vector into the monocytic cell line U937 which does not express CAR, but expresses Fc receptors (FcRs) instead. These observations have implications for rAdV5-based vaccine development. J. Med. Virol. 82:407-414, 2010. (c) 2010 Wiley-Liss, Inc.

Role of genetic susceptibility to latent adenoviral infection and decreased lung function

BACKGROUND

Latent adenoviral infection may amplify cigarette smoke-induced lung inflammation and therefore play an important role in the development of chronic obstructive pulmonary disease (COPD). Adenoviruses can evade the human immune response via their 19-kDa protein (19K) which delays the expression of class I human leukocyte antigen (HLA) proteins. The 19K protein shows higher affinity to HLA-B7 and A2 compared with HLA-A1 and A3. The receptor for adenovirus (CXADR) and integrin beta(5) (ITGB5) are host factors which might affect adenovirus infection. Therefore, we investigated the contribution of HLA, CXADR, and ITGB5 genetic variants to the presence of the E1A gene and to level of lung function.

METHODS

Study subjects were assayed for HLA-B7, A1, A2 and A3 by PCR-based assays using allele-specific primers. Polymorphisms of the CXADR and ITGB5 genes were genotyped by PCR-based restriction fragment length polymorphism assays. Detection of adenoviral E1A gene was performed by a real-time PCR TaqMan assay.

RESULTS

E1A positive individuals had a lower FEV(1) compared with E1A negative individuals. However, there was no significant difference in E1A positivity rate between the high (HLA-B7 and A2) and low (HLA-A1 and A3) 19K affinity groups. There was also no significant difference in FEV(1) level between each affinity group. There was no significant difference in E1A positivity rate or lung function among the CXADR and ITGB5 genotypes.

CONCLUSIONS

Genetic variants in HLA, CXADR and ITGB5 do not influence latent adenoviral infections and are not associated with COPD.

Analysis of the expression of coxsackievirus and adenovirus receptor in five colon cancer cell lines

AIM: To investigate the expression of coxsackievirus and adenovirus receptor (CAR) and adenovirus-mediated reporter gene transfer in five human colon cancer cell lines.

METHODS: Expression of CAR-specific mRNA and protein was analyzed by reverse transcriptase polymerase chain reaction and Western blotting, respectively. Adenovirus-based gene delivery was evaluated by infection of cells with adenoviral vector carrying the green fluorescent protein (GFP) gene.

RESULTS: All the colon cancer cell lines examined (HT29, LS180, SW480, SW948 and SW1116) expressed CAR full-length mRNA and an alternatively-spliced variant that lacks the transmembrane coding exon. All cell lines were detected as CAR-positive by Western blot analysis. Further, all cells we examined were efficiently infected with adenoviral vector-GFP.

CONCLUSION: The data indicated that the five colon cancer cell lines tested expressed adenovirus primary receptor and could be efficiently infected by adenoviral vectors. Therefore, these cell lines will be useful for adenovirus-based gene transfer and research.

Modification of liposomal concentration in liposome/adenoviral complexes allows significant protection of adenoviral vectors from neutralising antibody, in vitro

Adenoviral vectors have been commonly used in gene therapy protocols, however the success of their use is often limited by the induction of host immunity to the vector. Following exposure to the adenoviral vector, adenoviral-specific neutralising antibodies are produced which limits further administration. This study examines the efficacy of complexing liposomes to adenovirus for the protection of the adenovirus from neutralising antibodies in an in vitro setting. Dimethyldioctadecylammonium bromide (DDAB)-dioleoyl-l-phosphatidylethanolamine (DOPE) liposomes were bound at varying concentrations to adenovirus to form AL complexes and tested these complexes' ability to prevent adenoviral neutralisation. It is shown that by increasing the concentration of liposomes in the adenoviral-liposome (AL) complexes we can increase the level of immuno-shielding afforded the adenovirus. It is also shown that the increase in liposomal concentration may lead to drawbacks such as increased cytotoxicity and reductions in expression levels.

Microsphere-liposome complexes protect adenoviral vectors from neutralising antibody without losses in transfection efficiency, in-vitro

Adenoviral vectors have been commonly used in gene therapy protocols but the success of their use is often limited by the induction of host immunity to the vector. Following exposure to the adenoviral vector, adenoviral-specific neutralising antibodies are produced, which limits further administration. This study examines the effectiveness of a novel combination of microspheres and liposomes for the shielding of adenovirus from neutralising antibodies in an in-vitro setting. We show that liposomes are effective in the protection of adenovirus from neutralising antibody and that the conjugation of these complexes to microspheres augments the level of protection. This study further reveals that previously neutralised adenovirus may still be transported into the cell via liposome-cell interactions and is still capable of expressing its genes, making this vector an effective tool for circumvention of the humoral immune response. We also looked at possible side effects of using the complexes, namely increases in cytotoxicity and reductions in transfection efficiency. Our results showed that varying the liposome:adenovirus ratio can reduce the cytotoxicity of the vector as well as increase the transfection efficiency. In addition, in cell lines that are adenoviral competent, transfection efficiencies on par with uncomplexed adenoviral vectors were achievable with the combination vector.

Identification of genes up-regulated by histone deacetylase inhibition with cDNA microarray and exploration of epigenetic alterations on hepatoma cells

BACKGROUND/AIMS

Epigenetics is the key factor in the regulation of gene expression. We conducted cDNA microarray analysis to screen for genes induced by histone deacetylase (HDAC) inhibition and examined epigenetic alterations.

METHODS

Microarray analysis was performed in six hepatoma cell lines and primary hepatocytes treated with trichostatin A (TSA). mRNA expression of several genes was examined by reverse transcription-polymerase chain reaction in TSA-treated cells and hepatoma samples. Acetylated histones and methylation status in 5'CpG islands was assessed by chromatin immunoprecipitation (ChIP) assay and bisulfite genomic sequencing, respectively.

RESULTS

Fifty-seven genes showed greater than 2-fold change after TSA treatment in multiple cell lines. Among them, four genes including p21(WAF1) exhibited substantial induction (greater than 5-fold changes). Decreased mRNA levels of these genes in hepatoma tissues were observed in more than half of patients. ChIP assay, in general, demonstrated a good correlation between mRNA expression and histone acetylation, but only a limited correlation with the methylated DNA in the promoter region.

CONCLUSIONS

We identified 57 up-regulated genes by TSA treatment in hepatoma cells and some of them appeared to be cancer-related genes in hepatomas. The alterations in acetylated histones are likely closely associated with gene expression.

Gene transfer to cervical cancer with fiber-modified adenoviruses

Successful adenoviral (Ad) vector-mediated strategies for cancer gene therapy mandate gene-delivery systems that are capable of achieving efficient gene delivery in vivo. In many cancer types, in vivo gene-transfer efficiency remains limited due to the low or highly variable expression of the primary Ad receptor, the coxsackie Ad receptor (CAR). In this study, we evaluated the expression of CAR on cervical cancer cells as well as CAR-independent targeting strategies to integrins (Ad5.RGD), heparan sulfate proteoglycans (Ad5.pK7) or both (Ad5.RGD.pK7). We used a panel of established cervical cancer cell lines and primary cervical cancer cells isolated from patients to quantify the expression of CAR mRNA and to evaluate the gene-transfer efficiency of fiber-modified Ads. Of the fiber-modified vectors, Ad5.pK7 and Ad5.RGD.pK7 displayed significantly enhanced gene-transfer efficiency in vitro. Gene-delivery efficiency in vivo was evaluated using an s.c. cervical cancer mouse model. Ad5.RGD.pK7 significantly improves tumor targeting in vivo, resulting in a significantly improved tumor/liver ratio in mice. Our results suggest that the double-modified Ad5.RGD.pk7 vector enhances gene transfer to clinically relevant cervical cancer substrates, while the infectivity of nontarget cells in the mouse is not increased and comparable to Ad5. The fiber-modified virus described here can help achieve higher clinical efficacy of cervical cancer gene therapy.

In-vitro evaluation of ion-exchange microspheres for the sustained release of liposomal–adenoviral conjugates

This study looks at the development of a novel combination vector consisting of adenovirus conjugated to liposomes (AL complexes) bound to cation-exchanging microspheres (MAL complexes). With adenovirus having a net negative charge and the liposomes a net positive charge it was possible to modify the net charge of the AL complexes by varying the concentrations of adenovirus to liposomes. The modification of the net charge resulted in altered binding and release characteristics. Of the complexes tested, the 5:1 and 2:1 ratio AL complexes were able to be efficiently bound by the microspheres and exhibited sustained release over 24 h. The 1:1 and 1:2 AL complexes, however, bound poorly to the microspheres and were rapidly released. In addition the MAL complexes also were able to reduce the toxicity of the AL complexes, which was seen with the 10:1 ratio. The AL complexes showed considerably more toxicity alone than in combination with microspheres, highlighting a potential benefit of this vector.

Recombinant adenovirus-p53 gene transfer and cell-specific growth suppression of human cervical cancer cells in vitro and in vivo

PURPOSE

We investigated the time-course expression patterns of p53 and E6 on cervical cancer cells to obtain a molecular level understanding of cell-dependent tumor growth suppression effects of recombinant adenovirus expressing p53 in vitro and in vivo.

METHODS

Four human papillomavirus (HPV)-infected human cervical cancer cell lines (HPV 16-positive cells, CaSki and SiHa cells; and HPV 18-positive cells, HeLa and HeLaS3 cells) were used. Also, HPV negative C33A and HT3 cell line that has a mutation on p53 gene were used. After infection with AdCMVp53, the cell growth inhibition was studied via cell count assay, MTT assay, and Neutral red assay. After transfecting AdCMVp53 and AdCMVLacZ into the cancer cells-xenografted nude mice, antitumor effects were investigated for 1 month, respectively.

RESULTS

For each cervical cancer cell, IC50 was as follows; CaSki (68.5 multiplicity of infection, or MOI), SiHa (43.5 MOI), HeLa (31 MOI), HeLaS3 (42 MOI), C33A (21 MOI), and HT3 (62 MOI). In particular, complete inhibition of cell growth was observed at 125 MOI in both CaSki and SiHa cells. However, the complete inhibition was detected at 62.5 MOI in HeLa and HeLaS3. In contrast, at these MOI, no suppression of cell growth was observed when cells were infected with recombinant adenovirus expressing beta-gal as a negative control. The levels of p53 protein were notably expressed in CaSki and HeLa more than in SiHa and HeLaS3 on days 2 and 4. However, the p53 was only detected in HeLaS3 on day 6. In contrast, p53 expression was continually maintained in C33A and HT3 during the same periods. After transfection AdCMVp53 into CaSki- and SiHa-xenografted nude mice, the size of tumor was remarkably decreased in SiHa cells as compared to AdCMVLacZ transfection.

CONCLUSION

The adenovirus-mediated p53 gene transfection was done effectively in vitro and in vivo. Also, the antitumor effects were accomplished via differential role of p53-specific apoptotic cell death, which is dependent upon the cervical cancer cell line.

Transcriptional profiling of IKK2/NF-kappa B- and p38 MAP kinase-dependent gene expression in TNF-alpha-stimulated primary human endothelial cells

Inflammatory stimulation of endothelial cells by tumor necrosis factor alpha (TNF-alpha) involves activation of nuclear factor kappa B (NF-kappa B) and p38 mitogen-activated protein (MAP) kinase signaling pathways. A reliable analysis of the gene expression program elicited by TNF-alpha and its assignment to distinct signaling pathways is not available. A sophisticated analysis of oligonucleotide microarrays covering more than 13 000 genes allowed definition of the TNF-alpha-regulated endothelial gene expression profile and novel TNF-alpha-induced genes. Virtually all TNF-alpha-inducible genes were dependent on I kappa B kinase 2 (IKK2)/NF-kappa B activation, whereas a minor number was additionally modulated by p38. Furthermore, genes suppressed by IKK2/NF-kappa B were newly identified. Real-time reverse transcriptase-polymerase chain reaction (RT-PCR) and flow cytometry confirmed reliability of data. Thus, these results define a list of primary candidates for targeted modulation of endothelial functions during inflammation.

Enhancement of the adenoviral sensitivity of human ovarian cancer cells by transient expression of coxsackievirus and adenovirus receptor (CAR)

OBJECTIVE

The coxsackievirus and adenovirus receptor (CAR) is known to be a primary receptor for attachment during adenovirus infection of target cells and thus is closely related to adenoviral infection efficiency. To extend this notion to human ovarian cancer, we investigated the difference in expression levels of CAR in human ovarian cancer cell lines and whether their adenoviral sensitivities are enhanced by transient transfection of the CAR gene.

METHODS

Adenoviral infection efficiency was examined by flow cytometry analysis, beta-galactosidase staining, and beta-galactosidase activity assay. Expression of the CAR-specific mRNA and protein was analyzed by reverse transcription polymerase chain reaction and flow cytometry, respectively.

RESULTS

Expression of CAR in human ovarian cancer cell lines (SKOV3, 2774, PA-1, and OVCAR3) appeared to be correlated with their susceptibilities to adenovirus-mediated gene delivery. The 2774 and PA-1 cells expressing an easily detectable level of CAR on the cell surface showed a higher susceptibility to infection with both AdCMVGFP and AdRSVbetagal than SKOV3 and OVCAR3 cells, both of which had hardly detectable levels of CAR. Ectopic expression of the CAR gene by transient transfection of these ovarian cancer cells resulted in a dramatic increase in their adenoviral sensitivities.

CONCLUSION

These data show that the expression of CAR is closely related to susceptibility to adenovirus infection in human ovarian cancer cells. These results indicate that the CAR gene can be a useful tool in boosting the efficiency of adenoviral vector-mediated gene therapy against human ovarian cancer.