RESUMO
Although JC virus (JCV), a human polyomavirus, has been detected in colon cancers, the association between JCV and colon cancer remains controversial. In Taiwan, the prevalence of JCV infection in colon cancer patients has not been reported. Thus, the purpose of this study was to investigate JCV infection in colon cancers in Taiwan. Formalin-fixed, paraffin-embedded tissues from 22 colon cancer patients were examined in this study. Nested PCR was performed to detect viral genomic DNA. The product of the nested PCR flanking the JCV regulatory region was sequenced further. Viral large tumor protein, LT, and late capsid protein, VP1, were examined by immunohistochemistry (IHC). Nested PCR revealed JCV genomic DNA in 86.4% (19/22) of the colon cancer tissue samples. Both rearranged and archetypal genotypes of JCV were identified. Expression of JCV LT was positive in 63.6% (14/22) of the examined colon cancer tissue samples but not in any adjacent normal region. Expression of viral capsid protein VP1 was not detected in any of the tissues examined. The current study demonstrates that JCV genomic DNA was present in the examined colon cancer tissues. The genotypes of JCV in colon cancer tissues were also identified. Expression of viral early protein but not structural capsid protein was detected in the examined colon cancer tissues. Furthermore, a high prevalence of JCV infection in colon cancer tissues in Taiwan was also demonstrated.
Assuntos
Adenocarcinoma/virologia , Neoplasias do Colo/virologia , Vírus JC/genética , Infecções por Polyomavirus/epidemiologia , Infecções por Polyomavirus/virologia , Infecções Tumorais por Vírus/epidemiologia , Infecções Tumorais por Vírus/virologia , Idoso , Proteínas do Capsídeo/análise , Proteínas do Capsídeo/biossíntese , Colo/virologia , DNA Viral/análise , Feminino , Humanos , Imuno-Histoquímica , Vírus JC/classificação , Vírus JC/isolamento & purificação , Vírus JC/metabolismo , Masculino , Pessoa de Meia-Idade , Reação em Cadeia da Polimerase , Infecções por Polyomavirus/complicações , Prevalência , Estudos Retrospectivos , Análise de Sequência de DNA , Taiwan/epidemiologia , Infecções Tumorais por Vírus/complicaçõesRESUMO
Human JC virus (JCV) is a neurotropic virus, and the etiological agent of progressive multifocal leukoencephalopathy (PML), a fatal neurological disease. Because of its natural infection tropism, it is possible to use the JCV capsid as a gene-transducing vector for therapeutic purposes in neurological disorders. In the current study, a recombinant JCV virus-like particle (VLP) was generated and purified from yeast. VLP was able to accommodate and protect DNA molecules of up to approximately 2000 bp in length. VLP was able to package and deliver an antisense oligodeoxynucleotide (AS-ODN) against simian virus 40 (SV40) large tumor antigen (LT) into SV40-transformed human fetal glial (SVG) cells in order to inhibit expression of the oncoprotein. Subsequently, apoptosis of VLP-AS-ODN-treated cells was demonstrated after the blocking of LT expression. In addition, JCV VLP was able to deliver ODN into human astrocytoma, neuroblastoma, and glioblastoma cells with high efficiency. In vivo delivery of ODN into a human neuroblastoma tumor nodule by VLP was also demonstrated. These findings suggest that JCV VLP is a gene delivery vector with potential therapeutic use for human neurological disorders.
Assuntos
Antígenos Transformantes de Poliomavirus/metabolismo , Vetores Genéticos , Vírus JC/genética , Leucoencefalopatia Multifocal Progressiva/terapia , Neuroglia/citologia , Neuroglia/metabolismo , Oligonucleotídeos Antissenso/genética , Oligonucleotídeos Antissenso/farmacologia , Anexina A5/farmacologia , Apoptose , Western Blotting , Encéfalo/metabolismo , Linhagem Celular Tumoral , Células Cultivadas , DNA/metabolismo , Técnicas de Transferência de Genes , Terapia Genética/métodos , Humanos , Concentração de Íons de Hidrogênio , Microscopia de Contraste de Fase , Doenças do Sistema Nervoso/terapia , Oligonucleotídeos/química , Oligonucleotídeos/genética , Regiões Promotoras Genéticas , Propídio/farmacologia , Fatores de Tempo , Transfecção , Raios UltravioletaRESUMO
To investigate the DNA binding activity of the JC virus minor capsid protein, VP2, both wild-type and mutant VP2 were cloned and expressed in Escherichia coli. Southwestern blotting was employed for the DNA-binding assay. The results showed that VP2 was able to bind to DNA, except when either the last 13 or the last 29 amino acids were truncated. The results indicate that the DNA-binding domain of VP2 is located within the last 13 amino acids. Furthermore, we also demonstrated that Lys(332) and Lys(336) within the DNA-binding domain are crucial for DNA binding. The findings may provide further information for understanding the mechanism of virion assembly of the JC virus.
