ABSTRACT
Nasopharyngeal carcinoma(NPC) is a metastatic carcinoma that is highly prevalent in Southeast Asia. Our laboratory has previously demonstrated that the C-terminal 27-kDa polypeptide of human telomerase reverse transcriptase (hTERTC27) inhibits the growth and tumorigenicity of human glioblastoma and melanoma cells. In this study, we investigated the antitumor effect of hTERTC27 in human C666-1 NPC cells xenografted in a nude mouse model. A cocktail of vectors comprising recombinant adeno-associated virus (rAAV) and recombinant adenovirus (rAdv) that each carry hTERTC27 (rAAV-hTERTC27 and rAdv-hTERTC27; the cocktail was abbreviated to rAAV/rAdv-hTERTC27) was more effective than either rAAV-hTERTC27 or rAdv-hTERTC27 alone in inhibiting the growth of C666-1 NPC xenografts. Furthermore, we established three tumors on each mouse and injected rAAV/rAdv-hTERTC27 into one tumor per mouse. Although hTERTC27 expression could only be detected in the injected tumors, reduced tumor growth was observed in the injected tumor as well as the uninjected tumors, demonstrating that the vector cocktail could provoke an antitumor effect on distant, metastasized tumors. Further studies showed the observed antitumor effects included inducing necrosis and apoptosis and reducing microvessel density. Together, our data suggest that the rAAV/rAdv-hTERTC27 cocktail can potently inhibit NPC tumor growth in both local and metastasized tumors and should be further developed as a novel gene therapy strategy for NPC.
Subject(s)
Animals , Humans , Male , Mice , Adenoviridae , Genetics , Apoptosis , Carcinoma , Cell Line, Tumor , Dependovirus , Genetics , Genetic Therapy , Methods , Genetic Vectors , Green Fluorescent Proteins , Metabolism , Mice, Inbred BALB C , Mice, Nude , Microvessels , Nasopharyngeal Neoplasms , Metabolism , Pathology , Neoplasm Transplantation , Recombinant Proteins , Genetics , Metabolism , Telomerase , Genetics , Metabolism , Tumor BurdenABSTRACT
BI-1 (Bax inhibitor-1), an apoptosis-inhibiting gene belonging to the Bcl-2 protein family, plays an important role in mitochondrial apoptosis pathway to suppress Bax-induced apoptosis. To investigate the potential role of BI-1 in promoting cell growth and tumorigenesis, in the present study we overexpressed the BI-1 gene in NIH3T3 cells using the lentivirus-mediated gene expression system. Our in vitro studies showed that NIH3T3 cells overexpressing BI-1 displayed a significantly higher growth rate and formed more and larger colonies than the control cells. In addition, our in vivo studies indicated that the lenti-BI-1-infected cells formed obvious tumours, while no tumours were formed by the control cells after subcutaneously injected into nude mice. These results strongly suggested that the BI-1 gene might play a crucial role in neoplastic genesis and development.
Subject(s)
Apoptosis Regulatory Proteins/metabolism , Cell Transformation, Neoplastic , Membrane Proteins/metabolism , Animals , Apoptosis , Apoptosis Regulatory Proteins/genetics , Cell Transformation, Neoplastic/genetics , Cells, Cultured , Gene Expression Regulation , Humans , Membrane Proteins/genetics , Mice , Mice, Nude , NIH 3T3 Cells , TransfectionABSTRACT
BMP-4 signaling is mediated through Smad proteins which may translocate to the nucleus to activate transcription. Little is known about how BMP-4 signaling regulates the transcription of its target genes, e.g., Xvent genes. Therefore, we isolated the genomic clone of a BMP-4 responsive homeobox gene, Xbr-1a/Xvent-2. This clone contains a promoter and three exons for the entire coding region. Using the primer extension, we identified the transcription initiation site corresponding to position -64 bp upstream to the ATG codon of the Xvent-2 gene. The promoter was linked to the luciferase reporter gene, and promoter activity determined by luciferase assay. The temporal promoter activity peaked between embryonic stages 13~17, in agreement with its temporal mRNA expression in the whole embryo. Through the serial deletion mutation, the upstream -235 bp of the promoter retains the full transcriptional activity, and is regulated by BMP-4 signaling. The present results suggest that the BMP-4 responsive element is located on the upstream 235 bp of the promoter.
