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J Trojan

Publications and source records attributed to J Trojan.

94 records · Page 6Linked to original sources
PubMedDate not supplied

IGF-I triple helix strategy in hepatoma treatment.

BACKGROUND/AIMS: To investigate the effect of gene therapy for hepatocellular carcinoma based on inhibition of cellular IGF-I expression, the technique of IGF-I triple helix was investigated in mice developing programmed hepatoma. METHODOLOGY: mhAT1F1 mouse hepatoma cell line was transfected in vitro with IGF-I triple helix expression vector (pMT-AG-TH) or with IGF-I antisense expression vector (pMT-Anti-IGF-I). 10 x 10(6) transfected cells of either triple helix or antisense type were inoculated intraperitonealy into transgenic ATIIITB6 mice developing genetically programmed hepatoma (mice die between the age of 6 and 7 months). In parallel, human cell cultures established from surgically removed hepatomas were investigated. RESULTS: mhAT1F1 and human primary cell cultures, transfected with pMT-AG-TH or pMT-Anti-IGF-I vectors resulted in total inhibition of IGF-I demonstrated by immunocytochemical and Northern blot techniques. Transfected cells changed their phenotype and recovered major histocompatibility complex I expression showed by fluorescence-activated cell sorting analysis and Western blot. Moreover, two phenomena were observed in IGF-I "antisense" or "triple helix" transfected cells: 1) the apoptosis, demonstrated by TUNEL technique; 2) the presence of IL-6 simultaneously with disappearance of tumor necrosis factor-alpha and IL-10, investigated by reverse transcriptase-polymerase chain reaction technique. In in vivo experiments, injection of murine transfected cells into mice in terminal-phase prolonged their survival 3-4 months in 100% of cases, as well in "antisense" group (8/8) as in "triple helix" group (10/10). CONCLUSIONS: Injection of hepatoma cells transfected with IGF-I triple helix expression vector, and showing immunogenic and apoptotic characteristics, can constitute an effective cellular therapy against hepatocellular carcinoma.

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PubMedDate not supplied

Potential triple helix-mediated inhibition of IGF-I gene expression significantly reduces tumorigenicity of glioblastoma in an animal model.

Oligonucleotide-directed triple helix formation is a powerful approach to block transcription of specific genes. Although the oligonucleotide triplex approach is efficient for inhibiting gene expression in cultured cells, suppression is transient. We developed an approach which inhibits insulin-like growth factor-I (IGF-I) expression following stable transfection of C6 rat glioblastoma cells with a plasmid from which an RNA is transcribed that codes for the third strand of a potential triple helix. We tested the ability of this expression vector to inhibit IGF-I gene expression in vitro as well as tumorigenesis in an animal. A dramatic reduction of IGF-I RNA and protein levels in cultured cells occurred following transfection of rat C6 cells with a eukaryotic expression plasmid encoding the oligopurine variant of the triple helix but not the oligopyrimidine or a control sequence. The cells transfected with the oligopurine variant displayed morphological changes, upregulation of major histocompatibility complex I, and increased expression of protease nexin I. Dramatic inhibition of tumor growth occurred in nude mice following injection of transfected C6 cells. To our knowledge, this is the first example of tumor growth inhibition in an animal model employing a triple helix approach.

Amyloid beta-Protein Precursor↗
PubMedDate not supplied

Antisense insulin-like growth factor I transferred into a rat hepatoma cell line inhibits tumorigenesis by modulating major histocompatibility complex I cell surface expression.

We have established a hepatocarcinoma cell line (LFCI2 A) that produces voluminous tumors when injected subcutaneously into syngeneic Commentry rats. These neoplastic cells express both insulin-like growth factors (IGF) I and II. When transfected with an episomal cassette-expressing IGF-I antisense RNA, the modified LFCI2 A cell lines become poorly tumorigenic and, when injected subcutaneously, are associated with inhibition of the growth of the parental tumoral cells and/or induction of regression of established tumors. By contrast, cell lines isolated after transfection with the IGF-II antisense-expressing vector were as tumorigenic as the parental cell lines. The results are discussed in terms of protective immunity induced by the tumoral cells transfected by the IGF-I antisense vector. In the transfected hepatocarcinoma cells that do not produce IGF-I, the expression of major histocompatibility complex class I antigen was increased at least 4-fold compared with parental cells. The introduction of these cells in vivo induced a tumor-specific immunity that was associated with CD8 T cells.

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