Antisense anti IGF-I cellular therapy of malignant tumours: immune response in cancer patients.

The treatment of cancer by antisense anti-IGF-I cellular therapy inducing immune response has evoked interest among many promising strategies. Here, we reported some results obtained from patients with cancer, mainly glioblastoma treated by this strategy, which was also extended to patients with colon carcinoma, ovary cystadenocarcinoma and prostate adenocarcinoma. It was shown that, in the phase I of clinical trial, patients vaccinated with their own tumour cells treated by antisense IGF-I presented a slight increase of temperature. Their peripheral blood lymphocytes showed a shift in the percentage of CD8 effector cells as judged by expression of cell surface markers CD8+ CD28+. Particularly, in two treated patients with glioblastoma, the survival time was 19 and 24 months respectively in comparison to the range of 12 to 15 months observed in the case of classical treatment such as surgery, radiation or chemotherapy. These results, although preliminary, gave indication that the reported strategy could deserve consideration owing to its safety. Furthermore, the increase in the percentage of peripheral blood monomorphonucleated cells (PBMNCs) with effector phenotype, i.e., CD8+ CD28+ in vaccinated patients might explain their prolonged survival time.

Presence of MHC-I in rat glioma cells expressing antisense IGF-I-receptor RNA.

The supposed immunogenic character of glioma cells transfected with antisense IGF-I-Receptor (IGF-I-R) expression vector was tested for the presence of MHC-I currently present in cells of IGF-I antisense type. C6 rat glioma cell line was comparatively transfected in vitro with IGF I antisense (pMT-Anti-IGF I) or IGF I Receptor antisense (pMT-Anti-IGF I R) expression vectors. The wild and transfected cells were examined for the presence of IGF-I and MHC-I molecules. Using RT PCR technique, the transfected "antisens" cells showed total inhibition of IGF-I. The both transfected cultures of IGF-I and of IGF-I-R type were positively stained for MHC-I. Moreover "antisense IGF-I-R" cells as compared to "IGF-I antisense" cells showed slightly higher expression of MHC-I. The transfected cells showed also the feature of apoptosis in 60% of cells. The immunogenicity of IGF-I-R antisense glioma cells is related to MHC-I presence; therefore both approaches of antisense IGF-I and of antisense IGF-I-R could be use in paralel for cellular therapy of glioblastoma.

IGF-I triple helix gene therapy of rat and human gliomas.

PURPOSE: IGF-I anti-gene technology was applied in treatment of rat and human gliomas using IGF-I triple helix approach. MATERIAL AND METHODS: CNS-1 rat glioma cell and primary human glioblastoma cell lines established from surgically removed glioblastomas multiforme were transfected in vitro with IGF-I antisense (pMT-Anti-IGF-I) or IGF-I triple helix (pMT-AG-TH) expression vectors. The transfected cells were examined for immunogenicity (immunocytochemistry and flow cytometry analysis) and apoptosis phenomena (electron microscopy). 3 x 10(6) transfected cells were inoculated subcutaneously either into transgenic Lewis rats or in patients with glioblastoma. The peripheral blood lymphocytes (PBL) derived from "vaccinated" patients were immunophenotyped for the set of CD antigens (CD4, CD8 etc). RESULTS: Using immunocytochemistry and Northern blot techniques, the transfected "antisense" and "triple-helix" cells showed total inhibition of IGF. Transfected cultures were positively stained either for both MHC-I and B7 antigens--60% of cloned lines, or for MHC-I only--40% of cloned lines. Moreover "triple helix" cells as compared to "antisense" cells showed slightly higher expression of MHC-I or B7. Transfected cells also showed the feature of apoptosis in 60%-70% of cells. In in vivo experiments with rats bearing tumors, the injection of "triple helix" cells expressing both MHC-I and B7 interrupted tumor growth in 80% of cases. In contrast, transfected cells expressing only MHC-I stopped development in 30% of tumors. In five patients with surgically resected glioblastoma who were inoculated with "triple helix" cells, PBL showed an increased percentage of CD4 + CD25+ and CD8 + CD11b-cells, following two vaccinations. CONCLUSIONS: The anti-tumor effectiveness of IGF-I anti-gene technology may be related to both MHC-I and B7 expression in cells used for therapy. The IGF-I antigene therapy of human glioblastoma multiforme increases immune response of treated patients.

Human glioma cells transformed by IGF-I triple helix technology show immune and apoptotic characteristics determining cell selection for gene therapy of glioblastoma.

AIMS: Insulin-like growth factor type I (IGF-I) antisense cellular gene therapy of tumours is based on the following data: rat glioma or hepatoma cells transfected with the vector encoding IGF-I antisense cDNA lose their tumorigenicity and induce a tumour specific immune response involving CD8(+) T cells. Recently, using the IGF-I triple helix approach in studies of tumorigenicity, major histocompatibility complex class I (MHC-I) antigens were demonstrated in rat glioma transfected cells. This study used comparative IGF-I antisense and triple helix technologies in human primary glioma cells to determine the triple helix strategy that would be most appropriate for the treatment of glioblastoma. METHODS: The cells were transfected using the IGF-I triple helix expression vector, pMT-AG, derived from the pMT-EP vector. pMT-AG contains a cassette comprising a 23 bp DNA fragment transcribing a third RNA strand, which forms a triple helix structure within a target region of the human IGF-I gene. Using pMT-EP, vectors encoding MHC-I or B7 antisense cDNA were also constructed. RESULTS: IGF-I triple helix transfected glioma cells are characterised by immune and apoptotic phenomena that appear to be related. The expression of MHC-I and B7 in transfected cells (analysed by flow cytometry) was accompanied by programmed cell death (detected by dUTP fluorescein terminal transferase labelling of nicked DNA and electron microscopic techniques). Cotransfection of these cells with MHC-I and B7 antisense vectors suppressed the expression of MHC-I and B7, and was associated with a pronounced decrease in apoptosis. CONCLUSION: When designing an IGF-I triple helix strategy for the treatment of human glioblastoma, the transfected tumour cells should have the following characteristics: the absence of IGF-I, the presence of both MHC-I and B7 molecules, and signs of apoptosis.