Escape from immune recognition has been hypothesized to be a factor in carcinogenesis. It may be mediated for many cancers through down-regulation in the MHC class 1 antigen processing and presentation pathway. TAP-1, TAP-2, tightly linked to LMP-2 and LMP-7 are multiple components of the endogenous, antigen presentation pathway machinery. We addressed the question of alterations in this pathway in human Glioblastoma (HGB) and of its relationship to modulation in expression of IGF-1 that is highly expressed in this cancer. Deficiencies in expression of TAP-1 were demonstrated by RT-PCR and/or by immuno-flow cytometry in the HGB cell line T98G obtained from ATCC, and in 3 of 4 human cell lines established from patients with Glioblastoma Multiforme. Deficiencies in expression of TAP-2 were observed in 3 of 4, deficiencies in expression of LMP-2 in 4 of 4 and deficiencies in LMP-7 in 3 of 4 HGB cell lines examined by RT-PCR and Western blot. Following down-regulation of IGF-1 by transfection with the pAnti IGF-1 vector that expresses IGF-1 RNA in antisense orientation, or by the exogenous addition of IGF-1 receptor monoclonal antibody to cell culture media, the deficiencies in components of the MHC-1 antigen presentation pathway were up-regulated and/or rescued in all HGB cell lines tested. Moreover, this up-regulation in expression was aborted by addition of 100 ng/ml of IGF-1 to the culture media. Unlike in the case of IFN-γ, the restoration of TAP-1 and LMP-2 by down-regulation of IGF-1 in Glioblastoma cells was not correlated to the tyrosine phosphorylation of STAT 1. In summary, the simultaneous reversion in expression of the multiple constituents of MHC-1 antigen processing path and up-regulation in expression of MHC-1 occurring with down-regulation in IGF-1 may have a role in reinforcement of immunity against tumor antigen(s) in some animal cancers and in humans with Glioblastoma Multiforme.

IGF-I, insulin-like growth factor 1, is present in normal fetal/neonatal brain development and reappears in the mature brain participating in the development of malignant tumor, glioblastoma multiforme. Targeting the IGF-I system has emerged as a useful method to reduce glial malignant development. Downregulation in the expression of IGF-I using antigene anti-IGF-I technology (antisense, AS, and triple helix, TH) applied in glioma cell culture established from glioblastoma biopsies induces the expression of B7 and MHC-I antigens in transfected cells (immunogenicity). The transfected cancer cells, “vaccines,” after subcutaneous injection, initiated an immune response mediated by T CD8+ lymphocytes, followed by tumor regression (immunotherapy). The median survival of patients treated by surgery followed by radiotherapy and immunotherapy was 21–24 months. On the other side, the experimental work has demonstrated that IGF-I AS or TH transfected tumor cells fused with activated dendritic cells, DC, showing more striking immunogenic character. Using IGF-I TH/DC “vaccination,” the efficiency in suppressing rat glioma tumors is not only relatively higher than that obtained using IGF-I TH cells but is also more rapid.

Objective: Vaccines for the deadliest brain tumor - glioblastoma (GBM) - are generally based on targeting growth factors or their receptors, often using antibodies. The vaccines described in the review were prepared to suppress the principal cancer growth factor - IGF-I, using anti-gene approaches either of antisense (AS) or of triple helix (TH) type. Our objective was to increase the median survival of patients treated with AS and TH cell vaccines. Methodology: The cells were transfected in vitro by both constructed IGF-I AS and IGF-I TH expression episomal vectors; part of these cells was co-cultured with plant phytochemicals, modulating IGF-I expression. Both AS and TH approaches completely suppressed IGF-I expression and induced MHC-1 / B7 immunogenicity related to the IGF-I receptor signal. Results: This immunogenicity proved to be stronger in IGF-I TH than in IGF-I AS-prepared cell vaccines, especially in TH / phytochemical cells. The AS and TH vaccines generated an important TCD8+ and TCD8+CD11b- immune response in treated GBM patients and increased the median survival of patients up to 17-18 months, particularly using TH vaccines; in some cases, 2- and 3-year survival was reported. These clinical results were compared with those obtained in therapies targeting other growth factors. Conclusion: The anti-gene IGF-I vaccines continue to be applied in current GBM personalized medicine. Technical improvements in the preparation of AS and TH vaccines to increase MHC-1 and B7 immunogenicity have, in parallel, allowed to increase in the median survival of patients.

Glioblastoma multiforme (GBM), a fatal malignant brain tumor, represents a challenge in terms of developing new treatments. Solutions have been proposed in connection with anti-tumor immune responses, generally T cell strategies, including techniques targeting growth factors, particularly IGF-I, the primary cancer growth factor, and its signal transduction pathways. The objective of this review is to assess the immunogene mechanism targeting IGF-I, which constitutes the basis of the described cancer gene therapy for GBM, stemming from brain neoplastic development studies. The GBM gene therapy, based on new strategies of anti-gene IGF-I techniques, including antisense or triple helix, has been combined with phytochemicals (phenolics) and nanotechnologies (theranostic nanoparticles). The three approaches have modulated IGF-I expression together, inducing common signal transduction pathways: IGF-I-R, TK/PI3K/AKT/TLR/MAPK & JAK/STAT. These signals have transformed in vitro neoplastic glioma cells into immunogenic cells. These immunogenic cells, which express MHC-1 and B7, produce a strong T CD8 anti-tumour immune response after in vivo injection. The combined strategy of anti-IGF-I/phytochemical/nanotechnology vaccines has shown promising clinical results, with patient survival of up to two and three years in some cases. The obtained results are discussed in parallel with other immunotherapies and antitumour vaccine studies that involve the immunogenicity mechanism.