The approach of triple helix formation in control of gene expression and the treatment of tumors expressing IGF-I

Anti-Gene IGF-I Vaccines in Cancer Gene Therapy: A Review of a Case of Glioblastoma

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.

Chronodisruption in lung cancer and possible therapeutic approaches

A customary temporal organization of physiological functions and biological processes is necessary to maintain body homeostasis and an altered body time structure may favour carcinogenesis. There is growing evidence that GH stimulates cancer growth, IGF1 may have a role in carcinogenesis and cancer promotion, GH-IGF1 axis, TRH, TSH, thyroxine, melatonin and cortisol modulate immune cell function and the immune system is often dysfunctional in patients with malignancies. The aim of our study was to evaluate GH-IGF1 axis, hypothalamus-pituitary-thyroid axis, melatonin, cortisol, lymphocyte subsets and IL2 in lung cancer patients. Peripheral blood samples were collected at 4-hour intervals in a 24-hour period from eleven healthy male subjects (age range 35-53 years) and nine male patients suffering from non-small cell lung cancer (age range 43-63 years). In each blood sample, lymphocyte subpopulations (CD3+, CD4+, CD8+, CD16+, CD20+, CD25+, HLA-DR+, γδTcR bearing cells) were analyzed and GH, IGF1, TRH, TSH, FT4, melatonin, cortisol and IL2 were measured. Circadian rhythmicity was evaluated and MESOR, amplitude and acrophase values were compared. In healthy subjects a significant circadian rhythm could be demonstrated with midday peaks for CD8+, CD16+, γδTCR expressing cells and cortisol, and peaks during the night for CD3+, CD4+, GH, TSH and melatonin. A borderline significant rhythm was also observed for CD20+, with a peak late in the evening. IGF1, TRH, FT4 and IL2 values did not show rhythmic variation. In cancer patients a significant circadian rhythm could be demonstrated with diurnal peak for CD16+ and peaks during the night for CD4+ and melatonin. GH, IGF1, TRH, TSH, FT4, cortisol and IL2 values did not show rhythmic variation. MESOR of CD8+ (P<0.0001), CD20+ (P=0.05), γδTCR expressing cells (P=0.01), IGF1 (P<0.001) and TSH (P=0.032) was higher in healthy subjects, whereas MESOR of CD16+ (P<0.0001), CD25+ (P=0.001), GH (P<0.001), TRH (P=0.002), FT4 (P=0.030), cortisol (P=0.01) and IL2 (P=0.02) was higher in cancer patients. Amplitude of circadian variation of γδTCR expressing cells (P=0.01), TSH (P<0.001) and cortisol (P=0.01) was higher in healthy subjects, whereas amplitude of circadian variation of CD4+ was higher in cancer patients (P=0.02). In conclusion, non-small cell lung cancer patients show severe alterations of periodic and quantitative characteristics of neuroendocrine and immune parameters with loss of circadian rhythmicity and internal desynchronization, leading to chronodisruption.

Stabilizing effect of propionic acid derivative of anthraquinone--polyamine conjugate incorporated into α-β chimeric oligonucleotides on the alternate-stranded triple helix

Two types of anthraquinone conjugates were synthesized as non-nucleosidic oligonucleotide components. These include an anthraquinone derivative conjugated with 2,2-bis(hydroxymethyl)propionic acid and an anthraquinone--polyamine derivative conjugated with 2,2-bis(hydroxymethyl)propionic acid. The conjugates were successfully incorporated into the "linking-region" of the α-β chimeric oligonucleotides via phosphoramidite method as non-nucleosidic backbone units. The resultant novel α-β chimeric oligonucleotides possessed two diastereomers that were generated by the introduction of the anthraquinone conjugate with a stereogenic carbon atom. The isomers were successfully separated by a reversed-phase HPLC. UV-melting experiments revealed that both stereoisomers formed a substantially stable alternate-strand triple helix, irrespective of the stereochemistry of the incorporated non-nucleosidic backbone unit. However, the enhancing effect on thermal stability depended on the length of the alkyl linker connecting anthraquinone moiety and the propionic acid moiety. The sequence discrimination ability of the chimeric oligonucleotides toward mismatch target duplex was also examined. The T(m) values of the triplexes containing the mismatch target were substantially lower than the T(m) values of those containing the full-match target. The thermodynamic parameters (ΔH°, ΔS°, and ΔG°) required for the dissociation of the triplexes into the third strand and target duplex were also measured.

Endocrine aspects of cancer gene therapy

The field of cancer gene therapy is in continuous expansion, and technology is quickly moving ahead as far as gene targeting and regulation of gene expression are concerned. This review focuses on the endocrine aspects of gene therapy, including the possibility to exploit hormone and hormone receptor functions for regulating therapeutic gene expression, the use of endocrine-specific genes as new therapeutic tools, the effects of viral vector delivery and transgene expression on the endocrine system, and the endocrine response to viral vector delivery. Present ethical concerns of gene therapy and the risk of germ cell transduction are also discussed, along with potential lines of innovation to improve cell and gene targeting.

Animal transgenesis: recent data and perspectives

Gene transfer to generate transgenic animals is used more and more to study gene regulation and function. It is also an essential tool to prepare pharmaceuticals or pig organs for transplantation to humans. It is also expected to be a potent way to generate farm animals having traits that cannot emerge by conventional selection. During the last few years, the different techniques to generate transgenic animals and obtain a well-controlled expression of the transgenes have been quite significantly improved. This paper is a brief summary of the most recent relevant data in this field.

Insulin-like growth factor-I receptor - a potential therapeutic target in medulloblastomas

Medulloblastomas represent nearly 25% of all paediatric intracranial neoplasms. These highly malignant tumours arise from the cerebellum and affect predominantly children between the ages of 5 and 15. Although the aetiology of medulloblastomas has not been elucidated, several reports show that the insulin-like growth factor-I (IGF-I) signalling system is highly activated in medulloblastoma cell lines, medulloblastoma animal models and medulloblastoma biopsies, suggesting its contribution to the development and/or progression of these tumours. In addition, reports from multiple laboratories confirm a critical role for the IGF-I receptor (IGF-IR) in the process of cellular transformation. Taken together, these observations prompt the investigation of different strategies to impair the function of IGF-IR as a potential therapeutic tool, which by compromising growth and survival of medulloblastoma cells could supplement conventional therapeutic regiments against these malignant neoplasms of childhood.

The methods to generate transgenic animals and to control transgene expression

Transgenic animals have been used for years to study gene function and to create models for the study of human diseases. This approach has become still more justified after the complete sequencing of several genomes. Transgenic animals are ready to become industrial bioreactors for the preparation of pharmaceuticals in milk and probably in the future in egg white. Improvement of animal production by transgenesis is still in infancy. Despite its intensive use, animal transgenesis is still suffering from technical limitations. The generation of transgenics has recently become easier or possible for different species thanks to the use of transposons or retrovirus, to incubation of sperm which DNA followed by fertilization by intracellular sperm injection or not and to the use of the cloning technique using somatic cells in which genes have been added or inactivated. The Cre-LoxP system is more and more used to withdraw a given sequence from the genome or to target the integration of a foreign DNA. The tetracycline system has been improved and can more and more frequently be used to obtain faithful expression of transgenes. Several tools: RNA forming a triple helix with DNA, antisense RNA including double strand RNA inducing RNA interference and ribozymes, and also expression of proteins having a negative transdominant effect, are tentatively being improved to inhibit specifically the expression of host or viral genes.All these techniques are expected to offer experimenters new and more precise models to study gene function even in large animals. Improvement of breeding by transgenesis has become more plausible including through the precise allele replacement in farm animals.

Oligonucleotides containing a lysine residue as 3'-3' junction for alternate strand triple helix formation

Oligonucleotides with a 3'-3' inversion of polarity site assured by one lysine residue have been synthesized, characterized and used as third strands in alternate strand triple helix formation. UV melting studies and molecular mechanics calculations have been carried out to investigate the stability and the geometry of these new triplexes.