Enhancement of radiotherapy by hyperthermia-regulated gene therapy

Purpose: Interleukin 12 (IL-12) has shown strong antitumoral effects in numerous pre-clinical studies and appears to act synergistically with radiation in murine tumors. The major impediment to its clinical use has been its systemic toxicity. While using intratumorally injected viral gene therapy vectors encoding IL-12 reduces systemic side effects substantially, elevated systemic transgene levels are still observed because adenovirus can reach the circulation. Further restricting IL-12 expression in the tumor is therefore desirable in a combined radiation and adenovirus mediated cancer gene therapy regimen. Methods and Materials: Hyperthermia-regulated gene therapy was tested in a nonimmunogenic B16.F10 melanoma line that is syngeneic with C57BL/6 mice. For hyperthermic gene therapy, an adenoviral vector coding for IL-12 under the control of the promoter of the human heat shock protein 70B (hsp70B) was used. One meek after transplantation (at a 5-7 mm diameter), tumors were irradiated with 3 x 11 Gy (mo-we-fri). Adenovirus was injected at 3 x 10(8) pfu/tumor 24 h before the last radiation fraction or 3 days afterwards. Hyperthermia was performed 24 h later at 42.5 degreesC. Growth delay to reaching 3 times initial tumor volume was chosen as the biologic endpoint. IL-12 levels in tumor and serum were determined by using the enzyme-linked immunosorbant assay (ELISA). Results: Adenovirus mediated intratumoral expression of IL-12 under the control of a heat inducible promoter in combination with hyperthermia is almost as effective as that under the control of a constitutive cytomegaly virus (CMV) promoter while systemic transgene levels are substantially reduced with the heat inducible promoter. The response to radiotherapy is improved considerably when combined with heat inducible gene therapy without apparent systemic toxicity. When used as a single dose, applying IL-12 gene therapy after completion of radiotherapy appears to be beneficial. Conclusion: Hyperthermia-regulated gene therapy in combination with radiation is feasible and therapeutically effective in murine tumors,vith no apparent systemic toxicity. (C) 2000 Elsevier Science Inc

Combination treatment of murine tumors by adenovirus-mediated local B7/IL12 immunotherapy and radiotherapy

Failure of local tumor control still poses a problem for radiotherapy and translates into reduced survival. Combining radiation with chemotherapy or other newer modalities has shown promising results. Immunological approaches to tumor therapy have found renewed interest due to improved insight into mechanisms involved in the immune response to tumors. In this paper, we studied tumor growth delay after various combination regimens of locally injected adenovirus constitutively expressing IL12 and B7.1 (AdIL12/B7.1) and fractionated radiotherapy in two nonimmunogenic murine tumor models, 4T1 and B16.F10. Effects of radiation and virus infection on surface antigen expression in these tumor lines were assessed. Mechanisms of action of AdlL12/B7.1 were studied by conducting additional experiments with and without depletion of NK-cells and/or T-cells, and by cytotoxic T-lymphocyte assays, and immunohistochemical evaluation of tumor blood vessels. Both B7.1 and IL12 were effectively expressed in both irradiated and unirradiated 4T1 and B16.F10 tumor cells but did not add significantly to radiation-induced cell killing in vitro. However, local tumor infection by AdIL12/B7.1 after irradiation significantly increases the effectiveness of radiotherapy when applied after completion of radiotherapy. The mechanism appears to be complicated, involving a host of factors that included the ability of IL12 to activate T-cells and NK-cells and to inhibit angiogenesis and the ability of radiation to induce apoptosis or necrosis among tumor cells. These data support the combination of radiotherapy with adenovirus-mediated immunotherapy and suggest that the concept of adding genetic immunotherapy after radiotherapy in a combined regimen merits further study

Chiroptical properties of cholesteric liquid crystals of chitosan phenylcarbamate in ionic liquids

Chitosan phenylcarbamate (CtsPC) samples were synthesized with different degrees of substitution (DS) ranging from 2.3 to 3.5, and their lyotropic liquid crystallinity in ionic liquids was investigated. 1-Ethyl-3-methylimidazolium dicyanamide ([C2Mim][N(CN)2]) was found to be a novel solvent for CtsPC, and the concentrated lyotropic system formed a cholesteric liquid-crystalline phase and mostly exhibited vivid colorations owing to selective reflection of visible light. Ultraviolet–visible–near-infrared spectroscopy and wide-angle X-ray diffractometry were used to evaluate the maximum wavelength of selective light reflection and the distance and rotational difference between adjacent nematic thin layers in the cholesteric mesophase, respectively. The cholesteric helical pitch increased with decreasing polymer concentration, increasing temperature or increasing DS. The helical sense remained right-handed under the adopted measurement conditions, although CtsPCs are known to form a left-handed cholesteric structure in polar organic solvents, such as N, N-dimethylformamide (DMF). Accordingly, an inversion of the cholesteric sense was achieved by combination of [C2Mim][N(CN)2] and DMF as solvent; circular dichroism and optical rotatory dispersion spectroscopy verified that the sense of CtsPC cholesterics changed from left-handed to right-handed with increasing [C2Mim][N(CN)2] content in the mixed solvent