ABSTRACT
BACKGROUND & OBJECTIVE: Interleukin-12 (IL-12) is a proinflammatory cytokine with antitumor activity. The study was to compare the therapeutic effects of recombinant murine interleukin-12 (mIL-12) plasmid [pcDNA3.1(+)-mIL-12] and Lewis lung carcinoma (LLC) cell line which could stably express mIL-12 gene in LLC. METHODS: The recombinant plasmid was transfected into LLC cells with lipofectin to obtain LLC/mIL-12 cells which stably express mIL-12 gene. Tumors were established on the right hind leg of C57 BL/6 mice by the subcutaneous injection of 2 x 106 LLC cells. Then all mice were divided into 4 groups (n=10) randomly when the tumors reached 0.5-1.0 cm in diameter. Subsequently, the mice were treated by intratumor injection of pcDNA3.1(+)-mIL-12 plasmid or LLC/mIL-12 vaccine on the first, fourth, and seventh days. Tumor size was measured before and after treatment. Tumor growth curve, CTL and NK activity of spleen cells, and tumor lymphocyte infiltration were observed after all mice were killed on the fourteenth day. RESULTS: Tumor growth were inhibited in mice treated with pcDNA3.1(+)-mIL-12 plasmid or LLC/mIL-12 vaccine; the NK and CTL cell activity was augmented by mIL-12. Overall, the effects were more satisfactory in vaccine group than in plasmid group. There was abundant CD4+ and CD8+ T lymphocyte infiltration observed in both groups. CONCLUSION: mIL-12 in LLC cell line can increase NK cells and CTL. Antitumor immune response could be induced both by pcDNA3.1(+)-mIL-12 plasmid and by LLC/mIL-12 vaccine; the latter one could induce stronger response.
Subject(s)
Cancer Vaccines/therapeutic use , Carcinoma, Lewis Lung/therapy , Interleukin-12/therapeutic use , Animals , Cancer Vaccines/genetics , Carcinoma, Lewis Lung/pathology , Cell Line, Tumor , Cell Proliferation , Female , Immunotherapy , Interferon-gamma/blood , Interleukin-12/genetics , Interleukin-12/metabolism , Killer Cells, Natural/immunology , Mice , Mice, Inbred C57BL , Neoplasm Transplantation , Plasmids , Random Allocation , Recombinant Proteins/genetics , Recombinant Proteins/metabolism , Spleen/cytology , T-Lymphocytes, Cytotoxic/immunology , TransfectionABSTRACT
PURPOSE: The purpose of this study was to determine whether the distribution of radiosensitivities in normal tissues of head and neck cancer patients, measured using a DNA damage assay on lymphocytes, is likely to provide sufficient discrimination to enable reliable identification of patients with abnormal sensitivities. MATERIAL AND METHODS: Radiosensitivity was assessed in 307 lymphocyte samples from unselected head and neck cancer patients and was quantified as the initial number of DNA double-strand breaks (dsb) induced per Gray and per DNA unit (200 Mbp). RESULTS: The existence of an inter-individual variation in the radiosensitivity parameter is described by the range (0.41--9.38 dsb/Gy/DNA unit) of the values found. We detected 37 patients who developed severe skin reactions during radiotherapy treatment and we compared their radiosensitivity values with the remaining patients treated. Radiosensitivity values of >7.20 dsb/Gy/DNA unit should theoretically correspond to highly radiosensitive patients. CONCLUSIONS: Our results suggest that initial DNA damage measured on lymphocytes offers an approach to predict the acute response of human normal tissues prior to radiotherapy. .
Subject(s)
DNA Damage/radiation effects , Head and Neck Neoplasms/genetics , Head and Neck Neoplasms/radiotherapy , Lymphocytes/radiation effects , Radiation Tolerance/genetics , Humans , ROC Curve , Reproducibility of Results , Risk Assessment , Sensitivity and SpecificityABSTRACT
PURPOSE: Repair of radiation-induced DNA damage plays a critical role for both the susceptibility of patients to side effects after radiotherapy and their subsequent cancer risk. The study objective was to evaluate whether DNA repair data determined in vitro are correlated with the occurrence of acute side effects during radiotherapy. EXPERIMENTAL DESIGN: Nasopharyngeal cancer patients receiving radiation therapy were recruited in a prospective epidemiologic study. As an indicator for clinical radiosensitivity, adverse reactions of the skin were recorded. Cryopreserved lymphocytes from 100 study participants were gamma-irradiated with 5 Gy in vitro and analyzed using the alkaline comet assay. Reproducibility of the assay was determined by repeated analysis (n = 22) of cells from a healthy donor. A coefficient of variation of 0.24 was calculated. RESULTS: The various parameters determined to characterize the individual DNA repair capacity showed large differences between patients. Twenty-one patients were identified with considerably enhanced DNA damage induction, and 19 patients exhibited severely reduced DNA repair capacity after 15 and 30 minutes. Eight patients were considered as clinically radiosensitive, indicated by moist desquamation of the skin after a total radiation dose of 70 Gy. CONCLUSIONS: Using the alkaline comet assay as described here, nasopharyngeal cancer patients were identified showing abnormal cellular radiation effects, but this repair deficiency corresponded only at a very limited extent to the acute radiation sensitivity of the skin.
