The Basic Study of Multidisciplinary Treatment for Malignant Tumors using MnSOD Gene Therapy

1)我们利用MnSOD基因转染的纤维肉瘤细胞系FSa-II证实了MnSOD基因过表达增加了放射治疗、热疗和化疗的体内效应。2) scid小鼠实验发现，过表达MnSOD基因可抑制小鼠纤维肉瘤FSa-II的自发凋亡，但不影响其体内生长。3)新建立的显微系统显示，MnSOD基因过表达增加了高温处理后细胞的凋亡。4) MnSOD基因过表达对细胞的移动能力无明显影响。5)体内电穿孔基因转染后细胞内MnSOD活性随着DNA浓度从5 ~ 50 μg/6μl的升高而升高，并在转染后第3天达到峰值。6)体内电穿孔转染MnSOD基因增加了放疗和热疗的体内效应。采用体内电穿孔法转染MnSOD基因，用于C3H/He小鼠FSa-II肿瘤。基因转染后第3天，肿瘤按分级剂量照射或44℃加热60 min。采用肿瘤生长-50法和肿瘤控制剂量-50法分析治疗效果。本研究表明，MnSOD过表达提高了细胞在体外的热敏性，大大降低了肿瘤的致瘤性，导致体内肿瘤生长时间明显延长。MnSOD过表达降低了肿瘤的致瘤性，也显著提高了体内放疗的肿瘤控制率。

1) We confirmed that MnSOD gene overexpression increased the in vivo effects of radiotherapy, hyperthermia, and chemotherapy, using MnSOD gene-tranfected fibrosarcoma cell line, FSa-II.2) Experiments using scid mice revealed that overexpression of MnSOD gene suppressed spontaneous apoptosis without a resultant alteration in in vivo growth of the mouse fibrosarcoma, FSa-II.3) Newly developed microscopic system was available to indicate that MnSOD gene overexpression increased apoptosis after hyperthermic treatments.4) In vitro timelapse microscopic observation of cellular moving ability did not show any difference by MnSOD gene overexpression.5) Intracellular MnSOD activity following gene-transfection by in vivo electroporation increased as concentration of DNA increased from 5 to 5Oμg/6μl, and reached peak at third day after transfection.6) MnSOD gene-transfection by in vivo electroporation increased the in vivo effects of radiotherapy and hyperthermia. MnSOD gene was transfected by in vivo electroporation for FSa-II tumor in C3H/He mice. Tumors were irradiated at graded doses or heated at 44℃ for 60 min at third day after gene-transfection. The effects of treatments were analyzed by tumor growth-50 method and tumor control dose-50 method.This study indicated that MnSOD overexpression increased thermosensitivity of cells in vitro, and substantially reduces the tumorigenicity, resulting in a significant increase in tumor growth time in vivo. Reduced tumorigenicity by MnSOD overexpression also resulted in a significant increase in tumor control rate by radiotherapy in vivo.