Analysis of Thermotolerance of Cancer by Introduction of Oncogeges

热疗作为一种新的癌症治疗方法被引入。由于肿瘤的热敏性变化10倍，不能将所有的肿瘤都应用于热疗。细胞的癌变是由突变的癌基因表达诱导的。我们将癌基因导入正常细胞，获得转化细胞，并检测细胞的热敏感性，分析决定热敏感性的癌基因。这项研究将在治疗前预测热疗治疗癌症的结果，并选择最有效的治疗方法。在这项研究中，使用小鼠培养的细胞NIH3T3作为正常细胞。将myc、ki-ras、N-ras、H-ras、int-2、fgr、sis和sr5癌基因导入正常细胞，获得转化细胞，检测转化细胞和正常细胞对44ﾟC的温度敏感性。经KI-ras基因转化的细胞对高温具有耐受性。这意味着KI-ras诱导的肿瘤不宜用高温治疗。对上述转化细胞进行了44ﾟC处理15min的耐热性检测。Ha-ras转化细胞4小时耐热率为2.06，是受检细胞中最小的。这意味着，Ha-ras诱导的肿瘤适合采用分次热疗。

Hyperthermia is introduced as a new modality of cancer treatment. As thermosensitivity varies to tumors in ten times, all tumors can not be applied to hyperthermia. Oncogenesis of cells is induced by expression of mutated oncogenes. We introduced oncogenes to normal cells and obtained transformed cells, and examined thermosensitivity of cells, analyzing oncogenes which determine thermosensitivity. This study will predict results of cancer treatment by hyperthermia before its treatment, and most effective treatment would be selected.In this study, mouse cultured cells, NIH3T3, were used for normal cells. Following oncogenes were introduced to normal cells and obtained transformed cells : myc, Ki-ras, N-ras, H-ras, int-2, fgr, sis, and src.Thermosensitivity of transformed cells as well as normal cells to 44ﾟC was examined. The transformed cells by Ki-ras showed resistant to hyperthermia. This means that tumors induced by Ki-ras is not desirable to treat by hyperthermia.Thermotolerance induced by the treatment of 44ﾟC,for 15 min was examined for above transformed cells. The thermotolerant ratio analyzed at 4 hour-interval was 2.06 for transformed cells by Ha-ras which was the smallest in examined cells. This means that tumors induced by Ha-ras is desirable to treat by fractionated hyperthermia.