预热对K_(562)细胞化疗药物体外敏感性的影响

目的：研究预热对肿瘤细胞化疗药物敏感性的影响并初步探讨其可能机理。方法：对Ｋ５６２细胞预热应激，用ＲＴ－ＰＣＲ检测细胞热应激蛋白７０（ＨＳＰ７０），并用ＭＴＴ比色法观察细胞对化疗药物体外敏感性的变化。结果：预热使Ｋ５６２细胞ＨＳＰ７０明显增多，且在预热２ｈ后达到最高；在常规剂量下（临床一次用量的１／２５０）未预热Ｋ５６２细胞对阿霉素（ＡＤＭ，０．４ｍｇ／Ｌ）及环磷酰胺（ＣＴＸ，０．８ｍｇ／Ｌ）中度敏感；预热应激后，Ｋ５６２细胞对这两种同剂量药物均轻度敏感或不敏感；并检测了这两种药物的浓度梯度。结论：热应激可以降低肿瘤细胞对化疗药物的敏感性；推测ＨＳＰ７０表达增强可能是肿瘤热疗效果和化疗药物敏感性降低的直接原因。

Preheating decrease the sensitivity of K 562 cell to chemotheraputic drugs

Hyperthermia is a powerful tool for enhancing the effect of many chemical drugs on killing cells, but too many times of hyperthermia could decrease the effect and increase the ability of tumor cell against chemical drugs. Heat stress protein 70(HSP70) mRNA of K562 cell was analyzed by RT-PCR, and the chemosensitivity of K562 cell was tested by MTT method before and after heat-exposure. The results showed that HSP70 mRNA increased greatly after K562 cells exposed to 40 degrees C for 30 min and then it went to the top after 120 min heat-exposure. The sensitivity of K562 cell to adriamycin (ADM) and cyclophosphamide (CTX) in a usual dosage (1/250 of one dosage in clinical use) was in middle degree before exposed to heat, and the sensitivity dramatically went down after K562 cell being heat-stressed. The sensitivity of heat-stressed tumor cells to chemotherapeutic drugs was decreased, which may come from the increased expression of stress proteins in cells.