Xu Rui-Hua, Yuan Zhong-Yu, Guan Zhong-Zhen, Li Su
Skate Key Laboratory of Oncology in Southern China, Cancer Center, Sun Yat-sen University, Guangzhou, Guangdong, P. R. China.
Ai Zheng. 2005 Aug;24(8):975-9.
BACKGROUND & OBJECTIVE: Multidrug resistance is one of the main causes of treatment failure of chemotherapy. Reversal agents may be used to reverse drug-resistance. To date, no appropriate reversal agent is used clinically. This study was to evaluate reverse effect of genetically modified adenovirus H101 on drug-resistance of A549/DDP cells to cisplatin (DDP), and to explore its mechanisms.
Lung adenocarcinoma cell line A549 and its DDP-resistant cell line A549/DDP were treated with DDP and H101. Reverse effect of H101 on drug-resistance of A549/DDP to DDP was tested by MTT assay. The levels of cellular multidrug resistant protein 1 (MRP1), glutathione-S-transferase (GST), and topoisomerase-II (TOPO-II) were detected by flow cytometry (FCM). The level of intracellular glutathione (GSH) was measured by fluorescence-Coomassie light blue method. The intracellular concentration of platinum was measured by atomic absorption spectrometry.
The resistance index of A549/DDP cells to DDP was 14.3. After infection of H101, the 50% inhibitory concentration (IC(50)) of DDP to A549/DDP cells reduced from 352.4 micromol/L to 61.6 micromol/L by 5.7 folds. Protein levels of GST and TOPO-II were higher in A549/DDP cells than in A549 cells, which were markedly decreased in A549/DDP cells after infection of H101. No MRP1 protein was detected in both A549 cells and A549/DDP cells. Intracellular amount of GSH in A549/DDP cells was 2 times higher than that in A549 cells, which was significantly decreased after infection of H101. The concentration of platinum in A549 cells was 3 times higher than that in A549/DDP cells. After infection of H101, the concentration of platinum in A549 cells had no significant change, but that in A549/DDP cells was significantly increased.
H101 may reverse drug-resistance of A549/DDP cells to DDP through down-regulating GST and TOPO-IIand increasing intracellular cumulation of platinum.
多药耐药是化疗治疗失败的主要原因之一。逆转剂可用于逆转耐药性。迄今为止，临床上尚无合适的逆转剂。本研究旨在评估基因修饰腺病毒H101对A549/DDP细胞对顺铂（DDP）耐药性的逆转作用，并探讨其机制。
用DDP和H101处理肺腺癌细胞系A549及其DDP耐药细胞系A549/DDP。采用MTT法检测H101对A549/DDP对DDP耐药性的逆转作用。采用流式细胞术（FCM）检测细胞多药耐药蛋白1（MRP1）、谷胱甘肽-S-转移酶（GST）和拓扑异构酶-II（TOPO-II）的水平。采用荧光-考马斯亮蓝法测定细胞内谷胱甘肽（GSH）水平。采用原子吸收光谱法测定细胞内铂浓度。
A549/DDP细胞对DDP的耐药指数为14.3。感染H101后，DDP对A549/DDP细胞的50%抑制浓度（IC50）从352.4μmol/L降至61.6μmol/L，降低了5.7倍。A549/DDP细胞中GST和TOPO-II的蛋白水平高于A549细胞，感染H101后A549/DDP细胞中这两种蛋白水平明显降低。A549细胞和A549/DDP细胞中均未检测到MRP1蛋白。A549/DDP细胞内GSH含量是A549细胞的2倍，感染H101后明显降低。A549细胞中铂浓度是A549/DDP细胞的3倍。感染H101后，A549细胞中铂浓度无明显变化，但A549/DDP细胞中铂浓度明显升高。
H101可能通过下调GST和TOPO-II以及增加细胞内铂的蓄积来逆转A549/DDP细胞对DDP的耐药性。
