Reduced endocytosis and altered lysosome function in cisplatin-resistant cell lines.
Reduced endocytosis and altered lysosome function in cisplatin-resistant cell lines.
复制标题
DOI：
10.1038/sj.bjc.6600861
复制
发表时间：
2003-04-22
影响因子：
8.8
通讯作者：
中科院分区：
文献类型：
--
作者：
我们分离出人KB腺癌顺铂耐药（CP-r）细胞系，由于顺铂和其他细胞毒性化合物（如甲氨蝶呤和重金属）的积累减少，具有多药耐药表型。辣根过氧化物酶（HRPO）和得克萨斯红葡聚糖的摄取在KB-CP-r细胞中降低了几倍，表明液相内吞的一般缺陷。相反，虽然EGF受体的量减少，EGF吸收的动力学，受体介导的内吞作用的标志物，在敏感和耐药细胞是相似的。然而，40-60%的125 I-EGF释放到介质中摄取到KB-CP-r细胞的溶酶体后，TCA沉淀相比，只有10%的敏感细胞释放。这些结果表明，KB-CP-r细胞的溶酶体中内化的125 I-EGF的降解效率低，与溶酶体半胱氨酸蛋白酶组织蛋白酶L的加工较慢一致。用巴弗洛霉素A1（一种已知的空泡质子泵抑制剂）处理KB细胞，模拟了在KB-CP-r细胞中观察到的表型，HRPO、125 I-EGF、14 C-卡铂的摄取减少，TCA可沉淀125 I-EGF的释放减少。KB-CP-r细胞也有较低的酸性溶酶体。KB-CP-r细胞对假单胞菌外毒素具有交叉耐药，而假单胞菌外毒素耐药的KB细胞对顺铂具有交叉耐药。由于已知具有内体酸化缺陷的细胞对假单胞菌外毒素具有抗性，并且内体酸化的阻断模拟CP-r表型，因此我们得出结论，内体酸化缺陷可能有助于获得性顺铂抗性。
We isolated human KB adenocarcinoma cisplatin-resistant (CP-r) cell lines with multidrug-resistance phenotypes because of reduced accumulation of cisplatin and other cytotoxic compounds such as methotrexate and heavy metals. The uptake of horseradish peroxidase (HRPO) and Texas Red dextran was decreased several-fold in KB-CP-r cells, indicating a general defect in fluid-phase endocytosis. In contrast, although EGF receptors were decreased in amount, the kinetics of EGF uptake, a marker of receptor-mediated endocytosis, was similar in sensitive and resistant cells. However, 40–60% of the 125I-EGF released into the medium after uptake into lysosomes of KB-CP-r cells was TCA precipitable as compared to only 10% released by sensitive cells. These results indicate inefficient degradation of internalised 125I-EGF in the lysosomes of KB-CP-r cells, consistent with slower processing of cathepsin L, a lysosomal cysteine protease. Treatment of KB cells by bafilomycin A1, a known inhibitor of the vacuolar proton pump, mimicked the phenotype seen in KB-CP-r cells with reduced uptake of HRPO, 125I-EGF, 14C-carboplatin, and release of TCA precipitable 125I-EGF. KB-CP-r cells also had less acidic lysosomes. KB-CP-r cells were crossresistant to Pseudomonas exotoxin, and Pseudomonas exotoxin-resistant KB cells were crossresistant to cisplatin. Since cells with endosomal acidification defects are known to be resistant to Pseudomonas exotoxin and blocking of endosomal acidification mimics the CP-r phenotype, we conclude that defective endosomal acidification may contribute to acquired cisplatin resistance.
登录
查看更多内容
影响因子：
6.4
作者：
Murakami, T;Shibuya, I;Kohno, K
通讯作者：
Kohno, K
影响因子：
56.9
作者：
KELLEY, SL;BASU, A;LAZO, JS
通讯作者：
LAZO, JS
DOI：
10.1073/pnas.89.7.3070
发表时间：
1992-04-01
影响因子：
11.1
作者：
GODWIN, AK;MEISTER, A;ANDERSON, ME
通讯作者：
ANDERSON, ME
影响因子：
3.7
作者：
Johnson, SW;Shen, DW;Hamilton, TC
通讯作者：
Hamilton, TC
影响因子：
2.9
作者：
Chauhan, SS;Ray, D;Gottesman, MM
通讯作者：
Gottesman, MM