Masumoto N, Nakano S, Fujishima H, Kohno K, Niho Y
First Department of Internal Medicine, Faculty of Medicine, Kyushu University, Fukuoka, Fukuoka, Japan.
Int J Cancer. 1999 Mar 1;80(5):731-7. doi: 10.1002/(sici)1097-0215(19990301)80:5<731::aid-ijc17>3.0.co;2-h.
Activation of Src, which has an intrinsic protein tyrosine kinase (PTK) activity, has been demonstrated in human solid tumors, such as colorectal and breast cancers. To investigate the role of activated Src in drug resistance, we evaluated the effect of v-src on the resistance to various anti-cancer drugs using v-src-transfected HAG-1 human gallbladder adenocarcinoma cells. Compared with parental or mock-transfected HAG-1 cells, v-src-transfected HAG/src3-1 cells showed a 3.5-fold resistance to cis-diamminedichloroplatinum (II) (CDDP) but not to doxorubicin, etoposide or 5-fluorouracil. By contrast, activated H-ras, which acts downstream of src, failed to induce resistance to either of these drugs. Furthermore, wortmannin, a phosphatidylinositol (PI) 3-kinase inhibitor, and H7, a protein kinase C (PKC) inhibitor, did not alter CDDP resistance. Evaluation of the kinetics of the removal of DNA interstrand cross-links (ICLs), measured by alkaline elution, showed a significant increase in this removal in HAG/src3-1 cells as compared with mock-transfected cells, though no differences were found in the formation of DNA ICLs between these cell lines. CDDP resistance in v-src-transfected cells was reversed, if not completely, by either herbimycin A or radicicol, specific inhibitors of Src-family PTKs, suggesting that Src tyrosine kinase activity induces CDDP resistance. Moreover, significant reduction in the repair of CDDP-induced DNA ICLs was observed upon treatment with radicicol. The intracellular glutathione content and mRNA expression of topoisomerase II and metallothionein were virtually identical between these cell lines, except for topoisomerase I mRNA. Our data strongly suggest that the ability of activated src, but not ras, to induce CDDP resistance is mediated by augmentation of DNA repair through Src to downstream signal-transduction pathways distinct from either the Ras, PI 3-kinase or PKC pathway.
具有内在蛋白酪氨酸激酶（PTK）活性的Src激活已在人类实体瘤中得到证实，如结直肠癌和乳腺癌。为了研究激活的Src在耐药性中的作用，我们使用v-src转染的HAG-1人胆囊腺癌细胞评估了v-src对各种抗癌药物耐药性的影响。与亲本或mock转染的HAG-1细胞相比，v-src转染的HAG/src3-1细胞对顺二氨二氯铂（II）（CDDP）表现出3.5倍的耐药性，但对阿霉素、依托泊苷或5-氟尿嘧啶没有耐药性。相比之下，在src下游起作用的激活的H-ras未能诱导对这些药物中任何一种的耐药性。此外，磷脂酰肌醇（PI）3-激酶抑制剂渥曼青霉素和蛋白激酶C（PKC）抑制剂H7并没有改变CDDP耐药性。通过碱性洗脱测量DNA链间交联（ICL）去除动力学的评估表明，与mock转染细胞相比，HAG/src3-1细胞中这种去除显著增加，尽管这些细胞系之间在DNA ICL形成上没有差异。Src家族PTK的特异性抑制剂赫曲霉素A或radicicol可逆转v-src转染细胞中的CDDP耐药性，即使不是完全逆转，这表明Src酪氨酸激酶活性诱导了CDDP耐药性。此外，用radicicol处理后，观察到CDDP诱导的DNA ICL修复显著减少。除拓扑异构酶I mRNA外，这些细胞系之间的细胞内谷胱甘肽含量以及拓扑异构酶II和金属硫蛋白的mRNA表达几乎相同。我们的数据强烈表明，激活的src而非ras诱导CDDP耐药性的能力是通过Src增强DNA修复介导的，该修复作用于不同于Ras、PI 3-激酶或PKC途径的下游信号转导途径。
