Belvedere G, Imperatori L, Damia G, Tagliabue G, Meijer C, de Vries E G, D'Incalci M
Istituto di Ricerche Farmacologiche, Mario Negri, Milano, Italy.
Eur J Cancer. 1996 Oct;32A(11):2011-8. doi: 10.1016/0959-8049(96)00235-3.
In order to simulate drug resistance observed in the clinic, two cisplatin-resistant cell lines were produced from a murine ovarian reticulosarcoma, M5076 (M5), by pulse (M5/CDDP) and continuous (M5/CDDPc) treatment with cis-diamminedichloroplatinum(II)(CDDP). These cell lines showed a similar stable low level of resistance (approximately 3-fold) to CDDP and cross-resistance to carboplatin, iproplatin and the new alkylating agent tallimustine, but not to L-PAM (L-phenylalanine mustard) and BCNU (1,3-bis(2-chloroethyl)-1-nitrosourea). Collateral sensitivity to two inhibitors of topoisomerase II, VP16 (etoposide) and doxorubicin (Dox), but cross-resistance to the topoisomerase I inhibitor, camptothecin, were observed. The two cell lines were also sensitive to 5-fluorouracil. No increase in the level of glutathione or activity of glutathione S-transferase could be observed in resistant cells compared with the parental M5 cells. Total DNA platination immediately after treatment was similar in the parental and resistant cell lines. Repair of total DNA platination, measured after 24 h of recovery, was undetectable in M5 and M5/CDDP cells, but was 33% in M5/ CDDPc cells. Initial DNA-interstrand cross-links (DNA-ISC) were six times higher in M5 than in M5/CDDP cells, but 24 h after treatment, both lines had completely repaired this damage. M5/ CDDPc cells did not show formation of DNA-ISC at any time after treatment. The two resistant cell lines were tumorigenic when implanted in mice and resistant to CDDP treatment in vivo. The CDDP resistant tumours were not cross-resistant in vivo to L-PAM, BCNU and Dox, which had been active in vitro, nor to tallimustine, which had been cross-resistant in vitro. Mechanisms of resistance in M5/CDDP and M5-CDDPc seem to be based on a lower formation of DNA-ISC combined, for the latter cell line, with a higher repair capacity for total DNA platination.
为了模拟临床中观察到的耐药性，通过用顺二氨二氯铂（II）（CDDP）进行脉冲处理（M5/CDDP）和连续处理（M5/CDDPc），从鼠卵巢网状肉瘤M5076（M5）产生了两种顺铂耐药细胞系。这些细胞系对CDDP表现出相似的稳定低水平耐药性（约3倍），并对卡铂、异丙铂和新型烷化剂他莫司汀产生交叉耐药，但对L-PAM（L-苯丙氨酸氮芥）和BCNU（1,3-双（2-氯乙基）-1-亚硝基脲）不产生交叉耐药。观察到对两种拓扑异构酶II抑制剂VP16（依托泊苷）和阿霉素（Dox）有协同敏感性，但对拓扑异构酶I抑制剂喜树碱有交叉耐药性。这两种细胞系对5-氟尿嘧啶也敏感。与亲本M5细胞相比，耐药细胞中谷胱甘肽水平或谷胱甘肽S-转移酶活性没有增加。处理后立即进行的总DNA铂化在亲本细胞系和耐药细胞系中相似。在恢复24小时后测量的总DNA铂化修复在M5和M5/CDDP细胞中无法检测到，但在M5/CDDPc细胞中为33%。初始DNA链间交联（DNA-ISC）在M5中比在M5/CDDP细胞中高6倍，但处理后24小时，两个细胞系都已完全修复了这种损伤。M /CDDPc细胞在处理后的任何时间都未显示出DNA-ISC的形成。这两种耐药细胞系植入小鼠后具有致瘤性，并且在体内对CDDP处理具有耐药性。CDDP耐药肿瘤在体内对在体外有活性的L-PAM、BCNU和Dox以及在体外具有交叉耐药性的他莫司汀均无交叉耐药性。M5/CDDP和M5-CDDPc中的耐药机制似乎是基于较低的DNA-ISC形成，对于后一种细胞系，还结合了对总DNA铂化更高的修复能力。
