Arencibia J M, Schally A V, Halmos G, Nagy A, Kiaris H
Endocrine, Polypeptide and Cancer Institute, Veterans Affairs Medical Center and Tulane University School of Medicine, New Orleans, LA 70112-1262, USA.
Anticancer Drugs. 2001 Jan;12(1):71-8. doi: 10.1097/00001813-200101000-00010.
Targeting of cytotoxic agents represents a modern approach to the treatment of various cancers, that improves the efficacy and reduces peripheral toxicity. Recently we developed a powerful cytotoxic analog of luteinizing hormone-releasing hormone (LHRH), AN-207, designed to be targeted to tumors that express LHRH receptors. This analog consists of the superactive derivative of doxorubicin (DOX), 2-pyrrolino-DOX (AN-201), linked to [D-Lys6]LHRH carrier. In the present study we investigated the cytocidal effects of AN-207 and AN-201 on the LHRH receptor-positive ES-2 ovarian cancer cells. The targeting of AN-207 to ES-2 cells in the presence of LHRH receptor-negative UCI-107 ovarian cancer cells was also evaluated by semi-quantitative polymerase chain reaction (PCR) amplification of microsatellite markers. Ligand competition assays showed a single class of high-affinity and low-capacity binding sites in ES-2 cells with a mean dissociation constant (KD) of 3.93 +/- 0.1 nM and a mean maximal binding capacity (Bmax) of 271 +/- 26.1 fmol/mg membrane protein. Kinetic assays indicated that AN-207 caused cell death in a concentration- and time-dependent manner in ES-2 cells, but not in UCI-107 cells, while the kinetics of cytotoxic effects of AN-201 were similar in both cell lines. To investigate targeting, ES-2 cells were co-cultured with UCI-107 cells, treated with 10 nM AN-207 or AN-201 for different times and then cultured for 48 h in the absence of cytotoxic agents. Genomic DNA was extracted for microsatellite analyses using different markers. Semi-quantitative analyses of the intensity of the alleles that correspond to each cell line indicated that AN-207 was selectively targeted to ES-2 cells, while AN-201 showed no selectivity for either cell line. These results extend our previous findings that AN-207 can be targeted to ovarian cancers and other tumors that express receptors for LHRH. Cytotoxic analogs of LHRH, such as AN-207, should be considered for treatment of LHRH receptor-positive tumors.
靶向细胞毒性药物是治疗多种癌症的现代方法，可提高疗效并降低外周毒性。最近我们开发了一种强大的促黄体生成素释放激素（LHRH）细胞毒性类似物AN-207，其设计目的是靶向表达LHRH受体的肿瘤。该类似物由阿霉素（DOX）的超活性衍生物2-吡咯啉-DOX（AN-201）与[D-Lys6]LHRH载体连接而成。在本研究中，我们研究了AN-207和AN-201对LHRH受体阳性的ES-2卵巢癌细胞的杀伤作用。还通过微卫星标记的半定量聚合酶链反应（PCR）扩增评估了在存在LHRH受体阴性的UCI-107卵巢癌细胞的情况下AN-207对ES-2细胞的靶向作用。配体竞争试验显示ES-2细胞中有一类高亲和力和低容量的结合位点，平均解离常数（KD）为3.93±0.1 nM，平均最大结合容量（Bmax）为271±26.1 fmol/mg膜蛋白。动力学试验表明，AN-207以浓度和时间依赖性方式导致ES-2细胞死亡，但对UCI-107细胞无此作用，而AN-201在两种细胞系中的细胞毒性作用动力学相似。为了研究靶向作用，将ES-2细胞与UCI-107细胞共培养，用10 nM AN-207或AN-201处理不同时间，然后在无细胞毒性药物的情况下培养48小时。提取基因组DNA用于使用不同标记进行微卫星分析。对与每个细胞系相对应的等位基因强度的半定量分析表明，AN-207被选择性地靶向ES-2细胞，而AN-201对两种细胞系均无选择性。这些结果扩展了我们之前的发现，即AN-207可靶向卵巢癌和其他表达LHRH受体的肿瘤。LHRH的细胞毒性类似物，如AN-207，应考虑用于治疗LHRH受体阳性肿瘤。
