De Vincenzo R, Scambia G, Benedetti Panici P, Fattorossi A, Bonanno G, Ferlini C, Isola G, Pernisco S, Mancuso S
Laboratory of Antinoplastic Pharmacology, Department of Obstetrics and Gynecology, Catholic University, Rome, Italy.
Int J Cancer. 1996 Nov 4;68(3):340-8. doi: 10.1002/(SICI)1097-0215(19961104)68:3<340::AID-IJC12>3.0.CO;2-C.
In this study the ability of the new pure anti-estrogen ICI 182,780 to modulate the cytotoxic action of adriamycin (ADR) on parental and ADR-resistant MCF-7 (MCF-7 ADRr) human breast-cancer cells was investigated and compared with that of tamoxifen (TAM). TAM enhanced ADR cytotoxicity in MCF-7 ADRr cells in a dose-related manner, but this effect was slight or absent in MCF-7 WT. In contrast, ICI 182,780 was able to enhance ADR toxicity both in MCF-7 ADRr and in the parental cell line. ICI 182,780 was up to 2.5-fold more effective than TAM in reducing the IC50 of ADR in MCF-7 ADRr cells. Analysis of the data by the isobole method showed that the combination ADR/TAM and ADR/ICI 182,780 produced synergistic anti-proliferative activity in MCF-7 ADRr cells. Because ADR resistance in these cells is associated with the expression of high levels of P-glycoprotein (Pgp), we evaluated the effect of anti-estrogens on Pgp expression and activity. Both ICI 182,780 and TAM failed to modulate Pgp expression as assessed by flow cytometry and Western-blot analysis, performed using the monoclonal antibodies MM4.17 and C 219, which are specific for an external or an internal determinant respectively. Pgp activity was investigated by flow cytometry measuring the extrusion of ADR and the cationic dye Rhodamine 123 (Rh 123). ICI 182,780, but not TAM, reduced the activity of Pgp in MCF-7 ADRr cells. Flow cytometry was also used to investigate cell-cycle modifications induced by ADR in MCF-7 ADRr cells, both in the presence and in the absence of anti-estrogens. After 72 hr, higher doses induced an arrest of cells at the G2/M phase. The same effect was visible when lower doses of ADR were combined with ICI 182,780 or TAM. In terms of cell-cycle-blocking activity ICI 182,780 was largely more effective than TAM.
在本研究中，研究了新型纯抗雌激素ICI 182,780调节阿霉素（ADR）对亲代及阿霉素耐药的MCF-7（MCF-7 ADRr）人乳腺癌细胞的细胞毒性作用的能力，并与他莫昔芬（TAM）进行了比较。TAM以剂量相关的方式增强了MCF-7 ADRr细胞中ADR的细胞毒性，但在MCF-7野生型细胞中这种作用轻微或不存在。相反，ICI 182,780能够增强MCF-7 ADRr细胞和亲代细胞系中ADR的毒性。在降低MCF-7 ADRr细胞中ADR的IC50方面，ICI 182,780的效果比TAM高2.5倍。用等效线法分析数据表明，ADR/TAM和ADR/ICI 182,780组合在MCF-7 ADRr细胞中产生协同抗增殖活性。由于这些细胞中的阿霉素耐药性与高水平P-糖蛋白（Pgp）的表达相关，我们评估了抗雌激素对Pgp表达和活性的影响。通过流式细胞术和蛋白质印迹分析评估，使用分别针对外部或内部决定簇的单克隆抗体MM4.17和C 219，ICI 182,780和TAM均未能调节Pgp表达。通过流式细胞术测量ADR和阳离子染料罗丹明123（Rh 123）的外排来研究Pgp活性。ICI 182,780而非TAM降低了MCF-7 ADRr细胞中Pgp的活性。流式细胞术还用于研究在有和没有抗雌激素存在的情况下，ADR在MCF-7 ADRr细胞中诱导的细胞周期变化。72小时后，较高剂量诱导细胞在G2/M期停滞。当低剂量的ADR与ICI 182,780或TAM联合使用时，也可见相同的效果。就细胞周期阻滞活性而言，ICI 182,780比TAM有效得多。
