Mueller Sandra, Hartmann Ulrike, Mayer Frank, Balabanov Stefan, Hartmann Joerg T, Brummendorf Tim H, Bokemeyer Carsten
Department of Oncology, Hematology, Immunology and Rheumatology, Medical Center, University of Tuebingen, Tuebingen, Germany.
Invest New Drugs. 2007 Dec;25(6):519-24. doi: 10.1007/s10637-007-9063-6. Epub 2007 May 30.
Germ cell tumors (GCT) possess a high activity of telomerase, a ribonucleoprotein complex compensating the erosion of telomeres during cell division by adding TTAGGG-repeats to the telomeric ends of chromosomes. Cisplatin, the most important drug in the treatment of GCT, preferentially acts on G-rich regions like telomeres. Inhibiting telomerase in tumors can result in telomere shortening and senescence and could increase the efficacy of chemotherapy in refractory patients. The study evaluated the promise of the small molecule telomerase inhibitor BIBR1532 as single agent and assessed a possible synergism with cisplatin in a preclinical model of GCT.GCT-derived cell line 2102EP was cultured with or without 10 microM of BIBR1532. Cell expansion was quantified in population doublings (PD). Telomere length was analyzed by fluorescence in situ hybridization and flow cytometry (flow-FISH). The sensitivity of the cells towards cisplatin was determined by MTT-assay. Telomerase activity was assessed by TRAP assay. After 300 PD, telomere length diminished from 18.5 kb +/- 0.59 kb to 8.9 +/- 0.1 kb in BIBR1532 treated 2102 EP cells as compared to 14.5 +/- 0.0 kb in untreated control cells. Treated cells did not show altered growth kinetics compared to untreated counterparts. Despite effective shortening of telomeres, the sensitivity of the treated cells towards cisplatin did not increase. Concomitant treatment with BIBR1532 and cisplatin did not result in accelerated telomere shortening. Telomere length can be shortened significantly by telomerase inhibition in GCT cell line models. However, possibly in view of their extensive telomere "reserve," telomerase inhibition did neither result in increased sensitivity of 2102 EP cells to cisplatin nor did co-treated cells show accelerated telomere shortening.
生殖细胞肿瘤（GCT）具有较高的端粒酶活性，端粒酶是一种核糖核蛋白复合物，通过向染色体的端粒末端添加TTAGGG重复序列来补偿细胞分裂过程中端粒的侵蚀。顺铂是治疗GCT最重要的药物，它优先作用于富含鸟嘌呤的区域，如端粒。抑制肿瘤中的端粒酶可导致端粒缩短和细胞衰老，并可能提高难治性患者化疗的疗效。本研究评估了小分子端粒酶抑制剂BIBR1532作为单一药物的前景，并在GCT的临床前模型中评估了其与顺铂可能存在的协同作用。将GCT来源的细胞系2102EP在添加或不添加10微摩尔BIBR1532的情况下进行培养。通过群体倍增（PD）对细胞增殖进行定量。通过荧光原位杂交和流式细胞术（流式荧光原位杂交）分析端粒长度。通过MTT法测定细胞对顺铂的敏感性。通过端粒重复序列扩增法（TRAP）评估端粒酶活性。经过300次群体倍增后，与未处理的对照细胞中端粒长度为14.5±0.0千碱基相比（kb），用BIBR1532处理的2102EP细胞中端粒长度从18.5 kb±0.59 kb减少到8.9±0.1 kb。与未处理的细胞相比，处理后的细胞未显示出生长动力学的改变。尽管端粒有效缩短，但处理后的细胞对顺铂的敏感性并未增加。BIBR1532和顺铂联合处理并未导致端粒加速缩短。在GCT细胞系模型中，通过抑制端粒酶可显著缩短端粒长度。然而，可能鉴于其广泛的端粒“储备”，抑制端粒酶既未导致2102EP细胞对顺铂的敏感性增加，联合处理的细胞也未显示出端粒加速缩短。
