Withoff S, van der Zee A G, de Jong S, Hollema H, Smit E F, Mulder N H, de Vries E G
Division of Medical Oncology, University Hospital Groningen, The Netherlands.
Br J Cancer. 1999 Feb;79(5-6):748-53. doi: 10.1038/sj.bjc.6690120.
To study DNA topoisomerase IIalpha (Topo-IIalpha) and -beta expression and regulation in human ovarian cancer, 15 ovarian tumour samples were investigated. To compare different levels of expression, the samples were screened for topo IIalpha and -beta mRNA with Northern blotting and a quantitative reverse transcriptase polymerase chain reaction (RT-PCR) assay for Topo-IIalpha mRNA. Additionally, protein levels were determined with Western blotting and topoisomerase II activity levels with the decatenation assay. The results obtained were compared with each other and with the tumour volume index of the samples. In tumours with a tumour volume index > or = 50%, the mRNA levels (as determined by Northern blotting) and protein levels for each isozyme were in accordance. Additionally, correlations were found between Topo-IIalpha RT-PCR data and Topo-IIalpha Northern blot results, and between Topo-IIalpha RT-PCR data and Topo-IIalpha protein levels. Interestingly, Topo-IIbeta protein levels correlated better with Topo-II activity than Topo-IIalpha protein levels. In eight ovarian cystadenoma samples, no Topo-IIalpha protein could be found. In only three out of eight of these cystadenomas, Topo-IIbeta protein could be detected. These findings suggest that Topo-IIalpha and Topo-IIbeta protein levels are up-regulated in ovarian cancer and may indicate that Topo-IIbeta is an interesting target for chemotherapy in ovarian tumours.
为研究DNA拓扑异构酶IIα（Topo-IIα）和-β在人类卵巢癌中的表达及调控情况，对15份卵巢肿瘤样本进行了研究。为比较不同的表达水平，采用Northern印迹法对样本进行Topo IIα和-β mRNA筛查，并采用定量逆转录聚合酶链反应（RT-PCR）法检测Topo-IIα mRNA。此外，通过蛋白质印迹法测定蛋白质水平，并采用解连环测定法检测拓扑异构酶II活性水平。将所得结果相互比较，并与样本的肿瘤体积指数进行比较。在肿瘤体积指数≥50%的肿瘤中，每种同工酶的mRNA水平（通过Northern印迹法测定）和蛋白质水平一致。此外，在Topo-IIα RT-PCR数据与Topo-IIα Northern印迹结果之间，以及在Topo-IIα RT-PCR数据与Topo-IIα蛋白质水平之间均发现了相关性。有趣的是，Topo-IIβ蛋白质水平与Topo-II活性的相关性比Topo-IIα蛋白质水平更好。在8份卵巢囊腺瘤样本中，未检测到Topo-IIα蛋白质。在这8份囊腺瘤中，仅3份检测到了Topo-IIβ蛋白质。这些发现表明，Topo-IIα和Topo-IIβ蛋白质水平在卵巢癌中上调，这可能表明Topo-IIβ是卵巢肿瘤化疗的一个有意义的靶点。
