Wang Yue, Xue Wei Cheng, Liu Vincent W S, Ngan Hextan Y S
Department of Obstetrics and Gynecology, People's Hospital, Peking University, Beijing, China.
Mitochondrion. 2007 Feb-Apr;7(1-2):171-5. doi: 10.1016/j.mito.2006.11.014. Epub 2006 Dec 5.
Somatic mitochondrial DNA (mtDNA) alterations including point mutations and microsatellite instability (MSI) have been frequently detected in human cancers. To further explore the extensiveness of mtDNA alterations, we have analyzed the occurrence of somatic mtDNA mutations in different populations of endometrial cancer cells from the same tumor tissues as compared with adjacent non-tumor cells. Laser-captured micro-dissection was used to harvest endometrial cancer cells from separated areas of the same tumor and adjacent normal cells. Total DNA isolated from micro-dissected cells was PCR amplified and analyzed for mtDNA alterations by polyacrylamide gel electrophoresis and DNA sequencing. Multiple mtDNA alterations were detected in different portions of the same tumor. Different populations of endometrial cancer cells carried different patterns of mtDNA mutations. Interestingly, unlike previous reports, most mutations were found to be heteroplasmic. We have demonstrated the occurrence of hyper-variability of mtDNA alterations in a single piece of tumor tissue. Our observations support the hypothesis that the accumulation of mtDNA alterations is random and expands independently. The data presented here showed the heterogeneity of cancer cells in terms of mtDNA alterations in endometrial cancer.
包括点突变和微卫星不稳定性（MSI）在内的体细胞线粒体DNA（mtDNA）改变在人类癌症中经常被检测到。为了进一步探究mtDNA改变的广泛性，我们分析了来自同一肿瘤组织的不同群体子宫内膜癌细胞中体细胞mtDNA突变的发生情况，并与相邻的非肿瘤细胞进行比较。利用激光捕获显微切割技术从同一肿瘤的不同区域以及相邻正常细胞中获取子宫内膜癌细胞。从显微切割细胞中分离出的总DNA经聚合酶链反应（PCR）扩增，然后通过聚丙烯酰胺凝胶电泳和DNA测序分析mtDNA改变。在同一肿瘤的不同部分检测到多个mtDNA改变。不同群体的子宫内膜癌细胞携带不同模式的mtDNA突变。有趣的是，与之前的报道不同，大多数突变被发现是异质性的。我们已经证明在单个肿瘤组织中存在mtDNA改变的高度变异性。我们的观察结果支持这样的假说，即mtDNA改变的积累是随机的且独立扩展。此处呈现的数据显示了子宫内膜癌中癌细胞在mtDNA改变方面的异质性。
