Amplification and overexpression of the L-MYC proto-oncogene in ovarian carcinomas
Amplification and overexpression of the L-MYC proto-oncogene in ovarian carcinomas
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DOI：
10.1016/s0002-9440(10)64294-0
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发表时间：
2003-05-01
影响因子：
6
通讯作者：
Cho, KR
中科院分区：
文献类型：
--
作者：
Wu, R;Lin, L;Cho, KR
基因扩增是多种人类癌症（包括卵巢癌（OvCas））中癌基因激活的重要机制。我们使用限制性标志基因组扫描 (RLGS) 来检测 47 个初级 OvCas 基因组中扩增的 DNA 片段。 RLGS 凝胶图像的视觉分析显示，几个 OvCa 样本的斑点强度高于正常组织的相应斑点，表明特定肿瘤中可能存在 DNA 扩增。两个原发性肿瘤（E1和S12）共享四个高强度点。最近开发的一种称为虚拟基因组扫描的信息学工具用于将这些肿瘤中的 RLGS 模式与根据人类基因组序列预测的模式进行比较。虚拟基因组扫描确定四个片段中的三个位于染色体 1p34-35，该区域包含原癌基因 L-MYC。通过定量聚合酶链式反应（PCR）筛选了 68 个原代 OvCas（包括 RLGS 分析的 40 个），以确定 L-MYC 可能的扩增。鉴定出 10 个 L MYC 拷贝数增加的肿瘤，其中包括肿瘤 E1，其显示与正常 DNA 相比，拷贝数增加了 24 倍。对几个肿瘤的 Southern 分析证实了定量 PCR 结果。使用L-MYC侧翼的序列标记位点(STS)标记，发现肿瘤E1中增加的DNA拷贝数跨越D1S432和D1S463之间的L-MYC侧翼区域(大约3.1Mb)。其他肿瘤仅在 L-MYC 基因座处显示扩增。使用寡核苷酸微阵列，发现相对于卵巢表面上皮，L-MYC 在 OvCas 中比 c MYC 或 N-MYC 更频繁地过表达。定量逆转录酶 PCR 分析证实，大部分 OvCas 中 L-MYC 表达升高，包括九个 L-MYC 拷贝数增加的肿瘤中的九个。这些数据表明 L-MYC 基因扩增和/或过度表达在人类 OvCa 发病机制中。
Gene amplification is an important mechanism of oncogene activation in various human cancers, including ovarian carcinomas (OvCas). We used restriction landmark genomic scanning (RLGS) to detect amplified DNA fragments in the genomes of 47 primary OvCas. Visual analysis of the RLGS gel images revealed several OvCa samples with spots of greater intensity than corresponding spots from normal tissues, indicating possible DNA amplification in specific tumors. Two primary tumors (El and S12) shared four high-intensity spots. A recently developed informatics tool termed Virtual Genome Scans was used to compare the RLGS patterns in these tumors with patterns predicted from the human genome sequence. Virtual Genome Scans determined that three of the four fragments localized to chromosome 1p34-35, a region containing the proto-oncogene L-MYC. Sixty-eight primary OvCas, including 40 analyzed by RLGS, were screened by quantitative polymerase chain reaction (PCR) for possible amplification of L-MYC Ten tumors with increased L MYC copy number were identified, including tumor El, which showed an similar to24-fold increase in copy number compared to normal DNA. Southern analysis of several tumors confirmed the quantitative PCR results. Using sequence tagged site (STS) markers flanking L-MYC, increased DNA copy number in tumor El was found to span the region flanking L-MYC between D1S432 and D1S463 (approximate to3.1 Mb). other tumors showed amplification only at the L-MYC locus. Using oligonucleotide microarrays, L-MYC was found to be more frequently overexpressed in OvCas than either c MYC or N-MYC relative to ovarian surface epithelium. Quantitative reverse transcriptase-PCR analysis confirmed elevated L-MYC expression in a substantial fraction of OvCas, including nine of nine tumors with increased L-MYC copy number. The data implicate L-MYC gene amplification and/or overexpression in human OvCa pathogenesis.