A novel amplicon at 8p22-23 results in overexpression of cathepsin B in esophageal adenocarcinoma
A novel amplicon at 8p22-23 results in overexpression of cathepsin B in esophageal adenocarcinoma
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DOI：
10.1073/pnas.95.21.12410
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发表时间：
1998-10-13
影响因子：
11.1
通讯作者：
Hanash, S
中科院分区：
文献类型：
--
作者：
Hughes, SJ;Glover, TW;Hanash, S
组织蛋白酶 B (CTSB) 在肺癌、前列腺癌、结肠癌、乳腺癌和胃肿瘤中过度表达。然而，尚缺乏肿瘤发生或进展过程中 CTSB 基因主要基因组改变的证据。我们在 8p22-23 发现了一个新的扩增子，它导致食管腺癌中 CTSB 过度表达。通过二维 DNA 电泳鉴定扩增的基因组 NotI-HinfI 片段。克隆了两个扩增片段（D4 和 D5）并产生了独特的序列。使用含有 D4 或 D5 的细菌人工染色体克隆，荧光原位杂交确定了涉及染色体带 8p22-23 的单个扩增区域，我们研究了候选癌症相关基因 CTSB，以及来自该区域的潜在共扩增基因，包括法呢基二磷酸法呢基转移酶 (FDFT1)、芳基胺 N-乙酰转移酶 (NAT-I)、脂蛋白脂肪酶 (LPL) 和未表征的表达序列标签 (D8S503)。对 66 例食管腺癌的 Southern 印迹分析表明，只有 CTSB 和 FDFT1 在 8 例 (12.1%) 肿瘤中一致扩增。 NAT-1 和 LPL 都没有被扩增。 Northern 印迹分析显示，在分析的所有六种扩增食管腺癌中，CTSB 和 FDFT1 mRNA 过度表达。 CTSB mRNA 过度表达也存在于所分析的六个非扩增肿瘤中的两个中。然而，没有观察到 FDFT1 mRNA 过表达而不扩增。蛋白质印迹分析证实，与正常对照或没有 mRNA 过表达的肿瘤相比，CTSB mRNA 过表达的肿瘤标本中 CTSB 蛋白过表达。通过免疫组织化学分析，40 例食管腺癌标本中的 29 例（72.5%）发现 CTSB 蛋白在细胞外大量表达。在 8p22-23 处发现的扩增子导致 CTSB 基因扩增和过度表达，这支持了 CTSB 在食管腺癌以及可能在其他肿瘤中的重要作用。
Cathepsin B (CTSB) is overexpressed in tumors of the lung, prostate, colon, breast, and stomach. However, evidence of primary genomic alterations in the CTSB gene during tumor initiation or progression has been lacking. We have found a novel amplicon at 8p22-23 that results in CTSB overexpression in esophageal adenocarcinoma. Amplified genomic NotI-HinfI fragments were identified by two-dimensional DNA electrophoresis. Two amplified fragments (D4 and D5) were cloned and yielded unique sequences. Using bacterial artificial chromosome clones containing either D4 or D5, fluorescent in situ hybridization defined a single region of amplification involving chromosome bands 8p22-23, We investigated the candidate cancer-related gene CTSB, and potential coamplified genes from this region including farnesyl-diphosphate farnesyltransferase (FDFT1), arylamine N-acetyltransferase (NAT-I), lipoprotein lipase (LPL), and an uncharacterized expressed sequence tag (D8S503). Southern blot analysis of 66 esophageal adenocarcinomas demonstrated only CTSB and FDFT1 were consistently amplified in eight (12.1%) of the tumors. Neither NAT-1 nor LPL were amplified. Northern blot analysis showed overexpression of CTSB and FDFT1 mRNA in all six of the amplified esophageal adenocarcinomas analyzed. CTSB mRNA overexpression also was present in two of six nonamplified tumors analyzed. However, FDFT1 mRNA overexpression without amplification was not observed. Western blot analysis confirmed CTSB protein overexpression in tumor specimens with CTSB mRNA overexpression compared with either normal controls or tumors without mRNA overexpression. Abundant extracellular expression of CTSB protein was found in 29 of 40 (72.5%) of esophageal adenocarcinoma specimens by using immunohistochemical analysis. The finding of an amplicon at 8p22-23 resulting in CTSB gene amplification and overexpression supports an important role for CTSB in esophageal adenocarcinoma and possibly in other tumors.