Isolation and sequencing of a novel tropomyosin isoform preferentially associated with colon cancer
Isolation and sequencing of a novel tropomyosin isoform preferentially associated with colon cancer
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DOI：
10.1053/gast.2002.34154
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发表时间：
2002-07-01
期刊：
影响因子：
29.4
通讯作者：
Lin, JJC
中科院分区：
文献类型：
--
作者：
Lin, JLC;Geng, X;Lin, JJC
背景与目的：非肌肉人原肌球蛋白 (hTM) 亚型具有独特的功能，可能在各种疾病过程中发挥重要作用。方法：为了鉴定结肠上皮原肌球蛋白同种型，通过与所有已知 hTM 同种型的信息互补的寡核苷酸探针筛选从人结肠癌细胞系 T84 制备的互补 DNA 文库。获得了一个名为 TC22 的新克隆。除了 C 末端结构域（编码外显子 9 的氨基酸 222-247）外，TC22 亚型的氨基酸序列与亚型 5 (hTM5) 相同。 结果：Northern 印迹分析显示 TC22 信息在转化的上皮细胞系和肿瘤组织中表达，但在正常上皮细胞中不表达。我们开发了一种针对 TC22 异构体 (TC22-4) 的单克隆抗体。通过蛋白质印迹和免疫过氧化物酶测定，我们分析了来自 96 名患有结肠息肉（增生）或腺瘤（伴有或不伴有不典型增生和癌症）的患者的 105 份结肠标本（新鲜冷冻和福尔马林固定）。 22 份结肠癌标本中的 21 份 (95%) 显示出 TC22 的存在，而 17 份正常结肠标本中只有 1 份显示存在 TC22，并且 :13 增生性息肉标本中均没有 (P < 0.000:1)。通过免疫过氧化物酶染色检测，TC22 表达在良性腺瘤性息肉 (35%) 和轻度和重度不典型增生息肉 (分别为 57% 和 100%) 中逐渐增加。结论：我们克隆并测序了一种新的 hTM 亚型 TC22，它与结肠肿瘤和癌症密切相关。 TC22 可能为结肠癌的监测提供有用的生物标志物。
Background & Aims: Nonmuscle human tropomyosin (hTM) isoforms have distinct functions and may play important roles in various disease processes. Methods: In an attempt to identify colon epithelial tropomyosin isoform, a complementary DNA library prepared from a human colon cancer cell line T84 was screened by an oligonucleotide probe complementary to messages of all known hTM isoforms. A novel clone called TC22 was obtained. The amino acid sequence of TC22 isoform is identical to isoform 5 (hTM5) apart from the C terminal domain, amino acids 222-247 coding the exon 9. Results: Northern blot analysis showed that TC22 message is expressed in transformed epithelial cell lines and tumor tissues but not in normal epithelial cells. We developed a monoclonal antibody specific to TC22 isoform (TC22-4). By Western blot and immunoperoxidase assays, we analyzed 105 colonic specimens (fresh frozen and formalin fixed) from 96 patients with colon polyps (hyperplastic) or adenomas with or without dysplasia and cancer. Twenty-one of 22 (95%) of colon cancer specimens showed the presence of TC22, compared with only 1 of the 17 normal colon specimens and none of the :13 hyperplastic polyps (P < 0.000:1). As assayed by immunoperoxidase staining, TC22 expression progressively increased in benign adenomatous polyps (35%) and polyps with mild and severe dysplasia (57% and 100%, respectively). Conclusions: We cloned and sequenced a novel hTM isoform, TC22, which is strongly associated with colonic neoplasia and carcinoma. TC22 may provide a useful biomarker for surveillance of colon cancer.