Identification of cervical adeno carcinoma related tumor suppressor using proteomic method

人乳头瘤病毒（HPV）被认为在宫颈癌发生中起着因果作用。大约在95%的宫颈癌组织中，通过从癌组织中提取的翼DNA发现HPV感染。HPV 16型是最常从所有宫颈癌组织中鉴定的HPV类型，而HPV 18型是最常在宫颈腺癌中发现的HPV类型，其占宫颈癌的约10-20%。子宫颈腺癌是一种常见的恶性肿瘤，与鳞状细胞癌相比，它发生在年轻的女性身上，并且预后比鳞状细胞癌差。鉴于每种类型的HPV在相同年龄感染宫颈上皮，HPV 18型被认为比HPV 16型具有更强的转化能力。HPV有两个致癌基因，E6和E7。E7癌蛋白与抑癌基因pRb相互作用。虽然E6癌蛋白与肿瘤抑制因子p53相互作用，但它也通过泛素介导的途径降解p53，这取决于E6 AP的表达， ...更多信息 最大泛素蛋白连接酶。中川俊辅博士是这项研究的成员，他鉴定了一种新的肿瘤抑制蛋白人类涂鸦。人类Scribble是果蝇肿瘤抑制蛋白的人类同源物，其在控制细胞顶-基底侧极性中起作用。scribble突变的缺失导致上皮极性的破坏和上皮细胞的过度生长。Hunan Scribble与果蝇同源物具有几乎相同的蛋白质结构。人Scribble在果蝇scribble突变体中的表达恢复了细胞极性丧失和上皮细胞过度生长的表型。这些结果表明，人Scribble具有抑制肿瘤发生的作用。我们试图鉴定一种新的与宫颈腺癌发生相关的抑癌蛋白。我们鉴定了dbc-1（deleted in breast cancer-1）基因的产物，该基因定位于8 p21，并且在乳腺癌中经常缺失，作为现在泛素介导的E6癌蛋白降解靶点。DBC 1具有亮氨酸拉链结构域、E6结合共有基序和Ca结合EF-手基序。DBC-1与低风险型E6（11型）和高风险型E6（16型和18型）结合，但与低风险型11 E6的结合弱于与高风险型16和18 E6的结合。我们还发现，E6癌蛋白降解DBC-1的存在下，E6 AP。DBC-1定位于细胞核，但在凋亡过程中集中于线粒体，提示E6-E6 AP降解DBC-1可能对线粒体凋亡信号通路产生影响，从而参与宫颈癌的发生。

Human papillomavirus(HPV) is thought to have a causal role in cervical carcinogenesis. Approximately, in 95% of cervical cancer tissues, infection of HPV in found by wing DNA extracted from cancer tissues. HPV type 16 is the type of HPV most frequently identified from allover cervical cancer tissues, while HPV type 18 is the HPV type most frequently found in cervical adeno carcinoma, which represent about 10-20% of cervical cancer. Cervical adenocarcinoma is known to occur in younger women comparing with squamous cell carcinoma and to have poorer prognosis than squamous cell carcinoma. Given that each types of HPV infect to the cervical epithelia at the same age, HPV type 18 is thought to have stronger transforming ability than HPV type 16. HPV has two oncogenes, E6 and E7. E7 oncoprotein interacts with tumor suppressor pRb. While E6 oncoprotein interacts with tumor suppresser p53, it also degrade p53 through the ubiquitin-mediated pathway depending on the expression of E6AP, the cellu … More lar ubiquitin-protein ligase. Dr.Shunsuke Nakagawa, who is a member of this research, identified a new tumor suppressor protein human Scribble. Human Scribble is a human homologue of Drosophila tumor suppressor protein, which has a role in control of cellular apical-basolateral polarity. Loss of scribble mutation leads to the disruption of epithelial polarity and overgrowth of epithelia. Hunan Scribble has almost equivalent protein structure to its Drosophila homologue. The expression of human Scribble in Drosophila scribble mutant recovers phenotype of loss of cellular polarity and overgrowth of epithelia. These results indicate that human Scribble has a role in suppression of tumorgenesis. We tried to identify a new tumor suppressor protein related to the development of cervical adenocarcinoma. We identified the product of dbc-1(deleted in breast cancer-1) gene, which localizes on 8p21 and is frequently deleted among breast cancers, as a now ubiqituin-mediated degradation target of E6 oncoprotein. DBC1 possesses a Leucine Zipper domain, E6 binding consensus motif and a Ca binding EF-hand motif. DBC-1 bound with both low risk type E6, type 11, and with high risk E6s, type 16 and 18, but the binding with low risk 11E6 was weaker than with high risk 16 and 18E6. We also revealed that E6 oncoprotein degrades DBC-1 in the presence of E6AP. DBC-1 localized in nucleus, but concentrated on mitochondria during apoptosis.Our data suggest the possibility that degradation of DBC-1 by E6-E6AP might have some effect on the apoptotic signal pathway in mitochondria, which takes part in the cervical carcinogenesis Less