The APC tumor suppressor controls entry into S-phase through its ability to regulate the cyclin D/RB pathway
The APC tumor suppressor controls entry into S-phase through its ability to regulate the cyclin D/RB pathway
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DOI：
10.1053/gast.2002.35382
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发表时间：
2002-09-01
期刊：
影响因子：
29.4
通讯作者：
Groden, J
中科院分区：
文献类型：
--
作者：
Heinen, CD;Goss, KH;Groden, J
背景与目的：APC基因突变是大多数结直肠肿瘤的早期改变。在试图确定其在肿瘤发展中的作用时，我们询问是否将野生型APC重新引入具有突变APC的结直肠癌细胞中影响细胞周期进程。研究方法：利用瞬时转染法，将含有APC互补DNA和编码绿色荧光蛋白的DNA的质粒在SW 480细胞中表达。此外，还将其他几种构建体与APC共表达，以确定它们的综合效应。结果如下：我们报道了用野生型APC转染的结直肠癌细胞系阻滞在细胞周期的G（1）期，并且这种阻滞通过将组成型活性β-连环蛋白或细胞周期蛋白D1和cMYC一起共转染而被废除。APC诱导的细胞周期停滞涉及β-连环蛋白介导的转录的破坏，并依赖于G（1）/S调节机制的组分，因为E1 a或E2 F-1、-2或-3的过表达超越了G（1）停滞。与此一致，APC转染抑制RB磷酸化并降低细胞周期蛋白D1的水平。结论：我们的研究结果表明，APC在G（1）/S调节通路中RB的上游发挥作用，细胞周期蛋白D1和cMYC影响APC介导的阻滞等同于致癌β-连环蛋白，大多数结肠肿瘤通过APC突变破坏G（1）/S进展的控制。
Background & Aims: APC gene mutation is an early alteration in most colorectal tumors. In an attempt to determine its role in tumor development, we asked whether reintroducing wild-type APC into colorectal cancer cells with mutant APC affected cell cycle progression. Methods: Using transient transfection, a plasmid containing the APC complementary DNA and DNA encoding the green fluorescent protein was expressed in SW480 cells. In addition, several other constructs were co-expressed with APC to determine their combined effects. Results: We report that colorectal cancer cell lines transfected with wild-type APC arrest in the G(1)-phase of the cell cycle and that this arrest is abrogated by cotransfecting constitutively active beta-catenin or cyclin D1 and cMYC together. This APC-induced cell cycle arrest involves the disruption of beta-catenin-mediated transcription and depends on components of the G(1)/S regulatory machinery, as overexpression of E1a or E2F-1, -2, or -3 overrides the G(1) arrest. Consistent with this, APC transfection inhibits RB phosphorylation and reduces levels of cyclin D1. Conclusions: Our results suggest that APC functions upstream of RB in the G(1)/S regulatory pathway, cyclin D1 and cMYC affect APC-mediated arrest equivalently to oncogenic beta-catenin, and most colon tumors disrupt control of G(1)/S progression by APC mutation.