Diagnostic and therapeutic application of cell-cycle checkpoint genes for oral squamous cell cancer.

CHFR含有一个环状结构域，具有泛素连接酶活性，一个新的有丝分裂检查点基因推迟了微管毒素处理细胞中的染色体凝聚。CHFR通过启动子甲基化失活，而缺乏CHFR的癌细胞对微管抑制剂非常敏感。(1)与CHFR相互作用的蛋白质，即有丝分裂-检查点泛素连接酶。作为筛选的结果，我们分离了典型的和非典型的E2泛素结合酶作为CHFR相互作用的蛋白，它们分别参与蛋白水解性泛素化和非蛋白水解性泛素化。这增加了CHFR根据细胞情况切换规范泛素化和非规范泛素化的可能性。另一方面，我们分离了与CHFR的FHA结构域相互作用的Gadd34。此外，在pres…中，chfr部分地从胞核移动到细胞质。微管抑制剂多西紫杉醇的增加，使CHFR和Gadd34在胞浆内共存。这种共定位之后是细胞死亡。CHFR有丝分裂检查点蛋白抑制了核因子-kB的转录活性。为了阐明CHFR调控肿瘤生长的分子机制，我们的分析集中在CHFR介导的转录调控上。利用芯片分析，我们发现CHFR下调了NF-kB信号转导。NF-kB依赖的荧光素酶分析表明，CHFR的过表达抑制了NF-kB信号转导。此外，下调CHFR可激活核因子-kB的活性。此外，我们还发现作为核因子-kB靶基因之一的IL-8受CHFR的调控。CHFR过表达显著抑制IL-8的mRNA和蛋白水平。总之，我们的发现揭示了CHFR作为核因子-kB信号调节因子的新功能，这可能是CHFR抑制肿瘤的原因。较少

CHFR which contains a RING domain and has ubiquitin ligase activity, a novel mitotic checkpoint gene delays chromosome condensation in cells treated with microtubule poisons. CHFR is inactivated by promoter methylation, and cancer cells lacking CHFR are sensitive to microtubule inhibitors.(1) Proteins interacting with CHFR, mitotic-checkpoint ubiquitin ligase.In this study, we isolated cellular proteins capable of interacting with CHFR using yeast two-hybrid method to clarify the function of CHFR. As a result of the screening, we isolated canonical and noncanonical E2 ubiquitin conjugating enzymes as CHFR interacting proteins, which are involved in proteolytic and non-proteolytic ubiquitination respectively. This raises the possibility that CHFR is switching canonical and noncanonical ubiquitination depending on the situation of cells.On the other hand, we isolated gadd34 which interacted with the FHA domain of CHFR. Furthermore, CHFR moved in part from nucleus to cytoplasm in the pres … More ence of microtubule inhibitor docetaxel, which enabled colocalization of CHFR and gadd34 in cytoplasm. This colocalization was followed by cell death. These suggest that gadd34 and CHFR cooperate to mediate cell death in response to mitotic stress.(2) CHFR mitotic checkpoint protein inhibits the transcriptional activity of NF-kB.To clarify the molecular mechanisms by which CHFR modulates tumor growth, our analysis focused on transcriptional regulation mediated by CHFR. Using microarray analysis, we found that CHFR downregulated NF-kB signaling. NF-kB-dependent luciferase assay demonstrated that overexpression of CHFR inhibited NF-kB signaling. Moreover, knockdown of CHFR activated the NF-kB activity. Furthermore, we found that IL-8, one of the NF-kB target genes, was regulated by CHFR. mRNA and protein levels of IL-8 were significantly repressed by overexpression of CHFR. Altogether, our findings reveal a novel function of CHFR as a regulator of NF-kB signaling, and which might account for tumor suppression by CHFR. Less