Fukuda Masakatsu, Hiroi Miki, Suzuki Seiji, Ohmori Yoshihiro, Sakashita Hideaki
Second Division of Oral and Maxillofacial Surgery, Department of Diagnostic and Therapeutic Sciences, Meikai University School of Dentistry, Saitama, Japan.
Oncol Rep. 2008 Jun;19(6):1421-7.
Molecular studies of cylindromas, which arise from the eccrine or apocrine cells of the skin, have demonstrated frequent alterations at chromosome 16q12-13, recently found to house the cylindromatosis (CYLD) gene. CYLD, a tumor suppressor gene, has deubiquitinating enzyme activity and inhibits the activation of transcription factor NF-kappaB. Loss of the deubiquitinating activity of CYLD is correlated with tumorigenesis. It has been reported that the expression of CYLD is observed in various organs. We demonstrated previously that human salivary gland tumor (SGT) cell line, HSG spontaneously expresses CYLD and also found that adenoid cystic carcinoma (ACC) arising from the hard palate was distinctly positive for CYLD, immunohistochemically. However, it is unclear whether loss of CYLD is associated with development of SGTs. This study examined CYLD function in SGT cells and attempted to clarify whether CYLD is associated with development of SGTs. The expression of CYLD and NF-kappaB mRNAs in HSG cells was increased by TNF-alpha. Translocation of NF-kappaB protein from the cytoplasm to the nucleus in HSG cells peaked at 30 min after TNF-alpha stimulation, then decreased at 60 min, whereas that of CYLD protein increased gradually in a time-dependent manner. Luciferase reporter assay indicated that TNF-alpha induced a 5-fold increase of NF-kappaB-dependent transcription at 4 h, which was further enhanced by knockdown of CYLD using RNA interference. Taken together, these data demonstrated that the levels of both CYLD and NF-kappaB mRNAs accumulated in HSG cells during 24 h after TNF-alpha stimulation, although the NF-kappaB activity in the cells was at least negatively regulated by CYLD. Immunohistochemical examinations revealed that there are several correlations between the expression of CYLD and NF-kappaB-related factors in 17 cases of ACC tissues. These findings suggest that loss of CYLD is associated with development of SGTs.
圆柱瘤起源于皮肤的小汗腺或大汗腺细胞，对其进行的分子研究表明，16号染色体q12 - 13区域频繁出现改变，该区域最近被发现含有圆柱瘤病（CYLD）基因。CYLD是一种肿瘤抑制基因，具有去泛素化酶活性，可抑制转录因子NF-κB的激活。CYLD去泛素化活性的丧失与肿瘤发生相关。据报道，CYLD在各种器官中均有表达。我们之前证明，人涎腺肿瘤（SGT）细胞系HSG可自发表达CYLD，还发现硬腭来源的腺样囊性癌（ACC）在免疫组织化学上CYLD呈明显阳性。然而，尚不清楚CYLD的缺失是否与SGT的发生有关。本研究检测了CYLD在SGT细胞中的功能，并试图阐明CYLD是否与SGT的发生有关。TNF-α可使HSG细胞中CYLD和NF-κB mRNA的表达增加。TNF-α刺激后，HSG细胞中NF-κB蛋白从细胞质向细胞核的转位在30分钟时达到峰值，然后在60分钟时下降，而CYLD蛋白则以时间依赖性方式逐渐增加。荧光素酶报告基因检测表明，TNF-α在4小时时可诱导NF-κB依赖性转录增加5倍，使用RNA干扰敲低CYLD可进一步增强这种增加。综上所述，这些数据表明，TNF-α刺激后24小时内，HSG细胞中CYLD和NF-κB mRNA的水平均有所积累，尽管细胞中的NF-κB活性至少受到CYLD的负调控。免疫组织化学检查显示，在17例ACC组织中，CYLD的表达与NF-κB相关因子之间存在多种相关性。这些发现表明，CYLD的缺失与SGT的发生有关。
