Li Chien-Feng, Huang Hsuan-Ying, Wu Wen-Ren, Liang Shih-Shin, Chen Yi-Ling, Chen Lih-Ren, Peng Yu-Ting, Lee Hui-Chieh, Shiue Yow-Ling
Department of Pathology, Chi Mei Medical Center, Tainan, Taiwan.
Ann Surg Oncol. 2014 Dec;21 Suppl 4:S711-20. doi: 10.1245/s10434-014-3825-0. Epub 2014 Jun 3.
Attenuated endogenous protein levels of cyclin-dependent kinase 2 associated protein 1 (p12(CDK2AP1)) and its active homodimer p25(CDK2AP1) were found in myxofibrosarcoma-derived cell lines. Clinical and biological significances of this putative tumor suppressor in myxofibrosarcoma were studied.
Plasmids carrying the CDK2AP1 gene and small hairpin RNA interference (shRNAi) targeting CDK2AP1 were transfected into NMFH-1 and/or OH931 cells to evaluate the effects on the CDK2, active caspase 3 (CASP3), cleaved-CASP8 and -CASP9 levels, cell cycle regulation, and/or apoptotic responses. Immunostaining of p12(CDK2AP1) was interpretable in 102 primary myxofibrosarcomas and correlated with clinicopathological variables, CDK2, Ki-67 and active CASP3 protein levels, and disease-specific survival.
Exogenous expression of p12(CDK2AP1) in NMFH-1 and OH931 cells significantly induced G0/G1 cell cycle arrest and down-regulated CDK2 protein level. In NMFH-1 cells, these aspects were reversed by shRNAi targeting CDK2AP1 gene. Increased active CASP3 and cleaved-CASP9, but not -CASP8, were detected after CDK2AP1 overexpression, suggesting the cellular apoptosis were induced through the mitochondrial pathway. Immunostains of p12(CDK2AP1) were aberrantly decreased in 56.9 % of cases; positively and negatively correlated with protein levels of CDK2 (p = 0.023), Ki-67 (p = 0.001) and active CASP3 (p < 0.001), respectively. Following by high histological grades, p12(CDK2AP1) down-regulation was predictive of worse disease-specific survival in univariate (p = 0.003) and multivariate (p = 0.004) analyses.
Through down-regulation of CDK2, high p12(CDK2AP1) level induced cell cycle arrest and the mitochondrial-dependent apoptotic pathway. Low p12(CDK2AP1) level represents a poor prognostic factor in patients with myxofibrosarcoma.
在黏液纤维肉瘤来源的细胞系中发现细胞周期蛋白依赖性激酶2相关蛋白1（p12(CDK2AP1)）及其活性同源二聚体p25(CDK2AP1)的内源性蛋白水平降低。研究了这种假定的肿瘤抑制因子在黏液纤维肉瘤中的临床和生物学意义。
将携带CDK2AP1基因的质粒和靶向CDK2AP1的小发夹RNA干扰（shRNAi）转染到NMFH-1和/或OH931细胞中，以评估对CDK2、活性半胱天冬酶3（CASP3）、裂解的CASP8和-CASP9水平、细胞周期调控和/或凋亡反应的影响。p12(CDK2AP1)的免疫染色在102例原发性黏液纤维肉瘤中可解释，并与临床病理变量、CDK2、Ki-67和活性CASP3蛋白水平以及疾病特异性生存率相关。
在NMFH-1和OH931细胞中外源性表达p12(CDK2AP1)显著诱导G0/G1细胞周期停滞并下调CDK2蛋白水平。在NMFH-1细胞中，靶向CDK2AP1基因的shRNAi逆转了这些方面。CDK2AP1过表达后检测到活性CASP3和裂解的CASP9增加，但未检测到-CASP8增加，表明细胞凋亡是通过线粒体途径诱导的。56.9%的病例中p12(CDK2AP1)的免疫染色异常降低；分别与CDK2（p = 0.023）、Ki-67（p = 0.001）和活性CASP3（p < 0.001）的蛋白水平呈正相关和负相关。在高组织学分级之后，p12(CDK2AP1)下调在单因素（p = 0.003）和多因素（p = 0.004）分析中预测疾病特异性生存率较差。
通过下调CDK2，高p12(CDK2AP1)水平诱导细胞周期停滞和线粒体依赖性凋亡途径。低p12(CDK2AP1)水平是黏液纤维肉瘤患者预后不良的一个因素。
