O-charoenrat Pornchai, Sarkaria Inderpal, Talbot Simon G, Reddy Pabbathi, Dao Su, Ngai Ivan, Shaha Ashok, Kraus Dennis, Shah Jatin, Rusch Valerie, Ramanathan Y, Singh Bhuvanesh
The Laboratory of Epithelial Cancer Biology, Memorial Sloan-Kettering Cancer Center, New York, New York 10065, USA.
Clin Cancer Res. 2008 Nov 1;14(21):6780-9. doi: 10.1158/1078-0432.CCR-08-0719.
Ectopic expression of squamous cell carcinoma-related oncogene (SCCRO or DCUN1D1) in NIH-3T3 cells induces invasion in vitro and produces highly invasive xenografts in nude mice with a propensity for regional lymphatical metastasis. The aim of this study was to identify the molecular mechanism underlying SCCRO-induced invasion and metastasis.
The molecular mechanism of SCCRO-mediated effects on matrix metalloproteinase-2 (MMP2) levels and activity were assessed using a combination of cell biological and molecular methods, including real-time PCR, reporter assay, RNA interference, and chromatin immunoprecipitation assay. Tumor specimens from primary upper aerodigestive tract carcinomas (n = 89) were examined for levels of SCCRO, MMP2, MMP9, MT1-MMP, TIMP1, and TIMP2 mRNA by real-time PCR.
Overexpression of SCCRO increases MMP2 levels and activity, which is required for SCCRO-induced invasion. Modified McKay assays reveal that SCCRO does not bind to the MMP2 promoter, suggesting that its transcriptional effects are indirect. Deletion or mutation of the activator protein-2 (AP2) and p53 binding element within the MMP2 promoter abrogates SCCRO-driven activation. Ectopic expression of SCCRO increases AP2 levels and promotes the binding of p53 to the MMP2 promoter. Consistent with these findings, SCCRO and MMP2 are coexpressed (P<0.0001; r(2)=0.58; 95% confidence interval, 0.46-0.69) in primary (upper aerodigestive tract) carcinomas (n=89), and this coexpression is associated with an increased prevalence of regional nodal metastasis (P=0.04; relative risk, 1.53).
SCCRO-induced invasion involves activation of MMP2 transcription in an AP2- and p53-dependent manner. SCCRO is a potential marker for metastatic progression in affected cancers.
鳞状细胞癌相关癌基因（SCCRO或DCUN1D1）在NIH-3T3细胞中的异位表达可在体外诱导侵袭，并在裸鼠中产生具有区域淋巴结转移倾向的高度侵袭性异种移植物。本研究的目的是确定SCCRO诱导侵袭和转移的分子机制。
采用细胞生物学和分子方法相结合的手段，包括实时PCR、报告基因检测、RNA干扰和染色质免疫沉淀检测，评估SCCRO介导的对基质金属蛋白酶-2（MMP2）水平和活性的影响机制。通过实时PCR检测89例原发性上消化道癌肿瘤标本中SCCRO、MMP2、MMP9、MT1-MMP、TIMP1和TIMP2 mRNA的水平。
SCCRO的过表达增加了MMP2的水平和活性，这是SCCRO诱导侵袭所必需的。改良的麦凯试验表明，SCCRO不与MMP2启动子结合，提示其转录作用是间接的。MMP2启动子内激活蛋白-2（AP2）和p53结合元件的缺失或突变可消除SCCRO驱动的激活作用。SCCRO的异位表达增加了AP2水平，并促进p53与MMP2启动子的结合。与这些发现一致，在89例原发性（上消化道）癌中，SCCRO和MMP2共表达（P<0.0001；r(2)=0.58；95%置信区间，0.46-0.69），这种共表达与区域淋巴结转移的发生率增加相关（P=0.04；相对风险，1.53）。
SCCRO诱导的侵袭涉及以AP2和p53依赖的方式激活MMP2转录。SCCRO是受影响癌症转移进展的潜在标志物。
