Spleen tyrosine kinase as a novel candidate tumor suppressor gene for human oral squamous cell carcinoma
Spleen tyrosine kinase as a novel candidate tumor suppressor gene for human oral squamous cell carcinoma
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DOI：
10.1002/ijc.24237
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发表时间：
2009-06-01
影响因子：
6.4
通讯作者：
Shibahara, Takahiko
中科院分区：
文献类型：
--
作者：
Ogane, Satoru;Oncla, Takeshi;Shibahara, Takahiko
我们分析了原发性口腔鳞状细胞癌（OSCC）和OSCC衍生细胞系中脾酪氨酸激酶（Syk）基因的突变和甲基化状态以及mRNA和蛋白水平，并在体外检测了Syk基因在OSCC衍生细胞系中的功能。使用定量实时逆转录聚合酶链反应，蛋白质印迹和免疫荧光7 OSCC衍生的细胞系和正常的口腔角质形成细胞（NOKs），Syk mRNA和蛋白质的表达通常下调，在所有的细胞系相比，NOKs。虽然在这些细胞系中没有发现Syk基因编码区的序列变异，但我们发现CpG岛区域频繁发生超甲基化。Syk表达通过实验性去甲基化恢复。此外，使用伤口愈合测定和体外侵袭测定，我们使用转染到OSCC衍生的细胞系中的Syk进行功能分析，并且它们显示出运动性和侵袭性的显著抑制。在临床样本中，通过免疫组织化学检测到高频率的Syk下调（33/53 [62%]）。此外，Syk表达状态与肿瘤转移至颈淋巴结显著相关（p = 0.047）。这些结果表明，Syk基因在口腔癌发生过程中经常失活，表观遗传机制可能调节表达的丧失，可能导致转移。(C)2008 Wiley-Liss，Inc.
We analyzed the mutational and methylation status of the spleen tyrosine kinase (Syk) gene and both mRNA and protein levels in primary oral squamous cell carcinoma (OSCC) and OSCC-derived cell lines and examined the function of the Syk gene in OSCC-derived cell lines in vitro. Using quantitative real-time reverse transcription polymerase chain reaction, Western blotting and immunofluorescence on 7 OSCC-derived cell lines and normal oral keratinocytes (NOKs), Syk mRNA and protein expression were commonly downregulated in all cell lines compared to the NOKs. Although no sequence variation in the coding region of the Syk gene was identified in these cell lines, we found frequent hypermethylation in the CpG island region. Syk expression was restored by experimental demethylation. In addition, using a wound healing assay and in vitro invasion assay, we performed functional analysis using Syk transfected into the OSCC-derived cell lines, and they showed significant inhibition of motility and invasiveness. In clinical samples, high frequencies of Syk downregulation were detected by immunohistochemistry (33 of 53 [62%]). Furthermore, the Syk expression status was correlated significantly (p = 0.047) with tumor metastasis to cervical lymph nodes. These results suggest that the Syk gene is frequently inactivated during oral carcinogenesis and that an epigenetic mechanism may regulate loss of expression possibly leading to metastasis. (C) 2008 Wiley-Liss, Inc.