Department of Otolaryngology, Head and Neck Surgery, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany.
Oral Oncol. 2010 Sep;46(9):678-83. doi: 10.1016/j.oraloncology.2010.06.016. Epub 2010 Aug 21.
Promoter hypermethylation of tumor suppressor genes is a common feature of primary cancer cells. However, at date the somatic epigenetic events that occur in head and neck squamous cell carcinoma (HNSCC) tumorigenesis are not yet been well defined. In the present study we analysed the methylation status of the gene hypermethylated in cancer-1 (hic1), a gene located on chromosome 17p13.3, a region frequently lost in HNSCC. We analysed 22 HNSCC samples and three cell lines using methylation specific PCR (MSP). We found hic1 methylated in 21 out of 22 samples and in all three cell lines. Treatment of the cell lines with the demethylating agent 5-Azacytidin (5-Aza) resulted in the demethylation of the hic1 promoter and reactivation of hic1 expression as determined by MSP, qPCR and Western blot. Functional analyses revealed decreased proliferative activity and colony forming ability of treated cells. In summary, we found in HNSCC hic1 regulated by promoter methylation. 5-Aza application resulted in the reexpression of hic1 and was followed by decreased aggressiveness of the cancer cells. Our data indicate that hic1 might be a player in HNSCC development and suggest further evaluation of 5-Aza for HNSCC treatment.
抑癌基因启动子的异常甲基化是原发性癌细胞的一个常见特征。然而，目前为止，发生在头颈部鳞状细胞癌（HNSCC）肿瘤发生中的体细胞表观遗传事件尚不完全清楚。在本研究中，我们分析了位于 17p13.3 染色体上的基因 hypermethylated in cancer-1（hic1）的甲基化状态，该基因位于 HNSCC 中经常丢失的区域。我们使用甲基化特异性 PCR（MSP）分析了 22 个 HNSCC 样本和 3 个细胞系。我们发现 hic1 在 22 个样本中的 21 个和所有 3 个细胞系中均发生甲基化。用去甲基化剂 5-氮杂胞苷（5-Aza）处理细胞系后，通过 MSP、qPCR 和 Western blot 确定 hic1 启动子去甲基化和 hic1 表达重新激活。功能分析显示，处理后的细胞增殖活性和集落形成能力降低。总之，我们在 HNSCC 中发现 hic1 受启动子甲基化调控。5-Aza 的应用导致 hic1 的重新表达，并随后导致癌细胞侵袭性降低。我们的数据表明 hic1 可能是 HNSCC 发展的参与者，并提示进一步评估 5-Aza 用于 HNSCC 治疗。
