5-Aza-2′-deoxycytidine suppresses human renal carcinoma cell growth in a xenograft model via up-regulation of the connexin 32 gene
5-Aza-2′-deoxycytidine suppresses human renal carcinoma cell growth in a xenograft model via up-regulation of the connexin 32 gene
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DOI：
10.1038/bjp.2008.17
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发表时间：
2008-04-01
影响因子：
7.3
通讯作者：
Yano, T.
中科院分区：
文献类型：
--
作者：
Hagiwara, H.;Sato, H.;Yano, T.
背景与目的：连接蛋白（connexin，Cx）32基因是差距连接基因家族的一员，在人肾细胞癌（renal cell carcinoma，RCC）中起抑癌基因的作用，其启动子区CpG岛的高甲基化使Cx 32基因表达下调。目前的研究调查了通过DNA去甲基化剂恢复肾细胞癌中因高甲基化而沉默的Cx 32是否是一种有效的治疗肾细胞癌的方法。实验方法：应用RT-PCR、肿瘤重量和体积测定等方法，观察了DNA去甲基化酶抑制剂5-aza-CdR对Caki-1细胞株Cx 32 mRNA表达和肿瘤生长的影响。Cx 32短干扰（si）RNA抑制Caki-1肿瘤中Cx 32的表达，并评价siRNA对5-aza-CdR依赖性抑制裸鼠肿瘤生长的作用。关键结果：5-aza-CdR处理抑制了裸鼠Caki-1细胞的生长70%，并使Cx 32 mRNA水平增加了7倍。瘤内注射Cx 32 siRNA几乎完全抑制了Cx 32 mRNA的表达，并显着降低了5-aza-CdR治疗的裸鼠肿瘤生长的抑制。结论和影响：5-氮杂-CdR抑制Caki-1肿瘤的生长在异种移植模型中，通过恢复Cx 32的表达。这一发现表明，5-aza-CdR治疗可能是一种新的有效的治疗人类转移性RCC和Cx 32可能是一个潜在的目标，为RCC的治疗。
Background and purpose: The connexin ( Cx) 32 gene, a member of the gap junction gene family, acts as a tumour suppressor gene in human renal cell carcinoma ( RCC) and is down-regulated by the hypermethylation of CpG islands in a promoter region of the Cx gene. The current study investigated whether the restoration of Cx32 silenced by hypermethylation in RCC by a DNA demethylating agent could be an effective treatment against RCC. Experimental approach: Using nude mice bearing Caki-1 cells ( a human metastatic RCC cell line), the effects of 5-aza-2'-deoxycytidine ( 5-aza-CdR), a DNA demethylase inhibitor, on Cx32 mRNA expression and tumour growth were examined by RT-PCR, and by measuring tumour weight and volume. Cx32 expression in Caki-1 tumours was inhibited by Cx32 short interfering ( si) RNA, and the effect of siRNA on 5-aza-CdR-dependent suppression of tumour growth in nude mice was evaluated. Key results: 5-aza-CdR treatment inhibited the growth of Caki-1 cells in nude mice by 70% and increased 7-fold the level of Cx32 mRNA. The intratumour injection of Cx32 siRNA almost totally inhibited the expression of Cx32 mRNA and significantly reduced the suppression of tumour growth in 5-aza-CdR-treated nude mice. Conclusions and implications: 5-aza-CdR suppressed the growth of Caki-1 tumours in a xenograft model, by restoring Cx32 expression. This finding suggests that treatment with 5-aza-CdR could be a new effective therapy against human metastatic RCC and that Cx32 could be a potential target for the treatment of RCC.