1. 5-Aza-2′-deoxycytidine suppresses human renal carcinoma cell growth in a xenograft model via up-regulation of the connexin 32 gene
- Author
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Hagiwara, H, Sato, H, Ohde, Y, Takano, Y, Seki, T, Ariga, T, Hokaiwado, N, Asamoto, M, Shirai, T, Nagashima, Y, and Yano, T
- Subjects
Antimetabolites, Antineoplastic ,Reverse Transcriptase Polymerase Chain Reaction ,Mice, Nude ,Decitabine ,Research Papers ,Xenograft Model Antitumor Assays ,Connexins ,Up-Regulation ,Mice ,Cell Line, Tumor ,Azacitidine ,Animals ,Humans ,Female ,RNA, Messenger ,RNA, Small Interfering ,Carcinoma, Renal Cell - Abstract
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.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.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.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.
- Published
- 2008