• Functional epigenomics approach to identify methylated candidate tumour suppressor genes in renal cell carcinoma.

      Morris, M R; Gentle, D; Abdulrahman, M; Clarke, Noel W; Brown, Michael D; Kishida, Takeshi; Yao, M; Teh, B T; Latif, Farida; Maher, Eamonn R; et al. (2008-01-29)
      Promoter region hypermethylation and transcriptional silencing is a frequent cause of tumour suppressor gene (TSG) inactivation in many human cancers. Previously, to identify candidate epigenetically inactivated TSGs in renal cell carcinoma (RCC), we monitored changes in gene expression in four RCC cell lines after treatment with the demethylating agent 5-azacytidine. This enabled us to identify HAI-2/SPINT2 as a novel epigenetically inactivated candidate RCC TSG. To identify further candidate TSGs, we undertook bioinformatic and molecular genetic evaluation of a further 60 genes differentially expressed after demethylation. In addition to HAI-2/SPINT2, four genes (PLAU, CDH1, IGFB3 and MT1G) had previously been shown to undergo promoter methylation in RCC. After bioinformatic prioritisation, expression and/or methylation analysis of RCC cell lines+/-primary tumours was performed for 34 genes. KRT19 and CXCL16 were methylated in RCC cell lines and primary RCC; however, 22 genes were differentially expressed after demethylation but did not show primary tumour-specific methylation (methylated in normal tissue (n=1); methylated only in RCC cell lines (n=9) and not methylated in RCC cell lines (n=12)). Re-expression of CXCL16 reduced growth of an RCC cell line in vitro. In a summary, a functional epigenomic analysis of four RCC cell lines using microarrays representing 11 000 human genes yielded both known and novel candidate TSGs epigenetically inactivated in RCC, suggesting that this is valid strategy for the identification of novel TSGs and biomarkers.
    • Genome-wide methylation analysis identifies epigenetically inactivated candidate tumour suppressor genes in renal cell carcinoma.

      Morris, M R; Ricketts, C J; Gentle, D; McRonald, F; Carli, N; Khalili, H; Brown, Michael D; Kishida, T; Yao, M; Banks, R E; et al. (2011-03-24)
      The detection of promoter region hypermethylation and transcriptional silencing has facilitated the identification of candidate renal cell carcinoma (RCC) tumour suppressor genes (TSGs). We have used a genome-wide strategy (methylated DNA immunoprecipitation (MeDIP) and whole-genome array analysis in combination with high-density expression array analysis) to identify genes that are frequently methylated and silenced in RCC. MeDIP analysis on 9 RCC tumours and 3 non-malignant normal kidney tissue samples was performed, and an initial shortlist of 56 candidate genes that were methylated by array analysis was further investigated; 9 genes were confirmed to show frequent promoter region methylation in primary RCC tumour samples (KLHL35 (39%), QPCT (19%), SCUBE3 (19%), ZSCAN18 (32%), CCDC8 (35%), FBN2 (34%), ATP5G2 (36%), PCDH8 (58%) and CORO6 (22%)). RNAi knockdown for KLHL35, QPCT, SCUBE3, ZSCAN18, CCDC8 and FBN2 resulted in an anchorage-independent growth advantage. Tumour methylation of SCUBE3 was associated with a significantly increased risk of cancer death or relapse (P=0.0046). The identification of candidate epigenetically inactivated RCC TSGs provides new insights into renal tumourigenesis.