RUNX3 Inactivation by Point Mutations and Aberrant DNA Methylation in Bladder Tumors

Abstract

RUNX3 is inactivated at high frequency in many tumors. However, in most cases, inactivation is caused by silencing of the gene due to promoter hypermethylation. Because epigenetic silencing is known to affect many major tumor suppressor genes in cancer cells, it is not clear whether RUNX3 is primarily responsible for the induction of carcinogenesis in these cases, except for the gastric cancer cases that we reported previously. We investigated genetic and epigenetic alterations of RUNX3 in 124 bladder tumor cases and seven bladder tumor-derived cell lines. Here we show that RUNX3 is inactivated by aberrant DNA methylation in 73% (90 of 124) of primary bladder tumor specimens and 86% (six of seven) of bladder tumor cell lines. In contrast, the promoter regions of 20 normal bladder mucosae were unmethylated. Importantly, one patient bore missense mutations, each of which resulted in amino acid substitutions in the highly conserved Runt domain. The mutations abolished the DNA-binding ability of RUNX3. A second patient had a single nucleotide deletion within the Runt domain coding region that resulted in truncation of the protein. RUNX3 methylation was a significant risk factor for bladder tumor development, superficial bladder tumor recurrence, and subsequent tumor progression. These results strongly suggest that inactivation of RUNX3 may contribute to bladder tumor development and that promoter methylation and silencing of RUNX3 could be useful prognostic markers for both bladder tumor recurrence and progression. (Cancer Res 2005; 65(20): 9347-54)

RUNX3 is multifunctional in carcinogenesis of multiple solid tumors

“…Diverse tumor tissues have been reported to exhibit RUNX3 hypermethylation and inactivation. These include tissues and cell lines that originated from gastric (Li et al, 2002;Oshimo et al, 2004), bladder (Kim et al, 2005;Wolff et al, 2008), colorectal (Ahlquist et al, 2008;Soong et al, 2009;Subramaniam et al, 2009), breast (Lau et al, 2006;Jiang et al, 2008), lung (Sato et al, 2006), pancreatic (Wada et al, 2004), brain cancers (Mueller et al, 2007), and hepatocellular carcinoma . Notably, RUNX3 methylation status is one of the five markers used to classify colorectal tumors associated with very high frequencies of CpG island methylation (CIMP), microsatellite instability, and BRAF mutation (Weisenberger et al, 2006).…”

“…Notably, RUNX3 methylation status is one of the five markers used to classify colorectal tumors associated with very high frequencies of CpG island methylation (CIMP), microsatellite instability, and BRAF mutation (Weisenberger et al, 2006). Moreover, hypermethylation of RUNX3 is associated with a 100-fold increase risk of developing bladder cancer (Kim et al, 2005). RUNX3 methylation is not only acquired early during tumorigenesis, but also increases with age: RUNX3 is thus an attractive candidate for cancer detection and prognosis (Wolff et al, 2008).…”

MicroRNA-148a Can Regulate Runt-Related Transcription Factor 3 Gene Expression via Modulation of DNA Methyltransferase 1 in Gastric Cancer

“…The genesis and progression of human gastric cancer is thought to be crucially influenced by genetic and epigenetic alterations, including the activation of oncogenes and the inactivation of tumor suppressor genes (Wu et al, 2012). Runt-related transcription factor 3 (RUNX3), a member of the family of transcription factors that contain the runt domain, is located at human chromosome 1p36 and has been identified as a tumor suppressor in gastric cancer (Li et al, 2002) as well as breast , bladder (Kim et al, 2005), and lung (Araki et al, 2005) cancers. A loss or substantial decrease in RUNX3 expression may be causally related to gastric cancer, as it correlates with differentiation, lymph node metastasis, and poor prognosis of this disease (Hsu et al, 2009).…”

Identification of DNA hypermethylation of SOX9 in association with bladder cancer progression using CpG microarrays

“…Hypermethylation of CpG islands is frequently associated with inappropriate transcriptional silencing of critical genes including tumour suppressors (Costello et al, 2000;Esteller et al, 2001;Esteller, 2002;Jones and Baylin, 2002;Feinberg et al, 2006). Transcriptional inactivation by CpG island promoter hypermethylation is a well-established mechanism for gene silencing in bladder cancer (Cordon-Cardo et al, 2000;Muto et al, 2000;Lee et al, 2001;Markl et al, 2001;Stoehr et al, 2004;Catto et al, 2005;Chapman et al, 2005;Kim et al, 2005;Marsit et al, 2005;Wolff et al, 2005;Urakami et al, 2006). Genes reported to be epigenetically inactivated by hypermethylation in bladder cancer include p16 INK4a , CDKN2A, RUNX3 or RASSF1, among others (Cordon-Cardo et al, 2000;Muto et al, 2000;Lee et al, 2001;Markl et al, 2001;Stoehr et al, 2004;Catto et al, 2005;Chapman et al, 2005;Kim et al, 2005;Marsit et al, 2005;Wolff et al, 2005;Urakami et al, 2006).…”