Asian Pacific Journal of Cancer Prevention

Asian Pacific Journal of Cancer Prevention (아시아태평양암예방학회)
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Hypermethylation and Clinicopathological Significance of RASAL1 Gene in Gastric Cancer

  • Chen, Hong (Department of Gastroenterology, Affiliated Zhongda Hospital, Southeast University) ;
  • Pan, Ying (Department of Gastroenterology, Affiliated Zhongda Hospital, Southeast University) ;
  • Cheng, Zheng-Yuan (Department of Gastroenterology, Affiliated Zhongda Hospital, Southeast University) ;
  • Wang, Zhi (Department of Gastroenterology, Affiliated Zhongda Hospital, Southeast University) ;
  • Liu, Yang (Department of Gastroenterology, Affiliated Zhongda Hospital, Southeast University) ;
  • Zhao, Zhu-Jiang (Key Laboratory of Developmental Genes and Human Diseases, Ministry of Education, Department of Genetics and Developmental Biology, Medical School of Southeast University) ;
  • Fan, Hong (Key Laboratory of Developmental Genes and Human Diseases, Ministry of Education, Department of Genetics and Developmental Biology, Medical School of Southeast University)
  • Published : 2013.11.30
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Abstract

Background: Recent studies have suggested that expression of the RAS protein activator like-1 gene (RASAL1) is decreased in gastric carcinoma tissues and cell lines, indicated a role in tumorigenesis and development of gastric cancer. Reduced expression of RASAL1 could result in aberrant increase of activity of RAS signaling pathways in cancer cells. However, the exact mechanism which induces down-regulation of the RASAL1 gene remains unclear. This study aimed to determine the methylation status and regulation of RASAL1 in gastric cancer. Materials and Methods: Using the methylation-specific polymerase chain reaction (MSP), the methylation status of CpG islands in the RASAL1 promoter in gastric cancers and paired adjacent non-cancerous tissues from 40 patients was assessed and its clinicopathological significance was analyzed. The methylation status of RASAL1 in gastric cancer lines MKN-28, SGC-790l, BGC-823, as well as in normal gastric epithelial cell line GES-l was also determined after treatment with a DNA methyltransferase inhibitor, 5-aza-2'-doexycytidine (5-Aza-CdR). RAS activity (GAS-GTP) was assessed through a pull-down method, while protein levels of ERK1/2, a downstream molecule of RAS signaling pathways, were determined by Western blotting. Results: The frequencies of RASAL1 promoter methylation in gastric cancer and paired adjacent non-cancerous tissues were 70% (28/40) and 30% (12/40) respectively (P<0.05). There were significantly correlations between RASAL1 promoter methylation with tumor differentiation, tumor size, invasive depth and lymph node metastasis in patients with gastric cancer (all P<0.05), but no correlation was found for age or gender. Promoter hypermethylation of the RASAL1 gene was detected in MKN-28, SGC-790l and BGC-823 cancer cells, but not in the normal gastric epithelial cell line GES-1. Elevated expression of the RASAL1 protein, a decreased RAS-GTP and p-ERK1/2 protein were detected in three gastric cancer cell lines after treatment with 5-Aza-CdR. Conclusions: Aberrant hypermethylation of the RASAL1 gene promoter frequently occurs in gastric cancer tissues and cells. In addition, the demethylating agent 5-Aza-CdR can reverse the hypermethylation of RASAL1 gene and up-regulate the expression of RASAL1 significantly in gastric cancer cells in vivo. Our study suggests that RASAL1 promoter methylation may have a certain relationship with the reduced RASAL1 expression in gastric cancer.

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References

  1. Bernards A, Settleman J (2009). Loss of the Ras Regulator RASAL1: Another Route to Ras Activation in Colorectal Cancer. Gastroenterology, 136, 46-8. https://doi.org/10.1053/j.gastro.2008.11.024
  2. Calvisi DF, Ladu S, Conner EA, et al (2011). Inactivation of Ras GTPase-activating proteins promotes unrestrained activity of wild-type Ras in human liver cancer. J Hepatol, 54, 311-9. https://doi.org/10.1016/j.jhep.2010.06.036
  3. Chen H, Yang XW, Zhang H, et al (2012). In vivo and in vitro expression of the RASAL1 gene in human gastric adenocarcinoma and its clinicopathological significance. Oncol Lett, 3, 535-40. https://doi.org/10.3892/ol.2011.513
  4. Gyorffy B, Schafer R (2010). Biomarkers downstream of RAS: a search for robust transcriptional targets. Curr Cancer Drug Targets, 10, 858-68. https://doi.org/10.2174/156800910793357916
  5. Jin H, Wang X, Ying J, et al (2007). Epigenetic silencing of a Ca(2+)-regulated RAS GTPase-activating protein RASAL defines a new mechanism of RAS activation in human cancers. Proc Natl Acad Sci USA, 104, 12353-8. https://doi.org/10.1073/pnas.0700153104
  6. Kolfschoten IG, van Leeuwen B, Berns K, et al (2005). A genetic screen identifies PITX1 as a suppressor of RAS activity and tumorigenicity. Cell, 121, 849-58. https://doi.org/10.1016/j.cell.2005.04.017
  7. Liu Q, Walker SA, Gao D, et al (2005). CAPRI and RASAL impose different modes of information processing on RAS due to contrasting temporal filtering of $Ca^{2+}$. J Cell Biol, 170, 183-90. https://doi.org/10.1083/jcb.200504167
  8. Ohta M, Seto M, Ijichi H, et al (2009). Decreased expression of the RAS GTPase activating protein RASAL1 is associated with colorectal tumor progression. Gastroenterology, 136, 206-16. https://doi.org/10.1053/j.gastro.2008.09.063
  9. Pino MS, Chung DC (2010). The chromosomal instability pathway in colon cancer. Gastroenterology, 138, 2059-72. https://doi.org/10.1053/j.gastro.2009.12.065
  10. Qiao F, Su X, Qiu X, et al (2012). Enforced expression of RASAL1 suppresses cell proliferation and the transformation ability of gastric cancer cells. Oncol Rep, 28, 1475-81. https://doi.org/10.3892/or.2012.1920
  11. Seto M, Ohta M, Ikenoue T, et al (2011). Reduced expression of RAS protein activator like-1 in gastric cancer. Int J Cancer, 128, 1293-302. https://doi.org/10.1002/ijc.25459

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