Hongbo Fang1, Jing Liu2, Dan Guo1, Peixiang Liu3, Yongliang Zhao1. 1. Center for Genome Variations and Precision Bio-Medicine, Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing 100029, China. 2. Center for Genome Variations and Precision Bio-Medicine, Beijing Institute of Genomics, University of Chinese Academy of Sciences, Beijing 100049, China. 3. Department of Clinical Laboratory, First People's Hospital of Yueyang, Yueyang, Hunan 414000, China.
Abstract
BACKGROUND: Both in vitro and in vivo data have demonstrated the TGFBI gene functions as a putative tumor suppressor and is frequently downregulated in human tumors of different histological types. The hypermethylation of the TGFBI promoter, as one of the main regulatory mechanisms, is associated with TGFBI silencing. In this study, we used a methylation-specific PCR (MSP) method to evaluate the methylation status of the TGFBI promoter in human leukemias. METHODS: Real-time RT-PCR and methylation-specific PCR approaches were performed to define the TGFBI expression and promoter methylation in human leukemia cell lines and clinical samples. Genomic DNA was isolated from peripheral blood mononuclear cells from leukemia patients, bisulfite-converted, and analyzed by the MSP method. RESULTS: Hypermethylation of the TGFBI promoter occurred in leukemia cell lines and demethylation treatment reexpressed TGFBI at a substantially increased level in most of leukemia cell lines tested. Furthermore, a much higher level of CpG island methylation and a significantly lower TGFBI expression were also identified in clinical leukemia samples. CONCLUSION: The results suggest an important role of promoter methylation in regulating TGFBI expression in leukemia, which provides a useful diagnostic marker for clinical management of human leukemias.
BACKGROUND: Both in vitro and in vivo data have demonstrated the TGFBI gene functions as a putative tumor suppressor and is frequently downregulated in humantumors of different histological types. The hypermethylation of the TGFBI promoter, as one of the main regulatory mechanisms, is associated with TGFBI silencing. In this study, we used a methylation-specific PCR (MSP) method to evaluate the methylation status of the TGFBI promoter in humanleukemias. METHODS: Real-time RT-PCR and methylation-specific PCR approaches were performed to define the TGFBI expression and promoter methylation in humanleukemia cell lines and clinical samples. Genomic DNA was isolated from peripheral blood mononuclear cells from leukemiapatients, bisulfite-converted, and analyzed by the MSP method. RESULTS: Hypermethylation of the TGFBI promoter occurred in leukemia cell lines and demethylation treatment reexpressed TGFBI at a substantially increased level in most of leukemia cell lines tested. Furthermore, a much higher level of CpG island methylation and a significantly lower TGFBI expression were also identified in clinicalleukemia samples. CONCLUSION: The results suggest an important role of promoter methylation in regulating TGFBI expression in leukemia, which provides a useful diagnostic marker for clinical management of humanleukemias.