AIM:To investigate the methylation status of secreted protein acidic and rich in cysteine(SPARC) in human hepatocellular carcinoma(HCC) and evaluate its clinical implication.METHODS:The methylation status of SPARC was...AIM:To investigate the methylation status of secreted protein acidic and rich in cysteine(SPARC) in human hepatocellular carcinoma(HCC) and evaluate its clinical implication.METHODS:The methylation status of SPARC was analyzed in one HCC cell line(SMMC-7721) and 60 pairs of HCC and corresponding nontumorous tissues by methylation-specific polymerase chain reaction and bisulfite sequencing.The expression of SPARC mRNA and protein were examined by reverse transcription polymerase chain reaction and immunohistochemistry,respectively.The correlations between the methylation status and the gene expression,the clinicopathological parameters,as well as the prognosis after surgery were analyzed.RESULTS:In the SMMC-7721 cell line,the loss of SPARC expression was correlated with the aberrant methylation and could be reactivated by the demethylating agent 5-aza-2'-deoxycytidine.Methylation frequency of SPARC in HCC was significantly higher than that in the corresponding nontumorous tissues(45/60 vs 7/60,P < 0.001),and it was correlated with the pathological classification(P = 0.019).The downregulation of the SPARC mRNA expression in HCC was correlated with the SPARC methylation(P = 0.040).The patients with methylated SPARC had a poorer overall survival than those without methylated SPARC(28.0 mo vs 41.0 mo,P = 0.043).CONCLUSION:Aberrant methylation is an important mechanism for SPARC inactivation in HCC and SPARC methylation may be a promising biomarker for the diagnosis and prognosis of HCC.展开更多
Melanoma is the deadliest form of skin cancer with rising incidence and mortality rates. Although early-stage melanoma is highly curable, advanced-stage melanoma is refractory to treatment. This underscores the import...Melanoma is the deadliest form of skin cancer with rising incidence and mortality rates. Although early-stage melanoma is highly curable, advanced-stage melanoma is refractory to treatment. This underscores the importance of prevention and early detection as well as the need to improve treatment and prognostication of human melanoma. Elucidating the underlying mechanisms of the initi- ation and progression of human melanoma can help identify potential targets of intervention for prevention, diagnosis, therapy, and prognosis of this disease. Aberrant DNA methylation and histone modifications are the best-established epigenetic mechanisms of carcinogenesis. The occurrence of epigenetic changes prior to clinical diagnosis of cancer and their reversibility through pharmaco-logic/genetic approaches offer a promising avenue for basic and translational research on human melanoma. Candidate gene（s） or genome-wide aberrant DNA methylation and histone modifications have been observed in human melanoma tumor tissues and cell lines, and correlated to cellular and functional characteristics and/or clinicopathologicai features of this malignancy. The present review summarizes the published researches on aberrant DNA methylation and histone modifications in connection with human melanoma. Representative studies are highlighted to set forth the current state of knowledge, gaps in the knowledgebase, and future directions in these epigenetic fields of research. Examples of epigenetic therapy applied for human melanoma in vitro, and the challenges of its in vivo application for clinical treatment of solid tumors are discussed.展开更多
基金Supported by Tianjin Health Bureau for research projects,No.09KY04,No.2010KZ17 and No.11KG112
文摘AIM:To investigate the methylation status of secreted protein acidic and rich in cysteine(SPARC) in human hepatocellular carcinoma(HCC) and evaluate its clinical implication.METHODS:The methylation status of SPARC was analyzed in one HCC cell line(SMMC-7721) and 60 pairs of HCC and corresponding nontumorous tissues by methylation-specific polymerase chain reaction and bisulfite sequencing.The expression of SPARC mRNA and protein were examined by reverse transcription polymerase chain reaction and immunohistochemistry,respectively.The correlations between the methylation status and the gene expression,the clinicopathological parameters,as well as the prognosis after surgery were analyzed.RESULTS:In the SMMC-7721 cell line,the loss of SPARC expression was correlated with the aberrant methylation and could be reactivated by the demethylating agent 5-aza-2'-deoxycytidine.Methylation frequency of SPARC in HCC was significantly higher than that in the corresponding nontumorous tissues(45/60 vs 7/60,P < 0.001),and it was correlated with the pathological classification(P = 0.019).The downregulation of the SPARC mRNA expression in HCC was correlated with the SPARC methylation(P = 0.040).The patients with methylated SPARC had a poorer overall survival than those without methylated SPARC(28.0 mo vs 41.0 mo,P = 0.043).CONCLUSION:Aberrant methylation is an important mechanism for SPARC inactivation in HCC and SPARC methylation may be a promising biomarker for the diagnosis and prognosis of HCC.
文摘Melanoma is the deadliest form of skin cancer with rising incidence and mortality rates. Although early-stage melanoma is highly curable, advanced-stage melanoma is refractory to treatment. This underscores the importance of prevention and early detection as well as the need to improve treatment and prognostication of human melanoma. Elucidating the underlying mechanisms of the initi- ation and progression of human melanoma can help identify potential targets of intervention for prevention, diagnosis, therapy, and prognosis of this disease. Aberrant DNA methylation and histone modifications are the best-established epigenetic mechanisms of carcinogenesis. The occurrence of epigenetic changes prior to clinical diagnosis of cancer and their reversibility through pharmaco-logic/genetic approaches offer a promising avenue for basic and translational research on human melanoma. Candidate gene（s） or genome-wide aberrant DNA methylation and histone modifications have been observed in human melanoma tumor tissues and cell lines, and correlated to cellular and functional characteristics and/or clinicopathologicai features of this malignancy. The present review summarizes the published researches on aberrant DNA methylation and histone modifications in connection with human melanoma. Representative studies are highlighted to set forth the current state of knowledge, gaps in the knowledgebase, and future directions in these epigenetic fields of research. Examples of epigenetic therapy applied for human melanoma in vitro, and the challenges of its in vivo application for clinical treatment of solid tumors are discussed.
