PURPOSE: Laminin-5 (LN5) is an essential component of the basement membrane (BM) and is composed of three chains that are the products of three distinct genes (LAMA3, LAMB3, and LAMC2). Differential expression of LN5 genes has been reported in prostate and other cancers. Recently, in lung cancers, we developed methylation-specific PCR assays for each gene and demonstrated that the aberrant methylation as the mechanism of inactivation of genes. In this study, we investigated the aberrant promoter methylation of LN5 genes in prostate cancers and correlated the data with clinicopathological features. EXPERIMENTAL DESIGN: Promoter methylation of LN5-encoding genes was analyzed in 101 prostate cancer samples by methylation-specific PCR assay. In addition, we analyzed 32 nonmalignant prostate tissue samples. The methylation index (MI) was determined as the methylated fraction of the genes examined. RESULTS: The frequencies of loss of expression for the LAMA3, LAMB3, and LAMC2 genes in six prostate cancer cell lines were 83, 67, and 50%, respectively, whereas the methylation frequencies were 83, 67, and 33%, respectively. The concordances between loss of expression and methylation for the three genes were 100, 100, and 83%, respectively. The frequency of methylation of LN5-encoding genes in prostate cancers and nonmalignant prostate tissues, respectively, were: 44 and 12% for LAMA3 (P = 0.001); 18 and 6% for LAMB3; and 41 and 9% for LAMC2 (P = 0.001). In addition, methylation frequencies of any one or two genes, frequencies of at least one-gene methylation and mean chain MI were significantly higher in prostate cancers than in nonmalignant prostate tissues. For clinicopathological correlations, the high Gleason score (GS) group, high preoperative serum prostate-specific antigen (PSA) group, and high stage group had significantly higher methylation frequencies of LAMA3 than their corresponding low groups. Methylation frequency of at least one gene and mean chain MI was significantly higher in the high PSA group and high-stage group than their respective low groups. There was significant correlation between MI and PSA. The high GS group had higher frequencies of at least one gene methylation and mean chain MI than the low GS group. CONCLUSIONS: Our results demonstrate frequent epigenetic silencing of LN5-encoding genes in prostate cancers and it correlates with clinicopathological features of poor prognosis. These findings are of biological interest and potentially of clinical importance.
PURPOSE: Laminin-5 (LN5) is an essential component of the basement membrane (BM) and is composed of three chains that are the products of three distinct genes (LAMA3, LAMB3, and LAMC2). Differential expression of LN5 genes has been reported in prostate and other cancers. Recently, in lung cancers, we developed methylation-specific PCR assays for each gene and demonstrated that the aberrant methylation as the mechanism of inactivation of genes. In this study, we investigated the aberrant promoter methylation of LN5 genes in prostate cancers and correlated the data with clinicopathological features. EXPERIMENTAL DESIGN: Promoter methylation of LN5-encoding genes was analyzed in 101 prostate cancer samples by methylation-specific PCR assay. In addition, we analyzed 32 nonmalignant prostate tissue samples. The methylation index (MI) was determined as the methylated fraction of the genes examined. RESULTS: The frequencies of loss of expression for the LAMA3, LAMB3, and LAMC2 genes in six prostate cancer cell lines were 83, 67, and 50%, respectively, whereas the methylation frequencies were 83, 67, and 33%, respectively. The concordances between loss of expression and methylation for the three genes were 100, 100, and 83%, respectively. The frequency of methylation of LN5-encoding genes in prostate cancers and nonmalignant prostate tissues, respectively, were: 44 and 12% for LAMA3 (P = 0.001); 18 and 6% for LAMB3; and 41 and 9% for LAMC2 (P = 0.001). In addition, methylation frequencies of any one or two genes, frequencies of at least one-gene methylation and mean chain MI were significantly higher in prostate cancers than in nonmalignant prostate tissues. For clinicopathological correlations, the high Gleason score (GS) group, high preoperative serum prostate-specific antigen (PSA) group, and high stage group had significantly higher methylation frequencies of LAMA3 than their corresponding low groups. Methylation frequency of at least one gene and mean chain MI was significantly higher in the high PSA group and high-stage group than their respective low groups. There was significant correlation between MI and PSA. The high GS group had higher frequencies of at least one gene methylation and mean chain MI than the low GS group. CONCLUSIONS: Our results demonstrate frequent epigenetic silencing of LN5-encoding genes in prostate cancers and it correlates with clinicopathological features of poor prognosis. These findings are of biological interest and potentially of clinical importance.
Authors: Jiaqi Mi; Erika Hooker; Steven Balog; Hong Zeng; Daniel T Johnson; Yongfeng He; Eun-Jeong Yu; Huiqing Wu; Vien Le; Dong-Hoon Lee; Joseph Aldahl; Mark L Gonzalgo; Zijie Sun Journal: J Biol Chem Date: 2018-11-06 Impact factor: 5.157
Authors: Han Han; Connie C Cortez; Xiaojing Yang; Peter W Nichols; Peter A Jones; Gangning Liang Journal: Hum Mol Genet Date: 2011-08-11 Impact factor: 6.150
Authors: Cynthia C T Sprenger; Rolf H Drivdahl; Lillie B Woodke; Daniel Eyman; May J Reed; William G Carter; Stephen R Plymate Journal: Neoplasia Date: 2008-12 Impact factor: 5.715