Prolactin and Dehydroepiandrosterone Levels in Women with Systemic Lupus Erythematosus: The Role of the Extrapituitary Prolactin Promoter Polymorphism at −1149G/T

Systemic lupus erythematosus (SLE) has shown an association with high levels of prolactin, low levels of dehydroepiandrosterone (DHEA), and induction of inflammatory cytokines in the serum of patients with the disease. This preliminary study examined the relevance of a −1149G/T functional single-nucleotide polymorphism (SNP) (rs1341239) in the promoter of the extrapituitary prolactin gene in a cohort of African American and European American women with lupus. Examination of this SNP revealed that the −1149TT genotype was correlated with higher levels of prolactin in serum and prolactin gene expression (p = 0.0001) in peripheral blood mononuclear cells (PBMCs). Lower levels of DHEA in serum were demonstrated in lupus patients (p = 0.001); those with the −1149TT genotype had the lowest levels of DHEA. Furthermore, a small subset of women who were on DHEA therapy and had a TT genotype showed a significant decrease in prolactin gene expression and lower disease activity scores (SLEDAI). Lupus patients, particularly African Americans, had significantly higher levels of IL-6 (p = 0.0001) and TNF-α (p = 0.042). This study suggests that the −1149TT genotype may be a risk factor for lupus and may predict who could possibly benefit from DHEA therapy; therefore, these results should be validated in a larger cohort with all ethnic groups

Ethnic differences in DNA methyltransferases expression in patients with systemic lupus erythematosus

Systemic lupus erythematous (SLE) is a systemic autoimmune inflammatory disease with both genetic and epigenetic etiologies. Evidence suggests that deregulation of specific genes through epigenetic mechanisms may be a contributing factor to SLE pathology. There is increasing evidence that DNA methyltransferase activity may be involved. This study demonstrated modulation in expression of DNA methyltransferases (DNMTs) according to ethnicity in patients diagnosed with SLE. Furthermore, differential expression in one of the DNMTs was found in a subset of lupus patients on dehydroepiandrosterone (DHEA) therapy. Real-time PCR analyses of DNMT1, DNMT3A and DNMT3B in peripheral blood mononuclear cells from a cohort of African American and European American lupus and non-lupus women were conducted. Also, global DNA methylation was assessed using the MethylFlash.sup.TM methylated quantification colorimetric assay. These findings suggest that epigenetic changes may play a critical role in the manifestations of the disease observed among ethnic groups, particularly African American women who often have a higher incidence of lupus. DHEA therapy effects on DNMT3A expression in AA women warrant further investigation in a larger population

Effect of cigarette smoke condensate on gene promoter methylation in human lung cells

Background In lung cancer, an association between tobacco smoking and promoter DNA hypermethylation has been demonstrated for several genes. However, underlying mechanisms for promoter hypermethylation in tobacco-induced cancer are yet to be fully established. Methods Promoter methylation was evaluated in control and cigarette smoke condensate (CSC) exposed human lung cells using the Methyl-Profiler DNA Methylation PCR System. PSAE cells were exposed to 0.3 or 1.0 μg/ml CSC for 72 hours and longer term for 14 and 30 days. NL-20 cells were exposed for 30 days to 10 or 100 μg/ml CSC. Results Promoters of several genes, including hsa-let-7a-3, CHD1, CXCL12, PAX5, RASSF2, and TCF21, were highly methylated (>90%); hsa-let-7a-3 was affected in both cell lines and under all exposure conditions. Level of methylation tended to increase with CSC concentration and exposure duration (statistical differences were not determined). Percentage methylation of TCF21, which was >98% at exposures of 10 or 100 μg/ml CSC, was found to be reduced to 28% and 42%, respectively, in the presence of the dietary agent genistein. Conclusions Using array techniques, several tumor suppressor genes in human lung cells were identified that undergo promoter hypermethylation, providing further evidence of their potential involvement in tobacco smoke-induced lung carcinogenesis and their use as potential biomarkers of harm in tobacco smoke exposure. Results from the study also demonstrated the potential of a dietary agent to exert chemopreventive activity in human tissue against tobacco smoke related diseases through modulation of DNA methylation. Additional studies are needed to confirm these findings

Cigarette smoke condensate and individual constituents modulate DNA methyltransferase expression in human liver cells

Objectives: Previous studies found higher expression levels of DNA methyltransferase 1 in liver samples from smokers compared to those from non-smokers. In contrast, expression levels of DNA methyltransferase 3a and DNA methyltransferase 3b were similar in smokers and non-smokers. This study extends these studies to establish a causal linkage to cigarette smoke exposure by examining whether DNA methyltransferase expression is modulated by cigarette smoke condensate. Methods: These experiments were conducted in an in vitro system using HepG2 human liver cells. The dose range of cigarette smoke condensate was 0.1–120 µg/mL. The duration of exposure was up to 72 h. Results: In a 24-h exposure, DNA methyltransferase 1 expression was found to increase significantly in a dose-dependent manner (greater than threefold at 100 µg/mL cigarette smoke condensate). Expression levels of DNA methyltransferase 3a and DNA methyltransferase 3b were, however, not affected under these conditions. The effect of two cigarette constituents, nicotine and cotinine, on DNA methyltransferase 1 expression was also examined. Nicotine exposure significantly increased DNA methyltransferase 1 expression in a dose-dependent manner (greater than twofold at 50 µM). However, under these conditions, cotinine did not increase DNA methyltransferase 1 expression. Conclusion: These results clearly provide additional support of the modulating effect of cigarette smoke on DNA methyltransferase 1 expression. Given the potential of alterations in DNA methyltransferase expression to affect cellular function, this pathway may play a critical role in cigarette smoke-induced toxicity

Restoration of the methylation status of hypermethylated gene promoters by microRNA-29b in human breast cancer: A novel epigenetic therapeutic approach

It is well established that transcriptional silencing of critical tumor-suppressor genes by DNA methylation is a fundamental component in the initiation of breast cancer. However, the involvement of microRNAs (miRNAs) in restoring abnormal DNA methylation patterns in breast cancer is not well understood. Therefore, we investigated whether miRNA-29b, due to its complimentarity to the 3′- untranslated region of DNA methyltransferase 3A (DNMT3A) and DNMT3B, could restore normal DNA methylation patterns in human breast cancers and breast cancer cell lines. We demonstrated that transfection of pre-miRNA-29b into less aggressive MCF-7 cells, but not MDA-MB-231 mesenchymal cells, inhibited cell proliferation, decreased DNMT3A and DNMT3B messenger RNA (mRNA), and decreased promoter methylation status of ADAM23 , CCNA1, CCND2, CDH1, CDKN1C, CDKN2A, HIC1, RASSF1, SLIT2, TNFRSF10D, and TP73 tumor-suppressor genes. Using methylation polymerase chain reaction (PCR) arrays and real-time PCR, we also demonstrated that the methylation status of several critical tumor-suppressor genes increased as stage of breast disease increased, while miRNA-29b mRNA levels were significantly decreased in breast cancers versus normal breast. This increase in methylation status was accompanied by an increase in DNMT1 and DNMT3B mRNA in advanced stage of human breast cancers and in MCF-7, MDA-MB-361, HCC70, Hs-578T, and MDA-MB-231 breast cancer cells as compared to normal breast specimens and MCF-10-2A, a non-tumorigenic breast cell line, respectively. Our findings highlight the potential for a new epigenetic approach in improving breast cancer therapy by targeting DNMT3A and DNMT3B through miRNA-29b in non-invasive epithelial breast cancer cells

ATP-Binding Cassette Genes Genotype and Expression: A Potential Association with Pancreatic Cancer Development and Chemoresistance?

Genetic polymorphisms in ABC (ATP-binding cassette) transporter genes are associated with differential responses to chemotherapy in various cancers including pancreatic cancer. In this study, four SNPs in the ABCB1, ABCC1, and ABCG2 genes were investigated in normal and pancreatic cancerous specimens. The expression of the three transporters was also analyzed. The TT genotypes of G2677T and C3435T in ABCB1 gene were associated with lower risk of developing pancreatic cancer (P=0.013, OR = 0.35 and P=0.015, OR = 0.29, resp.). To our knowledge, this is the first report of the common polymorphisms in the ABCB1 gene affecting the genetic risk of developing pancreatic cancer. Moreover, the expression of ABCB1 in 2677TT and 3435TT carriers was lower compared to the wild-type homozygotes and heterozygotes. A cell viability assay, using standard pancreatic cancer cell lines, revealed that the ABCB1 2677TT-3455TT haplotype was more sensitive than the other haplotypes to gemcitabine. Conclusion. Polymorphisms in ABCB1 G2677T and G3435T were associated with differential susceptibility to pancreatic cancer and may predict responses to chemotherapy

Ethnic differences in DNA methyltransferases expression in patients with systemic lupus erythematosus

Systemic lupus erythematous (SLE) is a systemic autoimmune inflammatory disease with both genetic and epigenetic etiologies. Evidence suggests that deregulation of specific genes through epigenetic mechanisms may be a contributing factor to SLE pathology. There is increasing evidence that DNA methyltransferase activity may be involved. This study demonstrated modulation in expression of DNA methyltransferases (DNMTs) according to ethnicity in patients diagnosed with SLE. Furthermore, differential expression in one of the DNMTs was found in a subset of lupus patients on dehydroepiandrosterone (DHEA) therapy. Real-time PCR analyses of DNMT1, DNMT3A and DNMT3B in peripheral blood mononuclear cells from a cohort of African American and European American lupus and non-lupus women were conducted. Also, global DNA methylation was assessed using the MethylFlash.sup.TM methylated quantification colorimetric assay. These findings suggest that epigenetic changes may play a critical role in the manifestations of the disease observed among ethnic groups, particularly African American women who often have a higher incidence of lupus. DHEA therapy effects on DNMT3A expression in AA women warrant further investigation in a larger population

Prolactin and Dehydroepiandrosterone Levels in Women with Systemic Lupus Erythematosus: The Role of the Extrapituitary Prolactin Promoter Polymorphism at −1149G/T

Systemic lupus erythematosus (SLE) has shown an association with high levels of prolactin, low levels of dehydroepiandrosterone (DHEA), and induction of inflammatory cytokines in the serum of patients with the disease. This preliminary study examined the relevance of a −1149G/T functional single-nucleotide polymorphism (SNP) (rs1341239) in the promoter of the extrapituitary prolactin gene in a cohort of African American and European American women with lupus. Examination of this SNP revealed that the −1149TT genotype was correlated with higher levels of prolactin in serum and prolactin gene expression (p = 0.0001) in peripheral blood mononuclear cells (PBMCs). Lower levels of DHEA in serum were demonstrated in lupus patients (p = 0.001); those with the −1149TT genotype had the lowest levels of DHEA. Furthermore, a small subset of women who were on DHEA therapy and had a TT genotype showed a significant decrease in prolactin gene expression and lower disease activity scores (SLEDAI). Lupus patients, particularly African Americans, had significantly higher levels of IL-6 (p = 0.0001) and TNF-a (p = 0.042). This study suggests that the −1149TT genotype may be a risk factor for lupus and may predict who could possibly benefit from DHEA therapy; therefore, these results should be validated in a larger cohort with all ethnic groups

Prolactin and Dehydroepiandrosterone Levels in Women with Systemic Lupus Erythematosus: The Role of the Extrapituitary Prolactin Promoter Polymorphism at -1149G/T

Systemic lupus erythematosus (SLE) has shown an association with high levels of prolactin, low levels of dehydroepiandrosterone (DHEA), and induction of inflammatory cytokines in the serum of patients with the disease. This preliminary study examined the relevance of a -1149G/T functional single-nucleotide polymorphism (SNP) (rs1341239) in the promoter of the extrapituitary prolactin gene in a cohort of African American and European American women with lupus. Examination of this SNP revealed that the -1149TT genotype was correlated with higher levels of prolactin in serum and prolactin gene expression (p = 0.0001) in peripheral blood mononuclear cells (PBMCs). Lower levels of DHEA in serum were demonstrated in lupus patients (p = 0.001)\; those with the -1149TT genotype had the lowest levels of DHEA. Furthermore, a small subset of women who were on DHEA therapy and had a TT genotype showed a significant decrease in prolactin gene expression and lower disease activity scores (SLEDAI). Lupus patients, particularly African Americans, had significantly higher levels of IL-6 (p = 0.0001) and TNF-a (p = 0.042). This study suggests that the -1149TT genotype may be a risk factor for lupus and may predict who could possibly benefit from DHEA therapy\; therefore, these results should be validated in a larger cohort with all ethnic groups