Adipogenic effects of prenatal exposure to bisphenol S (BPS) in adult F1 male mice.

Bisphenol S (BPS) has been increasingly used as a substitute for bisphenol A (BPA), a known endocrine disruptor. Early-life exposure to BPA affects fetal development and the risk of obesity in adolescence and adulthood. However, the effects of fetal exposure BPS in later life are unknown. This study aimed to investigate the effects of prenatal BPS exposure on adiposity in adult F1 mice. Pregnant C57BL/6 N mice were exposed to BPS (0, 0.05, 0.5, 5, and 50 mg/kg/d) via drinking water from gestation day 9 until delivery. Thereafter, two groups of offspring (6 weeks old) were either administered a standard diet (STD) or a high-fat diet (HFD) for 4 weeks until euthanasia. The body weight and gonadal white adipose tissue (gWAT) mass were determined, and the energy expenditure for the adiposity phenotype was computed especially for male mice, followed by histological analysis of the gWAT. Thereafter, the expression levels of adipogenic marker genes (Pparg, Cebpa, Fabp4, Lpl, and Adipoq) were analyzed in the gWAT via reverse-transcription PCR analysis. BPS-exposed male mice displayed apparent gWAT hypertrophy, consistent with the significant increase in adipocyte size in the gWAT and upregulation of Pparg and its direct target genes among HFD mice in comparison with the control mice. These results suggest that prenatal BPS exposure potentially increases the susceptibility to HFD-induced adipogenesis in male adult mice.

Epigenetic Regulation of Filaggrin Gene Expression in Human Epidermal Keratinocytes.

BACKGROUND: Loss-of-function mutations in the filaggrin gene (FLG), which encodes an epidermal protein crucial for the formation of a functional skin barrier, have been identified as a major predisposing factor in the etiopathogenesis of atopic dermatitis (AD). Recent reports of relatively low frequencies of FLG-null mutations among specific ethnic groups with AD necessitated analysis of the epigenetic regulation which may control FLG expression without altering its DNA sequence. OBJECTIVE: The study aimed to identify DNA methylation-dependent regulation of FLG expression. METHODS: Quantitative polymerase chain reaction was performed to determine the restoration of FLG mRNA expression in normal human epidermal keratinocyte (NHEK) cells after treatment with epigenetic modulating agents. Bisulfite genomic sequencing and pyrosequencing analyses of the FLG promoter region were conducted to identify the citical CpG sites relevant to FLG expression. We performed small-scale pilot study for epidermal tissues obtained from Korean patients with severe AD. RESULTS: We here show that DNA methylation in the FLG with non-CpG island promoter is responsible for the transcriptional regulation of FLG in undifferentiated NHEK cells. The methylation frequencies in a single CpG site of the FLG promoter were significantly higher in lesional epidermis than those in matched nonlesional epidermis of subjects with severe AD. CONCLUSION: Our in vitro and clinical studies point to this unique CpG site as a potential DNA methylation marker of FLG, which can be a promising therapeutic target in the complications of filaggrin-related skin barrier dysfunction as well as in AD.

Promoter DNA methylation contributes to human ß-defensin-1 deficiency in atopic dermatitis.

Atopic dermatitis (AD) is a chronic inflammatory skin disease caused by epidermal barrier dysfunction and dysregulation of innate and adaptive immunity. Epigenetic regulation of human ß-defensin-1 (HBD-1) might be associated with a variety of defects in the innate immune system during AD pathogenesis. We investigated the possible mechanism of decreased HBD-1 gene expression in AD and demonstrated the restoration of HBD-1 transcription in undifferentiated normal human epidermal keratinocyte cells after treatment with a DNA methyltransferase inhibitor. We also conducted an in vitro methylated reporter assay using a reporter containing 14 CpG sites. Methylation of the 14 CpG sites within the HBD-1 5' region resulted in an approximately 86% reduction in promoter activity and affected HBD-1 transcriptional regulation. We then compared methylation frequencies at CpG 3 and CpG 4 between non-lesional and lesional epidermis samples of patients with severe AD and between these paired tissues and healthy control epidermis from normal volunteers without AD history. Bisulfite pyrosequencing data showed significantly higher methylation frequencies at the CpG 3 and 4 sites in AD lesional samples than in non-lesional AD skin and normal skin samples (P < 0.05). These results suggest that the DNA methylation signature of HBD-1 is a novel diagnostic/prognostic marker and a promising therapeutic target for the compromised stratum corneum barrier attributed to HBD-1 deficiency.

Distinct Histone Modifications Modulate DEFB1 Expression in Human Vaginal Keratinocytes in Response to Lactobacillus spp.

Vaginal commensal lactobacilli are considered to contribute significantly to the control of vaginal microbiota by competing with other microflora for adherence to the vaginal epithelium and by producing antimicrobial compounds. However, the molecular mechanisms of symbiotic prokaryotic-eukaryotic communication in the vaginal ecosystem remain poorly understood. Here, we showed that both DNA methylation and histone modifications were associated with expression of the DEFB1 gene, which encodes the antimicrobial peptide human ß-defensin-1, in vaginal keratinocyte VK2/E6E7 cells. We investigated whether exposure to Lactobacillus gasseri and Lactobacillus reuteri would trigger the epigenetic modulation of DEFB1 expression in VK2/E6E7 cells in a bacterial species-dependent manner. While enhanced expression of DEFB1 was observed when VK2/E6E7 cells were exposed to L. gasseri, treatment with L. reuteri resulted in reduced DEFB1 expression. Moreover, L. gasseri stimulated the recruitment of active histone marks and, in contrast, L. reuteri led to the decrease of active histone marks at the DEFB1 promoter. It was remarkable that distinct histone modifications within the same promoter region of DEFB1 were mediated by L. gasseri and L. reuteri. Therefore, our study suggested that one of the underlying mechanisms of DEFB1 expression in the vaginal ecosystem might be associated with the epigenetic crosstalk between individual Lactobacillus spp. and vaginal keratinocytes.

Epigenetic suppression of the anti-aging gene KLOTHO in human prostate cancer cell lines.

KLOTHO was originally identified as an aging-suppressor gene that causes a human aging-like phenotype when tested in KLOTHO-deficient-mice. Recent evidence suggests that KLOTHO functions as a tumor suppressor by inhibiting Wnt signaling. KLOTHO gene silencing, including DNA methylation, has been observed in some human cancers. Aberrant activation of Wnt signaling plays a significant role in aging, and its silencing may be related to prostate cancer and other types of cancers. Thus, we investigated whether the expression of the anti-aging gene KLOTHO was associated with epigenetic changes in prostate cancer cell lines. KLOTHO mRNA was detected in the 22Rv1 cell line while it was not detected in DU145 and PC-3 cell lines. The restoration of KLOTHO mRNA in the DU145 and PC-3 cell lines was induced with a DNA methyltransferase inhibitor. Methylation-specific PCR was performed to determine the specific CpG sites in the KLOTHO promoter responsible for expression. In addition, the level of methylation was assessed in each CpG by performing bisulfite sequencing and quantitative pyrosequencing analysis. The results suggested a remarkable inverse relationship between KLOTHO expression and promoter methylation in prostate cancer cell lines.

DNA Methylation-Mediated Downregulation of DEFB1 in Prostate Cancer Cells.

Epigenetic aberrations play crucial roles in prostate cancer (PCa) development and progression. The DEFB1 gene, which encodes human ß-defensin-1 (HBD-1), contributes to innate immune responses and functions as a potential tumor suppressor in urological cancers. We investigated whether differential DNA methylation at the low CpG-content promoter (LCP) of DEFB1 was associated with transcriptional regulation of DEFB1 in PCa cells. To identify distinct CpG loci within the DEFB1 LCP related to the epigenetic regulation of DEFB1, we performed an in vitro methylated reporter assay followed by bisulfite sequencing of the DEFB1 promoter fragment. The methylation status of two adjacent CpG loci in the DEFB1 LCP was found to be important for DEFB1 expression in PCa cells. Paired epithelial specimens of PCa patients (n = 60), which were distinguished as non-tumor and tumor tissues by microdissection, were analyzed by bisulfite pyrosequencing of site-specific CpG dinucleotide units in the DEFB1 LCP. CpG methylation frequencies in the DEFB1 LCP were significantly higher in malignant tissues than in adjacent benign tissues across almost all PCa patients. These results suggested that methylation status of each CpG site in the DEFB1 promoter could mediate downregulation of DEFB1 in PCa cells.

Expression of Beta-Defensin 131 Promotes an Innate Immune Response in Human Prostate Epithelial Cells.

Previously, using the Illumina HumanHT-12 microarray we found that ß-defensin 131 (DEFB131), an antimicrobial peptide, is upregulated in the human prostate epithelial cell line RWPE-1 upon stimulation with lipoteichoic acid (LTA; a gram-positive bacterial component), than that in the untreated RWPE-1 cells. In the current study, we aimed to investigate the role of DEFB131 in RWPE-1 cells during bacterial infection. We examined the intracellular signaling pathways and nuclear responses in RWPE-1 cells that contribute to DEFB131 gene induction upon stimulation with LTA. Chromatin immunoprecipitation was performed to determine whether NF-κB directly binds to the DEFB131 promoter after LTA stimulation in RWPE-1 cells. We found that DEFB131 expression was induced by LTA stimulation through TLR2 and p38MAPK/NF-κB activation, which was evident in the phosphorylation of both p38MAPK and IκBα. We also found that SB203580 and Bay11-7082, inhibitors of p38MAPK and NF-κB, respectively, suppressed LTA-induced DEFB131 expression. The chromatin immunoprecipitation assay showed that NF-κB directly binds to the DEFB131 promoter, suggesting that NF-κB is a direct regulator, and is necessary for LTA-induced DEFB131 expression in RWPE-1 cells. Interestingly, with DEFB131 overexpression in RWPE-1 cells, the accumulation of mRNA and protein secretion of cytokines (IL-1α, IL-1ß, IL-6, and IL-12α) and chemokines (CCL20, CCL22, and CXCL8) were significantly enhanced. In addition, DEFB131-transfected RWPE-1 cells markedly induced chemotactic activity in THP-1 monocytes. We concluded that DEFB131 induces cytokine and chemokine upregulation through the TLR2/NF-κB signaling pathway in RWPE-1 cells during bacterial infection and promotes an innate immune response.

The association between KL polymorphism and prostate cancer risk in Korean patients.

The Klotho (KL) gene is a classical "aging suppressor" gene. Although recent studies have shown that KL participates in the progression of several types of human cancers, the relationship between KL polymorphism and prostate cancer was unknown. The present study aimed to investigate the association between KL genetic polymorphisms and prostate cancer. Twenty-five common single nucleotide polymorphisms (SNPs) in KL gene (including KL gene polymorphism C1818T in exon 4) were assessed in 272 prostate cancer cases and 173 controls. Single-locus analyses were conducted using unconditional logistic regression. In addition, we did a haplotype analysis for the 25 KL SNPs tested. CC genotype of C1548T KL polymorphism had approximately twofold increased prostate cancer risk compared with the homozygous genotype TT and heterozygote CT (odds ratio 1.85 [95% CI, 1.09-3.12], P = 0.02). We also found that non-T allele carriers had significantly higher prostate cancer risk associated with the prostate cancer clinical characteristics (tumor stage or Gleason score). Our findings suggested that the C1548T polymorphism of KL gene is associated with the prostate cancer and may act as a risk factor for the development of prostate cancer.

Beta-Defensin 124 Is Required for Efficient Innate Immune Responses in Prostate Epithelial RWPE-1 Cells.

PURPOSE: The present study aimed to determine the role played by ß-defensin 124 (DEFB124) in the innate immunity of prostate epithelial RWPE-1 cells during bacterial infection. MATERIALS AND METHODS: The expression of DEFB124 was examined by quantitative real-time polymerase chain reaction (PCR), Western blotting, and immunocytochemistry. Enzyme-linked immunosorbent assays and quantitative real-time PCR were performed to determine the production of cytokines and chemokines. Western blotting and chromatin immunoprecipitation studies were performed to assess the interaction between DEFB124 and nuclear factor-kappa B (NF-κB) in peptidoglycan (PGN)-stimulated RWPE-1 cells. By chemotaxis assay, we assessed the effect of DEFB124 on the migration of monocytes. RESULTS: Exposure to PGN induced DEFB124 upregulation and NF-κB activation through IκBα phosphorylation and IκBα degradation. Bay11-7082, an NF-κB inhibitor, blocked PGN-induced DEFB124 production. Also, NF-κB was shown to be a direct regulator and to directly bind to the -3.14 kb site of the DEFB124 promoter in PGN-treated human prostate epithelial RWPE-1 cells. When DEFB124 was overexpressed in RWPE-1 cells, interestingly, the production of cytokines (interleukin [IL] 6 and IL-12) and chemokines (CCL5, CCL22, and CXCL8) was significantly increased. These DEFB124-upregulated RWPE-1 cells markedly induced chemotactic activity for THP-1 monocytes. CONCLUSIONS: Taken together, these results provide strong evidence for the first time that increased DEFB124 expression via NF-κB activation in PGN-exposed RWPE-1 cells enhances the production of cytokines and chemokines, which may contribute to an efficient innate immune defense.

Single nucleotide polymorphisms in fibroblast growth factor 23 gene, FGF23, are associated with prostate cancer risk.

OBJECTIVE: To determine whether sequence variants within the FGF23 gene are associated with the risk of developing prostate cancer in a Korean population. PATIENTS AND METHODS: Five common single nucleotide polymorphisms (SNPs) in the FGF23 gene were assessed in 272 patients with prostate cancer and 173 control subjects with benign prostatic hyperplasia. Single-locus analyses were conducted using conditional logistic regression. In addition, we performed a haplotype analysis for the five FGF23 SNPs tested. RESULTS: Three SNPs in the FGF23 gene (rs11063118, rs13312789 and rs7955866) were associated with an increased risk of prostate cancer in our study population. Odds ratios for homozygous variants vs wild-type variants ranged from 1.68 (95% confidence interval [CI]: 1.15-2.46) to 1.79 (95% CI: 1.16-2.75). CONCLUSION: This is the first study showing that genetic variations in FGF23 increase prostate cancer susceptibility.

Sequence variants of Toll-like receptor 4 (TLR4) and the risk of prostate cancer in Korean men.

PURPOSE: Chronic inflammation has been considered a potential risk factor for prostate cancer. Toll-like receptors (TLRs) are important in the innate immune response to pathogens and in cross talk between innate immunity and adaptive immunity. In this study, sequence variants in the TLR4 gene were investigated to determine whether they were associated with prostate cancer risk in a Korean cohort. METHODS: An association study between 11 single-nucleotide polymorphisms (SNPs) of the TLR4 gene and prostate cancer was performed in 463 Korean male subjects including 240 prostate cancer patients and 223 healthy controls. SNPs were genotyped using the TaqMan assay, and their association with the risk of prostate cancer was evaluated using logistic regression analysis. RESULTS: The statistical analysis revealed that one SNP at the 3'UTR (rs11536889) showed significant association with the risk of prostate cancer (P (corr) = 0.005, OR = 1.81). One common haplotype (ht2) was also significantly associated with the risk of prostate cancer (P (corr) = 0.009, OR = 1.77). However, further analysis showed no association between any of the SNPs and prostate cancer prognostic factors such as the Gleason score or tumor stage. CONCLUSIONS: The findings of this study suggest that polymorphisms of the TLR4 gene might be associated with the risk of prostate cancer in Korean men.

HNF1B polymorphism associated with development of prostate cancer in Korean patients.

OBJECTIVE: To identify whether the genetic variations in HNF1B are associated with the development of prostate cancer in Korean patients. Genome-wide association studies have found the HNF1B gene at 17q12 to be a major causal gene for the risk of prostate cancer. METHODS: We evaluated the association of 47 single nucleotide polymorphisms (SNPs) in the HNF1B gene with prostate cancer risk and clinical characteristics (Gleason score and tumor stage) in Korean men (240 case subjects and 223 control subjects) using unconditional logistic regression analysis. RESULTS: Of the 47 SNPs, 14 were associated with prostate cancer risk (P = .002-.02); 9 SNPs were associated with a lower risk of prostate cancer (odds ratio 0.67-0.71, P = .005-.05), and 5 SNPs were associated with a greater risk of disease (odds ratio 1.49-1.51, P = .002-.02). In an analysis involving only patients with prostate cancer, 1 SNP (rs11868513) in the HNF1B gene was more frequent in patients with tumors with a greater stage than in those with a lower tumor stage. Two SNPs (rs4430796 and rs2074429) and 1 haplotype (Block3_ht1) were more frequent in patients with Gleason score of ≥7 than in those with Gleason score <6. CONCLUSION: As in studies from other populations, our findings indicate that HNF1B is also associated with prostate cancer risk in the Korean population.

Epigenetic regulation of the potential tumor suppressor gene, hLHX6.1, in human cervical cancer.

It is well known that the Homo sapiens LIM homeobox domain 6 gene (hLHX6), a putative transcription regulator, controls the differentiation and development of neural and lymphoid cells, particularly in the central nervous system. In this study, we investigated hLHX6.1 (an isoform of hLHX6), which functions as a tumor suppressor gene in the cervix. Firstly, the methylation levels of the hLHX6 and hLHX6.1 promoters were investigated in 8 cervical cancer cell lines and human tissue samples with a distinctive degree of malignant transformation. In spite of the presence of multiple cytosine guanine dinucleotides (CpG islands) in 2 proximal promoters of the hLHX6 and hLHX6.1 genes, only the hLHX6.1 promoters were found to be mostly hypermethylated and associated with transcriptional silencing by promoter methylation, whereas the hLHX6 promoters were not. Methylation levels in the hLHX6.1 promoter were also found to be strongly related to cervical cancer development. The level of hLHX6.1 gene expression was found to be relatively high in normal cells, in which the hLHX6.1 promoter was mostly unmethylated. However, the hLHX6.1 gene expression was down-regulated or undetectable in cervical cancer cell lines and cancer tissues, in which the hLHX6.1 promoter was hypermethylated. This epigenetic alteration in the hLHX6.1 promoter begins at a relatively early stage, suggesting its potential as a biomarker for the early diagnosis and prevention of cervical cancer. Moreover, the overexpression of the hLHX6.1 gene in cervical cancer cells suppressed the tumorigenic phenotype, as shown by soft agar colony formation and migration assays, suggesting that hLHX6.1 could be a new tumor suppressor gene in the cervix.

The anti-aging gene KLOTHO is a novel target for epigenetic silencing in human cervical carcinoma.

BACKGROUND: Klotho was originally characterized as an anti-aging gene that predisposed Klotho-deficient mice to a premature aging-like syndrome. Recently, KLOTHO was reported to function as a secreted Wnt antagonist and as a tumor suppressor. Epigenetic gene silencing of secreted Wnt antagonists is considered a common event in a wide range of human malignancies. Abnormal activation of the canonical Wnt pathway due to epigenetic deregulation of Wnt antagonists is thought to play a crucial role in cervical tumorigenesis. In this study, we examined epigenetic silencing of KLOTHO in human cervical carcinoma. RESULTS: Loss of KLOTHO mRNA was observed in several cervical cancer cell lines and in invasive carcinoma samples, but not during the early, preinvasive phase of primary cervical tumorigenesis. KLOTHO mRNA was restored after treatment with either the DNA demethylating agent 2'-deoxy-5-azacytidine or histone deacetylase inhibitor trichostatin A. Methylation-specific PCR and bisulfite genomic sequencing analysis of the promoter region of KLOTHO revealed CpG hypermethylation in non-KLOTHO-expressing cervical cancer cell lines and in 41% (9/22) of invasive carcinoma cases. Histone deacetylation was also found to be the major epigenetic silencing mechanism for KLOTHO in the SiHa cell line. Ectopic expression of the secreted form of KLOTHO restored anti-Wnt signaling and anti-clonogenic activity in the CaSki cell line including decreased active beta-catenin levels, suppression of T-cell factor/beta-catenin target genes, such as c-MYC and CCND1, and inhibition of colony growth. CONCLUSIONS: Epigenetic silencing of KLOTHO may occur during the late phase of cervical tumorigenesis, and consequent functional loss of KLOTHO as the secreted Wnt antagonist may contribute to aberrant activation of the canonical Wnt pathway in cervical carcinoma.

The role of hLHX6-HMR as a methylation biomarker for early diagnosis of cervical cancer.

The homo sapiens LIM homeobox domain LHX6 gene, hLHX6, is a putative transcription regulator with homeo-domain. Multiple cytosine guanine dinucleotides (CpG island) are found in the genomic sequences between exon 4a and exon 5 of the gene encoding hLHX6s (alternative short iso-form of hLHX6 gene). This specific CpG island, hLHX6-HMR, is found frequently hypermethylated in 7 cervical cancer cell lines as shown in MSP, BSP, and COBRA assays. Methylation densities were also investigated with human tissue samples with a distinctive degree of malignant transformation. Our data showed that the hLHX6-HMR was rarely or partly methylated in the normal and CIN I cells, respectively. In contrast, it was frequently hypermethylated in CIN II, CIN III, and invasive carcinoma cells. In summary, this methylation study led to two conclusions. First, hLHX6-HMR hypermethylation is exclusively associated with cervical carcinogenesis. Second, the epigenetic change in hLHX6-HMR seems to start at CIN I, relatively early stage of cervical cancer development. Therefore, hLHX6-HMR can be used as an effective and sensitive methylation biomarker for early diagnosis of cervical cancer.

Epigenetic silencing of the WNT antagonist DICKKOPF-1 in cervical cancer cell lines.

OBJECTIVE: Our study was designed to demonstrate that DICKKOPF-1 (DKK-1), encoding a secreted Wnt antagonist, is transcriptionally repressed by epigenetic alterations in cervical carcinoma cell lines. METHODS: Methylation-specific PCR for 8 human cervical cancer cell lines and bisulfite sequencing for 4 cell lines exhibiting significant difference in methylation levels were used to determine CpG-island methylation status at the 5'-end region of DKK-1. The chromatin immunoprecipitation assay was performed to determine whether HeLa cells recruit histone deacetylation for DKK-1 silencing. RESULTS: Two out of eight cervical cancer cell lines examined were found to be regulated by independent epigenetic inactivation mechanisms; promoter CpG hypermethylation constitutes a major epigenetic alteration in SNU-703, and histone deacetylation in HeLa cells. CONCLUSION: Our study suggests that cervical cancer cell lines exploit cell line-dependent, differential epigenetic mechanisms for DKK-1 silencing.

A new compound from Micromonospora sp. SA246, 9-hydroxycrisamicin-A, activates hepatitis B virus replication.

A new compound from Micromonospora sp. SA246, 9-hydroxycrisamicin-A (9-HCA-A), showed potential for activating hepatitis B virus (HBV) replication. To define the mechanism of 9-HCA-A, we used HepG2 2.2.15 cells which support HBV replication. 9-HCA-A activated HBV replication, increased episomal and integrated HBV DNA content, and increased secretions of HBV antigens (HBsAg and HBeAg) into culture medium. 9-HCA-A also activated HBV transcription in Hep2 2.2.15 cell line. To examine transcriptional control mechanisms, we analyzed the effect of 9-HCA-A on four different HBV promoters (Core, PreS1, PreS2, and X) in hepatoma cell line. 9-HCA-A responsive element was located at HBx promoter. By EMSA, we showed that 9-HCA-A activated the HBx promoter by detaching the 9-HCA-A responsive element binding protein (9H-REBP). Protein phosphatase (PP2A1) treatment detaches the 9H-REBP from the HBx promoter, similar to 9-HCA-A, while protein kinase A treatment does not detach the 9H-REBP from the HBx promoter. Our results showed that 9H- REBP functions as a repressor of HBV replication while 9-HCA-A activated protein phosphatase released the BP on the HBx promoter, thus activating HBV replication.