CHD5 Research Articles

Parenti–Migno neurodevelopmental disorder: a case associated with a new variant in the <i>CHD5</i> gene

Parenti–Migno neurodevelopmental disorder is a rare syndromal form of intellectual disability in children, associated with the CHD5 gene, the prevalence of which is not established. Currently, 16 patients with this pathology have been described. CHD5 belongs to the conservative family of chromatin remodeler proteins, is part of the histone deacetylase NuRD complex, and is crucial for the early differentiation of neurons in the central nervous system and acts as a tumor suppressor. Recently, thanks to the application of whole-exome sequencing, the association of this gene with Parenti–Migno neurodevelopmental disorder was first described in patients with developmental delay, psycho-neurological disturbances, facial phenotype features, and skull pathology. We present a unique case of the disease associated with a new variant p.Arg1521Thr in the CHD5 gene, in a girl with intellectual and neurological impairments, craniofacial dysmorphism, as well as previously undescribed symptoms such as cleft lip and palate, hydrocephalus, and renal pathology. The cause of the disease was determined through whole-genome sequencing, which highlights the value of this method in the diagnosis of undifferentiated forms of intellectual disabilities.

Effect of smoking on methylation and semen parameters.

One type of epigenetic modification is genomic DNA methylation, which is induced by smoking, and both are associated with male infertility. In this study, the relationship between smoking and CHD5 gene methylation and semen parameters in infertile men was determined. After the MS-PCR of blood in 224 samples, 103 infertile patients (62 smokers and 41 non-smokers) and 121 fertile men, methylation level changes between groups and the effect of methylation and smoking on infertility and semen parameters in infertile men were determined. The results showed that there is a significant difference in the methylation status (MM, MU, UU) of the CHD5 gene between the patient and the control group, and this correlation also exists for the semen parameters (p < .001). The average semen parameters in smokers decreased significantly compared to non-smokers and sperm concentration was (32.21 ± 5.27 vs. 55.27 ± 3.38), respectively. MM methylation status was higher in smokers (22.5%) compared to non-smokers (14.6%). Smoking components affect the methylation pattern of CHD5 gene, and smokers had higher methylation levels and lower semen parameters than non-smokers, which can be biomarkers for evaluating semen quality and infertility risk factors. Understanding the epigenetic effects of smoking on male infertility can be very useful for predicting negative consequences of smoking and providing therapeutic solutions.

Sifrim-Hitz-Weiss/CHD4-related syndrome: A new case report.

Sifrim-Hitz-Weiss/CHD4-related syndrome: A new case report.

ZNF410 Uniquely Activates the NuRD Component CHD4 to Silence Fetal Hemoglobin Expression

Metazoan transcription factors typically regulate large numbers of genes. Here we identify via a CRISPR-Cas9 genetic screen ZNF410, a pentadactyl DNA-binding protein that in human erythroid cells directly activates only a single gene, the NuRD component CHD4. Specificity is conveyed by two highly evolutionarily conserved clusters of ZNF410 binding sites near the CHD4 gene with no counterparts elsewhere in the genome. Loss of ZNF410 in adult-type human erythroid cell culture systems and xenotransplantation settings diminishes CHD4 levels and derepresses the fetal hemoglobin genes. While previously known to be silenced by CHD4, the fetal globin genes are exposed here as among the most sensitive to reduced CHD4 levels.. Invitro DNA binding assays and crystallographic studies reveal the ZNF410-DNA binding mode. ZNF410 is a remarkably selective transcriptional activator in erythroid cells, and its perturbation might offer new opportunities for treatment of hemoglobinopathies.

Epigallocatechin gallate induces CHD5 gene demethylation to promote acute myeloid leukemia cell apoptosis in vitro by regulating p19Arf-p53-p21Cip1 signaling pathway

To investigate the mechanism by which epigallocatechin gallate (EGCG) induces CHD5 gene demethylation and promotes the apoptosis of acute myeloid leukemia KG-1 and THP-1 cell lines. KG-1 and THP-1 cells treated with 25, 50, 75, 100 or 150 μg/mL EGCG for 48 h were examined for CHD5 gene methylation using MSP and for cell proliferation using MTT assay. The changes in cell cycle and apoptosis of the two cell lines after treatment with EGCG for 48 h were detected using flow cytometry. The mRNA and protein expressions of DNMT1, CHD5, p19Arf, p53 and p21Cip1 in the cells were detected using RT-quantitative PCR and Western blot. EGCG dose-dependently reversed hypermethylation of CHD5 gene and reduced the cell viability in both KG-1 and THP-1 cells (P < 0.05). EGCG treatment caused obvious cell cycle arrest in G1 phase, significantly increased cell apoptosis, downregulated the expression of DNMT1 and upregulated the expressions of CHD5, p19Arf, p53 and p21Cip1 in KG-1 and THP-1 cells (P < 0.05). EGCG reduces hypermethylation of CHD5 gene in KG-1 and THP-1 cells by downregulating DNMT1 to restore its expression, which results in upregulated expressions of p19Arf, p53 and p21Cip1 and induces cell apoptosis.

Methylation of CHD5 Gene Promoter Regulates p19Arf/p53/p21Cip1 Pathway to Facilitate Pathogenesis of Acute Myeloid Leukemia

To investigate the methylation status of CHD5 gene promoter in bone marrow from acute myeloid leukemia (AML) patients, and the underlying mechanism for initiating the pathogenesis of AML via p19Arf/p53/p21Cip1 pathway. Methylation status of the CHD5 gene promoter was detected by using methylation-specific polymerase chain reaction (MSPCR) in bone marrow from AML patients, and the iron-deficiency anemia (IDA) samples were served as control. The expression of CHD5, p19Arf, p53 and p21Cip1 was determined by real-time quantitative reverse transcriptase PCR and Western blot. The methylation of CHD5 gene in bone marrow from AML patients increased significantly (39.06%) as compared with control group (6.67%). The methylation of CHD5 gene significantly correlated with chromosome karyotype differentiation (P＜0.01), but did not correlate with the patient's sex, age and clinical classification (P＞0.05). The mRNA expression of CHD5 gene in AML decreased, compared with control group, the mRNA and protein expression of p19Arf, p53 and p21Cip1 in AML with CHD5 methylation promoter decreased. The hypermeltylation of CHD5 gene promoter in AML patients can lead to decrease of CHD5, p19Arf, p53 and p21Cip1 expression levels which may reduce the inhibitory effect on proliferation of leukemia cells through the regulation of p19Arf, p53 and p21Cip1 pathway, thus promotes the occurence of AML.

A rare CHD5 haplotype and its interactions with environmental factors predicting hepatocellular carcinoma risk

BackgroundCHD5 is a conventional tumour-suppressing gene in many tumours. The aim of this study was to determine whether CHD5 variants contribute to the risk of hepatocellular carcinoma (HCC).MethodsGene variants were identified using next-generation sequencing targeted on referenced mutations followed by TaqMan genotyping in two case-control studies.ResultsWe discovered a rare variant (haplotype AG) in CHD5 (rs12564469-rs9434711) that was markedly associated with the risk of HCC in a Chinese population. A logistical regression model and permutation test confirmed the association. Indeed, the association quality increased in a gene dose-dependent manner as the number of samples increased. In the stratified analysis, this haplotype risk effect was statistically significant in a subgroup of alcohol drinkers. The false-positive report probability and multifactor dimensionality reduction further supported the finding.ConclusionsOur results suggest that the rare CHD5 gene haplotype and alcohol intake contribute to the risk of HCC. Our findings can be valuable to researchers of cancer precision medicine looking to improve diagnosis and treatment of HCC.

Genetic variations in chromodomain helicase DNA-binding protein 5, gene-environment interactions and risk of sporadic Alzheimer's disease in Chinese population.

CHD5 is an essential factor for neuronal differentiation and neurodegenerative diseases. Here, the targeted next generation sequencing and TaqMan genotyping technologies were carried out for CHD5 gene in a two-staged case-control study in Chinese population. The genetic statistics and gene-environment interactions were analyzed to find certain risk factors of Alzheimer's disease. We found intronic rs11121295 was associated with the risk of Alzheimer's disease at both stages including combined cohorts. This risk effect presented consistently significant associations with the alcoholic subgroups at both all stages in the stratified analysis. The gene-environment interactions further supported the above findings. Our study highlighted the potential role of CHD5 variants in conferring susceptibility to sporadic Alzheimer's disease, especially modified its risk by alcoholic intake.

CTCF-KDM4A complex correlates with histone modifications that negatively regulate CHD5 gene expression in cancer cell lines

Histone demethylase KDM4A is involved in H3K9me3 and H3K36me3 demethylation, which are epigenetic modifications associated with gene silencing and RNA Polymerase II elongation, respectively. KDM4A is abnormally expressed in cancer, affecting the expression of multiple targets, such as the CHD5 gene. This enzyme localizes at the first intron of CHD5, and the dissociation of KDM4A increases gene expression. In vitro assays showed that KDM4A-mediated demethylation is enhanced in the presence of CTCF, suggesting that CTCF could increase its enzymatic activity in vivo, however the specific mechanism by which CTCF and KDM4A might be involved in the CHD5 gene repression is poorly understood. Here, we show that CTCF and KDM4A form a protein complex, which is recruited into the first intron of CHD5. This is related to a decrease in H3K36me3/2 histone marks and is associated with its transcriptional downregulation. Depletion of CTCF or KDM4A by siRNA, triggered the reactivation of CHD5 expression, suggesting that both proteins are involved in the negative regulation of this gene. Furthermore, the knockout of KDM4A restored the CHD5 expression and H3K36me3 and H3K36me2 histone marks. Such mechanism acts independently of CHD5 promoter DNA methylation. Our findings support a novel mechanism of epigenetic repression at the gene body that does not involve promoter silencing.

CHD5 is a potential tumor suppressor in non small cell lung cancer (NSCLC)

Lung cancer is one of the deadliest types of cancers and genetic and epigenetic alterations play major roles in its development. Chromodomain (CHD) protein family acts in chromatin organization, regulation of transcription and also genomic stability and cancer prevention. Although CHD5, a member of this family was shown to contribute to major cellular events and functions as a tumor suppressor gene in various types of cancer, it is not clear whether CHD5 plays a role in lung carcinogenesis. The aim of this study was to investigate the possible role of CHD5 in progression of non-small cell lung cancer (NSCLC). Expression levels of CHD5 gene in 59 tumor and corresponding non-cancerous lung tissue samples were analyzed by qRT-PCR and the methylation status of the promoter region was investigated by methylation specific PCR (MS-PCR). The Akt phosphorylation levels were investigated by Western Blot (WB). CHD5 was down-regulated in 17 (39.5%) and up-regulated in 24 (55.8%) of tumor specimens. Even though the promoter of CHD5 was hypermethylated in 8 patients, it was not found associated with CHD5 gene expression (p=0.08). Akt phosphorylation was increased in 14 (53.8%) and decreased in 12 (46.2%) of the samples but no significant association was found between p-Akt phosphorylation and CHD5 expression (p=0.67). We suggest that CHD5 may act as a tumor suppressor gene in NSCLC.

Decreased expression of the CHD5 gene and its clinicopathological significance in breast cancer: Correlation with aberrant DNA methylation.

Chromodomain helicase DNA binding protein 5 (CHD5) has been identified as a tumor suppressor in mouse models. Downregulation of CHD5 gene expression is frequently observed in breast cancer cells and tissues. This may be explained by deletions or other mutations; however, alternative mechanisms require investigation. Therefore, the present study evaluated whether CHD5 aberrant methylation has a role in primary breast tumors. A total of 389 patients with primary breast cancer (including 252 paraffin-embedded specimens and 137 fresh-frozen samples) were enrolled in the present study. In the current study, reverse transcription-polymerase chain reaction (RT-PCR) and nested-methylation-specific PCR were used to analyze the mRNA expression and promoter methylation of CHD5 genes in a large cohort of breast cancer patients, and to investigate their associations with the clinicopathological features of tumors. CHD5 expression was significantly suppressed in breast cancer tissues compared with normal breast tissues when analyzed by RT-PCR. Furthermore, DNA methylation of CHD5 was more prevalent in breast tumors than in normal tissues. CHD5 mRNA levels correlated with the degree of CHD5 methylation in breast cancer tissues. Clinicopathological correlation analysis revealed that CHD5 promoter methylation was associated with estrogen receptor and progesterone receptor status. Thus, downregulation of CHD5, mediated by abnormal methylation, may contribute to the development and progression of breast cancer.

Abstract 2433: Loss of chd5-mediated gene repression synergizes with MYCN to accelerate neuroblastoma tumorigenesis in zebrafish

Abstract Neuroblastoma is a malignancy of the peripheral sympathetic nervous system (PSNS) and accounts for 10-15% of cancer deaths among children. For the 40% of patients presenting with high-risk disease, current therapeutic approaches are insufficient and long-term survival is less than 50%. Along with genomic amplification of the MYCN oncogene, hemizygous loss of the 1p36 chromosomal region is a major risk factor in neuroblastoma. The human CHD5 gene is a neuronal specific chromatin remodeling helicase that maps to 1p36, and is thus frequently lost in high-risk neuroblastoma. Our laboratory has previously generated a faithful model of pediatric neuroblastoma in the zebrafish driven by overexpression of the MYCN oncogene in the PSNS (dbh:MYCN). Additionally, zebrafish chd5 mutant alleles were created using the newly developed gene editing technologies TALEN and CRISPR-Cas9. The resulting chd5 mutant fish exhibit abnormal development of the PSNS in the form of expansion of the superior cervical ganglia and enlargement of the interrenal gland (adrenal medulla). Haploinsufficiency for Chd5 combined with dbh:MYCN expression accelerates the onset and increases the penetrance of neuroblastoma tumorigenesis in zebrafish, indicating a tumor suppressive function. Elevated p-ERK and PCNA+ cells in tumor tissue indicates that loss of Chd5, cooperates with MYCN overexpression to accelerate neuroblast proliferation in vivo. Chd5 (in addition to Chd3 and Chd4) is a core member of the epigenetic regulatory NuRD complex, which also contains HDAC1-2, MTA1-3, MBD2-3, GATAD2A/B and RBBP4/7. The conserved biological function of Chd5 is to silence gene expression through the maintenance of a repressed chromatin state. Tumors deficient for Chd5 expression exhibit reduced levels of the H3K27me3 histone modification, a marker of facultatively repressed genes. Future studies will further explore the mechanism and function of Chd5 so that the pathways mediating tumor suppression can be elucidated and that essential proteins in these pathways can be targeted in ways that exploit the synthetic lethal relationships that are established. Citation Format: Mark W. Zimmerman, Shuning He, Jimann Shin, Shizhen Zhu, Feng Guo, Marc Mansour, Deepak Reyon, J Keith Joung, Jinhua Quan, Timur Yusufzai, A Thomas Look. Loss of chd5-mediated gene repression synergizes with MYCN to accelerate neuroblastoma tumorigenesis in zebrafish. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2433.

Defeating EpCAM+ liver cancer stem cells by targeting chromatin remodeling enzyme CHD4 in human hepatocellular carcinoma

Hepatocellular carcinoma is composed of a subset of cells with enhanced tumorigenicity and chemoresistance that are called cancer stem (or stem-like) cells. We explored the role of chromodomain-helicase-DNA-binding protein 4, which is encoded by the CHD4 gene and is known to epigenetically control gene regulation and DNA damage responses in EpCAM(+) liver cancer stem cells. Gene and protein expression profiles were determined by microarray and immunohistochemistry in 245 and 144 hepatocellular carcinoma patients, respectively. The relationship between gene/protein expression and prognosis was examined. The functional role of CHD4 was evaluated in primary hepatocellular carcinoma cells and in cell lines in vitro and in vivo. CHD4 was abundantly expressed in EpCAM(+) hepatocellular carcinoma with expression of hepatic stem cell markers and poor prognosis in two independent cohorts. In cell lines, CHD4 knockdown increased chemosensitivity and CHD4 overexpression induced epirubicin chemoresistance. To inhibit the functions of CHD4 that are mediated through histone deacetylase and poly (ADP-ribose) polymerase, we evaluated the effect of the histone deacetylase inhibitor suberohydroxamic acid and the poly (ADP-ribose) polymerase inhibitor AG-014699. Treatment with either suberohydroxamic acid or AG-014699 reduced the number of EpCAM(+) liver cancer stem cells in vitro, and suberohydroxamic acid and AG-014699 in combination successfully inhibited tumor growth in a mouse xenograft model. CHD4 plays a pivotal role in chemoresistance and the maintenance of stemness in liver cancer stem cells and is therefore a good target for the eradication of hepatocellular carcinoma.

Targeting p53 in CML Chronic Phase Leukemia Stem Cells

Chronic myelogenous leukemia (CML) is a hematological disease resulting from generation of BCR/ABL oncogene. Resveratrol is an important phytoalexin which is contained in many plants and it has cytotoxic effects in various cancer types. Gene promoter methylation causes loss of tumor suppressor gene function in human cancer. CHD4 (Chromodomain/Helicase/DNAbinding domain) gene which contains a CpG island is a member of the cadherin family. In this study we aimed to evaluate the role of epigenetic modification of resveratrol in cadherin family genes in K562 human CML cell line. K562 cells were treated with 100 mM (IC50 dose) resveratrol depend on time and dosage during 72 hours and cytotoxicity was evaluated by using WST-1 assay. The RT-qPCR is used for gene expression analysis. Gene expression levels were evaluated by using RT Profiler PCR Array. RT-qPCR results showed that, CHD4 gene expression increased 3.45 fold, according to the control cells that untreated with resveratrol. Significant upregulation was found in CHD4 gene expression among the cadherin family genes in resveratrol treated K562 cells. CHD4 is affected by methylation and frequently is silenced in CML. Downregulation of CHD4 gene expression could trigger activation of the Wnt-pathway and cause aberant cell-to-cell interactions. After treatment with the resveratrol in K562 cells, CHD4 gene expression was upregulated. Resveratrol could increase the cadherin family gene expressions and activation of the Wntpathway is blocked in CML. Also, resveratrol could demethylate CpG island in CHD4 promoter region and increase CHD4 gene expression. Our results indicate that resveratrol may act as a demethylation agent on the promoter of tumor supresor genes such as CHD4 and increase the expression of these genes. Therefore, resveratrol could be used as a pioneering anti-tumorigenesis drug in CML. 411 Targeting p53 in CML Chronic Phase Leukemia Stem Cells Luke F. Peterson, Miao-Chia Lo, Yihong Lui, Diane Gianolla, Emilija Mitrikeska, Nicholas J. Donato, Craig N. Johnson, Shaomeng Wang, Jessica Mercer, Moshe Talpaz Comprehensive Cancer Center, University of Michigan, Ann Arbor, MI, USA; Division of Hematology and Oncology, Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA; Moores UCSD Cancer Center, University of California San Diego, La Jolla, CA, USA; DNA Sequencing and Microarray Core, University of Michigan, Ann Arbor, MI, USA; Department of Pharmacology and Medicinal Chemistry, University of Michigan, Ann Arbor, MI, USA

Resveratrol Increases CHD4 Gene Expression and Regulates Wnt Signaling in Chronic Myeloid Leukemia

Chronic myelogenous leukemia (CML) is a hematological disease resulting from generation of BCR/ABL oncogene. Resveratrol is an important phytoalexin which is contained in many plants and it has cytotoxic effects in various cancer types. Gene promoter methylation causes loss of tumor suppressor gene function in human cancer. CHD4 (Chromodomain/Helicase/DNA- binding domain) gene which contains a CpG island is a member of the cadherin family. In this study we aimed to evaluate the role of epigenetic modification of resveratrol in cadherin family genes in K562 human CML cell line. K562 cells were treated with 100 mM (IC50 dose) resveratrol depend on time and dosage during 72 hours and cytotoxicity was evaluated by using WST-1 assay. The RT-qPCR is used for gene expression analysis. Gene expression levels were evaluated by using RT 2 Profiler PCR Array. RT-qPCR results showed that, CHD4 gene expression increased 3.45 fold, according to the control cells that untreated with resveratrol. Significant upregulation was found in CHD4 gene expression among the cadherin family genes in resveratrol treated K562 cells. CHD4 is affected by methylation and frequently is silenced in CML. Downregulation of CHD4 gene expression could trigger activation of the Wnt-pathway and cause aberant cell-to-cell interactions. After treatment with the resveratrol in K562 cells, CHD4 gene expression was upregulated. Resveratrol could increase the cadherin family gene expressions and activation of the Wntpathway is blocked in CML. Also, resveratrol could demethylate CpG island in CHD4 promoter region and increase CHD4 gene expression. Our results indicate that resveratrol may act as a demethylation agent on the promoter of tumor supresor genes such as CHD4 and increase the expression of these genes. Therefore, resveratrol could be used as a pioneering anti-tumorigenesis drug in CML.

CHD5 a tumour suppressor is epigenetically silenced in hepatocellular carcinoma

Chromodomain helicase DNA binding protein 5 (CHD5) has recently been identified as a potent tumour suppressor by acting as a master regulator of a tumour-suppressive network. Its inactivation resulted from aberrant methylation in the promoter occurs in several types of human malignancy and is associated with malignant tumour behaviour. In human hepatocellular carcinoma (HCC), CHD5 gene expression, methylation status and tumour-suppressive function have not been elucidated. In this study, we focused on the epigenetic modification and tumour-suppressive mechanism of CHD5 gene in HCC. CHD5 expression in nine HCC cell lines and 30 pairs of HCC specimens and adjacent non-cancerous tissues were analysed by quantitative reverse transcription PCR and Western blotting. Methylation-specific sequencing and methylation-specific PCR were performed to examine DNA methylation status of the CHD5 promoter in HCC cell lines and samples. The effect of CHD5 restoration on proliferation, colony formation, senescence, apoptosis and tumourigenicity were examined. CHD5 expression was sinificantly down-regulated in HCC cell lines and tissues examined, and the -841 to -470 region of CHD5 promoter was hypermethylated in these samples. Treatment with DNA methyltransferase inhibitor 5-aza-2-deoxycytidine resulted in a striking regional demethylation of the -841 to -470 region of CHD5 promoter and an increase in CHD5 expression. The restoration of CHD5 expression inhibited tumour cell proliferation, colony formation and tumourigenicity and caused cellular senescence. Our findings demonstrate that CHD5 is a potential tumour suppressor gene epigenetically silenced in HCC.

Silencing of CHD5 Gene by Promoter Methylation in Leukemia

Chromodomain helicase DNA binding protein 5 (CHD5) was previously proposed to function as a potent tumor suppressor by acting as a master regulator of a tumor-suppressive network. CHD5 is down-regulated in several cancers, including leukemia and is responsible for tumor generation and progression. However, the mechanism of CHD5 down-regulation in leukemia is largely unknown. In this study, quantitative reverse-transcriptase polymerase chain reaction and western blotting analyses revealed that CHD5 was down-regulated in human leukemia cell lines and samples. Luciferase reporter assays showed that most of the baseline regulatory activity was localized from 500 to 200 bp upstream of the transcription start site. Bisulfite DNA sequencing of the identified regulatory element revealed that the CHD5 promoter was hypermethylated in human leukemia cells and samples. Thus, CHD5 expression was inversely correlated with promoter DNA methylation in these samples. Treatment with DNA methyltransferase inhibitor 5-aza-2′-deoxycytidine (DAC) activates CHD5 expression in human leukemia cell lines. In vitro luciferase reporter assays demonstrated that methylation of the CHD5 promoter repressed its promoter activity. Furthermore, a chromatin immunoprecipitation assay combined with qualitative PCR identified activating protein 2 (AP2) as a potential transcription factor involved in CHD5 expression and indicated that treatment with DAC increases the recruitment of AP2 to the CHD5 promoter. In vitro transcription-factor activity studies showed that AP2 over-expression was able to activate CHD5 promoter activity. Our findings indicate that repression of CHD5 gene expression in human leukemia is mediated in part by DNA methylation of its promoter.

Epigenetic silencing of CHD5, a novel tumor‐suppressor gene, occurs in early colorectal cancer stages

Chromodomain helicase DNA binding protein 5 (CHD5) is a family member of chromatin remodeling factors. The epigenetic silencing mechanisms of CHD5 in colorectal cancer have not been well studied. Here we analyzed CHD5 methylation and mRNA expression in vitro and in clinical samples from African American patients. DNA and RNA were isolated from formalin fixed paraffin embedded (FFPE) colon tissues. DNA was tested for methylation using methylation-specific polymerase chain reation (PCR) and bisulfite sequencing. RNA was used for mRNA quantification using qRT-PCR. The RKO cell line was treated with 5-Aza-dC and SAHA. RKO cells were also stably transfected with a CHD5-expressing vector. The transcriptional activity was studied in the 1 kb upstream region of the CHD5 promoter using the dual reporter assay. We performed cell proliferation, migration, and invasion assays using the RKO cell line. In most adenoma samples, CHD5 expression was not detected in contrast to normal tissues. In RKO cells, CHD5 silencing was associated with DNA methylation and repressive histone modifications. CHD5 expression was restored after treatment with 5-Aza-dC and SAHA. CHD5 reactivation reduced cell proliferation, migration, and invasion. The reporter assay indicated that the main regulatory region of the CHD5 promoter is encompassed in the -489 to -823 region with important transcriptional regulatory sites (TCF/LEF, SP1, and AP-2). The CHD5 gene is repressed in all types of adenomas, either epigenetically or by chromosomal deletion. CHD5 activity is regulated by DNA methylation and repressive histone modifications. CHD5 likely acts as a tumor-suppressor gene in early colorectal carcinogenesis.

Analysis of common variations in tumor-suppressor genes on chr1p36 among Caucasian women with endometriosis

ObjectiveEpidemiological data indicate that endometriosis increases the risk of epithelial ovarian cancer (EOC), but the mechanism of cancer transition is unknown. Results from genome-wide association studies (GWAS) and transcriptome sequencing have demonstrated that genes located in the 1p36 region are important in both endometriosis and endometriosis-associated cancer development. Therefore, we tested the hypothesis that SNPs in two tumor-suppressor genes (CHD5 and ARID1A) in the 1p36 region are associated with endometriosis. MethodsAllele frequencies of SNPs were investigated in 1685 Caucasian women consisting of 947 women with endometriosis and 738 controls. Peripheral blood samples were retrieved, DNA extracted and allelic frequencies of SNPs in two tumor-suppressor genes (CHD5 and ARID1A) were analyzed using TaqMan Open Array technique. ResultsAssociations were observed for 3 SNPs in the CHD5 gene: rs1883603 (OR 1.31, 95% CI 1.00–1.71), rs9434741 (OR 1.41, 95% CI 1.16–1.71) and rs17436816 (OR 1.24, 95% CI 1.02–1.50). After correction for multiple comparisons, rs9434741 (CHD5) remained significantly associated with endometriosis (p<0.01). No associations were detected for ARID1A. ConclusionsIn this Caucasian population, endometriosis seems to be associated with the tumor-suppressor gene CHD5. Our findings support recent data, suggesting that the 1p36 region plays an important role in endometrios. To validate these data, replication in an independent population is warranted.

CHD5 Downregulation Associated with Poor Prognosis in Epithelial Ovarian Cancer

Background: The CHD5 gene located on 1p36 encodes a protein – chromodomain helicase DNA-binding protein 5. CHD5 has been shown to be a tumor suppressor gene candidate. This study investigated the involvement of CHD5 in ovarian cancer and its clinicopathological significance. Methods: CHD5 expression in ovarian cancer and its counterpart were determined by quantitative RT-PCR. The correlation of CHD5 expression to clinicopathological features of the tumor was analyzed. Results: CHD5 expression was downregulated by at least twofold in 32 of 72 (41%) invasive epithelial ovarian carcinomas when compared to 12 controls in Hong Kong Chinese women. CHD5 downregulation was correlated to clinical status (p < 0.05), but not to patient age, tumor type and grade, recurrence and clinical stage (p > 0.05). Survival analysis showed that patients with CHD5 downregulation in their tumors were associated with shorter disease-free and total survival times compared to those without CHD5 downregulation (p < 0.05). Cox proportional-hazards regression analysis indicated that downregulation of CHD5 is an independent adverse prognostic factor in ovarian cancer. Conclusion: This study shows that CHD5 is downregulated in a certain number of ovarian cancers and appears to be an adverse predictor candidate of ovarian cancer disease-free and total survival.