RARβ Gene Research Articles

DNA methylation and gene deletion analysis of brain metastases in melanoma patients identifies mutually exclusive molecular alterations.

The brain is a common target of metastases for melanoma patients. Little is known about the genetic and epigenetic alterations in melanoma brain metastases (MBMs). Unraveling these molecular alterations is a key step in understanding their aggressive nature and identifying novel therapeutic targets. Genome-wide DNA methylation analyses of MBMs (n = 15) and normal brain tissues (n = 91) and simultaneous multigene DNA methylation and gene deletion analyses of metastatic melanoma tissues (99 MBMs and 43 extracranial metastases) were performed. BRAF and NRAS mutations were evaluated in MBMs by targeted sequencing. MBMs showed significant epigenetic heterogeneity. RARB, RASSF1, ESR1, APC, PTEN, and CDH13 genes were frequently hypermethylated. Deletions were frequently detected in the CDKN2A/B locus. Of MBMs, 46.1% and 28.8% had BRAF and NRAS missense mutations, respectively. Compared with lung and liver metastases, MBMs exhibited higher frequency of CDH13 hypermethylation and CDKN2A/B locus deletion. Mutual exclusivity between hypermethylated genes and CDKN2A/B locus deletion identified 2 clinically relevant molecular subtypes of MBMs. CDKN2A/B deletions were associated with multiple MBMs and frequently hypermethylated genes with shorter time to brain metastasis. Melanoma cells that colonize the brain harbor numerous genetically and epigenetically altered genes. This study presents an integrated genomic and epigenomic analysis that reveals MBM-specific molecular alterations and mutually exclusive molecular subtypes.

Associations between single nucleotide polymorphisms in cellular viral receptors and attachment factor-related genes and humoral immunity to rubella vaccination.

BackgroundViral attachment and cell entry host factors are important for viral replication, pathogenesis, and the generation and sustenance of immune responses after infection and/or vaccination, and are plausible genetic regulators of vaccine-induced immunity.MethodsUsing a tag-SNP approach in candidate gene study, we assessed the role of selected cell surface receptor genes, attachment factor-related genes, along with other immune genes in the genetic control of immune response variations after live rubella vaccination in two independent study cohorts.ResultsOur analysis revealed evidence for multiple associations between genetic variants in the PVR, PVRL2, CD209/DC-SIGN, RARB, MOG, IL6 and other immune function-related genes and rubella-specific neutralizing antibodies after vaccination (meta p-value <0.05).ConclusionOur results indicate that multiple SNPs from genes involved in cell adhesion, viral attachment, and viral entry, as well as others in genes involved in signaling and/or immune response regulation, play a role in modulating humoral immune responses following live rubella vaccination.

Epigenetic alteration of p16 and retinoic acid receptor beta genes in the development of epithelial ovarian carcinoma.

Silencing of tumor suppressor and tumor-related genes by promoter hypermethylation is one of the major events in ovarian carcinogenesis. In this study, we analyzed aberrant promoter methylation of p16 and RAR-β genes in 134 epithelial ovarian carcinomas (EOCs), 23 low malignant potential (LMP) tumors, 26 benign cystadenomas, and 15 normal ovarian tissues. Methylation was investigated by methylation-specific PCR (MSP), and the results were confirmed by bisulfite DNA sequencing. Relative gene expression of p16 and RAR-β was done using quantitative reverse transcriptase PCR (qRT-PCR) on 51 EOC cases, 9 LMP tumors, and 7 benign cystadenomas with 5 normal ovarian tissues. Aberrant methylation for p16 and RAR-β was present in 43 % (58/134) and 31 % (41/134) in carcinoma cases, 22 % (05/23) and 52 % (12/23) in LMP tumors, and 42 % (11/26) and 69 % (18/26) in benign cystadenomas. No methylation was observed in any of the normal ovarian tissues. The mRNA expression level of p16 and RAR-β was significantly downregulated in EOC and LMP tumors than the corresponding normal tissues whereas the expression level was normal in benign cystadenomas for p16 and slightly reduced for RAR-β. A significant correlation of p16 promoter methylation was observed with reduced gene expression in EOC. For RAR-β, no significant correlation was observed between promoter methylation and gene expression. Our results suggest that epigenetic alterations of p16 and RAR-β have an important role in ovarian carcinogenesis and that mechanism along with methylation plays a significant role in downregulation of RAR-β gene in ovarian cancer.

Prostaglandin E2 induces retinoic acid receptor-β up-regulation through MSK1

The pharmacological modulation of putative renoprotective factors hypoxia-inducible factor-1α (HIF-1α) and HIF-1α-regulated vascular endothelial growth factor-A (VEGF-A) in the kidney has therapeutic interest. In human renal proximal tubular HK2 cells, prostaglandin E2 (PGE2) up-regulates HIF-1α and VEGF-A through epidermal growth factor receptor (EGFR)-dependent up-regulation of retinoic acid receptor-β (RARβ). Here we studied the role of mitogen-activated protein kinases (MAPKs) ERK1/2 and p38 and their target kinase, mitogen- and stress activated kinase-1 (MSK1), in the signaling cascade. Treatment of HK2 cells with PGE2 resulted in increased phosphorylation of EGFR, the three studied kinases and the histone H3 (Ser10) at the RARβ gene promoter (the latter has been proposed as a molecular signature of the activated RARβ gene promoter). Prevention of the phosphorylation of EGFR, ERK1/2, p38 MAPK or MSK1 is by incubating, respectively, with AG1478, PD98059, SB203580 or H89 allowed to elucidate the precise phosphorylation order in the signaling cascade triggered by PGE2: first, EGFR; then, ERK1/2 and p38 MAPK and, finally, MSK1. Phosphorylation of MSK1 led to that of Ser10 in histone H3 and to activation of RARβ gene transcription (and the consequent increase in the expression of HIF-1α and VEGF-A), which was suppressed by H89 or by transfecting cells with a vector encoding for a dominant-negative mutant of MSK1. These results highlight the relevance of MSK1 in the up-regulation of RARβ by PGE2. They also may contribute to new therapeutic approaches based upon the pharmacological control of HIF-1α/VEGF-A in the proximal tubule through the modulation of the PGE2/EGFR/MAPK/MSK1/RARβ pathway.

All-trans retinoic acid enhances the effect of 5-aza-2'-deoxycytidine on p16INK4a demethylation, and the two drugs synergistically activate retinoic acid receptor β gene expression in the human erythroleukemia K562 cell line.

The aim of the current study was to investigate the antineoplastic activities of 5-aza-2′-deoxycytidine (also known as decitabine; DAC) and all-trans retinoic acid (ATRA), administered alone or in combination, in K562 cells in vitro, as well as the effects on the expression of the tumor suppressor genes, p16INK4a (p16) and retinoic acid receptor β (RAR-β). Cell growth inhibition, differentiation and apoptosis in K562 cells treated with DAC and/or ATRA were detected. The methylation of the p16 and RAR-β genes in the K562 cells was detected using the methylation-specific polymerase chain reaction (PCR) method. Quantitative PCR was used for the detection of the mRNA expression of the p16 and RAR-β genes, and western blot analysis was used to detect protein expression. DAC and ATRA, alone or in combination, had no effect on the growth inhibition, differentiation and apoptosis of the K562 cells. DAC alone induced the demethylation of the p16 gene, and combination of DAC and ATRA demonstrated more evident demethylation of the p16 gene, however, ATRA alone had no effect on methylation. The RAR-β promoter region was not methylated in the K562 cells. DAC in combination with ATRA appeared to produce a greater activation of the RAR-β gene, which led to the upregulation of the RAR-β expression level. ATRA enhanced the effect of DAC on p16 demethylation, and the combination of the two drugs was found to activate RAR-β expression, which indicated that DAC used in combination with ATRA has clinical potential in the treatment of human erythroleukemia.

A meta-analysis of the relationship between RARβ gene promoter methylation and non-small cell lung cancer.

BackgroundHypermethylation of CpG islands in tumor suppressor gene plays an important role in carcinogenesis. Many studies have demonstrated that hypermethylation in promoter region of RARβ gene could be found with high prevalence in tumor tissue and autologous controls such as corresponding non-tumor lung tissue, sputum and plasma of the NSCLC patients. But with the small number subjects included in the individual studie, the statistical power is limited. Accordingly, we performed this meta-analysis to further asses the relationship of methylation prevalence between the cancer tissue and atuologous controls (corresponding non-tumor lung tissue, sputum and plasma).MethodsThe published articles about RARβ gene promoter hypermethyltion were identified using a systematic search strategy in PubMed, EMBASE and CNKI databases. The pooled odds ratio (OR) of RARβ promoter methylation in lung cancer tissue versus autologous controls were calculated.ResultsFinally, eleven articles, including 1347 tumor tissue samples and 1137 autologous controls were included in this meta-analysis. The pooled odds ratio of RARβ promoter methylation in cancer tissue was 3.60 (95%CI: 2.46–5.27) compared to autologous controls with random-effect model. Strong and significant correlation between tumor tissue and autologous controls of RARβ gene promoter hypermethylation prevalence across studies (Correlation coefficient 0.53) was found.Conclusion RARβ promoter methylation may play an important role in carcinogenesis of the NSCLC. With significant methylation prevalence correlation between tumor tissue and autologous of this gene, methylation detection may be a potential method for searching biomarker for NSCLC.

Retinoic acid reduces migration of human breast cancer cells: role of retinoic acid receptor beta

Breast cancer is the most common malignancy in women and the appearance of distant metastases produces the death in 98% of cases. The retinoic acid receptor β (RARβ) is not expressed in 50% of invasive breast carcinoma compared with normal tissue and it has been associated with lymph node metastasis. Our hypothesis is that RARβ protein participates in the metastatic process. T47D and MCF7 breast cancer cell lines were used to perform viability assay, immunobloting, migration assays, RNA interference and immunofluorescence. Administration of retinoic acid (RA) in breast cancer cells induced RARβ gene expression that was greatest after 72 hrs with a concentration 1 μM. High concentrations of RA increased the expression of RARβ causing an inhibition of the 60% in cell migration and significantly decreased the expression of migration-related proteins [moesin, c-Src and focal adhesion kinase (FAK)]. The treatment with RARα and RARγ agonists did not affect the cell migration. On the contrary, the addition of the selective retinoid RARβ-agonist (BMS453) significantly reduced cell migration comparable to RA inhibition. When RARβ gene silencing was performed, the RA failed to significantly inhibit migration and resulted ineffective to reduce moesin, c-Src and FAK expressions. RARβ is necessary to inhibit migration induced by RA in breast cancer cells modulating the expression of proteins involved in cell migration.

Epigenetic changes during hematopoietic cell granulocytic differentiation – comparative analysis of primary CD34+ cells, KG1 myeloid cells and mature neutrophils

BackgroundEpigenetic regulation is known to affect gene expression, and recent research shows that aberrant DNA methylation patterning and histone modifications may play a role in leukemogenesis. In order to highlight the co-operation of epigenetic mechanisms acting during the latter process it is important to clarify their potential as biomarkers of granulocytic differentiation.ResultsIn this study we investigated epigenetic alterations in human hematopoietic cells at a distinct differentiation stages: primary hematopoietic CD34+ cells, KG1 myeloid leukemic cells, whose development is stopped at early stage of differentiation, and mature neutrophils. We focused on the epigenetic status of cell cycle regulating (p15, p16) and differentiation related (E-cadherin and RARβ) genes. We found that the methylation level in promoter regions of some of these genes was considerably higher in KG1 cells and lower in CD34+ cells and human neutrophils. As examined and evaluated by computer-assisted methods, histone H3 and H4 modifications, i.e. H3K4Me3, H3K9Ac, H3K9Ac/S10Ph and H4 hyperAc, were similar in CD34+ cells and human mature neutrophils. By contrast, in the KG1 cells, histone H3 and H4 modifications were quite high and increased after induction of granulocytic differentiation with the HDAC inhibitor phenyl butyrate.ConclusionsWe found the methylation status of the examined gene promoters and histone modifications to be characteristically associated with the hematopoietic cell progenitor state, induced to differentiate myeloid KG1 cells and normal blood neutrophils. This could be achieved through epigenetic regulation of E-cadherin, p15, p16 and RARβ genes expression caused by DNA methylation/demethylation, core and linker histones distribution in stem hematopoietic cells, induced to differentiation KG1 cells and mature human neutrophils, as well as the histone modifications H3K4Me3, H3K9Ac, H3K9Ac/S10Ph and H4 hyperAc in relation to hematopoietic cell differentiation to granulocyte. These findings also suggest them as potentially important biomarkers of hematopoietic cell granulocytic differentiation and could be valuable for leukemia induced differentiation therapy.

Demethylation of RARβ2 Gene Promoter by Withania somnifera in HeLa Cell Line

An important molecular target for cancer therapy is the possible reactivation of tumor suppressor genes that have been silenced by promoter methylation. It was observed that the treatment of an adenocarcinoma cervical cancer cell line, HeLa with 20 μg/ml of the ethanolic extract of Withania somnifera for 6 days resulted in demethylation of promoter of RARβ2 gene. However, treatment with Ocimum sanctum and Azadirachta indica (20μg/ml) did not cause the reversal of hypermethylation after 6 days of treatment. This is the first report to show the reversal of hypermethylation of RARβ2 gene by Withania somnifera extract in a cervical cancer cell line.

Epigenetic Priming of AML Blasts for All-trans Retinoic Acid-Induced Differentiation by the HDAC Class-I Selective Inhibitor Entinostat

All-trans retinoic acid (ATRA) has only limited single agent activity in AML without the PML-RARα fusion (non-M3 AML). In search of a sensitizing strategy to overcome this relative ATRA resistance, we investigated the potency of the HDAC class-I selective inhibitor entinostat in AML cell lines Kasumi-1 and HL-60 and primary AML blasts. Entinostat alone induced robust differentiation of both cell lines, which was enhanced by the combination with ATRA. This “priming” effect on ATRA-induced differentiation was at least equivalent to that achieved with the DNA hypomethylating agent decitabine, and could overall be recapitulated in primary AML blasts treated ex vivo. Moreover, entinostat treatment established the activating chromatin marks acH3, acH3K9, acH4 and H3K4me3 at the promoter of the RARβ2 gene, an essential mediator of retinoic acid (RA) signaling in different solid tumor models. Similarly, RARβ2 promoter hypermethylation (which in primary blasts from 90 AML/MDS patients was surprisingly infrequent) could be partially reversed by decitabine in the two cell lines. Re-induction of the epigenetically silenced RARβ2 gene was achieved only when entinostat or decitabine were given prior to ATRA treatment. Thus in this model, reactivation of RARβ2 was not necessarily required for the differentiation effect, and pharmacological RARβ2 promoter demethylation may be a bystander phenomenon rather than an essential prerequisite for the cellular effects of decitabine when combined with ATRA. In conclusion, as a “priming” agent for non-M3 AML blasts to the differentiation-inducing effects of ATRA, entinostat is at least as active as decitabine, and both act in part independently from RARβ2. Further investigation of this treatment combination in non-M3 AML patients is therefore warranted, independently of RARβ2 gene silencing by DNA methylation.

Gene methylation in rectal cancer: Predictive marker of response to chemoradiotherapy?

Although numerous studies have focused on the link between CpG island methylator phenotypes and the development of colorectal cancer, few studies have dealt specifically with methylation profiling in rectal cancer and its role in predicting response to neoadjuvant chemoradiotherapy (NCRT). We characterized methylation profiles in normal and neoplastic tissue samples from patients with rectal cancer and assessed the role of this molecular profile in predicting chemoradioactivity. We evaluated 74 pretreatment tumor samples and 16 apparently normal tissue biopsies from rectal cancer patients submitted to NCRT. The methylation profile of 24 different tumor suppressor genes was analyzed from FFPE samples by methylation-specific multiplex ligation-dependent probe amplification (MS-MLPA). Methylation status was studied in relation to tissue type and clinical pathological parameters, in particular, pathological response evaluated by tumor regression grade (TRG). ESR1, CDH13, RARB, IGSF4, and APC genes showed high methylation levels in tumor samples (range 18.92-49.77) with respect to normal tissue. Methylation levels of the remaining genes were low and similar in both normal (range 1.91-14.56) and tumor tissue (range 1.84-11). Analysis of the association between methylation and response to therapy in tumor samples showed that only TIMP3 methylation status differed significantly within the four TRG classes (ANOVA, P < 0.05). Results from the present explorative study suggest that quantitative epigenetic classification of rectal cancer by MS-MLPA clearly distinguishes tumor tissue from apparently normal mucosa. Conversely, with the exception of TIMP3 gene, the methylation of selected genes does not seem to correlate with response to NCRT.

Directionality of noncoding human RNAs: How to avoid artifacts

Inactivation of tumor suppressor and metastasis suppressor genes via epigenetic silencing is a frequent event in human cancers. Recent work has shown new mechanisms of epigenetic silencing, based on the occurrence of long noncoding promoter-spanning antisense and/or sense RNAs (lncRNAs), which constitute part of chromatin silencing complexes. Using reverse transcription polymerase chain reaction (RT–PCR), we have started to scan “triple negative” and Her2-overexpressing breast cancer cell lines for directional/bidirectional transcription through promoters of tumor suppressor and metastasis suppressor genes known to be epigenetically silenced in vivo. Surprisingly, we found that RT–PCR-amplified products were obtained at high frequency in the absence of exogenous primers. These amplified products resulted from RT priming via transcripts originating from promoter or upstream spanning regions. Consequently, this priming overruled directionality determination and led to false detection–identification of such lncRNAs. We show that this prevalent “no primer” artifact can be eliminated by treating the RNA preparations with periodate, performing RT reactions at highly elevated temperatures, or a combination of both. These experimental improvements enabled determination of the presence and directionality of individual promoter-spanning long noncoding RNAs with certainty. Examples for the BRMS1 metastasis suppressor gene, as well as RAR-β2 and CST6 human tumor suppressor genes, in breast carcinoma cell lines are presented.

Methylation of the RARB Gene Increases Prostate Cancer Risk in Black Americans

Gene promoter hypermethylation may be useful as a biomarker for cancer risk in histopathologically benign prostate specimens. We performed a nested case-control study of gene promoter methylation status for 5 genes (APC, RARB, CCND2, RASSF1 and MGMT) measured in benign biopsy specimens from 511 prostate cancer case-control pairs. We estimated the overall and race stratified risk of subsequent prostate cancer associated with methylation status. On race stratified analysis RARB methylation was associated with a higher cancer risk in black American men (OR 2.18, 95% CI 1.39-3.44). APC methylation was associated with an increased risk of high grade tumors (OR 2.43, 95% CI 1.20-4.90), which was higher in black than in white men (OR 3.21 vs 2.04). In cases RARB and APC gene methylation in benign prostate samples persisted in matched malignant specimens. In black cases the combined risk associated with RARB and APC methylation (OR 3.04, 95% CI 1.44-6.42) was greater than the individual risk of each gene and significantly different from that in white cases (OR 1.14, 95% CI 0.56-2.30). RARB gene methylation in histopathologically benign prostate samples was associated with a statistically significant increased risk of subsequent prostate cancer in black men. Methylation data on additional genes may improve risk stratification and clinical decision making algorithms for cancer screening and diagnosis.

Efficacy of Bisulfite Modification and DNA Recovery Using Commercial Kits from Samples of Genomic and Circulating DNA

This study had evaluated three commercially available bisulfite modification kits with regard to the procedural DNA loss and the efficacy of cytosine conversion to uracil. The efficacy of DNA conversion was estimated by pyrosequencing of eight CpG sites of unmethylated and fully enzymatically methylated templates of RARβ gene promoter region and cirDNAs of healthy donors and prostate cancer patients. The procedural DNA loss was calculated by methyl-independent qPCR for ubiquitously distributed L1RE1 retrotransposable elements. Our data demonstrates that all commercial kits displayed similar conversion efficacy of the unmethylated cytosines close to 99% independently of DNA concentration. However, when low DNA concentrations were used, the observed basic level of genomic DNA methylation increased to 11% depending on the position of CpG site. Qiagen and Chemicon kits recovered no more than 20% starting material at a high DNA input (500 ng/probe) and only 2.7–5.8% for low DNA input (10 ng/probe). EZ DNA Methylation-Gold Kit from Zymo Research provided the highest recovery regardless of the initial DNA input with average rates of no less than 86%. These results suggest that the EZ DNA Methylation-Gold Kit is the most appropriate tool for bisulfite modification of cirDNA when assaying DNA in low amounts.

Exposures in early life: associations with DNA promoter methylation in breast tumors.

There is evidence that epigenetic changes occur early in breast carcinogenesis. We hypothesized that early-life exposures associated with breast cancer would be associated with epigenetic alterations in breast tumors. In particular, we examined DNA methylation patterns in breast tumors in association with several early-life exposures in a population-based case-control study. Promoter methylation of E-cadherin, p16 and RAR-β2 genes was assessed in archived tumor blocks from 803 cases with real-time methylation-specific PCR. Unconditional logistic regression was used for case-case comparisons of those with and without promoter methylation. We found no differences in the prevalence of DNA methylation of the individual genes by age at menarche, age at first live birth and weight at age 20. In case-case comparisons of premenopausal breast cancer, lower birth weight was associated with increased likelihood of E-cadherin promoter methylation (OR = 2.79, 95% CI, 1.15-6.82, for ⩽2.5 v. 2.6-2.9 kg); higher adult height with RAR-β2 methylation (OR = 3.34, 95% CI, 1.19-9.39, for ⩾1.65 v. <1.60 m); and not having been breastfed with p16 methylation (OR = 2.75, 95% CI, 1.14-6.62). Among postmenopausal breast cancers, birth order was associated with increased likelihood of p16 promoter methylation. Being other than first in the birth order was inversely associated with likelihood of ⩾1 of the three genes being methylated for premenopausal breast cancers, but positively associated with methylation in postmenopausal women. These results suggest that there may be alterations in methylation associated with early-life exposures that persist into adulthood and affect breast cancer risk.

Label-free methylation specific sensor based on silicon microring resonators for detection and quantification of DNA methylation biomarkers in bladder cancer

Abstract Detection and quantification of DNA methylation is important to provide an opportunity to resolve clinical issues such as cancer early detection, progression, and drug treatments. In spite of myriad current technologies for DNA methylation detection that have been developed in last decade, they are still complicated and inadequate to be used as in vitro clinical diagnostic device. This work presents the first methylation specific sensor based on the silicon microring resonators which achieves fast, simple and specific label-free detection of DNA methylation after the bisulfite conversion. The methylated promoter regions of three genes ( DAPK , E - cadherin and RARβ ), which have been widely studied as biomarkers for human cancers including bladder cancer, are used as the target DNA sequences. We show that the methylated targets are strongly captured by methylated probe compared to unmethylated probe or vice versa. The discrimination between methylated and unmethylated DNA sequences is achieved within 5 min after hybridization between target and probe. Additionally, we have quantified DNA methylation density using various proportions (100, 75, 50, 25, and 0% of methylation sites) of methylation sequences of DAPK gene. Finally, we confirmed that the sensor can clearly detect the methylation of RARβ gene by using amplified target from genomic DNA of cancer cells. Therefore, our technique can be used to detect and quantify the methylation density in cancer biomarkers.

Adenovirus-mediated RAR-β over-expression enhances ATRA-induced neuronal differentiation of rat mesenchymal stem cells

IntroductionThe retinoic acid (RA) signaling pathway plays important roles in neural development. All-trans retinoic acid (ATRA) activates the RA signal by regulating RAR-β in mesenchymal stem cell (MSC)-derived neuron cells. Here, we try to investigate whether RAR-β over-expression can affect neuronal differentiation of MSCs.Material and methodsThe RAR-β gene was constructed into adenovirus Ad-RAR-β by using the AdEasy system. The MSCs were infected with Ad-RAR-β. Real time-polymerase chain reaction (RT-PCR), Western blot and immunofluorescence were performed to detect the expression and localization of RAR-β. The MSCs were treated with 1 µmol/l ATRA and modified neuronal induction medium (MNM). Soma size and axon length of induced neurons were measured. Neural specific markers were detected by RT-PCR, western blot and immunofluorescence to evaluate neuronal differentiation.ResultsThe 1300 bp fragment of RAR-β gene was confirmed to be correctly cloned in the adenovirus vector. Cloudiness amplification of Ad-RAR-β was observed in HEK293 cells during package. After 48 h of Ad-RAR-β infection, about 70% of MSCs were RFP-positive. RAR-β expression was increased by about 1988-fold and located in the nucleus. RAR-β over-expression did not affect neuronal differentiation efficiency; however, soma size of induced neuron cells enlarged from 716.25 ±95.96 µm2 to 1160.12 ±352.65 µm2 and axon length from 64.17 ±11.88 µm to 83.98 ±13.69 µm. Neural markers other than nestin – NSE, MAP-2, Tau, and Tuj1 – were increased by 4- to 11-fold in RAR-β over-expressed neuron cells with ATRA/MNM induction compared with the Ad-null control group.ConclusionsOur results have demonstrated that adenovirus-mediated RAR-β over-expression could facilitate neuron cell types of MSCs in vitro, indicating that the RAR-β-activated RA signal might be a vital factor in neuronal differentiation.

Abstract A38: Aberrant expression of cell growth-critical genes in 4-nitroquinoline 1-oxide-induced mouse tumors and in human esophageal cancer tissues

Abstract Background: An animal model of 4-nitroquinoline 1-oxide(4-NQO)-induced oral and esophageal cancer is useful in study of human diseases, but the underlying molecular events remain to be determined. Tobacco smoke, the major risk factor for human oral and esophageal squamous cell carcinoma, alters expression of certain cell growth-critical genes (e.g., p-ERK1/2, COX-2, and RAR-β2). This study aimed to detect expression of these genes in 4-NQO-induced mouse tumors and then in esophageal cancer cell lines and tissues for association with clinicopathological and survival data from patients. Methods: C57LB6/129Sv mice were given in the drinking water to produce oral and esophageal cancers. qRT-PCR, Western blot, and immunohistochemistry were used to detect gene expressions in mouse tissues or human esophageal cancer tissues. Methylation-specific PCR and DNA sequence were performed to assess promoter methylation of RAR-β2 promoter. the Kaplan-Meier analysis was performed to associate gene expression with survival of patients. Results: 4-NQO induced premalignant and malignant lesions in mouse oral cavity and esophagus in a dose-dependent manner, which pathologically and morphologically mimicked human oral and esophageal cancers. Molecularly, 4-NQO inhibited RAR-β2 but induced p-Erk1/2 and COX-2 expression and RAR-β2 gene promoter methylation in mouse tumors. In vitro treatment with 4-NQO altered expression of RAR-β2, p-Erk1/2, and COX-2 in esophageal cell lines. Ex vivo expression of p-Erk1/2 and COX-2 in 90 cases of esophageal cancer patients was upregulated and p-ERK1/2 expression was associated with advanced clinical tumor stage and consumption of hot beverage, while COX-2 expression was associated with tumor de-differentiation in esophageal cancers. Furthermore, expression of p-Erk1/2 was associated with worse overall survival of esophageal cancer patients (p = 0.014), while COX-2 expression didn't reach statistically significant (p = 0.19). Knockdown of COX-2 expression using transient transfection of a COX-2 antisense expression vector inhibited Ki67 expression, an indicator of cell proliferation, in esophageal cancer cells. Conclusion: 4-NQO-induced lesions in mouse oral cavity and esophagus not only pathologically and morphologically mimicked human oral and esophageal cancers, but also shared some molecular alterations (e.g., aberrant expression of RAR-β2, p-Erk1/2, and COX-2). This study further demonstrated that targeting of the altered RAR-β2-led gene pathway could effectively suppress development of these now deadly cancers. Citation Format: Zhengduo Yang, Baoxiang Guan, Taoyan Men, Junya Fujimoto, Xiaochun Xu. Aberrant expression of cell growth-critical genes in 4-nitroquinoline 1-oxide-induced mouse tumors and in human esophageal cancer tissues. [abstract]. In: Proceedings of the Eleventh Annual AACR International Conference on Frontiers in Cancer Prevention Research; 2012 Oct 16-19; Anaheim, CA. Philadelphia (PA): AACR; Cancer Prev Res 2012;5(11 Suppl):Abstract nr A38.

The prognostic value of detection methylation level panel of gene in DNA circulating after and before treatment in patients with breast cancer.

67 Background: Objective of this study was to determine the concordance of promoter methylation of 14-3-3σ and ESR1 in circulating DNA of breast cancer patients with response and their association with clinicopathological parameters and disease prognosis. Methods: Plasmawas sampled prospectively from 110 patients diagnosed of breast cancer. A PCR quantitative technique was used to analyze the utility of circulating DNA with CpG island hypermethylation of ESR1, 14-3-3σ, Rar-B and APC genes promoter regions as breast cancer biomarkers. Results: The cutoff points for the genes methylated promoters were established from the ROC curves, selecting values that gave the maximal likelihood ratio. Presence of methylated ESR1 in serum of breast cancer patients was associated with ER-negative phenotype (p=0.0179); and presence of methylated 14-3-3σ was associated with T3-4 stage (p&lt;0.05) and nodal positive status (p&lt;0.05). Mean serum values of methylated genes before treatment was for ESR1:0.009µg/ml, 14-3-3σ:0.047µg/ml, Rar B:0.0001µg/ml and APC:0.012µg/ml. Mean serum values of methylated genes after treatment was for ESR1:0.003 µg/ml, 14-3-3σ:0.038µg/ml, Rar-B:0 µg/ml and APC:0.001µg/ml. In the light of the discriminatory power of ESR1 and 14-3-3σ and the finding that serum levels of methylated gene promoters changed after breast cancer treatment, post-treatment modifications in these two promoters were analyzed. We observed lower methylated ERS1,14-3-3-σ and APC values after surgery, respect pretreatment levels, but without an overall statistically significant difference.With a median follow-up of 8 years, we found that patients with a significant decrease of sera methylated levels of these genes after surgery had better time to progression an overall survival respect patients without this observation. Conclusions: These findings cast some doubts on the utility for early cancer diagnosis of highly sensitive techniques to identify hypermethylation of specific gene promoters in DNA extracted from serum. Although numerous issues remain to be resolved, the quantitative measurement of circulating methylated DNA is a promising tool for cancer prognostic assessment.

Tumor suppressor gene methylation in tissue and urine specimens of bladder transitional cell carcinoma

Objective To investigate abnormal promoter methylation status of death-associated protein kinase(DAPK),retinoic acid receptorβ(RARβ),Hyperplastic polyps protein(HPP1) and integrin alpha-4 precursor (ITGA4) genes,and the diagnostic value for bladder transitional cell carcinoma (BTCC).Methods Methylation-specific polymerase chain reaction (MSP) was used to detect the methylation status of DAPK,RARβ,HPP1 and ITGA4 genes in tissue and urine specimens of 112 patients with BTCC.Results The methylation rate of DAPK,RARβ,HPP1 and ITGA4 in BTCC tissue was 29.4％,91.0％,75.0％ and 48.2％ respectively,and that in urine sediment cells was 26.7％,87.5％,69.6％ and 27.6％ respectively.Aberrant methylation rate of DAPK,HPP1 and RARβ genes in BTCC was significantly different from that in the glandular cystitis (P ＜ 0.05).There was no significant difference in the methylation rate of ITGA4 between BTCC and and cystitis glandularis (P ＞ 0.05).Conclusion Aberrant methylation status of HPP1,DAPK1,and RARβ is closely related with incidence of bladder cancer. Key words: Bladder carcinoma; Urine sediment cells; Tumor suppressor gene; Methylation