• The Korean Journal of Physiology and Pharmacology
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• v.5 no.6
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• pp.495-501
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• 2001

We have cloned the mouse neurotensin/neuromedin N (NT/N) gene from the murine mast cell line Cl.MC/C57.1 for the first time. The murine NT/N cDNA clone consisted of 765 nucleotides and coded for 169 peptide residues with an N-terminal signal peptide, and the C-terminal region contained of one copy of neurotensin (NT) and one copy of neuromedin N (NN). Total of four Lys-Arg dibasic motifs were present; one each at the middle of the open reading frame, at the N-terminal of NN, at the C-terminal of NT, and between NN and NT. Amino acid sequence analysis of the mouse NT/N revealed 90% homology to that of the rat NT/N gene. NT/N is expressed in murine mast cell lines (Cl.MC/C57.1 and P815), but not in murine bone marrow-derived mast cells (BMMCs), murine macrophage cell line (RAW 264.7), nor in murine T cell line (EL-4). NT/N mRNA in C1.MC/C57.1 is highly inducible by IgE cross-linking, phorbol myristate acetate, neurotensin, and substance P. Following the treatment of demethylating agent, 5-azacytidine (5-azaC), the NT/N gene was induced in BMMCs in response to IgE cross-linking. 5-azaC-treated BMMCs did not express the NT/N gene without additional stimuli. These findings suggested that the regulation of NT/N gene expression was dependent on the effects of not only gene methylation but also enhancer and/or repressor proteins acting on the NT/N promoter.

• Journal of Ginseng Research
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• v.43 no.4
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• pp.625-634
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• 2019

Background: Ginsenoside Rg3, a derivative of steroidal saponins abundant in ginseng, has a range of effects on cancer cells, including anti-cell proliferation and anti-inflammation activity. Here, we investigate two long noncoding RNAs (lncRNAs), STXBP5-AS1 and RFX3-AS1, which are hypomethylated and hypermethylated in the promoter region by Rg3 in MCF-7 cancer cells. Methods: The lncRNAs epigenetically regulated by Rg3 were mined using methylation array analysis. The effect of the lncRNAs on the apoptosis and proliferation of MCF-7 cells was monitored in the presence of Rg3 or Korean Red Ginseng (KRG) extract after deregulating the lncRNAs. The expression of the lncRNAs and their target genes was examined using qPCR and Western blot analysis. The association between the expression of the target genes and the survival rate of breast cancer patients was analyzed using the Kaplan-Meier Plotter platform. Results: STXBP5-AS1 and RFX3-AS1 exhibited anti- and pro-proliferation effects, respectively, in the cancer cells, and the effects of Rg3 and KRG extract on apoptosis and cell proliferation were weakened after deregulating the lncRNAs. Of the genes located close to STXBP5-AS1 and RFX3-AS1 on the chromosome, STXBP5, GRM1, RFX3, and SLC1A1 were regulated by the lncRNAs on the RNA and protein level. Breast cancer patients that exhibited a higher expression of the target genes of the lncRNAs had a higher metastasis-free survival rate. Conclusion: The current study is the first to identify lncRNAs that are regulated by the presence of Rg3 and KRG extract and that subsequently contribute to inhibiting the proliferation of cancer cells.

• Journal of Life Science
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• v.18 no.4
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• pp.580-584
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• 2008

$O^6-methylguanine-DNA$ methyltransferase (MGMT) is a DNA repair protein that protects cells against the carcinogenic effects of alkylating agents. The loss of MGMT expression was commonly known due to hypermethylation of CpG islands in its promoter region. We evaluated the expression of MGMT by immunohistochemistry in order to examine the relationship between loss of MGMT expression and clinicopathological characteristics in 74 Korean patients with non-small cell lung cancers. Loss of MGMT was detected in 25 (33.8%) of 74 cases. The loss of MGMT expression was frequently seen in the adenocarcinoma than in the squamous cell carcinoma (p=0.021). However, there was no significant differences between loss of MGMT expression and other clinicopathological characteristics, including age, gender, smoking status, tumor size, tumor T stage, and lymph node metastasis (p>0.05). In conclusion, loss of MGMT expression was related with the histologic type of lung cancer. Further methylation study of MGMT promoter is needed to evaluate the relationships with immunohistochemical expression of MGMT and to clarify the role of MGMT in lung cancer.

• Molecules and Cells
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• v.39 no.8
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• pp.631-638
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• 2016

Glutathione peroxidase 3 (GPx3), an antioxidant enzyme, acts as a modulator of redox signaling, has immunomodulatory function, and catalyzes the detoxification of reactive oxygen species (ROS). GPx3 has been identified as a tumor suppressor in many cancers. Although hyper-methylation of the GPx3 promoter has been shown to down-regulate its expression, other mechanisms by which GPx3 expression is regulated have not been reported. The aim of this study was to further elucidate the mechanisms of GPx3 regulation. GPx3 gene analysis predicted the presence of ten glucocorticoid response elements (GREs) on the GPx3 gene. This result prompted us to investigate whether GPx3 expression is regulated by the glucocorticoid receptor (GR), which is implicated in tumor response to chemotherapy. The corticosteroid dexamethasone (Dex) was used to examine the possible relationship between GR and GPx3 expression. Dex significantly induced GPx3 expression in H1299, H1650, and H1975 cell lines, which exhibit low levels of GPx3 expression under normal conditions. The results of EMSA and ChIP-PCR suggest that GR binds directly to GRE 6 and 7, both of which are located near the GPx3 promoter. Assessment of GPx3 transcription efficiency using a luciferase reporter system showed that blocking formation of the GR-GRE complexes reduced luciferase activity by 7-8-fold. Suppression of GR expression by siRNA transfection also induced down-regulation of GPx3. These data indicate that GPx3 expression can be regulated independently via epigenetic or GR-mediated mechanisms in lung cancer cells, and suggest that GPx3 could potentiate glucocorticoid (GC)-mediated anti-infla-mmatory signaling in lung cancer cells.

• Korean Journal of Clinical Oncology
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• v.9 no.2
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• pp.80-86
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• 2013

Purpose: Hypermethylation of human mut L homologue 1 (hMLH1) promoter region is known to cause sporadic microsatellite instability (MSI) colorectal cancers. 5,10-methylenetetrahydrofolate reductase (MTHFR) is the key enzyme in folate metabolism, acting as a methyl donor for DNA methylation. In this study, we investigate whether the polymorphism of MTHFR 677C>T plays a role in the alteration of the promoter-specific hypermethylation, predisposing to MSI colorectal cancers. Methods: Total of 487 sporadic colorectal cancer patients in CHA Bundang Medical Center were collected. MSI was identified when two or more are positive among five microsatellite markers (BAT25, BAT26, D17S250, D5S346, D2S123). The others were classified as microsatellite stable (MSS). Polymorphism of MTHFR 677C>T was genotyped by the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Results: MSI was observed in 65 of 487 patients (12.73%). MSI colorectal cancers showed similar clinicopathological features with previously reported; younger age onset, right-sided preponderance, mucinous and poorly differentiated histology, lower stage, fewer lymph node metastases than MSS tumors (each P<0.05). The frequency of MTHFR 677TT genotype was 17.7% in the MSI group higher than 14.6% in the MSS group (P=0.17). Although not statistically significant, compared to the MTHFR 677CC referent, MTHFR 677 CT+TT genotype was more likely to have MSI than MSS (odds ratio, 1.81; 95% confidence interval, 0.94 to 3.68; P=0.06). Conclusion: This study demonstrated higher frequency of MTHFR 677TT genotype in MSI colorectal cancers. Furthermore, individuals with MTHFR 677CT+TT variant type might potentially develop MSI rather than MSS colorectal cancers.

• Molecules and Cells
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• v.40 no.9
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• pp.667-676
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• 2017

Abnormal differentiation of muscle is closely associated with aging (sarcopenia) and diseases such as cancer and type II diabetes. Thus, understanding the mechanisms that regulate muscle differentiation will be useful in the treatment and prevention of these conditions. Protein lysine acetylation and methylation are major post-translational modification mechanisms that regulate key cellular processes. In this study, to elucidate the relationship between myogenic differentiation and protein lysine acetylation/methylation, we performed a PCR array of enzymes related to protein lysine acetylation/methylation during C2C12 myoblast differentiation. Our results indicated that the expression pattern of HDAC11 was substantially increased during myoblast differentiation. Furthermore, ectopic expression of HDAC11 completely inhibited myoblast differentiation, concomitant with reduced expression of key myogenic transcription factors. However, the catalytically inactive mutant of HDAC11 (H142/143A) did not impede myoblast differentiation. In addition, wild-type HDAC11, but not the inactive HDAC11 mutant, suppressed MyoD-induced promoter activities of MEF2C and MYOG (Myogenin), and reduced histone acetylation near the E-boxes, the MyoD binding site, of the MEF2C and MYOG promoters. Collectively, our results indicate that HDAC11 would suppress myoblast differentiation via regulation of MyoD-dependent transcription. These findings suggest that HDAC11 is a novel critical target for controlling myoblast differentiation.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.4
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• pp.2185-2193
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• 2016

Background: The pathogenesis of sporadic colorectal cancer (CRC) is influenced by the patient genetic background and environmental factors. Based on prior understanding, these are classified in two major pathways of genetic instability. Microsatellite instability (MSI) and CPG island methylator phenotype (CIMP) are categorized as features of the hypermethylated prototype, and chromosomal instability (CIN) is known to be indicative of the non-hypermethylated category. Secreted frizzled related protein 2 (SFRP2), APC1A in WNT signaling pathway and the DNA repair gene, O6-methylguanine-DNA methyltransferase (MGMT), are frequently hypermethylated in colorectal cancer. Detection of methylated DNA as a biomarker by easy and inexpensive methods might improve the quality of life of patients with CRC via early detection of cancer or a precancerous condition. Aim: To evaluate the rate of SFRP2 and MGMT hypermethylation in both polyp tissue and serum of patients in south Iran as compared with matched control normal population corresponding samples. Materials and Methods: Methylation-specific PCR was used to detect hypermethylation in DNA extracted from 48 polypoid tissue samples and 25 healthy individuals. Results: Of total polyp samples, 89.5% had at least one promoter gene hypermethylation. The most frequent methylated locus was SFRP2 followed by MGMT-B (81.2 and 66.6 percent respectively). Serologic detection of hypermethylation was 95% sensitive as compared with polyp tissue. No hypermethylation was detected in normal tissue and serum and its detection in patients with polyps, especially of serrated type, was specific. Conclusions: Serologic investigation for detection of MGMT-B, SFRP2 hypermethylation could facilitate prioritization of high risk patients for colonoscopic polyp detection and excision.

• Experimental and Molecular Medicine
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• v.50 no.12
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• pp.1.1-1.14
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• 2018

DNA methylation is a regulatory mechanism in epigenetics that is frequently altered during human carcinogenesis. To detect critical methylation events associated with gastric cancer (GC), we compared three DNA methylomes from gastric mucosa (GM), intestinal metaplasia (IM), and gastric tumor (GT) cells that were microscopically dissected from an intestinal-type early gastric cancer (EGC) using methylated DNA binding domain sequencing (MBD-seq) and reduced representation bisulfite sequencing (RRBS) analysis. In this study, we focused on differentially methylated promoters (DMPs) that could be directly associated with gene expression. We detected 2,761 and 677 DMPs between the GT and GM by MBD-seq and RRBS, respectively, and for a total of 3,035 DMPs. Then, 514 (17%) of all DMPs were detected in the IM genome, which is a precancer of GC, supporting that some DMPs might represent an early event in gastric carcinogenesis. A pathway analysis of all DMPs demonstrated that 59 G protein-coupled receptor (GPCR) genes linked to the hypermethylated DMPs were significantly enriched in a neuroactive ligand-receptor interaction pathway. Furthermore, among the 59 GPCRs, six GI hormone receptor genes (NPY1R, PPYR1, PTGDR, PTGER2, PTGER3, and SSTR2) that play an inhibitory role in the secretion of gastrin or gastric acid were selected and validated as potential biomarkers for the diagnosis or prognosis of GC patients in two cohorts. These data suggest that the loss of function of gastrointestinal (GI) hormone receptors by promoter methylation may lead to gastric carcinogenesis because gastrin and gastric acid have been known to play a role in cell differentiation and carcinogenesis in the GI tract.

• Proceedings of the KSAR Conference
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• 2004.06a
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• pp.228-228
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• 2004

Interferon-tau (IFN-τ) is the primary agent responsible for maternal recognition of pregnancy in cattle. Bovine embryos begine to express IFN-τ as the blastocyst forms. Pregnancy recognition in ruminants occurs when IFN-τ from the trophoblast prevents the increase of oxytocin receptors, disrupting luteolytic pulses of prostaglandin (PG) F2a by oxytocin. The expression of IFN-τ is strongly associated with the degree of methylation of the CpG islands in promoter region. (omitted)

• Molecules and Cells
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• v.41 no.5
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• pp.381-389
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• 2018

ARF is a tumor suppressor protein that has a pivotal role in the prevention of cancer development through regulating cell proliferation, senescence, and apoptosis. As a factor that induces senescence, the role of ARF as a tumor suppressor is closely linked to the p53-MDM2 axis, which is a key process that restrains tumor formation. Thus, many cancer cells either lack a functional ARF or p53, which enables them to evade cell oncogenic stress-mediated cycle arrest, senescence, or apoptosis. In particular, the ARF gene is a frequent target of genetic and epigenetic alterations including promoter hyper-methylation or gene deletion. However, as many cancer cells still express ARF, pathways that negatively modulate transcriptional or post-translational regulation of ARF could be potentially important means for cancer cells to induce cellular proliferation. These recent findings of regulators affecting ARF protein stability along with its low levels in numerous human cancers indicate the significance of an ARF post-translational mechanism in cancers. Novel findings of regulators stimulating or suppressing ARF function would provide new therapeutic targets to manage cancer- and senescence-related diseases. In this review, we present the current knowledge on the regulation and alterations of ARF expression in human cancers, and indicate the importance of regulators of ARF as a prognostic marker and in potential therapeutic strategies.