• BMB Reports
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• v.50 no.9
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• pp.472-477
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• 2017

The transcription repressor Bach2 has been proposed as a regulator of T cell quiescence, but the underlying mechanism is not fully understood. Given the importance of interleukin-2 in T cell activation, we investigated whether Bach2 is a component of the network of factors that regulates interleukin-2 expression. In primary and transformed $CD4^+$ T cells, Bach2 overexpression counteracted T cell receptor/CD28- or PMA/ionomycin-driven induction of interleukin-2 expression, and silencing of Bach2 had the opposite effect. Luciferase and chromatin immunoprecipitation assays revealed that Bach2 binds to multiple Maf-recognition element-like sites on the interleukin-2 proximal promoter in a manner competitive with AP-1, and thereby represses AP-1-driven induction of interleukin-2 transcription. Thus, this study demonstrates that Bach2 is a direct repressor of the interleukin-2 gene in $CD4^+$ T cells during the immediate early phase of AP-driven activation, thereby playing an important role in the maintenance of immune quiescence in the steady state.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.8
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• pp.4147-4151
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• 2012

The current study was conducted to explore the inhibitory effects of a small interfering RNA (siRNA) on 3-phosphoinositide-dependent protein kinase 1 (PDK1) expression in esophageal cancer 9706 (EC9706) cells and the influence on their biological behavior. After transfection of a synthesized PDK1 siRNA, PDK1 mRNA and protein expression and the phosphorylation level of the downstream Akt protein were assessed using RT-PCR and Western blot analysis. Proliferation, apoptosis, cell invasion and in vivo tumor formation capacity were also investigated using MTT, flow cytometry, Transwell invasion trials, and nude mouse tumor transplantion, respectively. PDK1 siRNA effectively suppressed PDK1 mRNA and protein expression, and down-regulated the phosphorylation level of the Akt protein in the EC9706 cells (P < 0.05). It also inhibited cell proliferation and invasion, and promoted apoptosis; such effects were particularly obvious at 48 h and 72 h after transfection (P < 0.05). Growth of transplanted tumors was inhibited in nude mice, with decreased PDK1 expression in tumor tissues. PDK1 may be closely correlated with proliferation, apoptosis and invasion of esophageal cancer cells and thus may serve as an effective target for gene therapy.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.7
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• pp.3507-3511
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• 2012

Objective: The aim of this study was to investigate possible mechanisms of LOX gene effects on invasion and metastasis of breast cancer cells by RNA interference. Methods: LOX-RNAi-LV was designed, synthesized, and then transfected into a breast cancer cell line (MDA-MB-231). Expression of LOX, MMP-2 and MMP-9 was determined by real-time PCR, and protein expression of LOX by Western blotting. Cell migration and invasiveness were assessed with Transwell chambers. A total of 111 cases of breast cancer tissues, cancer-adjacent normal breast tissues, and 20 cases of benign lesion tissues were assessed by immunohistochemistry. Results: Expression of LOX mRNA and protein was suppressed, and the expression of MMP-2 and MMP-9 was significantly lower in the RNAi group than the control group (P<0.05), after LOX-RNAi-LV was transfection into MDA-MB-231 cells. Migration and invasion abilities were obviously inhibited. The expression of LOX protein in breast cancer, cancer-adjacent normal breast tissues and benign breast tumor were 48.6% (54/111), 26.1% (29/111), 20.0% (4/20), respectively, associations being noted with clinical stage, lymph node metastasis, tumor size and ER, PR, HER2, but not age. LOX protein was positively correlated with MMP-2 and MMP-9. Conclusion: LOX displayed an important role in invasion and metastasis of breast cancer by regulating MMP-2 and MMP-9 expression which probably exerted synergistic effects on the extracellular matrix (ECM).

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.2
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• pp.1017-1021
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• 2013

The cellular apoptosis susceptibility (CSE1L) gene has been demonstrated to regulate multiple cellular mechanisms including the mitotic spindle check point as well as proliferation and apoptosis. However, the importance of CSE1L in human colon cancer is largely unknown. In the present study, we examined expression levels of CSE1L mRNA by semiquantitative RT-PCR. A lentivirus-mediated small interfering RNA (siRNA) was used to knock down CSE1L expression in the human colon cancer cell line RKO. Changes in CSE1L target gene expression were determined by RT-PCR. Cell proliferation was examined by a high content screening assay. In vitro tumorigenesis was measured by colony-formation assay. Cell cycle distribution and apoptosis were detected by flow cytometric analysis. We found CSE1L mRNA to be expressed in human colon cancer cells. Using a lentivirus based RNAi approach, CSE1L expression was significantly inhibited in RKO cells, causing cell cycle arrest in the G2/M and S phases and a delay in cell proliferation, as well as induction of apoptosis and an inhibition of colony growth capacity. Collectively, the results suggest that silencing of CSE1L may be a potential therapeutic approach for colon cancer.

• Molecules and Cells
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• v.26 no.3
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• pp.285-290
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• 2008

Estrogen-induced proliferation in estrogen receptor (ER)-positive breast cancer cells is primarily mediated through two distinct intracellular receptors, $ER{\alpha}$ and $ER{\beta}$. Although tumor necrosis factor alpha ($TNF{\alpha}$) and $E2/ER{\alpha}$ are known to exert opposing effects on cell proliferation in MCF-7 cells, the mechanism by which $TNF{\alpha}$ antagonizes $E2/ER{\alpha}$-mediated cell proliferation is not well understood. The present study suggests that reduced cell survival in response to $TNF{\alpha}$ treatment in MCF-7 cells may be associated with the down-regulation of $ER{\alpha}$ protein. The decrease in $ER{\alpha}$ protein level was accompanied by an inhibition of $ER{\alpha}$ gene transcription. Cell viability was decreased synergistically by the combined treatment with $ER{\alpha}$-siRNA and $TNF{\alpha}$. Furthermore, pretreatment of cells with the PI3-kinase (PI3K)/ Akt inhibitor, LY294002, markedly enhanced $TNF{\alpha}$-induced down-regulation of the $ER{\alpha}$ protein, suggesting that the PI3K/Akt pathway might be involved in control of the $ER{\alpha}$ level. Moreover, down-regulation of $ER{\alpha}$ by $TNF{\alpha}$ was not inhibited in cells that were pretreated with the proteasome inhibitors, MG132 and MG152, which suggests that proteasome-dependent proteolysis does not significantly influence $TNF{\alpha}$-induced down-regulation of $ER{\alpha}$ protein. In contrast, the effect of the PI3K/Akt inhibitor on $ER{\alpha}$ was blocked in cells that were treated with LY294002 in the presence of the proteasome inhibitors. Collectively, our findings show that the $TNF{\alpha}$ may partly regulate the growth of MCF-7 breast cancer cells through the down-regulation of $ER{\alpha}$ expression, which is primarily mediated by a PI3K/Akt signaling.

• Molecules and Cells
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• v.41 no.6
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• pp.575-581
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• 2018

Postmenopausal osteoporosis (PMOP) is a common systemic skeletal disease characterized by reduced bone mass and microarchitecture deterioration. Although differentially expressed SOX5 has been found in bone marrow from ovariectomized mice, its role in osteogenic differentiation in human mesenchymal stem cells (hMSCs) from bone marrow in PMOP remains unknown. In this study, we investigated the biological function of SOX5 and explore its molecular mechanism in hMSCs from patients with PMOP. Our findings showed that the mRNA and protein expression levels of SOX5 were upregulated in hMSCs isolated from bone marrow samples of PMOP patients. We also found that SOX5 overexpression decreased the alkaline phosphatase (ALP) activity and the gene expression of osteoblast markers including Collagen I, Runx2 and Osterix, which were increased by SOX5 knockdown using RNA interference. Furthermore, $TNF-{\alpha}$ notably upregulated the SOX5 mRNA expression level, and SOX5 knockdown reversed the effect of $TNF-{\alpha}$ on osteogenic differentiation of hMSCs. In addition, SOX5 overexpression increased Kruppel-like factor 4 (KLF4) gene expression, which was decreased by SOX5 silencing. KLF4 knockdown abrogated the suppressive effect of SOX5 overexpression on osteogenic differentiation of hMSCs. Taken together, our results indicated that $TNF-{\alpha}$-induced SOX5 upregulation inhibited osteogenic differentiation of hMSCs through KLF4 signal pathway, suggesting that SOX5 might be a novel therapeutic target for PMOP treatment.

• Korean Journal of Plant Tissue Culture
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• v.24 no.3
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• pp.161-165
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• 1997

The R-mb locus of maize is one of several genes that encode tissue-specific transcriptional regulator for the anthocyanin biosynthesis in plant parts and the aleurone layer in seeds. We found that the seed pigment frequencies gradually decreased at selfed progenies of the R-mb genetic stocks. In order to analyze the genomic structure of R-mb locus components, genomic Southern blot was performed by using R specific probe, pR-nj:1. Two bands were detected at the size of about 3.9 and 7.75kb. Five R-mb positive clones (mb-II, III, V,Ⅵ, and Ⅶ) were obtained by screening of maize genomic λFIXII library using R specific probe pR-nj:1. We constructed the restriction map of clone mb-II (7.75Kb positive) and mb-Ⅵ (3.9Kb positive), and have compared these with other R locus genes. From genetic and molecular analysis, it is suggested that R-mb complex consists two copy of R elements, and each element shows the paramutagenic and gene silencing effects by the fashion of cis-inactivation.

• Molecules and Cells
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• v.43 no.1
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• pp.23-33
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• 2020

NF-κB signaling through both canonical and non-canonical pathways plays a central role in immune responses and inflammation. NF-κB-inducing kinase (NIK) stabilization is a key step in activation of the non-canonical pathway and its dysregulation implicated in various hematologic malignancies. The tumor suppressor, p53, is an established cellular gatekeeper of proliferation. Abnormalities of the TP53 gene have been detected in more than half of all human cancers. While the non-canonical NF-κB and p53 pathways have been explored for several decades, no studies to date have documented potential cross-talk between these two cancer-related mechanisms. Here, we demonstrate that p53 negatively regulates NIK in an miRNA-dependent manner. Overexpression of p53 decreased the levels of NIK, leading to inhibition of the non-canonical NF-κB pathway. Conversely, its knockdown led to increased levels of NIK, IKKα phosphorylation, and p100 processing. Additionally, miR-34b induced by nutlin-3 directly targeted the coding sequences (CDS) of NIK. Treatment with anti-miR-34b-5p augmented NIK levels and subsequent non-canonical NF-κB signaling. Our collective findings support a novel cross-talk mechanism between non-canonical NF-κB and p53.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.6
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• pp.2757-2760
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• 2016

Gastric cancer (GC) is the fourth most prevalant cancer and the second leading cause of cancer-related mortality worldwide. As in other cancers gastric carcinogenesis is multifactorial involving environmental, genetic and epigenetic components. Epigenetic silencing due to hypermethylation of tumour suppressor genes is one of the key events in gastric carcinogenesis. This study was aimed to analyse the hypermethylation status of the E-Cadherin (CDH1) gene promoter in GCs in the ethnic Kashmiri population. In this study a total of 80 GC patients were recruited. Hypermethylation in tumour tissue was detected by methylation specific PCR (MS-PCR). Hypermethylation of CDH1 promoter was observed in 52 (65%) of gastric carcinoma cases which was significantly much higher than adjacent normal tissue [$p{\leq}0.0001$]. Further the frequency of CDH1 promoter methylation was significantly different with intestinal and diffuse types of gastric cancer [55.7% vs 82.1%; p<0.05]. Moreover females and cases with lymph node invasion had higher frequencies of CDH1 hypermethylation [$P{\leq}0.05$]. Thus the current data indicate a vital role of epigenetic alteration of CDH1 in the causation and development of gastric cancer, particularly of diffuse type, in our population.

• Journal of Ginseng Research
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• v.45 no.6
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• pp.734-743
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• 2021

Background: The underlying mechanisms of the potential tumor-suppressive effects of ginsenoside Rh2 are complex. N6-methyladenosine (m6A) RNA methylation is usually dysregulated in cancer. This study explored the regulatory effect of ginsenoside Rh2 on m6A RNA methylation in cancer. Methods: m6A RNA quantification and gene-specific m6A RIP-qPCR assays were applied to assess total and gene-specific m6A RNA levels. Co-immunoprecipitation, fractionation western blotting, and immunofluorescence staining were performed to detect protein interactions and distribution. QRT-PCR, dual-luciferase, and ChIP-qPCR assays were conducted to check the transcriptional regulation. Results: Ginsenoside Rh2 reduces m6A RNA methylation and KIF26B expression in a dose-dependent manner in some cancers. KIF26B interacts with ZC3H13 and CBLL1 in the cytoplasm of cancer cells and enhances their nuclear distribution. KIF26B inhibition reduces m6A RNA methylation level in cancer cells. SRF bound to the KIF26B promoter and activated its transcription. SRF mRNA m6A abundance significantly decreased upon KIF26B silencing. SRF knockdown suppressed cancer cell proliferation and growth both in vitro and in vivo, the effect of which was partly rescued by KIF26B overexpression. Conclusion: ginsenoside Rh2 reduces m6A RNA methylation via downregulating KIF26B expression in some cancer cells. KIF26B elevates m6A RNA methylation via enhancing ZC3H13/CBLL1 nuclear localization. KIF26B-SRF forms a positive feedback loop facilitating tumor growth.