scholarly journals Structural and Biophysical Analyses of Human N-Myc Downstream-Regulated Gene 3 (NDRG3) Protein

Biomolecules ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 90
Author(s):  
Kyung Rok Kim ◽  
Kyung A. Kim ◽  
Joon Sung Park ◽  
Jun Young Jang ◽  
Yuri Choi ◽  
...  

The N-Myc downstream-regulated gene (NDRG) family belongs to the α/β-hydrolase fold and is known to exert various physiologic functions in cell proliferation, differentiation, and hypoxia-induced cancer metabolism. In particular, NDRG3 is closely related to proliferation and migration of prostate cancer cells, and recent studies reported its implication in lactate-triggered hypoxia responses or tumorigenesis. However, the underlying mechanism for the functions of NDRG3 remains unclear. Here, we report the crystal structure of human NDRG3 at 2.2 Å resolution, with six molecules in an asymmetric unit. While NDRG3 adopts the α/β-hydrolase fold, complete substitution of the canonical catalytic triad residues to non-reactive residues and steric hindrance around the pseudo-active site seem to disable the α/β-hydrolase activity. While NDRG3 shares a high similarity to NDRG2 in terms of amino acid sequence and structure, NDRG3 exhibited remarkable structural differences in a flexible loop corresponding to helix α6 of NDRG2 that is responsible for tumor suppression. Thus, this flexible loop region seems to play a distinct role in oncogenic progression induced by NDRG3. Collectively, our studies could provide structural and biophysical insights into the molecular characteristics of NDRG3.

2021 ◽  
Author(s):  
Linfei Yang ◽  
Qian Li ◽  
Hai Zhong ◽  
Liang Ye ◽  
Surong Fang ◽  
...  

Abstract Background The disordered expression of maternally expressed gene 3 (MEG3) has been observed in non-small-cell lung cancer (NSCLC). However, the molecular mechanism accounting for this abnormal expression is not fully understood. Methods MEG3 expression was detected by qRT-PCR in 51 cases of NSCLC and adjacent normal tissues. Then, the relationship between MEG3 and miR-208a-3p was assessed in vitro by cell viability assay, cell migration assay, protein extraction and western blot analysis. Resoults We observed that MEG3 expression was decreased in NSCLC tissues. And MEG3 expression was negatively related to lymph node metastasis and differentiation. Moreover, MEG3 expression is regulated by miR-208a-3p expression by overexpression and knockout experiments. Furthermore, we focused on the underlying mechanism of MEG3 downregulation. We found that the overexpression of miR-208a-3p reduced the level of MEG3 expression based on computational predictions and in vitro assays. Using CCK-8 and transwell migration assays, we found that the overexpression of miR-208a-3p can increased proliferation and apoptosis in NSCLC cells. Moreover, the depletion of MEG3 rescued the proliferation and migration induced by miR-208a-3p knockdown. Conclusion Taken together, the results of this study reveal that miR-208a-3p promotes NSCLC tumorigenesis by negatively regulating MEG3 expression and functions as an oncogenic miRNA in NSCLC.


Marine Drugs ◽  
2019 ◽  
Vol 17 (2) ◽  
pp. 130
Author(s):  
Ping Liu ◽  
Jeong-Wook Choi ◽  
Min-Kyeong Lee ◽  
Youn-Hee Choi ◽  
Taek-Jeong Nam

Wound healing is a dynamic and complex process. The proliferation and migration of dermal fibroblasts are crucial for wound healing. Recent studies have indicated that the extracts from Spirulina platensis have a positive potential for wound healing. However, its underlying mechanism is not fully understood. Our previous study showed that spirulina crude protein (SPCP) promoted the viability of human dermal fibroblast cell line (CCD-986sk cells). In this study, we further investigated the wound healing effect and corresponding mechanisms of SPCP on CCD-986sk cells. Bromodeoxyuridine (BrdU) assay showed that SPCP promoted the proliferation of CCD-986sk cells. The wound healing assay showed that SPCP promoted the migration of CCD-986sk cells. Furthermore, cell cycle analysis demonstrated that SPCP promoted CCD-986sk cells to enter S and G2/M phases from G0/G1 phase. Western blot results showed that SPCP significantly upregulated the expression of cyclin D1, cyclin E, cyclin-dependent kinase 2 (Cdk2), cyclin-dependent kinase 4 (Cdk4), and cyclin-dependent kinase 6 (Cdk6), as well as inhibited the expression of CDK inhibitors p21 and p27 in CCD-986sk cells. In the meanwhile, SPCP promoted the phosphorylation and activation of phosphoinositide 3-kinase (PI3K) and protein kinase B (Akt). However, the phosphorylation of Akt was significantly blocked by PI3K inhibitor (LY294002), which in turn reduced the SPCP-induced proliferation and migration of CCD-986sk cells. Therefore, the results presenting in this study suggested that SPCP can promote the proliferation and migration of CCD-986sk cells; the PI3K/Akt signaling pathway play a positive and important role in these processes.


2019 ◽  
Vol 316 (3) ◽  
pp. L547-L557 ◽  
Author(s):  
Ruifeng Zhang ◽  
Hua Su ◽  
Xiuqing Ma ◽  
Xiaoling Xu ◽  
Li Liang ◽  
...  

Angiotensin-converting enzyme 2 (ACE2) protects against hypoxic pulmonary hypertension (HPH) by inhibiting the proliferation and migration of pulmonary artery smooth muscle cells (PASMCs). Under hypoxia, the hypoxia-inducible factor 1α (HIF-1α) inhibits ACE2 indirectly; however, the underlying mechanism is unclear. In the present study, we found that exposure to chronic hypoxia stimulated microRNA (miRNA) let-7b expression in rat lung via a HIF-1α-dependent pathway. Let-7b downregulated ACE2 expression by directly targeting the coding sequence of ACE2. Our in vitro and in vivo results revealed that let-7b contributed to the pathogenesis of HPH by inducing PASMCs proliferation and migration. Let-7b knockout mitigated right ventricle hypertrophy and pulmonary vessel remodeling in HPH by restoring ACE2 expression. Overall, we demonstrated that HIF-1α inhibited ACE2 expression via the HIF-1α-let-7b-ACE2 axis, which contributed to the pathogenesis of HPH by stimulating PASMCs proliferation and migration. Since let-7b knockout alleviated the development of HPH, let-7b may serve as a potential clinical target for the treatment of HPH.


2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Bin Liu ◽  
Xinli Zhan ◽  
Chong Liu

Introduction. Long noncoding RNAs (lncRNAs) have been implicated in a variety of biological functions, including tumor proliferation, apoptosis, progression, and metastasis. lncRNA metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) is overexpressed in various cancers, as well as osteosarcoma (OS); however, its underlying mechanism in OS is poorly understood. This investigation aims to elucidate the mechanisms of MALAT1 in OS proliferation and migration and to provide theoretical grounding for further targeted therapy in OS. Methods. In the present study, we applied qRT-PCR to assess the MALAT1 expression in OS tissues and cell lines. The effects of MALAT1 and miR-124-3p on OS cell proliferation and migration were studied by CCK-8 and scratch assays. Cell cycle and apoptosis were tested using a flow cytometer. The competing relationship between MALAT1 and miR-124-3p was confirmed by dual-luciferase reporter assay. Results. MALAT1 was overexpressed in OS cell lines and tissue specimens, and knockdown of MALAT1 significantly inhibited cell proliferation and migration and increased cell apoptosis and the percentage of G0/G1 phase. Furthermore, MALAT1 could directly bind to miR-124-3p and inhibit miR-124-3p expression. Moreover, MALAT1 overexpression significantly relieved the inhibition on OS cell proliferation mediated by miR-124-3p overexpression, which involved the derepression of sphingosine kinase 1 (SphK1). Conclusions. We propose that lncRNA MALAT1 interacts with miR-124-3p to modulate OS progression by targeting SphK1. Hence, we identified a novel MALAT1/miR-124-3p/SphK1 signaling pathway in the regulation of OS biological behaviors.


2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Guijun He ◽  
Wenfeng Yao ◽  
Liang Li ◽  
Yang Wu ◽  
Guojian Feng ◽  
...  

Abstract Background LOXL1-AS1 is a long non-coding RNA (lncRNA) that plays crucial roles in various cancers. However, the functional role of LOXL1-AS1 in laryngocarcinoma remains unclear. Thus we planned to probe into the function and underlying mechanism of LOXL1-AS1 in laryngocarcinoma. Methods Gene expression was evaluated in laryngocarcinoma cells using RT-qPCR. The ability of cell proliferation and migration was assessed by CCK8, colony formation, wound healing and transwell assays. The interaction among LOXL1-AS1, miR-589-5p and TRAF6 was detected by Ago2-RIP, RNA pull down and luciferase reporter assays. Results LOXL1-AS1 was overexpressed in laryngocarcinoma cells. Silencing of LOXL1-AS1 suppressed cell proliferation, migration and EMT in laryngocarcinoma. Moreover, miR-589-5p, the downstream of LOXL1-AS1, directly targeted TRAF6 in laryngocarcinoma. Importantly, LOXL1-AS1 augmented TRAF6 expression in laryngocarcinoma cells by sequestering miR-589-5p. Besides, miR-589-5p worked as a tumor-inhibitor while TRAF6 functioned as a tumor-facilitator in laryngocarcinoma. Of note, rescue experiments both in vitro and in vivo validated that LOXL1-AS1 aggravated the malignancy in laryngocarcinoma by targeting miR-589-5p/TRAF6 pathway. Conclusions LOXL1-AS1 promotes the proliferation and migration of laryngocarcinoma cells through absorbing miR-589-5p to upregulate TRAF6 expression.


2021 ◽  
Vol 12 (5) ◽  
Author(s):  
Ting Huang ◽  
Yong-Jie Wang ◽  
Mi-Tao Huang ◽  
Yu Guo ◽  
Li-Chang Yang ◽  
...  

AbstractRecently studies found that APEX1 was abnormally expressed in melanoma, indicating that it might be involved in the development of melanoma. However, the underlying mechanism and the interaction between APEX1 and LINC00470 in melanoma are not clear. Therefore, we aimed to investigate the role of LINC00470 in the development of melanoma in this work. We discovered that LINC00470 was overexpressed in melanoma tissues and cells compared with the adjacent normal tissues and cells by qPCR. The overexpression of LINC00470 promoted the proliferation and migration of melanoma cells. The functional investigation demonstrated that LINC00470 activated the transcription factor, ZNF131, to regulate the APEX1 expression, which finally promoted cell proliferation and migration. In contrast, knockdown of LINC00470 could significantly inhibit the melanoma cell proliferation and migration, and suppress the growth of tumor in vivo. Overexpression of APEX1 could reverse the impact of the silence of LINC00470 in melanoma cells. In summary, our studies revealed that LINC00470 promoted melanoma proliferation and migration by enhancing the expression of APEX1, which indicated that LINC00470 might be a therapeutic target for the treatment of melanoma.


Antioxidants ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 1357
Author(s):  
Hui-Hsuan Lin ◽  
Ming-Chang Hsieh ◽  
Chi-Ping Wang ◽  
Pei-Rong Yu ◽  
Ming-Shih Lee ◽  
...  

Gossypetin (GTIN), known as 3,5,7,8,3′,4′-hexahydroxyflavone, has been demonstrated to exert anti-atherosclerotic potential against apoptotic injury in oxidized low-density lipoprotein-incubated endothelial cells, and atherosclerotic lesions of cholesterol-fed rabbits. However, the effect and underlying mechanism of GTIN on abnormal vascular smooth muscle cells (VSMCs) proliferation and migration, a major event in the pathogenesis of atherosclerosis, is still unknown. In this study, non-cytotoxic doses of GTIN abolished the VSMCs A7r5 proliferation and cell-cycle S phase distribution. The GTIN-arrested G0/G1 phase might be performed by increasing the expressions of phosphorylated p53 and its downstream molecules that inhibit the activation of cyclin E/cyclin-dependent kinase (cdk)-2, blocking retinoblastoma protein (Rb) phosphorylation and the subsequent dissociation of Rb/transcription factor E2F1 complex. In addition, the results indicated that GTIN inhibited VSMCs wound-healing and migratory abilities through reducing matrix metalloproteinase (MMP)-9 activity and expression, as well as down-regulating protein kinase B (PKB)/nuclear factor-kappaB (NF-κB) signaling. GTIN also revealed potential in diminishing reactive oxygen species (ROS) generation. These findings suggested the inhibitory effects of GTIN on VSMCs dysfunction could likely lead to the containment of atherosclerosis and other cardiovascular illness.


2021 ◽  
Author(s):  
Shuchi Xia ◽  
Yiqun Ma

Abstract Background: Osteosarcomas (OS) are the most frequent primary malignant bone tumor. Emerging evidence revealed that karyopherin alpha 2 (KPNA2) was strongly associated with the tumorigenesis and development of numerous human cancers. The aim of the present study was to investigate the expression pattern, biological functions and underlying mechanism of KPNA2 in OS. Methods: Bioinformatics TFBIND online was applied to forecast the transcription factor (TF) binding sites in the promoter region of KPNA2. The expression profile of KPNA2 in OS tissues were firstly assessed using TARGET dataset. The expression of KPNA2 in clinical OS samples and normal human adjacent samples were analyzed by RT-qPCR and western blot. CCK8, colony formation, wound-healing, and Transwell assays were used to assess cell viability, proliferation and migration in vitro, and in vivo experiments were performed to explore the effects of KPNA2 and interferon regulatory factor-2 (IRF2) on tumor growth. In addition, the correlation between IRF2 and KPNA2, and their roles on the NF-κB/p65 was investigated using chromatin immunoprecipitation (ChIP), RT-qPCR, western blot and dual-luciferase assays. Results: KPNA2 was obviously upregulated while IRF2 was significantly decreased in OS tissues and cell lines, as well as they were negatively correlated with each other. KPNA2 knockdown remarkably suppressed OS cell growth, migration, invasion in vitro and tumor growth in vivo, while IRF2 knockdown exerts an opposing effect. IRF2 binds to KPNA2 promoter to modulate the tumorigenic malignant phenotypes of OS via regulating NF-κB/p65 signaling. Conclusion: The present study demonstrated that KPNA2 performed the oncogenic function, possibly regulating tumorigenesis through NF-κB/p65 signaling pathway. Importantly, IRF2 was confirmed to serve a potential upstream TF of KPNA2 involving in the regulation of NF-κB/p65 pathway in OS.


2020 ◽  
Author(s):  
Jiawei Gu ◽  
Runqi Hong ◽  
Gengming Niu ◽  
Zhiqing Hu ◽  
Tao Song ◽  
...  

Abstract Background Discs large MAGUK scaffold protein 2 (DLG2), a member of the MAGUK family, has been associated with certain tumor suppressing processes. In this study, we aim to identify the prognosis value and specific function of DLG2 in hepatocellular carcinomas (HCCs). Methods Expression of DLG2 in HCCs and adjacent normal tissues (NTs) was analyzed with transcriptomic datasets from the Integrative Molecular Database of Hepatocellular Carcinoma (HCCDB) and immunohistochemical (IHC) staining of a tissue microarray (TMA). Prognostic roles of DLG2 in HCCs were investigated in the TMA cohort and validated in two cohorts from HCCDB. The in vitro activities of DLG2 were investigated in cultured HCC cells with lentiviruses. The underlying mechanism was explored using Gene Set Enrichment Analysis (GSEA) and gene-gene correlation analyses with The Cancer Genome Atlas Liver Hepatocellular Carcinoma (TCGA-LIHC) dataset. Results The expression of DLG2 was significantly decreased in HCCs compared to that in NTs. Down-regulation of DLG2 in HCCs was associated with unfavorable prognosis. Overexpression of DLG2 inhibited, while knockdown of DLG2 prompted proliferation and migration of cultured HCCs. Mechanistically, DLG2 may inhibited cell growth of HCCs by interacting with key molecules that regulate cell cycles. Conclusion DLG2 inhibited HCC progression and may be a novel prognosis biomarker and therapeutic target for HCC.


2009 ◽  
Vol 297 (4) ◽  
pp. L631-L640 ◽  
Author(s):  
Ruifeng Zhang ◽  
Yingli Wu ◽  
Meng Zhao ◽  
Chuanxu Liu ◽  
Lin Zhou ◽  
...  

Angiotensin-converting enzyme (ACE) enhances the proliferation and migration of pulmonary artery smooth muscle cells (PASMCs), which contribute to the pathogenesis of hypoxic pulmonary hypertension (HPH). Previous reports have demonstrated that hypoxia upregulates ACE expression, but the underlying mechanism is unknown. Here, we found that ACE is persistently upregulated in PASMCs on the transcriptional level during hypoxia. Hypoxia-inducible factor 1α (HIF-1α), a key transcription factor activated during hypoxia, was able to upregulate ACE protein expression under normoxia, whereas knockdown of HIF-1α expression in PASMCs inhibited hypoxia-induced ACE upregulation. Furthermore, HIF-1α can bind and transactivate the ACE promoter directly. Therefore, we report that ACE is a novel target of HIF-1α. Recently, a homolog of ACE, ACE2, was reported to counterbalance the function of ACE. In contrast to ACE, we found that ACE2 mRNA and protein levels increased during the early stages of hypoxia and decreased to near-baseline levels at the later stages after HIF-1α accumulation. Thus HIF-1α inhibited ACE2 expression, and the accumulated ANG II catalyzed by ACE is a key mediator in the downregulation of ACE2 by HIF-1α. Moreover, a reduction of ACE2 expression in PASMCs by RNA interference was accompanied by significantly enhanced proliferation and migration during hypoxia. We conclude that ACE is directly regulated by HIF-1α, whereas ACE2 is regulated in a bidirectional way during hypoxia and may play a protective role during the development of HPH. In sum, these findings contribute to the understanding of the pathogenesis of HPH.


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