CD11b + CD43 hi Ly6C lo splenocyte-derived macrophages exacerbate liver fibrosis via spleen-liver axis.

BACKGROUND AND AIMS: Monocyte-derived macrophages (MoMFs), a dominant population of hepatic macrophages under inflammation, play a crucial role in liver fibrosis progression. The spleen serves as an extra monocyte reservoir in inflammatory conditions; however, the precise mechanisms of involvement of the spleen in the pathogenesis of liver fibrosis remain unclear. APPROACH AND RESULTS: By splenectomy and splenocyte transfusion, it was observed that splenic CD11b + cells accumulated intrahepatically as Ly6C lo MoMFs to exacerbate CCl 4 -induced liver fibrosis. The splenocyte migration into the fibrotic liver was further directly visualized by spleen-specific photoconversion with KikGR mice and confirmed by CD45.1 + /CD45.2 + spleen transplantation. Spleen-derived CD11b + cells purified from fibrotic livers were then annotated by single-cell RNA sequencing, and a subtype of CD11b + CD43 hi Ly6C lo splenic monocytes (sM-1s) was identified, which was markedly expanded in both spleens and livers of mice with liver fibrosis. sM-1s exhibited mature feature with high expressions of F4/80, produced much ROS, and manifested preferential migration into livers. Once recruited, sM-1s underwent sequential transformation to sM-2s (highly expressed Mif , Msr1 , Clec4d , and Cstb ) and then to spleen-derived macrophages (sMφs) with macrophage features of higher expressions of CX 3 CR1, F4/80, MHC class II, and CD64 in the fibrotic hepatic milieu. Furthermore, sM-2s and sMφs were demonstrated capable of activating hepatic stellate cells and thus exacerbating liver fibrosis. CONCLUSIONS: CD11b + CD43 hi Ly6C lo splenic monocytes migrate into the liver and shift to macrophages, which account for the exacerbation of liver fibrosis. These findings reveal precise mechanisms of spleen-liver axis in hepatic pathogenesis and shed light on the potential of sM-1 as candidate target for controlling liver diseases.

The hotspots and trends of nursing master's education in China: a bibliometric analysis from 2000 to 2022.

BACKGROUND: Graduate nursing education is the main way to train high-quality nursing personnel. Globally, the nursing education system has been gradually improved, forming a multi-level, multi-channel, and multi-specification education system including secondary, specialized, undergraduate, and postgraduate. OBJECTIVE: To analyze the research hotspots and trends of nursing postgraduate education in China by using bibliometric methods, and to provide reference for scholars at home and abroad to understand the current status of this field. METHODS: Literature related to graduate nursing education was searched in the Chinese full-text journal database (CNKI) from January 2000 to May 2022 and analyzed using CiteSpace software. RESULTS: A total of 998 kinds of literature were included, with a growing trend in the number of articles issued. The research hotspots and trends of nursing graduate education in China are clinical practice, cultivation mode, and core competence. CONCLUSION: Chinese nursing graduate education is improving. Foreign experience should be drawn upon, combined with the hotspots and trends summarized in this study, to promote the development of nursing graduate education in China.

PRMT5 regulates RNA m6A demethylation for doxorubicin sensitivity in breast cancer.

Cancer cells respond to various stressful conditions through the dynamic regulation of RNA m6A modification. Doxorubicin is a widely used chemotherapeutic drug that induces DNA damage. It is interesting to know whether cancer cells regulate the DNA damage response and doxorubicin sensitivity through RNA m6A modification. Here, we found that doxorubicin treatment significantly induced RNA m6A methylation in breast cancer cells in both a dose- and a time-dependent manner. However, protein arginine methyltransferase 5 (PRMT5) inhibited RNA m6A modification under doxorubicin treatment by enhancing the nuclear translocation of the RNA demethylase AlkB homolog 5 (ALKBH5), which was previously believed to be exclusively localized in the nucleus. Then, ALKBH5 removed the m6A methylation of BRCA1 for mRNA stabilization and further enhanced DNA repair competency to decrease doxorubicin efficacy in breast cancer cells. Importantly, we identified the approved drug tadalafil as a novel PRMT5 inhibitor that could decrease RNA m6A methylation and increase doxorubicin sensitivity in breast cancer. The strategy of targeting PRMT5 with tadalafil is a promising approach to promote breast cancer sensitivity to doxorubicin through RNA methylation regulation.

Prevalence and factors influencing depression among empty nesters in China: A meta-analysis.

BACKGROUND: Empty nesters are older people who live alone or an older couple without children to care for them. In China, empty nesters make up a significant community and are more likely to experience emotional issues, particularly depression. This study investigated the prevalence of depression and the factors influencing depression among Chinese home-bound empty nesters using meta-analysis. METHODS: Based on previous studies, we used search terms relating to empty nesters and depression in English and Chinese. Databases, including China Journal Full Text Database (CNKI), Wanfang, Wipu, China Biomedical Literature Database (CBM), PubMed, Web of Science, Embase, The Cochrane Library, and UptoDate, were searched in April 2022, for relevant articles. Details including names of authors, year of publication, region of investigation, study type, sample size, depression detection scale, depression detection rate, and influencing factors were captured. The heterogeneity of the studies was assessed based on the I2 index, and data analysis was performed using Stata 16.0 software. RESULTS: A total of ten research articles involving 5337 Chinese empty nesters were evaluated in the present meta-analysis. The overall prevalence of depression among empty nesters in China was 43%. The prevalence of depression among urban empty nesters was 38% (95% CI: 0.24,0.52), and 36% (95% CI: 0.18,0.55) among rural empty nesters. Many factors, including female, income, marital status, chronic illness, relationship with children, and social support were linked to depression among urban empty nesters. CONCLUSION: The prevalence of depression among empty nesters was 43%. Therefore, based on the factors influencing depression, government departments can intervene early to improve the mental health of empty nesters. LIMITATIONS: The meta-analysis only included cross-sectional studies. Therefore, there is a need for more future original studies investigating depression among empty nesters in China.

Analysis of hot spots and frontiers of nursing scenario simulation teaching research at home and abroad.

OBJECTIVE: To analyze the research hotspots and trends of nursing scenario simulation teaching at home and abroad, and to provide reference for future nursing talent education. METHODS: CNKI and Web of Science databases were searched. From the establishment of the database to April 2022, relevant literature on nursing scenario simulation teaching research at home and abroad was retrieved, and Cite Space software was used for visual analysis. RESULTS: The research focus on China was the application and application effect of nursing scenario simulation teaching. The research hotspots abroad are the quality evaluation, reliability and influence of nursing scenario simulation teaching. CONCLUSION: The research and development of nursing scenario simulation teaching gradually tend to be systematic.

A New Role for the Spleen: Aggravation of the Systemic Inflammatory Response in Rats with Severe Acute Pancreatitis.

Little is known about the role of the spleen in mediating systemic inflammatory responses in severe acute pancreatitis (SAP). We investigated the role played by the spleen in rats after SAP induction. Splenectomy was performed at designated time points after SAP induction. Pancreatic tissue and serum samples were collected and subjected to histologic, immunohistochemical, and immunologic analyses. After SAP induction, the splenic immune response was enhanced during SAP progression, as shown by the increased diameter of the splenic periarterial lymphatic sheath and the thickness of the splenic marginal zone. Rats with splenectomy developed acute pancreatitis more slowly than rats without splenectomy. In addition, pancreatic tissues of rats with splenectomy contained lower levels of serum amylase, tumor necrosis factor-α, and IL-6 and exhibited less acinar cell death, leukocyte infiltration, and interstitial edema than those of rats without splenectomy. Compared with splenectomy alone, cotreatment with splenectomy and the administration of splenic cells originating from a rat with SAP 12 hours after induction increased systemic inflammation in SAP rats. Splenic factors exacerbated SAP-associated liver and lung injury and accentuated intestinal mucosal barrier dysfunction. Splenectomy altered the serum cytokine profile in rats with SAP. In a rat model of SAP, the spleen exacerbated the systematic inflammatory responses and injury to multiple organs, indicating a new role for the spleen in SAP.

The tumor suppressor NDRG2 cooperates with an mTORC1 inhibitor to suppress the Warburg effect in renal cell carcinoma.

Renal cell carcinoma (RCC) is one of the most common malignancies worldwide, and metabolic reprogramming has a profound effect on RCC tumorigenesis. mTORC1 inhibitors are widely used in RCC treatment, yet some types of RCC cells are resistant to these compounds. Thus, clarification of the metabolic mechanism of mTORC1 inhibitors and exploration of new therapeutic approaches are urgently needed. In this study, we found that the mTORC1 pathway was hyperactive in RCC. Immunohistochemistry and western blot analysis showed that phosphorylation of the mTORC1 substrate 4EBP1 at threonine 37/46 increased in RCC tissues compared with that in normal renal tissues. It was also found that mTORC1 inhibitor everolimus suppressed glucose consumption, lactate production, and multiple catalytic enzymes involved in glycolysis in 786-O and ACHN cells, but the accumulation of HIF1α induced by CoCl2 blocked the inhibitory effect of everolimus on aerobic glycolysis. Interestingly, western blot and metabolite analysis showed that the tumor suppressor NDRG2 (N-Myc downstream regulated gene 2) was able to inhibit mTORC1 activity and cooperate with an mTOR inhibitor to decrease aerobic glycolysis in 786-O and ACHN cells. These results demonstrate that NDRG2 may potentially synergize with mTORC1 inhibitors to suppress malignant phenotype of RCC. Taken together, these data provided preclinical evidence that the combination of NDRG2 and mTORC1 inhibitors might be a promising strategy for RCC therapy.

Dual-Site Cascade Oxygen Reduction Mechanism on SnO x/Pt-Cu-Ni for Promoting Reaction Kinetics.

Designing highly active oxygen reduction reaction (ORR) catalysts is crucial to boost the fuel cell economy. Previous research has mainly focused on Pt-based alloy catalysts in which surface Pt is the solely active site and the activity improvement was challenged by the discovered scaling relationship. Herein we report a new concept of utilizing dual active sites for the ORR and demonstrate its effectiveness by synthesizing a SnO x/Pt-Cu-Ni heterojunctioned catalyst. A maximum of 40% enhancement in the apparent specific activity, which corresponds to 10-fold enhancement on interface sites, is measured compared with pure Pt-Cu-Ni. Detailed investigations suggest an altered dual-site cascade mechanism wherein the first two steps occur on SnO x sites and the remaining steps occur on adjacent Pt sites, allowing a significant decrease in the energy barrier. This study with the suggested dual-site cascade mechanism shows the potential to overcome the ORR energy barrier bottleneck to develop highly active catalysts.

MicroRNA-188-5p regulates contribution of bone marrow-derived cells to choroidal neovascularization development by targeting MMP-2/13.

Our previous investigations have shown that bone marrow-derived cells (BMCs), including mesenchymal stem cells (MSCs), contribute to the development of choroidal neovascularization (CNV) as sources of cells and angiogenic factors. Two main steps for circulating BMCs to integrate into CNV lesions are extracellular matrix remodeling and consequential cell migration. MicroRNAs (miRNAs) were found to be involved in CNV development; however, little is known about whether miRNAs regulate the contribution of BMCs to CNV. In the present study, we found that the expression of miR-188-5p was decreased in cultured hypoxic MSCs and BMCs within laser-induced CNV in mice. Matrix metalloproteinase 2 (MMP-2) and MMP-13 were both discovered as targets of miR-188-5p by bioinformatics predictions and dual-luciferase reporter system. Accordingly, increased expression of MMP-2/13 was found in hypoxic MSCs and BMCs in CNV lesions. Furthermore, miR-188-5p mimic transfection caused downregulation of MMP-2/13 in hypoxic MSCs and decreased tube formation of co-cultured vascular endothelial cells. Intravitreal injections of a miR-188-5p agomir attenuated the severity of CNV and inhibited the migration of BMCs into CNV lesions in mice. Our study suggests that miR-188-5p regulates the contribution of BMCs to CNV development by targeting MMP-2/13-mediated extracellular matrix degeneration, and miR-188-5p serves as a therapeutic target to treat CNV-related diseases.

Improving CT detection sensitivity for nodal metastases in oesophageal cancer with combination of smaller size and lymph node axial ratio.

OBJECTIVES: To investigate the value of CT with inclusion of smaller lymph node (LN) sizes and axial ratio to improve the sensitivity in diagnosis of regional lymph node metastases in oesophageal squamous cell carcinoma (OSCC). METHODS: The contrast-enhanced multidetector row spiral CT (MDCT) multiplanar reconstruction images of 204 patients with OSCC were retrospectively analysed. The long-axis and short-axis diameters of the regional LNs were measured and axial ratios were calculated (short-axis/long-axis diameters). Nodes were considered round if the axial ratio exceeded the optimal LN axial ratio, which was determined by receiver operating characteristic analysis. RESULTS: A positive predictive value (PPV) exceeding 50% is needed. This was achieved only with LNs larger than 9 mm in short-axis diameter, but nodes of this size were rare (sensitivity 37.3%, specificity 96.4%, accuracy 85.8%). If those round nodes (axial ratio exceeding 0.66 ) between 7 mm and 9 mm in size were considered metastases as well, it might improve the sensitivity to 67.2% with a PPV of 63.9% (specificity 91.6%, accuracy 87.2%). CONCLUSION: Combination of a smaller size and axial ratio for LNs in MDCT as criteria improves the detection sensitivity for LN metastases in OSCC. KEY POINTS: • CT is widely used to assess metastatic lymph nodes. • CT has low sensitivity in detecting metastases using conventional criteria. • Diagnostic sensitivity of CT was improved by using lymph node axial ratio. • New diagnostic criteria provide greater diagnostic confidence with PPVs exceeding 50%. • New diagnostic criteria may help clinicians assess patients with oesophageal cancer.

A Novel Ship-Tracking Method for GF-4 Satellite Sequential Images.

The geostationary remote sensing satellite has the capability of wide scanning, persistent observation and operational response, and has tremendous potential for maritime target surveillance. The GF-4 satellite is the first geostationary orbit (GEO) optical remote sensing satellite with medium resolution in China. In this paper, a novel ship-tracking method in GF-4 satellite sequential imagery is proposed. The algorithm has three stages. First, a local visual saliency map based on local peak signal-to-noise ratio (PSNR) is used to detect ships in a single frame of GF-4 satellite sequential images. Second, the accuracy positioning of each potential target is realized by a dynamic correction using the rational polynomial coefficients (RPCs) and automatic identification system (AIS) data of ships. Finally, an improved multiple hypotheses tracking (MHT) algorithm with amplitude information is used to track ships by further removing the false targets, and to estimate ships’ motion parameters. The algorithm has been tested using GF-4 sequential images and AIS data. The results of the experiment demonstrate that the algorithm achieves good tracking performance in GF-4 satellite sequential images and estimates the motion information of ships accurately.

NDRG2 overexpression suppresses hepatoma cells survival during metabolic stress through disturbing the activation of fatty acid oxidation.

Because of the high nutrient consumption and inadequate vascularization, solid tumor constantly undergoes metabolic stress during tumor development. Oncogenes and tumor suppressor genes participated in cancer cells' metabolic reprogramming. N-Myc downstream regulated gene 2 (NDRG2) is a recently identified tumor suppressor gene, but its function in cancer metabolism, particularly during metabolic stress, remains unclear. In this study, we found that NDRG2 overexpression significantly reduced hepatoma cell proliferation and enhanced cell apoptosis under glucose limitation. Moreover, NDRG2 overexpression aggravated energy imbalance and oxidative stress by decreasing the intracellular ATP and NADPH generation and increasing ROS levels. Strikingly, NDRG2 inhibited the activation of fatty acid oxidation (FAO), which preserves ATP and NADPH purveyance in the absence of glucose. Finally, mechanistic investigation showed that NDRG2 overexpression suppressed the glucose-deprivation induced AMPK/ACC pathway activation in hepatoma cells, whereas the expression of a constitutively active form of AMPK abrogated glucose-deprivation induced AMPK activation and cell apoptosis. Thus, as a negative regulator of AMPK, NDRG2 disturbs the induction of FAO genes by glucose limitation, leading to dysregulation of ATP and NADPH, and thus reduces the tolerance of hepatoma cells to glucose limitation.

Targeting of Discoidin Domain Receptor 2 (DDR2) Prevents Myofibroblast Activation and Neovessel Formation During Pulmonary Fibrosis.

Idiopathic pulmonary fibrosis (IPF) is a lethal human disease with short survival time and few treatment options. Herein, we demonstrated that discoidin domain receptor 2 (DDR2), a receptor tyrosine kinase that predominantly transduces signals from fibrillar collagens, plays a critical role in the induction of fibrosis and angiogenesis in the lung. In vitro cell studies showed that DDR2 can synergize the actions of both transforming growth factor (TGF)-ß and fibrillar collagen to stimulate lung fibroblasts to undergo myofibroblastic changes and vascular endothelial growth factor (VEGF) expression. In addition, we confirmed that late treatment of the injured mice with specific siRNA against DDR2 or its kinase inhibitor exhibited therapeutic efficacy against lung fibrosis. Thus, this study not only elucidated novel mechanisms by which DDR2 controls the development of pulmonary fibrosis, but also provided candidate target for the intervention of this stubborn disease.

A Newly Identified Missense Mutation in FARS2 Causes Autosomal-Recessive Spastic Paraplegia.

Hereditary spastic paraplegia (HSP) is a clinically and genetically heterogeneous group of neurodegenerative disorders characterized by spasticity of the lower limbs due to pyramidal tract dysfunction. Here, we report that a missense homozygous mutation c.424G>T (p.D142Y) in the FARS2 gene, which encodes a mitochondrial phenylalanyl tRNA synthetase (mtPheRS), causes HSP in a Chinese consanguineous family by using combination of homozygous mapping and whole-exome sequencing. Immunohistochemical experiments were performed showing that the FARS2 protein was highly expressed in the Purkinje cells of rat cerebellum. The aminoacylation activity of mtPheRS was severely disrupted by the p.D142Y substitution in vitro not only in the first aminoacylation step but also in the last transfer step. Taken together, our results indicate that a missense mutation in FARS2 contributes to HSP, which has the clinical significance of the regulation of tRNA synthetases in human neurodegenerative diseases.

A Familial 14q32.32q32.33 Duplication/17p13.3 Deletion Syndrome with Facial Anomalies and Moderate Intellectual Disability.

To our knowledge, a derivative chromosome 17 formed by a subtelomeric translocation involving chromosomes 17 and 14 has not been reported before. Here, we present the clinical and molecular cytogenetic characteristics of 2 family members with a subtelomeric rearrangement involving chromosome regions 14q32.32q32.33 and 17p13.3. The patients had moderate intellectual disability, a high forehead, a broad nasal root, downslanting palpebral fissures, epicanthal folds, retrognathia, hypertelorism, wrinkled skin over the glabella and metopic suture, and mild finger clubbing. Array CGH detected a 2.52-Mb duplication of 14q32.32q32.33 (103,805,680-106,396,479) and a 1.2-Mb deletion of 17p13.3 (87,009-1,298,869) confirmed to be pathogenic by quantitative PCR and loss of heterozygosity analysis of 17p13.3. The derivative chromosome 17 was inherited from a parental balanced translocation. To our knowledge, this cytogenetic aberration has not been described previously. The refinement of the genetic location will improve the knowledge of the genes responsible for this phenotype.

Macrophages promote vasculogenesis of retinal neovascularization in an oxygen-induced retinopathy model in mice.

To investigate the role of macrophages in oxygen-induced retinal neovascularization (NV) in mice, particularly the involvement of bone marrow-derived cells (BMCs) and the underlying mechanisms, BMCs from green fluorescent protein (GFP) transgenic mice were transplanted into postnatal day (P) 1 mice after irradiation. The mice were exposed to 75 % oxygen from P7 to P12 to initiate oxygen-induced retinopathy (OIR). The macrophages were depleted by injection of clodronate-liposomes (lip) intraperitoneally. The eyes were collected at P12 and P17. Retinal flatmounts and histopathological cross-sections were performed to analyze the severity of retinal NV and BMC recruitment. BMCs immunopositive for CD31 (PECAM-1; endothelial cell marker) and α-SMA (smooth muscle cell marker) antigens were detected using a confocal microscope. Expression of vascular endothelial growth factor (VEGF) and stromal cell-derived factor-1 (SDF-1) mRNA was detected by RT-PCR. The VEGF, SDF-1, CXCR4 and CD45 protein expression was detected by western blot examination. The retinal avascular area in OIR mice at P12 was unaffected after macrophage depletion carried out twice (38.27 ± 1.92 % reduction) using clodronate-lip. The retinal avascular area and the NV area at P17 were reduced after macrophage depletion four times (79.53 ± 1.02 % reduction); these findings were supported by retinal flatmounts and histopathological cross-sections. Macrophage depletion led to significant inhibition of BMC recruitment into the NV tufts at P17, with decreased expression of retinal VEGF, SDF-1, CXCR4 and CD45. The recruited BMCs differentiated primarily into CD31-positive endothelial cells (ECs) and α-SMA-positive smooth muscle cells (SMCs). This study suggested that macrophages promoted the vasculogenesis of retinal NV, particularly the contribution of BMCs in the mouse OIR model, which might be triggered by VEGF and SDF-1 production.

Functional and clinical evidence that TAZ is a candidate oncogene in hepatocellular carcinoma.

Transcriptional co-activator with PDZ-binding motif (TAZ) has been reported to be associated with carcinogenesis. However, the cellular function of TAZ in human hepatocellular carcinoma (HCC) remains elusive. In this study, an immunohistochemistry analysis revealed that the expression of TAZ in cancer tissue samples from 180 HCC patients was significantly higher than that in adjacent normal tissues. In addition, TAZ overexpression was significantly correlated with aggressive tumor characteristics such as tumor size, TNM stage, lymph node or distant metastasis, histological differentiation, and recurrent HCC (P < 0.05). The Kaplan-Meier test showed that TAZ-positive expression was related to a poor prognosis compared to TAZ-negative expression (P < 0.05). Furthermore, the expression level of TAZ was generally correlated with the invasiveness of cancer cells. The overexpression of TAZ in the Huh7 cell line, which endogenously expresses TAZ at low levels, significantly promoted cell proliferation, migration and invasion and inhibited apoptosis, whereas RNA interference-mediated knockdown of TAZ in the highly invasive cell line MHCC-97H significantly suppressed cell proliferation, migration and invasion in vitro and tumor formation in vivo.

Nrp1, a Neuronal Regulator, Enhances DDR2-ERK-Runx2 Cascade in Osteoblast Differentiation via Suppression of DDR2 Degradation.

BACKGROUND: Osteoblastogenesis is under delicate control by multiple factors and hormones. Recent reports indicated the involvement of immunological and neuronal regulators. However, the role of neuropilin 1 (Nrp1) in osteoblastogenesis remains obscure. METHODS: Real-time PCR was carried out to detect the mRNA of osteoblastic markers, Nrp1, and discoidin domain receptor 2 (DDR2). Immunoblot was performed to test the protein of Nrp1 and DDR2. Osteogenic differentiation was evaluated by mRNA analysis of osteogenic markers, and determination of ALP activity and OCN secretion. The intercellular signaling effectors were examined by immunoblot. Immunofluorescent assays were performed to detect the localization of Nrp1 and DDR2. Half-life determination assay was executed to test the DDR2 stability. RESULTS: The expression of Nrp1 paralleled with that of DDR2 during osteoblastogensis. Nrp1 overexpression enhanced DDR2-induced stimulation of osteoblastogensis, whereas Nrp1 silencing caused attenuation. Nrp1 overexpression increased the phosphorylation of DDR2, ERK1/2 and Runx2. Nrp1 co-localized with DDR2 in the cellular membrane of differentiated MC3T3-E1. Enhanced or attenuated Nrp1 expression did not alter the mRNA transcript of DDR2. Nrp1 overexpression prolonged the half-life of DDR2 protein. CONCLUSION: Our results originally demonstrated the stimulatory role of Nrp1 in DDR2-induced osteoblast differentiation, providing molecular evidence for exploiting Nrp1 and DDR2 as targets to treat bone-related disease.

Histochemical analysis of testis specific gene 13 in human normal and malignant tissues.

Testis-specific gene 13 (TSGA13) is abundantly expressed in testis. As previous studies of TSGA13 expression pattern have all been based on mRNA analysis, it is imperative to investigate its actual protein expression. Here, we first examined TSGA13 gene tree and protein homology among species, and found that TSGA13 is relatively well conserved. Next, we detected its protein expression in normal human tissues as well as in a limited number of malignant tumors by immunohistochemistry (IHC). It was demonstrated that, in addition to testis, high expression of TSGA13 could also be observed in multiple normal tissues, including stomach, larynx, spleen, bladder, tonsil, liver and thyroid. Notably, most types of human carcinoma tissues displayed reduced expression of TSGA13 rather than their adjacent normal tissues except glioblastoma and lung cancer. Hence, the data from the current study strongly suggest the association between TSGA13 and tumor malignancy.

c-Myc-mediated epigenetic silencing of MicroRNA-101 contributes to dysregulation of multiple pathways in hepatocellular carcinoma.

UNLABELLED: The MYC oncogene is overexpressed in hepatocellular carcinoma (HCC) and has been associated with widespread microRNA (miRNA) repression; however, the underlying mechanisms are largely unknown. Here, we report that the c-Myc oncogenic transcription factor physically interacts with enhancer of zeste homolog 2 (EZH2), a core enzymatic unit of polycomb repressive complex 2 (PRC2). Furthermore, miR-101, an important tumor-suppressive miRNA in human hepatocarcinomas, is epigenetically repressed by PRC2 complex in a c-Myc-mediated manner. miR-101, in turn, inhibits the expression of two subunits of PRC2 (EZH2 and EED), thus creating a double-negative feedback loop that regulates the process of hepatocarcinogenesis. Restoration of miR-101 expression suppresses multiple malignant phenotypes of HCC cells by coordinate repression of a cohort of oncogenes, including STMN1, JUNB, and CXCR7, and further increases expression of endogenous miR-101 by inhibition of PRC2 activation. In addition, co-overexpression of c-Myc and EZH2 in HCC samples was closely associated with lower expression of miR-101 (P < 0.0001) and poorer prognosis of HCC patients (P < 0.01). CONCLUSIONS: c-Myc collaborates with EZH2-containing PRC2 complex in silencing tumor-suppressive miRNAs during hepatocarcinogenesis and provides promising therapeutic candidates for human HCC.