Limb-bud and Heart (LBH) functions as a tumor suppressor of nasopharyngeal carcinoma by inducing G1/S cell cycle arrest

Blocking LBH expression causes replication stress and sensitizes triple-negative breast cancer cells to ATR inhibitor treatment

Triple-negative (ER-PR-HER2-) breast cancers (TNBC) are highly aggressive and difficult to treat. TNBC exhibit high genomic instability, which enables them to adapt and become resistant to chemo/radiation therapy, leading to rapid disease relapse and mortality. The pro-survival factors that safeguard genome integrity in TNBC cells are poorly understood. LBH is an essential mammary stem cell-specific transcription regulator in the WNT pathway that is aberrantly overexpressed in TNBC, correlating with poor prognosis. Herein, we demonstrate a novel role for LBH in promoting TNBC cell survival. Depletion of LBH in multiple TNBC cell models triggered apoptotic cell death both in vitro and in vivo and led to S-G2M cell cycle delays. Mechanistically, LBH loss causes replication stress due to DNA replication fork stalling, leading to ssDNA breaks, ɣH2AX and 53BP1 nuclear foci formation, and activation of the ATR/CHK1 DNA damage response. Notably, ATR inhibition in combination with LBH downmodulation had a synergistic effect, boosting TNBC cell killing and blocking in vivo tumor growth. Our findings demonstrate, for the first time, that LBH protects the genome integrity of cancer cells by preventing replicative stress. Importantly, they uncover new synthetic lethal vulnerabilities in TNBC that could be exploited for future multi-modal precision medicine.

Virus-Host Protein Interaction Network of the Hepatitis E Virus ORF2-4 by Mammalian Two-Hybrid Assays

Throughout their life cycle, viruses interact with cellular host factors, thereby influencing propagation, host range, cell tropism and pathogenesis. The hepatitis E virus (HEV) is an underestimated RNA virus in which knowledge of the virus-host interaction network to date is limited. Here, two related high-throughput mammalian two-hybrid approaches (MAPPIT and KISS) were used to screen for HEV-interacting host proteins. Promising hits were examined on protein function, involved pathway(s), and their relation to other viruses. We identified 37 ORF2 hits, 187 for ORF3 and 91 for ORF4. Several hits had functions in the life cycle of distinct viruses. We focused on SHARPIN and RNF5 as candidate hits for ORF3, as they are involved in the RLR-MAVS pathway and interferon (IFN) induction during viral infections. Knocking out (KO) SHARPIN and RNF5 resulted in a different IFN response upon ORF3 transfection, compared to wild-type cells. Moreover, infection was increased in SHARPIN KO cells and decreased in RNF5 KO cells. In conclusion, MAPPIT and KISS are valuable tools to study virus-host interactions, providing insights into the poorly understood HEV life cycle. We further provide evidence for two identified hits as new host factors in the HEV life cycle.

Multi-cancer analysis reveals universal association of oncogenic LBH expression with DNA hypomethylation and WNT-Integrin signaling pathways

Limb-Bud and Heart (LBH) is a developmental transcription co-factor deregulated in cancer, with reported oncogenic and tumor suppressive effects. However, LBH expression in most cancer types remains unknown, impeding understanding of its mechanistic function Here, we performed systematic bioinformatic and TMA analysis for LBH in >20 different cancer types. LBH was overexpressed in most cancers compared to normal tissues (>1.5-fold; p < 0.05), including colon-rectal, pancreatic, esophageal, liver, stomach, bladder, kidney, prostate, testicular, brain, head & neck cancers, and sarcoma, correlating with poor prognosis. The cancer types showing LBH downregulation were lung, melanoma, ovarian, cervical, and uterine cancer, while both LBH over- and under-expression were observed in hematopoietic malignancies. In cancers with LBH overexpression, the LBH locus was frequently hypomethylated, identifying DNA hypomethylation as a potential mechanism for LBH dysregulation. Pathway analysis identified a universal, prognostically significant correlation between LBH overexpression and the WNT-Integrin signaling pathways. Validation of the clinical association of LBH with WNT activation in gastrointestinal cancer cell lines, and in colorectal patient samples by IHC uncovered that LBH is specifically expressed in tumor cells with nuclear beta-catenin at the invasive front. Collectively, these data reveal a high degree of LBH dysregulation in cancer and establish LBH as pan-cancer biomarker for detecting WNT hyperactivation in clinical specimens.

ISL2 is a putative tumor suppressor whose epigenetic silencing reprograms the metabolism of pancreatic cancer

Pancreatic ductal adenocarcinoma (PDA) cells reprogram their transcriptional and metabolic programs to survive the nutrient-poor tumor microenvironment. Through in vivo CRISPR screening, we discovered islet-2 (ISL2) as a candidate tumor suppressor that modulates aggressive PDA growth. Notably, ISL2, a nuclear and chromatin-associated transcription factor, is epigenetically silenced in PDA tumors and high promoter DNA methylation or its reduced expression correlates with poor patient survival. The exogenous ISL2 expression or CRISPR-mediated upregulation of the endogenous loci reduces cell proliferation. Mechanistically, ISL2 regulates the expression of metabolic genes, and its depletion increases oxidative phosphorylation (OXPHOS). As such, ISL2-depleted human PDA cells are sensitive to the inhibitors of mitochondrial complex I in vitro and in vivo. Spatial transcriptomic analysis shows heterogeneous intratumoral ISL2 expression, which correlates with the expression of critical metabolic genes. These findings nominate ISL2 as a putative tumor suppressor whose inactivation leads to increased mitochondrial metabolism that may be exploitable therapeutically.

Exosomal LBH inhibits epithelial-mesenchymal transition and angiogenesis in nasopharyngeal carcinoma via downregulating VEGFA signaling

The limb-bud and heart (LBH) gene was reported to suppress nasopharyngeal carcinoma (NPC) progression in our previous study. Distant metastasis predominantly accounts for the unsatisfactory prognosis of NPC treatment, in which epithelial-mesenchymal transition (EMT) and tumor angiogenesis are of great significance. The roles of exosomes in mediating NPC progression have been highlighted in recent researches, and attempts have been made to explore the clinical application of NPC exosomes. Here we investigated the function of the LBH gene in NPC exosomes, and its potential mechanism. NPC xenografts were constructed, showing that vascular endothelial growth factor A (VEGFA) expression and neovascularity were attenuated by LBH overexpression, together with diminished EMT progression. NPC-derived exosomes were isolated, identified and applied for in vitro/in vivo experiments, and the exosomal distribution of LBH was elevated in exosomes derived from LBH-upregulated cells. Ectopic LBH, αB-crystallin (CRYAB) and VEGFA expression was induced by lentiviral infection or plasmid transfection to explore their functions in modulating EMT and angiogenesis in NPC. The addition of LBH+ NPC exosomes during a Matrigel plug assay in mice suppressed in vivo angiogenesis, and the treatment of human umbilical vein endothelial cells (HUVECs) with LBH+ NPC exosomes inhibited cellular proliferation, migration and tube formation. The interactions among LBH, CRYAB and VEGFA were confirmed by colocalization and fluorescence resonance energy transfer (FRET) assays, and extracellular VEGFA secretion from both HUVECs and NPC cells under the treatment with LBH+ NPC exosomes was diminished according to ELISA results. We concluded that exosomal LBH inhibits EMT progression and angiogenesis in the NPC microenvironment, and that its effects are partially implemented by modulation of VEGFA expression, secretion and related signaling. Thus, LBH could serve as a promising therapeutic target in VEGFA-focused NPC treatment.

LncRNA MIR31HG Drives Oncogenicity by Inhibiting the Limb-Bud and Heart Development Gene (LBH) during Oral Carcinoma

The miR-31 host gene (MIR31HG) encodes a long non-coding RNA (LncRNA) that harbors miR-31 in its intron 2; miR-31 promotes malignant neoplastic progression. Overexpression of MIR31HG and of miR-31 occurs during oral squamous cell carcinoma (OSCC). However, the downstream effectors modulated by MIR31HG during OSCC pathogenesis remain unclear. The present study identifies up-regulation of MIR31HG expression during the potentially premalignant disorder stage of oral carcinogenesis. The potential of MIR31HG to enhance oncogenicity and to activate Wnt and FAK was identified when there was exogenous MIR31HG expression in OSCC cells. Furthermore, OSCC cell subclones with MIR31HG deleted were established using a Crispr/Cas9 strategy. RNA sequencing data obtained from cells expressing MIR31HG, cells with MIR31HG deleted and cells with miR-31 deleted identified 17 candidate genes that seem to be modulated by MIR31HG in OSCC cells. A TCGA database algorithm pinpointed MMP1, BMP2 and Limb-Bud and Heart development (LBH) as effector genes controlled by MIR31HG during OSCC. Exogenous LBH expression decreases tumor cell invasiveness, while knockdown of LBH reverses the oncogenic suppression present in MIR31HG deletion subclones. The study provides novel insights demonstrating the contribution of the MIR31HG-LBH cascade to oral carcinogenesis.

Limb-bud and Heart (LBH) mediates proliferation, fibroblast-to-myofibroblast transition and EMT-like processes in cardiac fibroblasts

Cardiac fibrosis is an important pathological change after myocardial infarction (MI). Its progression is essential for post-MI infarct healing, during which transforming growth factor beta1 (TGF-β1) plays a critical role. Limb-bud and Heart (LBH), a newly discovered target gene of TGF-β1, was shown to promote normal cardiogenesis. αB-crystallin (CRYAB), an LBH-interacting protein, was demonstrated to be involved in TGF-β1-induced fibrosis. The roles and molecular mechanisms of LBH and CRYAB during cardiac fibrosis remain largely unexplored. In this study, we investigated the alterations of LBH and CRYAB expression in mouse cardiac tissue after MI. LBH and CRYAB were upregulated in activated cardiac fibroblasts (CFs), while in vitro TGF-β1 stimulation induced the upregulation of LBH, CRYAB, and fibrogenic genes in primary CFs of neonatal rats. The results of the ectopic expression of LBH proved that LBH accelerated CF proliferation under hypoxia, mediated the expression of CRYAB and fibrogenic genes, and promoted epithelial-mesenchymal transition (EMT)-like processes in rat CFs, while subsequent CRYAB silencing reversed the effects induced by elevated LBH expression. We also verified the protein-protein interaction (PPI) between LBH and CRYAB in fibroblasts. In summary, our work demonstrated that LBH promotes the proliferation of CFs, mediates TGF-β1-induced fibroblast-to-myofibroblast transition and EMT-like processes through CRYAB upregulation, jointly functioning in post-MI infarct healing. These findings suggest that LBH could be a promising potential target for the study of cardiac repair and cardiac fibrosis.

Overexpression of Limb Bud and Heart Alleviates Sepsis-Induced Acute Lung Injury via Inhibiting the NLRP3 Inflammasome

Objective

Sepsis is a leading cause of acute lung injury (ALI). This study attempted to investigate the effects of limb bud and heart (LBH) on the development of sepsis-induced ALI and its underlying mechanism of action.

Methods

The sepsis-induced ALI mouse model was established by cecal ligation and puncture (CLP). The lung injury score and lung wet/dry weight (W/D) ratio were used to evaluate the lung injury. In vitro, ALI was simulated by lipopolysaccharide (LPS) treatment in A549 cells. The mRNA expression of LBH, NLRP3, ASC, and proinflammatory cytokines was measured by qRT-PCR. The viability of LPS-induced A549 cells was analyzed by MTT assay. Furthermore, western blot was performed to detect the protein expression of LBH, NLRP3, and ASC. LPS-induced A549 cells were treated with MCC950 (NLRP3 inflammasome inhibitor) to confirm the effect of LBH on NLRP3 inflammasome.

Results

The mRNA and protein expression of LBH was decreased in sepsis-induced ALI. LBH overexpression reduced the lung injury score, lung W/D ratio, expression of proinflammatory cytokines, and NLRP3 inflammasome activation in sepsis-induced ALI mouse model. Additionally, LBH upregulation increased the viability, while it decreased the proinflammatory cytokine expression and NLRP3 inflammasome activation of LPS-induced A549 cells. Moreover, MCC950 reversed the promoting effects of LBH silencing on proinflammatory cytokine expression and NLRP3 inflammasome activation in LPS-induced A549 cells.

Conclusions

LBH alleviated lung injury in sepsis-induced ALI mouse model by inhibiting inflammation and NLRP3 inflammasome, and restrained the inflammation by inhibiting NLRP3 inflammasome in LPS-induced A549 cells, providing a novel therapeutic target for ALI.

Limb-bud and heart as a novel biomarker for gastric intestinal type adenocarcinoma

The present study compared the expression levels of limb-bud and heart (LBH) between gastric intestinal-type adenocarcinoma (GITA) and healthy gastric tissues; with the aim of investigating the possible effect of LBH on the prognosis of patients with GITA and to analyze the associated signaling pathways in GITA. Three Oncomine gastric datasets were utilized for the preliminary prediction of the expression levels of LBH mRNA in GITA and healthy gastric tissues. Gene expression and corresponding clinical data of 163 patients with GITA were downloaded from The Cancer Genome Atlas. Wilcoxon signed rank-sum test was used to distinguish the clinical value of LBH expression in the various clinicopathological features. Subsequently, Kaplan-Meier univariate and Cox multivariate survival analyses were performed to determine the prognostic significance of LBH expression in patients with GITA. Function enrichment analysis was conducted for the co-expression gene of LBH, defined as correlation coefficient r>0.06 and P<0.05 using Pearson's χ2 test. Bioinformatics data demonstrated that compared with that in the normal gastric mucosa, LBH mRNA expression was dramatically higher in GITA tissues (P<0.05). There were significant relationships between the differential expression levels of LBH and clinicopathological parameters in GITA patients (all p<0.05), including pathological stage T (T3-4 vs. T1-2), lymph node metastasis (no vs. yes), distant metastasis (no vs. yes), histological grade (grade 3 vs. grades 1-2) and tumor stage (stages 3-4 vs. stages 1-2). Additionally, the overall survival and disease-free survival (DFS) of patients in the high expression group were poorer compared with those in the low expression group (P<0.05). Cox multivariate survival analysis indicated that increased LBH expression was an independent predictor of poor DFS prognosis in patients with GITA (P=0.045). In summary, LBH is highly expressed in GITA, which can be used as an independent predictor of poor prognosis in patients with GITA. LBH co-expressed genes are closely associated with GITA tumor migration and metastasis.

Study of LBHD1 Expression with Invasion and Migration of Bladder Cancer

LBHD1 (C11ORF48) is one of the ten potential tumor antigens identified by immunoscreening the urinary bladder cancer cDNA library in our previous study. We suspect that its expression is associated with human bladder cancer. However, the exact correlation remains unclear. To address the potential functional relationship between LBHD1 and bladder cancer, we examined the LBHD1 expression at the mRNA and protein level in 5 different bladder cancer cell lines: J82, T24, 253J, 5637, and BLZ-211. LBHD1 high and low expressing cells were used to investigate the migration, invasion, and proliferation of bladder cancer cells following transfection of LBHD1 with siRNA and plasmids, respectively. Our experiment showed that the degree of gene expression was positively related to the migration and invasion of the cancer cells while it had little effect on cell proliferation. Knocking down LBHD1 expression with LBHD1 siRNA significantly attenuated cell migration and invasion in cultured bladder cancer cells, and overexpressing LBHD1 with LBHD1 cDNA plasmids exacerbated cell migration and invasion. Nevertheless, a difference in cell proliferation after transfection of LBHD1 siRNA and LBHD1 cDNA plasmids was not found. Our findings suggest that LBHD1 might play a role in cell migration and invasion.

Overexpression of Limb-Bud and Heart (LBH) promotes angiogenesis in human glioma via VEGFA-mediated ERK signalling under hypoxia

Background

Glioma is the most common primary malignant tumor in the central nervous system with frequent hypoxia and angiogenesis. Limb-Bud and Heart (LBH) is a highly conserved transcription cofactor that participates in embryonic development and tumorigenesis.

Methods

The conditioned media from LBH regulated human glioma cell lines and patient-derived glioma stem cells (GSCs) were used to treat the human brain microvessel endothelial cells (hBMECs). The function of LBH on angiogenesis were examined through methods of MTS assay, Edu assay, TUNEL assay, western blotting analysis, qPCR analysis, luciferase reporter assay and xenograft experiment.

Findings

Our study found for the first time that LBH was overexpressed in gliomas and was associated with a poor prognosis. LBH overexpression participated in the angiogenesis of gliomas via the vascular endothelial growth factor A (VEGFA)-mediated extracellular signal-regulated kinase (ERK) signalling pathway in human brain microvessel endothelial cells (hBMECs). Rapid proliferation of gliomas can lead to tissue hypoxia and hypoxia inducible factor-1 (HIF-1) activation, while HIF-1 can directly transcriptionally regulate the expression of LBH and result in a self-reinforcing cycle.

Interpretation

LBH may be a possible treatment target to break the vicious cycle in glioma treatment.

 

 

Elevated limb-bud and heart development (LBH) expression indicates poor prognosis and promotes gastric cancer cell proliferation and invasion via upregulating Integrin/FAK/Akt pathway

The limb-bud and heart development (LBH) gene is a highly conserved, tissue-specific transcription cofactor in vertebrates that regulates multiple key genes in embryonic development. The role of LBH in various cancer types is still controversial, and its specific role and molecular mechanism in the oncogenesis of gastric cancer (GC) remains largely unexplored. In the present study, the prognostic significance and clinicopathological characteristics of LBH in GC was determined. The LBH mRNA expression was first investigated in four independent public datasets (TCGA-STAD, GSE15459, GSE29272, and GSE62254) and then validated with our samples at the protein level. LBH was overexpressed at both the mRNA and protein levels in cancer compared with normal tissues. High LBH expression was correlated with advanced T, N, and M stages. Kaplan–Meier analysis and log-rank test indicated that higher LBH expression was statistically correlated with shorter overall survival (OS) in the public datasets and our study samples. Univariate and multivariate Cox regression analysis showed that LBH was an independent prognostic biomarker for survival in TCGA-STAD, GSE15459, GSE62254 cohorts, and our GC patients. In vitro experiments showed that knockdown of LBH can significantly inhibit the proliferation and invasion of HGC-27 cells, while overexpression of LBH can significantly enhance the proliferation and invasion of BGC-823 cells. Gene Set Enrichment Analysis (GSEA), Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomics (KEGG) indicated that high LBH expression is associated with the PI3K-Akt pathway, focal adhesion, and extracellular matrix (ECM)-receptor interaction. Western blot analysis showed that knockdown of LBH significantly inhibited the expression of integrin α5, integrin β1, p-FAK, and p-Akt. Therefore, results from the present study indicate that LBH is a potential independent prognostic biomarker and promotes proliferation and invasion of GC cells by activating the integrin/FAK/Akt pathway.

Loss of Limb-Bud-and-Heart (LBH) attenuates mammary hyperplasia and tumor development in MMTV-Wnt1 transgenic mice

WNT/β-catenin signaling plays pivotal roles in mammary development and tumorigenesis; and aberrant activation of this pathway is frequently observed in human breast cancer, correlating with poor outcome. However, the mechanisms underlying WNT-driven mammary tumorigenesis remain incompletely understood. Here, we used mouse mammary tumor virus (MMTV)-Wnt1 transgenic mice, which develop aggressive mammary adenocarcinomas, to examine whether Limb-Bud-and-Heart (LBH) - a WNT/β-catenin target transcription co-factor overexpressed in human triple-negative breast cancers with WNT pathway hyperactivation, contributes to WNT-induced tumorigenesis. We found LBH is specifically overexpressed in basal epithelial tumor cells of MMTV-Wnt1 mammary tumors reminiscent of its basal cell-restricted expression in the normal postnatal mammary gland. To determine the role of LBH in mammary tumorigenesis, we crossed MMTV-Wnt1 mice with basal epithelial-specific Keratin 14/K14-Cre;Lbh^loxP knockout mice. Mammary glands from virgin LBH-deficient MMTV-Wnt1 mice exhibited reduced hyperplasia, cell proliferation and increased apoptosis. Importantly, LBH inactivation in mammary epithelium significantly delayed tumor onset in MMTV-Wnt1 transgenic mice, with a median tumor-free survival of 32.5 weeks compared to 22.5 weeks in control LBH wild type MMTV-Wnt1 mice (p < 0.05). This data provides the first evidence that LBH plays an essential role in WNT-induced mammary tumorigenesis by promoting hyperplastic growth and tumor formation.

The Dynamic Roles of TGF-β Signalling in EBV-Associated Cancers

The transforming growth factor-β (TGF-β) signalling pathway plays a critical role in carcinogenesis. It has a biphasic action by initially suppressing tumorigenesis but promoting tumour progression in the later stages of disease. Consequently, the functional outcome of TGF-β signalling is strongly context-dependent and is influenced by various factors including cell, tissue and cancer type. Disruption of this pathway can be caused by various means, including genetic and environmental factors. A number of human viruses have been shown to modulate TGF-β signalling during tumorigenesis. In this review, we describe how this pathway is perturbed in Epstein-Barr virus (EBV)-associated cancers and how EBV interferes with TGF-β signal transduction. The role of TGF-β in regulating the EBV life cycle in tumour cells is also discussed.

In Vitro Identification of New Transcriptomic and miRNomic Profiles Associated with Pulmonary Fibrosis Induced by High Doses Everolimus: Looking for New Pathogenetic Markers and Therapeutic Targets

The administration of Everolimus (EVE), a mTOR inhibitor used in transplantation and cancer, is often associated with adverse effects including pulmonary fibrosis. Although the underlying mechanism is not fully clarified, this condition could be in part caused by epithelial to mesenchymal transition (EMT) of airway cells. To improve our knowledge, primary bronchial epithelial cells (BE63/3) were treated with EVE (5 and 100 nM) for 24 h. EMT markers (α-SMA, vimentin, fibronectin) were measured by RT-PCR. Transepithelial resistance was measured by Millicell-ERS ohmmeter. mRNA and microRNA profiling were performed by Illumina and Agilent kit, respectively. Only high dose EVE increased EMT markers and reduced the transepithelial resistance of BE63/3. Bioinformatics showed 125 de-regulated genes that, according to enrichment analysis, were implicated in collagen synthesis/metabolism. Connective tissue growth factor (CTGF) was one of the higher up-regulated mRNA. Five nM EVE was ineffective on the pro-fibrotic machinery. Additionally, 3 miRNAs resulted hyper-expressed after 100 nM EVE and able to regulate 31 of the genes selected by the transcriptomic analysis (including CTGF). RT-PCR and western blot for MMP12 and CTGF validated high-throughput results. Our results revealed a complex biological network implicated in EVE-related pulmonary fibrosis and underlined new potential disease biomarkers and therapeutic targets.

Overexpression of LBH is associated with poor prognosis in human hepatocellular carcinoma

Purpose

Limb-bud and heart (LBH) levels are correlated with adverse survival in several malignancies; however, their significance in hepatocellular carcinoma (HCC) remains unclear. The objective of this study was to determine the association between LBH status and clinical outcomes.

Methods

We selected 226 patients with HCC who were treated surgically between 2003 and 2010 at a single academic center. Immunohistochemistry (IHC) was used to detect the protein expression of LBH in HCC samples. Receiver operating characteristic (ROC) curve analysis, Spearman’s rank correlation, Kaplan–Meier plots, and the Cox proportional hazards regression model were used to analyze the data.

Results

A high expression of LBH was detected in 20 (8.8%) of 226 HCC samples. Correlation analysis demonstrated that LBH in HCC was significantly correlated with aspartate aminotransferase (AST)/alanine aminotransferase (ALT) levels and clinical stages (P<0.05). In the Kaplan–Meier analysis, the mean survival time of patients with low levels of LBH was longer than that for those with high levels of LBH (P<0.05). The 3-year overall survival rate was 20% for patients with HCC and high levels of LBH versus 67% for patients with HCC and low levels of LBH. In the multivariate analysis, AST/ALT level, clinical stage, tumor relapse, and the level of LBH were the independent prognostic factors for overall survival (P<0.05).

Conclusion

Overexpression of LBH might contribute to the development and progression of HCC. LBH could be a novel prognostic marker for HCC.

Limb-bud and Heart Overexpression Inhibits the Proliferation and Migration of PC3M Cells

Background: The limb-bud and heart gene (LBH) was discovered in the early 21st century and is specifically expressed in the mouse embryonic limb and heart development. Increasing evidences have indicated that LBH not only plays an important role in embryo development, it is also closely correlated with the occurance and progression of many tumors. However, its function in prostate cancer (PCa) is still not well understood. Here, we explored the effects of LBH on the proliferation and migration of the PCa cell line PC3M. Methods: LBH expression in tissues and cell lines of PCa was detected by immunohistochemistry and Western blotting. Lentivirus was used to transduct the LBH gene into the PC3M cells. Stable LBH-overexpressing PC3M-LBH cells and PC3M-NC control cells were obtained via puromycin screening. Cell proliferation was examined using the 3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay. Cell cycle distribution and apoptosis rate were investigated using flow cytometry. Cell migration was studied using the Transwell assay. Results: LBH expression level was down-regulated in 3 different PCa cell lines, especially in PC3M cells, compared with the normal prostate epithelial cells(RWPE-1). Cell lines of LBH-upregulated PC3M-LBH and PC3M-NC control were successfully constructed. Significantly increased LBH expression level and decreased cyclin D1 and cyclin E2 expression level was found in PC3M-LBH cells as compared to the PC3M-NC cells. The overexpression of LBH significantly inhibited PC3M cell proliferation in vitro and tumor growth in nude mice. LBH overexpression in PC3M cell, also induced cell cycle G0/G1 phase arrest and decreased the migration of PC3M cells. Conclusions: Our results reveal that LBH expression is down-regulated in the tissue and cell lines of PCa. LBH overexpression inhibits PC3M cell proliferation and tumor growth by inducing cell cycle arrest through down-regulating cyclin D1and cyclin E2 expression. LBH might be a therapeutic target and potential diagnostic marker in PCa.

Identification of core gene networks and hub genes associated with progression of non-alcoholic fatty liver disease by RNA sequencing

AIM

Non-alcoholic fatty liver disease (NAFLD) progresses because of the interaction between numerous genes. Thus, we carried out a weighted gene coexpression network analysis to identify core gene networks and key genes associated with NAFLD progression.

METHODS

We enrolled 39 patients with mild NAFLD (fibrosis stages 0-2) and 21 with advanced NAFLD (fibrosis stages 3-4). Total RNA was extracted from frozen liver biopsies, and sequenced to capture a large dynamic range of expression levels.

RESULTS

A total of 1777 genes differentially expressed between mild and advanced NAFLD (q-value <0.05) clustered into four modules. One module was enriched for genes that encode cell surface or extracellular matrix proteins, and are involved in cell adhesion, proliferation, and signaling. This module formed a scale-free network containing four hub genes (PAPLN, LBH, DPYSL3, and JAG1) overexpressed in advanced NAFLD. PAPLN is a component of the extracellular matrix, LBH and DPYSL3 are reported to be tumor suppressors, and JAG1 is tumorigenic. Another module formed a random network, and was enriched for genes that accumulate in the mitochondria. These genes were downregulated in advanced NAFLD, reflecting impaired mitochondrial function. However, the other two modules did not form unambiguous networks. KEGG analysis indicated that 71 differentially expressed genes were involved in "pathways in cancer". Strikingly, expression of half of all differentially expressed genes was inversely correlated with methylation of CpG sites (q-value <0.05). Among clinical parameters, serum type IV collagen 7 s was most strongly associated with the epigenetic status in NAFLD.

CONCLUSIONS

Newly identified core gene networks suggest that the NAFLD liver undergoes mitochondrial dysfunction and fibrosis, and acquires tumorigenic potential epigenetically. Our data provide novel insights into the pathology and etiology of NAFLD progression, and identify potential targets for diagnosis and treatment.

Triterpenoids from Ganoderma lucidum inhibit the activation of EBV antigens as telomerase inhibitors

Nasopharyngeal carcinoma (NPC) is a malignant disease that threatens the health of humans. To find effective agents for the inhibition of Epstein-Barr virus (EBV) infection, which is associated with NPC, a phytochemical investigation of Ganoderma lucidum was carried out in the present study. Five triterpenoids were identified, including ganoderic acid A (compound 1), ganoderic acid B (compound 2), ganoderol B (compound 3), ganodermanontriol (compound 4), and ganodermanondiol (compound 5), on the basis of spectroscopic analysis. An inhibition of EBV antigens activation assay was implemented to elucidate the triterpenoids from G. lucidum and potentially prevent NPC. All the triterpenoids showed significant inhibitory effects on both EBV EA and CA activation at 16 nmol. At 3.2 nmol, all the compounds moderately inhibited the activation of the two antigens. The activity of telomerase was inhibited by these triterpenoids at 10 µM. Molecular docking demonstrated that compound 1 was able to inhibit telomerase as a ligand. In addition, the physicochemical properties of these compounds were calculated to elucidate their drug-like properties. These results provided evidence for the application of these triterpenoids and whole G. lucidum in the treatment of NPC.

Regulation of the Cell Cycle and Inflammatory Arthritis by the Transcription Cofactor LBH Gene

Rheumatoid arthritis (RA) fibroblast-like synoviocytes (FLS) display unique aggressive behavior, invading the articular cartilage and promoting inflammation. Using an integrative analysis of RA risk alleles, the transcriptome and methylome in RA FLS, we recently identified the limb bud and heart development (LBH) gene as a key dysregulated gene in RA and other autoimmune diseases. Although some evidence suggests that LBH could modulate the cell cycle, the precise mechanism is unknown and its impact on inflammation in vivo has not been defined. Our cell cycle analysis studies show that LBH deficiency in FLS leads to S-phase arrest and failure to progress through the cell cycle. LBH-deficient FLS had increased DNA damage and reduced expression of the catalytic subunit of DNA polymerase α. Decreased DNA polymerase α was followed by checkpoint arrest due to phosphorylation of checkpoint kinase 1. Because DNA fragments can increase arthritis severity in preclinical models, we then explored the effect of LBH deficiency in the K/BxN serum transfer model. Lbh knockout exacerbated disease severity, which is associated with elevated levels of IL-1β and checkpoint kinase 1 phosphorylation. These studies indicate that LBH deficiency induces S-phase arrest that, in turn, exacerbates inflammation. Because LBH gene variants are associated with type I diabetes mellitus, systemic lupus erythematosus, RA, and celiac disease, these results suggest a general mechanism that could contribute to immune-mediated diseases.

LBH Gene Transcription Regulation by the Interplay of an Enhancer Risk Allele and DNA Methylation in Rheumatoid Arthritis

OBJECTIVE

To identify nonobvious therapeutic targets for rheumatoid arthritis (RA), we performed an integrative analysis incorporating multiple "omics" data and the Encyclopedia of DNA Elements (ENCODE) database for potential regulatory regions. This analysis identified the limb bud and heart development (LBH) gene, which has risk alleles associated with RA/celiac disease and lupus, and can regulate cell proliferation in RA. We identified a novel LBH transcription enhancer with an RA risk allele (rs906868 G [Ref]/T) 6 kb upstream of the LBH gene with a differentially methylated locus. The confluence of 3 regulatory elements, rs906868, an RA differentially methylated locus, and a putative enhancer, led us to investigate their effects on LBH regulation in fibroblast-like synoviocytes (FLS).

METHODS

We cloned the 1.4-kb putative enhancer with either the rs906868 Ref allele or single-nucleotide polymorphism (SNP) variant into reporter constructs. The constructs were methylated in vitro and transfected into cultured FLS by nucleofection.

RESULTS

We found that both variants increased transcription, thereby confirming the region's enhancer function. Unexpectedly, the transcriptional activity of the Ref risk allele was significantly lower than that of the SNP variant and is consistent with low LBH levels as a risk factor for aggressive FLS behavior. Using RA FLS lines with a homozygous Ref or SNP allele, we confirmed that homozygous Ref lines expressed lower LBH messenger RNA levels than did the SNP lines. Methylation significantly reduced enhancer activity for both alleles, indicating that enhancer function is dependent on its methylation status.

CONCLUSION

This study shows how the interplay between genetics and epigenetics can affect expression of LBH in RA.

Molecular dissection of valproic acid effects in acute myeloid leukemia identifies predictive networks

Histone deacetylase inhibitors (HDACIs) like valproic acid (VPA) display activity in leukemia models and induce tumor-selective cytotoxicity against acute myeloid leukemia (AML) blasts. As there are limited data on HDACIs effects, we aimed to dissect VPA effects in vitro using myeloid cell lines with the idea to integrate findings with in vivo data from AML patients treated with VPA additionally to intensive chemotherapy (n = 12). By gene expression profiling we identified an in vitro VPA response signature enriched for genes/pathways known to be implicated in cell cycle arrest, apoptosis, and DNA repair. Following VPA treatment in vivo, gene expression changes in AML patients showed concordant results with the in vitro VPA response despite concomitant intensive chemotherapy. Comparative miRNA profiling revealed VPA-associated miRNA expression changes likely contributing to a VPA-induced reversion of deregulated gene expression. In addition, we were able to define markers predicting VPA response in vivo such as CXCR4 and LBH. These could be validated in an independent cohort of VPA and intensive chemotherapy treated AML patients (n = 114) in which they were inversely correlated with relapse-free survival. In summary, our data provide new insights into the molecular mechanisms of VPA in myeloid blasts, which might be useful in further advancing HDAC inhibition based treatment approaches in AML.

Downregulated expression of LBH mRNA in peripheral blood mononuclear cells from patients with systemic lupus erythematosus

We performed a gene expression study to explore whether expression levels of LBH contribute to the pathogenesis of systemic lupus erythematosus (SLE) and are associated with the genome-wide association study-identified SNP (rs7579944 and rs906868) and the SLE Disease Activity Index (SLEDAI). Fluorescent quantitative reverse transcription polymerase chain reaction was used to examine the expression of LBH mRNA in peripheral blood mononuclear cells (PBMC) from 62 SLE patients and 69 controls. The expression levels of LBH mRNA in patients with SLE were significantly decreased compared with those in normal controls (P < 0.001). No significant differences were found between LBH mRNA expression levels and SLEDAI scores, SNP rs7579944 and rs906868. This study suggests that decreased expression of LBH mRNA may be correlated with the pathogenesis of SLE.