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Background: Invasion and metastasis remain a critical issue in cervical cancer. However, the underlying mechanism of it in cervical cancer remains unclear. The newly discovered protein, TBLR1, plays a crucial role in regulating various key cellular functions. Methods: In this study, western blot, real-time RT–PCR, immunohistochemical staining, 3D morphogenesis Matrigel culture, wound healing and Boyden chamber invasion assays, xenografted tumour model, luciferase assays, and chromatin immunoprecipitation assays were used. Results: The expression of TBLR1 in cervical cancer cell lines and tissues was significantly upregulated at both the RNA and protein levels compared with that in normal cervical cells. Statistical analysis suggested that TBLR1 as an independent prognostic factor was significantly correlated with the clinical stage, survival time and recurrence. Moreover, overexpression of TBLR1 in Hela and Siha cell lines promoted invasion in vitro and in vivo with the increases of the mesenchymal factors vimentin and fibronectin and decreases of the epithelial marker α -catenin. In contrast, RNAi-mediated knockdown of TBLR1 inhibited epithelial–mesenchymal transition in vitro and in vivo . Further study indicated that this might be mediated via the NF- κ B and Wnt/ β -Catenin signalling pathway, and involve regulation of Snail and Twist. Conclusions: The TBLR1 protein may be a prognostic marker in cervical cancer and play an important role in the invasion and metastasis of human cervical cancer.

In Toxoplasma gondii, cis-acting elements present in promoter sequences of genes that are stage-specifically regulated have been described. However, the nuclear factors that bind to these cis-acting elements and regulate promoter activities have not been identified. In the present study, we performed affinity purification, followed by proteomic analysis, to identify nuclear factors that bind to a stage-specific promoter in T. gondii. This led to the identification of several nuclear factors in T. gondii including a novel factor, designated herein as TgNF3. The N-terminal domain of TgNF3 shares similarities with the N-terminus of yeast nuclear FK506-binding protein (FKBP), known as a histone chaperone regulating gene silencing. Using anti-TgNF3 antibodies, HA-FLAG and YFP-tagged TgNF3, we show that TgNF3 is predominantly a parasite nucleolar, chromatin-associated protein that binds specifically to T. gondii gene promoters in vivo. Genome-wide analysis using chromatin immunoprecipitation followed by high-throughput sequencing (ChIP-seq) identified promoter occupancies by TgNF3. In addition, TgNF3 has a direct role in transcriptional control of genes involved in parasite metabolism, transcription and translation. The ectopic expression of TgNF3 in the tachyzoites revealed dynamic changes in the size of the nucleolus, leading to a severe attenuation of virulence in vivo. We demonstrate that TgNF3 physically interacts with H3, H4 and H2A/H2B assembled into bona fide core and nucleosome-associated histones. Furthermore, TgNF3 interacts specifically to histones in the context of stage-specific gene silencing of a promoter that lacks active epigenetic acetylated histone marks. In contrast to virulent tachyzoites, which express the majority of TgNF3 in the nucleolus, the protein is exclusively located in the cytoplasm of the avirulent bradyzoites. We propose a model where TgNF3 acts essentially to coordinate nucleolus and nuclear functions by modulating nucleosome activities during the intracellular proliferation of the virulent tachyzoites of T. gondii.

MicroRNAs (miRNAs) are important host molecules involved in human immunodeficiency virus type 1 (HIV-1) infection. Antiretroviral therapy (ART) can affect the miRNA expression profile, but differentially expressed miRNAs still remain to be identified. In this study, we used gene chips to analyze miRNA expression profiles in peripheral blood mononuclear cells from ART-naive HIV-1 patients and those receiving ART, as well as from uninfected individuals. We measured differences in miRNA expression by quantitative polymerase chain reaction (qPCR) in an expanded sample. We found significant differences in the expression of has-miR-191-5p among the three groups (P < 0.05). Furthermore, we showed that hsa-miR-191-5p has an inhibitory effect on HIV-1 replication in cell models in vitro. We identified CCR1 and NUP50 as target molecules of hsa-miR-191-5p and found that hsa-miR-191-5p inhibits the expression of CCR1 and NUP50. Knockdown of NUP50 resulted in significant inhibition of HIV-1 replication. In summary, our research shows that hsa-miR-191-5p expression is reduced in HIV-1-infected patients and acts an inhibitor of HIV-1 infection via a mechanism that may involve targeted repression of NUP50 expression.

Although messenger RNA (mRNA) translation is a fundamental biological process, it has never been imaged in real time in vivo with single-molecule precision. To achieve this, we developed nascent chain tracking (NCT), a technique that uses multi-epitope tags and antibody-based fluorescent probes to quantify protein synthesis dynamics at the single-mRNA level. NCT reveals an elongation rate of ~10 amino acids per second, with initiation occurring stochastically every ~30 seconds. Polysomes contain ~1 ribosome every 200 to 900 nucleotides and are globular rather than elongated in shape. By developing multicolor probes, we showed that most polysomes act independently; however, a small fraction (~5%) form complexes in which two distinct mRNAs can be translated simultaneously. The sensitivity and versatility of NCT make it a powerful new tool for quantifying mRNA translation kinetics.

Colorectal cancer patients often relapse after chemotherapy, owing to the survival of stem or progenitor cells referred to as cancer stem cells (CSCs). Although tumor stromal factors are known to contribute to chemoresistance, it remains not fully understood how CSCs in the hypoxic tumor microenvironment escape the chemotherapy. Here, we report that hypoxia-inducible factor (HIF-1α) and cancer-associated fibroblasts (CAFs)-secreted TGF-β2 converge to activate the expression of hedgehog transcription factor GLI2 in CSCs, resulting in increased stemness/dedifferentiation and intrinsic resistance to chemotherapy. Genetic or small-molecule inhibitor-based ablation of HIF-1α/TGF-β2−mediated GLI2 signaling effectively reversed the chemoresistance caused by the tumor microenvironment. Importantly, high expression levels of HIF-1α/TGF-β2/GLI2 correlated robustly with the patient relapse following chemotherapy, highlighting a potential biomarker and therapeutic target for chemoresistance in colorectal cancer. Our study thus uncovers a molecular mechanism by which hypoxic colorectal tumor microenvironment promotes cancer cell stemness and resistance to chemotherapy and suggests a potentially targeted treatment approach to mitigating chemoresistance.

Wu and colleagues report that under hypoxic conditions the LATS2 kinase is targeted for degradation by the SIAH2 ubiquitin ligase, leading to inhibition of the Hippo kinase cascade and activation of YAP, which promotes tumour growth. The Hippo signalling pathway plays important roles in animal development, physiology and tumorigenesis 1 , 2 , 3 . Understanding how the activity of this pathway is regulated by the cellular microenvironment remains a major challenge. Here we elucidate a molecular mechanism by which hypoxia deactivates Hippo signalling. We demonstrate that the E3 ubiquitin ligase SIAH2 stimulates YAP by destabilizing LATS2, a critical component of the Hippo pathway, in response to hypoxia. Loss of SIAH2 suppresses tumorigenesis in a LATS2-dependent manner in a xenograft mouse model. We further show that YAP complexes with HIF1α and is essential for HIF1α stability and function in tumours in vivo . LATS2 is downregulated in human breast tumours and negatively correlates with SIAH2 expression levels, indicating that the SIAH2–LATS2 pathway may have a role in human cancer. Our data uncover oxygen availability as a microenvironment signal for the Hippo pathway and have implications for understanding the regulation of Hippo signalling in tumorigenesis.

Although loss-of-function p53 alterations are widespread in many tumors, melanomas typically do not harbor TP53 mutations. This report uncovers upregulation of MDM4 as a frequent trait of melanomas that contributes to tumorigenesis by inactivating p53 signaling. MDM4 is required for growth and survival of melanoma cell lines, and compounds that can target MDM4 are effective against melanoma in vivo and against tumors resistant to BRAF-targeted therapy in vitro . The inactivation of the p53 tumor suppressor pathway, which often occurs through mutations in TP53 (encoding tumor protein 53) is a common step in human cancer. However, in melanoma—a highly chemotherapy-resistant disease— TP53 mutations are rare, raising the possibility that this cancer uses alternative ways to overcome p53-mediated tumor suppression. Here we show that Mdm4 p53 binding protein homolog (MDM4), a negative regulator of p53, is upregulated in a substantial proportion (∼65%) of stage I–IV human melanomas and that melanocyte-specific Mdm4 overexpression enhanced tumorigenesis in a mouse model of melanoma induced by the oncogene Nras . MDM4 promotes the survival of human metastatic melanoma by antagonizing p53 proapoptotic function. Notably, inhibition of the MDM4-p53 interaction restored p53 function in melanoma cells, resulting in increased sensitivity to cytotoxic chemotherapy and to inhibitors of the BRAF (V600E) oncogene. Our results identify MDM4 as a key determinant of impaired p53 function in human melanoma and designate MDM4 as a promising target for antimelanoma combination therapy.

Despite Bridging INtegrator 1 ( BIN1 ) being the second most statistically-significant locus associated to Late Onset Alzheimer’s Disease, its role in disease pathogenesis remains to be clarified. As reports suggest a link between BIN1, Tau and extracellular vesicles, we investigated whether BIN1 could affect Tau spreading via exosomes secretion. We observed that BIN1-associated Tau-containing extracellular vesicles purified from cerebrospinal fluid of AD-affected individuals are seeding-competent. We showed that BIN1 over-expression promotes the release of Tau via extracellular vesicles in vitro as well as exacerbation of Tau pathology in vivo in PS19 mice. Genetic deletion of Bin1 from microglia resulted in reduction of Tau secretion via extracellular vesicles in vitro , and in decrease of Tau spreading in vivo in male, but not female, mice, in the context of PS19 background. Interestingly, ablation of Bin1 in microglia of male mice resulted in significant reduction in the expression of heat-shock proteins, previously implicated in Tau proteostasis. These observations suggest that BIN1 could contribute to the progression of AD-related Tau pathology by altering Tau clearance and promoting release of Tau-enriched extracellular vesicles by microglia.

Growing up on a dairy farm protects children from allergy, hay fever, and asthma. A mechanism linking exposure to this endotoxin (bacterial lipopolysaccharide)–rich environment with protection has remained elusive. Here we show that chronic exposure to low-dose endotoxin or farm dust protects mice from developing house dust mite (HDM)–induced asthma. Endotoxin reduced epithelial cell cytokines that activate dendritic cells (DCs), thus suppressing type 2 immunity to HDMs. Loss of the ubiquitin-modifying enzyme A20 in lung epithelium abolished the protective effect. A single-nucleotide polymorphism in the gene encoding A20 was associated with allergy and asthma risk in children growing up on farms. Thus, the farming environment protects from allergy by modifying the communication between barrier epithelial cells and DCs through A20 induction.

A distinct subset of thoracic sarcomas with undifferentiated rhabdoid morphology and SMARCA4 inactivation has recently been described, and potential targeted therapy for SMARC -deficient tumors is emerging. We sought to validate the clinicopathological features of SMARCA4 -deficient thoracic sarcomas. Clinicopathological information was gathered for 40 undifferentiated thoracic tumors with rhabdoid morphology (mediastinum ( n =18), lung ( n =14), pleura ( n =8)). Thymic carcinomas ( n =11) were used as a comparison group. Immunohistochemistry included BRG1 ( SMARCA4 ), BRM ( SMARCA2 ), INI-1 ( SMARCB1 ), pan-cytokeratin, desmin, NUT, S-100 protein, TTF1, CD34, and SOX2. BRG1 loss was present in 12 of 40 rhabdoid thoracic tumors (30%): 7 of 18 in mediastinum (39%), 2 of 8 in pleura (25%), and 3 of 14 in lung (21%). All BRG1-deficient tumors tested for BRM ( n =8) showed concomitant loss. All thymic carcinomas showed retained BRG1 and INI-1. Morphologically, tumors with BRG1 loss showed sheets of monotonous ovoid cells with indistinct cell borders, abundant eosinophilic cytoplasm, and prominent nucleoli. Scattered areas with rhabdoid morphology (ie, eccentric nuclei, dense eosinophilic cytoplasm, discohesion) were present in all the cases. SMARCA4 /BRG1-deficient sarcomas showed rare cells positive for cytokeratin in 10 cases (83%). One showed rare TTF1-positive cells. All were negative for desmin, NUT, and S-100 protein. CD34 was positive in three of five (60%) BRG1-deficient tumors tested. SOX2 was positive in all four BRG1-deficient tumors tested, and negative in all seven tested cases with retained BRG1. SMARCA4 /BRG1-deficient sarcomas occurred at median age of 59 years (range 44–76) with male predominance (9:3) and had worse 2-year survival compared with BRG1-retained tumors (12.5% vs 64.4%, P =0.02). SMARCA4 -deficient thoracic sarcomas can be identified based on their distinctive high-grade rhabdoid morphology, and the diagnosis can be confirmed by immunohistochemistry. Identification of these tumors is clinically relevant due to their aggressive behavior, poor prognosis, and potential targeted therapy.