UVRAG (UV radiation resistance associated) is an important regulator of mammalian macroautophagy/autophagy by interacting with BECN1, PIK3C3, and RUBCN. Phosphorylation of UVRAG by MTORC1 negatively regulates autophagosome maturation under nutrient-enriched conditions. However, how UVRAG ubiquitination is regulated is still unknown. Here we report that UVRAG is ubiquitinated by SMURF1 at lysine residues 517 and 559, which decreases the association of UVRAG with RUBCN and promotes autophagosome maturation. However, the deubiquitinase ZRANB1 specifically cleaves SMURF1-induced K29 and K33-linked polyubiquitin chains from UVRAG, thereby increasing the binding of UVRAG to RUBCN and inhibiting autophagy flux. We also demonstrate that CSNK1A1-mediated UVRAG phosphorylation at Ser522 disrupts the binding of SMURF1 to UVRAG through PPxY motif and blocks UVRAG ubiquitination-mediated autophagosome maturation. Interestingly, ZRANB1 is phosphorylated at Thr35, and Ser209 residues by CSNK1A1, and this phosphorylation activates its deubiquitinating activity. Importantly, we provide in vitro and in vivo evidence that UVRAG ubiquitination at lysine residues 517 and 559 or prevention of Ser522 phosphorylation by D4476, a CSNK1A1 inhibitor, enhances the lysosomal degradation of EGFR, which significantly inhibits hepatocellular carcinoma (HCC) growth. Furthermore, UVRAG S522 phosphorylation levels correlate with ZRANB1 T35/S209 phosphorylation levels and poor prognosis in HCC patients. These findings identify a novel molecular mechanism by which ubiquitination and phosphorylation of UVRAG regulate its function in autophagosome maturation and HCC growth, encouraging further study of their potential therapeutic implications. Abbreviations: ATG: autophagy related; BafA 1 : bafilomycin A 1 ; BECN1: beclin 1; CHX: cycloheximide; CSNK1A1/CK1α: casein kinase 1 alpha 1; CQ: chloroquine; DUB: deubiquitinase; EBSS: Earle’s balanced salt solution; EGF: epidermal growth factor; GFP: green fluorescent protein; GST: glutathione S-transferase; HBSS: Hanks balanced salts solution; HCC: hepatocellular carcinoma; MAP1LC3B/LC3: microtubule associated protein 1 light chain 3 beta; MEFs: mouse embryo fibroblasts; mRFP: monomeric red fluorescent protein; PIK3C3 / VPS34: phosphatidylinositol 3-kinase catalytic subunit type 3; PTMs: post-translational modifications; RUBCN: rubicon autophagy regulator; siRNA: small interfering RNA; SMURF1: SMAD specific E3 ubiquitin protein ligase 1; SQSTM1: sequestosome 1; Ub-AMC: ubiquitin-7-amido-4-methylcoumarin: a fluorogenic substrate; UVRAG: UV radiation resistance associated; ZRANB1/TRABID: zinc finger RANBP2-type containing 1
Our results suggest that LOC554202 may play an important role in the progression of chordoma by the direct upregulation of EZH2 and indirect promotion of RNF144B via miR-31.
OBJECTIVEHyperglycemia, inflammation, and oxidative stress are thought to be involved in the pathogenesis of cognitive decline. Dipeptidyl peptidase-4 (DPP4) is a newly identified adipokine related to these risk factors. Hence, we aimed to investigate the association between plasma DPP4 activities and mild cognitive impairment (MCI) in elderly patients with type 2 diabetes. RESEARCH DESIGN AND METHODSWe evaluated plasma DPP4 activity, inflammatory markers, and oxidative stress parameters in a cross-sectional sample of 1,160 patients with type 2 diabetes aged 60 years or older in China. MCI was diagnosed based on criteria established by the National Institute on Aging-Alzheimer's Association workgroups RESULTSPatients in the highest quartile of DPP4 activity had higher HbA 1c , interleukin 6 (IL-6), CRP, nitrotyrosine, 8-iso-PGF2a, and lower Montreal Cognitive Assessment (MoCA) scores compared with subjects in the lowest quartile (P < 0.001). In the highest DPP4 quartile, MCI risk was higher (odds ratio 3.49; 95% CI 1.97-4.57) than in the lowest quartile after adjustment for potential confounders. The risk for MCI increased more with higher levels of DPP4 activity, IL-6, CRP, nitrotyrosine, and 8-iso-PGF2a (P < 0.05), but not with higher levels of HbA 1c . CONCLUSIONSThis study shows that increased DPP4 activities are independently associated with MCI in elderly patients with type 2 diabetes. The mechanisms might be partly explained by the effect of DPP4 on inflammation and oxidative stress. These observations raise further interest in DPP4 activity for its potential effect on these MCI-related risk factors as a biological marker or even a possible therapeutic target for MCI.Type 2 diabetes is associated with an increased risk of accelerated age-related cognitive impairment and a higher incidence of dementia (1). Dementia is generally preceded by an intermediate stage, termed mild cognitive impairment (MCI), in which patients have cognitive complaints and objective disturbances on cognitive tests but in which their daily functioning is largely preserved (2). Although not all
Cancer stem cells (CSCs) have been reported to play critical roles in tumor initiation, propagation, and regeneration of cancer. Nano-size vehicles are employed to deliver drugs to target the CSCs for cancer therapy. Polymeric nanoparticles have been considered as the most efficient vehicles for drug delivery due to their excellent pharmacokinetic properties. The CSCs specific antibodies or ligands can be conjugated onto the surface or interior of nanoparticles to successfully target and finally eliminate CSCs. In this review, we focus on the approaches of polymeric nanoparticles design for loading drug, and their potential application for CSCs targeting in cancer therapy.
The combined genetic tests of JAK2 V617F, JAK2 exon 12, MPL exon 10, and CALR exon 9 help improve the diagnostic rate for BCR-ABL1-negative MPN.
BackgroundWe aimed to investigate whether miRNA-1908 is an oncogene in human glioblastoma and find the possible mechanism of miR-1908.MethodsWe investigated the growth potentials of miRNA-1908-overexpressing SW-1783 cells in vitro and in vivo. In order to identify the target molecule of miRNA-1908, a luciferase reporter assay was performed, and the corresponding downstream signaling pathway was examined using immunohistochemistry of human glioblastoma tissues. We also investigated the miRNA-1908 expression in 34 patients according to the postoperative risk of recurrence.ResultsThe overexpression of miRNA-1908 significantly promoted anchorage-independent growth in vitro and significantly increased the tumor forming potential in vivo. MiRNA-1908 significantly suppressed the luciferase activity of mRNA combined with the PTEN 3’-UTR. Furthermore, the expression levels of miRNA-1908 were significantly increased in the patients with a high risk of recurrence compared to that observed in the low-risk patients, and this higher expression correlated with a poor survival.ConclusionsmiRNA-1908 functions as an oncogene in glioblastoma by repressing the PTEN pathway. MiR-1908 is a potential new molecular marker for predicting the risk of recurrence and prognosis of glioblastoma.Electronic supplementary materialThe online version of this article (doi:10.1186/s12943-015-0423-0) contains supplementary material, which is available to authorized users.
Cancer cells metabolize different energy sources to generate biomass rapidly. The purine biosynthetic pathway was recently identified as an important source of metabolic intermediates for these processes. However, very little was known about the regulatory mechanisms of purine metabolism in hepatocellular carcinoma (HCC). We explored the role of dual-specificity tyrosine (Y) phosphorylation-regulated kinase 3 (Dyrk3) in HCC metabolism. Dyrk3 was significantly down-regulated in HCC compared with normal controls. Its introduction in HCC cells markedly suppressed tumor growth and metastasis in xenograft tumor models. Mass spectrometric analysis of metabolites suggests that the effect of Dyrk3 on HCC occurred at least partially through down-regulating purine metabolism, as evidenced by the fact that inhibiting purine synthesis reverted the HCC progression mediated by the loss of Dyrk3. We further provide evidence that this action of Dyrk3 knockdown requires nuclear receptor coactivator 3 (NCOA3), which has been shown to be a coactivator of activating transcription factor 4 (ATF4) to target purine pathway genes for transcriptional activation. Mechanistically, Dyrk3 directly phosphorylated NCOA3 at Ser-1330, disrupting its binding to ATF4 and thereby causing the inhibition of ATF4 transcriptional activity. However, the phosphorylation-resistant NCOA3-S1330A mutant has the opposite effect. Interestingly, the promoter activity of Dyrk3 was negatively regulated by ATF4, indicating a double-negative feedback loop. Importantly, levels of Dyrk3 and phospho-NCOA3-S1330 inversely correlate with the expression of ATF4 in human HCC specimens. Conclusion: Our findings not only illustrate a function of Dyrk3 in reprograming HCC metabolism by negatively regulating NCOA3/ATF4 transcription factor complex but also identify NCOA3 as a phosphorylation substrate of Dyrk3, suggesting the Dyrk3/NCOA3/ATF4 axis as a potential candidate for HCC therapy. (Hepatology 2019;70:1785-1803).D ual-specificity tyrosine (Y) phosphorylation-regulated kinase 3 (Dyrk3) is one of five members of the mammalian kinase family which includes Dyrk1A, Dyrk1B, Dyrk2, Dyrk3, and Dyrk4. (1) Although this family shares a highly conserved amino acid sequence in the catalytic domain with a Tyr-X-Tyr motif in the activation loop, the individual members are totally different in their N-terminal and C-terminal regions. Numerous studies have confirmed the critical role of Dyrk family kinases in
BackgroundChronic myeloid leukemia is a clonal myeloproliferative disorder disease in which BCR/ABL plays an important role as an oncoprotein and molecular target. Despite the success of targeted therapy using tyrosine kinase inhibitors, CML remains largely incurable, most likely due to the treatment resistance after firstly chemical therapy. So know well the unique molecular pathway of CML is very important.MethodsThe expressions of CD44 in different leukemia patients and cell lines were detected by real-time PCR and western blotting. The effects of CD44 on proliferation of K562 cells were determined using the MTT and colony formation assays, and even in a nude mouse transplantation model. Then, the cell cycle changes were detected by flow cytometric analysis and the early apoptosis of cells was detected by the annexin V/propidium iodide double-staining assay. The expressions of the cycles and apoptosis-related proteins p21, Cyclin D1 and Bcl-2 were analyzed by western blot and real-time PCR assay. Finally, the decreased nuclear accumulation of β-catenin was detected by western blotting and immunefluorescence.ResultsFirstly, we showed that CD44 expression was increased in several kinds of leukemia patients and K562 cells. By contrast, the down-regulation of CD44 resulted in decreased proliferation with a G0/G1 arrest of cell cycle in K562 cells according to the MTT assay and the flow cytometric analysis. And no significant induction of both the early and late phases of apoptosis was shown by the annexin V-FITC and PI staining. During this process, p21 and cyclin D1 are the major causes for cell cycle arrest. In addition, we found CD44 down-regulation decreased the expression of β-catenin and increased the expression of phosphorylated β-catenin. The instability of Wnt/β-catenin pathway induced by increased expression of p-β-catenin resulted in a decreased nuclear accumulation in CD44 silenced K562 cells. In the nude mouse transplantation model, we also found the same results.ConclusionsThese results show that K562 cells depend to a greater extent on CD44 for proliferation, and CD44 down-regulation may induce a cell cycle arrest through Wnt/β-catenin pathway. CD44 blockade may be beneficial in therapy of CML.
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