ERK1/2-mediated Cytoplasmic Accumulation of hnRNPK Antagonizes TRAIL-induced Apoptosis through Upregulation of XIAP in H1299 Cells

Objective Tumor necrosis factor-related apoptosis-inducing ligand(TRAIL) resistance greatly limits the clinical therapeutic efficacy of TRAIL. Elucidating the molecular mechanism underlying TRAIL resistance will be fundamental to resolving this problem. Methods Nuclear and cytoplasmic protein extraction and immunofluorescence(IF) assay were used to detect changes in heterogeneous nuclear ribonucleoprotein K(hn RNPK) localization in H1299 cells. The evaluation of cell apoptosis in cells transfected with GFP-hn RNPK, GFP-hn RNPK S284/353 A, or GFP-hn RNPK S284/353 D mutant was performed using cleaved caspase-3 antibody. The gene expression of XIAP was tested by quantitative RT-PCR. Results Previously, we reported that hn RNPK antagonized TRAIL-induced apoptosis through inhibition of PKC-mediated GSK3β phosphorylation. In this study, we further demonstrate that TRAIL treatment induces cytoplasmic accumulation of hn RNPK in H1299 cells. The hn RNPK localized in the cytoplasm has a higher capacity to antagonize TRAIL-induced apoptosis. Both ERK1/2 signaling inhibitor U0126 and ERK-phosphoacceptor-site mutant(GFP-hn RNPK S284/353A) diminish cytoplasmic accumulation of hn RNPK induced by TRAIL. Moreover, we show that XIAP is involved in hn RNPK-mediated TRAIL resistance in H1299 cells. Conclusion Taken together, these results give new insights into the understanding of the molecular mechanism associated with TRAIL resistance in lung adenocarcinoma.

YWHAZ Binds to TRIM21 but Is Not Involved in TRIM21-stimulated Osteosarcoma Cell Proliferation

Objective Osteosarcoma is the most common type of malignant bone tumor in children and adolescents. The role of E3 ligases in tumorigenesis is currently a focus in tumor research. In the present study, we investigated the role of the E3 ligase tripartite motif 21(TRIM21) in osteosarcoma cell proliferation.Methods 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide(MTT) assays were used to assess osteosarcoma cell viability. U2-OS cells stably carrying a recombinant lentivirus expressing tetracycline-regulated TRIM21 were screened. Co-immunoprecipitation was coupled with LCMS/MS analysis to identify novel interacting partners of TRIM21. Co-immunoprecipitation and bimolecular fluorescence complementation(BIFC) were performed to validate the interactions between TRIM21 and its novel partner YWHAZ. A TRIM21-ΔRING construct was generated to test the effects of TRIM21 ligase activity on YWHAZ.Results TRIM21 positively regulated osteosarcoma cell proliferation. Overexpression of TRIM21 enhanced osteosarcoma cell tolerance toward various stresses. YWHAZ protein was identified as a novel interacting partner of TRIM21 and its expression levels were negatively regulated by TRIM21. The RING domain of TRIM21 was required for TRIM21 negative regulation of YWHAZ expression. However,overexpression of YWHAZ did not affect positive regulation of osteosarcoma cell proliferation by TRIM21.Conclusion Our results further clarify the molecular mechanisms underlying the pathogenesis of osteosarcoma.

Ideal Cardiovascular Health Metrics and Coronary Artery Calcification in Northern Chinese Population:A Cross-sectional Study

Objective Coronary artery calcification(CAC) is a well-established risk predictor of coronary heart disease events and is recognized as an indicator of subclinical atherosclerosis.Methods A cross-sectional study consisting of 2999 participants aged ≥40 years from the Jidong community of Tangshan City,an industrial and modern city of China,was conducted between 2013 and 2014 to examine the association between the ideal cardiovascular health(CVH) metrics and CAC.The ideal CVH metrics were determined based on the definition of the American Heart Association(AHA).The participants were then grouped into 4 categories according to the quartiles of their CVH metric scores as follows:first quartile(0-2),second quartile(3),third quartile(4),and fourth quartile(5-7).CAC was assessed by using high-pitch dual-source CT,and patients were identified based on thresholds of 0,10,100,or 400 Agatston units,as per common practice.Results The prevalence of subclinical atherosclerosis was 15.92%,13.85%,6.76%,and 1.93%,determined by using the CAC scores at thresholds of 0,10,100,and 400 Agatston units,respectively.Compared with the group in the first quartile,the other three CVH groups had a lower odds ratio of CAC >0 after adjusting for age,sex,income level,education level,and alcohol use in the logistic regression analysis.The odds ratios in these groups were 0.86 [95% confidence interval(CI),0.63-1.17;P<0.05],0.75(95% CI,0.55-1.02;P<0.05),and 0.49(95% CI,0.35-0.69;P<0.05),respectively.These associations of CAC with the CVH metrics were consistent when different CAC cutoff scores were used(0,10,100,or 400).Conclusion The participants with more-ideal cardiovascular metrics had a lower prevalence of subclinical atherosclerosis determined according to CAC score.Maintaining an ideal cardiovascular health may be valuable in the prevention of atherosclerosis in the general population.

Protein Phosphatase 2C of Toxoplasma Gondii Interacts with Human SSRP1 and Negatively Regulates Cell Apoptosis

Objective The protozoan Toxoplasma gondii expresses large amounts of a 37 kDa Type 2C serine-threonine phosphatase,the so-called TgPP2 C which has been suggested to contribute to parasite growth regulation.Ectopic expression in mammalian cells also indicated that the enzyme could regulate growth and survival.In this study,we aimed to investigate the interaction of TgPP2 C with human SSRP1(structure-specific recognition protein 1) and the effects of TgPP2 C on cell viability.Methods The yeast two hybrid system,His-tag pull-down and co-immunoprecipitation assays were used to confirm the interaction of TgPP2 C with SSRP1 and determine the binding domain on SSRP1.The evaluation of cell apoptosis was performed using cleaved caspase-3 antibody and Annexin-V/PI kit combined with flow cytometry.Results We identified human SSRP1 as an interacting partner of TgPP2 C.The C-terminal region of SSRP1 including the amino acids 471 to 538 was specifically mapped as the region responsible for interaction with TgPP2 C.The overexpression of TgPP2 C down-regulated cell apoptosis and negatively regulated apoptosis induced by DRB,casein kinase II(CKII) inhibitor,through enhanced interaction with SSRP1.Conclusion TgPP2 C may be a parasitic factor capable of promoting cell survival through interaction with the host protein SSRP1,thereby creating a favorable environment for parasite growth.

托尼·本尼特文化政策研究的马克思主义美学价值

文化政策研究是托尼·本尼特文化治理美学的重要内容,通过将政策引入文化研究,托尼·本尼特拓展了福柯以来的文化治理概念的研究范围,进一步将文化政策与文化研究结合起来,深化了传统文化研究的实践过程。在文化政策研究中,托尼·本尼特倡导文化研究从批判性视角融入社会文化主体的形塑过程,并在文化与治理问题的思考中展现文化政策研究的现实意义,从而推动和发展了当代马克思主义美学研究的文化转向。