Small ubiquitin-like modifier (SUMO) modification has emerged as an important posttranslational control of protein functions. Daxx, a transcriptional corepressor, was reported to repress the transcriptional potential of several transcription factors and target to PML oncogenic domains (PODs) via SUMO-dependent interactions. The mechanism by which Daxx binds to sumoylated factors mediating transcriptional and subnuclear compartmental regulation remains unclear. Here, we define a SUMO-interacting motif (SIM) within Daxx and show it to be crucial for targeting Daxx to PODs and for transrepression of several sumoylated transcription factors, including glucocorticoid receptor (GR). In addition, the capability of Daxx SIM to bind SUMO also controls Daxx sumoylation. We further demonstrate that arsenic trioxide-induced sumoylation of PML correlates with a change of endogenous Daxx partitioning from GR-regulated gene promoter to PODs and a relief of Daxx repression on GR target gene expression. Our results provide mechanistic insights into Daxx in SUMO-dependent transcriptional control and subnuclear compartmentalization.
Background:Molecularly targeted agents with anti-angiogenic activity, including bevacizumab, have demonstrated clinical activity in patients with advanced/metastatic hepatocellular carcinoma (HCC). This multicentre phase II study involving patients from several Asian countries sought to evaluate the safety and efficacy of bevacizumab plus capecitabine in this population.Methods:Histologically proven/clinically diagnosed advanced HCC patients received bevacizumab 7.5 mg kg–1 on day 1 and capecitabine 800 mg m–2 twice daily on days 1–14 every 3 weeks as first-line therapy.Results:A total of 45 patients were enrolled; 44 (96%) had extrahepatic metastasis and/or major vessel invasion and 30 (67%) had hepatitis B. No grade 3/4 haematological toxicity occurred. Treatment-related grade 3/4 non-haematological toxicities included diarrhoea (n=2, 4%), nausea/vomiting (n=1, 2%), gastrointestinal bleeding (n=4, 9%) and hand–foot syndrome (n=4, 9%). The overall response rate (RECIST) was 9% and the disease control rate was 52%. Overall, median progression-free survival (PFS) and overall survival (OS) were 2.7 and 5.9 months, respectively. Median PFS and OS were 3.6 and 8.2 months, respectively, for Cancer of the Liver Italian Programme (CLIP) score ⩽3 patients, and 1.4 and 3.3 months, respectively, for CLIP score 4 patients.Conclusion:The bevacizumab–capecitabine combination shows good tolerability and modest anti-tumour activity in patients with advanced HCC.
In Taiwan, elderly men were the major group suffering from IPF. Survival time was short after IPF diagnosis, and the poor survival was largely attributable to quick IPF progression after diagnosis.
Endotoxin shock is characterized by systemic hypotension, hyporeactiveness to vasoconstrictors and acute lung edema. A nitric oxide synthase (NOS) inhibitor, NG-monomethyl-L-arginine (L-NMMA) has been shown to be effective in reversing acute lung injury. In the present study, we evaluated the effects of NOS blockade by different mechanisms on the endotoxin-induced changes. In anesthetized rats, lipopolysaccharide (LPS, Klebsiella pneumoniae) was administered intravenously in a dose of 10 mg/kg. LPS caused sustained systemic hypotension accompanied by an eightfold increase of exhaled NO during an observation period of 4 h. After the experiment, the lung weight was obtained and lung tissues were taken for the determination of mRNA expressions of inducible NOS (iNOS), interleukin-1beta (IL-1beta) and tumor necrosis factor-alpha-(TNF-alpha). Histological examination of the lungs was also performed. In the control group injected with saline solution, mRNA expressions of iNOS, IL-1beta and TNF-alpha were absent. Four hours after LPS, the mRNA expressions of iNOS and IL-1beta were still significantly enhanced, but TNF-alpha was not discernibly expressed. LPS also caused a twofold increase in lung weight. Pathological examination revealed endothelial damage and interstitial edema. Various NOS inhibitors were given 1 h after LPS administration. These agents included Nomega-nitro-L-arginine methyl ester (L-NAME, 10 mg/kg), a constitutive NOS and iNOS inhibitor; S, S'-1,4-phenylene-bis-(1,2-ethanedinyl) bis-isothiourea dihydrobromide (1,4-PBIT, 10 mg/kg), a relatively specific iNOS inhibitor, and dexamethasone (3 mg/kg), an inhibitor of iNOS expression. These NOS inhibitors all effectively reversed the systemic hypotension, reduced the exhaled NO concentration and prevented acute lung injury. The LPS-induced mRNA expressions of iNOS and IL-1beta were also significantly depressed by these NOS inhibitors. Our results suggest that NO production through the iNOS pathway is responsible for endotoxin-induced lung injury. Certain cytokines such as IL-1beta are possibly involved. These changes are minimized by NOS inhibitors through different mechanisms.
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