BPTF cooperates with p50 NF-κB to promote COX-2 expression and tumor cell growth in lung cancer.

Cyclooxygenase-2 (COX-2) is overexpressed in most human cancers, but its precise regulatory mechanism in cancer cells remains unclear. The aims of this study are to discover and identify the new regulatory factors which bind to the COX-2 promoter and regulate COX-2 expression and cancer cell growth, and to elucidate the mechanisms of action of these factors in lung cancer. In this study, the COX-2 promoter-binding protein BPTF (bromodomain PHD finger transcription factor) was detected, identified and verified by biotin-streptavidin-agarose pulldown, mass spectrum analysis and chromatin immunoprecipitation (ChIP) in lung cancer cells, respectively. The expressions of COX-2 and BPTF in lung cancer cell lines, mouse tumor tissues and human clinical samples were detected by RT-PCR, Western blot and immunohistochemistry assays. The interaction of BPTF with NF-kB was analyzed by immunoprecipitation and confocal immunofluorescence assays. We discovered and identified BPTF as a new COX-2 promoter-binding protein in human lung cancer cells. Knockdown of BPTF inhibited COX-2 promoter activity and COX-2 expression in lung cancer cells in vitro and in vivo. We also found that BPTF functioned as a transcriptional regulator through its interaction with the p50 subunit of NF-kB. Knockdown of BPTF abrogated the binding of p50 to the COX-2 promoter, while the inhibition of p50 activity abolished the decreased trend of COX-2 expression and lung cancer cell proliferation caused by BPTF silencing. Moreover, we showed that the expressions of BPTF and COX-2 in tumor tissues of lung cancer patients were positively correlated, and high co-expression of BPTF and COX-2 predicted poor prognosis in lung cancer patients. Collectively, our results indicated that BPTF cooperated with p50 NF-κB to regulate COX-2 expression and lung cancer growth, suggesting that the BPTF/p50/COX-2 axis could be a potential therapeutic target for lung cancer.

p38 MAPK is Crucial for Wnt1- and LiCl-Induced Epithelial Mesenchymal Transition.

Idiopathic pulmonary fibrosis (IPF) is characterized by myofibroblast foci in lung parenchyma. Myofibroblasts are thought to originate from epithelial-to-mesenchymal transition (EMT). Wnt1 and lithium chloride (LiCl) induce EMT in alveolar epithelial cells (AECs), but the mechanisms are unclear. AECs were treated with Wnt1 and LiCl, respectively; morphological change and molecular changes of EMT, including E-cadherin, fibronectin, and vimentin, were observed. SB203580 was administrated to test the role of p38 МАРК signaling in EMT. Then AECs were treated with siRNAs targeting p38 МАРК to further test the effects of p38 МАРК, and the role was further confirmed by re-expression of p38 МАРК. At last P-catenin siRNA was used to test the role of ß-catenin in the EMT process and relationship of ß-catenin and p38 МАРК was concluded. Exposure of AECs to Wnt1 and LiCl resulted in upregulation of vimentin and fibronectin with subsequent downregulation of E-cadherin. Wnt1 and LiCl stimulated the p38 МАРК signaling pathways. Perturbing the p38 МАРК pathway either by SB203580 or through p38 МАРК siRNA blocked EMT and inhibited fibronetin synthesis, which were reversed by transfection of p38 МАРК expression plasmid. ß-catenin siRNA attenuated the EMT process and decreased p38 МАРК phosphorylation, indicating that ß-catenin is involved in the EMTrelated changes through regulation of p38 МАРК phosphorylation. These findings suggest that p38 МАРК participates in the pathogenesis of EMT through Wnt pathway and that p38 МАРК may be a novel target for IPF therapy.

Effects of Dendroaspis natriuretic peptide on delayed rectifier potassium currents and its mechanism.

Dendroaspis natriuretic peptide (DNP), a newly-described natriuretic peptide, plays an inhibitory role in smooth muscle motility of the gastrointestinal tract. However, the effect of DNP on delayed rectifier potassium currents I(K(V)) is still unclear. In this study, we sought to investigate the effect of DNP on I(K(V)) and its mechanism in gastric antral circular smooth muscle cells using the whole-cell patch-clamp technique. DNP significantly inhibited I(K(V)) in a concentration-dependent manner. LY83583 (1 micromol/l), a guanylate cyclase inhibitor, significantly impaired DNP-induced inhibition of I(K(V)). Moreover, DNP-induced inhibition in I(K(V)) was potentiated by the cyclic guanosine monophosphate (cGMP) sensitive phosphoesterase inhibitor zaparinast (0.1 micromol/l). DNP-induced inhibition of I(K(V)) was completely blocked by KT5823, an inhibitor of cGMP-dependent protein kinase G(PKG), but not affected by KT-5720, a PKA-specific inhibitor. Taken together, our results suggest that DNP inhibits I(K(V)) via the cGMP/PKG-dependent signaling axis instead of the cAMP/PKA pathway.

Inhibitory effect of dendroaspis natriuretic peptide on spontaneous contraction in gastric antral circular smooth muscles of guinea pigs.

AIM: To determine whether the natriuretic peptide receptor (NPR) is present in the stomach of guinea pigs and to investigate the effect of dendroaspis natriuretic peptide (DNP) on the gastric motility of guinea pigs and its mechanism. METHODS: The distribution of the NPR was analyzed by autoradioimmunography. The spontaneous contraction of gastric antral circular muscles of guinea pigs was recorded by a 4-channel physiograph. The whole cell patch-clamp technique was introduced to record calcium-activated potassium currents in the gastric myocytes isolated by collagenase. RESULTS: The NPR existed in the gastric fundus, gastric body, and gastric antrum of guinea pigs, and its density was largest in the gastric antrum. DNP inhibited spontaneous contraction and exhibited a dose-dependent manner. The DNP-induced inhibition was diminished by LY83583 (a guanylate cyclase inhibitor) and was potentiated by zaprinast (a cGMP-sensitive phosphoesterase inhibitor). The inhibitory effect of DNP on spontaneous contraction was also inhibited by tetraethylammonium (a non-selective potassium channel blocker); 10 nmol/L DNP increased the calcium-activated potassium currents in the gastric circular myocytes of guinea pigs. CONCLUSION: The NPR is most common in the gastric antrum of guinea pigs. DNP significantly inhibits gastric motility in the gastric antrum of guinea pigs. The inhibitory effect occurs via a cGMP-dependent pathway, and a calcium-activated potassium channel may be also involved in the relaxation induced by DNP in gastric antral circular smooth muscles.

Comparison of standard large trauma craniotomy with routine craniotormy in treatment of acute subdural hematoma.

OBJECTIVE: To compare the therapeutic effect and indication between standard large trauma craniotomy and routine craniotomy. METHODS: There were 97 patients in the standard large trauma craniotomy group and 110 patients in the routine craniotomy group. The mortality, postoperative ICP (intracranial pressure), ratio of pupil rebound, complication and results of six month follow-up after operation were compared between the two groups. RESULTS: Fifteen patients (15.6%) died in the standard large trauma craniotomy group and 30 (27.7%) in the routine craniotomy group. The postoperative mean ICP was 3.75 kPa+/-1.89 kPa in the standard large trauma craniotomy group and 5.11 kPa+/-1.57 kPa in the routine craniotomy group. The pupil rebound was found in 47 patients (61.0%) in the standard large trauma craniotomy group and in 41 patients (46.1%) in the routine craniotomy group (P<0.01). The rate of complication was lower in the standard large trauma craniotomy group, but no obvious difference in long-term therapeutic effect was found between the two groups. CONCLUSIONS: Standard large trauma craniotomy can attenuate brain hernia and the mortality of the patients with acute subdural hematoma. The incidence of complication can also be decreased. But the long term life quality of the patients can not be improved.