73 research outputs found
The diacylglycerol kinase Ī±/Atypical PKC/Ī²1 integrin pathway in SDF-1Ī± mammary carcinoma invasiveness
Diacylglycerol kinase Ī± (DGKĪ±), by phosphorylating diacylglycerol into phosphatidic acid, provides a key signal driving cell migration and matrix invasion. We previously demonstrated that in epithelial cells activation of DGKĪ± activity promotes cytoskeletal remodeling and matrix invasion by recruiting atypical PKC at ruffling sites and by promoting RCP-mediated recycling of Ī±5Ī²1 integrin to the tip of pseudopods. In here we investigate the signaling pathway by which DGKĪ± mediates SDF-1Ī±-induced matrix invasion of MDA-MB-231 invasive breast carcinoma cells. Indeed we showed that, following SDF-1Ī± stimulation, DGKĪ± is activated and localized at cell protrusion, thus promoting their elongation and mediating SDF-1Ī± induced MMP-9 metalloproteinase secretion and matrix invasion. Phosphatidic acid generated by DGKĪ± promotes localization at cell protrusions of atypical PKCs which play an essential role downstream of DGKĪ± by promoting Rac-mediated protrusion elongation and localized recruitment of Ī²1 integrin and MMP-9. We finally demonstrate that activation of DGKĪ±, atypical PKCs signaling and Ī²1 integrin are all essential for MDA-MB-231 invasiveness. These data indicates the existence of a SDF-1Ī± induced DGKĪ± - atypical PKC - Ī²1 integrin signaling pathway, which is essential for matrix invasion of carcinoma cells
Phenobarbital induction of cytochrome p-450 b,e genes is dependent on protein synthesis
Phenobarbital induces liver cytochrome P-450 b,e proteins mainly by increasing the rate of transcription of these genes. The mechanism responsible for the phenobarbital increment in the rate of transcription of cytochrome P-450 b,e genes is unknown. The objective of this study was to assess whether active protein synthesis was needed for phenobarbital to induce the liver cytochrome P-450 b,e genes. Cycloheximide (2 mg per kg, i.p.) was administered 90 min prior to a single inductive dose of phenobarbital (80 mg per kg, i.p.) and mRNAS measured at 3, 6 and 12 hr by dot-blot hybridization. While phenobarbital increased cytochrome P-450 b,e mRNAs about 12-fold at 3 hr, this induction was abolished by cycloheximide. To define whether the absence of protein synthesis in hepatocytes inhibited the phenobarbital induction of cytochrome P-450 at the transcriptional level, in vitro transcription rates using isolated nuclei were measured. After phenobarbital administration, there was about a 20-fold increment in transcriptional rate of cytochrome P-450 b,e genes. This increment was abolished by prior injection of cycloheximide. It is proposed that either preexisting regulatory proteins or transacting factors dependent on active protein synthesis participate in the regulation of liver cytochrome P-450 b,e gene transcription after phenobarbital.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/38337/1/1840080223_ftp.pd
ACYLATED AND UNACYLATED GHRELIN IMPAIR SKELETAL MUSCLE ATROPHY IN MICE.
Cachexia is a wasting syndrome associated with cancer, AIDS, and multiple sclerosis, and several
other disease states. It is characterized by weight loss, fatigue, loss of appetite and skeletal muscle
atrophy and is associated with poor patient prognosis, making it an important treatment target.
Ghrelin is a peptide hormone that stimulates growth hormone (GH) release and positive energy
balance through binding to the receptor GHSR-1a. Only acylated ghrelin (AG), but not the
unacylated form (UnAG), can bind GHSR-1a; however, UnAG and AG share several GHSR-1aindependent
biological activities. Here we investigated whether UnAG and AG could protect
against skeletal muscle atrophy in a GHSR-1a-independent manner. We found that both AG and
UnAG inhibited dexamethasone-induced skeletal muscle atrophy and atrogene expression through
PI3K\u3b2-, mTORC2-, and p38-mediated pathways in myotubes. Up-regulation of circulating UnAG
in mice impaired skeletal muscle atrophy induced by either fasting or denervation without
stimulating muscle hypertrophy and GHSR-1a-mediated activation of the GH/IGF-1 axis. In Ghsrdeficient
mice, both AG and UnAG induced phosphorylation of Akt in skeletal muscle and
impaired fasting-induced atrophy. These results demonstrate that AG and UnAG act on a common,
unidentified receptor to block skeletal muscle atrophy in a GH-independent manner
Increased diacylglycerol kinase Ī¶ expression in human metastatic colon cancer cells augments Rho GTPase activity and contributes to enhanced invasion
Five-year survival after first-ever ischaemic stroke is worse in total anterior circulation infarcts: the SINPAC cohort.
Sustained seizure freedom with adjunctive brivaracetam in patients with focal onset seizures
The maintenance of seizure control over time is a clinical priority in patients with epilepsy. The aim of this study was to assess the sustained seizure frequency reduction with adjunctive brivaracetam (BRV) in real-world practice. Patients with focal epilepsy prescribed add-on BRV were identified. Study outcomes included sustained seizure freedom and sustained seizure response, defined as a 100% and a ā„50% reduction in baseline seizure frequency that continued without interruption and without BRV withdrawal through the 12-month follow-up. Nine hundred ninety-four patients with a median age of 45 (interquartile range = 32ā56) years were included. During the 1-year study period, sustained seizure freedom was achieved by 142 (14.3%) patients, of whom 72 (50.7%) were seizure-free from Day 1 of BRV treatment. Sustained seizure freedom was maintained for ā„6, ā„9, and 12 months by 14.3%, 11.9%, and 7.2% of patients from the study cohort. Sustained seizure response was reached by 383 (38.5%) patients; 236 of 383 (61.6%) achieved sustained ā„50% reduction in seizure frequency by Day 1, 94 of 383 (24.5%) by Month 4, and 53 of 383 (13.8%) by Month 7 up to Month 12. Adjunctive BRV was associated with sustained seizure frequency reduction from the first day of treatment in a subset of patients with uncontrolled focal epilepsy
Adjunctive Brivaracetam in Focal Epilepsy: Real-World Evidence from the BRIVAracetam add-on First Italian netwoRk STudy (BRIVAFIRST)
Background: In randomized controlled trials, add-on brivaracetam (BRV) reduced seizure frequency in patients with drug-resistant focal epilepsy. Studies performed in a naturalistic setting are a useful complement to characterize the drug profile. Objective: This multicentre study assessed the effectiveness and tolerability of adjunctive BRV in a large population of patients with focal epilepsy in the context of real-world clinical practice. Methods: The BRIVAFIRST (BRIVAracetam add-on First Italian netwoRk STudy) was a retrospective, multicentre study including adult patients prescribed adjunctive BRV. Patients with focal epilepsy and 12-month follow-up were considered. Main outcomes included the rates of seizureāfreedom, seizure response (ā„ 50% reduction in baseline seizure frequency), and treatment discontinuation. The incidence of adverse events (AEs) was also considered. Analyses by levetiracetam (LEV) status and concomitant use of strong enzyme-inducing antiseizure medications (EiASMs) and sodium channel blockers (SCBs) were performed. Results: A total of 1029 patients with a median age of 45 years (33ā56) was included. At 12 months, 169 (16.4%) patients were seizure-free and 383 (37.2%) were seizure responders. The rate of seizure freedom was 22.3% in LEV-naive patients, 7.1% in patients with prior LEV use and discontinuation due to insufficient efficacy, and 31.2% in patients with prior LEV use and discontinuation due to AEs (p < 0.001); the corresponding values for ā„ 50% seizure frequency reduction were 47.9%, 29.7%, and 42.8% (p < 0.001). There were no statistically significant differences in seizure freedom and seizure response rates by use of strong EiASMs. The rates of seizure freedom (20.0% vs. 16.6%; p = 0.341) and seizure response (39.7% vs. 26.9%; p = 0.006) were higher in patients receiving SCBs than those not receiving SCBs; 265 (25.8%) patients discontinued BRV. AEs were reported by 30.1% of patients, and were less common in patients treated with BRV and concomitant SCBs than those not treated with SCBs (28.9% vs. 39.8%; p = 0.017). Conclusion: The BRIVAFIRST provided real-world evidence on the effectiveness of BRV in patients with focal epilepsy irrespective of LEV history and concomitant ASMs, and suggested favourable therapeutic combinations
HGF-Induced PKCĪ¶ Activation Increases Functional CXCR4 Expression in Human Breast Cancer Cells
The chemokine receptor CXCR4 and its ligand CXCL12 have been shown to mediate the metastasis of many malignant tumors including breast carcinoma. Interaction between hepatocyte growth factor (HGF) and the Met receptor tyrosine kinase mediates development and progression of cancers. HGF is able to induce CXCR4 expression and contributes to tumor cell invasiveness in breast carcinoma. However, the mechanism of the CXCR4 expression modulated by c-Met-HGF axis to enhance the metastatic behavior of breast cancer cells is still unclear. In this study, we found that HGF induced functional CXCR4 receptor expression in breast cancer cells. The effect of HGF was specifically mediated by PKCĪ¶ activity. After transfection with PKCĪ¶-siRNA, the phosphorylation of PKCĪ¶ and CXCR4 was abrogated in breast cancer cells. Interference with the activation of Rac1, a downstream target of HGF, prevented the HGF-induced increase in PKCĪ¶ activity and CXCR4 levels. The HGF-induced, LY294002-sensitive translocation of PKCĪ¶ from cytosol to plasma membrane indicated that HGF was capable of activating PKCĪ¶, probably via phosphoinositide (PI) 3-kinases. HGF treatment also increased MT1-MMP secretion. Inhibition of PKCĪ¶, Rac-1 and phosphatidylinositol 3-kinase may attenuate MT1-MMP expression in cells exposed to HGF. Functional manifestation of the effects of HGF revealed an increased ability for migration, chemotaxis and metastasis in MDA-MB-436 cells in vitro and in vivo. Our findings thus provided evidence that the process of HGF-induced functional CXCR4 expression may involve PI 3-kinase and atypical PKCĪ¶. Moreover, HGF may promote the invasiveness and metastasis of breast tumor xenografts in BALB/c-nu mice via the PKCĪ¶-mediated pathway, while suppression of PKCĪ¶ by RNA interference may abrogate cancer cell spreading
Reduced incidence of spontaneous mammary tumors in c3h/he mice after treatment with polyadenylate-polyuridylate.
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