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1.
Drugs ; 83(3): 249-263, 2023 Feb.
Article in English | MEDLINE | ID: mdl-36692805

ABSTRACT

OBJECTIVE: We aimed to investigate whether ibuprofen use, compared with other non-selective non-steroidal anti-inflammatory drugs (ns-NSAIDs), cyclooxygenase-2 inhibitors (COX-2i) or paracetamol, increases the risk of coronavirus disease 2019 (COVID-19) diagnosis or hospitalisation. DESIGN: A prevalent user and active comparator cohort study. SETTING: Two US claims databases (Open Claims and PharMetrics Plus) mapped to the Observational Medical Outcomes Partnership Common Data Model. PARTICIPANTS: Insured patients with a history of osteoarthritis or back pain and receiving ibuprofen, other ns-NSAIDs, COX-2i or paracetamol between 1 November, 2019 and 31 January, 2020 (study enrolment window 1) or between 1 February, 2020 and 31 October, 2020 (study enrolment window 2). MAIN OUTCOME MEASURES: Large-scale propensity score matching and empirical calibration were used to minimise confounding. Incidence and hazard ratios of COVID-19 diagnosis and hospitalisation according to drug/s use were estimated and pooled in the same study period across data sources using a fixed-effects meta-analysis. Index treatment episode was the primary risk evaluation window, censored at the time of discontinuation. RESULTS: A total of 633,562 and 1,063,960 participants were included in periods 1 and 2, respectively, for the ibuprofen versus ns-NSAIDs comparison, 311,669 and 524,470 for ibuprofen versus COX-2i, and 492,002 and 878,598 for ibuprofen versus paracetamol. Meta-analyses of empirically calibrated hazard ratios revealed no significantly differential risk of COVID-19 outcomes in users of ibuprofen versus any of the other studied analgesic classes: hazard ratios were 1.13 (0.96-1.33) for the ibuprofen-ns-NSAIDs comparison, 1.03 (0.83-1.28) for the ibuprofen-COX-2i comparison and 1.13 (0.74-1.73) for ibuprofen-paracetamol comparison on COVID-19 diagnosis in the February 2020-October 2020 window. Similar hazard ratios were found on COVID-19 hospitalisation and across both study periods. CONCLUSIONS: In patients with osteoarthritis or back pain, we found no differential risks of incident COVID-19 diagnosis or COVID-19 hospitalisation for ibuprofen users compared with other ns-NSAIDs, COX-2i or paracetamol. Our findings support regulatory recommendations that NSAIDs, including ibuprofen, should be prescribed as indicated in the same way as before the COVID-19 pandemic, especially for those who rely on ibuprofen or NSAIDs to manage chronic arthritis or musculoskeletal pain symptoms.


Subject(s)
COVID-19 , Osteoarthritis , Humans , Anti-Inflammatory Agents, Non-Steroidal/therapeutic use , Ibuprofen/therapeutic use , Acetaminophen/therapeutic use , COVID-19 Testing , Cohort Studies , Pandemics , Osteoarthritis/diagnosis , Osteoarthritis/drug therapy , Cyclooxygenase 2 Inhibitors/adverse effects , Back Pain/diagnosis , Back Pain/drug therapy , Back Pain/chemically induced
2.
PLoS One ; 15(11): e0241044, 2020.
Article in English | MEDLINE | ID: mdl-33147288

ABSTRACT

The aim of this systematic review and meta-analysis was to conduct a comprehensive assessment of the evidence on the efficacy and safety of oral dydrogesterone versus micronized vaginal progesterone (MVP) for luteal phase support. Embase and MEDLINE were searched for studies that evaluated the effect of luteal phase support with daily administration of oral dydrogesterone (20 to 40 mg) versus MVP capsules (600 to 800 mg) or gel (90 mg) on pregnancy or live birth rates in women undergoing fresh-cycle IVF (protocol registered at PROSPERO [CRD42018105949]). Individual participant data (IPD) were extracted for the primary analysis where available and aggregate data were extracted for the secondary analysis. Nine studies were eligible for inclusion; two studies had suitable IPD (full analysis sample: n = 1957). In the meta-analysis of IPD, oral dydrogesterone was associated with a significantly higher chance of ongoing pregnancy at 12 weeks of gestation (odds ratio [OR], 1.32; 95% confidence interval [CI], 1.08 to 1.61; P = 0.0075) and live birth (OR, 1.28; 95% CI, 1.04 to 1.57; P = 0.0214) compared to MVP. A meta-analysis combining IPD and aggregate data for all nine studies also demonstrated a statistically significant difference between oral dydrogesterone and MVP (pregnancy: OR, 1.16; 95% CI, 1.01 to 1.34; P = 0.04; live birth: OR, 1.19; 95% CI, 1.03 to 1.38; P = 0.02). Safety parameters were similar between the two groups. Collectively, this study indicates that a higher pregnancy rate and live birth rate may be obtained in women receiving oral dydrogesterone versus MVP for luteal phase support.


Subject(s)
Dydrogesterone/administration & dosage , Fertilization in Vitro/methods , Ovulation Induction/methods , Progesterone/administration & dosage , Progestins/administration & dosage , Administration, Intravaginal , Administration, Oral , Dydrogesterone/adverse effects , Female , Fertilization in Vitro/adverse effects , Humans , Live Birth , Luteal Phase/drug effects , Ovulation Induction/adverse effects , Pregnancy , Pregnancy Rate , Progesterone/adverse effects , Treatment Outcome
3.
Front Mol Neurosci ; 11: 368, 2018.
Article in English | MEDLINE | ID: mdl-30364204

ABSTRACT

Alterations in mitochondrial morphology and function have been linked to neurodegenerative diseases, including Parkinson disease, Alzheimer disease and Huntington disease. Metabolic defects, resulting from dysfunctional mitochondria, have been reported in patients and respective animal models of all those diseases. Spinocerebellar Ataxia Type 3 (SCA3), another neurodegenerative disorder, also presents with metabolic defects and loss of body weight in early disease stages although the possible role of mitochondrial dysfunction in SCA3 pathology is still to be determined. Interestingly, the SCA3 disease protein ataxin-3, which is predominantly localized in cytoplasm and nucleus, has also been associated with mitochondria in both its mutant and wildtype form. This observation provides an interesting link to a potential mitochondrial involvement of mutant ataxin-3 in SCA3 pathogenesis. Furthermore, proteolytic cleavage of ataxin-3 has been shown to produce toxic fragments and even overexpression of artificially truncated forms of ataxin-3 resulted in mitochondria deficits. Therefore, we analyzed the repercussions of expressing a naturally occurring N-terminal cleavage fragment of ataxin-3 and the influence of an endogenous expression of the S256 cleavage fragment in vitro and in vivo. In our study, expression of a fragment derived from calpain cleavage induced mitochondrial fragmentation and cristae alterations leading to a significantly decreased capacity of mitochondrial respiration and contributing to an increased susceptibility to apoptosis. Furthermore, analyzing mitophagy revealed activation of autophagy in the early pathogenesis with reduced lysosomal activity. In conclusion, our findings indicate that cleavage of ataxin-3 by calpains results in fragments which interfere with mitochondrial function and mitochondrial degradation processes.

4.
Curr Med Res Opin ; 31(12): 2273-85, 2015 Dec.
Article in English | MEDLINE | ID: mdl-26397380

ABSTRACT

OBJECTIVE: To assess the efficacy of fenofibrate and statin dual therapy versus a double or equivalent dose of statin monotherapy. METHODS: A systematic literature search and meta-analysis was performed for publications before 1 January 2014 in MEDLINE, Embase, and BIOSIS Previews, among others. RESULTS: The difference in percentage change from baseline was in favor of dual therapy versus a double dose of statin monotherapy for triglycerides (difference -20%; standard error [SE] 2.6%) and HDL-C (8.7%; SE 1.2%), but not for LDL-C (8.4%; SE 1.5%), non-HDL-C (2.8%; SE 1.1%), total cholesterol (4.5%; SE 1.0%) and apolipoprotein B (2.6%; SE 1.1%). For high intensity statins, the difference in percentage change from baseline was in favor of dual therapy versus equivalent statin monotherapy for triglycerides (-17%; SE 2.6%) and for HDL-C (8.7%; SE 1.9%). The difference in percentage change from baseline for LDL-C was 6% (SE 1.7%), implying a greater reduction in LDL-C with statin monotherapy. For moderate intensity statins, the difference in percentage change from baseline was in favor of dual therapy versus equivalent statin monotherapy for triglycerides (-24.2%; SE 1.2%) and HDL-C (8.2%; SE 0.9%). LDL-C decreased 2.2% (SE 1.4%) more with dual therapy. CONCLUSIONS AND IMPLICATIONS OF KEY FINDINGS: When aiming to change HDL-C or triglycerides, dual therapy is to be preferred to doubling the statin dose; conversely, doubling the statin dose is to be preferred when aiming to reduce LDL-C. If the aim is both to change HDL-C or triglycerides and to reduce LDL-C, the importance of the three outcomes may need to be weighed depending on the intensity of the statin. Combining high intensity statin therapy with fenofibrate improves the effect on HDL-C and triglycerides, but lowers the effect on LDL-C. Combining a moderate intensity statin with fenofibrate improves the effect on HDL-C and triglycerides without reducing the effect on LDL-C. There is a need for long-term randomized clinical trials to compare dual therapy versus doubling the statin dose to assess the importance of improvement in HDL-C and triglycerides versus improvement in LDL-C in terms of cardiovascular outcomes. Further, the addition of ezetimibe to statin/fenofibrate therapy may be of interest.


Subject(s)
Cholesterol/blood , Fenofibrate/analogs & derivatives , Hydroxymethylglutaryl-CoA Reductase Inhibitors/administration & dosage , Apolipoproteins B/blood , Drug Therapy, Combination , Fenofibrate/administration & dosage , Humans , Hydroxymethylglutaryl-CoA Reductase Inhibitors/therapeutic use , Randomized Controlled Trials as Topic , Triglycerides/blood
5.
Autophagy ; 11(9): 1458-70, 2015.
Article in English | MEDLINE | ID: mdl-26207339

ABSTRACT

Autophagy represents an intracellular degradation process which is involved in both regular cell homeostasis and disease settings. In recent years, the molecular machinery governing this process has been elucidated. The ULK1 kinase complex consisting of the serine/threonine protein kinase ULK1 and the adapter proteins ATG13, RB1CC1, and ATG101, is centrally involved in the regulation of autophagy initiation. This complex is in turn regulated by the activity of different nutrient- or energy-sensing kinases, including MTOR, AMPK, and AKT. However, next to phosphorylation processes it has been suggested that ubiquitination of ULK1 positively influences ULK1 function. Here we report that the inhibition of deubiquitinases by the compound WP1130 leads to increased ULK1 ubiquitination, the transfer of ULK1 to aggresomes, and the inhibition of ULK1 activity. Additionally, WP1130 can block the autophagic flux. Thus, treatment with WP1130 might represent an efficient tool to inhibit the autophagy-initiating ULK1 complex and autophagy.


Subject(s)
Autophagy/drug effects , Cyanoacrylates/pharmacology , Intracellular Signaling Peptides and Proteins/metabolism , Protein Aggregates/drug effects , Protein Serine-Threonine Kinases/metabolism , Pyridines/pharmacology , Ubiquitin-Specific Proteases/antagonists & inhibitors , Autophagy-Related Protein-1 Homolog , Green Fluorescent Proteins/metabolism , HEK293 Cells , HeLa Cells , Humans , Ubiquitination/drug effects
6.
Autophagy ; 11(9): 1471-83, 2015.
Article in English | MEDLINE | ID: mdl-26213203

ABSTRACT

Autophagy describes an intracellular process responsible for the lysosome-dependent degradation of cytosolic components. The ULK1/2 complex comprising the kinase ULK1/2 and the accessory proteins ATG13, RB1CC1, and ATG101 has been identified as a central player in the autophagy network, and it represents the main entry point for autophagy-regulating kinases such as MTOR and AMPK. It is generally accepted that the ULK1 complex is constitutively assembled independent of nutrient supply. Here we report the characterization of the ATG13 region required for the binding of ULK1/2. This binding site is established by an extremely short peptide motif at the C terminus of ATG13. This motif is mandatory for the recruitment of ULK1 into the autophagy-initiating high-molecular mass complex. Expression of a ULK1/2 binding-deficient ATG13 variant in ATG13-deficient cells resulted in diminished but not completely abolished autophagic activity. Collectively, we propose that autophagy can be executed by mechanisms that are dependent or independent of the ULK1/2-ATG13 interaction.


Subject(s)
Adaptor Proteins, Signal Transducing/deficiency , Autophagy , Mutation , Protein Serine-Threonine Kinases/metabolism , Adaptor Proteins, Signal Transducing/chemistry , Adaptor Proteins, Signal Transducing/metabolism , Amino Acid Motifs , Animals , Apoptosis Regulatory Proteins , Autophagy-Related Protein-1 Homolog , Enzyme Stability , Fibroblasts/metabolism , Heat-Shock Proteins/metabolism , Mice, Knockout , Microtubule-Associated Proteins/metabolism , Peptides/metabolism , Phagosomes/metabolism , Protein Binding , Proteolysis , Sequestosome-1 Protein
7.
BMJ ; 349: g5493, 2014 Sep 23.
Article in English | MEDLINE | ID: mdl-25249162

ABSTRACT

OBJECTIVE: To characterise failure of antibiotic treatment in primary care in the United Kingdom in four common infection classes from 1991 to 2012. DESIGN: Longitudinal analysis of failure rates for first line antibiotic monotherapies associated with diagnoses for upper and lower respiratory tract infections, skin and soft tissue infections, and acute otitis media. SETTING: Routine primary care data from the UK Clinical Practice Research Datalink (CPRD). MAIN OUTCOME MEASURES: Adjusted rates of treatment failure defined by standardised criteria and indexed to year 1 (1991=100). RESULTS: From 58 million antibiotic prescriptions in CPRD, we analysed 10,967,607 monotherapy episodes for the four indications: 4,236,574 (38.6%) for upper respiratory tract infections; 3,148,947 (28.7%) for lower respiratory tract infections; 2,568,230 (23.4%) for skin and soft tissue infections; and 1,013,856 (9.2%) for acute otitis media. In 1991, the overall failure rate was 13.9% (12.0% for upper respiratory tract infections; 16.9% for lower respiratory tract infections; 12.8% for skin and soft tissue infections; and 13.9% for acute otitis media). By 2012, the overall failure rate was 15.4%, representing an increase of 12% compared with 1991 (adjusted value indexed to first year (1991) 112, 95% confidence interval 112 to 113). The highest rate was seen in lower respiratory tract infections (135, 134 to 136). While failure rates were below 20% for most commonly prescribed antibiotics (amoxicillin, phenoxymethylpenicillin (penicillin-V), and flucloxacillin), notable increases were seen for trimethoprim in the treatment of upper respiratory tract infections (from 29.2% in 1991-95 to 70.1% in 2008-12) and for ciprofloxacin (from 22.3% in 1991-95 to 30.8% in 2008-12) and cefalexin (from 22.0% in 1991-95 to 30.8% in 2008-12) in the treatment of lower respiratory tract infections. Failure rates for broad spectrum penicillins, macrolides, and flucloxacillin remained largely stable. CONCLUSIONS: From 1991 to 2012, more than one in 10 first line antibiotic monotherapies for the selected infections were associated with treatment failure. Overall failure rates increased by 12% over this period, with most of the increase occurring in more recent years, when antibiotic prescribing in primary care plateaued and then increased.


Subject(s)
Anti-Bacterial Agents/therapeutic use , Bacterial Infections/drug therapy , Bacterial Infections/economics , Primary Health Care/statistics & numerical data , Humans , Longitudinal Studies , Otitis Media/drug therapy , Respiratory Tract Infections/drug therapy , Skin Diseases, Infectious/drug therapy , Soft Tissue Infections/drug therapy , Treatment Failure , United Kingdom
8.
J Clin Pharmacol ; 54(9): 1038-47, 2014 Sep.
Article in English | MEDLINE | ID: mdl-24691799

ABSTRACT

Simvastatin and fenofibrate are frequently co-prescribed at staggered intervals for the treatment of dyslipidemia. Since a drug-drug interaction has been reported when the two drugs are given simultaneously, it is of clinical interest to know whether the interaction differs between simultaneous and staggered combinations. A study, assessing the impact of both combinations on the interaction, was conducted with 7-day treatment regimens using simvastatin 40 mg and fenofibrate 145 mg: (A) simvastatin only (evening), (B) simvastatin and fenofibrate (both in evening), and (C) simvastatin (evening) and fenofibrate (morning). Eighty-five healthy subjects received the respective treatments in a randomized, 3-way cross-over study. The pharmacokinetics of simvastatin and the active metabolite simvastatin acid were determined. There was a limited reduction in the AUC0-24h of simvastatin acid of 21 and 29% for simultaneous and staggered combination, respectively. The geometric mean AUC0-24h ratio of simvastatin acid for the two combined dosing regimens (B/C) and 90% confidence interval were 111% (102-121). The interaction apparently had no impact on lipid markers. The findings imply that the observed pharmacokinetic interaction is unlikely clinically relevant, and support the combined use of simvastatin and fenofibrate not only given at staggered interval but also given simultaneously.


Subject(s)
Fenofibrate/administration & dosage , Fenofibrate/pharmacokinetics , Hypolipidemic Agents/administration & dosage , Hypolipidemic Agents/pharmacokinetics , Simvastatin/administration & dosage , Simvastatin/pharmacokinetics , Cholesterol/blood , Cross-Over Studies , Drug Administration Schedule , Drug Interactions , Drug Therapy, Combination , Female , Fenofibrate/blood , Humans , Hypolipidemic Agents/blood , Liver-Specific Organic Anion Transporter 1 , Male , Organic Anion Transporters/genetics , Polymorphism, Single Nucleotide , Simvastatin/blood , Triglycerides/blood
9.
Pharm Stat ; 12(6): 333-6, 2013.
Article in English | MEDLINE | ID: mdl-24136872

ABSTRACT

The European Federation of Statisticians in the Pharmaceutical Industry (EFSPI) believes access to clinical trial data should be implemented in a way that supports good research, avoids misuse of such data, lies within the scope of the original informed consent and fully protects patient confidentiality. In principle, EFSPI supports responsible data sharing. EFSPI acknowledges it is in the interest of patients that their data are handled in a strictly confidential manner to avoid misuse under all possible circumstances. It is also in the interest of the altruistic nature of patients participating in trials that such data will be used for further development of science as much as possible applying good statistical principles. This paper summarises EFSPI's position on access to clinical trial data. The position was developed during the European Medicines Agency (EMA) advisory process and before the draft EMA policy on publication and access to clinical trial data was released for consultation; however, the EFSPI's position remains unchanged following the release of the draft policy. Finally, EFSPI supports a need for further guidance to be provided on important technical aspects relating to re-analyses and additional analyses of clinical trial data, for example, multiplicity, meta-analysis, subgroup analyses and publication bias.


Subject(s)
Access to Information , Clinical Trials as Topic , Drug Industry , Confidentiality , Europe , Humans , Informed Consent
10.
Sci Signal ; 6(260): ra7, 2013 Jan 29.
Article in English | MEDLINE | ID: mdl-23362240

ABSTRACT

The V600E mutation in the kinase BRAF is frequently detected in melanomas and results in constitutive activation of BRAF, which then promotes cell proliferation by the mitogen-activated protein kinase signaling pathway. Although the BRAFV600E kinase inhibitor vemurafenib has remarkable antitumor activity in patients with BRAFV600E-mutated melanoma, its effects are limited by the onset of drug resistance. We found that exposure of melanoma cell lines with the BRAFV600E mutation to vemurafenib decreased the abundance of antiapoptotic proteins and induced intrinsic mitochondrial apoptosis. Vemurafenib-treated melanoma cells showed increased cytosolic concentration of calcium, a potential trigger for endoplasmic reticulum (ER) stress, which can lead to apoptosis. Consistent with an ER stress-induced response, vemurafenib decreased the abundance of the ER chaperone protein glucose-regulated protein 78, increased the abundance of the spliced isoform of the transcription factor X-box binding protein 1 (XBP1) (which transcriptionally activates genes involved in ER stress responses), increased the phosphorylation of the translation initiation factor eIF2α (which would be expected to inhibit protein synthesis), and induced the expression of ER stress-related genes. Knockdown of the ER stress response protein activating transcription factor 4 (ATF4) significantly reduced vemurafenib-induced apoptosis. Moreover, the ER stress inducer thapsigargin prevented invasive growth of tumors formed from vemurafenib-sensitive melanoma cells in vivo. In melanoma cells with low sensitivity or resistance to vemurafenib, combination treatment with thapsigargin augmented or induced apoptosis. Thus, thapsigargin or other inducers of ER stress may be useful in combination therapies to overcome vemurafenib resistance.


Subject(s)
Apoptosis/drug effects , Endoplasmic Reticulum Stress/drug effects , Indoles/pharmacology , Melanoma/metabolism , Protein Kinase Inhibitors/pharmacology , Sulfonamides/pharmacology , Activating Transcription Factor 4/genetics , Activating Transcription Factor 4/metabolism , Amino Acid Substitution , Animals , Apoptosis/genetics , Cell Line, Tumor , Chick Embryo , DNA-Binding Proteins/genetics , DNA-Binding Proteins/metabolism , Endoplasmic Reticulum Stress/genetics , Female , Gene Knockdown Techniques , Humans , Male , Melanoma/drug therapy , Melanoma/genetics , Melanoma/pathology , Mutation, Missense , Proto-Oncogene Proteins B-raf/genetics , Proto-Oncogene Proteins B-raf/metabolism , Regulatory Factor X Transcription Factors , Transcription Factors/genetics , Transcription Factors/metabolism , Vemurafenib , X-Box Binding Protein 1
11.
Brain ; 134(Pt 7): 1925-42, 2011 Jul.
Article in English | MEDLINE | ID: mdl-21653538

ABSTRACT

Mutant ataxin-3 is aberrantly folded and proteolytically cleaved in spinocerebellar ataxia type 3. The C-terminal region of the protein includes a polyglutamine stretch that is expanded in spinocerebellar ataxia type 3. Here, we report on the analysis of an ataxin-3 mutant mouse that has been obtained by gene trap integration. The ataxin-3 fusion protein encompasses 259 N-terminal amino acids including the Josephin domain and an ubiquitin-interacting motif but lacks the C-terminus with the polyglutamine stretch, the valosin-containing protein binding region and part of the ubiquitin-interacting motif 2. Homozygous ataxin-3 mutant mice were viable and showed no apparent anatomical defects at birth. However, at the age of 9 months, homozygous and heterozygous mutant mice revealed significantly altered behaviour and progressing deficits of motor coordination followed by premature death at ∼12 months. At this time, prominent extranuclear protein aggregates and neuronal cell death was found in mutant mice. This was associated with disturbances of the endoplasmic reticulum-mediated unfolded protein response, consistent with the normal role of ataxin-3 in endoplasmic reticulum homeostasis. Thus, the ataxin-3 gene trap model provides evidence for a contribution of the non-polyglutamine containing ataxin-3 N-terminus, which mimics a calpain fragment that has been observed in spinocerebellar ataxia type 3. Consistent with the disease in humans, gene trap mice develop cytoplasmic inclusion bodies and implicate impaired unfolded protein response in the pathogenesis of spinocerebellar ataxia type 3.


Subject(s)
Brain/ultrastructure , Endoplasmic Reticulum/pathology , Inclusion Bodies/pathology , Machado-Joseph Disease/etiology , Machado-Joseph Disease/pathology , Nuclear Proteins/chemistry , Ribosomes/pathology , Transcription Factors/chemistry , Analysis of Variance , Animals , Ataxin-3 , Body Weight/genetics , Brain/pathology , Cells, Cultured , Disease Models, Animal , Embryo, Mammalian , Endoplasmic Reticulum/genetics , Endoplasmic Reticulum/ultrastructure , Fibroblasts/drug effects , Fibroblasts/ultrastructure , Gene Expression Regulation/genetics , In Situ Nick-End Labeling/methods , Inclusion Bodies/genetics , Inclusion Bodies/ultrastructure , Locomotion/genetics , Machado-Joseph Disease/genetics , Machado-Joseph Disease/physiopathology , Mice , Mice, Inbred C57BL , Mice, Transgenic , Microscopy, Immunoelectron/methods , Models, Biological , Motor Activity/genetics , Mutation/genetics , Nuclear Proteins/genetics , Peptide Fragments/genetics , Psychomotor Performance/physiology , Ribosomes/genetics , Ribosomes/ultrastructure , Transcription Factors/genetics , beta-Galactosidase/metabolism
12.
FASEB J ; 25(9): 3250-61, 2011 Sep.
Article in English | MEDLINE | ID: mdl-21659556

ABSTRACT

The protein kinase inhibitor staurosporine is one of the most potent and frequently used proapoptotic stimuli, although its mechanism of action is poorly understood. Here, we show that staurosporine as well as its analog 7-hydroxystaurosporine (UCN-01) not only trigger the classical mitochondrial apoptosis pathway but, moreover, activate an additional novel intrinsic apoptosis pathway. Unlike conventional anticancer drugs, staurosporine and UCN-01 induced apoptosis in a variety of tumor cells overexpressing the apoptosis inhibitors Bcl-2 and Bcl-x(L). Furthermore, activation of this novel intrinsic apoptosis pathway by staurosporine did not rely on Apaf-1 and apoptosome formation, an essential requirement for the mitochondrial pathway. Nevertheless, as demonstrated in caspase-9-deficient murine embryonic fibroblasts, human lymphoma cells, and chicken DT40 cells, staurosporine-induced apoptosis was essentially mediated by caspase-9. Our results therefore suggest that, in addition to the classical cytochrome c/Apaf-1-dependent pathway of caspase-9 activation, staurosporine can induce caspase-9 activation and apoptosis independently of the apoptosome. Since staurosporine derivatives have proven efficacy in clinical trials, activation of this novel pathway might represent a powerful target to induce apoptosis in multidrug-resistant tumor cells.


Subject(s)
Antineoplastic Agents/pharmacology , Apoptosis/drug effects , Apoptotic Protease-Activating Factor 1/metabolism , Caspase 9/metabolism , Staurosporine/pharmacology , Apoptosis/physiology , Apoptotic Protease-Activating Factor 1/genetics , Cell Line, Tumor , Cytochromes c/genetics , Cytochromes c/metabolism , Gene Deletion , Gene Expression Regulation, Neoplastic/drug effects , Humans , Proto-Oncogene Proteins c-bcl-2/genetics , Proto-Oncogene Proteins c-bcl-2/metabolism , Staurosporine/analogs & derivatives , bcl-X Protein/genetics , bcl-X Protein/metabolism
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