alvocidib and Inflammation

Flavopiridol is a flavonoid with antiproliferative effects mediated, in part, by inhibition of cyclin-dependent kinases. Clinical manifestations in a previous Phase I trial in patients with refractory malignancies treated with a 72-h flavopiridol infusion included a proinflammatory syndrome consisting of fever, fatigue, and "local" tumor pain with concomitant alterations in plasma acute-phase reactant proteins.. The aim of this study was to determine whether the proinflammatory syndrome observed in this trial was associated with modulation of plasma cytokines.. Patients receiving flavopiridol (n = 76) had serial plasma samples drawn preinfusion and during the infusion for evaluation of interleukin (IL)-6, IL-10, IL-12, granulocyte macrophage colony-stimulating factor, basic-fibroblast growth factor, transforming growth factor-beta, and tumor necrosis factor-alpha levels by standard ELISA assays. The Wilcoxon signed rank test was used to test the significance of the difference between the baseline (time 0) plasma cytokine levels compared with the values of each subsequent data collection time points (8, 24, 48, and 72 h).. There was a significant and sustained increase in plasma IL-6 levels at all time points when compared with baseline values. Paired values were used in the statistical analysis. Median plasma (interquartile range) values of IL-6 were elevated from 15.5 (9-52) pg/ml at baseline to 23 (4-48) pg/ml (P < 0.01) at 8 h; from 15 (2-48) pg/ml at baseline to 46 (21-105) pg/ml (P < 0.001) at 24 h; from 16 (9-52) pg/ml at baseline to 61 (32-170) pg/ml (P < 0.001) at 48 h; and from 15.5 (6-48) pg/ml to 68 (40-200) pg/ml (P < 0.001) at 72 h. Significance was maintained even when adjusted for multiple comparisons. The relative increase in IL-6 concentration was dose-dependent. Moreover, IL-6 elevation had a direct correlation with flavopiridol peak plasma concentration, flavopiridol area under the curve, and plasma C-Reactive protein levels. A significant decrease in plasma granulocyte macrophage colony-stimulating factor occurred at the 8-h sampling point: 50 pg/ml (interquartile range 10-205 pg/ml, P < 0.01) when compared with baseline plasma levels and 71 pg/ml (interquartile range 5-152 pg/ml, P < 0.01). No changes in the other pro or anti-inflammatory cytokines were observed. Immunohistochemistry studies in bone marrow aspirates from a prospective group of patients in this trial demonstrated approximately 4-fold induction of IL-6 (compared with baseline), mostly in non-T cells.. Biochemical analysis of plasma in patients undergoing infusional flavopiridol found a significant dose-dependent induction of IL-6. IL-6 elevation could be a marker for the process leading to the appearance of the proinflammatory syndrome observed in patients treated with infusional flavopiridol. The mechanism(s) underlying IL-6 induction and its significance are still unknown but may influence strategies to modulate flavopiridol's clinical effects.

Topics: Antineoplastic Agents; Bone Marrow; Cyclin-Dependent Kinases; Enzyme Inhibitors; Flavonoids; Humans; Inflammation; Infusions, Intravenous; Interleukin-6; Interleukins; Neoplasms; Piperidines

Sustained neutrophilic inflammation is detrimental for cardiac repair and associated with adverse outcomes following myocardial infarction (MI). An attractive therapeutic strategy to treat MI is to reduce or remove infiltrating neutrophils to promote downstream reparative mechanisms. CDK9 inhibitor compounds enhance the resolution of neutrophilic inflammation; however, their effects on cardiac repair/regeneration are unknown. We have devised a cardiac injury model to investigate inflammatory and regenerative responses in larval zebrafish using heartbeat-synchronised light-sheet fluorescence microscopy. We used this model to test two clinically approved CDK9 inhibitors, AT7519 and flavopiridol, examining their effects on neutrophils, macrophages and cardiomyocyte regeneration. We found that AT7519 and flavopiridol resolve neutrophil infiltration by inducing reverse migration from the cardiac lesion. Although continuous exposure to AT7519 or flavopiridol caused adverse phenotypes, transient treatment accelerated neutrophil resolution while avoiding these effects. Transient treatment with AT7519, but not flavopiridol, augmented wound-associated macrophage polarisation, which enhanced macrophage-dependent cardiomyocyte number expansion and the rate of myocardial wound closure. Using cdk9-/- knockout mutants, we showed that AT7519 is a selective CDK9 inhibitor, revealing the potential of such treatments to promote cardiac repair/regeneration.

Topics: Animals; Cyclin-Dependent Kinase 9; Flavonoids; Inflammation; Myocardium; Neutrophils; Piperidines; Pyrazoles; Regeneration; Zebrafish; Zebrafish Proteins

Rapid joint clearance of small molecule drugs is the major limitation of current clinical approaches to osteoarthritis and its subtypes, including post-traumatic osteoarthritis (PTOA). Particulate systems such as nano/microtechnology could provide a potential avenue for improved joint retention of small molecule drugs. One drug of interest for PTOA treatment is flavopiridol, which inhibits cyclin-dependent kinase 9 (CDK9). Herein, polylactide-co-glycolide microparticles encapsulating flavopiridol were formulated, characterized, and evaluated as a strategy to mitigate PTOA-associated inflammation through the inhibition of CDK9. Characterization of the microparticles, including the drug loading, hydrodynamic diameter, stability, and release profile was performed. The mean hydrodynamic diameter of flavopiridol particles was ∼15 µm, indicating good syringeability and low potential for phagocytosis. The microparticles showed no cytotoxicity in-vitro, and drug activity was maintained after encapsulation, even after prolonged exposure to high temperatures (60 °C). Flavopiridol-loaded microparticles or blank (unloaded) microparticles were administered by intraarticular injection in a rat knee injury model of PTOA. We observed significant joint retention of flavopiridol microparticles compared to the soluble flavopiridol, confirming the sustained release behavior of the particles. Matrix metalloprotease (MMP) activity, an indicator of joint inflammation, was significantly reduced by flavopiridol microparticles 3 days post-injury. Histopathological analysis showed that flavopiridol microparticles reduced PTOA severity 28 days post-injury. Taken altogether, this work demonstrates a promising biomaterial platform for sustained small molecule drug delivery to the joint space as a therapeutic measure for post-traumatic osteoarthritis. STATEMENT OF SIGNIFICANCE: Post-traumatic osteoarthritis (PTOA) begins with the deterioration of subchondral bone and cartilage after acute injuries. In spite of the prevalence of PTOA and its associated financial and psychological burdens, therapeutic measures remain elusive. A number of small molecule drugs are now under investigation to replace FDA-approved palliative measures, including cyclin-dependent kinase 9 (CDK9) inhibitors which work by targeting early inflammatory programming after injury. However, the short half-life of these drugs is a major hurdle to their success. Here, we show that biomaterial encapsulation of Flavopirido

Topics: Animals; Biocompatible Materials; Cartilage, Articular; Cyclin-Dependent Kinase 9; Flavonoids; Inflammation; Injections, Intra-Articular; Osteoarthritis; Piperidines; Rats

Fungal keratitis is a serious infectious keratopathy related to fungal virulence and excessive inflammatory responses. Autophagy exhibits a potent ability to resolve inflammation during fungal infection. This study aimed to investigate the protective function of flavopiridol in

Topics: Animals; Antifungal Agents; Aspergillosis; Aspergillus fumigatus; Autophagy; Cytokines; Eye Infections, Fungal; Inflammation; Keratitis; Mice; Mice, Inbred C57BL

Atherosclerotic coronary artery disease (CAD) is one of the most prevalent diseases worldwide. Atherosclerosis was considered to be the single most important contributor to CAD. In this study, a distinct serum protein expression pattern in CAD patients was demonstrated by proteomic analysis with two-dimensional gel electrophoresis coupled with mass spectrometry. In particular, CDK9 was found to be highly elevated in serum, monocytes and artery plaque samples of CAD patients. Furthermore, there was high infiltration of CD14+ monocytes/macrophages within artery plaques correlated with the expression of CDK9. Moreover, Flavopiridol (CDK9 inhibitor) could inhibit THP-1 cell (monocytic acute leukemia cell line) proliferation by targeting CDK9. Altogether, These findings indicate that CDK9 represent an important role for inflammation in the pathogenesis of atherosclerosis. It may be a potential biomarker of atherosclerotic inflammation and offer insights into the pathophysiology and targeted therapy for atherosclerotic CAD.

Topics: Aged; Apoptosis; Atherosclerosis; Biomarkers; Cell Cycle; Cell Line, Tumor; Cell Proliferation; Cells, Cultured; Coronary Artery Disease; Cyclin-Dependent Kinase 9; Female; Flavonoids; Gene Expression; Humans; Immunohistochemistry; Inflammation; Male; Middle Aged; Monocytes; Piperidines; Protein Kinase Inhibitors; Proteomics; Reverse Transcriptase Polymerase Chain Reaction

The host innate immune response is the first line of defense against pathogens and is orchestrated by the concerted expression of genes induced by microbial stimuli. Deregulated expression of these genes is linked to the initiation and progression of diseases associated with exacerbated inflammation. We identified topoisomerase 1 (Top1) as a positive regulator of RNA polymerase II transcriptional activity at pathogen-induced genes. Depletion or chemical inhibition of Top1 suppresses the host response against influenza and Ebola viruses as well as bacterial products. Therapeutic pharmacological inhibition of Top1 protected mice from death in experimental models of lethal inflammation. Our results indicate that Top1 inhibition could be used as therapy against life-threatening infections characterized by an acutely exacerbated immune response.

Topics: Animals; Azepines; Camptothecin; DNA Topoisomerases, Type I; Ebolavirus; Flavonoids; Gene Expression Regulation; HEK293 Cells; Hemorrhagic Fever, Ebola; Host-Pathogen Interactions; Humans; Immunity, Innate; Inflammation; Influenza A virus; Interferon-beta; Mice; Mice, Inbred C57BL; Piperidines; Positive Transcriptional Elongation Factor B; RNA Polymerase II; Sendai virus; Staphylococcal Infections; Staphylococcus aureus; Topoisomerase I Inhibitors; Topotecan; Transcription, Genetic; Triazoles

Neutrophilic inflammation is tightly regulated and subsequently resolves to limit tissue damage and promote repair. When the timely resolution of inflammation is dysregulated, tissue damage and disease results. One key control mechanism is neutrophil apoptosis, followed by apoptotic cell clearance by phagocytes such as macrophages. Cyclin-dependent kinase (CDK) inhibitor drugs induce neutrophil apoptosis in vitro and promote resolution of inflammation in rodent models. Here we present the first in vivo evidence, using pharmacological and genetic approaches, that CDK9 is involved in the resolution of neutrophil-dependent inflammation. Using live cell imaging in zebrafish with labelled neutrophils and macrophages, we show that pharmacological inhibition, morpholino-mediated knockdown and CRISPR/cas9-mediated knockout of CDK9 enhances inflammation resolution by reducing neutrophil numbers via induction of apoptosis after tailfin injury. Importantly, knockdown of the negative regulator La-related protein 7 (LaRP7) increased neutrophilic inflammation. Our data show that CDK9 is a possible target for controlling resolution of inflammation.

Topics: Animals; Apoptosis; CRISPR-Cas Systems; Cyclin-Dependent Kinase 9; Disease Models, Animal; Flavonoids; Gene Knockdown Techniques; Inflammation; Macrophages; Neutrophils; Piperidines; Protein Kinase Inhibitors; Pyrazoles; Ribonucleoproteins; Zebrafish; Zebrafish Proteins

Cyclin-dependent kinase 9 (CDK-9) controls the activation of primary inflammatory response genes. The purpose of this study was to determine whether CDK-9 inhibition protects cartilage from the catabolic effects of proinflammatory cytokines.. Human chondrocytes were challenged with different proinflammatory stimuli (interleukin-1β [IL-1β], lipopolysaccharides, and tumor necrosis factor α) in the presence or absence of either the CDK-9 inhibitor flavopiridol or small interfering RNA (siRNA). The expression of messenger RNA (mRNA) for inflammatory mediator genes, catabolic genes, and anabolic genes were determined by real-time quantitative reverse transcription-polymerase chain reaction (qRT-PCR) analysis. Cartilage explants were incubated for 6 days with IL-1β in the presence or absence of flavopiridol. Cartilage matrix degradation was assessed by the release of glycosaminoglycan (GAG) and cleaved type II collagen (COL2A) peptides.. CDK-9 inhibition by flavopiridol or knockdown by siRNA effectively suppressed the induction of mRNA for inducible nitric oxide synthase by all 3 proinflammatory stimuli. Results from NF-κB-targeted PCR array analysis showed that flavopiridol suppressed IL-1β induction of a broad range of inflammatory mediator genes (59 of 67 tested). CDK-9 inhibition also suppressed the induction of catabolic genes (matrix metalloproteinase 1 [MMP-1], MMP-3, MMP-9, MMP-13, ADAMTS-4, and ADAMTS-5), but did not affect the basal expression of anabolic genes (COL2A, aggrecan, and cartilage oligomeric matrix protein) and housekeeping genes. Flavopiridol had no apparent short-term cytotoxicity, as assessed by G6PDH activity. Finally, in IL-1β-treated cartilage explants, flavopiridol reduced the release of the matrix degradation product GAG and cleaved COL2A peptides, but did not affect long-term chondrocyte viability.. CDK-9 activity is required for the primary inflammatory response in chondrocytes. Flavopiridol suppresses the induction of inflammatory mediator genes and catabolic genes to protect cartilage from the deleterious effects of proinflammatory cytokines, without affecting cell viability and functions.

Topics: ADAM Proteins; ADAMTS4 Protein; ADAMTS5 Protein; Adult; Aged; Aged, 80 and over; Cartilage, Articular; Cells, Cultured; Chondrocytes; Collagen Type II; Cyclin-Dependent Kinase 9; Cytokines; Flavonoids; Glycosaminoglycans; Humans; In Vitro Techniques; Inflammation; Interleukin-1beta; Lipopolysaccharides; Matrix Metalloproteinases; Middle Aged; Piperidines; Procollagen N-Endopeptidase; Protein Kinase Inhibitors; RNA, Small Interfering; Tumor Necrosis Factor-alpha

The cell-cycle inhibitor flavopiridol has been shown to improve recovery from spinal cord injury in animal models. However, the systemic dose of flavopiridol has side-effects and the mechanism of action is not clear. This study aimed to develop a strategy for the local delivery of flavopiridol and investigate its mechanisms of action. Poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) were used for the sustained delivery of flavopiridol. The spinal cord was right-hemisectioned and NPs were delivered into the injury site. Transparent spinal cord technology was used for the three-dimensional observation of anterograde tracing. The results showed that flavopiridol NPs had a sustained release of up to 3 days in vitro. Flavopiridol NPs significantly decreased inflammatory factor synthesis by astrocytes, including TNF-α, IL-1β, and IL-6, while the IL-10 expression was elevated. In vivo study demonstrated that flavopiridol NPs decreased cell-cycle activation, inflammatory expression and glial scarring, and facilitated neuronal survival and regeneration. The cavitation volume was decreased by ~90%. Administration of flavopiridol NPs also improved the motor recovery of injured animals. These findings demonstrated that local delivery of flavopiridol in PLGA NPs improves recovery from spinal cord injury by inhibiting astrocyte growth and inflammatory factor synthesis.

Topics: Animals; Astrocytes; Behavior, Animal; Cell Cycle Proteins; Cell Proliferation; Cells, Cultured; Drug Delivery Systems; Female; Flavonoids; Gene Expression Regulation; Glial Fibrillary Acidic Protein; Inflammation; Inflammation Mediators; Lactic Acid; Microtubule-Associated Proteins; Nanoparticles; Neurons; Piperidines; Polyglycolic Acid; Polylactic Acid-Polyglycolic Acid Copolymer; Rats, Sprague-Dawley; Recovery of Function; Spinal Cord Injuries; Wound Healing

The cyclin-dependent kinase (CDK) inhibitor flavopiridol is currently being tested in clinical trials as anticancer drug. Beyond its cell death-inducing action, we hypothesized that flavopiridol affects inflammatory processes. Therefore, we elucidated the action of flavopiridol on leukocyte-endothelial cell interaction and endothelial activation in vivo and in vitro and studied the underlying molecular mechanisms.. Flavopiridol suppressed concanavalin A-induced hepatitis and neutrophil infiltration into liver tissue. Flavopiridol also inhibited tumor necrosis factor-α-induced leukocyte-endothelial cell interaction in the mouse cremaster muscle. Endothelial cells were found to be the major target of flavopiridol, which blocked the expression of endothelial cell adhesion molecules (intercellular adhesion molecule-1, vascular cell adhesion molecule-1, and E-selectin), as well as NF-κB-dependent transcription. Flavopiridol did not affect inhibitor of κB (IκB) kinase, the degradation and phosphorylation of IκBα, nuclear translocation of p65, or nuclear factor-κB (NF-κB) DNA-binding activity. By performing a cellular kinome array and a kinase activity panel, we found LIM domain kinase-1 (LIMK1), casein kinase 2, c-Jun N-terminal kinase (JNK), protein kinase C (PKC), CDK4, CDK6, CDK8, and CDK9 to be influenced by flavopiridol. Using specific inhibitors, as well as RNA interference (RNAi), we revealed that only CDK9 is responsible for the action of flavopiridol.. Our study highlights flavopiridol as a promising antiinflammatory compound and inhibition of CDK9 as a novel approach for the treatment of inflammation-associated diseases.

Topics: Animals; Cell Adhesion; Cell Communication; Cell Movement; Cells, Cultured; Chemical and Drug Induced Liver Injury; Concanavalin A; Cyclin-Dependent Kinase 9; Disease Models, Animal; E-Selectin; Endothelium, Vascular; Flavonoids; Humans; Inflammation; Intercellular Adhesion Molecule-1; Leukocytes; Male; Mice; Mice, Inbred C57BL; NF-kappa B; Piperidines; Protein Kinase Inhibitors; Vascular Cell Adhesion Molecule-1