OBJECTIVE: To investigate the protective effect of protein kinase C (PKC) inhibitor rottlerin on rat renal vascular endothelial injury induced by lipopolysaccharide (LPS). METHODS: Rat renal microvascular endothelial cells cultured for 3-6 generations were divided into three groups according to random number table: blank control group in which cells were not challenged, LPS group in which cells were only stimulated by LPS 10 mg/L for 24 hours, and PKC inhibitor group in which cells were treated with PKC inhibitor rottlerin 2 μmol/L 30 minutes before LPS stimulation. The levels of tumor necrosis factor-α (TNF-α) and interleukins (IL-1β, IL-8) were determined by enzyme-linked immunosorbent assay (ELISA). Monolayer permeability was determined by Transwell assay. The expressions of PKC, RhoA and vascular endothelial-cadherin (VE-cadherin) were detected by Western Blot. The morphological characteristic and distribution of F-actin was measured by laser confocal fluorescence microscope. RESULTS: Compared with blank control group, the levels of inflammatory cytokines at 24 hours after 10 mg/L LPS stimulation were significantly increased in LPS group [TNF-α (ng/L): 397.3±25.4 vs. 46.8±8.9, IL-1β (ng/L): 76.7±11.2 vs. 12.6±3.2, IL-8 (ng/L): 574.5±31.4 vs. 73.2±9.6, all P < 0.05], the permeability of endothelial cells was significantly increased (A value: 1.32±0.03 vs. 0.36±0.02, P < 0.05), while the expressions of PKC and RhoA were significantly up-regulated (PKC/β-actin: 0.88±0.02 vs. 0.61±0.03, RhoA/β-actin: 0.96±0.01 vs. 0.49±0.03, both P < 0.05), VE-cadherin expression was significantly down-regulated (VE-cadherin/β-actin: 0.51±0.01 vs. 0.72±0.04, P < 0.05), and the F-actin distribution disorder had obvious stress fiber formation. Compared with LPS group, the levels of inflammatory cytokines were significantly lowered in PKC inhibitor group [TNF-α (ng/L): 127.4±14.6 vs. 397.3±25.4, IL-1β(ng/L): 43.2±7.8 vs. 76.7±11.2, IL-8 (ng/L): 212.7±18.2 vs. 574.5±31.4, all P < 0.05], the permeability of endothelial cells was significantly decreased (A value: 0.81±0.02 vs. 1.32±0.03, P < 0.05), the expressions of PKC and RhoA were significantly down-regulated (PKC/β-actin: 0.44±0.03 vs. 0.88±0.02, RhoA/β-actin: 0.63±0.05 vs. 0.96±0.01, both P < 0.05), the VE-cadherin expression was significantly up-regulated (VE-cadherin/β-actin: 0.69±0.03 vs. 0.51±0.01, P < 0.05), and the F-actin remodeling and stress fiber formation were significantly reduced. CONCLUSIONS PKC inhibitor could significantly attenuate the damage of vascular endothelial barrier induced by LPS, and plays an important role in endothelial cell barrier.
Acute Kidney Injury/prevention & control* ; Animals ; Endothelium, Vascular/drug effects* ; Interleukin-1beta ; Lipopolysaccharides/toxicity* ; Protein Kinase C/antagonists & inhibitors* ; Protein Kinase Inhibitors/pharmacology* ; Random Allocation ; Rats

Accumulating data have revealed that abnormal activity of the mTOR (mammalian target of rapamycin) pathway plays an important role in epileptogenesis triggered by various factors. We previously reported that pretreatment with perifosine, an inhibitor of Akt (also called protein kinase B), abolishes the rapamycin-induced paradoxical increase of S6 phosphorylation in a rat model induced by kainic acid (KA). Since Akt is an upstream target in the mTOR signaling pathway, we set out to determine whether perifosine has a preventive effect on epileptogenesis. Here, we explored the effect of perifosine on the model of temporal epilepsy induced by KA in rats and found that pretreatment with perifosine had no effect on the severity or duration of the KA-induced status epilepticus. However, perifosine almost completely inhibited the activation of p-Akt and p-S6 both acutely and chronically following the KA-induced status epilepticus. Perifosine pretreatment suppressed the KA-induced neuronal death and mossy fiber sprouting. The frequency of spontaneous seizures was markedly decreased in rats pretreated with perifosine. Accordingly, rats pretreated with perifosine showed mild impairment in cognitive functions. Collectively, this study provides novel evidence in a KA seizure model that perifosine may be a potential drug for use in anti-epileptogenic therapy.
Animals ; Anticonvulsants ; pharmacology ; Brain ; drug effects ; pathology ; Convulsants ; toxicity ; Disease Models, Animal ; Epilepsy, Temporal Lobe ; chemically induced ; pathology ; Kainic Acid ; toxicity ; Male ; Neurons ; drug effects ; pathology ; Phosphorylcholine ; analogs & derivatives ; pharmacology ; Protein Kinase Inhibitors ; pharmacology ; Proto-Oncogene Proteins c-akt ; antagonists & inhibitors ; Rats ; Rats, Sprague-Dawley ; Status Epilepticus ; chemically induced ; pathology

PURPOSE: Rearrangement of the proto-oncogene rearranged during transfection (RET) has been newly identified potential driver mutation in lung adenocarcinoma. Clinically available tyrosine kinase inhibitors (TKIs) target RET kinase activity, which suggests that patients with RET fusion genes may be treatable with a kinase inhibitor. Nevertheless, the mechanisms of resistance to these agents remain largely unknown. Thus, the present study aimed to determine whether epidermal growth factor (EGF) and hepatocyte growth factor (HGF) trigger RET inhibitor resistance in LC-2/ad cells with CCDC6-RET fusion genes. MATERIALS AND METHODS: The effects of EGF and HGF on the susceptibility of a CCDC6-RET lung cancer cell line to RET inhibitors (sunitinib, E7080, vandetanib, and sorafenib) were examined. RESULTS: CCDC6-RET lung cancer cells were highly sensitive to RET inhibitors. EGF activated epidermal growth factor receptor (EGFR) and triggered resistance to sunitinib, E7080, vandetanib, and sorafenib by transducing bypass survival signaling through ERK and AKT. Reversible EGFR-TKI (gefitinib) resensitized cancer cells to RET inhibitors, even in the presence of EGF. Endothelial cells, which are known to produce EGF, decreased the sensitivity of CCDC6-RET lung cancer cells to RET inhibitors, an effect that was inhibited by EGFR small interfering RNA (siRNA), anti-EGFR antibody (cetuximab), and EGFR-TKI (Iressa). HGF had relatively little effect on the sensitivity to RET inhibitors. CONCLUSION: EGF could trigger resistance to RET inhibition in CCDC6-RET lung cancer cells, and endothelial cells may confer resistance to RET inhibitors by EGF. E7080 and other RET inhibitors may provide therapeutic benefits in the treatment of RET-positive lung cancer patients.
Adenocarcinoma/drug therapy/*genetics ; Cell Line, Tumor ; Cetuximab/pharmacology ; Drug Resistance, Neoplasm/drug effects/*genetics ; Epidermal Growth Factor/metabolism/*pharmacology ; *Gene Rearrangement ; Hepatocyte Growth Factor/*pharmacology ; Humans ; Indoles/pharmacology ; Lung Neoplasms/drug therapy/*genetics ; MAP Kinase Signaling System ; *Mutation ; Niacinamide/analogs & derivatives/pharmacology ; Phenylurea Compounds/pharmacology ; Piperidines/pharmacology ; Protein Kinase Inhibitors/therapeutic use ; Proto-Oncogene Proteins c-ret/*antagonists & inhibitors/genetics ; Pyrroles/pharmacology ; Quinazolines/pharmacology ; RNA, Small Interfering/pharmacology ; Receptor, Epidermal Growth Factor/genetics/metabolism ; Signal Transduction/drug effects ; fms-Like Tyrosine Kinase 3/metabolism

Swelling-activated chloride currents (ICl.swell) are thought to play a role in several physiologic and pathophysiologic processes and thus represent a target for therapeutic approaches. However, the mechanism of ICl.swell regulation remains unclear. In this study, we used the whole-cell patch-clamp technique to examine the role of protein kinase C (PKC) in the regulation of ICl.swell in human atrial myocytes. Atrial myocytes were isolated from the right atrial appendages of patients undergoing coronary artery bypass and enzymatically dissociated. ICl.swell was evoked in hypotonic solution and recorded using the whole-cell patch-clamp technique. The PKC agonist phorbol dibutyrate (PDBu) enhanced ICl.swell in a concentration-dependent manner, which was reversed in isotonic solution and by a chloride current inhibitor, 9-anthracenecarboxylicacid. Furthermore, the PKC inhibitor bis-indolylmaleimide attenuated the effect and 4α-PDBu, an inactive PDBu analog, had no effect on ICl.swell. These results, obtained using the whole-cell patch-clamp technique, demonstrate the ability of PKC to activate ICl,swell in human atrial myocytes. This observation was consistent with a previous study using a single-channel patch-clamp technique, but differed from some findings in other species.
Anthracenes ; pharmacology ; Chloride Channels ; metabolism ; Chlorides ; agonists ; antagonists & inhibitors ; metabolism ; Culture Media ; metabolism ; pharmacology ; Dose-Response Relationship, Drug ; Evoked Potentials ; drug effects ; physiology ; Heart Atria ; cytology ; drug effects ; metabolism ; Humans ; Hypotonic Solutions ; metabolism ; pharmacology ; Indoles ; pharmacology ; Ion Transport ; drug effects ; Maleimides ; pharmacology ; Myocytes, Cardiac ; cytology ; drug effects ; metabolism ; Patch-Clamp Techniques ; Phorbol 12,13-Dibutyrate ; pharmacology ; Primary Cell Culture ; Protein Kinase C ; metabolism

OBJECTIVETo investigate the effect of the non-PLC-dependent protein kinase C (PKC) pathway of parathyroid hormone (PTH) on the apoptosis and proliferation of osteoblast MC-3T3E1 cells.

METHODSMC-3T3E1 cells were seeded in 96-well plates at the density of 1.5×10(4) cells/mL and incubated for 3 day. The cells were then exposed to 100 nmol/L of [Gly(1), Arg(19)]hPTH(1-28), 100 nmol/L of [Gly(1), Arg(19)]hPTH(1-34), 100 nmol/L of [Gly(1), Arg(19)]hPTH(1-34)+1 µmol/L Go6983, 1 µmol/L Go6983, or deionized water (control) for 1, 24 or 48 h. After the treatments, cell counting kit-8 (CCK-8) and Caspase-Glo® 3/7 Assay (Caspase-3) were used to examine the proliferation and apoptosis of MC3T3-E1 cells.

RESULTSCCK-8 results showed that hPTH(1-34) increased the number of MC3T3-E1 cells compared with hPTH(1-34)+Go6983 at 1 h and 24 h, but this difference was not statistically different. At 48 h, treatment with hPTH(1-34), as compared with hPTH(1-28), significantly increased the number of MC3T3-E1 cells (P<0.05), and this effect was blocked by the PKC inhibitor Go6983 (P<0.05). hPTH(1-34) did not result in significant inhibition of MC3T3-E1 cell apoptosis at 1 h and 24 h as compared with hPTH(1-34)+Go6983, but significantly inhibited the cell apoptosis as compared with hPTH(1-28) (P<0.05); this inhibitory effect was blocked by Go6983 (P<0.05).

CONCLUSIONs A relatively long time (for 48 h) of exposure to PTH can inhibit apoptosis and promote the proliferation of MC3T3-E1cells through a non-PLC-dependent PKC pathway.

3T3 Cells ; Animals ; Apoptosis ; Cell Proliferation ; Indoles ; pharmacology ; Maleimides ; pharmacology ; Mice ; Osteoblasts ; Parathyroid Hormone ; pharmacology ; Protein Kinase C ; antagonists & inhibitors ; metabolism ; Signal Transduction

Breast Neoplasms ; metabolism ; pathology ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; Down-Regulation ; drug effects ; Female ; Guanine Nucleotide Exchange Factors ; antagonists & inhibitors ; genetics ; metabolism ; Humans ; Indoles ; pharmacology ; MCF-7 Cells ; Maleimides ; pharmacology ; Protein Isoforms ; genetics ; metabolism ; Protein Kinase C ; antagonists & inhibitors ; genetics ; metabolism ; RNA Interference ; RNA, Small Interfering ; metabolism ; Receptor, ErbB-2 ; genetics ; metabolism ; Tetradecanoylphorbol Acetate ; toxicity

An F-box protein, beta-TrCP recognizes substrate proteins and destabilizes them through ubiquitin-dependent proteolysis. It regulates the stability of diverse proteins and functions as either a tumor suppressor or an oncogene. Although the regulation by beta-TrCP has been widely studied, the regulation of beta-TrCP itself is not well understood yet. In this study, we found that the level of beta-TrCP1 is downregulated by various protein kinase inhibitors in triple-negative breast cancer (TNBC) cells. A PI3K/mTOR inhibitor PI-103 reduced the level of beta-TrCP1 in a wide range of TNBC cells in a proteasome-dependent manner. Concomitantly, the levels of c-Myc and cyclin E were also downregulated by PI-103. PI-103 reduced the phosphorylation of beta-TrCP1 prior to its degradation. In addition, knockdown of beta-TrCP1 inhibited the proliferation of TNBC cells. We further identified that pharmacological inhibition of mTORC2 was sufficient to reduce the beta-TrCP1 and c-Myc levels. These results suggest that mTORC2 regulates the stability of beta-TrCP1 in TNBC cells and targeting beta-TrCP1 is a potential approach to treat human TNBC.
Cell Line, Tumor ; Cell Proliferation ; Cell Survival/drug effects ; Cyclin E/genetics/metabolism ; Dose-Response Relationship, Drug ; Female ; Furans/pharmacology ; Gene Knockdown Techniques ; Humans ; Models, Biological ; Multiprotein Complexes/antagonists & inhibitors ; Phosphatidylinositol 3-Kinases/*antagonists & inhibitors ; Phosphorylation/drug effects ; Protein Kinase Inhibitors/*pharmacology ; Proteolysis/drug effects ; Proto-Oncogene Proteins c-myc/genetics/metabolism ; Pyridines/pharmacology ; Pyrimidines/pharmacology ; TOR Serine-Threonine Kinases/*antagonists & inhibitors ; Triple Negative Breast Neoplasms/genetics/*metabolism ; beta-Transducin Repeat-Containing Proteins/genetics/*metabolism

The expression of hypoxia-inducible factor (HIF) is influenced by reactive oxygen species (ROS). Effect of bilirubin on HIF-1 expression in proximal tubular cells was investigated under physiological oxygen concentration, which is relative hypoxic condition mimicking oxygen content in the medulla of renal tissue. The human kidney (HK2) cells were cultured in 5% oxygen with or without bilirubin. HIF-1alpha protein expression was increased by bilirubin treatment at 0.01-0.2 mg/dL concentration. The messenger RNA expression of HIF-1alpha was increased by 1.69+/-0.05 folds in the cells cultured with 0.1 mg/dL bilirubin, compared to the control cells. The inhibitors of PI3K/mTOR, PI3K/AKT, and ERK 1/2 pathways did not attenuate increased HIF-1alpha expression by bilirubin. HIF-1alpha expression decreased by 10 microM exogenous hydrogen peroxide (H2O2); scavenger of ROS with or without bilirubin in the HK2 cells increased HIF-1alpha concentration more than that in the cells without bilirubin. Exogenous H2O2 decreased the phosphorylation of P70S6 kinase, which was completely reversed by bilirubin treatment. Knockdown of NOX4 gene by small interfering RNA (siRNA) increased HIF-1alpha mRNA expression. In coonclusion, bilirubin enhances HIF-1alpha transcription as well as the up-regulation of HIF-1alpha protein translation through the attenuation of ROS and subunits of NADPH oxidase.
Bilirubin/*pharmacology ; Cell Line ; Epithelial Cells/cytology/metabolism ; Humans ; Hydrogen Peroxide/toxicity ; Hypoxia-Inducible Factor 1, alpha Subunit/genetics/*metabolism ; Kidney Tubules, Proximal/cytology ; Mitogen-Activated Protein Kinase 1/metabolism ; Mitogen-Activated Protein Kinase 3/metabolism ; NADPH Oxidase/antagonists & inhibitors/genetics/metabolism ; Oxygen/*pharmacology ; Phosphatidylinositol 3-Kinases/metabolism ; Phosphorylation/drug effects ; Proto-Oncogene Proteins c-akt/metabolism ; RNA Interference ; Ribosomal Protein S6 Kinases, 70-kDa/metabolism ; Signal Transduction/drug effects ; TOR Serine-Threonine Kinases/metabolism ; Transcriptional Activation/*drug effects ; Up-Regulation/drug effects

Small molecule covalent inhibitors, or called as irreversible inhibitors, are a type of inhibitors that exert their biological functions by irreversibly binding to target through covalent bonds. Compared with non-covalent inhibitors, covalent inhibitors have obvious advantages in bioactivity. Nevertheless, these agents may also exhibit larger toxicity once off-target effects arise. This "double-edged swords" property often leads drug researchers to avoid attaching them. In recent years, some problems such as drug resistance are difficult to be solved with reversible inhibitors leading researchers to pay more attention on the covalent inhibitors. In this review, we shall make a short summary to the recent research progress of covalent inhibitors and the interaction modes between covalent inhibitors and their target protein residues.
Amino Acids ; chemistry ; Antineoplastic Agents ; chemical synthesis ; chemistry ; therapeutic use ; Antiviral Agents ; chemical synthesis ; chemistry ; therapeutic use ; Drug Discovery ; Drug Resistance ; Enzyme Inhibitors ; chemical synthesis ; chemistry ; therapeutic use ; Hepatitis C ; drug therapy ; Humans ; Molecular Structure ; Neoplasms ; drug therapy ; Protein Binding ; Protein Kinase Inhibitors ; chemical synthesis ; chemistry ; therapeutic use ; Receptor, Epidermal Growth Factor ; antagonists & inhibitors ; Serine Proteinase Inhibitors ; chemical synthesis ; chemistry ; therapeutic use

To investigate the role of the extracellular signal-regulated kinase (ERK1/2) and PI3K/AKT/ mTOR signal pathway inducing bone marrow mesenchymal stem cells (BMSCs) differentiation into neural cells, mouse bone marrow-derived mesenchymal stem cell lines D1 cells were used as research object. And they were divided into control groups and salidroside (SD) groups. Different concentrations (5, 25, 50, 100 and 200 microg x mL(-1) of SD were used and SD (100 microg x mL(-1)) was used to induce at different time (0.5, 1, 3, 6, 9, 12, 24, 48 and 72 h). The immunofluorescence staining chemical technology, real-time PCR and Western blotting were used to detect the positive rates of NSE, MAP2, beta-Tubulin III, NES, GFAP and the expression levels of beta-Tubulin III, NSE, ERK1/2, AKT. The expression of ERK1/2 and NSE was detected when the ERK1/2 and PI3K/AKT/ mTOR signal pathway was blocked by PD98059 and LY294002. It indicated that the positive rates of NSE, MAP2, beta-Tubulin III, NES and GFAP were gradually enhanced with time increased. The expression level of NSE and beta-Tubulin III protein were significantly higher than those in control groups (P < 0.01). The expression of ERK1/2, AKT mRNA and protein were higher with concentration and time increased. When the ERK1/2 and PI3K/AKT/mTOR signal pathway were blocked, the expression levels of NSE, NES and beta-Tubulin III mRNA and NSE protein were inhibited significantly. It points out that SD can stimulate the ERK1/2 and PI3K/AKT/mTOR signal pathway to promote BMSCs differentiation into neural cells.
Animals ; Bone Marrow Cells ; cytology ; Cell Differentiation ; drug effects ; Cells, Cultured ; Chromones ; pharmacology ; Enzyme Inhibitors ; pharmacology ; Flavonoids ; pharmacology ; Glial Fibrillary Acidic Protein ; metabolism ; Glucosides ; antagonists & inhibitors ; isolation & purification ; pharmacology ; MAP Kinase Signaling System ; drug effects ; Mesenchymal Stromal Cells ; cytology ; Mice ; Microtubule-Associated Proteins ; metabolism ; Mitogen-Activated Protein Kinase 1 ; genetics ; metabolism ; Mitogen-Activated Protein Kinase 3 ; genetics ; metabolism ; Morpholines ; pharmacology ; Nestin ; metabolism ; Neurons ; cytology ; metabolism ; Phenols ; antagonists & inhibitors ; isolation & purification ; pharmacology ; Phosphatidylinositol 3-Kinases ; metabolism ; Phosphopyruvate Hydratase ; genetics ; metabolism ; Plants, Medicinal ; chemistry ; Protein Kinase Inhibitors ; pharmacology ; Proto-Oncogene Proteins c-akt ; genetics ; metabolism ; RNA, Messenger ; metabolism ; Rhodiola ; chemistry ; Signal Transduction ; drug effects ; TOR Serine-Threonine Kinases ; metabolism ; Tubulin ; metabolism