Protective effect of protein kinase C inhibitor on rat renal vascular endothelial injury induced by lipopolysaccharide / 中华危重病急救医学

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. Conclusion PKC inhibitor could significantly attenuate the damage of vascular endothelial barrier induced by LPS, and plays an important role in endothelial cell barrier.

Effect of Protein Kinase C Inhibitor Enzastaurin on Growth of Gefitinib-resistant Human Non-small Cell Lung Cancer Cell Lines / 中国药师

Objective: To observe the effect of a novel targeted agent enzastaurin alone or in combination with gefitinib on ge-fitinib-resistant human non-small cell lung cancer cells to explore the rational drug combination. Methods: CCK-8 assay was used to measure the cell proliferation. Combination index ( CI) was calculated by Chou-Talalay method to assess the efficacy of the combination therapy. The flow cytometry (FCM) was used to analyze the change in the cell cycle. Results:In 72h, the IC50 value of gefitinib and enzastaurin for the lung cancer NCI-H460 cells was 6. 99μmol·L-1 (95%CI:3. 55-13. 79μmol·L-1 ) and 7. 25μmol·L-1 (95%CI:4. 77-1. 02 μmol·L-1), respectively. The inhibition effect on the cell proliferation was stronger in the combination treatment than that in the monotherapy (P<0. 05), and the simultaneous treatment showed the most significant inhibition effect (P<0. 01). The IC50 value of gefitinib for H460 cells in the simultaneous administration group, the sequential administration group with gefitinib used first and the sequential administration group with enzastaurin used first was 0.006 μmol·L-1(95%CI:0.002-0.020μmol·L-1), 0.02μmol·L-1(95%CI:0.011-0.037 μmol·L-1) and 0.085 μmol·L-1(95% CI:0.042-0.170μmol·L-1, respectively. The CI of the simultaneous administration group was lower than one when the gefitinib concentration was above 0. 05μmol·L-1 . The cell cycle distribution result indicated that the simultaneous administration group had significantly increased G0/G1 proportion (P<0. 05) and induced cell cycle arrest at G1 phase. Conclusion:Protein kinase C inhibitor enzastaurin combined with EGFR inhibitor gefitinib shows a synergistic effect, suggesting that the combination treatment of the two drugs might be a new strategy for the follow-up therapy of gefitinib-resistant non-small cell lung cancer.

Effects of Staurosporine on the Proliferation and Apoptosis of Human Cholangiocarcinoma QBC-939 Cells / 医药导报

Objective To study the effects of protein kinase C (PKC) inhibitor staurosporine (STS) on the proliferation and apoptosis of human cholangiocarcinoma QBC-939 cells and to explore its possible mechanism. Methods CCK-8 was used to detect the effects of PKC inhibitor STS on the proliferation of human cholangiocarcinoma QBC-939 cells. The effects of STS on the ultrastructural characteristics of QBC-939 cells were observed by routine transmission electron microscopy (TEM). The apoptosis rate and the cell cycle distribution of QBC-939 cells were detected by flow cytometry. The expression of cyclin B1,Cdk1 and p-Cdk1 in QBC-939 cells was detected by Western blotting. Results STS could significantly inhibit the proliferation of QBC-939 cells in a dose-dependent manner (P <0. 05) and the half inhibitory concentration ( IC50 ) of QBC-939 cells at 24th and 48th h was 334 nmol·L-1 and 118 nmol · L-1 , respectively. TEM observed that STS could induce typical apoptotic bodies and super-microstructural changes of QBC-939 cells. By Annexin V-FITC/ PI double labeling flow cytometry,we found that the apoptotic rate of QBC-939 cells after treatment with STS for 0,12,24 and 48 h was (10. 16±4. 52)% ,(22. 35±2. 19)% ,(34. 27±2. 30)% and (59. 70±5. 97)% ,respectively. By flow cytometry,compared with the control group,STS could significantly increase apoptosis rate of QBC-939 cells,decrease the percentage of cells in G0 / G1 phase and increase the percentage of cells in G2 / M phase (P<0. 05). Western blotting proved that the expression levels of cyclin B1 and Cdk1 proteins in the STS-treated QBC-939 cells were significantly decreased (P<0. 05),while the expression level of p-Cdk1 protein in the STS-treated QBC-939 cells was significantly increased ( P < 0. 05 ). Conclusion STS can significantly inhibit cell proliferation and induce apoptosis of human cholangiocarcinoma QBC-939 cells and the mechanism may be related to cell cycle arrest at G2 / M phase.

Ruboxistaurin for the Treatment of Diabetic Peripheral Neuropathy: A Systematic Review of Randomized Clinical Trials

BACKGROUND: Diabetic peripheral neuropathy (DPN) is a common complication of diabetes mellitus. Protein kinase C (PKC) inhibitor's has been thought to be a potential disease modifying drug's in DPN as it slows or reverse neuropathy's progression. To assesses the efficacy and safety of ruboxistaurin on the progression of symptoms, signs, or functional disability in DPN. METHODS: A systematic review of the literature databases like PubMed, ProQuest, EBSCO, EMBASE, and Cochrane Central was performed up to August 2012. We included randomized controlled trials (RCTs) comparing PKC inhibitor ruboxistaurin (RBX) with control and lasting at least 6 months. Our primary outcome measure was change in neurological examination, measured by neurological total symptom score (NTSS) and vibration detection threshold (VDT). Secondary outcome measures were total quality of life (QoL), skin microvascular blood flow and others. RESULTS: Six RCTs were included in review. Change in neurological function assessed by NTSS was reported in six studies, out of which significant difference between the RBX and placebo group seen in four studies favouring treatment group while remaining two studies reported no significant difference. VDT was assessed in only one study in which no significant difference seen between RBX and placebo group. Two studies reported significant improvement in QoL data. Safety data was reported in only two studies in which none of side effect was related to RBX. CONCLUSION: RBX had effects on DPN in some studies, but the evidence is not enough for meta-analysis and firm conclusion.

Ruboxistaurin for the Treatment of Diabetic Peripheral Neuropathy: A Systematic Review of Randomized Clinical Trials

BACKGROUND: Diabetic peripheral neuropathy (DPN) is a common complication of diabetes mellitus. Protein kinase C (PKC) inhibitor's has been thought to be a potential disease modifying drug's in DPN as it slows or reverse neuropathy's progression. To assesses the efficacy and safety of ruboxistaurin on the progression of symptoms, signs, or functional disability in DPN. METHODS: A systematic review of the literature databases like PubMed, ProQuest, EBSCO, EMBASE, and Cochrane Central was performed up to August 2012. We included randomized controlled trials (RCTs) comparing PKC inhibitor ruboxistaurin (RBX) with control and lasting at least 6 months. Our primary outcome measure was change in neurological examination, measured by neurological total symptom score (NTSS) and vibration detection threshold (VDT). Secondary outcome measures were total quality of life (QoL), skin microvascular blood flow and others. RESULTS: Six RCTs were included in review. Change in neurological function assessed by NTSS was reported in six studies, out of which significant difference between the RBX and placebo group seen in four studies favouring treatment group while remaining two studies reported no significant difference. VDT was assessed in only one study in which no significant difference seen between RBX and placebo group. Two studies reported significant improvement in QoL data. Safety data was reported in only two studies in which none of side effect was related to RBX. CONCLUSION: RBX had effects on DPN in some studies, but the evidence is not enough for meta-analysis and firm conclusion.

Regulation of src-suppressed C kinase substrate on the expression of TNF-α in endothelial cells / 中华急诊医学杂志

Objective To study the role of src-suppressed C kinase substrate (SSeCKS) in the secretion of tumor necrosis factor (TNF-α) in rat pulmonary micro-vascular endothelial cells (PMVEC) induced by lipopolysaccharide (LPS).Methods Wistar rat PMVEC cultured in vitro were randomly (random number) divided into several groups (n =4) as per exposure to given dosage of LPS for different lengths of time and to different dosages of LPS for given length of time.After PMVEC exposed to 10 mg/L LPS for 1 hour (h),3 h,6 h,12 h and 24 h or 0.1 mg/L,1 mg/L and 10 mg/L LPS for 24 h,the levels of TNF-αin the supernatant of culture medium were examined by the method of enzyme linked immunosorbent assay (ELISA).Another PMVEC was pre-treated by protein kinase C (PKC) inhibitor bis-indolylmaleimide (BIM) for 0.5 h or had the transfection of SSeCKS-specific small interfering RNA (siRNA) for 48 h before 10 mg/L LPS challenge for 24 h,and subsequently the supernatant was also examined by ELISA.One-way analysis of variance (ANOVA) was employed for statistical analysis by SPSS version 10.0 to compare values among all groups.A significant difference was presumed as a probability value ＜ 0.05.Results After PMVEC incubated with 0.1 mg/L,1 mg/L and 10 mg/L LPS for 24 hours,the levels of TNF-αsecreted were (253.70 ± 23.55),(327.88 ± 37.25),(403.20 ± 36.22),respectively,which were higher than that in un-stimulated PMVEC (82.28 ± 22.56,all P =0.000).After 10 mg/L LPS challenge for one hour,the level of TNF-αin the supernatant of PMVEC raised substantially (170.11 ±49.22),peaked at the time of 6 h (404.82 ± 13.78),then persisted at a higher level until 24 h (395.67 ± 36.23) than that in un-stimulated PMVEC (84.60 ± 23.61,P =0.001,0.000,0.000,respectively).After PMVEC pre-incubated with BIM,the level of LPS-induced TNF-αdecreased obviously (200.44 ± 27.39 vs.402.28 ± 31.07,P =0.000).Compared with LPS challenged PMVEC (407.28 ± 32.64),depletion of endogenous SSeCKS in PMVEC after inhibited by SSeCKS-siRNA significantly attenuated increase in the level of LPS-induced TNF-α (195.20 ± 13.28,P =0.000).Conclusions Down-activation of SSeCKS and PKC can inhibit the secretion of TNF-αin PMVEC induced by LPS,relieving the inflammatory response of PMVEC.

Antagonists of NMDA Receptor, Calcium Channel and Protein Kinase C Potentiate Inhibitory Action of Morphine on Responses of Rat Dorsal Horn Neuron

he present study was designed to examine whether the co-application of morphine with Ca2+ channel antagonist (Mn2+, verapamil), N-methyl-D-aspartate (NMDA) receptor antagonist (2-amino-5-phosphonopentanoic acid[AP5], Mg2+) or protein kinase C inhibitor (H-7) causes the potentiation of morphine- induced antinociceptive action by using an in vivo electrophysiological technique. A single iontophoretic application of morphine or an antagonist alone induced weak inhibition of wide dynamic range (WDR) cell responses to iontophoretically applied NMDA and C-fiber stimulation. Although there was a little difference in the potentiating effects, the antinociceptive action of morphine was potentiated when morphine was iontophoretically applied together with Mn2+, verapamil, AP5, Mg2+ or H-7. However, the potentiating action between morphine and each antagonist was not apparent, when the antinociceptive action evoked by morphine or the antagonist alone was too strong. These results suggest that the potentiating effect can be caused by the interaction between morphine and each antagonist in the spinal dorsal horn.

Effect of Protein Kinase C Inhibitor (Staurosporine) in Human Invasive Bladder Tumor Cells / 대한비뇨기과학회지

Protein Kinase C which is a Ca++ -activated, phospholipid - dependent enzyme phosphorylates numerous protein substrates and participates in intracellular signaling processes. Protein kinase C is associated with a wide range of biological effects including stimulus-secretion coupling, induction of cellular proliferation and differentiation, activation of nuclear transcription factors and cell surface receptors and tumor promotion. Programmed cell death, referred to apoptosis is an active, energy-dependent process in which the cell participates in its own destruction during apoptosis. There is condensation and fragmentation of nuclear chromatin, accompanied by a marked decline in total cell volume, dilation of the endoplasmic reticulum and general compacting of cellular organelles. Thereafter, there is fragmentation of both nucleus and cytoplasm to give rise to small membrane-bound vesicles known as apoptotic bodies. Protein kinase C may have the regulatory role in apoptosis. Staurosporine is a potent protein kinase C inhibitor. Staurosporine inhibited the growth of human invasive bladder tumor cells, T24 in MTT test. The survival fractions of human invasive bladder tumor cells T24 were 100.0%, 76.0%, 62.5% and 18.1% with staurosporine concentration 0nM, 10nM, 100nM and 1000nM, respectively. From the results we identified that staurosporine inhibited the growth of T24 cells markedly in a dose dependent manner(P<0.05). 12-hour exposure of T24 cells to staurosporine failed to induce DNA fragmentation at the concentrations of 0nM, 10nM and 100nM but promoted fragmentation at the concentration of 1000nM, showing typical ladder pattern on agarose gel electrophoresis. On the examination of cellular morphology, T24 cells showed the features of apoptosis such as cell shrinkage, nuclear condensation and formation of bleb and apoptotic bodies after exposure to staurosporine of 10nM, 100nM and 1000nM concentrations. These results suggest that staurosporine have remarkable cytotoxic effect against human invasive bladder tumor cells T 24 and the mechanism of cytotoxicity may be apoptosis.

Protein kinase C is involved in the induction and early- phase maintenance of long-term potentiation of C-fiber evoked field potentials in spinal dorsal horn of adult rats / 中国病理生理杂志

AIM: The role of protein kinase C (PKC) in th e induction and maintenance of spinal long-term potentiation (LTP) was evaluated . METHODS: The C-fiber evoked field potentials were recorded at t he superficial layers of spinal dorsal horn at the lumbar enlargement. RESULTS: (i) Chelerythrine (200 ?mol/L) or G 6983 (100 ? mol/L), a selective PKC inhibitor, completely blocked LTP induction. (ii) Chel eryt hrine or G 6983 reversed spinal LTP in a time-dependent manner. 15 min after L TP induction, chelerythrine (200 ?mol/L) and G 6983 (100 ?mol/L) depre ssed LTP to baseline in all tested rats. The same concentration of chelerythrine and G 6983, applied at 3 h after LTP induction, did not affect LTP. CONCLUSION: PKC in spinal dorsal horn may be crucial for the ind uction and the early-phase maintenance of LTP of C-fiber evoked field potentials .