The purpose of this study is to investigate the effect of chelerythrine on the hypertrophy of cardiomyocytes of neonatal rats induced by different glucose levels and its mechanism. Using cultured neonatal ventricular myocytes as a model, groups were divided as: control (5 mmol x L(-1)); high glucose level (10, 15, 20, and 25.5 mmol x L(-1)); high glucose level (25.5 mmol x L(-1)) add different concentrations of chelerythrine (1 and 8 micromol x L(-1)); and control glucose level (5 mmol x L(-1)) add different concentrations of chelerythrine (1 and 8 micromol x L(-1)). Different groups of cardiomyocytes after adding corresponding treat factors were cultured for 48 hours. Cardiomyocytes' diameters and protein level were measured and the expression of PKC-alpha, PKC-beta2, p-PKC-alpha, and p-PKC-beta2 were measured by Western blotting. Compared with control group, neonatal myocytes cultured in high glucose levels showed increased cellular volumes, protein level and expression of PKC-alpha, PKC-beta2, p-PKC-alpha, p-PKC-beta2. When chelerythrine was added, cellular volumes, protein level and expression of PKC-alpha, PKC-beta2, p-PKC-alpha, p-PKC-beta2 were significantly reduced. But in 1 micromol x L(-1) chelerythrine group, the expression of PKC-beta2 was not significantly reduced. The result suggested that chelerythrine can reverse the hypertrophy induced by different glucose levels on the cardiac myocytes, it may have protective effect against diabetic cardiomyopathy via PKC passageway.
Animals ; Animals, Newborn ; Benzophenanthridines ; pharmacology ; Cells, Cultured ; Diabetes Mellitus, Experimental ; drug therapy ; metabolism ; Dose-Response Relationship, Drug ; Glucose ; administration & dosage ; Hypertrophy ; chemically induced ; pathology ; Hypoglycemic Agents ; pharmacology ; Myocytes, Cardiac ; drug effects ; pathology ; Phosphorylation ; Protein Kinase C ; antagonists & inhibitors ; metabolism ; Protein Kinase C beta ; Protein Kinase C-alpha ; metabolism ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo study the molecular mechanisms of nm23-H1 for regulating PKC signal pathway before and after transfection with nm23-H1 gene.

METHODSUsing Western-blot, Boyden-chamber, MTT and laser scanning confocal microscopy (LSCM) techniques to detect the distribution of PKC in cytosol and plasma membrane, changes of invasion and proliferation activity, PKC translocation status and changes of intracellular Ca(2+) concentration among different human pulmonary carcinoma cells with transfected or untransfected nm23-H1 gene, and changes of the three cell lines after treatment with Calphostin C, a PKC inhibitor.

RESULTS(1) The expression of PKCalpha, PKCbeta II on L9981 and L9981-pLXSN cell membrane, which was in activated status, was remarkably higher than those in L9981-nm23-H1 cell line (P < 0.001). The expression of PKCalpha, PKCbeta II in cytosol in L9981 and L9981-pLXSN cell lines, which was in inactivated status, was lower than those in L9981-nm23-H1 cell line (P < 0.001). It means that the PKC signal pathway was activated in L9981 and L9981-pLXSN cell lines. (2) PKCalpha and PKCbeta II mainly located in nuclei and perinuclear area in L9981 and L9981-pLXSN cells, which were in active status, and the Ca(2+) concentration in these cells was obviously higher than that in L9981-nm23-H1 cell line (P < 0.01). In L9981-nm23-H1 cell line, which was transfected with nm23-H1 gene, PKCalpha and PKCbeta II mainly located in soluble cytosolic section, in an inactive status. (3) The invasion and proliferation ability of L9981 and L9981-pLXSN lung cancer cells was higher than that of L9981-nm23-H1 cell line (P < 0.001). There was no statistically significant difference between L9981 and L9981-pLXSN cell lines (P > 0.05). (4) After treated with PKC inhibitor Calphstin C, the expression of PKC and PKCbeta II in membrane in L9981 and L9981-pLXSN cell lines was down-regulated (P < 0.001), PKCalpha and PKCbeta II were mainly located in cytosolic area, mainly in an inactive status, and the Ca(2+) concentration was found to be decreased in all the three cell lines. The invasion and proliferation ability of the three lung cancer cell lines were obviously decreasing (P < 0.001). However, the invasion and proliferation ability of L9981-nm23-H1 lung cancer cell line was still lower than that of L9981 and L9981-pLXSN lung cancer cell lines (P < 0.001). There was also no significant difference between L9981 and L9981-pLXSN cell lines (P > 0.05).

CONCLUSIONThe results of this study suggest that nm23-H1 gene might inhibit the invasion and metastasis of lung cancer cells by down-regulating PKC signaling pathway. The Ca(2+) in cells might be involved in this process.

Calcium ; metabolism ; Cell Line, Tumor ; Cell Membrane ; metabolism ; Cell Proliferation ; drug effects ; Cytosol ; metabolism ; Down-Regulation ; Humans ; Lung Neoplasms ; enzymology ; metabolism ; pathology ; NM23 Nucleoside Diphosphate Kinases ; genetics ; Naphthalenes ; pharmacology ; Neoplasm Invasiveness ; Protein Kinase C ; antagonists & inhibitors ; metabolism ; Protein Kinase C beta ; Protein Kinase C-alpha ; metabolism ; Signal Transduction ; Transfection

AIMTo determine how SDF-1 alpha/CXCR4 activates nuclear factor-kappa B (NF-kappaB) and promotes oral squamous cell carcinoma (OSCC) invasion.

METHODOLOGYA lentivirus-based knockdown approach was utilized to deplete gene expression. NF-kappaB activation was evaluated by Western blot analysis and electrophoretic mobility shift (EMSA).

RESULTSWe show that the activation of NF-kappaB by CXCR4 occurs through the Carma3/Bcl10/Malt1 (CBM) complex in OSCC. We found that loss of components of the CBM complex in HNSCC can inhibit SDF-1 alpha induced phosphorylation and degradation of IkappaBalpha, while TNF alpha induced IKK activation remains unchanged. Further, we identified a role for novel and atypical, but not classical, PKCs in activating IKK through CXCR4. Importantly, inhibition of the CBM complex leads to a significant decrease in SDF-1 alpha mediated invasion of OSCC.

CONCLUSIONThe CBM complex plays a critical role in CXCR4-induced NF-kappaB activation in OSCC. Targeting molecular components of the NF-kappaB signaling pathway may provide an important therapeutic opportunity in controlling the progression and metastasis of OSCC mediated by SDF-1 alpha.

Adaptor Proteins, Signal Transducing ; antagonists & inhibitors ; physiology ; B-Cell CLL-Lymphoma 10 Protein ; CARD Signaling Adaptor Proteins ; antagonists & inhibitors ; physiology ; Carcinoma, Squamous Cell ; pathology ; Caspase Inhibitors ; Caspases ; physiology ; Cell Line, Tumor ; Chemokine CXCL12 ; antagonists & inhibitors ; physiology ; Enzyme Activation ; drug effects ; Gene Silencing ; Genetic Vectors ; genetics ; Humans ; I-kappa B Kinase ; drug effects ; I-kappa B Proteins ; metabolism ; Isoenzymes ; antagonists & inhibitors ; Lentivirus ; genetics ; Membrane Proteins ; antagonists & inhibitors ; physiology ; Mouth Neoplasms ; pathology ; Mucosa-Associated Lymphoid Tissue Lymphoma Translocation 1 Protein ; NF-KappaB Inhibitor alpha ; NF-kappa B ; antagonists & inhibitors ; physiology ; Neoplasm Invasiveness ; Neoplasm Proteins ; antagonists & inhibitors ; physiology ; Phosphorylation ; Plasmids ; genetics ; Protein Kinase C ; antagonists & inhibitors ; Receptors, CXCR4 ; physiology ; Tumor Necrosis Factor-alpha ; pharmacology

BACKGROUNDIncreased proliferation of pulmonary vascular cells and muscularisation of pulmonary vessels are frequently observed in human smokers and in animals exposed to cigarette smoke. To elucidate the molecular mechanisms leading to these changes, we studied the in vitro effect of cigarette smoke extract (CSE) on proliferation of pulmonary artery smooth muscle cells (PASMCs) and activation of protein kinase C (PKC), an important kinase implicated in cell proliferation.

METHODSPASMCs cultured from 12 normal Wistar rats were studied in the following conditions: (1) PASMCs were exposed to different concentrations of CSE for 24 hours, then MTT colorimetric assay was used for detection of cell proliferation. Cell viability was assessed by trypan blue exclusion. (2) PASMCs were pre-incubated with phorbol 12-myristate 13-acetate (PMA) for 24 hours or Ro31-8220 for 30 minutes before exposure to 5% CSE for 24 hours. Cell proliferation was examined by MTT colorimetric assay, cell cycle analysis and proliferating cell nuclear antigen (PCNA) immunocytochemical staining. (3) PASMCs were exposed to 5% CSE for 24 hours. Then PKC-alpha mRNA expression was detected by reverse transcription-polymerase chain reaction (RT-PCR) and protein expression by Western blotting, while PKC-alpha translocation was observed by immunofluorescence staining and confocal microscopy. (4) PASMCs were transfected with specific antisense oligodeoxynucleotides against PKC-alpha 6 hours before exposure to 5% CSE for 24 hours. PKC-alpha protein expression and cell proliferation were detected by methods described previously.

RESULTS(1) Low concentration of CSE (5%) increased proliferation of PASMCs, whereas high concentrations (20%, 30%) were inhibitory as a result of cytotoxicity. (2) The value of absorbance (Value A), proliferation index (PI), S-phase cell fraction (SPF) and average optical density of PCNA staining in PASMCs from 5% CSE exposure group (0.306 +/- 0.033, 0.339 +/- 0.033, 0.175 +/- 0.021, 0.315 +/- 0.038, respectively) were significantly increased compared with those of control group (0.249 +/- 0.018, 0.177 +/- 0.055, 0.092 +/- 0.023, 0.187 +/- 0.022, respectively) (P < 0.05). PKC down-regulation by PMA pretreatment or PKC inhibition by Ro31-8220 pre-incubation abolished the effect of 5% CSE on PASMCs proliferation. (3) After exposure to 5% CSE for 24 hours, PKC-alpha mRNA and protein expression in PASMCs (1.054 +/- 0.078, 1.185 +/- 0.041, respectively) were much higher than in untreated cells (0.573 +/- 0.054, 0.671 +/- 0.055, respectively) (P < 0.01). Moreover, 5% CSE induced a translocation of PKC-alpha from cytoplasm toward the perinuclear area and into the nucleus. (4) Specific antisense oligodeoxynucleotides against PKC-alpha reduced 5% CSE-induced expression of PKC-alpha protein (0.713 +/- 0.047 vs 1.180 +/- 0.056), also abolished the effect of 5% CSE on PASMCs proliferation significantly.

CONCLUSIONSCSE can be cytotoxic at high concentrations. But at low concentrations, it makes a mitogenic effect on cultured PASMCs. PKC, especially its alpha isozyme, seems to play an important role in CSE-induced proliferation of PASMC.

Animals ; Cell Proliferation ; Cells, Cultured ; Indoles ; pharmacology ; Male ; Muscle, Smooth, Vascular ; cytology ; Myocytes, Smooth Muscle ; cytology ; Oligodeoxyribonucleotides, Antisense ; pharmacology ; Protein Kinase C-alpha ; antagonists & inhibitors ; physiology ; Pulmonary Artery ; cytology ; Rats ; Rats, Wistar ; Smoke ; Tobacco

OBJECTIVETo explore the mechanism of reversal of multidrug resistance in renal carcinoma cells by protein kinase C inhibitor.

METHODSRT-PCR, Western blot and inverted fluorescent microscopy were used to determine the expression of PKCalpha and MDR related gene MDR1, MRP1, LRP in RCC cells transferred by PKCalpha cDNA. Also effects of activator and inhibitor of PKC in combination with adriamycin on multidrug resistance in RCC cells were evaluated by MTT.

RESULTSThe results of semi-quantitative RT-PCR analysis showed that the expression level of MDR1 was higher in RCC cells transferred by PKCalpha cDNA than in RCC cells, the reversal effectiveness of PKC inhibitors in combination with adriamycin (ADM) was apparently favorable. IC(50) of ADM in 786 - 0 cells was 7.8015e(-7) (5.7046e(-7) to 1.0669e(-6)); IC(50) of ADM in PKCalpha/786 - 0 cells was 1.6588e(-6) (1.1621e(-6) to 2.3677e(-6)); IC(50) of ADM in combination with PMA in PKCalpha/786 - 0 cells was 2.6794e(-6) (2.0521e(-6) to 3.4983e(-6)); IC(50) of ADM in combination with calphostin C in PKCalpha/786 - 0 cells was 9.2506e(-8) (5.9337e(-8) to 1.4422e(-7)).

CONCLUSIONPKC inhibitors can reverse multidrug resistance in renal carcinoma cells in vitro via changes of expression of MDR1.

ATP-Binding Cassette, Sub-Family B, Member 1 ; metabolism ; Antibiotics, Antineoplastic ; pharmacology ; Cell Line, Tumor ; DNA, Complementary ; genetics ; Doxorubicin ; pharmacology ; Drug Resistance, Multiple ; Drug Resistance, Neoplasm ; Genetic Vectors ; Humans ; Inhibitory Concentration 50 ; Kidney Neoplasms ; metabolism ; pathology ; Multidrug Resistance-Associated Proteins ; metabolism ; Naphthalenes ; pharmacology ; Protein Kinase C ; antagonists & inhibitors ; Protein Kinase C-alpha ; genetics ; metabolism ; Tetradecanoylphorbol Acetate ; pharmacology ; Transfection

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

Cholangiocarcinoma (CC) is a chemoresistant intrahepatic bile duct carcinoma with a poor prognosis. The aims of this study were to identify molecular pathways that enhance sesquiterpene lactone parthenolide (PTL)-induced anticancer effects on CC cells. The effects of PTL on apoptosis and hemoxygenase-1 (HO-1) induction were examined in CC cell lines. The enhancement of PTL-mediated apoptosis by modulation of HO-1 expression and the mechanisms involved were also examined in an in vitro cell system. Low PTL concentrations (5 to 10 micrometer) led to Nrf2-dependent HO-1 induction, which attenuated the apoptogenic effect of PTL in Choi-CK and SCK cells. PTL-mediated apoptosis was enhanced by the protein kinase C-alpha inhibitor Ro317549 (Ro) through inhibition of expression and nuclear translocation of Nrf2, resulting in blockage of HO-1 expression. Finally, HO-1 silencing resulted in enhancement of apoptotic cell death in CC cells. The combination of PTL and Ro efficiently improved tumor growth inhibition compared to treatment with either agent alone in an in vivo subcutaneous tumor model. In conclusion, the modulation of HO-1 expression substantially improved the anticancer effect of PTL. The combination of PTL and Ro could prove to be a valuable chemotherapeutic strategy for CC.
Active Transport, Cell Nucleus/drug effects ; Antineoplastic Agents/chemistry/*pharmacology ; Apoptosis/drug effects/genetics ; Cell Line, Tumor ; Cell Nucleus/*metabolism ; Cholangiocarcinoma/drug therapy/*metabolism/pathology ; Drug Resistance, Neoplasm/drug effects/genetics ; Enzyme Activation ; Enzyme Inhibitors/pharmacology ; Heme Oxygenase-1/genetics/*metabolism ; Humans ; Lactones/chemistry ; NF-E2-Related Factor 2/genetics/*metabolism ; Protein Kinase C-alpha/antagonists & inhibitors ; RNA, Small Interfering/genetics ; Sesquiterpenes/chemistry/*pharmacology ; Signal Transduction/drug effects