Protein kinase C beta II upregulates intercellular adhesion molecule-1 via mitochondrial activation in cultured endothelial cells

Activation of protein kinase C (PKC) is closely linked with endothelial dysfunction. However, the effect of PKCβII on endothelial dysfunction has not been characterized in cultured endothelial cells. Here, using adenoviral PKCβII gene transfer and pharmacological inhibitors, the role of PKCβII on endothelial dysfucntion was investigated in cultured endothelial cells. Phorbol 12-myristate 13-acetate (PMA) increased reactive oxygen species (ROS), p66shc phosphorylation, intracellular adhesion molecule-1, and monocyte adhesion, which were inhibited by PKCβi (10 nM), a selective inhibitor of PKCβII. PMA increased the phosphorylation of CREB and manganese superoxide dismutase (MnSOD), which were also inhibited by PKCβi. Gene silencing of CREB inhibited PMA-induced MnSOD expression, suggesting that CREB plays a key role in MnSOD expression. Gene silencing of PKCβII inhibited PMA-induced mitochondrial ROS, MnSOD, and ICAM-1 expression. In contrast, overexpression of PKCβII using adenoviral PKCβII increased mitochondrial ROS, MnSOD, ICAM-1, and p66shc phosphorylation in cultured endothelial cells. Finally, PKCβII-induced ICAM-1 expression was inhibited by Mito-TEMPO, a mitochondrial ROS scavenger, suggesting the involvement of mitochondrial ROS in PKC-induced vascular inflammation. Taken together, the results suggest that PKCβII plays an important role in PMA-induced endothelial dysfunction, and that the inhibition of PKCβII-dependent p66shc signaling acts as a therapeutic target for vascular inflammatory diseases.

Roles of PKCβ/P66Shc oxidative stress signal pathway in mediating hyperoxia-induced ROS production in alveolar epithelial cells / 中国当代儿科杂志

<p><b>OBJECTIVE</b>To explore the roles of PKCβ/P66Shc oxidative stress signal pathway in mediating hyperoxia-induced reactive oxgen species (ROS) production in alveolar epithelial cells (A549) and the protective effects of PKCβ inhibitor on hyperoxia-induced injuries of alveolar epithelial cells.</p><p><b>METHODS</b>A549 cells were cultured in vitro and randomly divided into three groups: control, hyperoxia and PKCβ inhibitor LY333531 treatment. The hyperoxia group was exposed to a mixture of O2 (950 mL/L) and CO2 (50 mL/L) for 10 minutes and then cultured in a closed environment. The LY333531 group was treated with PKCβ inhibitor LY333531 of 10 µmol/L for 24 hours before hyperoxia induction. Cells were collected 24 hours after culture and the levels of PKCβ, Pin1, P66Shc and P66Shc-Ser36 were detected by Western blot. The intracellular translocation of P66Shc, the production of ROS and cellular mitochondria membrane potential were measured using the confocal microscopy.</p><p><b>RESULTS</b>Compared with the control group, the levels of PKCβ, Pin1, P66Shc and P-P66Shc-Ser36 in A549 cells 24 hours after culture increased significantly in the hyperoxia group. These changes in the hyperoxia group were accompanied with an increased translocation rate of P66Shc from cytoplasm into mitochondria, an increased production of mitochondrial ROS, and a reduced mitochondrial membrane potential. Compared with the hyperoxia group, the levels of Pin1, P66Shc and P66Shc-Ser36 in A549 cells, the translocation rate of P66Shc from cytoplasm into mitochondria and the production of mitochondrial ROS decreased significantly, while the mitochondrial membrane potential increased significantly in the LY333531 treatment group. However, there were significant differences in the above mentioned measurements between the LY333531 treatment and control groups.</p><p><b>CONCLUSIONS</b>Hyperoxia can increase the expression of PKCβ in alveolar epithelial cells and production of mitochondrial ROS and decrease mitochondrial membrane potential. PKCβ inhibitor LY333531 can partially disrupt these changes and thus alleviate the hyperoxia-induced alveolar epithelial cell injury.</p>

Caracterização da proteína quinase C Beta I nuclear em células tronco embrionárias / Characterization of protein kinase C beta I in embryonic stem cell nucleus

As proteína quinases C (PKC) pertencem à família das serina/treonina quinases, que vem sendo apontadas como importantes enzimas para os processos de proliferação e diferenciação das células tronco embrionárias (CTE), todavia, a função exata de cada isoforma dessa família ainda não está clara. Dados anteriores do nosso laboratório indicam que dentre as PKCs expressas em CTE, formas cataliticamente ativas da PKCßI são altamente expressas no núcleo das CTE murinas. Estas ao se diferenciarem expressam essa quinase no seu citoplasma ou deixam de expressar a mesma, e que a maioria dos alvos da PKCßI em CTE indiferenciada estão envolvidos em processos de regulação da transcrição de proteínas envolvidas em processos de proliferação/ diferenciação. Dando continuidade aos resultados anteriores do laboratório, no presente trabalho, com técnicas de proteômica e fosfoproteômica identificamos outros alvos nucleares da PKCßI em CTE indiferenciadas. Vimos que de fato inibindo-se a PKCßI diminuiu-se a fostorilação de fatores envolvidos com a indiferenciação das CTE. Dentre os alvos da PKCßI encontramos a proteína adaptadora, TIF1 que recruta proteínas remodeladoras de cromatina. Essa proteína é essencial para a manutenção do estado indiferenciado das CTE. In vitro a PKCßI foi capaz de fosforilar a TIF1ß e inibindo-se a PKCßI por RNAi vimos uma diminuição na expressão da TIF1ß e no fator de indiferenciação Nanog cuja expressão já foi demonstrada ser regulada pela TIF1ß. Além disso vimos que inibindo-se a PKCßI com o peptídeo inibidor da PKCßI aumentou a expressão de proteínas reguladas pelo c-Myc. E que o RNAi para a PKCßI aumentou a expressão de proteínas que regulam a expressão do c-Myc. Não vimos nenhum efeito na fosforilação ou expressão do c-Myc após a inibição da PKCßI o que sugere que a PKCßI ative proteínas repressoras do c-Myc. Nossos estudos sugerem que a PKCßI regula a manutenção do estado indiferenciado das CTE regulando a expressão e atividade da Tif1ß um possível alvo direto da PKCßI. Levando a modificações da cromatina e regulação da expressão de genes que mantém as CTE indiferenciadas. Outro ponto de regulação da PKCßI parece ser a nibição da atividade de c-Myc o que seria importante para a manutenção do estado indiferenciado visto que o c-Myc é um amplificador das vias de sinalização que mantém as células proliferando. Desta forma a PKCßI parece ter um papel central na regulação da expressão gênica de CTE à nível de modificações epigenéticas e a nível transcricional mantendo as CTE indiferenciadas

The Protein kinase C (PKC) family of serine/treonine kinases, are being described as important enzymes for proliferation and diferentiation of embryonic stem cells (ESC), however, the exact function of the different isoenzymes of this family still is unclear. Previous data from our laboratory indicates that amongst the PKCs expressed in ESC, catalytically active forms of PKCßI are highly expressed in nucleus of murine ESC. When these cells differentiate this kinase can be found in the cytoplasm or not expressed at all, and that the majority of PKCßI targets in undifferentiated ESC are involved in the regulation of proteins involved in transcription of proteins involved in proliferation/ diferentiation. Continuing our previous work herewith using proteomics and phosphoproteomics techniques we identified other nuclear PKCßI targets in undifferentiated ESC. We indeed saw that inhibiting PKCßI decreased the phosphorylation of factors involved with maintainance of the undifferentiated state of ESC. Amongst the targets of PKCßI we found the adaptor protein, TIF1ßI, that recruits cromatin remodeling proteins. This protein is essential for the maintenance of the undifferentiated state of ESC. In vitro PKCßI phosphorylated TIF1ß and inhibiting PKCßI with RNAi decreased the expression of TIF1ß and of the undifferentiation factor Nanog whose expression has been shown to be regulated by TIF1ß. We also saw that inhibiting PKCßI with a peptide inhibitor increased the expression of proteins regulated by c-Myc, and that RNAi for PKCßI increased the expression of proteins that regulate the expression of c-Myc. We did not see any effect on the phosphorylation or expression of c-Myc after inhibition of PKCßI suggesting that PKCßI activates c-Myc repressor proteins. Our studies sugest that PKCßI regulates the maintenance of the undiferentiated state of ESC regulating the expression and activity of Tif1ß a possibly a direct target of PKCßI, leading to chromatin modifications and regulation of genes that maintain ESC undiferentiated. Another form of regulation of PKCßI seems to be by inhibiting the activity of c-Myc which is importante to maintain ESC undifferentiated since c-Myc is na an amplifyer of signaling patheways that maintain ESC proliferating. Together PKCßI has a central role in the regulation of the gene expression of ESC at the level of epigenetic modifications and transcriptional regulation

Identificação e validação funcional de novos alvos das PKCs em célula tronco embrionária / Identification and functional validation of new targets of PKC in embryonic stem cell

Algumas das estratégias utilizadas para entender a biologia de células tronco embrionária (CTE) são baseadas na identificação de cascatas de sinalização que induzem a diferenciação e auto-renovação das CTE através da interferência seletiva de processos específicos. A família das proteínas quinase C (PKC) é conhecida por participar dos processos de auto-renovação e diferenciação celular em CTE, entretanto, o papel específico das diferentes isoenzimas das PKCs ainda precisa ser elucidado. Desta forma investigamos. o papel das PKCs atípicas (aPKCs) em CTE indiferenciadas utilizando um inibidor específico para estas serina/ treonina quinases, o peptídeo pseudossubstrato das aPKCs, e fosfoproteômica. A maioria das proteinas identificadas cuja fosforilação reduziu após o tratamento com o inibidor das aPKC, são proteínas envolvidas com o metabolismo principalmente com a via glicolítica. Além disso, a inibição das aPKCs levou a redução do consumo de glicose, secreção de lactato, acompanhada da redução da atividade da lactato desidrogenase, e aumento da fosforilação oxidativa, sendo analisada através do consumo de oxigênio após o tratamento com oligomicina e FCCP. Verificamos também que as aPKCs são capazes de fosforilar diretamente a piruvato quinase. A glicólise aeróbica parece ser fundamental para a manutenção da indiferenciação das CTE, e demonstramos que as aPKCs participam deste processo auxiliando na auto-renovação das CTE indiferenciadas. Também observamos que as aPKCs assim como a PKCßI modulam a fosforilação da α-tubulina, porém ao passo que as aPKCs interagem com a α-tubulina durante a interfase, a PKCßI interage com a mesma apenas durate a mitose. Estes resultados motivaram a segunda parte da tese, na qual o papel da fosforilação da α-tubulina pela PKCßI foi investigado. O resíduo de treonina 253, conservado em diversas espécies de vertebrados e localizado na interface de polimerização entre a α- e a ß-tubulina foi identificado, como um novo sítio de fosforilação da α-tubulina pela PKCßI. Este sítio não está em um consenso linear para a PKC, entretanto é um consenso formado estruturalmente, onde aminoácidos básicos distantes na sequência linear se tornam justapostos na estrutura terciária da proteína. Estudos de simulação por dinâmica molecular demonstraram que a interação entre a α e ß-tubulina aumenta após esta fosforilação, uma vez que T253 fosforilada passa a interagir com K105, um residuo conservado na ß-tubulina. A fosforilação in vitro de α-tubulina aumenta a taxa de polimerização da tubulina e a inibição da PKCßI em células reduziu a taxa de repolimerização do microtubulo após o tratamento com nocodazol. Além disso, a importância da fosforilação deste sítio foi demonstrada pelo fato de que um mutante fosfomimético GFP-α-tubulina, T253E ser mais incorporado no fuso mitótico ao passo que T253A foi menos incorporado do que a proteína selvagem. Nossos dados suportam a hipótese que os consensos estruturais formados podem ser importantes sítios de reconhecimento pelas quinases e que a fosforilação de T253 da α-tubulina afeta a estabilidade do polímero. Em conclusão, utilizando métodos de fosfoproteômica e interferência seletiva de vias de sinalização, combinados a validações experimentais dos alvos identificados podemos propor a importância funcional das aPKCs e PKCßI em CTE indiferenciadas

Some of the strategies used to understand stem cell biology are based on the identification of signalling cascades that lead to differentiation and self-renewal of embryonic stem cells (ESC) by selective interference of specific signalling processes. The protein kinase C (PKC) family is known to participate in ESC self-renewal and differentiation, however, the specific role of the different PKC isoenzymes in these cells remains to be determined. Therefore, we investigated the role of atypical PKCs (aPKC) in undifferntiated ESC using a specific inhibitor for these serine/ threonine kinases, pseudo-substrate peptide of aPKCs, and phosphoproteomics. The majority of proteins whose phosphorylation decreased upon aPKC inhibition, are proteins involved in metabolism in particular with the glycolytic pathway. Besides that, inhibiton of aPKCs led to a decrease in glucose uptake and lactate secretion, followed by a decrease in lactate dehydrogenase activity, and an increase in mitochondrial activity as measured by oxygen consumption after treatment with olygomycin and a chemical uncoupler. We also verified that aPKCs are able to directly phosphorylated pyruvate kinase. Aerobic glicolysis seems to be fundamental for the maintainance of undifferentiated ESC, and we demonstrated that aPKCs participte in these processes helping to maintain self-renewal of undifferentiated ESC. We also observed that aPKCs as PKCßI modulate the phosphorylation of α-tubulin, however, while aPKCs interact with α-tubulin during interfase PKCßI interacts with α-tubulin only during mitosis. These results lead to the second part of this thesis. We investigated the role of α-tubulina phosphorylation by PKCßI. Indentifying threonine 253, a conserved residue in several vertebrate species, of localized at the polymerization interface between α- and ß-tubulin, as a phosphorylation site of α-tubulin by PKCßI. This site is not in a linear consensus for PKC, however, it is in a structuraly formed consensus, where basic aminoacids distant in the linear sequence are juxtaposed in the three dimentional protein structure. Simulation studies by molecular dynamics show that the interaction between α and ß-tubulin increases upon this phosphorylation, once, phosphorylated T253 interacts with com K105, a conserved residue in ß-tubulin. The in vitro phosphorylation of α-tubulin increased tubulin polymerization rate and inhibiton of PKCßI in cells reduced repolimeration rate of microtubles upon treatment with nocodazole. Besides that, the importance of this phosphorylation site were demonstrated by the fact that a phosphomimetic mutant GFP-α-tubulina, T253E is more incorporated in mitotic fuses while T253A is less than wild type. Our data support the hypothesis that structural consensus may be important sites recognized and that T253 phosphorylation of α-tubulin afects the polymer stability. In conclusion, using phosphoproteomics methods and selective interference of signal transduction pathways combined with experimental validation studies of the identified targets we can propose roles for aPKCs and PKCßI in undifferentiated ESC

Association between mannose-binding lectin 2 gene and protein kinase C-beta 1 gene polymorphisms and type 2 diabetic macrovascular complications in northern Chinese Han population / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To assess the association between single nucleotide polymorphisms (SNPs) of mannose-binding lectin 2 gene (MBL2) (rs1800450, rs1800451 and rs11003125) and protein kinase C-beta 1 gene (PRKC beta 1) (rs3700106, rs2575390) with diabetic macroangiopathy in northern Chinese Han population.</p><p><b>METHODS</b>The samples have included 318 type 2 diabetes mellitus (T2DM) patients and 448 normoglycemic controls. The five SNPs were determined by a Multiplex SnaPshot method. Biochemical indices such as fasting plasma-glucose, triglyceride and total cholesterol were also measured. Linkage disequilibrium and haplotype analysis were carried out for all samples using Haploview 4.2. Additive model was applied to assess the effect of interaction between SNPs and environment factors on macrovascular complications.</p><p><b>RESULTS</b>Genotypic frequencies of rs11003125 have differed significantly between the controls and patients with coronary heart disease and peripheral vascular disease (P=0.024 and 0.004, respectively). The allele frequency of rs11003125 was also statistically significant between the two groups (P=0.014 and 0.001, respectively). Compared with patients without macrovascular complications, the allele frequency of rs11003125 was significantly different in patients with peripheral vascular disease (P=0.031). No significant differences were found between the distribution of the genotype frequency and allele frequencies of other variants. Haplotype analysis indicated that, compared with controls and patients without macrovascular complications, individuals with G allele of rs1800450 and C allele of rs11003125 had a higher risk for macrovascular complications.</p><p><b>CONCLUSION</b>The rs11003125 polymorphism located in the promoter region of MBL2 gene is associated with macrovascular complications of T2DM in northern Chinese Han population. G allele of rs1800450 and C allele of rs11003125 may be risk factors for macrovascular complications. There were additive interactive effects for rs11003125 polymorphism (GC+CC) and hypertension, diabetic nephropathy, diabetic neuropathy and diabetic retinopathy on macrovascular complications.</p>

The effect of chelerythrine on the hypertrophy of cardiac myocytes of neonatal rats induced by different glucose levels and its mechanism / 药学学报

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.

Update on treatments of diabetic macular edema / 中华医学杂志(英文版)

<p><b>OBJECTIVE</b>To review the update research progress about the treatment of diabetic macular edema and to give helpful guidelines in the treatment of diabetic macular edema based on available evidence to date.Data sources A literature search of all English articles was performed on the online electronic PubMed database dated 1984 to 2009. The keywords searched included: macular edema, therapy, laser coagulation, intravitreal triamcinolone acetonide, vascular endothelial growth factor inhibitor, protein kinase C inhibitor and Pars plana vitrectomy. After finding relevant articles within these search limits, a manual search was conducted through the references from these articles.Study selection Original articles and critical reviews were reviewed and selected to address the stated purpose.</p><p><b>RESULTS</b>To date, demonstrated means to reduce the risk of vision loss from diabetic macular edema include focal/grid laser photocoagulation and improved metabolic control. Emerging pharmacologic therapies (intravitreal triamcinolone acetonide, vascular endothelial growth factor inhibitors and protein kinase C beta-isoform inhibitors) and Pars plana vitrectomy have shown early promise in the treatment of diabetic macular edema.</p><p><b>CONCLUSIONS</b>As there has been extensive development in multiple treatments of diabetic macular edema, choice of the most suitable treatment for specific patients becomes important. Combination therapy of laser, pharmacological and surgical treatment modalities may offer an alternative to treatment of diabetic macular edema.</p>

Role of PKCbeta in the malignant tumors and enzastaurin, a PKCbeta inhibitor / 药学学报

Protein kinase C beta (PKCbeta) is a multifunctional serine/threonine protein kinase, which plays an important role in many cell signaling pathways. PKCbeta takes part in multiple physiological processes, including regulation of the cell cycle, differentiation, proliferation, apoptosis and angiogenesis. Increased PKCbeta activity has been observed in many human cancers, such as colon, breast and haematological malignancies. At present, Enzastaurin is mostly studied in preclinical and clinical studies, which is a selective PKCbeta inhibitor. This review focuses on the functional properties of PKCbeta, its role played in tumors and Enzastaurin.

Association between cardiac troponin I phosphorylation/degradation and cardiomyopathies / 中华心血管病杂志

<p><b>OBJECTIVE</b>To investigate the association between cTnI phosphorylation/degradation and cardiomyopathies in extransplanted myocardium.</p><p><b>METHODS</b>cTnI phosphorylation and degradation as well as PKC (beta1, beta2) expressions were determined in extransplanted hearts from patients with cardiomyopathies (n = 8) and from traffic accidents (n = 6) by Western blot.</p><p><b>RESULTS</b>The cTnI bands were observed in LV myocardium of cardiomyopathy patients and normal myocardium while and cTnI degradation bands were only detected in LV myocardium from patients with cardiomyopathies. The phosphorylated cTnI bands were significantly upregulated in LV myocardium of cardiomyopathy patients compared to normal myocardium (P < 0.05). There was no myocardial PKCbeta1, PKCbeta2 expression in all examined hearts.</p><p><b>CONCLUSION</b>The cTnI degradation products and increased phosphorylated cTnI expression are likely involved in the pathogenesis and development of cardiomyopathy.</p>

Immunolocalization of Protein Kinase C Isoenzymes alpha, betaI, betaII and gamma in Adult and Developing Rat Kidney

Protein kinase C (PKC) plays an important role not only in signal transduction mechanisms in various biological processes, but also in the regulation of growth and differentiation during development. We studied the classical PKC alpha, betaI, betaII and gamma, with regard to their expression in adult and developing rat kidney. PKCalpha appeared in the ureteric bud at embryonic day (E) 16, and the proximal and distal anlage at E18. After birth, the immunoreactivity of PKCalpha gradually decreased. In adult, PKCalpha was expressed intensely in the connecting tubule (CNT), the collecting ducts (CD) and the renal corpuscle, and weakly in the proximal and distal tubules. PKCbetaI appeared in the ureteric bud at E16, and the proximal anlage at E18. After birth, the immunoreactivity of PKCbetaI gradually disappeared from the CD and proximal tubule. In adult, PKCbetaI was expressed in the intercalated cells of the CNT and cortical CD, the proximal straight tubule, and the renal corpuscle. PKCbII appeared in distal anlage at E18, and increased markedly after birth. In the CD, PKCbetaII immunoreactivity appeared after birth. In adult, PKCbetaII was expressed in the distal tubule, the CNT and the CD. The immunoreactivity for PKCgamma appeared only in the proximal anlage at E18, and increased temporally around the time of birth. However, no immunoreactivity for PKCgamma was observed in adult rat kidney. These results indicate that classical PKC isoforms appear to play a role in the regulation of various renal functions and differentiation within specific functional units of the uriniferous tubule in rat kidney.

nm23-H1 gene inhibits lung cancer cell invasion through down-regulation of PKC signal pathway / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To study the molecular mechanisms of nm23-H1 for regulating PKC signal pathway before and after transfection with nm23-H1 gene.</p><p><b>METHODS</b>Using 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.</p><p><b>RESULTS</b>(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).</p><p><b>CONCLUSION</b>The 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.</p>