Involvement of fatty acid-CoA ligase 4 in hepatocellular carcinoma growth： Roles of cyclic AMP and p38 mitogen-activated protein kinase

AIM: Fatty acid-CoA ligase 4 (FACL4) is an arachidonate-preferring enzyme which has been shown to be up-regulated in human colon cancer tissues and implicated in the colon tumorigenesis. The purpose of this study was to investigate the role of FACL4 in the human hepatocellular carcinoma (HCC) tumorigenesis and the specific signal pathways involved in this process. METHODS: We investigated the expression and regulation of FACL4 in HCC, adjacent non-tumorous liver tissues, and cell lines. RESULTS: In HCC patients, we demonstrated that FACL4 gene expression was markedly elevated in the cancerous tissues than in the adjacent non-cancerous liver tissues. In addition, several human hepatoma cell lines, including Hep3B and HepG2, expressed high levels of FACL4. Stable overex-pression of FACL4 knockdown plasmids (small interfering RNA, siRNA) to Hep3B cells significantly decreased FACL4 expression and subsequently limited the cell proliferation. Treatment of Hep3B cells with 8-bromo-cAMP and SB203508 (p38 MAPK inhibitor) significantly suppressed the FACL4 expression. CONCLUSION: FACL4 is involved in the HCC tumorigenesis and both cAMP and p38 MAPK pathways are associated with the regulation of FACL4 in HCC.     

Nuclear factor kappa B： A marker of chemotherapy for human stage Ⅳ gastric carcinoma

AIM： To detect the nuclear factor kappa B （NF-κB） condition in human stage IV gastric carcinoma patients and to explore the correlation between NF-κB activation and survival of these patients after chemotherapy. METHODS： Expression of NF-κB-p65 was determined by immunohistochemical analysis. Activity of NF-κB DNA-binding in carcinoma tissue was detected by electrophoretic mobility shift assay. Kaplan-Meier survival analysis was performed to show the relation between NF-κB and progression-free survival （PFS） or overall survival （OS） of the patients. RESULTS： The positive expression rate of NF-κB-p65 in 60 gastric cancer tissue samples was 76.7% （46160）. The expression of NF-κB-p65 was reduced in adjacent carcinoma and normal tissue samples. Electrophoretic mobility shift assay （EMSA） analysis showed a strong activation of NF-κB in cancer tissue samples. A survival difference was found in NF-κB-p65 positive and negative patients. NF-κB-p65 expression was negative in cancer tissue samples （n = 14）. PFS was 191.40 ± 59.88 d and 152.93 ±16.99 d, respectively, in patients with positive NF-κB-p65 expression （n = 46） （P = 0.4028）. The survival time of patients with negative and positive NF-κB-p65 expression was 425.16 ±61.61 d and 418.85 ±42.98 d, respectively （P = 0.7303）. Kaplan-Meier analysis showed no significant difference in PFS or OS. The 46 patient tissue which positive NF-κB-p65 expression was found in the tissue samples from the 46 patients whose PFS and OS were 564.89 ± 75.94 d and s 352.37 ±41.32 d, respectively （P = 0.0165）. CONCLUSION： NF-κB is activated in gastric carcinoma tissue, which is related to the OS after chemotherapy.     

Expression and significance of nuclear factor κB p65 in colon tissues of rats with TNBS-induced colitis

AIM: To investigate the role of NF-κB in the pathogenesis of TNBS-induced colitis in rats. METHODS: Thirty-two healthy adult Sprague-Dawley (SD) rats were randomly divided into four groups of eight each: normal, NS, model Ⅰ, model Ⅱ groups in our study. Rat colitis model was established through 2-,4-,6-trinitrobenzene sulfonic acid (TNBS) enema. At the end of four weeks, the macroscopical and histological changes of the colon were examined and mucosa myeloperoxidase (MPO)activities assayed. NF-~B p65 expression was determined by Western blot assessment in cytoplasmic and nuclear extracts of colon tissue, and the expressions of TNF-α (and ICAM-1 protein in colon tissue were examined by immunohistochemistry. The relativities between expression of NF-κB p65 and other parameters were analyzed. RESULTS: TNBS enema resulted in pronounced pathological changes of colonic mucosa in model Ⅱ group (macroscopic and histological injury indices 6.25±1.39 and 6.24±1.04, respectively), which were in accordance with the significantly elevated MPO activity (1.69+0.11). And the nuclear level of NF-κB and expression of TNF-α, ICAM-1 in rats of model Ⅱ group were higher than that of normal control(9.7±1.96 vs 1.7±0.15, 84.09±14.52 vs 16.03±6.21,77.69±8.09 vs 13.41±4.91 P<0.01), Linear correlation analysis revealed that there were strong correlations between the nuclear level of NF-κB and the tissue positive expression of TNF-α and ICAM-1, MPO activities, macroscopical and histological indices in TNBS-induced colitis, respectively (r = 0.8235, 0.8780, 0.8572, 0.9152,0.8247; P<0.05). CONCLUSION: NF-κB plays a pivotal role in the pathogenesis of ulcerative colitis, which might account for the up-regulation the expression of TNF-α and ICAM-1.     

Role of atypical protein kinase C in activation of sterol regulatory element binding protein-1c and nuclear factor kappa B (NFκB) in liver of rodents used as a model of diabetes, and relationships to hyperlipidaemia and insulin resistance

Aims/hypothesis  Previous findings in rodents used as a model of diabetes suggest that insulin activation of atypical protein kinase C (aPKC) is impaired in muscle, but, unexpectedly, conserved in liver, despite impaired hepatic protein kinase B (PKB/Akt) activation. Moreover, aPKC at least partly regulates two major transactivators: (1) hepatic sterol receptor binding protein-1c (SREBP-1c), which controls lipid synthesis; and (2) nuclear factor kappa B (NFκB), which promotes inflammation and systemic insulin resistance. Methods  In Goto–Kakizaki rats used as a model of type 2 diabetes, we examined: (1) whether differences in hepatic aPKC and PKB activation reflect differences in activation of IRS-1- and IRS-2-dependent phosphatidylinositol 3-kinase (PI3K); (2) whether hepatic SREBP-1c and NFκB are excessively activated by aPKC; and (3) metabolic consequences of excessive activation of hepatic aPKC, SREBP-1c and NFκB. Results  In liver, as well as in muscle, IRS-2/PI3K activation by insulin was intact, whereas IRS-1/PI3K activation by insulin was impaired. Moreover, hepatic IRS-2 is known to control hepatic aPKC during insulin activation. Against this background, selective inhibition of hepatic aPKC by adenoviral-mediated expression of mRNA encoding kinase-inactive aPKC or short hairpin RNA targeting Irs2 mRNA and partially depleting hepatic IRS-2 diminished hepatic SREBP-1c production and NFκB activities, concomitantly improving serum lipids and insulin signalling in muscle and liver. Similar improvements in SREBP-1c, NFκB and insulin signalling were seen in ob/ob mice following inhibition of hepatic aPKC. Conclusions/interpretation  In diabetic rodent liver, diminished PKB activation may largely reflect impaired IRS-1/PI3K activation, while conserved aPKC activation reflects retained IRS-2/PI3K activity. Hepatic aPKC may also contribute importantly to excessive SREPB-1c and NFκB activities. Excessive hepatic aPKC-dependent activation of SREBP-1c and NFκB may contribute importantly to hyperlipidaemia and systemic insulin resistance. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorised users.     

Involvement of p38 mitogen-activated protein kinase in acquired gemcitabine-resistant human urothelial carcinoma sublines

Resistance to chemotherapeutic drugs is one of the major challenges in the treatment of cancer. A better understanding of how resistance arises and what molecular alterations correlate with resistance is the key to developing novel effective therapeutic strategies. To investigate the underlying mechanisms of gemcitabine (Gem) resistance and provide possible therapeutic options, three Gem-resistant urothelial carcinoma sublines were established (NG0.6, NG0.8, and NG1.0). These cells were cross-resistant to arabinofuranosyl cytidine and cisplatin, but sensitive to 5-fluorouracil. The resistant cells expressed lower values of [hENT1 × dCK/RRM1 × RRM2] mRNA ratio. Two adenosine triphosphate-binding cassette proteins ABCD1 as well as multidrug resistance protein 1 were elevated. Moreover, cyclin D1, cyclin-dependent kinases 2 and 4 were upregulated, whereas extracellular signal-regulated kinase 1/2 and p38 mitogen-activated protein kinase (MAPK) activity were repressed significantly. Administration of p38 MAPK inhibitor significantly reduced the Gem sensitivity in NTUB1 cells, whereas that of an extracellular signal-regulated kinase MAPK inhibitor did not. Furthermore, the Gem-resistant sublines also exhibited higher migration ability. Forced expression of p38 MAPK impaired the cell migration activity and augmented Gem sensitivity in NG1.0 cells. Taken together, these results demonstrate that complex mechanisms were merged in acquiring Gem resistance and provide information that can be important for developing therapeutic targets for treating Gem-resistant tumors.     

Inhibition of p38 mitogen-activated protein kinase may decrease intestinal epithelial cell apoptosis and improve intestinal epithelial barrier function after ischemia- reperfusion injury

AIM: To investigate the role of p38 mitogen-activated protein kinase in rat small intestine after ischemia-reperfusion (I/R) insult and the relationship between activation of p38 MAPK and apoptotic cell death of intestine. METHODS: Ninety Wistar rats were divided randomly into three groups, namely sham-operated group (C), I/R vehicle group (R) and SB203580 pre-treated group (S). In groups R and S, the superior mesenteric artery (SMA) was separated and occluded for 45 min, then released for reperfusion for 0.25, 0.5, 1, 2, 6, 12 and 24 h. In group C, SMA was separated without occlusion. Plasma D-lactate levels were examined and histological changes were observed under a light microscope. The activity of p38 MAPK was determined by Western immunoblotting and apoptotic cells were detected by the terminal deoxynucleotidyl transferase (TdT)-mediated dUDP-biotin nick end labeling (TUNEL). RESULTS: Intestinal ischemia followed by reperfusion activated p38 MAPK, and the maximal level of activation (7.3-fold vs sham-operated group) was reached 30 min after I/R. Treatment with SB 203580, a p38 MAPK inhibitor, reduced intestinal apoptosis (26.72±3.39% vs62.50±3.08% in I/R vehicle, P<0.01) and decreased plasma D-lactate level (0.78±0.15 mmol/L in I/R vehicle vs0.42±0.17 mmol/L in SB-treated group) and improved post-ischemic intestinal histological damage. CONCLUSION: p38 MAPK plays a crucial role in the signal transduction pathway mediating post-ischemic intestinal apoptosis, and inhibition of p38 MAPK may attenuate ischemia-reperfusion injury.     

在Fas诱导Bel-7402细胞凋亡中p38MAPK调节Bcl-2的表达

目的:探讨p38MPAK是否参与Fas和AD诱导Bel-7402细胞的凋亡过程,以及p38MPAK和bcl-2的关系,进一步揭示p38MAPK的凋亡途径.方法:在Fas和AD作用24h后,用MTT法检测Bel-7402细胞的活力,用Western-blot和RT- PCR法检测p38MAPK,p-p38MAPK和Bcl-2 expression,用免疫荧光法对p-p38MAPK进行细胞定位.结果:随着Fas浓度的增加,Bel-7402细胞的活力明显抑制,p38MAPK和p-p38MAPK表达明显增高(P<0.01),且p-p38MAPK由胞质易位到胞核.Bcl-2的表达明显降低(P<0.01),并且这种降低趋势被p38MAPK抑制剂SB203580所阻止.结论:p38MAPK参与Fas诱导的凋亡途径,以磷酸化形式激活后抑制Bcl一2的表达,进而促进细胞凋亡.     

The p38 mitogen-activated protein kinase pathway--a potential target for intervention in infarction, hypertrophy, and heart failure

The p38 mitogen-activated protein kinases (p38s) are stress-activated Ser/Thr kinases. Their activation has been associated with various pathological stressors in the heart. Activated p38 is implicated in a wide spectrum of cardiac pathologies, including hypertrophy, myocardial infarction, as well as systolic and diastolic heart failure. In this review, the specific contribution of different isoforms of p38 kinases to cardiac diseases as well as TAB-1-mediated non-canonical activation pathway are discussed as a rationale for inhibiting p38 activity to treat cardiac hypertrophy, ischemic injury, and heart failure. Finally, a summary of current clinical trials targeting p38 kinases in cardiovascular diseases is provided to highlight the potential promise as well as existing challenges of this therapeutic approach. This article is part of a special issue entitled “Key Signaling Molecules in Hypertrophy and Heart Failure.”     

p38丝裂原活化蛋白激酶抑制剂减少大鼠肝脏炎症细胞因子的表达

目的 观察p38丝裂原活化蛋白激酶(MAPK)抑制剂SB203580阻断p36 MAPK信号通路,减少脑死亡大鼠肝脏促炎细胞因子表达的作用.方法 雄性Wistar大鼠30只,体质量180～200 g,随机分3组,每组10只.脑死亡组:诱导大鼠及死亡;脑死亡+SB203580组:大鼠脑死亡诱导成功后,经阴茎背静脉注射SB203580(10 mg/kg);两组大鼠脑死亡诱导成功,行人工呼吸6 h后,若平均动脉压大于80 mm Hg(1 mm Hg=0.133 kPa),则为脑死亡供体,获取肝脏待检.对照组:正常大鼠麻醉后取肝脏待检.逆转录-聚合酶链反应检测肝脏肿瘤坏死因子(TNF)α和白细胞介素(IL)-1β的mRNA表达,Western blot检测肝脏TNF α和IL-1 β的蛋白质表达以及磷酸化p38 MAPK的表达.多个样本间比较行One-Way ANOVA分析,SNK法行两两样本间比较.结果 脑死亡组大鼠肝脏出现p38 MAPK磷酸化,磷酸化p38 MAPK的相对表达量比对照组明显增加(0.190±0.004比0.001±0.002),差异有统计学意义(q=172.53,P＜0.01);肝脏TNF α的mRNA和蛋白质表达量分别为0.670±0.012和0.240±0.003,较对照组(分别为0.130±0.013和0.001±0.002)明显增加(q值分别为123.99和243.09,P值均＜0.01);肝脏IL-1 β的mRNA和蛋白质表达量分别为0.560±0.009和0.190±0.003,较对照组(分别为0.160±0.010和0.001±0.002)明显增加(q值分别为135.35和192.23,P值均＜0.01).脑死亡SB203580组大鼠肝脏p38 MAPK磷酸化下降,磷酸化p38 MAPK的表达量(0.120±0.004)比脑死亡组明显下降(q=63.90,P＜0.05),但仍明显高于对照组(q=108.63,P＜0.01);肝脏TNF α的mRNA和蛋白质表达量分别为0.430±0.016和0.180±0.004,较脑死亡组明显下降(q值分别为55.11和61.03,P值均＜0.01),但仍高于对照组(q值分别为68.89和182.06,P值均＜0.01);肝脏IL-1β的mRNA和蛋白质表达量分别为0.270±0.009和0.140±0.004,较脑死亡组明显下降(q值分别为98.13和50.85,P值均＜0.01),但仍高于对照组(q值分别为37.22和141.38,P值均＜0.01).结论 SB203580能抑制p38 MAPK的磷酸化,阻断p38 MAPK信号通路,减少脑死亡大鼠肝脏促炎细胞因子表达,降低肝脏免疫原性.     

川芎嗪对哮喘小鼠p38蛋白激酶及类胰蛋白酶表达的影响

目的探讨川芎嗪对哮喘小鼠p38蛋白激酶（p38MAPK）及类胰蛋白酶表达的影响。方法将30只BALB/c小鼠随机分为3组：A组（对照组）、B组（哮喘组）及C组（川芎嗪组）,每组10只,采用鸡卵清蛋白（OVA）与免疫佐剂（氢氧化铝）腹腔注射致敏及用1%OVA生理盐水溶液雾化激发的方法制备哮喘小鼠模型,C组小鼠于每次激发前1 h腹腔注射川芎嗪（80mg/kg/d）,每天1次,持续5 d,A组腹腔注射等量生理盐水致敏及雾化吸入。行HE染色镜下观察各组肺组织病理改变,并采用免疫组织化学染色SP法半定量测定行肺组织中p38MAPK及类胰蛋白酶表达情况。结果 C组小鼠肺组织HE染色病理改变较B组有减轻,且免疫组化结果显示测定C组小鼠肺组织较B组p38MAPK及类胰蛋白酶MOD有降低（P〈0.05）。结论川芎嗪减轻哮喘气道炎症,部分机制可能是通过影响p38蛋白激酶信号通路及肥大细胞活化实现。     

The activation of p38alpha, and not p38beta, mitogen-activated protein kinase is required for ischemic preconditioning

Numerous studies show that pharmacological inhibition of p38 mitogen-activated protein kinases (p38s) before lethal ischemia prevents conditioning. However, these inhibitors have off-target effects and do not discriminate between the alpha and beta isoforms; the activation of which is thought to have diverse and perhaps opposing actions with p38α aggravating, and p38β reducing, myocardial injury. We adopted a chemical genetic approach using mice in which either the p38α (DRα) or p38β (DRβ) alleles were targeted to substitute the “gatekeeper” threonine residue for methionine, thereby preventing the binding of a pharmacological inhibitor, SB203580. Isolated, perfused wild-type (WT), DRα and DRβ mouse hearts underwent ischemic preconditioning with 4 cycles of 4 min ischemia/6 min reperfusion, with or without SB203580 (10 µM), followed by 30 min of global ischemia and 120 min of reperfusion. In WT and DRβ hearts, SB203580 completely abolished the reduction in myocardial infarction seen with preconditioning and also the phosphorylation of downstream substrates of p38. These effects of SB203580 were not seen in DRα hearts. Furthermore ischemic preconditioning occurred unaltered in p38β null hearts. Contrary to expectation the activation of p38α, and not p38β, is necessary for ischemic preconditioning. Since p38α is also the isoform that leads to lethal myocardial injury, it is unlikely that targeted therapeutic strategies to achieve isoform-selective inhibition will only prevent the harmful consequences of activation.     

p38MAPK对大鼠肾小球系膜细胞表达COX-2的影响

目的 探讨p38丝裂原活化蛋白激酶（p38MAPK）和环氧化酶2（COX-2）的关系,从而研究p38MAPK和COX-2在糖尿病肾病（DN）中的作用机制.方法 分别以高葡萄糖、高胰岛素、过氧化氢和糖基化终产物孵育大鼠肾小球系膜细胞系HBZY-1;先以p38MAPK特异抑制剂SB203580预处理细胞系HBZY-1,再给予上述4种因素孵育细胞系HBZY-1,观察细胞系HBZY-1 p38MAPK和COX-2的表达.结果 高葡萄糖、高胰岛素、过氧化氢和糖基化终产物均可独立激活p38MAPK,使其磷酸化表达量增加,COX-2表达也明显增加;SB203580预处理后,COX-2表达被显著抑制.结论 p38MAPK调控COX-2的表达,表明p38MAPK是COX-2的上游激酶之一,p38MAPK和COX-2可能在DN的发生发展过程中起重要作用.     

p38 mitogen‐activated protein kinase impairment of innate immune cells is a characteristic feature of HBeAg‐negative chronic hepatitis B

The mitogen‐activated protein kinase p38 (MAPK) is implicated in the induction of immune responses by regulating the differentiation of T lymphocytes and production of cytokines. Our aim was to investigate p38MAPK phosphorylation in different stages of the natural history of hepatitis B virus (HBV) infection. Peripheral blood mononuclear cells (PBMCs) were isolated by Ficoll‐Hypaque density‐based centrifugation from 10 patients with HBeAg‐negative chronic hepatitis B [HBeAg(?) CHB;HBV‐DNA>2000IU/mL], eight patients with HBeAg‐negative chronic HBV infection [HBeAg(?) CI;undetectable HBV‐DNA] and 8 healthy controls (HCs). p38MAPK phosphorylation was assessed by phospho‐specific flow cytometry in PBMCs and cell subsets (CD3+,CD3?,CD56+,CD56?) after stimulation with cytokines (IL‐12+IL‐2 and IL‐12+IL‐18) or nonspecific stimuli [arsenite, phorbol 12‐myristate 13‐acetate (PMA) and ionomycin] at 0,30,60,120 and 240 minutes using p38 phospho‐specific conjugated antibodies. ΙFN‐γ was determined by ELISA in PBMCs culture supernatants after stimulation with rhIL‐2, rhIL‐12 and rhIL‐18, with and without pre‐treatment with the p38 MAPK inhibitor, SB203580. HBeAg(?) CI patients showed the highest expression of phosphor‐p38 MAPK in total PBMCs and subpopulations compared to HBeAg(?) CHB and HCs. A striking impairment in p38 phosphorylation was noted in CD56+ cells and in especially in NK cells (CD3‐CD56+). SB203580‐induced inhibition of p38MAPK phosphorylation was associated with suppression of IFN‐γ production in all groups. The universal lack of p38 MAPK activation in CD56+ and in particular in NK cells from HBeAg(?) CHB patients during viremia suggests a potential cell‐dependent implication of this pathway in the natural history of HBV infection.