阿司匹林通过诱导JNK表达促进其磷酸化抑制肺癌PC14细胞增殖

目的：观察阿司匹林对肺癌PC14细胞的作用及其可能机制。方法：用0，4，8，16 mmol·L^-1阿司匹林处理PC14细胞24，48，72 h，用MTT法和流式细胞术检测细胞增殖及凋亡。为研究其与c-Jun氨基末端激酶（JNK）活化间的关系，先以5 μmol·L^-1 SP600125（JNK抑制剂）预处理PC14细胞30 min，加入上述浓度药物继续培养24，48，72 h，检测细胞增殖情况；Western blot检测阿司匹林对JNK活化的影响。结果：MTT结果显示阿司匹林抑制肺癌PC14细胞增殖，同时阿司匹林可引起细胞G0~G1阻滞；阿司匹林通过活化JNK诱导其表达抑制PC14增殖。结论：阿司匹林可抑制PC14细胞增殖，其机制可能与其增强JNK活化及表达有关，这为阿司匹林在肺癌治疗中的进一步应用提供了理论依据。     

GD1a对基质金属蛋白酶-9在不同细胞类型中表达的调控作用

目的在不同的细胞类型中,检测神经节苷脂GD1a是否抑制基质金属蛋白酶-9(MMP-9)的表达。方法采用逆转录PCR法和酶谱法检测MMP-9及MMP-2的表达。结果在鼠黑色素瘤B16细胞中,神经节苷脂GD1a促进MMP-9的表达,而在小鼠肺癌Lewis细胞、人单核细胞THP-1及人子宫颈癌HeLa细胞中,神经节苷脂GD1a降低MMP-9的表达。在上述细胞中,神经节苷脂GD1a不影响基质金属蛋白酶MMP-2的表达;肿瘤坏死因子TNF-α在这几种细胞中均能促进MMP-9的表达,但对MMP-2无影响;在B16细胞中,GD1a通过胞窖膜介导信号传递,并且主要通过ERK促进MMP-9的表达,而在Lewis细胞中,GD1a不通过胞窖膜介导信号传递,但部分通过p38、ERK和JNK抑制MMP-9表达。结论在不同的细胞类型中,神经节苷脂GD1a能够激活不同的信号转导途径。     

Role of oxidative stress and MAPK signaling in reference moist smokeless tobacco-induced HOK-16B cell death

The use of smokeless tobacco products is often associated with an oral injury at the site of repeated use. To further our understanding of this injury process, the effect of reference moist smokeless tobacco extract (STE) on cell death, oxidative stress, and MAPK signaling in a human oral keratinocyte cell line, HOK-16B, was investigated. STE caused dose-dependent cell death and reactive oxygen species (ROS) production within 30 min to 3 h of exposure. This same insult enhanced the activity of ERK1/2, JNK1/2, p38 MAPK and ASK1, an upstream activator of JNK1/2 and p38 MAPK. Inhibition of JNK1/2 and to a lesser extent p38 MAPK, but not ERK1/2, suppressed STE-induced cell death. Pretreatment with antioxidants and an iron chelator, deferoxamine suppressed ROS production, ASK1, JNK1/2 and p38 MAPK activation, and reduced cell death after STE exposure. Interestingly, extracellular free iron levels in STE (29.4 ± 0.5 μM) were significantly elevated as compared with cell culture medium (4.9 ± 0.6 μM) and the addition of extracellular free iron (14, 30 or 70 μM) to HOK-16B cultures (without STE) caused dose-dependent cell death after 3 h. Thus, acute exposure to STE leads to HOK-16B cell death in part through oxidative stress via activation of ASK1 and the JNK1/2 and p38 MAPK pathways.     

Aspirin and sodium salicylate inhibit proliferation and induce apoptosis in rheumatoid synovial cells

Aspirin has been reported to induce apoptosis in a variety of cell lines. In this study, we examined whether aspirin and sodium salicylate inhibit cell growth and induce apoptosis in rheumatoid synovial cells. Synovial cells were obtained from patients with rheumatoid arthritis, and the cells were treated with aspirin or sodium salicylate (0.1-10 mM) for 24 h. Cell proliferation and viability were assessed by 5-bromo-2'-deoxyuridine incorporation and by 4-[3-(4-iodophenyl)-2-(4-nitrophenyl)-2H-5-tetrazolio]-1,3-benzene disulfonate (WST-1) assay, respectively. The apoptosis of synovial cells was identified by DNA fragmentation assay and terminal deoxynucleotidyl transferase-mediated dUTP nick end labelling (TUNEL) assay. Aspirin and sodium salicylate suppressed the proliferation (IC50 (concentration causing 50% inhibition of cell proliferation): 2.1 and 1.2 mM, respectively) and reduced the viability (IC50: 2.0 and 1.4 mM, respectively) of synovial cells in a concentration-dependent manner at 0.3-10 mM. Furthermore, they induced DNA fragmentation and increased the number of TUNEL-positive synovial cells. These results suggest that aspirin and sodium salicylate can inhibit the proliferation of rheumatoid synovial cells through induction of apoptosis.     

Biphasic effect of cadmium on cell proliferation in human embryo lung fibroblast cells and its molecular mechanism

Hormesis, a biphasic dose–response phenomenon, is characterized by a low-dose stimulation and a high-dose inhibition. However, the mechanisms underlying hormesis induced by environmental agents are not well elucidated. The present study was to investigate the relationship between the hormesis effect of cadmium (Cd) and activation of ERK1/2, JNK and p38 pathways in human embryo lung fibroblast cells. Results showed that Cd induced significant cell proliferation at low concentrations, but markedly inhibited cell growth at high concentrations. Our data indicated that cell proliferation promoted by low concentrations of Cd was blocked obviously by ERK1/2 inhibitor PD98059 and partly by JNK inhibitor SP600125; while the decreases of cell proliferation induced by high concentrations of Cd were significantly restored by p38 inhibitor SB203580. Further analysis showed that phospho-ERK1/2 and phospho-JNK activities were increased with different concentrations of Cd, whereas phospho-p38 activity was markedly increased at high concentrations. Our findings suggested that low concentration of Cd induces the ERK and JNK pathways and promotes cell proliferation; while high concentration of Cd induces p38 pathway and inhibits cell proliferation. Activation of the ERK1/2 pathways seems to play a more important role than the JNK pathway in the biphasic effect of Cd on cell proliferation.     

Antimetastatic effect of an immunomodulatory arabinomannan extracted from Mycobacterium tuberculosis strain Aoyama B,Z-100, through the production of interleukin-12

In this study, the role of interleukin (IL)-12 on the antimetastatic effect of Z-100 was investigated using wild-type C57BL/6 mice or IL-12p40 knockout (IL-12p40 KO) mice inoculated with highly metastatic B16F10 melanoma. When C57BL/6 mice were inoculated with B16F10 melanoma (2x10(5) cells/mouse i.v.), Z-100 (10 mg/kg i.p.) significantly suppressed the pulmonary metastasis of B16F10 melanoma 14 d after tumor inoculation. On the other hand, the antimetastatic effect of Z-100 was not observed in IL-12p40 KO mice inoculated with B16F10 melanoma. These results indicate that IL-12 is essentially required for the appearance of the antimetastatic effect of Z-100. Since helper T (Th) 2 cell responses have been reported to have a role in tumor metastasis, the regulatory effect of Z-100 on the immune balance of Th1/Th2 cell responses was investigated. In both C57BL/6 mice and IL-12p40 KO mice bearing B16F10 melanoma, Th1 cytokine production (IL-2, interferon-gamma) was significantly suppressed as compared with those in normal mice. On the other hand, Th2 cytokine production (IL-4, IL-10) in these mice was increased. The administration of Z-100 (10 mg/kg i.p.) in C57BL/6 mice bearing B16F10 melanoma improved the balance of Th1/Th2 cell responses from the Th2-dominant state to the normal state. However, the improvement of Th1/Th2 cell responses by Z-100 was not observed in IL-12p40 KO mice bearing the same tumors. In addition, Z-100 significantly increased IL-12 production by macrophages in a concentration-dependent manner, while Z-100 significantly decreased IL-10 production by these cells in vitro. These results suggested that up-regulation of IL-12 production and down-regulation of IL-10 production by Z-100 are related to the improvement of Th1/Th2 cell responses from the Th2-dominant state to the normal state, which resulted in suppression of tumor metastasis.     

P-选择素对黑色素瘤细胞整合素β_1表达的影响

目的：研究P-选择素对黑色素瘤细胞整合素β1表达的影响,探讨P-选择素在肿瘤转移中的作用。方法：培养黑色素瘤细胞B16F10,在加或不加p38丝裂原活化蛋白激酶（MAPK）抑制剂SB203580的情况下,用P-选择素蛋白进行刺激,用蛋白质印迹（Western Blot）检测刺激后B16F10细胞整合素β1蛋白表达及p38 MAPK信号分子磷酸化水平的改变,用MTT法检测黏附细胞数目的变化。结果：P-选择素刺激B16F10细胞导致p38 MAPK磷酸化水平增高,整合素β1表达上调,用特异性阻断剂阻断p38 MAPK活化可以抑制P-选择素的诱导作用。MTT检测结果显示P-选择素刺激可增加细胞与整合素β1配基纤维粘连蛋白的黏附能力,说明细胞整合素β1表达增高。结论：P-选择素可以通过激活p38 MAPK途径诱导黑色素瘤B16F10细胞整合素β1的表达,提高肿瘤细胞的黏附能力,这可能是其促进肿瘤转移的机制之一。     

Suppression of the migration and invasion is mediated by triptolide in B16F10 mouse melanoma cells through the NF‐kappaB‐dependent pathway

Melanoma cancer is one of the major causes of death in humans worldwide. Triptolide is one of the active components of Tripterygium wilfordii Hook F, and has biological activities including induced cell cycle arrest and induction of apoptosis but its antimetastatic effects on murine melanoma cells have not yet been elucidated. Herein, we investigated the effect of triptolide on the inhibition of migration and invasion and possible associated signal pathways in B16F10 murine melanoma cancer cells. Wound healing assay and Matrigel Cell Migration Assay and Invasion System demonstrated that triptolide marked inhibiting the migration and invasion of B16F10 cells. Gelatin zymography assay demonstrated that triptolide significantly inhibited the activities of matrix metalloproteinases‐2 (MMP‐2). Western blotting showed that triptolide markedly reduced CXCR4, SOS1, GRB2, p‐ERK, FAK, p‐AKT, Rho A, p‐JNK, NF‐κB, MMP‐9, and MMP‐2 but increased PI3K and p‐p38 and COX2 after compared to the untreated (control) cells. Real time PCR indicated that triptolide inhibited the gene expression of MMP‐2, FAK, ROCK‐1, and NF‐κB but did not significantly affect TIMP‐1 and ‐2 gene expression in B16F10 cells in vitro. EMSA assay also showed that triptolide inhibited NF‐κB DNA binding in a dose‐dependent manner. Confocal laser microscopy examination also confirmed that triptolide inhibited the expression of NF‐κB in B16F10 cells. Taken together, we suggest that triptolide inhibited B16F10 cell migration and invasion via the inhibition of NF‐κB expression then led to suppress MMP‐2 and ‐9 expressions. © 2015 Wiley Periodicals, Inc. Environ Toxicol 31: 1974–1984, 2016.     

Antimetastatic potential of vernolide-A, a sesquiterpenoid from Vernonia cinerea L

The inhibitory effect of vernolide-A (C(21)H(28)O(7)) on lung metastasis induced by B16F-10 melanoma cells was studied using C57BL/6 mice. Vernolide-A was administered in three different modalities such as simultaneously with tumor, prophylactic to tumor and after tumor development. Maximum inhibition in the metastasis was observed when vernolide-A was administered simultaneously with tumor. There was 89.39% inhibition of lung tumor nodule formation and 88.51% increase in the life span of metastatic tumor-bearing animals. Highly elevated levels of lung hydroxyproline, lung uronic acid, lung hexosamine, serum sialic acid, serum γ-glutamyl transpeptidase (GGT) and serum vascular endothelial growth factor (VEGF) in the metastatic control animals were found to be significantly lowered in the vernolide-A-treated animals. Histopathological analysis of lung tissues also correlated with these results. Vernolide-A administration downregulated the expression of matrix metalloproteinase-2 (MMP-2), MMP-9, extracellular-signal-regulated kinase-1 (ERK-1), ERK-2 and VEGF in the lung tissue of B16F-10 melanoma challenged animals. In the in vitro system, vernolide-A showed a significant inhibition of invasion of B16F-10 melanoma cells across the collagen matrix. Vernolide-A treatment also inhibited the migration of B16F-10 melanoma cells across a polycarbonate filter in vitro. Vernolide-A could inhibit MMP-2 and MMP-9 protein expression in gelatin zymographic analysis of B16F-10 cells. (3)H-thymidine proliferation assay showed that vernolide-A could inhibit the proliferation of B16F-10 melanoma cells in vitro. These results indicate that vernolide-A could inhibit the metastatic progression of B16F-10 melanoma cells in mice.     

JNK1 is required for sulindac-mediated inhibition of cell proliferation and induction of apoptosis in vitro and in vivo

Our previous studies demonstrated that sulindac, a non-steroidal anti-inflammatory drug, suppressed intestinal tumor formation in mouse, which is linked to the induction of wild-type p53-activated fragment 1 (p21WAF1, or p21). Here we showed that sulindac also required c-Jun N-terminal Kinase 1 (JNK1) to inhibit cell proliferation and induce apoptosis in vitro and in vivo. First, sulindac inhibited cell proliferation and induced apoptosis in colon cancer cell lines HCT116 with wild-type p21 or null p21, which were p21-dependent and were also associated with the induction of p21 and phosphorylation of JNK1. Second, sulindac increased apoptosis in JNK1^+/+ and JNK1^−/− mouse embryonic fibroblast (MEF) cells, but, the increase of apoptosis in JNK1^+/+ cells was more than that in JNK1^−/− cells. More interestingly, sulindac significantly inhibited cell proliferation in JNK1^+/+ cells, but the inhibition in JNK1^−/− cells markedly decreased. Further studies indicated that JNK1 was dramatically induced by sulindac in the JNK1^+/+ cells which correlated with the induction of p21. However, the induction of p21 in JNK1^−/− cells was less than that in JNK1^+/+ cells. Finally, we determined the expression of JNK1 in the intestinal mucosa of Apc^+/−, p21^+/+ mice, and found that sulindac significantly induced JNK1 phosphorylation, corresponding to the induction of p21, both in mRNA and protein levels. Our data indicates that sulindac-mediated proliferation inhibition and apoptosis induction were not only p21-dependent, but also required JNK1.     

阿司匹林抑制ox-LDL诱导内皮细胞炎症分子表达的研究

目的评价阿司匹林对ox-LDL刺激内皮细胞炎症蛋白表达的影响。方法使用培养人脐带内皮细胞,用氧化型低密度脂蛋白刺激内皮细胞16h,终止反应后用SDS-PAGE分离蛋白,使用Western Blot分析蛋白表达的变化。ROS测定使用DCFH-DA荧光标记,用流式细胞仪测定荧光强度。结果①阿司匹林抑制ox-LDL诱导内皮细胞COX-2表达。使用ox-LDL刺激内皮细胞16h,COX-2表达增加,分别用2.5mmol·L-1和5mmol·L-1阿司匹林处理内皮细胞30min后,COX-2表达明显降低。②阿司匹林降低ox-LDL诱导的内皮细胞ICAM-1表达。ox-LDL刺激内皮细胞16h后,Western Blot结果显示ICAM-1内皮细胞表达明显增加。用免疫荧光染色的方法观察细胞获得了同样的结果,ox-LDL刺激后ICAM-1在内皮细胞膜上表达明显增加,阿司匹林处理后减少了ICAM-1在膜上的表达。③阿司匹林轻度抑制ox-LDL诱导内皮细胞ROS产生。0.3g·L-1ox-LDL刺激内皮细胞16h后细胞内ROS明显增高,但阿司匹林仅部分阻止ROS的产生。结论非甾体类抗炎药物阿司匹林对ox-LDL诱导COX-2、ICAM-1有明显的抑制作用,但不能完全阻止ox-LDL诱导的ROS产生。这些结果表明阿司匹林能够减轻氧化脂质诱导的内皮细胞炎症损伤反应。     

Biphasic effect of aspirin on apoptosis of bovine vascular endothelial cells and its molecular mechanism

AIM: To investigate the effect of aspirin on the apoptosis of cultured bovine aortic endothelial cells (BAEC) and the signal pathways involved in this process. METHODS: BAEC were cultured and passaged in Dulbecco's modified Eagle's medium culture medium. Morphologic changes and quantification of apoptotic cells were determined using fluorescence microscope after staining the cells with Hoechst 33258. Cell viability was measured by 3-[4,5-dimethylthiazol-2-yl]-2,5- diphenyltetrazolium bromide (MTT) method. DNA fragmentation was visualized by agarose gel electrophoresis. Phospho-p38 mitogen-activated protein kinase (MAPK) expression was detected by Western blotting. RESULTS: Aspirin at low concentrations from 1X10( -10) mol/L to 1X10( -8) mol/L decreased the apoptosis and p38 MAPK phosphorylation induced by H2O2 in BAEC, while high doses of aspirin (1X10( -7)-1X10( -4) mol/L) induced typical apoptotic changes in BAEC and stimulated the expression of phospho-p38 MAPK in a concentration-dependent manner. SB203580, a specific p38 MAPK inhibitor, blocked such effects. CONCLUSION: Aspirin exhibits a biphasic effect on the apoptosis in BAEC, reducing apoptosis at low concentration and inducing apoptosis at high concentration. p38 MAPK may be an important signal molecule mediating the effects of aspirin.     

Guggulsterone inhibits tumor cell proliferation, induces S-phase arrest, and promotes apoptosis through activation of c-Jun N-terminal kinase, suppression of Akt pathway, and downregulation of antiapoptotic gene products

Guggulsterone is a plant polyphenol traditionally used to treat obesity, diabetes, hyperlipidemia, atherosclerosis, and osteoarthritis, possibly through an anti-inflammatory mechanism. Whether this steroid has any role in cancer is not known. In this study, we found that guggulsterone inhibits the proliferation of wide variety of human tumor cell types including leukemia, head and neck carcinoma, multiple myeloma, lung carcinoma, melanoma, breast carcinoma, and ovarian carcinoma. Guggulsterone also inhibited the proliferation of drug-resistant cancer cells (e.g., gleevac-resistant leukemia, dexamethasone-resistant multiple myeloma, and doxorubicin-resistant breast cancer cells). Guggulsterone suppressed the proliferation of cells through inhibition of DNA synthesis, producing cell cycle arrest in S-phase, and this arrest correlated with a decrease in the levels of cyclin D1 and cdc2 and a concomitant increase in the levels of cyclin-dependent kinase inhibitor p21 and p27. Guggulsterone-induced apoptosis as indicated by increase in the number of Annexin V- and TUNEL-positive cells, through the downregulation of anti-apoptototic products. The apoptosis induced by guggulsterone was also indicated by the activation of caspase-8, bid cleavage, cytochrome c release, caspase-9 activation, caspase-3 activation, and PARP cleavage. The apoptotic effects of guggulsterone were preceded by activation of JNK and downregulation of Akt activity. JNK was needed for guggulsterone-induced apoptosis, inasmuch as inhibition of JNK by pharmacological inhibitors or by genetic deletion of MKK4 (activator of JNK) abolished the activity. Overall, our results indicate that guggulsterone can inhibit cell proliferation and induce apoptosis through the activation of JNK, suppression of Akt, and downregulation of antiapoptotic protein expression.     

Irciniastatin A induces JNK activation that is involved in caspase-8-dependent apoptosis via the mitochondrial pathway

Irciniastatin A (ISA)/psymberin, a pederin-type natural product isolated from marine sponge, exhibits extremely potent and selective cytotoxicity against certain human cancer cell lines, but its molecular target and cytotoxic mechanisms are still unknown. Here we show that ISA is a potent inhibitor of protein translation, and induces apoptosis accompanied with activation of the stress-activated protein kinases via the mitochondrial pathway in human leukemia Jurkat cells. ISA potently inhibited protein translation, and induced a slow but prolonged activation of the stress-activated protein kinases, JNK and p38, at between 1h and 6h after treatment. In Bcl-x(L)-transfected cells, the activation of JNK and p38 by ISA was shortened. The same results were obtained in the cells treated with N-acetyl-L-cysteine, suggesting that the prolonged activation of JNK and p38 by ISA is mediated by reactive oxygen species generated from mitochondria. ISA strongly induced apoptosis, which was partially suppressed by the JNK inhibitor SP600125, but not by the p38 inhibitor SB202190. Apoptosis induction by ISA was partially reduced, but not suppressed by SP600125 in caspase-8-deficient Jurkat cells. These results suggest that ISA activates stress-activated kinases by a mitochondria-mediated mechanism, and that activation of JNK is required for caspase-8-dependent apoptosis.     

Suppression of macrophage function by substances with a molecular weight lower than 3000 Da in B16 melanoma-conditioned medium

In the present study, B16 melanoma cells were found to produce inhibitory and cytotoxic substances with a molecular weight lower than 3000 Da against macrophages in a conditioned medium. The B16 melanoma-conditioned medium suppressed nitric oxide (NO) production only by mouse peritoneal macrophages and the mouse macrophage-like cell line, RAW264.7 cells, but not by rat peritoneal macrophages. In addition, it showed cytotoxicity against mouse peritoneal macrophages and mouse macrophage-like cell lines, RAW264.7 and J774A.1 cells, but not against rat cells (peritoneal macrophages, 3Y1, hepatocytes), human cells (HeLa, KB, MCF-7), or mouse 3T3-L1 cells. The inhibitory activity of NO production was not affected by trypsin treatment or arginine supplementation, but it was abolished by heat treatment at 95 degrees C for 3 min. On the other hand, the cytotoxicity was not influenced by these treatments. Inducible NO synthase induction following lipopolysaccharide stimulation was reduced by treatment of mouse peritoneal macrophages with B16 melanoma-conditioned medium. These results suggest that metastatic B16 melanoma cells produce two distinct substances: to suppress NO production by macrophages and to kill macrophages and macrophage-like cell lines. We propose that these activities may help metastatic B16 melanoma cells to escape a host immunosurveillance system and to metastasize to target organs.     

Protective effects of aspirin against oxidized LDL-induced inflammatory protein expression in human endothelial cells

Atherosclerosis is a complex vascular inflammatory disease. Oxidized low-density lipoprotein (ox-LDL) is directly associated with chronic vascular inflammation. In this study, we hypothesized that nonselective cyclooxygenase inhibitor aspirin might affect the ox-LDL-induced inflammatory responses on human endothelial cells. To test this assumption, cyclooxygenase-2 (COX-2) and intercellular adhesion molecule-1 (ICAM-1) expression, IkappaB and p38 mitogen-activated protein kinase (MAPK) phosphorylation were determined in endothelial cells exposed to ox-LDL in the presence of aspirin. The results showed that aspirin significantly suppressed COX-2 and ICAM-1 expression induced by ox-LDL and also inhibited IkappaB phosphorylation in human umbilical vein endothelial cells (HUVECs). Moreover, aspirin reduced the level of p38 MAPK phosphorylation. Our findings suggest that aspirin can decrease inflammatory responses induced by ox-LDL, and the mechanism might be associated with NF-kappaB activation pathway and inhibition of p38 MAPK phosphorylation.     

Activation of Jun N-terminal kinase is a mediator of vincristine-induced apoptosis of melanoma cells

The molecular changes involved in the induction of apoptosis by vincristine in melanoma have not yet been well defined. Two human melanoma cell lines showing moderate (Mel-RM) and high (IgR3) sensitivity to vincristine were selected from a panel of eight melanoma lines for analysis. Induction of apoptosis was caspase dependent, and was associated with increases in mitochondrial membrane permeability. Vincristine upregulated the expression of Bax, Bak, PUMA, Noxa, p53 and p21 proteins, and downregulated and/or phosphorylated the Bcl-2 protein. Inhibitors of the Jun N-terminal kinase (JNK), but not p38 mitogen-activated protein kinase, significantly inhibited vincristine-induced apoptosis in both IgR3 and Mel-RM cells. In addition, vincristine induced phosphorylation and reduction in Bcl-2 was prevented by an inhibitor of JNK. Downregulation of mRNA for p53, PUMA or Bim by RNA interference had little or no influence on vincristine-induced apoptosis in IgR3 cells. In addition, silencing Bim mRNA did not affect vincristine-induced apoptosis in Mel-RM cells. These results suggest that vincristine-induced apoptosis of at least some melanoma cell lines is dependent on the activation of JNK. The results are consistent with the phosphorylation of Bcl-2 protein, resulting in the activation of Bax/Bak, release of cytochrome c from the mitochondria and the resulting activation of caspases.