MK615 inhibits pancreatic cancer cell growth by dual inhibition of Aurora A and B kinases

AIM：To investigate the anti-neoplastic effect of MK615, an anti-neoplastic compound isolated from Japanese apricot, against human pancreatic cancer cells in vitro.
METHODS： Three human pancreatic cancer cell lines PANC-1, PK-1, and PK45H were cultured with MK615 at concentrations of 600, 300, 150, and 0 μg/mL. Growth inhibition was evaluated by cell proliferation assay, and killing activity was determined by lactate dehydrogenase （LDH） assay. Expression of Aurora A and B kinases was detected by real-time polymerase chain reaction （PCR） and Western blotting. Cell cycle stages were evaluated by flow cytometry.
RESULTS： The growth inhibitory rates of MK615 at 150, 300, and 600 μg/mL were 2.3% ± 0.9%, 8.9% ± 3.2% and 67.1% ± 8.1% on PANC1 cells, 1.3% ± 0.3%, 8.7% ± 4.1% and 45.7 ± 7.6% on PK1 cells, and 1.2 ± 0.8%, 9.1% ± 2.1% and 52.1% ± 5.5% on PK45H cells, respectively （P 〈0.05）. The percentage cytotoxicities of MK615 at 0, 150, 300, and 600 μg/mL were 19.6% ± 1.3%, 26.7% ± 1.8%, 25.5% ± 0.9% and 26.4% ± 0.9% in PANC1 cells, 19.7% ± 1.3%, 24.7% ± 0.8%, 25.9% ± 0.9% and 29.9% ± 1.1% in PK1 cells, and 28.0% ± 0.9%, 31.2% ± 0.9%, 30.4% ± 1.1% and 35.3 ± 1.0% in PK45H cells, respectively （P 〈 0.05）. Real-time PCR and Western blotting showed that MK615 dually inhibited the expression of Aurora A and B kinases. Cell cycle analysis revealed that MK615 increased the population of cells in G2/M phase.
CONCLUSION： MK615 exerts an anti-neoplastic effect on human pancreatic cancer cells in vitro by dual inhibition of Aurora A and B kinases.     

The Pim protein kinases regulate energy metabolism and cell growth

The serine/threonine Pim kinases are overexpressed in solid cancers and hematologic malignancies and promote cell growth and survival. Here, we find that a novel Pim kinase inhibitor, SMI-4a, or Pim-1 siRNA blocked the rapamycin-sensitive mammalian target of rapamycin (mTORC1) activity by stimulating the phosphorylation and thus activating the mTORC1 negative regulator AMP-dependent protein kinase (AMPK). Mouse embryonic fibroblasts (MEFs) deficient for all three Pim kinases [triple knockout (TKO) MEFs] demonstrated activated AMPK driven by elevated ratios of AMPATP relative to wild-type MEFs. Consistent with these findings, TKO MEFs were found to grow slowly in culture and have decreased rates of protein synthesis secondary to a diminished amount of 5'-cap-dependent translation. Pim-3 expression alone in TKO MEFs was sufficient to reverse AMPK activation, increase protein synthesis, and drive MEF growth similar to wild type. Pim-3 expression was found to markedly increase the protein levels of both c-Myc and the peroxisome proliferator-activated receptor gamma coactivator 1α (PGC-1α), enzymes capable of regulating glycolysis and mitochondrial biogenesis, which were diminished in TKO MEFs. Overexpression of PGC-1α in TKO MEFs elevated ATP levels and inhibited the activation of AMPK. These results demonstrate the Pim kinase-mediated control of energy metabolism and thus regulation of AMPK activity. We identify an important role for Pim-3 in modulating c-Myc and PGC-1α protein levels and cell growth.     

Activation of mitogen-activated protein kinases in different models of pancreatic acinar cell damage

Mitogen-activated protein kinase (MAPK) family members, namely MAPK, c-Jun NH2-terminal protein kinase (JNK), and p38MAPK, have been recently reported to have opposing effects on apoptosis. AIM: To determine the activity of MAPKs and the level of Bax, Bcl-2 and p53--proteins known to be involved in the regulation of apoptosis--in pancreatic acini subjected to stressful stimuli leading to cell death. METHODS AND RESULTS: Isolated pancreatic acini were irradiated for 30 min with ultraviolet B (UV-B) or stimulated with supraphysiological concentrations of cholecystokinin (CCK). As it was assessed by means of acridine orange/ethidium bromide staining, irradiation with UV-B induced predominantly apoptosis while necrosis predominated in CCK-stimulated acini. The activity of MAPK, JNK and p38MAPK was determined by means of Western-blotting, with the use of antibodies which recognize active, dually phosphorylated enzymes. Irradiation with UV-B induced a rapid, 3-fold increase in MAPK activity. It had a maximum at 30 min and then gradually declined to reach the normal level at 120 min. Concomitantly, early activation of p38-MAPK was found at 30 min. However, unlike MAPK, p38-MAPK activity was then gradually rising to reach a maximum (5-fold increase) at 180 min. UV-B-induced activation of both kinases was not affected by the pretreatment with antioxidant--N-acetylo-L-cysteine or protein kinase C inhibitor--GF-109203X. In UV-B-irradiated cells, we did not detect any significant JNK activation as well as any significant changes in Bax, Bcl-2 and p53 levels assessed by means of Western-blotting. CONCLUSION: It seems likely that a specific interaction between MAPK and p38MAPK signaling pathway may be involved in the determination of the cell death mechanism in pancreatic acini subjected to stressful stimuli.     

Stress-activated kinases as therapeutic targets in pancreatic cancer

Pancreatic cancer is a dismal disease with high incidence and poor survival rates. With the aim to improve overall survival of pancreatic cancer patients, new therapeutic approaches are urgently needed. Protein kinases are key regulatory players in basically all stages of development, maintaining physiologic functions but also being involved in pathogenic processes. c-Jun N-terminal kinases (JNK) and p38 kinases, representatives of the mitogen-activated protein kinases, as well as the casein kinase 1 (CK1) family of protein kinases are important mediators of adequate response to cellular stress following inflammatory and metabolic stressors, DNA damage, and others. In their physiologic roles, they are responsible for the regulation of cell cycle progression, cell proliferation and differentiation, and apoptosis. Dysregulation of the underlying pathways consequently has been identified in various cancer types, including pancreatic cancer. Pharmacological targeting of those pathways has been the field of interest for several years. While success in earlier studies was limited due to lacking specificity and off-target effects, more recent improvements in small molecule inhibitor design against stress-activated protein kinases and their use in combination therapies have shown promising in vitro results. Consequently, targeting of JNK, p38, and CK1 protein kinase family members may actually be of particular interest in the field of precision medicine in patients with highly deregulated kinase pathways related to these kinases. However, further studies are warranted, especially involving in vivo investigation and clinical trials, in order to advance inhibition of stress-activated kinases to the field of translational medicine.     

Targeting X-linked inhibitor of apoptosis protein inhibits pancreatic cancer cell growth through p-Akt depletion

AIM: To determine whether lentivirus-mediated shRNA targeting the X-linked inhibitor of apoptosis protein (XIAP) gene could be exploited in the treatment of pancreatic cancer.METHODS: Human pancreatic cancer cells Panc-1, Mia-paca2, Bxpc-3 and SW1990, infected with lentivirus, were analyzed by real-time polymerase chain reaction (PCR). Western blotting was used to examine XIAP protein levels, survivin and p-Akt to confirm the result of real-time PCR and determine the possible mechanism. The 3-(4,5-cimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay was used to measure IC₅₀ to determine chemosensitivity to the chemotherapeutic drugs 5-fluorouracil (5-FU) and gemcitabine. A colony assay, MTT assay and a tumorigenicity experiment were used to study cell proliferation in vitro and in vivo. Caspase-3/7 activity, 4'',6-diamidino-2-phenylindole-staining and flow cytometric measurements were used to study apoptosis in SW1990 cells.RESULTS: XIAP proteins were found to be differentially expressed among pancreatic cancer cell lines Panc-1, Mia-paca2, Bxpc-3 and SW1990. Data of real-time PCR and Western blotting showed that XIAP was reduced persistently and markedly by lentivirus-mediated shRNA. Downregulation of XIAP by transfection with XIAP shRNA resulted in decreased p-Akt expression. XIAP shRNA also inhibited the growth of pancreatic cancer cells in vitro and in vivo, enhanced drug-induced apoptosis and increased chemosensitivity to 5-FU and gemcitabine. Results also suggest that inhibition of XIAP and subsequent p-Akt depletion may have an anti-tumor effect through attenuating the ability of cancer cells to survive.CONCLUSION: Lentivirus-mediated gene therapy is an attractive strategy in the treatment of pancreatic cancer and justifies the use of lentivirus in pancreatic cancer gene therapy studies.     

Insulin-like growth factor binding protein-5 influences pancreatic cancer cell growth

AIM： To investigate the functional significance of insulin-like growth factor binding protein-5 （IGFBP-5） overexpression in pancreatic cancer （PaC）.
METHODS： The effects of IGFBP-5 on cell growth were assessed by stable transfection of BxPC-3 and PANC-1 cell lines and measuring cell number and DNA synthesis. Alterations in the cell cycle were assessed by flow cytometry and immunoblot analyses. Changes in cell survival and signal transduction were evaluated after mitogen and phosphatidylinositol activated protein kinase 3-kinase （PI3K） inhibitor treatment.
RESULTS： After serum deprivation, IGFBP-5 expression increased both cell number and DNA synthesis in BxPC-3 cells, but reduced cell number in PANC-1 cells. Consistent with this observation, cell cycle analysis of IGFBP-5-expressing cells revealed accelerated cell cycle progression in BxPC-3 and G2/M arrest of PANC-1 cells. Signal transduction analysis revealed that Akt activation was increased in BxPC-3, but reduced in PANC-1 cells that express IGFBP-5. Inhibition of PI3K with LY294002 suppressed extracellular signal-regulated kinase-1 and -2 （ERK1/2） activation in BxPC-3, but enhanced ERK1/2 activation in PANC-1 cells that express IGFBP-5. When MEK1/2 was blocked, Akt activation remained elevated in IGFBP-5 expressing PaC cells; however, inhibition of PI3K or MEK1/2 abrogated IGFBP-5-mediated cell survival.
CONCLUSION： These results indicate that IGFBP-5 expression affects the cell cycle and survival signal pathways and thus it may be an important mediator of PaC cell growth.     

华蟾素对人胰腺癌细胞BxPC3细胞增殖和细胞周期的影响

目的观察华蟾素（Cinobutacini）对人胰腺癌细胞株BxPC3的细胞增殖和细胞周期的影响并探讨其可能的作用机理。方法将不同浓度的华蟾素作用于人胰腺癌细胞株BxPC3,采用CCK-8法检测细胞增殖;流式细胞术检测细胞周期的变化。结果华蟾素明显抑制人胰腺癌细胞株BxPC3的细胞增殖,其作用随华蟾素浓度增加而增强伊〈0．05）;流式细胞术检测细胞周期发现,华蟾素可使人胰腺癌细胞株BxPC3阻滞于的S期。结论华蟾素能明显抑制人胰腺癌细胞株BxPC3的细胞增殖,可使肿瘤细胞阻滞于细胞周期的S期,阻止其进入分裂期,这可能是抑制细胞增殖的作用机理之一。     

c-Jun氨基末端激酶信号转导途径与胰岛β细胞凋亡

c-Jun N-terminal kinases (JNK) is one of the important members of mitogen activated protein kinase family. JNK pathway participates in the apoptosis of pancreatic beta ceil. Beta cell apoptosis can be induced by IL-1β,TNF-α/IFN-γ,and inhibited by exendin-4, L-isoform of JNK inhibitor. New target may be provided through regulating JNK signal pathway.     

c-Jun氨基末端激酶信号转导途径与胰岛β细胞凋亡

心脏是醛固酮作用的重要靶器官之一 ,而心脏本身也具有合成与分泌醛固酮的能力 ,后者以自分泌或(和 )旁分泌的形式调节心肌细胞的功能。心脏的心肌细胞、纤维细胞和血管内皮细胞包含的特异性盐皮质激素受体 ,在醛固酮介导的心血管系统病理生理变化中发挥重要作用。     

c-Jun氨基末端激酶信号转导途径与胰岛β细胞凋亡

c-Jun N-terminal kinases (JNK) is one of the important members of mitogen activated protein kinase family. JNK pathway participates in the apoptosis of pancreatic beta ceil. Beta cell apoptosis can be induced by IL-1β,TNF-α/IFN-γ,and inhibited by exendin-4, L-isoform of JNK inhibitor. New target may be provided through regulating JNK signal pathway.     

c-Jun氨基末端激酶信号转导途径与胰岛β细胞凋亡

c-Jun N-terminal kinases (JNK) is one of the important members of mitogen activated protein kinase family. JNK pathway participates in the apoptosis of pancreatic beta ceil. Beta cell apoptosis can be induced by IL-1β,TNF-α/IFN-γ,and inhibited by exendin-4, L-isoform of JNK inhibitor. New target may be provided through regulating JNK signal pathway.     

c-Jun氨基末端激酶信号转导途径与胰岛β细胞凋亡

c-Jun N-terminal kinases (JNK) is one of the important members of mitogen activated protein kinase family. JNK pathway participates in the apoptosis of pancreatic beta ceil. Beta cell apoptosis can be induced by IL-1β,TNF-α/IFN-γ,and inhibited by exendin-4, L-isoform of JNK inhibitor. New target may be provided through regulating JNK signal pathway.     

促甲状腺素受体抗体检测的临床意义

促甲状腺素受体抗体 (TRAb)与多种自身免疫性甲状腺疾病的发病密切相关 ,是临床诊断这些疾病的重要指标。TRAb在功能上可分为甲状腺刺激性抗体 (TSAb)和甲状腺刺激阻断性抗体(TSBAb) ,可与促甲状腺素受体分子上不同位点结合产生不同生物学效应。其中TSAb可引起Graves病 (GD)患者甲状腺功能亢进和弥漫性甲状腺肿的发生 ,而TSBAb则可导致自身免疫性甲状腺功能减退症 (甲减 )患者甲减的发生。本文将对TRAb检测在GD鉴别诊断、辅助制定GD治疗方案、抗甲状腺药物疗效及预测复发、筛查自身免疫性甲减等方面的临床价值作一全面综述。     

c-Jun氨基末端激酶信号转导途径与胰岛β细胞凋亡

c-Jun N-terminal kinases (JNK) is one of the important members of mitogen activated protein kinase family. JNK pathway participates in the apoptosis of pancreatic beta ceil. Beta cell apoptosis can be induced by IL-1β,TNF-α/IFN-γ,and inhibited by exendin-4, L-isoform of JNK inhibitor. New target may be provided through regulating JNK signal pathway.     

c-Jun氨基末端激酶信号转导途径与胰岛β细胞凋亡

甲状腺激素受体 (TR)为配体依赖性转录因子。未结合T3 的TR与辅阻遏因子等形成复合物 ,此复合物通过使局部的组蛋白去乙酰化而使局部染色质变得紧密 ,进而抑制靶基因的基础转录。结合了T3 的TR与辅阻遏因子解离 ,转录恢复到基础水平。随后辅激活因子与结合了T3 的TR形成复合物 ,此复合物通过使组蛋白乙酰化而使局部染色质变得松弛 ,进而激活靶基因的转录。辅激活因子复合物还能使RNA聚合酶稳定 ,从而促进转录