新型抗肝癌化合物CBI-5725对RAF/MEK/ERK通路及癌细胞凋亡的影响

目的评价一种新型的化合物CBI-5725对人类肝癌细胞系PLC/PRF/5的抗癌作用,并通过与治疗肝癌的靶向药物索拉非尼(Sorafenib)对比,揭示CBI-5725的作用机制。方法用AlarmaBlue法检测并比较CBI-5725或索拉非尼对肝癌细胞的抑制作用。采用Western blot法检测CBI-5725或索拉非尼对肝癌细胞中RAF/MEK/ERK通路磷酸化的影响。采用Annexin V-FITC/PI双染色法检测CBI-5725或索拉非尼对细胞凋亡的影响,采用Western blot法检测CBI-5725或索拉非尼对caspase-3和PARP的影响。采用小鼠肿瘤模型检验CBI-5725的体内抗肿瘤活性。结果与索拉非尼相比,CBI-5725更能有效抑制肝癌细胞的增殖,诱导细胞凋亡,激活caspase-3和PARP。此外,CBI-5725与索拉非尼相同程度地抑制RAF/MEK/ERK信号通路的磷酸化。在PLC/PRF/5小鼠肿瘤模型中,在6～18 mg/kg的剂量范围内,CBI-5725几乎完全抑制肿瘤生长。结论 CBI-5725可能作为一种有效的抗肿瘤药物替代索拉非尼用于肝癌患者的治疗,其机制与抑制RAF/MEK/ERK信号通路、启动caspase-3诱导的细胞凋亡有关。     

BCR-ABL1抑制剂与MEK抑制剂联用治疗耐药性慢性粒细胞白血病

抑制引起慢性粒细胞白血病（CML）的致癌激酶BCR-ABL1是临床上靶向治疗的成功典范,但在临床治疗中却频繁出现耐药性突变。一项新的研究表明,抑制耐药性BCR-ABL1突变可能会适得其反地将致癌信号激活,提出了克服耐药的协同战略。研究人员对几种蛋白抑制剂对表达致癌基因NRASQ61L的人黑素瘤细胞的影响进行了研究,结果发现,BCR—ABLl抑制剂伊马替尼、尼洛替尼和达沙替尼反而高度激活RAF．MEK．ERK激酶通路的致癌信号。这也发生于KRAS突变激活的细胞中。     

小分子酪氨酸激酶抑制剂安罗替尼对鼻咽癌细胞的抗肿瘤活性及其机制

目的 探索小分子酪氨酸激酶抑制剂安罗替尼对鼻咽癌细胞的抗肿瘤作用及其潜在机制,为临床应用安罗替尼治疗鼻咽癌提供可靠的实验证据。方法 通过CCK-8实验和克隆形成实验检测不同剂量梯度安罗替尼对鼻咽癌细胞6-10B和SUNE-1的细胞活性、增殖能力的影响;通过Transwell和划痕实验分析安罗替尼对鼻咽癌细胞侵袭及迁移能力的影响;利用流式细胞术检测安罗替尼对鼻咽癌细胞周期及凋亡的影响;采用Western blotting验证安罗替尼处理后鼻咽癌细胞凋亡相关蛋白的表达变化。结果 在鼻咽癌细胞中加入安罗替尼处理后,6-10B实验组和SUNE-1实验组细胞存活分数降低,细胞集落形成数量明显减少,且呈显著的剂量依赖性,在药物浓度为2.0μmol·L^-1时可达到约50%的增殖及克隆抑制率(P<0.01)。Western blotting分析发现,安罗替尼可能是由Erk通路介导线粒体通路激活,促进鼻咽癌细胞凋亡,且以药物浓度达到2.0μmol·L^-1时作用最为明显。凋亡检测结果证实,2.0μmol·L^-1安罗替尼处理后的实验组较...     

吉非替尼和依维莫司对EGFR-TKI耐药鼻咽癌细胞的作用简

摘要 目的 探讨吉非替尼和依维莫司对吉非替尼耐药鼻咽癌细胞的作用效果及分子作用机制。方法吉非替尼、依维莫司单独或联合作用人鼻咽癌细胞株HONE1后,采用噻唑蓝（MTT）法检测细胞的增殖抑制,流式细胞术检测细胞凋亡率及周期分布,Western blot检测细胞磷酸化丝氨酸苏氨酸蛋白激酶（p AKT）、磷酸化核糖体S6蛋白激酶（p S6K）的表达水平。结果吉非替尼和依维莫司均呈浓度依赖性抑制HONE1细胞增殖,吉非替尼的半数抑制浓度（IC50）为17.92 μmol&#8226;L－1,依维莫司的IC50为2.46 nmol&#8226;L－1,但二者联合作用效果与单药相比并未表现出明显的优势（P＞0.05）;吉非替尼对p AKT抑制作用不明显,依维莫司可下调p S6K的表达,同时上调了p AKT的表达,联合用药对p S6K和p AKT表达的抑制作用并不明显强于单药。结论吉非替尼和依维莫司联合作用于吉非替尼耐药鼻咽癌细胞株HONE1没有表现出协同效应,表皮生长因子受体/丝氨酸苏氨酸蛋白激酶（EGFR/AKT）信号通路与雷帕霉素蛋白（mTOR）信号通路在鼻咽癌细胞中的关系有待进一步研究。     

MAPK/ERK信号通路在益气解毒方水提物诱导鼻咽癌细胞凋亡中的作用

目的研究益气解毒方水提物对鼻咽癌细胞凋亡的影响,并从MAPK/ERK信号通路探讨其诱导凋亡的作用机制。方法 CCK-8法检测益气解毒方水提物对CNE1、CNE2细胞增殖的影响;Hoechst 33342染色法、JC-10染色法、荧光双染流式细胞仪检测其对CNE1、CNE2细胞凋亡的影响;Western blot法检测其对CNE1、CNE2细胞蛋白表达的影响。结果益气解毒方水提物能抑制CNE1、CNE2细胞增殖(P<0.05)、诱导凋亡(P<0.05);药物作用48 h后,Survivin、XIAP、Bcl-2表达下降,Bax表达上升,MAPK/ERK信号通路关键蛋白p-c-Raf、p-MEK、p-ERK表达下降(P<0.05);在此基础上,加入激活剂ISO和益气解毒方水提物后,与单用益气解毒方水提物相比,p-c-Raf、p-MEK、p-ERK1/2表达上调,Survivin、XIAP、Bcl-2表达增加,Bax表达下降,促凋亡效应也降低(P<0.05)。结论益气解毒方水提物可诱导鼻咽癌细胞凋亡,该效应与其抑制MAPK/ERK信号通路关键蛋白p-c-Raf、p-MEK、p-ERK1/2表达,进而下调Survivin、XIAP、Bcl-2表达,上调Bax表达有关。     

沙参麦冬汤通过调节EGFR/MEK/ERK信号通路对非小细胞肺癌细胞增殖、凋亡和自噬的影响

摘要：目的:探讨沙参麦冬汤（ROD）对非小细胞肺癌（NSCLC）细胞增殖、凋亡和自噬的影响,并分析其潜在机制。方法:制备ROD含药血清,体外培养人NSCLC细胞株A549,MTT法检测不同浓度的ROD含药血清对A549细胞活力的影响,筛选合适的干预浓度;将A549细胞随机分为空白组、阿法替尼组、20%ROD组、20%ROD+EGFR激活剂NSC 228155组;给予相应的干预后,采用细胞集落形成实验检测细胞增殖能力,流式细胞术分析细胞凋亡情况,GFP-LC3转染检测细胞自噬情况,蛋白质印迹（Western blot）检测细胞增殖、凋亡、自噬和表皮生长因子受体（EGFR）/丝裂原活化蛋白激酶激酶（MEK）/细胞外调节蛋白激酶（ERK）通路相关蛋白表达。结果:ROD含药血清可抑制A549细胞增殖,且20%ROD含药血清对A549细胞活力的抑制作用最显著（P＜0.05）。20%ROD含药血清可显著减少细胞集落数,升高细胞凋亡率,增加GFP-LC3斑点数,并降低Ki-67、p62蛋白水平和p-EGFR/EGFR、p-MEK/MEK和p-ERK/ERK比值,升高Cleaved Caspase-3/Caspase-3和LC3II/LC3I比值（P＜0.05）;EGFR抑制剂Afatinib对A549细胞增殖、凋亡、自噬和EGFR/MEK/ERK通路的作用与ROD含药血清相似;使用NSC 228155激活EGFR/MEK/ERK通路可显著减弱ROD含药血清对A549细胞凋亡和自噬的诱导作用以及对细胞增殖的抑制作用（P＜0.05）。结论:ROD含药血清可有效抑制A549细胞增殖,并诱导细胞凋亡、自噬,其作用机制可能与抑制EGFR/MEK/ERK通路有关。     

脂氧合酶抑制剂对肝癌细胞株HepG2增殖及MEK/ERK信号通路的影响

目的:探讨脂氧合酶抑制剂去甲二氢愈创木酸(NDGA)对肝癌细胞株HepG2增殖及MEK/ERK信号通路的影响.方法:在不同浓度的NDGA干预下对HepG2细胞进行体外培养;应用MTT比色法观察NDGA对HepG2增殖的影响;逆转录PCR( RT-PCR)测定不同浓度NDGA干预下丝裂原活化蛋白激酶的激酶(MEK)1、MEK2、细胞外信号调节激酶(ERK)1、ERK2 mRNA表达强度.结果:NDGA可抑制HepG2细胞增殖,且呈剂量依赖性;NDGA干预后HepG2细胞中MEK1、MEK2、ERK1、ERK2mRNA的表达强度随着浓度的增加呈递减趋势;不同浓度NDGA干预均显著降低MEK1 mRNA的表达强度(P＜0.05),在NDGA干预浓度为100 μmol/L及200 μmol/L时可显著降低MEK2、ERK1、ERK2 mRNA表达强度(P＜0.05).结论:NDGA可抑制HepG2细胞增殖,其作用机制与抑制MEK/ERK信号通路有关.     

偶氮鎓二醇盐衍生物抑制肝癌细胞增殖的机制

目的通过体内实验与体外实验探究NO供体前药即偶氮鎓二醇盐衍生物PABA/NO对Bel-7402肝癌细胞增殖与凋亡的影响。方法MTT法检测PABA/NO对Bel-7402细胞增殖的影响;蛋白免疫印迹法检测Bel-7402细胞中抗凋亡蛋白Bcl-2和Bcl-x L、促凋亡蛋白Bax和Bad、细胞色素C(Cyt c)、活化胱天蛋白酶9、活化胱天蛋白酶3、活化聚二磷酸腺苷核糖聚合酶(cleaved-PARP)、胞内磷脂酰肌醇激酶(PI3K)、蛋白激酶B(AKT)、哺乳动物雷帕霉素靶蛋白(mTOR)、MAPK/ERK激酶(MEK)和细胞外调节蛋白激酶(ERK)的表达。分别用PI3K抑制剂LY294002、ERK抑制剂U0126和NO清除剂Carboxy-PTIO预处理Bel-7402细胞,检测对上述因子的影响。用健康雄性BALB/c小鼠建立肝癌H22移植瘤小鼠模型,随机分为对照组、PABA/NO低剂量组(1 mg·kg~(-1))、PABA/NO中剂量组(2 mg·kg~(-1))和PABA/NO高剂量组(4 mg·kg~(-1))。将H22细胞悬液接种于小鼠腋下,第2天各组小鼠开始尾静脉注射药物,3 d注射1次,连续14 d。观察各组小鼠肿瘤的生长状况,计算抑瘤率。Western印迹法检测肿瘤组织中CD34,PI3K,AKT,mTOR,MEK和ERK的表达。结果 PABA/NO可以有效抑制Bel-7402细胞的增殖并诱导细胞凋亡,具有一定的浓度依赖性。PABA/NO可下调Bcl-2和Bcl-x L,上调Bax和Bad的表达,并释放Cyt c,激活胱天蛋白酶9和胱天蛋白酶3,诱导细胞凋亡。与此同时,PABA/NO还可以激活PARP,并抑制PI3K/AKT/m TOR和MEK/ERK信号通路在细胞内的表达。LY294002和U0126可以提高PABA/NO诱导Bel-7402细胞凋亡的发生率,而Carboxy-PTIO通过清除NO而明显降低PABA/NO引起的细胞凋亡。另外,PABA/NO还可以明显降低H22荷瘤小鼠的肿瘤体积、肿瘤重量以及CD34在体内的表达而发挥抗肿瘤作用。此外,经PABA/NO处理的小鼠体内PI3K/AKT/m TOR和MEK/ERK信号通路明显被抑制。结论 PABA/NO可以通过抑制PI3K/Akt/mTOR和MEK/ERK通路诱导肝癌细胞凋亡。     

PI3K/Akt信号通路在小檗碱联合人参皂苷Rg3诱导鼻咽癌细胞凋亡中的调控作用

目的研究PI3K/Akt信号通路在小檗碱联合人参皂苷Rg3诱导鼻咽癌细胞凋亡中的作用。方法RTCA法检测小檗碱联合人参皂苷Rg3对鼻咽癌CNE2、6-10B细胞增殖的影响;Hoechst 33342染色法、荧光双染流式细胞仪检测药物对CNE2细胞凋亡的影响;Western blot法检测PI3K/Akt信号通路关键蛋白及凋亡相关蛋白表达的变化。结果小檗碱联合人参皂苷Rg3可抑制鼻咽癌CNE2、6-10B细胞的增殖,诱导CNE2细胞的凋亡。与单独用药组相比,联合用药组细胞的PI3K/Akt信号通路关键蛋白PI3K p110α和p-Akt的表达明显下调(P<0.05)。加入PI3K/Akt信号通路的激活剂SC79后,小檗碱联合人参皂苷Rg3抑制CNE2细胞增殖和诱导细胞凋亡的效应降低,p-Akt、Survivin、PCNA及Bcl-2表达量增加,Bax的表达下降。结论小檗碱联合人参皂苷Rg3可通过PI3K/Akt信号通路发挥抑制鼻咽癌细胞增殖和诱导细胞凋亡的作用。     

人参皂苷Rb1拮抗达沙替尼抑制NK细胞杀伤卵巢癌的研究

目的研究抗癌药达沙替尼对自然杀伤细胞（NK细胞）杀伤卵巢癌细胞的抑制效应,并探讨人参皂苷Rb1拮抗这种免疫抑制效应的作用及其分子机制。方法分别用达沙替尼、人参皂苷Rb1以及达沙替尼联合人参皂苷Rb1预处理NK细胞,未经药物处理的NK细胞设为对照。采用CFSE／PI双染色法,经流式细胞仪检测与NK细胞混合培养的卵巢癌HO-8910细胞的死亡率来明确NK细胞的杀伤功能;采用Annexin V-FITC／PI双染色法测定NK细胞的凋亡率来明确其生存活力;采用real-timePCR法测定NK细胞颗粒酶B的mRNA表达量;采用免疫印迹法检测NK细胞ERK的蛋白水平。结果与对照组相比,达沙替尼处理组的NK细胞对卵巢癌HO-8910细胞的杀伤率显著下降（P〈0．01）,NK细胞的颗粒酶B的mRNA水平和磷酸化ERK（pERK）表达均下调;达沙替尼合并人参皂苷Rb1处理组的NK细胞对卵巢癌HO-8910细胞的杀伤率较达沙替尼组升高（P〈0．05）,而且颗粒酶B的mRNA水平、pERK表达均较达沙替尼组有所恢复;与对照组相比,人参皂苷Rb1单独处理组的NK细胞的生存活力、颗粒酶B水平、pERK表达量以及杀伤功能均无显著差异（P〈0．05）。结论达沙替尼对NK细胞杀伤卵巢癌细胞有抑制效应,可能与下调NK细胞的杀伤介质颗粒酶B和抑制ERK磷酸化有关。人参皂苷Rb1虽然不能直接活化NK细胞,但是能拮抗达沙替尼对NK细胞的上述抑制效应,提示联用人参皂苷Rb1能减少抗癌药物达沙替尼对免疫效应细胞的抑制作用。     

Extracellular taurine induces angiogenesis by activating ERK-, Akt-, and FAK-dependent signal pathways

Taurine, a non essential sulfur-containing amino acid, plays a critical role in cardiovascular functions. We here examined the effect of taurine on angiogenesis and its underlying signal pathway. Taurine treatment increased angiogenesis in vitro and in vivo, which was followed by activation of the phosphatidylinositol 3-kinase (PI3K)/Akt, MEK/ERK, and Src/FAK signaling pathways. Further, taurine promoted endothelial cell cycle progression to the S and G2/M phases by up-regulating the positive cell cycle proteins, particularly cyclins D1 and B, as well as down-regulating the negative cell cycle proteins, p53 and p21(WAF1/CIP1), resulting in Rb phosphorylation. This angiogenic event was inhibited by inhibitors of PI3K and MEK. In addition, a PI3K inhibitor blocked the activation of Akt and ERK, while Akt knockdown did not affect taurine-induced ERK activation, indicating that PI3K is an upstream mediator of both MEK and Akt. Taurine-induced endothelial cell migration was suppressed by Src inhibitor, but not by other inhibitors, suggesting that the increase in cell migration is regulated by Src-dependent pathway. Moreover, inhibition of cellular taurine uptake by β-alanine and taurine transporter knockdown promoted taurine-induced cell proliferation, ERK and Akt activation, and in vivo angiogenesis, suggesting that extracellular taurine induces angiogenesis. However, taurine did not induce vascular inflammation and permeability in vitro and in vivo. These data demonstrate that extracellular taurine promotes angiogenesis by Akt- and ERK-dependent cell cycle progression and Src/FAK-mediated cell migration without inducing vascular inflammation, indicating that it is potential use for the treatment of vascular dysfunction-associated human diseases.     

三萜皂苷Saxifragifolin D抑制人肝癌耐药细胞HepG2/ADM生长并诱导细胞凋亡作用研究

目的研究Saxifragifolin D(SD)对人肝癌耐药细胞HepG2/ADM的生长抑制及诱导凋亡作用。方法采用MTT法观察SD对HepG2/ADM细胞的增殖抑制作用,应用流式细胞仪分析SD对细胞周期的影响,AnnexinⅤ-FITC/PI双染检测凋亡细胞比率,JC-1染色观察SD对细胞内线粒体膜电位的影响,Western blot检测凋亡相关蛋白caspase-9,caspase-3和PARP的激活及c-Raf,MEK和ERK蛋白的表达和磷酸化水平。结果 SD可以明显抑制人肝癌耐药细胞HepG2/ADM的增殖。细胞周期检测发现SD诱导细胞产生亚二倍体凋亡峰,同时细胞凋亡率也由对照组的5.3%增加到34.8%和47.8%。线粒体膜电位检测结果显示SD导致细胞内线粒体膜电位的明显降低。Western blot检测结果表明caspase-9,caspase-3被激活,PARP被剪切活化,cytochrome C由线粒体释放至胞质,c-Raf、MEK和ERK蛋白的磷酸化水平降低。结论 SD可以抑制人肝癌耐药细胞HepG2/ADM增殖并诱导其凋亡,作用机制可能与线粒体功能障碍及抑制c-Raf/MEK/ERK通路的活化有关。     

Low-Dose Radiation Induces Cell Proliferation in Human Embryonic Lung Fibroblasts but not in Lung Cancer Cells: Importance of ERK1/2 and AKT Signaling Pathways

Hormesis and adaptive responses are 2 important biological effects of low-dose ionizing radiation (LDR). In normal tissue, LDR induces hormesis as evinced by increased cell proliferation; however, whether LDR also increases tumor cell proliferation needs to be investigated. In this study, cell proliferation was assayed by total cell numbers and the Cell Counting Kit 8 assay. Mitogen-activated protein kinases (MAPK)/extracellular signal-regulated kinase (ERK) and phosphatidylinositol 3′ -kinase(PI3K)-Akt (PI3K/AKT) phosphorylation were determined by Western blot analysis. Human embryonic lung fibroblast 2BS and lung cancer NCI-H446 cell lines were irradiated with LDR at different doses (20-100 mGy). In response to 20 to 75 mGy X-rays, cell proliferation was significantly increased in 2BS but not in NCI-H446 cells. In 2BS cells, LDR at 20 to 75 mGy also stimulated phosphorylation of MAPK/ERK pathway proteins including ERK, MEK, and Raf and of the PI3K/AKT pathway protein AKT. To test whether ERK1/2 and AKT pathway activation was involved in the stimulation of cell proliferation in 2BS cells, the MAPK/ERK and PI3K/AKT pathways were inhibited using their specific inhibitors, U0126 and {"type":"entrez-nucleotide","attrs":{"text":"LY294002","term_id":"1257998346","term_text":"LY294002"}}LY294002. U0126 decreased the phosphorylation of ERK1/2, and {"type":"entrez-nucleotide","attrs":{"text":"LY294002","term_id":"1257998346","term_text":"LY294002"}}LY294002 decreased the phosphorylation of AKT; each could significantly inhibit LDR-induced 2BS cell proliferation. However, LDR did not stimulate these kinases, and kinase inhibitors also did not affect cell proliferation in the NCI-H446 cells. These results suggest that LDR stimulates cell proliferation via the activation of both MAPK/ERK and PI3K/AKT signaling pathways in 2BS but not in NCI-H446 cells. This finding implies the potential for applying LDR to protect normal tissues from radiotherapy without diminishing the efficacy of tumor therapy.     

The RAS/RAF/MEK/ERK and the PI3K/AKT signalling pathways: role in cancer pathogenesis and implications for therapeutic approaches

INTRODUCTION: The RAS/RAF/MAP kinase-ERK kinase (MEK)/extracellular-signal-regulated kinase (ERK) (MAPK) and the PI3K/AKT/mammalian target of rapamycin (mTOR) (PI3K) pathways are frequently deregulated in human cancer as a result of genetic alterations in their components or upstream activation of cell-surface receptors. These signalling cascades are regulated by complex feedback and cross-talk mechanisms. AREAS COVERED: In this review the key components of the MAPK and AKT pathways and their molecular alterations are described. The complex interactions between these signalling cascades are also analysed. EXPERT OPINION: The observation that the MAPK and the PI3K pathways are often deregulated in human cancer makes the components of these signalling cascades interesting targets for therapeutic intervention. Recently, the presence of compensatory loops that activate one pathway following the blockade of the other signalling cascade has been demonstrated. Therefore, the blockade of both pathways with combinations of signalling inhibitors might result in a more efficient anti-tumor effect as compared with a single agent. In addition, the MAPK and PI3K pathways are activated by mutations that coexist or can be mutually exclusive. In this regard, a large-scale characterization of the cancer genome might offer personalized cancer genomic information, which may improve the anti-tumor efficacy of signalling inhibitors.     

Recent advances of MEK inhibitors and their clinical progress

The RAS/RAF/MEK/ERK signaling pathway has been a major clinical focus in oncology research in recent years. A clearer association of B-RAF mutations to cancers such as melanoma, papillary thyroid cancer and others has brought an increasing interest in chemotherapeutics that target this cellular signaling pathway. In this review, the authors summarize the current understanding of science and therapeutic use of the MEK inhibitors targeting the RAS/RAF/ MEK/ERK pathway. Clinical progresses of PD0325901 and AZD6244 are highlighted in addition to developments of new MEK inhibitors. Recently disclosed MEK inhibitors in two sub-divided classes, ATP noncompetitive and ATP competitive inhibitors are discussed.     

Rotenone restrains the proliferation,motility and epithelial–mesenchymal transition of colon cancer cells and the tumourigenesis in nude mice via PI3K/AKT pathway

Rotenone, a toxic rotenoid compound, has anti-tumour effects on several cancers. This study aims to clarify the effect of rotenone on the proliferation, apoptosis, invasion and migration of colon cancer cells and tumourigenesis in nude mice. The present results show that rotenone significantly inhibited the proliferation, promoted the apoptosis, and suppressed the invasion and migration of colon cancer cells in a dose-dependent manner. Rotenone inhibited PI3K/AKT pathway in LoVo and SW480 cells in a dose-dependent manner. In addition, rotenone regulated the proliferation, apoptosis, invasion, migration and EMT of LoVo and SW480 cells through PI3K/AKT pathway. In colon cancer xenograft mice, rotenone inhibited tumour volume and weight in nude mice, inhibited PI3K/AKT pathway and EMT in vivo. Therefore, rotenone inhibited the proliferation, invasion and migration, promoted the apoptosis of colon cancer cells through PI3K/AKT pathway in vitro, and suppressed the tumourigenesis in nude mice in vivo.     

Sorafenib (BAY 43-9006) in hepatocellular carcinoma patients: from discovery to clinical development

Angiogenesis and signaling through the RAS/RAF/mitogen-activated protein/extracellular signal-regulated kinase (ERK) kinase (MEK)/ERK cascade have been reported to play important roles in the development of hepatocellular carcinoma (HCC). Sorafenib (Nexavar), a novel bi-aryl urea BAY 43-9006, is an orally administered multikinase inhibitor with activity against RAS/RAF kinases multikinase inhibitor with activity against RAF kinases and several receptor tyrosine kinases, including vascular endothelial growth factor receptor (VEGFR), platelet-derived growth factor receptor (PDGFR), FLT3, Ret, and c-Kit. It is involved in angiogenic pathway and cell proliferation. Sorafenib has demonstrated potent anti-tumor activity in in vitro studies, preclinical xenograft models of different tumor types and human clinical trials. This review summarizes the history of sorafenib from its discovery by the medicinal chemistry approach through to clinical development and ongoing trials on the combination between sorafenib and trans-arterial chemoembolization (TACE) in HCC patients.     

Intracellular signaling pathways involved in the relaxin-induced proliferation of rat Sertoli cells

Regulation of Sertoli cell number is a key event to determine normal spermatogenesis. We have previously shown that relaxin and its G-protein coupled receptor RXFP1 are expressed in rat Sertoli cells, and that relaxin stimulates Sertoli cell proliferation. This study examined the mechanisms underlying the mitogenic effect of relaxin in a primary culture of Sertoli cells removed from testes of immature rats. Stimulation with exogenous relaxin increased Sertoli cell number and the expression of the proliferating cell nuclear antigen (PCNA), but did not affect the mRNA level of the differentiation markers cadherins 1 and 2. Relaxin-induced Sertoli cell proliferation was blocked by inhibition of MEK/ERK1/2 or PI3K/AKT pathways, but not by inhibition of PKC or EGFR activity. Relaxin induced a rapid and transient activation of ERK1/2 phosphorylation, which was MEK and SRC-dependent, and involved upstream activation of G(i). AKT activation could be detected 5min after relaxin stimulation, and was still detected after 24h of stimulation with relaxin. Relaxin-induced AKT phosphorylation was G(i)- but not PKA-dependent, and it was blocked by both PI3K and MEK inhibitors. In conclusion, the mitogenic effect of relaxin in Sertoli cell involves coupling to G(i) and activation of both MEK/ERK1/2 and PI3K/AKT pathways.     

Water extract of Korean red ginseng stimulates angiogenesis by activating the PI3K/Akt-dependent ERK1/2 and eNOS pathways in human umbilical vein endothelial cells

Angiogenesis is important for promoting cardiovascular disease, wound healing, and tissue regeneration. We investigated the effects of Korean red ginseng water extract (KRGE) on angiogenesis and its underlying signal mechanism. KRGE increased in vitro proliferation, migration, and tube formation of human umbilical vein endothelial cells, as well as stimulated in vivo angiogenesis without increasing VEGF expression. KRGE-induced angiogenesis was accompanied by phosphorylation of ERK1/2, phosphatidylinositol 3-kinase (Akt), and endothelial nitric oxide synthase (eNOS) as well as an increase in NO production. Inhibition of PI3K activity by wortmannin completely inhibited KRGE-induced angiogenesis and phosphorylation of Akt, ERK1/2, and eNOS, indicating that PI3K/Akt activation is an upstream event of the KRGE-mediated angiogenic pathway. The MEK inhibitor PD98059 blocked KRGE-induced ERK1/2 phosphorylation without affecting Akt and eNOS activation. However, the eNOS inhibitor N(G)-monomethyl-L-arginine effectively inhibited tube formation, but partially blocked proliferation and migration as well as ERK phosphorylation, without altering Akt and eNOS activation, revealing that the eNOS/NO pathway is partially involved in ERK1/2 activation. This study demonstrated that KRGE stimulates in vitro and in vivo angiogenesis through the activation of the PI3K/Akt-dependent ERK1/2 and eNOS signal pathways and their cross talk.     

Ultrasound stimulates cyclooxygenase-2 expression and increases bone formation through integrin, focal adhesion kinase, phosphatidylinositol 3-kinase, and Akt pathway in osteoblasts

It has been shown that ultrasound (US) stimulation accelerates fracture healing in animal models and in clinical studies. Here we found that US stimulation transiently increased the surface expression of alpha2, alpha5, beta1, and beta3 integrins in cultured osteoblasts, as shown by flow cytometric analysis and immunofluorescence staining. US stimulation increased prostaglandin E(2) formation and the protein and mRNA levels of cyclooxygenase-2 (COX-2). At the mechanistic level, anti-integrin alpha5beta1 and alphavbeta3 antibodies or rhodostomin, a snake venom disintegrin, attenuated the US-induced COX-2 expression. Phosphatidylinositol 3-kinase (PI3K) inhibitors 2-(4-morpholinyl)-8-phenyl-1(4H)-benzopyran-4-one hydrochloride (LY294002) and wortmannin also inhibited the potentiating action of US. US stimulation increased the phosphorylation of focal adhesion kinase (FAK), extracellular signal-regulated kinases (ERK), p85 subunit of PI3K, and serine 473 of Akt. COX-2 promoter activity was enhanced by US stimulation in cells transfected with pCOX2-Luc. Cotransfection with dominant-negative mutant of FAK(Y397F), p85(Deltap85), Akt(K179A), or ERK2(K52R) inhibited the potentiating action of US on COX-2 promoter activity. Expression of mineralized nodule was lower in dominant-negative mutants of FAK, p85, and Akt-transfected clones than in vector-transfected control cells. Taken together, our results provide evidence that US stimulation increases COX-2 expression and promotes bone formation in osteoblasts via the integrin/FAK/PI3K/Akt and ERK signaling pathway.