摘要
目的研究鞘氨醇激酶1(SphK1)和黏着斑激酶(FAK)在结肠癌中的表达及其与临床病理特征的关系,并探讨其在结肠癌发生发展中的作用及其可能的分子机制。
方法①采用免疫组织化学SP法检测66例结肠癌、对应癌旁及正常结肠黏膜组织中SphK1和FAK的表达;用统计学方法分析二者表达与临床病理特征的关系。②体外培养人结肠癌细胞株lovo,用终浓度为100nmol/L的佛波醇-12-豆蔻酸酯-13-乙酸酯(PMA)以及终浓度为50μmol/L的N,N-二甲基鞘胺醇(DMS)分别作用于人结肠癌lovo细胞,一定时间后,采用MTT法和克隆形成实验检测细胞的增殖能力,Tranwell小室模型观察细胞迁移和侵袭能力的变化,RT-PCR检测FAKmRNA的表达,Western blot检测FAK蛋白的表达。
结果①组织免疫组化结果显示:Sphk1和FAK蛋白在结肠癌及其癌旁、正常组织中的表达阳性率分别为:72.7%(48/66)、51.5.%(34/66)、34.8%(23/66);77.3%(51/66)、37.9%(25/66)、22.7%(15/66),Sphk1和FAK在结肠癌与癌旁及正常结肠黏膜组织的阳性率差异均有统计学意义(P值<0.05)。SphK1和FAK表达之间存在明显关联性(r=0.480,P=0.000)。SphK1和FAK在癌组织中的表达水平均与肿瘤浸润程度、组织分化程度、有无远处转移、淋巴结转移、临床分期有关(P值均<0.05)。②体外实验结果显示:PMA显著促进细胞的增殖、迁移和侵袭能力,DMS则显著抑制细胞的增殖、迁移和侵袭能力(对照组、PMA组和DMS组的细胞增殖活力分别为:0.71±0.03vs1.05±0.05vs0.46±0.04;克隆形成率分别为:1.32%±0.26%vs2.17%±0.17%vs0.73%±0.13%;迁移细胞数分别为:72.19±3.36vs98.46±6.25vs40.48±4.27;侵袭细胞数分别为:75.48±4.12vs143.36±5.73vs38.57±3.24;P值均<0.05vs对照组)。PMA显著促进黏着斑激酶(FAK)的活性和表达,相反DMS则抑制FAK的活性和表达(对照组、PMA组和DMS组FAK mRNA的表达强度:0.151±0.008vs0.212±0.014vs0.114±0.021;蛋白:0.332±0.022vs0.374±0.029vs0.296±0.018;磷酸化FAK(p-FAK Tyr397)蛋白:0.186±0.032vs0.234±0.017vs0.112±0.023;P值均<0.05vs对照组)。
结论1.SphKl和FAK可能与结肠癌的发生、发展密切相关,并可能在结肠癌的浸润和转移中起重要作用。
2. SphK1可促进lovo细胞的增殖、侵袭和迁移能力,其机制可能是通过激活FAK通路而发挥作用。
Objective To study the expression of sphingosine kinase1(SphK1) and Focal Adhesion Kinase (FAK) in colon carcinoma tissues and to explore their correlation with clinicopathological features. Then further investigate their relationship with the cell adhesion, migration and invasion of human colon cancer cell line lovo and its associated mechanism through vitro examination.
Methods①Sixty-six paraffin-embedded colon carcinoma samples were tested with immunohistochemistry method, stactistical analysis was then carried out to explore their expression in clinicopathological features.②Cultured lovo cells were divided into three groups:PMA group, DMS group and control group. Cells of PMA group were treated with100nmol/L Phorbol12-myristate13-acetate (PMA), the DMS group was treated with50μmol/L N, N-dimethylsphingosine (DMS), while the control group was treated with equal volume of culture medium. After treatment, cell proliferation was detected by MTT assay and colony formation assay, the migration and invasion capability of the cells were assessed in Transwell chambers. RT-PCR and Western blot were used to evaluate the mRNA and protein expression of FAK.
Results①The immunohistochemistry results show:the positive rates of SphKl and FAK in66colon carcinoma samples were72.7%(48/66) and77.3%(51/66), which were higher than those in adjacent tissues[SphK1:51.5%(34/66); FAK37.9%(25/66)] and normal mucosa[SphK1:34.8%(23/66); FAK:22.7%(15/66)], showing a significant statistical difference(P<0.05). There was a close correlation between SphKl and FAK expression levels (r=0.480, P=0.000). Overexpression of SphKl and FAK in colon carcinoma were all related with depth of invasion, differentiation, distant and lymph node metastasis and Dukes'stages (P<0.05).②Vitro tests'results show that PMA significantly enhanced cells proliferation, invasion and migration, whereas DMS suppressed cells proliferation, migration and invasion (the cells viability, cloning rate, migration and invasion cell count of control group, PMA group and DMS group were as follow:cells viability:0.71±0.03vs1.05±0.05vs0.46±0.04; cloning rate:1.32%±0.26%vs2.17%±0.17%vs0.73%±0.13%; migration cell count:72.19±3.36vs98.46±6.25vs40.48±4.27; invasion cell count:75.48±4.12vs143.36±5.73vs38.57±3.24; all P<0.05vs control group). PMA significantly up-regulated the expression and activity of focal adhesion kinase (FAK), while DMS down-regulated the expression and activity of FAK (FAK mRNA:0.151±0.008vs0.212±0.014vs0.114±0.021; FAK protein:0.332±0.022vs0.374±0.029vs0.296±0.018; phosphor-FAK protein:0.186±0.032vs0.234±0.017vs0.112±0.023; P<0.05vs control group).
Conclusions1. Overexpression of SphK1and NF-κB may be involved in the occurrence and development of colon carcinoma. Moreover, SphKl and NF-κB may be correlated with the invasion and metastasis of colon carcinoma.
2. SphKl enhances cell proliferation, migration and invasion in human colon cancer cell line lovo possibly by activating FAK.
引文
[1]游伟程.常见恶性肿瘤的流行情况[J].中华医学信息导报,2005,20(22):22.
[2]Weitz J, Koch M, Debus J, et al. Colorectal cancer[J]. Lancet,2005,365(9454): 153-165.
[3]Le Scolan E, Pchejetski D, Banno Y, et al. Overexpression of sphingosine kinase 1 is an oncogenic event in erythroleukemic progression[J]. Blood,2005,106(5): 1808-1816.
[4]Xia P, Gamble J R, Wang L, et al. An oncogenic role of sphingosine kinase[J]. Curr Biol,2000,10(23):1527-1530.
[5]Lebman D A, Spiegel S. Cross-talk at the crossroads of sphingosine-1-phosphate, growth factors, and cytokine signaling[J]. J Lipid Res,2008,49(7):1388-1394.
[6]Spiegel S, Milstien S. Functions of the multifaceted family of sphingosine kinases and some close relatives[J]. J Biol Chem,2007,282(4):2125-2129.
[7]Taha T A, Hannun Y A, Obeid L M. Sphingosine kinase:biochemical and cellular regulation and role in disease[J]. J Biochem Mol Biol,2006,39 (2):113-131.
[8]Bao M, Chen Z, Xu Y, et al. Sphingosine kinase 1 promotes tumour cell migration and invasion via the S1P/EDG1 axis in hepatocellular carcinoma[J]. Liver Int,2012,32(2):331-338.
[9]Meng H, Yuan Y, Lee V M. Loss of Sphingosine kinase 1/S1P signaling impairs cell growth and survival of neurons and progenitor cells in the developing sensory ganglia[J]. PLoS One,2011,6(11):e27150.
[10]Hanks S K, Calalb M B, Harper M C, et al. Focal adhesion protein-tyrosine kinase phosphorylated in response to cell attachment to fibronectin[J]. Proc Natl Acad Sci U S A,1992,89(18):8487-8491.
[11]Schaller M D, Borgman C A, Cobb B S, et al. pp125FAK a structurally distinctive protein-tyrosine kinase associated with focal adhesions[J]. Proc Natl Acad Sci U S A,1992,89(11):5192-5196.
[12]Cance W G, Harris J E, Iacocca M V, et al. Immunohistochemical analyses of focal adhesion kinase expression in benign and malignant human breast and colon tissues:correlation with preinvasive and invasive phenotypes[J]. Clin Cancer Res,2000,6(6):2417-2423.
[13]Ilic D, Furuta Y, Kanazawa S, et al. Reduced cell motility and enhanced focal adhesion contact formation in cells from FAK-deficient mice[J]. Nature,1995, 377(6549):539-544.
[14]An J Y, Zhang X L, Yao D M, et al. [The influence of down-regulation of focal adhesion kinase by RNA interference on the adhesion and migration of rat hepatic stellate cells in vitro][J]. Zhonghua Gan Zang Bing Za Zhi,2009,17(7): 509-514.
[15]Dasari V R, Kaur K, Velpula K K, et al. Downregulation of Focal Adhesion Kinase (FAK) by cord blood stem cells inhibits angiogenesis in glioblastoma[J]. Aging (Albany NY),2010,2(11):791-803.
[16]Gerthoffer W T. Mechanisms of vascular smooth muscle cell migration [J]. Circ Res,2007,100(5):607-621.
[17]Dotan E, Cohen S J, Alpaugh K R, et al. Circulating tumor cells:evolving evidence and future challenges [J]. Oncologist,2009,14(11):1070-1082.
[18]Hellmig S, Troch K, Ott S J, et al. Role of Helicobacter pylori Infection in the treatment and outcome of chronic urticaria[J]. Helicobacter,2008,13(5):341-345.
[19]Einicker-Lamas M, Wenceslau L D, Bernardo R R, et al. Sphingosine-1-phosphate formation activates phosphatidylinositol-4 kinase in basolateral membranes from kidney cells:crosstalk in cell signaling through sphingolipids and phospholipids[J]. J Biochem,2003,134(4):529-536.
[20]Takabe K, Paugh S W, Milstien S, et al. "Inside-out" signaling of sphingosine-1 phosphate:therapeutic targets[J]. Pharmacol Rev,2008,60(2):181-195.
[21]Kim R H, Takabe K, Milstien S, et al. Export and functions of sphingosine-1-phosphate[J]. Biochim Biophys Acta,2009,1791(7):692-696.
[22]Alvarez S E, Milstien S, Spiegel S. Autocrine and paracrine roles of sphingosine-1-phosphate[J]. Trends Endocrinol Metab,2007,18(8):300-307.
[23]Schwab S R, Cyster J G. Finding a way out:lymphocyte egress from lymphoid organs[J]. Nat Immunol,2007,8(12):1295-1301.
[24]Hannun Y A, Obeid L M. Principles of bioactive lipid signalling:lessons from sphingolipids[J]. Nat Rev Mol Cell Biol,2008,9(2):139-150.
[25]Shida D, Takabe K, Kapitonov D, et al. Targeting SphK1 as a new strategy against cancer[J]. Curr Drug Targets,2008,9(8):662-673.
[26]Cuvillier O. Sphingosine kinase-1--a potential therapeutic target in cancer[J]. Anticancer Drugs,2007,18(2):105-110.
[27]Shida D, Fang X, Kordula T, et al. Cross-talk between LPA1 and epidermal growth factor receptors mediates up-regulation of sphingosine kinase 1 to promote gastric cancer cell motility and invasion[J]. Cancer Res,2008,68(16):6569-6577.
[28]Schaller M D, Borgman C A, Cobb B S, et al. pp125FAK a structurally distinc-tive protein-tyrosine kinase associated with focal adhesions[J]. Proc Natl Acad Sci U S A,1992,89(11):5192-5196.
[29]Cary L A, Chang J F, Guan J L. Stimulation of cell migration by overexpression of focal adhesion kinase and its association with Src and Fyn[J]. J Cell Sci,1996,109 (Pt 7):1787-1794.
[30]Kornberg L, Earp H S, Parsons J T, et al. Cell adhesion or integrin clustering increases phosphorylation of a focal adhesion-associated tyrosine kinase[J]. J Biol Chem,1992,267(33):23439-23442.
[31]Lipfert L, Haimovich B, Schaller M D, et al. Integrin-dependent phosphorylation and activation of the protein tyrosine kinase pp125FAK in platelets [J]. J Cell Biol,1992,119(4):905-912.
[32]Schlaepfer D D, Hanks S K, Hunter T, et al. Integrin-mediated signal transduc-tion linked to Ras pathway by GRB2 binding to focal adhesion kinase[J]. Nature,1994,372(6508):786-791.
[33]Guan J L. Role of focal adhesion kinase in integrin signaling[J]. Int J Biochem Cell Biol,1997,29(8-9):1085-1096.
[34]Xu L H, Owens L V, Sturge G C, et al. Attenuation of the expression of the focal adhesion kinase induces apoptosis in tumor cells[J]. Cell Growth Differ,1996,7 (4):413-418.
[35]Hungerford J E, Compton M T, Matter M L, et al. Inhibition of pp125FAK in cultured fibroblasts results in apoptosis[J]. J Cell Biol,1996,135(5):1383-1390.
[36]Weiner T M, Liu E T, Craven R J, et al. Expression of focal adhesion kinase gene and invasive cancer[J]. Lancet,1993,342(8878):1024-1025.
[37]Owens L V, Xu L, Craven R J, et al. Overexpression of the focal adhesion kinase (p125FAK) in invasive human tumors[J]. Cancer Res,1995,55(13):2752-2755.
[38]Owens L V, Xu L, Dent G A, et al. Focal adhesion kinase as a marker of invasive potential in differentiated human thyroid cancer[J]. Ann Surg Oncol,1996,3(1): 100-105.
[39]Gerthoffer W T. Mechanisms of vascular smooth muscle cell migration[J]. Circ Res,2007,100(5):607-621.
[40]Dasari V R, Kaur K, Velpula K K, et al. Downregulation of Focal Adhesion Kinase (FAK) by cord blood stem cells inhibits angiogenesis in glioblastoma[J]. Aging (Albany NY),2010,2(11):791-803.
[41]An J Y, Zhang X L, Yao D M, et al. [The influence of down-regulation of focal adhesion kinase by RNA interference on the adhesion and migration of rat hepatic stellate cells in vitro][J]. Zhonghua Gan Zang Bing Za Zhi,2009,17(7):509-514.
[42]Trusolino L, Serini G, Cecchini G, et al. Growth factor-dependent activation of alphavbeta3 integrin in normal epithelial cells:implications for tumor invasion[J]. J Cell Biol,1998,142(4):1145-1156.
[43]Schmidt R, Streit M, Kaiser R, et al. De novo expression of the alpha5betal-fibronectin receptor in HT29 colon-cancer cells reduces activity of C-SRC. Increase of C-SRC activity by attachment on fibronectin[J]. Int J Cancer,1998, 76(1):91-98.
[44]Kawamori T, Osta W, Johnson K R, et al. Sphingosine kinase 1 is up-regulated in colon carcinogenesis[J]. FASEB J,2006,20(2):386-388.
[45]Kawamori T, Kaneshiro T, Okumura M, et al. Role for sphingosine kinase 1 in colon carcinogenesis[J]. FASEB J,2009,23(2):405-414.
[46]凌霄华,于欣,汪丽燕,等.黏着斑激酶在结直肠癌中的表达与侵袭、转移的相关性研究[J].哈尔滨医科大学学报,2008,42(1):47-49.
[47]Li W, Yu C P, Xia J T, et al. Sphingosine kinase 1 is associated with gastric cancer progression and poor survival of patients [J]. Clin Cancer Res,2009,15 (4):1393-1399.
[48]Hengst J A, Guilford J M, Conroy E J, et al. Enhancement of sphingosine kinase 1 catalytic activity by deletion of 21 amino acids from the COOH-terminus[J]. Arch Biochem Biophys,2010,494(1):23-31.
[49]Xia P, Wang L, Gamble J R, et al. Activation of sphingosine kinase by tumor necrosis factor-alpha inhibits apoptosis in human endothelial cells[J]. J Biol Chem,1999,274(48):34499-34505.
[50]Cai X, Lietha D, Ceccarelli D F, et al. Spatial and temporal regulation of focal adhesion kinase activity in living cells[J]. Mol Cell Biol,2008,28(1):201-214.
[51]Fu Y M, Zhang H, Ding M, et al. Specific amino acid restriction inhibits attachment and spreading of human melanoma via modulation of the integrin/ focal adhesion kinase pathway and actin cytoskeleton remodeling[J]. Clin Exp Metastasis,2004,21(7):587-598.
[52]Margadant C, van Opstal A, Boonstra J. Focal adhesion signaling and actin stress fibers are dispensable for progression through the ongoing cell cycle [J]. J Cell Sci,2007,120(Pt 1):66-76.
[53]Huang D, Khoe M, Befekadu M, et al. Focal adhesion kinase mediates cell survival via NF-kappaB and ERK signaling pathways[J]. Am J Physiol Cell Physiol,2007,292(4):C1339-C1352.
[54]余红梅,李琪,尤列·皮尔曼,等.鞘氨醇激酶1对肿瘤坏死因子α诱导的气道黏蛋白5AC的调节作用[J].中华医学杂志,2011,91(6):391-395.
[55]Bergelin N, Blom T, Heikkila J, et al. Sphingosine kinase as an oncogene: autocrine sphingosine 1-phosphate modulates ML-1 thyroid carcinoma cell migration by a mechanism dependent on protein kinase C-alpha and ERK1/2[J]. Endocrinology,2009,150(5):2055-2063.
[56]钟月圆,黄杰安,刘诗权,等.Sphkl对人结肠癌细胞株Lovo增殖与侵袭的影响及其作用机制[J].世界华人消化杂志,2010(24):2528-2532.
[57]钟月圆,刘诗权,黄杰安,等.鞘氨醇激酶-1激活ERK通路介导人结肠癌细胞株LoVo侵袭与迁移的实验[J].肿瘤防治研究,2011,38(8):861-865.
[1]Olivera A, Kohama T, Tu Z, et al. Purification and characterization of rat kidney sphingosine kinase[J]. J Biol Chem,1998,273(20):12576-12583.
[2]Kohama T, Olivera A, Edsall L, et al. Molecular cloning and functional characterization of murine sphingosine kinase[J]. J Biol Chem,1998,273(37): 23722-23728.
[3]Liu H, Sugiura M, Nava V E, et al. Molecular cloning and functional characterization of a novel mammalian sphingosine kinase type 2 isoform[J]. J Biol Chem,2000,275(26):19513-19520.
[4]Murate T, Banno Y, T-Koizumi K, et al. Cell type-specific localization of sphingosine kinase la in human tissues[J]. J Histochem Cytochem,2001,49 (7): 845-855.
[5]Hait N C, Oskeritzian C A, Paugh S W, et al. Sphingosine kinases, sphingosine 1-phosphate, apoptosis and diseases [J]. Biochim Biophys Acta,2006,1758(12): 2016-2026.
[6]Xia P, Gamble J R, Wang L, et al. An oncogenic role of sphingosine kinase[J]. Curr Biol,2000,10(23):1527-1530.
[7]Bergelin N, Blom T, Heikkila J, et al. Sphingosine kinase as an oncogene: autocrine sphingosine 1-phosphate modulates ML-1 thyroid carcinoma cell migration by a mechanism dependent on protein kinase C-alpha and ERK1/2 [J]. Endocrinology,2009,150(5):2055-2063.
[8]Spiegel S, Milstien S. Sphingosine-1-phosphate:an enigmatic signalling lipid[J]. Nat Rev Mol Cell Biol,2003,4(5):397-407.
[9]Okazaki H, Ishizaka N, Sakurai T, et al. Molecular cloning of a novel putative G protein-coupled receptor expressed in the cardiovascular system[J]. Biochem Biophys Res Commun,1993,190(3):1104-1109.
[10]Maclennan A J, Browe C S, Gaskin A A, et al. Cloning and characterization of a putative G-protein coupled receptor potentially involved in development[J]. Mol Cell Neurosci,1994,5(3):201-209.
[11]Graler M H, Bernhardt G, Lipp M. EDG6, a novel G-protein-coupled receptor related to receptors for bioactive lysophospholipids, is specifically expressed in lymphoid tissue[J]. Genomics,1998,53(2):164-169.
[12]Yamazaki Y, Kon J, Sato K, et al. Edg-6 as a putative sphingosine 1-phosphate receptor coupling to Ca(2+) signaling pathway [J]. Biochem Biophys Res Commun,2000,268(2):583-589.
[13]Im D S, Heise C E, Ancellin N, et al. Characterization of a novel sphingosine 1-phosphate receptor, Edg-8[J]. J Biol Chem,2000,275(19):14281-14286.
[14]Glickman M, Malek R L, Kwitek-Black A E, et al. Molecular cloning, tissue-specific expression, and chromosomal localization of a novel nerve growth factor-regulated G-protein-coupled receptor, nrg-1[J].Mol Cell Neurosci, 1999,14(2):141-152.
[15]Pyne S, Lee S C, Long J, et al. Role of sphingosine kinases and lipid phosphate phosphatases in regulating spatial sphingosine 1-phosphate signalling in health and disease[J]. Cell Signal,2009,21(1):14-21.
[16]Garcia J G, Liu F, Verin A D, et al. Sphingosine 1-phosphate promotes endothelial cell barrier integrity by Edg-dependent cytoskeletal rearrangement [J]. J Clin Invest,2001,108(5):689-701.
[17]Liu Y, Wada R, Yamashita T, et al. Edg-1, the G protein-coupled receptor for sphingosine-1-phosphate, is essential for vascular maturation[J]. J Clin Invest, 2000,106(8):951-961.
[18]Chae S S, Paik J H, Furneaux H, et al. Requirement for sphingosine 1-phosphate receptor-1 in tumor angiogenesis demonstrated by in vivo RNA interference [J]. J Clin Invest,2004,114(8):1082-1089.
[19]Sanchez T, Skoura A, Wu M T, et al. Induction of vascular permeability by the sphingosine-1-phosphate receptor-2 (S1P2R) and its downstream effectors ROCK and PTEN[J]. Arterioscler Thromb Vasc Biol,2007,27(6):1312-1318.
[20]Du W, Takuwa N, Yoshioka K, et al. S1P(2), the G protein-coupled receptor for sphingosine-1-phosphate, negatively regulates tumor angiogenesis and tumor growth in vivo in mice[J]. Cancer Res,2010,70(2):772-781.
[21]Murakami A, Takasugi H, Ohnuma S, et al. Sphingosine 1-phosphate (SIP) regulates vascular contraction via S1P3 receptor:investigation based on a new S1P3 receptor antagonist [J]. Mol Pharmacol,2010,77(4):704-713.
[22]Milstien S, Spiegel S. Targeting sphingosine-1-phosphate:a novel avenue for cancer therapeutics[J]. Cancer Cell,2006,9(3):148-150.
[23]Murph M, Tanaka T, Liu S, et al. Of spiders and crabs:the emergence of lysophospholipids and their metabolic pathways as targets for therapy in cancer [J]. Clin Cancer Res,2006,12(22):6598-6602.
[24]Mizugishi K, Yamashita T, Olivera A, et al. Essential role for sphingosine kinases in neural and vascular development[J]. Mol Cell Biol,2005,25(24): 11113-11121.
[25]Ader I, Brizuela L, Bouquerel P, et al. Sphingosine kinase 1:a new modulator of hypoxia inducible factor lalpha during hypoxia in human cancer cells [J]. Cancer Res,2008,68(20):8635-8642.
[26]Yun J K, Kester M. Regulatory role of sphingomyelin metabolites in hypoxia-induced vascular smooth muscle cell proliferation[J]. Arch Biochem Biophys,2002,408(1):78-86.
[27]Gault C R, Obeid L M. Still benched on its way to the bedside:sphingosine kinase 1 as an emerging target in cancer chemotherapy[J]. Crit Rev Biochem Mol Biol,2011,46(4):342-351.
[28]Jung C G, Kim H J, Miron V E, et al. Functional consequences of SIP receptor modulation in rat oligodendroglial lineage cells[J]. Glia,2007,55(16):1656-1667.
[29]Venkataraman K, Lee Y M, Michaud J, et al. Vascular endothelium as a contributor of plasma sphingosine 1-phosphate[J]. Circ Res,2008,102(6):669-676.
[30]Balthasar S, Bergelin N, Lof C, et al. Interactions between sphingosine-1-phosphate and vascular endothelial growth factor signalling in ML-1 follicular thyroid carcinoma cells[J]. Endocr Relat Cancer,2008,15(2):521-534.
[31]Lee O H, Kim Y M, Lee Y M, et al. Sphingosine 1-phosphate induces angiogenesis:its angiogenic action and signaling mechanism in human umbilical vein endothelial cells[J]. Biochem Biophys Res Commun,1999,264 (3):743-750.
[32]Lee M J, Van Brocklyn J R, Thangada S, et al. Sphingosine-1-phosphate as a ligand for the G protein-coupled receptor EDG-1[J]. Science,1998,279(5356): 1552-1555.
[33]Tan W, Palmby T R, Gavard J, et al. An essential role for Rac1 in endothelial cell function and vascular development[J]. FASEB J,2008,22(6):1829-1838.
[34]Takuwa Y, Du W, Qi X, et al. Roles of sphingosine-1-phosphate signaling in angiogenesis[J]. World J Biol Chem,2010,1(10):298-306.
[35]Dyatlovitskaya E V, Kandyba A G. Sphingolipids in tumor metastases and angiogenesis [J]. Biochemistry (Mosc),2006,71(4):347-353.
[36]Rikitake Y, Hirata K, Kawashima S, et al. Involvement of endothelial nitric oxide in sphingosine-1-phosphate-induced angiogenesis[J].Arterioscler Thromb Vasc Biol,2002,22(1):108-114.
[37]Shida D, Takabe K, Kapitonov D, et al. Targeting SphK1 as a new strategy against cancer[J]. Curr Drug Targets,2008,9(8):662-673.
[38]Caballero S, Swaney J, Moreno K, et al. Anti-sphingosine-1-phosphate monoclonal antibodies inhibit angiogenesis and sub-retinal fibrosis in a murine model of laser-induced choroidal neovascularization[J]. Exp Eye Res,2009,88 (3):367-377.
[39]Sun X, Shikata Y, Wang L, et al. Enhanced interaction between focal adhesion and adherens junction proteins:involvement in sphingosine 1-phosphate-induced endothelial barrier enhancement [J]. Microvasc Res,2009,77(3):304-313.
[40]Camerer E, Regard J B, Cornelissen I, et al. Sphingosine-1-phosphate in the plasma compartment regulates basal and inflammation-induced vascular leak in mice[J]. J Clin Invest,2009,119(7):1871-1879.
[41]Hess A R, Seftor E A, Gruman L M, et al. VE-cadherin regulates EphA2 in aggressive melanoma cells through a novel signaling pathway:implications for vasculogenic mimicry [J]. Cancer Biol Ther,2006,5(2):228-233.
[42]Kapitonov D, Allegood J C, Mitchell C, et al. Targeting sphingosine kinase 1 inhibits Akt signaling, induces apoptosis, and suppresses growth of human glioblastoma cells and xenografts[J]. Cancer Res,2009,69(17):6915-6923.
[43]Sun H Y, Wei S P, Xu R C, et al. Sphingosine-1-phosphate induces human endothelial VEGF and MMP-2 production via transcription factor ZNF580: novel insights into angiogenesis [J]. Biochem Biophys Res Commun,2010,395 (3):361-366.
[44]Morii T, Weissbach L. Sphingosine 1-phosphate and cell migration:resistance to angiogenesis inhibitors [J]. Biochem Biophys Res Commun,2003,310(3):884- 888.
[45]Lamontagne K, Littlewood-Evans A, Schnell C, et al. Antagonism of sphingosine-1- phosphate receptors by FTY720 inhibits angiogenesis and tumor vascularization[J]. Cancer Res,2006,66(1):221-231.
[46]Roberts L R, Gores G J. Hepatocellular carcinoma:molecular pathways and new therapeutic targets [J]. Semin Liver Dis,2005,25(2):212-225.
[47]Visentin B, Vekich J A, Sibbald B J, et al. Validation of an anti- sphingosine-1-phosphate antibody as a potential therapeutic in reducing growth, invasion, and angiogenesis in multiple tumor lineages[J]. Cancer Cell,2006,9(3):225-238.