高振軍 孔慶云 吳愷 王興鵬
·論著·
AMD3100對胰腺癌細胞AsPC-1及其移植瘤血管生成的影響
高振軍 孔慶云 吳愷 王興鵬
目的探討非肽類特異性CXCR4拮抗劑AMD3100對胰腺癌細胞株AsPC-1細胞增殖及其移植瘤生長的影響。方法AsPC-1細胞分為對照組、基質細胞衍生因子-1(SDF-1α)處理組、AMD3100處理組和SDF-1α+AMD3100處理組,MTT法檢測細胞增殖,Western blotting檢測血管內皮生長因子(VEGF)表達。建立AsPC-1細胞裸鼠移植瘤模型,應用AMD3100瘤內及瘤周注射,觀察移植瘤的生長,免疫組化法檢測裸鼠移植瘤的微血管密度(microvessel density, MVD)。結果SDF-1α可明顯促進AsPC-1細胞增殖(1.430±0.122對1.002±0.001,P<0.05),而同時應用AMD3100處理能抑制這種增殖反應(0.983±0.068 對 1.430±0.122,P<0.05);SDF-1α亦可促進AsPC-1細胞VEGF的表達(0.565±0.047 對 0.439±0.034,P<0.05),而同時用AMD3100處理可抑制這種效應(0.450±0.071 對 0.565±0.047,P<0.05)。AMD3100可抑制AsPC-1細胞皮下移植瘤的生長,第24天的抑瘤率達59.5%,移植瘤的MVD顯著減少(28.56±6.94 對 98.75±20.60,P<0.01)。結論AMD3100在體外和體內均可抑制AsPC-1細胞增殖及其移植瘤的血管生成。
胰腺腫瘤; AMD3100; 細胞增殖; 血管生成
胰腺癌是一種具有高侵襲傾向的惡性腫瘤,80%以上的病例會發(fā)生局部蔓延和淋巴結轉移[1]?;|細胞衍生因子-1(stromal cell-derived factor 1,SDF-1)是一類在腫瘤侵襲轉移中受到越來越多關注的趨化因子,與其受體結合可促進腫瘤的生長、增殖、侵襲、轉移及血管生成[2-3]。AMD3100是一種小分子非肽類特異性CXCR4拮抗劑,屬于雙螯環(huán)類(Bicyclam)化合物,可與CXCR4第二胞外環(huán)的門冬氨酸殘基結合,抑制SDF-1與CXCR4結合,以及由此引發(fā)的下游信號轉導反應。本研究旨在觀察SDF-1α及AMD3100對胰腺癌細胞株AsPC-1細胞增殖及其移植瘤血管生成的影響。
一、細胞培養(yǎng)
人胰腺癌細胞系AsPC-1購自中科院細胞庫,常規(guī)培養(yǎng)傳代。
二、細胞增殖實驗
采用MTT法。取對數生長期細胞,制成單細胞懸液,按5×103個/孔接種于96孔板,貼壁生長后換無血清培養(yǎng)基,分成4組,分別加AMD3100(Sigma-Aldrich公司) 100 ng/ml、SDF-1α(Peprotech公司)100 ng/ml及SDF-1α+AMD3100和只加無血清培養(yǎng)基的對照組,每組設5個平行孔。繼續(xù)培養(yǎng)24 h后,每孔加5 mg/ml的MTT(Sigma-Aldrich公司)20 μl,培養(yǎng)4 h,棄上清液,每孔加150 μl DMSO,振蕩10 min,用酶標儀測定A490值。
三、細胞VEGF蛋白表達檢測
采用Western blotting法。提取上述各組培養(yǎng)24 h細胞的總蛋白,常規(guī)行Western blotting。抗VEGF一抗1∶500稀釋、二抗1∶500稀釋,最后ECL發(fā)光。以β-actin為內參照。圖像掃描儀掃描條帶灰度值,以VEGF條帶與β-actin條帶灰度值比表示VEGF相對表達量。
四、動物及體內成瘤實驗
Balb/c裸鼠,雌性,5~6周齡,體重20 g左右,購自中國科學院上海實驗動物中心(合格證書No.159)。實驗前在SPF級環(huán)境適應性飼養(yǎng)1周。無菌條件下給每只裸鼠背部皮下接種AsPC-1細胞2×106個,以皮下結節(jié)直徑>0.5 mm3為成瘤標準。1周后將10只成瘤裸鼠數字表法隨機分為AMD組和對照組。AMD組在瘤體長徑達0.5 cm時注射AMD3100 7.5 mg/kg體重,一半劑量注入瘤體中央,另一半注射在瘤周,1次/3 d。對照組注射等容積生理鹽水。每3 d測量腫瘤長、短徑,并計算腫瘤體積:V=ab2/2(a為腫瘤長徑,b為腫瘤短徑),繪制腫瘤生長曲線。治療后24 d處死動物,剝取瘤體稱瘤量。抑瘤率(inhibitory rate, IR)=(1 -治療組平均瘤重/對照組平均瘤重)×100%。并將瘤體迅速放入10%甲醛溶液中固定,常規(guī)石蠟包埋、切片。
五、移植瘤微血管密度(MVD)檢測
采用免疫組化SABC染色法,嚴格按免疫組化染色試劑盒(武漢博士德公司)說明操作。以PBS代替一抗作陰性對照。采用雙盲法閱片。結果判斷:以胞質出現棕黃色著色為血管內皮細胞陽性,在腫瘤區(qū)內單個或成叢的內皮細胞均視為單個血管,只要結構不連接,其分支也作為血管,凡管徑>8個紅細胞或帶有肌層的血管不計數。每張切片隨機觀察10個高倍鏡視野(10×40),計數MVD。
六、統(tǒng)計學處理
一、AMD3100對AsPC-1細胞增殖的影響
對照組AsPC-1細胞增殖的A490值為1.002±0.001。AMD3100處理組細胞增殖的A490值為1.005±0.110,與對照組無明顯差異(P>0.05)。SDF-1α處理組細胞增殖的A490值為1.430±0.122,顯著高于對照組(P<0.05),而同時用AMD3100處理,則能抑制細胞增殖反應(P<0.05),A490值為0.983±0.068,與對照組無顯著差異(P>0.05)。
二、 AMD3100對AsPC-1細胞VEGF蛋白表達的影響
對照組、SDF-1α組、AMD3100組和SDF-1α+AMD3100組細胞的VEGF表達量分別為0.439±0.034、0.565±0.047、0.426±0.059和0.450±0.071(圖1)。SDF-1α可促進AsPC-1細胞VEGF的表達(P<0.05),而同時應用AMD3100可抑制這種促進效應(P<0.05)。
三、 AMD3100對AsPC-1細胞裸鼠皮下移植瘤生長的抑制作用
各組裸鼠生長、飲食、活動情況良好,無死亡。移植瘤外觀呈大的球形瘤結節(jié)或數個小的瘤結節(jié)簇生(圖2)。AMD3100組移植瘤生長速度明顯小于對照組(P<0.05,圖3),24 d的IR為59.5%。
圖1 AMD3100對AsPC-1細胞VEGF蛋白表達的影響
圖2 對照組(a)、AMD3100組(b)移植瘤離體圖
圖3 裸鼠移植瘤生長曲線
四、裸鼠皮下移植瘤MVD變化
AMD3100瘤內注射24 d后,移植瘤的MVD為28.56±6.94,明顯低于對照組的 98.75±20.60(P<0.01,圖4)。
圖4AMD3100組(a)和對照組(b)裸鼠皮下移植瘤MVD(IHC ×200)
越來越多的證據表明,在腫瘤微環(huán)境中具有復雜的趨化因子/受體網絡,與腫瘤的生物學行為有關[4],CXCR4在許多惡性腫瘤組織中表達水平明顯升高,SDF-1和CXCR4結合激活特異性信號轉導通路,引起原位和轉移瘤的生長。AMD3100可抑制SDF-1與CXCR4的結合,阻斷隨后的一系列生理過程[5]。
Marchesi等[6]發(fā)現,SDF-1α可促進胰腺癌細胞增殖。本實驗結果顯示,SDF-1α可促進AsPC-1細胞增殖,但這種作用可被AMD3100抑制。體內實驗亦顯示,在AsPC-1細胞皮下移植瘤體及瘤周注射AMD3100可明顯抑制移植瘤的生長,24 d時的抑瘤率接近60%,提示AMD3100在體內外均可顯著抑制CXCR4陽性胰腺癌細胞的增長。
癌細胞在體內生長及侵襲轉移中需有新生血管的存在,VEGF是一種有效的促血管生成因子,它與MVD增加、腫瘤局部侵襲和轉移及術后復發(fā)有關[7]。新近的一項研究認為,VEGF是一種CXCR4下游的靶基因[8]。本實驗結果顯示,SDF-1α可促進AsPC-1細胞VEGF的表達,而AMD3100可抑制這種促進作用,體內實驗亦顯示AMD3100可抑制移植瘤的血管生成。
[1] Lockhart AC,Rothenberg ML,Berlin JD.Treatment for pancreatic cancer: current therapy and continued progress.Gastroenterology,2005,128:1642-1654.
[2] Muller A,Homey B,Soto H,et al.Involvement of chemokine receptors in breast cancer metastasis.Nature,2001,410:50-56.
[3] Kollmar O,Rupertus K,Scheuer C,et al.Stromal cell-derived factor-1 promotes cell migration and tumor growth of colorectal metastasis.Neoplasia,2007,9:862-870.
[4] O′Hayre M,Salanga CL,Handel TM,et al.Chemokines and cancer: migration, intracellular signalling and intercellular communication in the microenvironment.Biochem J,2008,409:635-649.
[5] Flomenberg N,DiPersio J,Calandra G.Role of CXCR4 chemokine receptor blockade using AMD3100 for mobilization of autologous hematopoietic progenitor cells.Acta Haematol,2005,114:198-205.
[6] Marchesi F,Monti P,Leone BE,et al.Increased survival,proliferation,and migration in metastatic human pancreatic tumor cells expressing functional CXCR4.Cancer Res,2004,64:8420-8427.
[7] Niedergethmann M,Hildenbrand R,Wostbrock B,et al.High expression of vascular endothelial growth factor predicts early recurrence and poor prognosis after curative resection for ductal adenocarcinoma of the pancreas.Pancreas,2002,25:122-129.
[8] Billadeau DD,Chatterjee S,Bramati P,et al.Characterization of the CXCR4 signaling in pancreatic cancer cells.Int J Gastrointest Cancer,2006,37:110-119.
2009-10-12)
(本文編輯:屠振興)
EffectofAMD3100ontheproliferationandangiogenesisofAsPC-1cells
GAOZhen-jun,KONGQing-yun,WUKai,WANGXing-peng.
DepartmentofGastroenterology,LianyungangFirstHospital,XuzhouMedicalCollege,Lianyungang222002,China
WANGXing-peng,Email:xpwcn@public7.sta.net.cn
ObjectiveTo investigate the effects of blockade on non-peptide specific SDF-1/CXCR4 receptor ligand system with AMD3100 on the proliferation and angiogenesis of human pancreatic cancer cells AsPC-1.MethodsAsPC-1 was divided into control group, SDF-1α group, group, SDF-1α+ AMD3100 group. MTT test was performed to determine the proliferative level of AsPC-1 cells. Vascular endothelial growth factor (VEGF) was detected with Western blotting assay. Immunohistochemistry was used to detect the microvessel density (MVD) in subcutaneous xenografts of AsPC 1 of nude mice model, which was intratumorally and peritumorally injected with AMD3100.ResultsSDF-1α could induce the proliferation of AsPC-1(1.430±0.122vs1.002± 0.001,P<0.05). While the proliferative effect induced by SDF-1α could be inhibited by AMD3100 (0.983±0.068vs1.430 ± 0.122,P<0.05). SDF-1α could induce the expression of VEGF (0.565 ±0.047vs0.439 ± 0.034,P<0.05). While the protein expression of VEGF induced by SDF-1α on AsPC-1 cells was inhibited by AMD3100 (0.450 ± 0.071vs0.565±0.04,P<0.05). The growth and angiogenesis of subcutaneous xenografts of nude mice model were inhibited by AMD3100; the tumor inhibitory rate was 59.5% at 24th day. The MVD of xenografts was significantly decreased (28.56±6.94vs98.75±20.60,P<0.01).ConclusionsAMD3100 could inhibit the proliferation and angiogenesis of AsPC-1 cells both in vitro and in vivo.
Pancreatic neoplasms; AMD3100; Cell proliferation; Angiogenesis
10.3760/cma.j.issn.1674-1935.2010.05.010
222002 連云港,徐州醫(yī)學院附屬連云港醫(yī)院消化科(高振軍、孔慶云);上海交通大學附屬第一人民醫(yī)院消化科(吳愷);同濟大學附屬第十人民醫(yī)院消化科(王興鵬)
王興鵬,Email: xpwcn@public7.sta. net. cn