抗肺癌单克隆抗体15A1的靶抗原在肺癌细胞中的表达及其转位特征

目的:分析抗肺癌单克隆抗体15A1的靶抗原在肺癌细胞的表达、亚细胞定位和转位的特征,研究15A1的体内外抑瘤功能,为肺癌靶向治疗提供候选抗体药物及靶标。方法:采用免疫荧光及细胞流式术检测单克隆抗体15A1靶抗原在肺癌细胞中的表达及定位,免疫组化分析其在人肺癌组织中的表达;CCK-8法和裸鼠移植瘤体内抗体抑瘤实验评估该单克隆抗体对肺癌细胞的抑制作用。结果:单克隆抗体15A1识别的抗原在人肺腺癌细胞(A549、ANIP-973、GLC-82、Calu-3、H157、H1299)、人肺鳞癌细胞(GLC-P、H520)、人小细胞肺癌细胞(H446、H209)、人大细胞肺癌细胞(PG、H460)共12种细胞的胞内及胞膜上均有表达,肺腺癌细胞的表达强度明显高于其他病理类型肺癌细胞;该抗原在75%的人肺癌组织中非常特异地上调表达。该抗原在肺腺癌细胞中相当一部分从胞核转位至胞质,在肺鳞癌细胞中仅有小部分从细胞核转位至细胞质;转位抗原的一部分表达于膜表面,并同样是肺腺癌细胞的表达强度强于肺鳞癌细胞。该单克隆抗体体内外显著抑制肺癌细胞的生长,抑瘤率在25%～80%。结论:单克隆抗体15A1在体内外能显著抑制肺癌的生长,其靶抗原在人肺癌组织和细胞中特异上调表达,并能以特定转位模式表达于肺癌细胞膜上,可能是一个肺癌靶向治疗的潜在靶标。     

单克隆抗体12H6的靶抗原在肺癌细胞中的表达及功能研究

[目的]分析抗肺癌单抗12H6的靶抗原在肺癌细胞系和肺癌组织中的表达,研究单抗12H6体内外生物学功能.[方法]细胞免疫荧光、流式细胞荧光法检测单抗12H6靶抗原在3种肺癌细胞系中的表达及其定位,免疫组化法检测其在人肺癌组织中表达及特异性;Transwell法和CCK-8法分别检测12H6体外对肺癌细胞系侵袭和增殖功能的影响.共接种模型裸鼠体内治疗实验研究12H6对移植瘤生长的抑制作用.[结果]单抗12H6的靶抗原在人肺腺癌细胞(A549、GLC-82)、人肺鳞癌细胞(GLC-P)的胞内及胞膜均有表达,在3种细胞系胞膜的表达比例分别为31.2％、15.4％和16.7％.单抗12H6在人肺癌组织中的表达比例为80.6％,较配对癌旁组织显著上调.单抗12H6在体外能明显抑制肺癌细胞侵袭和增殖;体内能明显抑制移植瘤生长,抑制率为40％.[结论]单抗12H6具有优良的体内外抑瘤功能,可能为肺癌靶向治疗提供潜在的靶向治疗药物.     

肺癌抑制性抗体及其抗原的鉴定

目的：鉴定抑制肺癌细胞生长的功能性单克隆抗体1E2及其抗原，为治疗肺癌提供有潜力的靶向抗体治疗剂和分子靶位。方法：采用活细胞荧光、MTT细胞增殖实验、ELISA、动物体内治疗实验等方法检测鼠单克隆抗体1E2对人肺癌细胞增殖的抑制、单抗与癌细胞的结合部位、单抗的亚类和单抗对肺癌移植瘤的抑制，以Western blotting和MALDITOF质谱方法鉴定该功能性单抗的抗原。结果：单抗1E2能够与肺癌细胞GLC82和NCI-H520的细胞膜结合，在体外能够明显抑制肺癌细胞的增殖。动物实验表明单抗1E2能够抑制肺癌移植瘤的生长，抑制率达49％。Western blotting显示其抗原相对分子质量约110000，质谱鉴定该抗原为氨甲酰磷酸合成酶（carbamoyl-phosphate synthetase1，CPS1）。结论：单抗1E2能够在体内外抑制肺癌的生长，具有成为肺癌靶向治疗剂的潜力。该抗体识别的抗原CPS1可表达于肺癌细胞的细胞膜，可能是一个肺癌靶向治疗的新靶位。     

miR-200a抑制YAP1基因表达对肺癌细胞增殖的影响

  目的   研究微小RNA-200a（miR-200a）对肺癌细胞增殖的影响,并探讨其分子机制。   方法   采用Real-time PCR检测15例非小细胞肺癌组织和对应癌旁组织、人肺癌细胞株（A549、NCI-H520、SK-MES-1）及人正常肺支气管上皮细胞株16HBE中miR-200a的表达水平。用CCK-8法检测miR-200a对A549肺癌细胞增殖活性的影响。通过生物信息学方法预测miR-200a可能的靶基因,双荧光素酶报告基因实验结合Real-time PCR和Western blot验证miR-200a对靶基因YAP1的调控作用。CCK-8法检测下调靶基因YAP1对A549肺癌细胞株增殖活性的影响。   结果   miR-200a在非小细胞肺癌组织和肺癌细胞系中表达明显降低（P < 0.01）。上调miR-200a表达后明显抑制A549肺癌细胞的增殖活力（P < 0.01）。双荧光素酶报告基因显示miR-200a可以直接作用于靶基因YAP1的3'-UTR区域抑制荧光素酶活性（P < 0.01）,Real-time PCR和Western blot检测显示上调miR-200a的表达能够明显下调A549肺癌细胞YAP1 mRNA和蛋白的表达水平（P < 0.01）。CCK-8法显示下调YAP1的表达能够明显抑制A549肺癌细胞的增殖活性（P < 0.01）。   结论   miR-200a通过靶向作用于YAP1基因来抑制肺癌细胞的增殖,从而在肺癌中发挥抑癌基因的功能。      

功能差异细胞模型筛选抗肺癌功能性单克隆抗体及其抗原

目的:筛选获取抗肺癌细胞膜的功能性单克隆抗体及其靶抗原，为肺癌靶向治疗提供候选治疗剂及靶标。方法: 将新鲜人肺癌组织细胞免疫BALB/c小鼠,采用脾细胞融合法制备大容量单克隆抗体库。建立肺癌细胞增殖、侵袭、迁移等定向功能差异细胞模型，采用活细胞免疫荧光与功能差异模型筛选其抗原在定向功能（细胞增殖、迁移、侵袭）差异模型细胞膜上差异表达的单抗，再经体外相应功能实验筛选具有抑制作用的功能性单抗，Western blotting鉴定这些单抗的抗原，裸鼠体内抑瘤实验鉴定部分单抗对肺癌的抑制作用。结果: 细胞融合后共获得2 893株杂交瘤克隆，其中与肺癌细胞膜结合反应的309株。分别建立了3种体外肺癌细胞增殖、侵袭、迁移差异模型用于筛选，筛选获得20株单抗能显著抑制肺癌细胞增殖、10株单抗能显著抑制肺癌细胞侵袭、5株单抗能显著抑制肺癌细胞迁移（P<0.05或P<0.01）。Western blotting鉴定了其中6株的抗原。选取其中2株单抗均能在裸鼠体内显著抑制肺癌移植瘤的生长（P<0.05或P<0.01）。结论: 采用大容量功能性单抗库技术结合功能差异细胞模型可批量筛选获得具有体内外抑制肺癌细胞恶性生物学行为的功能性单抗，为筛选肺癌靶向治疗剂及靶标提供了一种潜在的新方法。     

肿瘤相关新基因pp4519在肺癌中的表达差异及初步功能研究

目的探讨肿瘤相关新基因pp4519在肺癌细胞系、人肺癌及癌旁组织中表达差异及其初步生物学功能.方法合成肿瘤相关新基因pp4519特异性多肽,免疫家兔制备兔源性多克隆抗体;从体外细胞集落形成试验,生长曲线,裸鼠体内成瘤试验,半定量RT-PCR,蛋白印迹,免疫细胞化学及免疫组化检测pp4519基因的表达差异,以及转染肺癌细胞系的细胞凋亡检测等方法研究pp4519基因对体内外细胞生长和生物学功能的影响.结果 SPC-A1肺癌细胞系的体外集落形成试验表明,pp4519基因转染组集落形成数明显少于空载体组(P<0.05);转染pp4519基因的肺癌细胞系的裸鼠体内成瘤试验结果表明该基因对SPC-A1细胞系的成瘤有明显抑制作用(P<0.01);瞬时转染细胞的流式细胞凋亡检测结果表明该基因具有促进SPC-A1细胞凋亡的作用;半定量RT-PCR,蛋白印迹检测结果表明肺癌及癌旁组织中pp4519 RNA和蛋白表达无明显差异(P>0.05),但免疫组化结果显示PP4519在人肺癌癌旁组织中的表达略高于肺癌.结论 pp4519是一个具有抑制肺癌细胞生长功能的新基因.     

miR-216a-5p通过下调MMP16表达抑制肺癌细胞的侵袭

背景与目的：微小RNA(microRNA,miRNA)是一类存在于真核生物体内只有19~39 bp大小的内源性非编码RNA,它能在转录和翻译水平调控基因的表达,在细胞的增殖分化、新陈代谢、免疫调控和凋亡等方面起着重要的作用。本研究检测miR-216a-5p在肺癌组织和肺癌细胞系的表达并探讨其对肺癌细胞侵袭能力的影响及其调控机制。方法：使用实时荧光定量PCR(quantitative real-time PCR,qRT-PCR)检测55例肺癌患者的肺癌组织和7种肺癌细胞系中miR-216a-5p的表达情况;miR-216a-5p瞬时转染A549、95D和H460 3种肺癌细胞系,使用Transwell侵袭实验检测miR-216a-5p对肺癌细胞系侵袭能力的影响;预测并构建miR-216a-5p的候选靶基因基质金属蛋白酶16(matrix metalloproteinase 16,MMP16)基因的双荧光素酶报告基因表达质粒,使用qRT-PCR和蛋白［质］印迹法(Western blot)检测miR-216a-5p对靶基因MMP16的mRNA和蛋白表达的影响;小干扰RNA(siRNA)干扰MMP16与上调miR-216a-5p对比检测其对肺癌细胞侵袭能力的影响。结果：90.91%(50/55)的肺癌患者肿瘤组织中miR-216a-5p表达明显低于对应的癌旁组织(P<0.05)。7种肺癌细胞系中miR-216a-5p的表达量仅为对照组的7.00%~32.00%(P<0.05)。上调miR-216a-5p的表达能够抑制肺癌细胞的侵袭;siRNA干扰MMP16与转染上调miR-216a-5p都能够抑制肺癌细胞中MMP16的表达,并抑制肺癌细胞侵袭。结论：miR-216a-5p可以作为临床肺癌诊断的候选标志物之一,并且其能够通过下调MMP16的表达从而抑制肺癌细胞的侵袭。     

131I标记抗肺癌单克隆抗体1 E2在荷瘤小鼠体内分布及对小鼠移植瘤作用

目的:分析碘-131(131I)标记抗肺癌单克隆抗体IE2在荷Lewis肺癌小鼠体内分布,评估瘤内注射碘-131标记抗肺癌单克隆抗体1E2(131I-1E2)对小鼠Lewis肺癌的生长抑制作用.方法:C57BL/6小鼠右后腿皮下接种Lewis肺癌细胞(LLC)l×106只,建立荷Lewis肺癌小鼠模型,免疫组化检测Lewis肺癌细胞(LLC)膜上1E2抗原-氨甲酰磷酸合成酶1(CPS1)的表达.131I标记1E2单抗(氯胺T法),检测标记率、放化纯度、放射性比活度.荷瘤小鼠尾静脉注射标记抗体131I-1E2 18.5 MBq,观察其不同时间点在小鼠体内的分布.成瘤后小鼠随机分为4组,分别瘤内注射生理盐水0.1ml(空白对照),1E2单抗3μg(阳性对照),131I-IGg 18.5 MBq(阴性对照),131I-1E2 18.5 MBq.治疗后每周2次测定肿瘤大小,21天后处死小鼠观察肿瘤组织病理学改变,检测肿瘤体积、重量,计算抑瘤率.结果:1E2抗原-CPs1主要在肿瘤细胞膜表达,131I-IE2标记率为67.73%,放化纯度为95.63%.131I-1E2主要分布在肿瘤组织,治疗后3周试验组肿瘤体积为(0.75±0.15)cm3,重量为(1.60±0.19)g,抑瘤率78.30%,与对照组间比较差异有统计学意义(P<0.01),对照组之间差异无统计学意义(P>0.05).治疗组与对照组间病理学差异显著.结论:131I-1E2瘤内注射可抑制肿瘤的生长,具有潜在的临床应用价值,有可能成为新的肿瘤治疗靶向药物.     

一株抗胰腺癌干细胞单克隆抗体的鉴定及功能研究

目的 对一株抗胰腺癌干细胞单克隆抗体（简称：单抗）进行初步鉴定和体外功能研究,为靶向胰腺癌干细胞治疗胰腺癌提供候选单抗药物.方法 应用无血清悬浮培养及PKH26染色确定胰腺癌细胞系PANC-1中肿瘤干细胞的存在.流式细胞术检测PANC-1细胞中有干细胞标志物CD44＋CD24＋的细胞比例.双色细胞免疫荧光检测CD24和单抗15D2识别的抗原蛋白在PANC-1细胞中的表达情况.无血清悬浮培养法观察单抗15D2对PANC-1成球细胞自我更新的影响.CCK-8法检测单抗15D2对PANC-1细胞增殖和耐药的影响.免疫组织化学检测单抗15D2识别的靶抗原在人胰腺癌、癌旁组织中的表达情况.结果 PANC-1细胞能在无血清培养液中存活、增殖并形成细胞球,成球率为（2.5±0.5）％.PANC-1球体细胞中CD44＋ CD24＋细胞的比例较亲本细胞提高了11.4倍,其中CD44＋ CD24＋细胞占CD24＋细胞的97％,在此体系中用CD24作为PANC-1细胞干细胞标志物.细胞免疫荧光结果显示单抗15D2识别的抗原分子在细胞膜上表达,并能与CD24在PANC-1细胞共定位.抗体体外功能研究发现,单抗15D2能显著抑制PANC-1细胞在无血清培养液中成球,抑制率达到22％.同时,单抗15D2联合吉西他滨能显著抑制PANC-1球体细胞的增殖,联合组和对照组IC50分别为0.10、0.39 μmol/L.免疫组织化学检测结果显示,单抗15D2所识别的抗原蛋白在76.9％（11/13）的人胰腺癌组织中表达阳性,而在癌旁组织中表达阳性率仅为10.0％（1/10）,差异有统计学意义（P＜0.05）.结论 抗胰腺癌干细胞单抗15D2体外能够显著抑制胰腺癌干细胞的自我更新和耐药能力,为胰腺癌干细胞的靶向治疗提供有应用价值的候选抗体药物.     

抗肺癌单抗WLA-2C4对应抗原性质及组织分布特征

作者采用Westem-blotting方法,对一株抗人肺癌单克隆抗体WLA-2C4所识别的肿瘤相关抗原WLA-Agl进行了初步分析.用免疫组织化学方法对WLA-Agl在肺癌、肺外脏器肿瘤以及人体某些正常组织中的表达状态进行了研究.结果表明,WLA-2C4识别的抗原是分子量约58KD的糖蛋白。该抗原主要分布于肺低分化腺癌以及大细胞癌,在肺外脏器的某些低分化癌亦有较强的表达,而在肺内及肺外的高分化癌表达较少.在正常支气管、肺、胃肠粘膜等极少表达.提示由单克隆抗体WLA-2C4所识别的抗原WLA-Agl可能是一种新的肿瘤相关抗原。     

一株靶向CD90+MHCC97-L细胞单克隆抗体治疗肝癌的实验研究

目的:研究抗人肝癌干细胞单抗28C10体内外功能,为肝癌干细胞的靶向治疗提供有应用价值的候选治疗剂。方法:采用无血清成球实验、侵袭实验和CCK-8方法等检测分析28C10单抗对MHCC97-L sphere的细胞自我更新、侵袭和耐药的影响。裸鼠体内治疗实验研究单抗28C10联合顺铂对MHCC97-L移植瘤生长的作用。Western-Blot方法鉴定该单抗识别抗原的分子量。结果:流式细胞检测结果显示单抗28C10能够识别MHCC97-L中CD90阳性细胞的比例为2.75%。体外功能实验结果显示单抗28C10能显著抑制MHCC97-L sphere细胞的无血清成球能力和侵袭能力,抑制率分别达33.33%和53.8%。28C10能显著抑制MHCC97-L sphere的顺铂耐药能力,其IC50为0.74 μg/ml,而对照组的IC50为1.42 μg/ml。抗体体内治疗实验结果显示,低、高剂量抗体28C10均能抑制肝癌移植瘤的生长,抑制率分别达到了24.0%和67.7%,单独顺铂组肝癌移植瘤的抑制率为35.9%,而顺铂联合高剂量抗体28C10组对肝癌移植瘤的抑制率达到70.1%。Western-Blot结果显示单抗28C10识别的抗原蛋白分子量约100 kD。结论:筛选获得了1株抗肝癌干细胞的功能性单抗,为靶向肝癌干细胞治疗肝癌奠定了重要的基础。     

新基因CT120在肺癌组织中的表达及其对细胞生长的影响

背景与目的：基因CT120是我们实验室从染色体17p13.3位点获得的一个细胞膜相关新基因,mRNA水平检测结果表明该基因在人正常肺组织中不表达,但在人肺癌细胞系SPC－A－1中高表达。本研究进一步从蛋白水平研究CT120在肺癌及癌旁组织中的差异表达及CT120异位表达（ectopic expression）与过表达（overexpression）对细胞生长的影响。方法：用生物信息学方法设计15肽,合成并偶联到大分子载体KLH上制成人工免疫原,制备鸡抗CT120多肽抗体;通过Western blotting方法检测CT120在不同肿瘤细胞系中的表达;通过免疫组织化学技术比较CT120在肺癌及癌旁组织中的差异表达;通过集落形成试验研究CT120异位表达对NIH／3T3细胞生长的影响;通过生长曲线及裸鼠成瘤试验研究CT120过表达对A549细胞生长的影响。结果：获得有效的鸡抗CT120抗体（IgY）;CT120蛋白在不同肿瘤细胞系中表达程度不同,并在不同类型的肺癌组织中高表达;CT120基因异位表达显著促进NIH／3T3细胞的生长;同时CT120过表达对A549细胞在体内体外的生长有促进作用。结论：基因CT120与肺癌的发生发展有关,是一个人肺癌相关新基因。     

抗胃癌干细胞单克隆抗体的筛选鉴定及功能研究

目的:筛选鉴定靶向胃癌干细胞的功能性单克隆抗体,为胃癌干细胞靶向治疗提供抗体候选药物。方法:以胃癌细胞系BGC-823为模型,采用流式细胞术分选CD44+细胞后检测其自我更新和致瘤能力。双色细胞免疫荧光检测单抗11H5和CD44在BGC-823细胞中的表达情况。流式细胞术分选11H5+细胞后检测其自我更新能力、细胞增殖和耐药能力。结果:流式细胞术分选CD44+细胞成球率明显高于CD44-细胞［（27.2±1.6）% vs （12.9±1.2）%］（P<0.01）,CD44+细胞的致瘤性比CD44-细胞至少高100倍。细胞免疫荧光结果显示单抗11H5识别的抗原能与CD44在BGC-823细胞上共定位。流式细胞术分选11H5+细胞体外成球率明显高于11H5-细胞［（21.4±2.0）% vs （6.2±1.0）%］（P<0.01）,耐药性也明显高于11H5-细胞(IC50值:0.986 μmol/L vs 0.315 μmol/L)。抗体体外功能研究发现,单抗11H5能显著抑制BGC-823细胞成球,抑制率达到47.9%。单抗11H5能抑制其sphere细胞的增殖,抑制率为44.9%（P<0.05）。经单抗11H5作用的耐药能力显著降低(IC50值:0.52 μg/ml vs 0.64 μg/ml)。结论:单克隆抗体11H5是一株抗胃癌干细胞的功能性单抗,为胃癌干细胞靶向治疗的候选抗体药物。     

Targeted therapy of experimental renal cell carcinoma with a novel conjugate of monoclonal antibody 138H11 and calicheamicin thetaI1

In search for a new therapeutic approach for metastasized renal cell carcinoma (RCC), we evaluated the cytotoxicity of a novel prodrug chemoimmunoconjugate with monoclonal antibody (mAb) 138H11 and the DNA-cleaving enediyne calicheamicin thetaI1 (Camtheta) in vitro and in vivo. Previously, mAb 138H11, produced against human renal gamma-glutamyltransferase, stained over 99% clear cell and papillary RCC on frozen sections, showing a membranous expression of the target antigen. In contrast, in normal kidneys gammaGT was restricted to the brush-border in the lumen of proximal tubules and not accessible to the circulation. Thus, human tumor-bearing kidneys perfused in an extra-corporeal system with 99mTc-138H11 revealed a high, specific uptake into the tumor. In this study, fluorescence-activated cell sorting analysis showed binding of mAb 138H11 to RCC cell lines, whereas squamous cell carcinoma lines, fibroblasts, and the murine RENCA were negative. XTT cell proliferation assays revealed efficient killing of the Caki-1 cell line by the 138H11-Camtheta conjugate using SPDP (EC50 = 5 x 10(-11) M) as a covalent linker. For in vivo testing, five groups of eight nude mice each were injected with 2.5 x 10(6) Caki-1 cells s.c. and treated with the following: (a) PBS; (b) 138H11; (c) Camtheta; (d) a mixture of 138H11 and Camtheta; and (e) 138H11-Camtheta conjugate. Treatment started on day 1 after tumor induction and was repeated three times. The data show a highly significant inhibition of tumor growth with the 138H11-Camtheta conjugate versus PBS (P = 0.004). Only mice treated with 138H11-Camtheta showed a tumor shrinkage to minimal residues. In a second experiment, lower doses of the 138H11-Camtheta conjugate were compared with an antineuroblastoma mAb (ch14.18), confirming targeted killing of RCC by the 138H11-Camtheta conjugate at tolerable toxicity in vivo. In conclusion, these combined results encourage further studies for targeted therapy of metastatic RCC with mAb 138H11 conjugates.     

抗肝癌干细胞单克隆抗体的鉴定及功能

目的:鉴定可靶向肝癌干细胞的功能性单克隆抗体,为肝癌干细胞靶向治疗提供抗体候选药物.方法:以肝癌细胞系Bel7402-V3为模型,采用流式细胞术分选ESA+细胞后检测其耐药能力及致瘤能力.双色细胞免疫荧光检测单抗3G7和ESA识别的抗原蛋白在Bel7402-V3细胞中的表达情况,同时采用此法检测sphere中PKH26与3G7的共染情况.流式细胞术分选3G7+细胞后检测其自我更新能力,并采用CCK-8法检测其耐药能力;甲基纤维素成球实验,检测单抗3G7对细胞自我更新能力的影响;CCK-8法检测单抗3G7对细胞增殖和耐药能力的影响.结果:流式细胞术分选ESA+细胞的耐药性明显高于ESA-细胞,其IC50值分别为2.30 μmol/L、0.49 μmol/L(P<0.01),ESA+细胞的致瘤性较ESA-细胞高至少40倍.细胞免疫荧光结果显示单抗3G7识别的抗原分子能与ESA在Bel7402-V3细胞上共定位,并能与标识干细胞的PKH26染料共染.流式细胞术分选3G7+细胞体外成球率明显高于3G7-细胞[(30.4±3.4)% vs (8.8±1.8)%](P<0.01),耐药性也明显较高(IC50值:1.014 μmol/L vs 0.365 μmol/L).抗体体外功能研究发现,单抗3G7能显著抑制Bel7402-V3的甲基纤维素成球,抑制率达到37.2%;同时,单抗3G7能抑制sphere细胞的增殖,抑制率为41.7%(P<0.01);经单抗3G7处理过细胞的耐药能力显著降低,实验组与对照组的IC50分别为0.56 μg/ml和0.68 μg/ml.结论:单克隆抗体3G7是一株抗肝癌干细胞的功能性单抗,为肝癌干细胞靶向治疗的候选抗体药物.     

In vitro and in vivo targeting properties of iodine-123- or iodine-131-labeled monoclonal antibody 14C5 in a non-small cell lung cancer and colon carcinoma model.

PURPOSE: The monoclonal antibody (mAb) 14C5 is a murine IgG1 directed against a yet undefined molecule involved in cell substrate adhesion found on the surface of malignant breast cancer tissue. mAb 14C5 is able to inhibit cell substrate adhesion and invasion of breast cancer cells in vitro. In normal tissues as well as in the stroma surrounding in situ carcinomas of the breast, no expression of the antigen 14C5 occurs. The aim of this study was to investigate the in vitro and in vivo targeting properties of 123I- and 131I-labeled mAb 14C5 as a novel agent for radioimmunodetection and radioimmunotherapy. EXPERIMENTAL DESIGN: Internalization of mAb 14C5 was investigated with 125I-labeled mAb 14C5 and by confocal laser scanning microscopy. Biodistribution studies of 131I-labeled mAb 14C5 and planar gamma imaging were done in nude mice bearing an A549 (non-small cell lung carcinoma) or a LoVo (colon carcinoma) tumor. RESULTS: Internalization studies with both A549 and LoVo cells showed that 125I-labeled mAb 14C5 is slowly internalized with approximately 30% of the initially bound mAb 14C5 internalized after 2 hours at 37 degrees C. Internalization of mAb 14C5 could be visualized with confocal laser scanning microscopy. In vivo, radioisotope uptake peaked at 24 hours for both tumor models (n = 5) with no significant difference in percentage of injected dose/g tissue (A549 10.4 +/- 0.8 and LoVo 9.3 +/- 0.8). Via planar gamma camera imaging, A549 lung tumors as well as LoVo colon tumors could be clearly visualized. CONCLUSIONS: The in vitro and in vivo targeting properties of 123I- and 131I-labeled mAb 14C5 are promising and could provide a new antibody-based agent for radioimmunodetection and radioimmunotherapy of patients bearing antigen 14C5-expressing tumors.     

Humanized anti-CD26 monoclonal antibody as a treatment for malignant mesothelioma tumors.

PURPOSE: CD26 is a 110-kDa cell surface antigen with a role in tumor development. In this report, we show that CD26 is highly expressed on the cell surface of malignant mesothelioma and that a newly developed humanized anti-CD26 monoclonal antibody (mAb) has an inhibitory effect on malignant mesothelioma cells in both in vitro and in vivo experiments. EXPERIMENTAL DESIGN: Using immunohistochemistry, 12 patients' surgical specimens consisting of seven malignant mesothelioma, three reactive mesothelial cells, and two adenomatoid tumors were evaluated for expression of CD26. The effects of CD26 on malignant mesothelioma cells were assessed in the presence of transfection of CD26-expressing plasmid, humanized anti-CD26 mAb, or small interfering RNA against CD26. The in vivo growth inhibitory effect of humanized anti-CD26 mAb was assessed in human malignant mesothelioma cell mouse xenograft models. RESULTS: In surgical specimens, CD26 is highly expressed in malignant mesothelioma but not in benign mesothelial tissues. Depletion of CD26 by small interfering RNA results in the loss of adhesive property, suggesting that CD26 is a binding protein to the extracellular matrix. Moreover, our in vitro data indicate that humanized anti-CD26 mAb induces cell lysis of malignant mesothelioma cells via antibody-dependent cell-mediated cytotoxicity in addition to its direct anti-tumor effect via p27(kip1) accumulation. In vivo experiments with mouse xenograft models involving human malignant mesothelioma cells show that humanized anti-CD26 mAb treatment drastically inhibits tumor growth in tumor-bearing mice, resulting in enhanced survival. CONCLUSIONS: Our data strongly suggest that humanized anti-CD26 mAb treatment may have potential clinical use as a novel cancer therapeutic agent in CD26-positive malignant mesothelioma.     

Differential expression of the Leu-7 antigen on human lung tumor cells

The HNK-1 monoclonal antibody detects an antigen (Leu-7) on a subpopulation of large granular lymphocytes which have natural killer cell function. Recently this antigen has been found on nonhemopoietic tissues. In the present study human lung tumor cells were examined for the presence of Leu-7 antigen using an enzyme-linked immunosorbent assay, immunoperoxidase staining, and fluorescence-activated cell sorter analysis. All small cell lung tumor cells tested were Leu-7 positive. In contrast only two of seven biopsy specimens from small cell lung cancer patients were Leu-7 positive. Several large cell lung tumor lines were Leu-7 positive while an adenocarcinoma and squamous cell carcinoma were negative. These results indicate that expression of Leu-7 antigen on lung tumor cells is heterogeneous both in vitro and in vivo. Small cell lung tumor lines have been reported to undergo histological conversion in vitro accompanied by the loss of a number of biochemical markers. In our study histologically converted cells exhibited much less reactivity with HNK-1 than did the parent cells. These results indicate that the degree of expression of Leu-7 antigen may be under the control of differentiation-related events. Thus monoclonal antibody HNK-1 has been very useful in studying heterogeneity within and among lung tumor cells.     

E-selectin up-regulation allows for targeted drug delivery in prostate cancer

We have used the Eos Hu03 GeneChip array, which represents over 92% of the transcribed human genome, to measure gene expression in a panel of normal and diseased human tissues. This analysis revealed that E-selectin mRNA is selectively overexpressed in prostate cancer epithelium, a finding that correlated strongly with E-selectin protein expression as assessed by immunohistochemistry. Antibodies against E-selectin that blocked function failed to impede cancer cell growth, suggesting that overexpression of E-selectin was not essential for cell growth. However, a novel auristatin E-based antibody drug conjugate (ADC), E-selectin antibody valine-citrulline monomethyl-auristatin E, was a potent and selective agent against E-selectin-expressing cancer cell lines in vitro, with the degree of cytotoxicity varying with surface antigen density. Interestingly, sensitivity to the ADC differed among cell lines from different tissues expressing similar amounts of E-selectin and was found to correlate with sensitivity to free auristatin E. Furthermore, E-selectin-expressing tumors grown as xenografts in severe combined immunodeficient mice were responsive to treatment with E-selectin antibody valine-citrulline monomethyl-auristatin E in vivo, with more than 85% inhibition of tumor growth observed in treated mice. These findings demonstrate that an E-selectin-targeting ADC has potential as a prostate cancer therapy and validates a genomics-based paradigm for the identification of cancer-specific antigens suitable for targeted therapy.