黏蛋白1多肽对T淋巴瘤Jurkat 细胞生长的抑制及其机制

目的:探讨黏蛋白1(mucin 1,MUC1)多肽对人T淋巴瘤Jurkat 细胞生长的抑制作用及其机制。方法：将MUC1多肽与Jurkat细胞共同培养,锥虫蓝染色法观察MUC1多肽对该细胞生长的影响;流式细胞术检测Jurkat细胞生长周期及其细胞表面MUC1的表达;Annexin V/PI双标记法检测Jurkat细胞的凋亡;应用抗体封闭实验检测MUC1多肽在Jurkat细胞表面作用的位点。结果： 10、20、40 μg/ml MUC1多肽作用使Jurkat细胞生长抑制分别达（32±4）%、（37±2）%、（46±5）%,未见凋亡细胞。流式细胞术检测结果表明MUC1多肽可诱导Jurkat细胞周期阻滞在G0/G1期,在Jurkat细胞表面有MUC1蛋白的表达。采用5 μg/ml和25 μg/ml 抗MUC1抗体封闭Jurkat细胞表面MUC1表位后,MUC1多肽对细胞生长的抑制效应几乎全部消失。结论： MUC1多肽能明显抑制Jurkat细胞生长,其机制与该多肽通过和Jurkat细胞表面MUC1蛋白相互作用导致细胞周期阻滞在G0/G1期有关。     

应用噬菌体随机肽库筛选肿瘤MUC1/Y黏蛋白结合肽

目的：探索用噬菌体随机肽库筛选可用于肿瘤导向治疗的新型小分子载体。方法：以MUC1/Y黏蛋白的胞外段蛋白（MUC1/Yex）为靶分子,用凝胶亲和法和酶联板法分别筛选十二肽噬菌体随机肽库,ELISA鉴定阳性克隆,DNA序列测定后确定MUC1/Yex结合肽的氢基酸序列;免疫组化鉴定阳性噬菌体克隆及正常及肿瘤细胞的结合能力及特异 性。结果：通过4轮筛选,共获得3种MUC1/Yex的结合肽,分别为HHWHSRSQLSWF,HLKHKNYLPPTP和GNWYRHPHYLQP,其中HXXHS表位可能在与MU1/Yex的结合中起重要作用。阳性噬菌体克隆可与肿瘤细胞系MCF7,OVCA3,而不与正常外周血淋巴细胞结合。结论：筛选获得的MUC1/Yex结合肽具有一定的亲合力和肿瘤特异性,可进一步用于肿瘤导向治疗的研究。     

环氧合酶-2抑制剂塞来昔布诱导人肝癌细胞凋亡及其机制

目的：探讨环氧合酶2（cyclooxygenase2,COX2）抑制剂塞来昔布（celecoxib）诱导人肝癌细胞系SMMC7721凋亡的作用及其可能机制。方法：以10、25、50、75、100 μmol/L的塞来昔布处理SMMC7721细胞,MTT法检测肿瘤细胞增殖,Hoechst 33342/PI 双染法检测细胞凋亡的形态特征,流式细胞术检测细胞凋亡率和细胞周期变化。RTPCR法检测Fas和Bcl2mRNA的表达,Western blotting检测细胞Fas和Bcl2 蛋白的表达。结果：塞来昔布以剂量依赖的方式抑制SMMC7721细胞增殖。塞来昔布作用后,SMMC7721细胞出现核染色质凝集、核膜破裂等凋亡细胞典型的形态特征。25、50和100 μmol /L塞来昔布诱导SMMC7721细胞的凋亡率分别为(16.32±2.32)%、(38.05±2.47)%、(71.17±3.19)%,并使细胞阻滞于G0/G1期。塞来昔布处理后,SMMC7721细胞Fas mRNA及蛋白表达明显增强（P<0.01）;Bcl2 mRNA表达无明显变化（P>005）,高浓度塞来昔布可下调Bcl2蛋白表达（P<0.01）。结论：塞来昔布能够抑制SMMC7721细胞增殖并诱导凋亡,其机制可能与影响凋亡相关基因表达有关。     

含AFP基因调控序列的pAFP-P53-EGFP质粒诱导AFP阳性肝癌细胞凋亡

目的：观察含AFP基因调控序列的载体对AFP阳性肝癌细胞的靶向致凋亡作用。方法：将AFP启动子、沉默子和远端增强子Ⅲ组合为1.2 kb的AFP基因调控序列,构建pAFPEGFP载体,分别转染人肝癌HepG2（AFP阳性）、人肝癌SMMC7721（AFP阴性）和人宫颈癌HeLa（AFP阴性）细胞,荧光显微镜下观察EGFP荧光蛋白表达强度。引入P〖STBX〗53〖STBZ〗基因片段,构建pAFPP53EGFP重组质粒,转染HepG2、SMMC7721和HeLa细胞,Western blotting检测各组细胞P53蛋白的表达,流式细胞术分析各组细胞凋亡率及细胞周期。结果：成功构建了pAFPEGFP和pAFPP53EGFP重组质粒。pAFPEGFP转染后,AFP阳性的HepG2细胞中EGFP荧光蛋白表达显著高于AFP阴性的SMMC7721和HeLa细胞。pAFPP53EGFP转染后,HepG2细胞中P53蛋白的表达量明显高于SMMC7721和HeLa细胞;HepG2细胞的G1期细胞及细胞凋亡率明显高于SMMC7721和HeLa细胞\[(66.7±0.25)% vs（50.5±0.18）%,（51.0±0.20）%,P<0.05;（2.65±008）% vs（0.42±003）%,（0.39±0.02）%,P<0.05\], 但S期细胞明显低于转染后SMMC7721和HeLa细胞\[(20.1±022)% vs（29.8±018）%,（37.8±0.21）%,P<0.05\]。结论：含AFP基因调控序列的pAFPP53EGFP载体可专一性地作用于AFP阳性肝癌细胞,引起肝癌细胞周期阻滞和凋亡。     

siRNA封闭BRCAA1基因对乳腺癌细胞MCF-7增殖和Rb基因表达的影响

目的：〖HT5"SS〗 研究siRNA封闭乳腺癌抗原相关基因1(BRCAA1)对乳腺癌细胞MCF7增殖和Rb基因表达的影响。〖HT5W〗方法： 〖HT5"SS〗采用RNAi技术对乳腺癌细胞MCF7细胞BRCAA1基因进行特异性抑制,用阳离子脂质体与化学合成的Predesigned antiBRCAA1 siRNA构建转染复合体,反转染MCF7细胞株48h后提取总RNA,分为未处理(NT)组、阴性对照组、阳性对照组和BRCAA1组,经反转录荧光实时PCR检测BRCAA1和Rb基因mRNA表达情况;检测细胞增殖抑制率。〖HT5W〗结果： 〖HT5"SS〗与阴性对照组相比,siRNA转染MCF7细胞后实验组BRCAA1基因mRNA水平降低了42.3％;Rb基因表达较之阴性对照组上升了11.1％;实验组MCF7细胞增殖抑制率为（81.9±6.1）％,抑制作用明显强于对照组(P<0.05)。〖HT5W〗结论： 〖HT5"SS〗BRCAA1基因的封闭明显抑制了MCF7细胞的增殖,BRCAA1基因与Rb基因可能存在有某种相互拮抗的作用。     

MUC1肿瘤抗原表位PDTRP基因免疫诱导的体内外抗瘤效应

目的：构建MUC1肿瘤抗原表位γ1neoPDTRP质粒，基因免疫诱导机体产生有效的体内外抗瘤效应。方法： 用Insight Ⅱ将PDTRP抗原表位与MUC1分子模拟，构建含PDTRP的抗原化抗体表达质粒γ1neoPDTRP，体外转染检测表达。用该质粒基因免疫小鼠，免疫后ELISA动态检测血清中抗PDTRP抗体的产生及特异性细胞免疫应答；以4T1PDTRP肿瘤细胞攻击经γ1neoPDTRP免疫小鼠，观察免疫保护效应。结果：三串联肿瘤抗原表位PDTRPDTRPDTRP模拟了MUC1核心序列的空间结构；构建γ1neoPDTRP质粒并在体外转染表达，基因免疫小鼠诱导出特异性抗PDTRP体液和细胞免疫应答，免疫小鼠对4T1PDTRP肿瘤细胞的攻击具有显著的体内保护效应。结论：MUC1肿瘤抗原表位PDTRP可模拟MUC1核心序列的天然构象， γ1neoPDTRP基因免疫在体外诱导特异性的体液和细胞免疫应答，体内诱导对机体的免疫保护效应。     

重组人MUC1-MBP融合蛋白的抗肿瘤作用

目的： 研究重组人MUC1MBP的抗肿瘤作用。方法：用重组人MUC1MBP皮下注射途径免疫健康鼠，采用MTT法测定小鼠抗MUC1特异的CTL活性；通过免疫鼠成瘤及荷瘤鼠治疗实验检测其对肿瘤的预防和治疗作用。结果：MUC1MBP免疫鼠CTL对MCF7及Lewis肺癌细胞的杀伤率分别为(47.7±4.3) %和(67.5±6.5) %；免疫鼠成瘤结果免疫组小鼠共长5个肿瘤，存活时间明显延长，对照组共长51个，平均生存时间23 d；荷瘤鼠治疗结果显示治疗组小鼠肿瘤平均体积386 mm3，对照组小鼠肿瘤平均体积4 000 mm3。结论：重组人MUC1MBP具有明显的治疗、预防肿瘤和抑制肿瘤转移的作用,有希望发展成人类抗肿瘤疫苗。     

重组复制缺陷型腺病毒Ad p53AIP1的抗肿瘤效应及其作用机制

目的:探讨外源性p53AIP1（p53regulated apoptosisinducing protein 1）基因抗肿瘤效应及其作用机制，以评估p53AIP1基因在肿瘤基因治疗中应用的可行性。方法：构建携带p53AIP1基因的重组复制缺陷型腺病毒Adp53AIP1，感染人肝癌细胞HepG2，应用MTT比色法、Western blotting、流式细胞术、罗丹明染色以及电镜等观察外源性p53AIP1基因表达对肿瘤细胞的作用及其相关机制。小鼠皮下接种感染Adp53AIP1的小鼠乳腺癌4T1细胞，观察Adp53AIP1对肿瘤细胞体内成瘤性的影响;建立4T1细胞皮下移植瘤小鼠模型, 直接瘤内多点注射重组腺病毒，观察Adp53AIP1的抗肿瘤疗效。结果：感染Adp53AIP1的HepG2细胞能够高效表达P53AIP1蛋白。MTT检测显示Adp53AIP1对人肝癌细胞HepG2的生长抑制率达50％以上；流式细胞术分析证实p53AIP1使肿瘤细胞周期阻滞于G2/M期；罗丹明染色、电镜观察以及凋亡相关蛋白PARP表达的检测均证实p53AIP1 能诱导肿瘤细胞发生明显凋亡。感染Adp53AIP1的肿瘤细胞体内成瘤受到非常明显的抑制（P<001）, Adp53AIP1瘤体注射对移植瘤生长也有明显的抑制作用（P<0.05）。Western blotting以及RTPCR检测证实Adp53AIP1对p53mRNA表达无影响，能下调mdm2 基因的表达；p53AIP1能上调P53蛋白的表达、下调MDM2蛋白的表达水平，同时还影响P21等细胞周期相关蛋白和凋亡相关蛋白的表达。结论：p53AIP1有明显的体内外抗肿瘤作用，其作用机制与其反向调控P53蛋白、调控多种细胞周期和细胞凋亡相关蛋白、诱导细胞周期阻滞和细胞凋亡有关，该基因在肿瘤基因治疗中具有潜在的应用前景。     

靶向IGF1R的siRNA抑制人肝癌细胞SMMC7721裸鼠移植瘤的实验研究

背景与目的:利用小干扰RNA(small interfering RNA,siRNA)抑制哺乳动物基因表达已成为研究基因功能的一种有效方法.本研究探讨人胰岛素样生长因子1类受体(insulin-like growth factor 1 receptor,IGF1R)的短发夹环RNA对人肝癌细胞株SMMC7721裸鼠移植瘤的抑制作用.方法:设计并合成特异性靶向IGFIR的siRNA片段,构建SMMC7721-IGFlR-siRNA表达质粒,将其转入SMMC7721细胞.通过G418筛选出稳定株,移植裸鼠成瘤.同时设立对照组.根据体积的均数值绘制肿瘤生长曲线,以HE染色法观察质粒处理后瘤组织的病理改变,Western blot检测肿瘤组织中IGF1R的表达变化,免疫组化SP法检测检测瘤组织内微血管密度,原位末端标记法(TUNEL法)检测肿瘤细胞的凋亡情况.结果:SMMC7721-IGF1R-siRNA组肿瘤体积与SMMC7721-IGF1R-mutation组、SMMC7721组相比差异有统计学意义(P＜0.05).病理学检查及TUNEL检测发现,SMMC7721-IGF1R-siRNA组肿瘤生长受到抑制,细胞凋亡指数[(50.2±6.4)%]明显高于SMMC7721.IGF1R-mutation 组[(5.4±1.0)%]和SMMC7721组[(6.0±2.1)%](P＜0.05).SMMC7721-IGF1R-siRNA组与SMMC7721-IGF1R-mutation 组、SMMC7721相比,瘤内IGFIR蛋白表达明显下调.SMMC7721-IGF1R-siRNA组微血管密度(11.3±4.4)与SMMC7721-IGF1R-mutation组(36.7±7.6)、SMMC7721组(28.4±6.5)相比明显下降(P＜0.05).结论:构建的SMMC7721-IGF1R-siRNA具有RNA干扰作用,能抑制SMMC7721细胞裸鼠移植瘤的生长.     

叶绿酸铜钠对SMMC7721肝癌细胞抑制作用的体外实验研究

[目的]研究叶绿酸铜钠（CHL）体外抑制SMMC7721肝癌细胞的作用及机制。[方法]（1）MTT法测半数抑制浓度（IC50）并绘制生长曲线;（2）流式细胞仪观察CHL对SMMC7721细胞凋亡的诱导作用;（3）免疫组化方法检测增殖细胞核抗原（PCNA）、细胞周期素D1（Cyclin D1）、环氧化酶-2（COX-2）的表达。[结果]（1）CHL对SMMC7721细胞具有增殖抑制作用,且具有浓度和时间依赖效应;（2）CHL能诱导SMMC7721细胞G1期阻滞,通过抑制细胞生长周期、降低细胞增生速率抑制肿瘤细胞增殖;（3）CHL对SMMC7721细胞凋亡无明显诱导作用;（4）CHL能下调SMMC7721细胞PCNA和COX-2蛋白表达,并呈一定的浓度依赖性。对Cyclin D1的表达无明显影响。[结论]CHL能抑制SMMC7721细胞的生长,这种抑制作用同PCNA、COX-2表达下调及细胞G1期阻滞有关,但与细胞凋亡和Cyclin D1的表达无关。     

Circulating anti-MUC1 IgG antibodies as a favorable prognostic factor for pancreatic cancer

MUC1 is immunogenic in vivo and humoral and cellular immune responses against MUC1 have been detected in cancer patients. Our study explored the association of circulating anti-MUC1 antibodies with clinicopathological parameters or patients' survival of pancreatic cancer. Serum specimens from 36 patients with invasive ductal carcinoma of the pancreas were subjected to enzyme immunoassay for anti-MUC1 IgG or IgM antibodies. Serum levels of anti-MUC1 IgG antibodies were significantly correlated with survival time (p = 0.0004), whereas neither those of anti-MUC1 IgM nor anti-Galalpha(1,3)Gal IgG antibodies, the latter known as natural antibodies cross-reactive with MUC1, showed a given tendency. Some patients' sera with the higher antibody titer showed the reactivity with MUC1-transfectants of cultured pancreatic cancer cells, but not with MUC1-negative parental cells. When the samples were tentatively divided into 2 groups by the serum level of anti-MUC1 IgG antibodies, the survival of patients was significantly longer in the group with optical density >or=0.3 than in that with optical density <0.3 (p = 0.008). Circulating anti-MUC1 IgG antibody levels remained significant (HR, 0.03; 95% CI, 0.003-0.289; p = 0.0024) after multivariate analysis for pTNM stage, patient age and gender. These data suggest that circulating anti-MUC1-IgG antibody levels may be predictive for survival of pancreatic cancer patients.     

The MUC1 oncoprotein as a functional target: immunotoxin binding to alpha/beta junction mediates cell killing

MUC1, a heavily glycosylated mucin, has generated considerable interest as a target for tumor killing because of its overexpression in malignancies. Full-length MUC1 (MUC1/TM) is proteolytically cleaved after synthesis generating alpha and beta subunits, which specifically bind in a noncovalent interaction. Although the beta chain remains on the cell surface, the alpha chain binds in an on-and-off interaction. Most anti-MUC1 antibodies (Abs) described to date recognize epitopes within the highly immunogenic alpha-chain tandem repeat. Because the alpha-chain is shed, such Abs are sequestered and fail to reach MUC1-expressing cells. Immunizing with cDNA encoding MUC1/TM and the spliced MUC1/X isoform from which the tandem repeat has been deleted yielded antibodies to the MUC1 alpha/beta junction. Pseudomonas toxin PE38 linked to polyclonal anti-MUC1 alpha/beta junction Abs both bound and killed MUC1-positive malignant cells. Monoclonal DMC209 binds the MUC1 alpha/beta junction in both MUC1/X and MUC1/TM. When injected into SCID mice xenotransplanted with human breast cancer MDA-MB-231, monoclonal DMC209 showed significant in vivo tumor-suppressive activity. The MUC1/X alpha/beta junction presents a biologically-significant target in MUC1-expressing malignancies because (i) antibodies directed against cell-bound alpha/beta junction epitopes reach the intended cellular target, (ii) antibodies to junction epitope are internalized into cells, (iii) anti alpha/beta junction antibodies can effectively kill high MUC1-expressing cancer cells as antibody-toxin conjugates and (iv) antibodies targeting the MUC1 cell-bound alpha/beta junction results in tumor suppression in vivo. Our results indicate that cell-bound MUC1 alpha/beta junction, unlike shed alpha chain, represents a highly effective moiety for targeting and killing MUC1-expressing malignancies.     

MUC1 isoform specific monoclonal antibody 6E6/2 detects preferential expression of the novel MUC1/Y protein in breast and ovarian cancer.

The products of the MUC1 gene are known to be highly expressed in human breast cancer cells. The best characterized MUC1 protein is a polymorphic, type 1 transmembrane molecule containing a large extracellular domain composed primarily of a variable number of 20 amino acid tandem repeats. We have recently identified a novel protein product of the MUC1 gene, the MUC1/Y protein, that is also a transmembrane protein but is devoid of the tandem repeat array and its immediate flanking sequences. To analyze its expression in tumor cells we generated monoclonal antibodies directed against the MUC1/Y extracellular domain (anti-MUC1/Yex MAbs). Epitope mapping identified the MAb, 6E6, which recognized the MUC1/Y isoform with exquisite specificity- the repeat-array-containing MUC1 isoform could not compete out this immunoreactivity. A 30mer peptide which is unique for MUC1/Y and corresponds to the "join" region generated by the MUC1/Y specific splice, abrogated all 6E6 MAb immunoreactivity towards MUC1/Y. Immunoprecipitation of the MUC1/Y protein with 6E6 MAbs revealed that, in contrast with the proteolytic cleavage of the tandem-repeat-array-containing MUC1 isoform, MUC1/Y is not cleaved. Flow cytometry analyses using the 6E6 MAbs demonstrated that the MUC1/Y isoform is expressed on the cell surface of both MCF-7 breast cancer cells and malignant epithelial cells present in effusions obtained from breast and ovarian cancer patients. Our results unequivocally establish that the MUC1/Y protein is expressed on the surface of breast cancer cells and cells of other epithelial malignancies. The anti-MUC1/Y MAbs described here can target MUC1/Y expressing tumor cells in vivo and are likely to be important reagents both for epithelial tumor diagnosis and immunotherapy.     

Upregulated expression of complement inhibitory proteins on bladder cancer cells and anti-MUC1 antibody immune selection

Membrane complement inhibitors (CD46, CD55 and CD59) are upregulated in some human cancers indicating that they play a role in immune evasion. We investigated complement inhibitor expression in bladder cancer and examined the hypothesis that selective pressure of an antibody response (anti-MUC1) results in the upregulated expression of complement inhibitors on tumor cells. Paired samples of tumor and normal tissue from 22 bladder cancer patients were analyzed for expression of MUC1, CD46, CD55 and CD59, and matched serum samples analyzed for anti-MUC1 IgM and IgG levels. Relationships between anti-MUC1 antibody levels and complement inhibitor expression were investigated. MUC1 mRNA was upregulated in 86% of tumor samples. CD46 was upregulated in 77%, CD55 in 55% and CD59 in 59% of tumors. Low titer anti-MUC1 IgM was detected in normal human sera, but was elevated in 41% of the bladder cancer patients. Anti-MUC1 IgG was virtually absent from normal sera, but present in 32% of the cancer patients. There was a direct relationship between anti-MUC1 antibody titer and expression level of complement inhibitors. Analysis of the correlation of each antibody with the expression of each complement inhibitor by Spearman's rank test revealed a strong correlation between both anti-MUC1 IgM and IgG levels and increased expression of CD46 and CD55, and combined anti-MUC1 IgM/IgG levels correlated with increased expression of all 3 complement inhibitors. In conclusion, the data demonstrate upregulated complement inhibitor expression and the presence of an anti-MUC1 antibody response in bladder cancer patients and support the hypothesis of antibody-mediated immune selection.     

MUC1和CK7在乳腺癌外周血微转移检测中的应用

目的：以MUC1和CK7为基因标志物检测乳腺癌患者外周血中播散的肿瘤细胞，探讨肿瘤基因标志物在乳腺癌微转移诊断中的意义。方法：采用RT—PCR法检测乳腺癌患者外周血中有核细胞的MUC1和CK7mRNA表达。结果：1）检测15例正常人外周血MUC1、CK7mRNA表达，结果无假阳性；将乳腺癌细胞系MCF-7分别以1：10^5、1：10^6与正常外周血有核细胞混合，检测MUC1、CK7表达，结果无假阴性。2）检测35例乳腺癌患者外周血，以MUC1为标志物，外周血中肿瘤细胞检出率为30_3％（11／35）；以CK7为标志物，外周血中肿瘤细胞检出率为35．0％（12／35）。3）35例患者中有4例MUC1、CK7均表达阳性，7例仅MUC1表达阳性，8例仅CK7表达阳性，两种肿瘤标志物表达患者有交叉但不重叠。结论：以MUC1、CK7为基因标志物，采用RT—PCR方法检测乳腺癌患者外周血中的肿瘤细胞可能在乳腺癌微转移诊断及乳腺癌预后中具有意义，多种肿瘤基因标志物联合检测结果优于单一标志物检测。     

Tissue and Serum MUC1 Mucin Detection in Breast Cancer Patients

Tumor MUC1 expression as well as levels of MUC1, MUC1 circulating immune complexes (MUC1-CIC) and free antibodies against MUC1 (IgG and IgM-MUC1) were evaluated in 70 breast cancer patients with different stages of disease. Controls included: 135 serum samples from healthy women, normal mammary tissue samples (n=7) and benign breast disease specimens (n=6). In all assays, pre- and post-vaccination serum samples from breast cancer patients belonging to a vaccination protocol developed at the Memorial Sloan Kettering Cancer Center (New York, USA) were included as controls. Serum MUC1 was measured through Cancer Associated Serum Antigen test and CA15-3 test. Employing ELISA, MUC1-CIC-IgG/M were measured with either C595 or SM3 monoclonal antibodies (MAb) as catchers and also free antibodies against MUC1 (IgG and IgM) using 100mer peptide as catcher. Employing multivariate statistical analysis, results were correlated with age, tumor type, stage of disease and grade of differentiation. By quantitative immunohistochemistry using three anti-MUC1 core protein MAbs (C595, HMFG2 and SM3), tumor MUC1 was detected in 60/70 (86%) breast cancer specimens which reacted with at least one of these MAbs. High MUC1 serum levels were detected in 14/67 (21%); IgG and IgM anti-MUC1 antibodies were found elevated in 32 and 14%, respectively, while IgG-MUC1-CIC-measured with C595 in 42% and IgM-MUC1-CIC in 54%; finally, SM3 was positive in 43 and 18%, respectively. Results of these studies demonstrate that in a group of breast cancer patients, MUC1 was detected both in tissue specimens as well as free in serum samples; furthermore, MUC1 can also circulate complexed with IgG and IgM antibodies; thus an accurate measurement should include free and complexed forms. On the other hand, immunohistochemical studies on breast cancer tissues may contribute to reveal different MUC1 glycoforms.     

Epitope mapping of PR81 anti-MUC1 monoclonal antibody following PEPSCAN and phage display techniques

PR81 is an anti-MUC1 monoclonal antibody (MAb) which was generated against human MUC1 mucin that reacted with breast cancerous tissue, MUC1 positive cell line (MCF-7, BT-20, and T-4 7 D), and synthetic peptide, including the tandem repeat sequence of MUC1. Here we characterized the binding properties of PR81 against the tandem repeat of MUC1 by two different epitope mapping techniques, namely, PEPSCAN and phage display. Epitope mapping of PR81 MAb by PEPSCAN revealed a minimal consensus binding sequence, PDTRP, which is found on MUC1 peptide as the most important epitope. Using the phage display peptide library, we identified the motif PD(T/S/G)RP as an epitope and the motif AVGLSPDGSRGV as a mimotope recognized by PR81. Results of these two methods showed that the two residues, arginine and aspartic acid, have important roles in antibody binding and threonine can be substituted by either glycine or serine. These results may be of importance in tailor making antigens used in immunoassay.     

Usefulness of Salivary and Serum Auto-antibodies Against Tumor Biomarkers HER2 and MUC1 in Breast Cancer Screening

Background: The aim of this work was to investigate if serum and salivary auto antibodies, isotypes IgG and IgM, against HER2 and MUC1 tandem repeat fragments could play a role in breast cancer screening. Materials and Methods: Our case-control study was conducted in breast cancer patients, in early stages (n=29), at the gynecology service, Maternity Souissi Hospital, Rabat, Morocco and healthy woman (n=31). Salivary and serum auto-antibodies against HER2 and MUC1 (tandem repeat) were assessed by enzyme-linked immunosorbent assay (ELISA) and compared between patients and healthy women using the Mann Whitney U test. A P-value <0.05 was considered to be statistically significant. Results: Our data showed higher expression of all serum and salivary autoantibodies in patients as compared to healthy women p<0.05. However, serum IgM anti-MUC1 expression did not show a significant difference between cases and controls (p=0.79). Similarly, salivary IgG anti-HER2 expression did not differ (p=0.15). The correlation between the different isotypes of antibodies revealed that the highest correlation was between salivary IgG anti-HER2 and salivary IgG anti- MUC1(r=0.65). In fact, we have found in saliva the correlation between autoantibodies anti-MUC1 and anti HER2 more important than in serum (r=0.59 and r=0. 55). However, the correlation between serum and saliva values for all antibodies was weak. Conclusions: Autoantibodies against HER2 and MUC1 may provide a useful approach in breast cancer screening when using both serum and saliva values.     

Protection against MUC1 expressing mouse tumours by intra-muscular injection of MUC1 cDNA requires functional CD8+ and CD4+ T cells but does not require the MUC1 tandem repeat domain

Using a C57Bl/6 mouse model system, where intramuscular (i.m.) injection of full length (FL) MUC1 cDNA protects against subsequent challenge with MUC1-expressing syngeneic tumour cells, we have investigated the importance of the tandem repeat (TR) domain in the induction of T cell-dependent tumour rejection. A MUC1 construct engineered to remove the TR domain (MUC1 0TR) was found to be as effective as the full length MUC1 cDNA in inhibiting the growth of RMA MUC1 cells in C57Bl/6 mice. Protection by i.m. injection of either the FL-MUC1 cDNA or the MUC1 0TR construct depended on the presence of functional CD4+ and CD8+ T cells. Specific CD8+ T cell responses, however, could not be detected in vitro using mouse spleen cells taken after only cDNA injection, but only after challenge in vivo with MUC1-expressing tumour cells. To attempt to enhance the responses of CD4+ T cells, a cDNA construct was developed, where the extracellular domain of MUC1 was fused to the transmembrane and cytoplasmic domain of Lamp1 (MUC1/Lamp1). This construct was equally effective in inducing tumour rejection but did not induce MUC1-specific CTL in mice before challenge with MUC1-expressing tumour cells. Our results indicate that, in this model, T cell responses necessary for protection against MUC1-expressing tumours that are induced by IM injection of MUC1 cDNA are independent of the tandem repeat domain as well as the transmembrane and cytoplasmic domains. A low level of protection was seen with all constructs in BALB/c mice, which show a defect in Th1 responses. C57Bl/6xBALB/c hybrids were, however, well protected against both H2(d) and H2(b) expressing tumour challenge, emphasizing the importance of the host background.     

MUC1 peptide vaccination in patients with advanced pancreas or biliary tract cancer

BACKGROUND: To evaluate the immunogenicity of MUC1 peptide vaccine in advanced pancreatic and bile duct cancers, a phase I clinical trial was conducted. MATERIALS AND METHODS: A 100-mer MUC1 peptide consisting of the extracellular tandem repeat domain and incomplete Freund's adjuvant were subcutaneously administered to 6 pancreatic and 3 bile duct cancer patients at weeks 1, 3 and 5 and doses ranging from 300 to 3000 microg. Circulating intracytoplasmic cytokine-positive CD4+ T cells and anti-MUC1 IgG antibodies were measured before and after vaccination. RESULTS: There were no adverse events, except for mild reddening and swelling at the vaccination site. In 8 patients eligible for clinical evaluation, 7 had progressive disease and 1 stable disease with a tendency for increased circulating anti-MUC1 IgG antibody after vaccination. CONCLUSION: This phase I clinical trial revealed the safety of a vaccine containing 100-mer MUC1 peptides and incomplete Freund's adjuvant.