肝癌高转移细胞株的肿瘤干细胞生物学特性研究

目的:建立高转移肝癌细胞株,研究其肿瘤干细胞生物学特征,为靶向人肝癌干细胞治疗提供有价值的细胞模型。方法:肝癌细胞系Bel7402接种裸鼠皮下,成瘤后,取小鼠肺部转移灶,通过机械分离法,获取肺部肝转移细胞,体外扩大培养后,再次接种裸鼠。如此反复接种裸鼠,获得稳定肺转移肝癌细胞株Bel7402-V13。采用无血清悬浮培养及PKH26染色确定Bel7402-V13中肿瘤干细胞的存在。流式细胞术分析亲本Bel7402和Bel7402-V13中肿瘤干细胞标志物ESA的表达情况,分选Bel7402和Bel7402-V13中ESA+细胞并进行体外生物学特征研究及裸鼠致瘤实验。结果:建立高转移Bel7402-V13细胞株,Bel7402-V13细胞无血清悬浮培养7d后形成的细胞球体中存在单个PKH26阳性细胞。与Bel7402中ESA+细胞相比,流式分析显示干细胞标志物ESA比例高转移Bel7402-V13显著提高5.67倍（17.6±0.4 vs 3.1±1.5）。Bel7402-V13中ESA+细胞具有更强的自我更新能力［成球率:（94.8±7.5）% vs （52.3±6.9）%,P<0.01］,侵袭能力提高1.51倍（397.7±79.4 vs 262.0±40.1,P<0.01）,耐药能力也显著增强（IC50:0.286 vs 0.196,P<0.01）,ESA+细胞Bel7402-V13在裸鼠皮下接种2×102个细胞3月即可致瘤（3/6）,而接种2×102个ESA+细胞Bel7402细胞3月才能致瘤（1/6）。结论:获得高转移肝癌细胞株Bel7402-V13,伴随ESA+细胞增加,其体内外功能显著增强,为肝癌干细胞的靶向治疗提供有价值的细胞模型。     

杂交瘤单抗4F11识别CD90+肝癌干细胞并抑制其侵袭【院士点评：靶向CD90+肿瘤干细胞可能治疗肝癌转移】

目的:筛选识别肝癌干细胞的单克隆抗体并研究其体外的抗肿瘤作用,为肝癌干细胞靶向治疗提供候选抗体药物。方法:无血清悬浮培养及PKH26染色分析人肝癌细胞株MHCC97H中是否存在肝癌干细胞。流式细胞术检测MH-CC97H细胞及其成球细胞中7种肿瘤干细胞标志物的表达,以及MHCC97H细胞中肝癌干细胞标志物CD90和不同杂交瘤单抗3G7、4F11、11C9、15B7、15D2识别抗原的共表达情况。无血清悬浮培养法和CCK8法检测单抗4F11对MHCC97H细胞及其成球细胞自我更新和增殖的影响,Transwell实验检测单抗4F11对MHCC97H细胞体外侵袭和迁移的影响。结果:PKH26染色实验显示,MHCC97H细胞球体由单个肝癌干细胞增殖分化形成。MHCC97H细胞球中CD90+MHCC97H细胞比例较亲本MHCC97H细胞显著增加[(18.0±7.5)%vs(2.3±1.0)%,P<0.05]。杂交瘤单抗4F11、3G7、11C9、15B7、15D2均能识别MHCC97H细胞中CD90+MHCC97H细胞,其中单抗4F11对CD90+MHCC97H细胞的识别比例为(47.2±4.4)%,其对MHCC97H成球细胞增殖的抑制率远大于对亲本MHCC97H细胞增殖的抑制率[(29.4±3.8)%vs(12.0±2.2)%,P<0.05]。单抗4F11抑制MHCC97H细胞成球,抑制率达(58.0±20.8)%。单抗4F11能显著抑制MHCC97H细胞体外侵袭和迁移,抑制率分别为(48.6±5.1)%和(47.6±3.6)%。结论:杂交瘤单抗4F11能特异性识别CD90+肝癌干细胞,抑制肝癌细胞的侵袭和迁移,可作为肝癌干细胞靶向治疗的候选抗体药物。     

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.     

肿瘤干细胞多靶点联合治疗效果分析

[目的]探讨有效的肿瘤生物治疗新思路,用肝癌细胞系Bel7402-V3为细胞模型检测联合单克隆抗体9A9和15D2对其干性功能（自我更新、侵袭和耐药）的影响。[方法]采用活细胞流式免疫荧光术检测单独抗体、联合抗体与肿瘤干细胞标志物ESA在Bel7402-V3亲本及sphere细胞中的表达;甲基纤维素成球实验和Transwell小室侵袭实验分别检测抗体对Bel7402-V3亲本细胞成球能力和侵袭能力的影响;CCK8法及IC50法检测联合抗体对Bel7402-V3亲本细胞耐药能力的影响。[结果]流式荧光结果显示：标志物ESA、单抗15D2、单抗9A9所识别的细胞比例在Bel7402-V3 sphere细胞中比在亲本细胞中分别富集了2.6倍、4.1倍、2.0倍;在Bel7402-V3亲本和sphere细胞中,联合单抗与标志物共染比例（9A9＋15D2与ESA）大于单抗分别与标志物共染比例之和[（9A9＋ESA）＋（15D2＋ESA）];单抗9A9与15D2联合时对Bel7402-V3亲本细胞的成球抑制率和侵袭抑制率均明显高于等浓度的单种单抗对Bel7402-V3亲本细胞的功能抑制;经联合单抗处理的Bel7402-V3亲本细胞耐药能力较经等浓度单种单抗处理的细胞耐药能力显著降低[9A9＋15D2：IC50为0.32μg/ml,9A9：IC50为0.58μg/ml,15D2：IC50为0.56μg/ml。[结论]肿瘤干细胞中存在不同亚群,其在不同的信号通路或基因水平上发挥了不同的作用。联合多靶点的抗体治疗能显著提高疗效。     

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。     

抗肝癌干细胞单抗的体内外功能

目的 探讨一株抗肝癌干细胞单抗H C-7 B2的体、内外功能,为肝癌的靶向治疗提供候选单抗.方法 采用SDS-PAGE电泳法检测抗体纯度.采用无血清成球实验和侵袭实验分析体外HC-7B2单抗对肝癌干细胞自我更新和侵袭的影响.采用CCK8法检测HC-7B2单抗联合顺铂对肝癌干细胞增殖能力的影响.裸鼠体内治疗实验研究单抗H...     

人Sep15的基因克隆和功能的初步研究

背景与目的：Sep15是1998年发现的一种新的硒蛋白。文献报道Sep15可能与肿瘤的发生有关,并参与二硫键的还原。但迄今为止,Sep15的确切功能还不清楚。本实验拟对Sep15与肿瘤的关系及其抗氧化功能进行初步研究。方法：应用RT－PCR方法获得人Sep15的全长cDNA基因,并重组到直核表达载体pcDNA3.1（＋）上,将重组质粒pcDNA3.1-Sep15转染到人肝癌细胞株BEL－7402,得到Sep15高表达的细胞株BEL－7402－Sep15,然后通过一系列体内和体外实验研究Sep15与肝癌细胞的关系及其抗氧化作用。结果：转染Sep15基因不影响肝癌细胞株BEL－7402的细胞的形态、生长速率、克隆形成能力和裸鼠体内肿瘤生长速率;检测不同浓度外源性H2O2氧应激处理后3种细胞BEL－7402－Sep15、BEL－7402-pcDNA3.1和BEL－7402的细胞存活率,结果显示BEL－7402－Sep15的细胞存活率明显高于BEL－7402－pcDNA3.1和BEL－7402（P＜0．05）。结论：转染Sep15基因的肝癌细胞株BEL－7402具有抗氧化的生物学活性。     

一株胃癌干细胞功能性单克隆抗体的鉴定及功能研究

[目的]从抗人胃癌干细胞单克隆抗体杂交瘤库中筛选鉴定识别胃癌干细胞的单克隆抗体,并证明其具有抑制胃癌干细胞自我更新能力和侵袭功能的功能性单抗,为靶向人胃癌干细胞治疗胃癌提供有治疗潜能的单抗候选药物。[方法]采用无血清培养、PKH26染色及流式细胞术等方法确定人胃癌细胞系SNU-5中存在肿瘤干细胞,可作为研究抗人胃癌干细胞单抗的细胞模型。应用双色免疫荧光、流式细胞分选等技术分析鉴定单克隆抗体25G5是识别胃癌干细胞的单克隆抗体。用肿瘤干细胞的成球生长实验、Transwell侵袭实验及耐药性实验研究分析25G5单抗对胃癌干细胞功能的影响。[结果]SNU-5细胞在无血清培养基中存活并增殖成球形生长,SNU-5球体细胞中表达胃癌干细胞标志物CD44~+和CD90~+的细胞比例分别为72.4%和8.55%,较亲本细胞分别提高了21.3倍和2.4倍,表明SNU-5中存在有CD44~+、CD90~+的胃癌干细胞。细胞免疫荧光结果显示25G5单抗识别的抗原分子与CD44、CD90胃癌干细胞标志物共染表达于胃癌干细胞膜上。流式细胞术分选的25G5~+细胞的成球率为(21.4±0.3)%,显著高于25G5-细胞(12.3±0.7)%和亲本细胞(16.1±1.0)%。Transwell侵袭实验、细胞耐药性实验和动物体内致瘤实验结果显示25G5~+细胞的侵袭能力和耐药能力也显著高于25G5-细胞和亲本细胞,表明25G5单抗识别的细胞是具有自我更新、高侵袭、高耐药性特征的肿瘤干细胞。体外功能研究发现,单抗25G5能显著抑制SNU-5胃癌细胞在无血清培养液中的成球生长,抑制率可达46.4%,也能显著地抑制SNU-5成球细胞(Sphere细胞)的侵袭,抑制率达58.4%。单抗25G5是一株能显著抑制SNU-5中肿瘤干细胞自我更新和侵袭能力的功能性抗人胃癌干细胞单抗。[结论]单克隆抗体25G5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。     

大肠癌细胞HCT-15肿瘤干细胞样细胞分离及成瘤性比较

目的:依据人大肠癌细胞HCT-15的表面标志物,分离其中的干细胞亚群。建立裸鼠体内原代大肠癌荷瘤模型,比较各亚群肿瘤体积和质量。方法:利用免疫磁珠分选技术,分离其中CD133/CD44干细胞亚群。分选得到CD133+CD44+、CD133+CD44-亚群分别接种于裸鼠体内,并观察肿瘤大小和质量。结果:CD133+CD44+和CD133+CD44-细胞亚群成功的从HCT-15细胞中分离出来。接种CD133+CD44+细胞的裸鼠形成的肿瘤体积［（2.76±0.22）cm3］和质量［（5.2±0.21）g］明显高于接种CD133+CD44-细胞裸鼠的肿瘤体积与质量［（1.56±0.34）cm3,（3.4±0.18）g］（P＜0.05）。结论:CD44阳性的大肠癌肿瘤干细胞成瘤能力明显高于CD44阴性的大肠癌肿瘤干细胞。     

人胆囊癌CD133+细胞亚群致瘤性的实验研究

目的:研究CD133在人胆囊癌细胞中的表达,初步探讨胆囊癌CD133+亚群的致瘤能力.方法:将人原代胆囊癌组织植入裸鼠皮下形成移植瘤,并同人原代胆囊癌组织分别制成单细胞悬液;FCM法检测CD133的表达情况,并分选出CD133+和CD133-亚群;对不同亚群细胞进行体外克隆形成实验和裸鼠体内移植瘤形成实验,免疫组织化学法验证移植瘤的组织表型.结果:FCM法检测显示,胆囊癌细胞中1.95%～3.24%的细胞CD133呈阳性表达;体外培养显示CD133+亚群比CD133-亚群具有更强的克隆球形成能力,在裸鼠体内也具有更强的肿瘤形成能力(P<0.05);免疫组织化学检测结果提示,胆囊癌CD133+细胞形成的移植瘤同人原代胆囊癌具有相同的组织表型,均表达CA19-9和CD44s.结论:人胆囊癌CD133+细胞亚群具有高致瘤性,其中可能富含有肿瘤干细胞.     

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.     

Immunosuppressive effects of (131)I-anti-CD45 antibody in unsensitized and donor antigen-presensitized H2-matched, minor antigen-mismatched murine transplant models.

Iodine-131-labeled anti-CD45 antibody has been added to conventional hematopoietic stem cell transplant preparative regimens to deliver targeted radiation to hematopoietic tissues, with the goal of decreasing relapse rates without increasing toxicity. However, higher radiation doses could be delivered to leukemia cells by antibody if the systemic therapy were decreased or eliminated. To examine the ability of (131)I-anti-CD45 antibody to provide sufficient immunosuppression for transplantation across allogeneic barriers, T-cell-depleted BALB.B marrow was transplanted into H2-compatible B6-Ly5(a) mice after (131)I-30F11 (rat antimurine CD45) antibody with or without varying dose levels of total body irradiation (TBI). Groups of five or six recipient mice per (131)I or TBI dose level per experiment were given tail vein injections of 100 microg of (131)I-labeled 30F11 antibody 4 days before marrow infusion, with or without TBI on day 0. Engraftment, defined as > or =50% donor B cells at 3 months posttransplant, was determined by two-color flow cytometric analysis of peripheral blood granulocytes, T cells, and B cells using antibodies specific for donor and host CD45 allotypes and for CD3. Donor engraftment of > or =80% recipient mice was achieved with either 8 Gy of TBI or 0.75 mCi of (131)I-30F11 antibody, which delivers an estimated 26 Gy to bone marrow. Subsequent experiments determined the dose of TBI alone or TBI plus 0.75 mCi of (131)I-30F11 antibody necessary for engraftment in recipient mice that had been presensitized to donor antigens before transplant, a setting requiring more stringent immunosuppression. Engraftment was seen in > or =80% of presensitized recipients surviving after 14-16 Gy of TBI or 12-14 Gy of TBI and 0.75 mCi of (131)I-30F11 antibody. However, only 28 of 69 (41%) presensitized mice receiving 10-16 Gy of TBI alone survived, presumably because of rejection of donor marrow and ablation of host hematopoiesis. In contrast, 29 of 35 (83%) presensitized mice receiving (131)I-30F11 antibody and 10-14 Gy of TBI survived, presumably because the additional immunosuppression provided by estimated radiation doses of 53 Gy to lymph nodes and 81 Gy to spleen from 0.75 mCi of (131)I-30F11 antibody permitted engraftment of donor marrow. These results suggest that targeted radiation delivered by (131)I-anti-CD45 antibody provides sufficient immunosuppression to replace an appreciable portion of the TBI dose used in matched sibling hematopoietic stem cell transplant.     

Two monoclonal antibodies selective for human mammary carcinoma

Mouse myeloma cells were fused with spleen cells from BALB/c mice immunized with the MCF-7 human mammary carcinoma cell line. Among hybridomas, two (3B18 and 15A8) were selected and cloned. Hybridoma 3B18 produces kappa-IgG1 antibodies that react with a cytoplasmic component of MCF-7 cells. In immunoperoxidase assays, 3B18 reacts with 27 of 31 specimens of human mammary carcinoma. It reacts most consistently with poorly differentiated and infiltrating ductal breast cancers, but it also reacts with isolated cells in 3 of 5 benign mammary pathological lesions with a variable distribution. The antibody does not react with normal mammary epithelium. It does not react with any normal human tissues, and it reacts with only one of 19 other cancers tested. Hybridoma 15A8 produces kappa-IgG1 antibodies that react with the surface membranes of the cells of two human breast cancer cell lines but not with a human fibroblast cell line. In immunoperoxidase assays, the antibody reacted with 28 out of 31 human mammary carcinomas. The antibody also reacts more weakly with normal human epithelial cells of breast, renal proximal tubule, skin, esophagus, and salivary gland, but no other normal tissue. The antibody was unreactive with 14 of 18 other malignant tissues tested. Since 3B18 and 15A8 detect antigens found predominantly in human mammary carcinomas and, possibly, distinguish overlapping categories of human mammary carcinomas, they may prove useful in determining the cellular lineage from which human mammary carcinomas arise, or they may have other clinical applications in breast cancer.     

Optimized protocols for generation of cord blood-derived cytokine-induced killer/natural killer cells

The efficacy of various combinations of stem cell factor (SCF), FLT3 ligand, interleukin (IL)-2, IL-7 and IL-15 to induce and expand cord blood-derived cytokine-induced killer (CIK) cells was investigated. There were three treatment groups: group A: SCF combined with IL-2, IL-7 and IL-15; group B: SCF, FLT3 ligand combined with IL-2, IL-7 and IL-15, and group C: IL-2, IL-7 and IL-15, the control group. Proliferation rates of CD3(+)CD56(+) CIK cells and CD3(-)CD56(+) natural killer (NK) cells were highest in group B; expansion of CIK cells increased 796.1 ± 278.5-fold, and that of NK cells increased 36.6 ± 3.5-fold. All expanded cord blood-derived CIK/NK cells showed cytotoxic activity against the K562 cell line. Interestingly, the cytotoxicity of group A was highest and significantly higher than that of other groups. These protocols might provide an alternative choice for CIK/NK cell expansion.     

Syngeneic monoclonal antibodies to B16 melanoma viral antigens

Four stable IgM monoclonal antibody-producing hybridomas were generated by fusing mouse myeloma cells with spleen lymphocytes from C57BL/6 mice hyperimmunized against the syngeneic B16 melanoma. All four monoclonal antibodies (R31/15, R37/4, R37/6, and R37/7), in common with polyclonal antiserum from immunized mice, recognized antigens on the same complex of related cell surface molecules specified by endogenous AKR-type murine leukemia virus, designated the B16-gp/70/80/85 antigen complex. Reactivity with this antigen complex was demonstrated by radioimmunoprecipitation. Specificity for viral Mr 70,000 glycoprotein-related antigens was indicated by absorption of antibody activity by endogenous AKR virus and by inhibition of antibody binding to B16 melanoma cells by monospecific antiserum to murine leukemia virus Mr 70,000 glycoprotein. Neither polyclonal nor monoclonal antibodies recognized antigens on fish, guinea pig, swine, or human melanoma cell lines. Polyclonal antiserum reacted with several other mouse melanomas and with certain mouse lymphoma lines induced by, or harboring, endogenous murine leukemia viruses, but the monoclonal antibodies were unreactive except for recognition of antigens on Harding-Passey mouse melanoma cells by antibody R37/4 and on RL male 1 mouse lymphoma cells by antibody R37/7. Only monoclonal R37/7 was cytotoxic for cultured B16 melanoma cells in an antibody- and complement-dependent assay with guinea pig complement, although all antibodies were cytotoxic with rabbit complement. In reflecting the predominant humoral immune response to the B16 melanoma detected in syngeneic mice during tumor growth, these monoclonal antibodies will permit experimental amplification of that response to help determine how that immunity influences tumor growth and metastatic dissemination.     

抗胰腺癌干细胞单克隆抗体的筛选和鉴定

目的：从抗胰腺癌干细胞单抗库中筛选、鉴定识别胰腺癌干细胞的功能性单抗,为胰腺癌干细胞靶向治疗提供候选抗体药物。方法：无血清悬浮培养及PKH26染色确定胰腺癌HPAC细胞系中肿瘤干细胞的存在。流式细胞术检测HPAC的干细胞标志物CD133在球体细胞中的阳性比例,检测20株杂交瘤单抗在HPAC亲本和球体细胞中的阳性表达。双色荧光标记流式细胞术检测CD133和单抗在HPAC亲本和球体细胞中的共表达比例;无血清悬浮培养法观察单抗15E9对HPAC成球细胞自我更新的影响。CCK一8法检测单抗15E9对HPAC细胞增殖和耐药的影响。结果：HPAC细胞能在无血清培养基中存活、增殖并形成细胞球,成球率为4．8％±0．6％。HPAC球体细胞中CD133’细胞的比例较亲本细胞提高至11．6倍。20株候选杂交瘤单抗中有3株单抗能识别HPAC球体细胞中CD133’细胞,其中单抗15E9共染比例为3．5％,并能显著抑制HPAC细胞的成球,抑制率达到30．4％。单抗15E9联合吉西他滨能显著抑制HPAC球体细胞的增殖,联合组和对照组Ic50分别为30．8nmol／L和58．1nmol／L。结论：本研究成功筛选出1株杂交瘤单抗可以识别胰腺癌干细胞,并且可识别CD133＋的胰腺癌干细胞;体外功能显示该抗体具有抑制HPAC干细胞的自我更新能力,抗体干预后显著降低HPAC耐药能力,可能是潜在的胰腺癌干细胞的靶向治疗抗体药物。     

Immunotherapeutic potential of B7-DC (PD-L2) cross-linking antibody in conferring antitumor immunity

A naturally occurring human antibody potentiates dendritic cell function on cross-linking B7-DC (PD-L2), supporting robust T-cell responses in vitro. Moreover, treatment of dendritic cells with B7-DC cross-linking antibody resulted in secretion of interleukin-12, suggesting a TH1 polarization of this response. Here we show an in vivo immunotherapeutic effect of this B7-DC cross-linking antibody using a poorly immunogenic B16 melanoma tumor model. Treatment of mice systemically with antibody at the time of tumor cell engraftment prevented tumor growth in a CD4 and CD8 T-cell-dependent manner. The protective effect of B7-DC cross-linking antibody treatment was independent of endogenous antibody responses. Tumor-specific CTL precursors could be isolated from lymph nodes draining the tumor site in animals treated with B7-DC cross-linking antibody, but not from those treated with isotype control antibodies. The elicited antitumor responses in vivo were specific and long-lasting. More strikingly, treatment of mice with B7-DC cross-linking antibody after the tumors were established in the lungs resulted in protection in a CD8-, perforin-, and granzyme B-dependent fashion. Depletion of natural killer cells did not block the effects of treatment with B7-DC cross-linking antibody. Together, these findings demonstrate that cross-linking B7-DC with the human IgM antibody sHIgM12 can induce a protective immune response against a weakly antigenic experimental tumor and therefore has potential as a novel immunotherapeutic approach for treating cancer.     

B7-H4 expression is elevated in human U251 glioma stem-like cells and is inducible in monocytes cultured with U251 stem-like cell conditioned medium

Previous studies indicated that B7-H4, the youngest B7 family, negatively regulates T cell-mediated immunity and is significantly overexpressed in many human tumors. Tumor stem cells are purported to play a role in tumor renewal and resistance to radiation and chemotherapy. However, the link between B7-H4 and tumor stem cells is unclear. In this study, we investigated B7-H4 expression in the medium of human glioma U251 cell cultures. Immunofluorescence results showed that U251 cells cultured in serum-free medium （supplemented with 2% B27, 20 ng/mL epidermal growth factor, 20 ng/mL basic fibroblast growth factor） maintained stem-like cell characteristics, including expression of stem cell marker CD133 and the neural progenitor cell markers nestin and SOX2. In contrast, U251 cells cultured in serum-containing medium highly expressed differentiation marker glial fibrillary acidic protein. Flow cytometry analysis showed serum-free medium-cultured U251 cells expressed higher intracellular B7-H4 than serum- containing medium-cultured U251 cells （24%-35% vs. 8%-11%, P 〈 0.001）. Immunofluorescence in purified monocytes from normal human peripheral blood mononuclear cells revealed moderate expression of BT-H4 after stimulation with conditioned medium from U251 cells cultured in serum-containing medium. Moreover, conditioned medium from U251 stem-like cells had a significant stimulation effect on B7-H4 expression compared with serum-containing conditioned medium （P 〈 0.01）. Negative costimulatory molecule B7-H4 was preferentially expressed in U251 stem-like cells, and conditioned medium from these cells more effectively induced monocytes to express BT-H4 than conditioned medium from U251 cells cultured in the presence of serum. Our results show that U251 stem-like cells may play a more crucial role in tumor immunoloregulation with high expression of B7-H4.