普奈洛尔对胃癌放疗敏感性影响及其机制的实验研究

目的:从体内实验探究普萘洛尔对胃癌放疗敏感性的作用。方法:使用胃癌细胞株SGC-7901和BALA/C-nunu裸鼠皮下移植瘤模型,利用β受体阻滞剂干预裸鼠,通过测量胃癌移植瘤重量和体积判断肿瘤生长情况,通过免疫组织化学法和Western blot法研究NF-κB、EGFR、COX-2和VEGF的表达。结果:在裸鼠体内实验发现,在放疗前给予普奈洛尔可以明显减小移植瘤的体积及重量,起到抑制肿瘤生长和促进肿瘤凋亡的作用。通过免疫组织化学染色和Western blot发现放疗前使用普奈洛尔较单独使用放射治疗,可以降低细胞及组织NF-κB表达,并下调其下游相关分子VEGF、EGFR和COX-2的表达,从而抑制胃癌细胞的增殖及抑制其侵袭转移的能力。而在单独使用相同剂量普奈洛尔进行干预未见上述变化。结论:通过β受体阻滞剂普奈洛尔可以加强细胞和组织对放射治疗的敏感性,从而阻断NF-κB表达,下调核转录因子下游相关分子VEGF、EGFR和COX-2的表达,抑制胃癌细胞的增殖及抑制其侵袭转移的能力。提示β受体阻滞剂可作为胃癌的放疗增敏剂,有抗增殖、促凋亡、抑制侵袭和转移能力,为提高胃癌放疗效果提供基础,为探索新的放疗增敏剂提供理论依据。     

腺病毒介导VEGF-siRNA对荷人骨肉瘤裸鼠移植瘤生长的影响

目的:观察腺病毒介导的VEGF-siRNA对荷人骨肉瘤细胞株MG63裸鼠移植瘤生长的影响。方法:将Ad-VEGF-siRNA感染MG63,用噻唑蓝(thiazolyl blue,MTT)法检测细胞体外增殖活力,反转录-聚合酶链反应(reverse transeription-poly-merase chain reaction,RT-PCR)法检测VEGF抑制效果。建立裸鼠移植瘤模型,定期瘤内注射Ad-VEGF-siRNA,观察裸鼠致瘤率、肿瘤体积、抑瘤率及免疫组化法检测肿瘤组织中bcl-2的表达。结果:感染Ad-VEGF-siRNA能明显抑制MG63细胞的生长,瘤灶内注射Ad-VEGF-siRNA后裸鼠移植瘤的质量和体积均显著低于对照组(P<0.01)。TUNEL染色显示肿瘤细胞凋亡增加,免疫组化结果提示肿瘤组织中bcl-2表达明显减少(P<0.01)。结论:Ad-VEGF-siRNA可有效而特异地阻断VEGF基因表达,抑制裸鼠移植瘤生长,促进肿瘤细胞的凋亡。     

特异性靶向Bcl-XL ShRNA抑制Lovo细胞移植瘤生长的实验研究

目的 探讨靶向Bcl-XL shRNA对人结肠癌Lovo细胞裸鼠移植瘤的生长抑制作用.方法 构建两个靶向Bcl-XL的shRNA质粒载体XL1、XL2和阴性对照质粒Neg,并将其转入人结肠癌Lovo细胞,分组种植建立人结肠癌裸鼠移植瘤模型.随后观察各组裸鼠的肿瘤生长情况.第8周裸鼠处死,HE染色观察肿瘤细胞的形态,免疫组化方法检测Bcl-XL蛋白的表达,TUNEL法检测肿瘤细胞的凋亡情况.结果 第8周XL1、XL2实验组裸鼠移植瘤的体积和质量与空白对照组相比均有显著缩小(P<0.05),抑制率约50%.与空白对照组相比,XL1、XL2组移植瘤的Bcl-XL表达均有显著下调,肿瘤细胞凋亡指数均有显著升高(P<0.05).阴性对照组的上述指标与空白对照组相比差异均无统计学意义.结论 靶向Bcl-XL shRNA能够抑制人结肠癌Lovo细胞裸鼠移植瘤的生长,可能机制为促进肿瘤细胞凋亡.     

EGCG通过下调Bcl-2、NF-κB(p65)表达,活化Caspase-3诱导人胃癌细胞凋亡的实验研究

目的:观察表没食子儿茶素没食子酸酯(Epigallocatechin-3-gallate, EGCG)对人胃癌SGC7901细胞裸鼠移植瘤生长的抑制作用,探讨EGCG诱导移植瘤细胞凋亡作用的分子机制. 方法:建立人胃腺癌(SGC7901)细胞裸鼠异种移植瘤模型,用不同剂量的EGCG进行治疗,并设对照;采用TUNEL法检测肿瘤组织中细胞凋亡情况,Western blot法检测肿瘤组织凋亡相关基因NF-κB(p65)、Bcl-2、Bax、Caspase-3蛋白表达情况. 结果:EGCG对移植瘤生长有明显抑制作用;TUNEL法发现EGCG导致移植瘤内细胞发生凋亡;Western blot分析表明EGCG能下调NF-κB(p65)蛋白的表达,促使Bax/Bcl-2蛋白表达的比值增高,并且可以促进Caspase-3的活化. 结论:EGCG对人胃癌细胞裸鼠移植瘤有明显的抑制作用,并能诱导移植瘤细胞凋亡.其机制可能与通过NF-κB(p65)的下调,促使Bax/Bcl-2比值增高,进而导致Caspase-3的活化而诱导细胞发生凋亡相关.     

5-脂氧合酶活化蛋白抑制剂MK886治疗裸鼠人结肠癌移植瘤的实验

 目的观察5-脂氧合酶活化蛋白(FLAP)抑制剂MK886对裸鼠人结肠癌移植瘤的治疗作用,并探讨其抗肿瘤的可能机制。方法以HT-29人结肠癌细胞制备裸鼠人结肠癌移植瘤模型,15只荷瘤裸鼠随机分为三组,治疗组以MK886溶解在二甲基亚砜中投药,两对照组分别给以二甲基亚砜及不作任何治疗。治疗期间观察肿瘤生长情况,治疗结束后处死裸鼠并取瘤,测量肿瘤体积重量,用免疫组化方法检测肿瘤微血管密度,用TUNEL法检测肿瘤细胞凋亡情况。结果15只裸鼠全部成瘤,且实验过程中无一裸鼠死亡;通过测量瘤体积、瘤重结果显示,MK886可抑制人结肠癌裸鼠皮下移植瘤的生长;实验还证实MK886对人结肠癌裸鼠皮下移植瘤具有诱导肿瘤细胞凋亡及抗血管生成作用。结论MK886对于裸鼠人结肠癌移植瘤具有明显的治疗效果,MK886可能通过诱导肿瘤细胞凋亡、抑制肿瘤微血管形成等机制控制人结肠癌的生长。     

西妥昔单抗联合奥沙利铂治疗头颈部鳞癌HN5裸鼠移植瘤的实验研究

目的:观察阻断EGFR的西妥昔单克隆抗体(cetuximab,C225)是否能提高奥沙利铂(OXA)对头颈部鳞癌细胞株HN5移植瘤的抗瘤效应。方法:建立裸鼠移植瘤模型50只,当裸鼠右大腿的肿瘤直径达到8.0mm(7.6~8.3mm)时开始实验。实验共分5组(每组10只),分别为对照组、单用C225组、单用OXA组、C225 OXA(6h)组和C225 OXA(24h)组。观察指标为肿瘤生长延迟时间(肿瘤从8.0mm生长至12.0mm所需时间)和肿瘤治愈的情况。结果:除C225 OXA(6h)组中有1只荷瘤裸鼠在治疗过程中死亡外,其余荷瘤裸鼠有8只肿瘤消失,其中单用C225组和单用OXA组各1只,C225 OXA(6h)组有4只,C225 OXA(24h)组有2只。余下41只的裸鼠肿瘤生长情况为:单用C225组和单用OXA组的绝对延迟时间分别为(21.4±8.2)天和(2.7±2.4)天,而C225 OXA(6h)组和C225 OXA(24h)组的绝对延迟时间则分别为(32.5±8.1)天和(30.0±10.4)天,其标准化的延迟时间分别为(11.1±8.1)天和(8.6±10.4)天,增益因子分别为4.11和3.19。结论:C225能提高OXA对头颈部鳞癌细胞株HN5移植瘤的抗瘤效应。     

E1A基因对裸鼠移植瘤生长抑制及其初步作用机制的实验研究

目的：探讨E1A基因对人宫颈癌细胞裸鼠移植瘤生长的抑制作用及其相关作用机制。方法：通过裸鼠移植瘤实验,观察E1A基因对人宫颈癌细胞裸鼠移植瘤生长的的抑制作用。采用免疫组织化学染色检测E1A基因对肿瘤细胞凋亡及Survivin基因和Caspase-3基因表达的影响。结果：裸鼠移植瘤实验结果显示：Hela-E1A细胞形成的肿瘤较Hela和Hela-vect的出瘤时间晚,生长慢,瘤重小,抑瘤率分别为83.42%和84.74%。免疫组织化学染色显示：E1A基因组细胞凋亡数量较Hela和Hela-vect组明显增多,Caspase-3基因（凋亡促进因子）呈高表达,Survivin基因（调亡抑制因子）的表达明显降低。结论：E1A基因能够明显抑制人宫颈癌细胞裸鼠移植瘤的生长,该作用可能与E1A基因激活Caspase-3基因和降低Survivin基因的表达有关。     

靶向p65基因的miRNA对人三阴性乳腺癌细胞裸鼠移植瘤生长的抑制作用

背景与目的:三阴性乳腺癌(triple-negative breast cancer,TNBC)是乳腺癌中预后较差的一个亚型,如何防治TNBC的快速生长成为近几年临床研究的热点之一。NF-κB信号通路在肿瘤发生、发展的各个环节中扮演重要角色,有望成为肿瘤基因治疗新的方向。本研究通过建立人TNBC裸鼠移植瘤模型,观察靶向沉默NF-κB p65亚基的微小RNA(microRNA,miRNA)治疗对TNBC裸鼠移植瘤生长及凋亡的影响,并初步探讨其可能的作用机制。方法:建立人TNBC细胞株MDA-MB-231裸鼠移植瘤动物模型,瘤旁注射p65miRNA质粒(p65miRNA组),同时以注射Neg-miRNA质粒和PBS作为Neg-miRNA对照组和空白对照组。监测肿瘤生长变化,测量肿瘤质量。流式细胞术(flow cytometry,FCM)检测肿瘤细胞凋亡的变化。免疫组化法检测肿瘤组织中p65的表达。Western blot法检测肿瘤组织中Bcl-2和Bax蛋白的表达水平。结果:经p65miRNA处理后,裸鼠肿瘤的生长受到明显抑制。FCM结果表明,p65miRNA组肿瘤细胞凋亡率为(31.08±3.52)%,明显高于Neg-miRNA组(5.76±1.02)%和空白对照组(4.29±0.86)%(P<0.05)。此外,p65miRNA组裸鼠肿瘤组织p65和Bcl-2的蛋白表达明显下调,Bax的蛋白表达显著上调。结论:p65miRNA能抑制人TNBC裸鼠皮下移植瘤的生长,且在体内可诱导肿瘤细胞凋亡。     

Survivin基因RNAi对子宫颈癌裸鼠移植瘤生长与凋亡的影响

目的：观察survivin基因RNAi对宫颈癌裸鼠移植瘤生长与凋亡的影响。方法：随机将BALB/c裸鼠分4组,分别注射转染携survivin RNAi重组质粒的HeLas2细胞、转染阴性对照质粒细胞HeLaNC、转染空质粒细胞HeLaU6 neo及宫颈癌HeLa细胞,建立人宫颈癌裸鼠皮下移植瘤模型。观察survivin RNAi对人宫颈癌裸鼠皮下移植瘤生长的影响;免疫组化法检测移植瘤组织中survivin蛋白的表达和微血管密度（MVD）,HE染色及TUNEL染色观察survivin RNAi对人宫颈癌裸鼠皮下移植瘤凋亡的影响。结果：成功建立人宫颈癌裸鼠皮下移植瘤模型, HeLas2组裸鼠瘤重明显小于其他3组（P<0.05）;肿瘤生长抑制率为67.9%。免疫组化结果显示,HeLas2组裸鼠移植瘤组织中survivin蛋白表达显著下降; MVD值也显著降低（P<0.05）;HE染色、TUNEL染色结果显示,HeLas2组裸鼠移植瘤组织细胞凋亡明显增多（P<0.05）,AI值达(22.73±137)%。结论：Survivin基因RNAi可通过下调移植瘤组织survivin蛋白表达和降低其MVD抑制移植瘤生长并促进其凋亡。     

多西紫杉醇联合曲格列酮对人前列腺癌裸鼠移植瘤的抑制作用

目的:探讨多西紫杉醇联合曲格列酮(troglitazone,TGZ)对人前列腺癌裸鼠移植瘤的抑制作用,并初步探索其作用机制.方法:建立人前列腺癌裸鼠移植瘤模型,观察多西紫杉醇联合TGZ对移植瘤生长的抑制作用,FCM法检测移植瘤细胞的凋亡率,免疫组织化学法检测移植瘤组织中bcl-2和bax蛋白的表达情况.结果:与对照组比较, 多西紫杉醇联合TGZ可明显抑制人前列腺癌裸鼠移植瘤的生长,肿瘤体积和质量明显下降,细胞凋亡率明显上升;免疫组织化学法检测结果显示,移植瘤组织中bax蛋白的表达明显增强,bcl-2蛋白的表达明显减弱.结论:多西紫杉醇联合TGZ对前列腺癌有一定的抑制作用,其作用机制可能是通过上调促凋亡蛋白bax的表达及下调抗凋亡蛋白bcl-2的表达,导致肿瘤细胞加速凋亡而实现的.     

Antitumor activity of ZD6474, a vascular endothelial growth factor receptor tyrosine kinase inhibitor, in human cancer cells with acquired resistance to antiepidermal growth factor receptor therapy.

PURPOSE: The epidermal growth factor receptor (EGFR) autocrine signaling pathway is involved in cancer development and progression. EGFR inhibitors such as C225 (cetuximab), a chimeric human-mouse anti-EGFR monoclonal antibody, and ZD1839 (gefitinib), a small molecule EGFR-selective tyrosine kinase inhibitor, are in advanced clinical development. The potential emergence of cancer cell resistance in EGFR-expressing cancers treated with EGFR inhibitors could determine lack of activity of these drugs in some cancer patients. Vascular endothelial growth factor (VEGF) is secreted by cancer cells and plays a key role in the regulation of tumor-induced endothelial cell proliferation and permeability. ZD6474 is a small molecule VEGF flk-1/KDR (VEGFR-2) tyrosine kinase inhibitor that also demonstrates inhibitory activity against EGFR tyrosine kinase. EXPERIMENTAL DESIGN: The antitumor activity of ZD1839, C225, and ZD6474 was tested in athymic mice bearing human GEO colon cancer xenografts. GEO cell lines resistant to EGFR inhibitors were established from GEO xenografts growing in mice treated chronically with ZD1839 or C225. Expression of EGFR was evaluated by flow cytometry. Expression of various proteins involved in intracellular cell signaling was assessed by Western blotting. Tumor growth data were evaluated for statistical significance using the Student's t test. All Ps were two-sided. RESULTS: Although chronic administration of optimal doses of C225 or ZD1839 efficiently blocked GEO tumor growth in the majority of mice, tumors slowly started to grow within 80-90 days, despite continuous treatment. In contrast, continuous treatment of mice bearing established GEO xenografts with ZD6474 resulted in efficient tumor growth inhibition for the entire duration of dosing (up to 150 days). ZD6474 activity was also determined in mice pretreated with ZD1839 or C225. When GEO growth was apparent after 4 weeks of treatment with EGFR inhibitors, mice were either re-treated with EGFR inhibitors or treated with ZD6474. GEO tumor growth was blocked only in mice treated with ZD6474, whereas tumor progression was observed in mice re-treated with C225 or ZD1839. GEO tumors growing during treatment with C225 or with ZD1839 were established as cell lines (GEO-C225-RES and GEO-ZD1839-RES, respectively). Cell membrane-associated EGFR expression was only slightly reduced in these cell lines compared with parental GEO cells. Western blotting revealed no major change in the expression of the EGFR ligand transforming growth factor alpha of bcl-2, bcl-xL, p53, p27, MDM-2, akt, activated phospho-akt, or mitogen-activated protein kinase. However, both GEO-C225-RES and GEO-ZD1839-RES cells exhibited a 5-10-fold increase in activated phospho-mitogen-activated protein kinase and in the expression of cyclooxygenase-2 and of VEGF compared with GEO cells. GEO-C225-RES and GEO-ZD1839-RES growth as xenografts in nude mice was not significantly affected by treatment with either C225 or ZD1839 but was efficiently inhibited by ZD6474. CONCLUSIONS: Long-term treatment of GEO xenografts with selective EGFR inhibitors results in the development of EGFR inhibitor-resistant cancer cells. Growth of EGFR inhibitor-resistant tumors can be inhibited by ZD6474. These data indicate that inhibition of VEGF signaling has potential as an anticancer strategy, even in tumors that are resistant to EGF inhibitors.     

CXCL12受体抑制剂调控三阴性乳腺癌放射治疗的敏感性

目的 探讨趋化因子12（CXCL12）受体CXCR4抑制剂AMD3100对人乳腺癌MDA-MB 231细胞裸鼠移植瘤的放射增敏效应及其作用机制。方法 建立人乳腺癌裸鼠移植瘤模型,并随机分为4组：对照组、AMD3100处理组、放射治疗组和联合治疗组（AMD3100+放疗）;称量肿瘤的重量并测量移植瘤的体积,计算放射增敏比,绘制肿瘤生长曲线;实时荧光定量PCR（QPCR）检测CXCR4和表皮生长因子受体（EGFR）基因表达;蛋白质印迹法检测CXCR4、EGFR和基质金属蛋白酶-9（MMP-9）蛋白表达。结果 经统计CXCR4抑制剂AMD3100的放射增敏比为1:45。QPCR结果显示,与对照组比较,CXCR4和EGFR基因的相对表达量在AMD3100处理组、放射治疗组及联合治疗组分别下调60％、45％、82％和56％、48％、73％,差异有统计学意义（P＜0.05）。单纯AMD3100治疗或者放射治疗均能使CXCR4、EGFR表达下调（P＜0.05）,联合治疗较单纯AMD3100治疗和放疗更能显著地抑制CXCR4和EGFR的表达（P＜0.05）。Western blotting结果显示,与对照组比较,CXCR4、EGFR及MMP-9在AMD3100处理组、放射治疗组及联合治疗组中的蛋白相对表达量均下调（P＜0.05）。AMD3100与放疗均可抑制CXCR4、EGFR及MMP-9的表达,两者联用较单一治疗的效果更加显著（P＜0.05）。     

Insulin-like growth factor receptor as a therapeutic target in head and neck cancer.

PURPOSE: Insulin-like growth factor type I receptor (IGF-IR) plays critical roles in epithelial cancer cell development, proliferation, motility, and survival, and new therapeutic agents targeting IGF-IR are in development. Another receptor tyrosine kinase, the epidermal growth factor receptor (EGFR), is an established therapeutic target in head and neck cancer and IGF-IR/EGFR heterodimerization has been reported in other epithelial cancers. The present study was undertaken to determine the effects of anti-IGF-IR therapeutic targeting on cell signaling and cancer cell phenotypes in squamous cell carcinomas of the head and neck (SCCHN). EXPERIMENTAL DESIGN: The therapeutic efficacy of the human anti-IGF-IR antibody IMC-A12 alone and in combination with the EGFR blocking antibody cetuximab (C225) was tested in SCCHN cell lines and in tumor xenografts. RESULTS: IGF-IR was overexpressed in human head and neck cancer cell lines and tumors. Pretreatment of serum-starved 183A or TU159 SCCHN cell lines with A12 (10 microg/mL) blocked IGF-stimulated activation of IGF-IR, insulin receptor substrate (IRS)-1 and IRS-2, mitogen-activated protein kinase, and phosphatidylinositol 3-kinase. A12 induced G(0)-G(1) cell cycle arrest and blocked cell growth, motility, and anchorage-independent growth. Stimulation of head and neck cancer cells with either IGF or EGF resulted in IGF-IR and EGFR heterodimerization, but only IGF caused activating phosphorylation of both receptors. Combined treatment with A12 and the EGFR blocking antibody C225 was more effective at reducing cell proliferation and migration than either agent alone. Finally, TU159 tongue cancer cell xenografts grown in athymic nude mice were treated thrice weekly for 4 weeks with vehicle, A12 (40 mg/kg i.p.), C225 (40 mg/kg i.p.), or both agents (n=8 mice per group; 2 tumors per mouse). Linear regression slope analysis showed significant differences in median tumor volume over time between all three treatment groups and the control group. Complete regression was seen in 31% (A12), 31% (C225), and 44% (A12 + C225) of tumors. CONCLUSION: Here we found the overexpression of IGF-IR, the functional heterodimerization of IGF-IR and EGFR, and effective therapeutic targeting of these receptors in human head and neck cancer xenografts.     

Claudin-1蛋白在胃癌组织和细胞中的表达及促进其表达后对癌细胞增殖、侵袭和迁移的影响

目的:研究紧密连接跨膜蛋白(Claudin-1)在胃癌组织中的表达及其对胃癌细胞生物学行为及裸鼠皮下成瘤能力的影响.方法:收集50例胃癌患者的癌组织及其癌旁组织,采用RT-qPCR和免疫组化检测Claudin-1的表达;RT-qPCR和Western Blot检测Claudin-1在人胃癌细胞株MKN45、SGC790...     

Antitumor activity of combined treatment of human cancer cells with ionizing radiation and anti-epidermal growth factor receptor monoclonal antibody C225 plus type I protein kinase A antisense oligonucleotide.

Recent studies have suggested that selective inhibition of mitogenic pathways may improve the antitumor activity of ionizing radiation. The epidermal growth factor receptor (EGFR) is overexpressed and is involved in autocrine growth control in the majority of human carcinomas. Protein kinase A type I (PKAI) plays a key role in neoplastic transformation and is overexpressed in cancer cells in which an EGFR autocrine pathway is activated. We used two specific inhibitors of EGFR and PKAI that are under clinical evaluation in cancer patients: C225, an anti-EGFR chimeric human-mouse monoclonal antibody (MAb); and a mixed-backbone antisense oligonucleotide targeting the PKAI RIalpha subunit (PKAI AS). We tested in human colon cancer (GEO) and ovarian cancer (OVCAR-3) cell lines the antiproliferative activity of MAb C225 and/or PKAI AS in combination with ionizing radiation. In vivo antitumor activity was evaluated in nude mice bearing established GEO xenografts. Dose-dependent inhibition of soft agar growth was observed in both cancer cell lines with ionizing radiation, C225, or PKAI AS oligonucleotide. A cooperative antiproliferative effect was obtained when cancer cells were treated with ionizing radiation followed by MAb C225 or PKAI AS oligonucleotide. This effect was observed at all doses tested in both GEO and OVCAR-3 cancer cell lines. A combination of the three treatments at the lowest doses produced an even greater effect than that observed when two modalities were combined. Treatment of mice bearing established human GEO colon cancer xenografts with radiotherapy (RT), MAb C225, or PKAI AS oligonucleotide produced dose-dependent tumor growth inhibition that was reversible upon treatment cessation. A potentiation of the antitumor activity was observed in all mice treated with RT in combination with MAb C225 or PKAI AS oligonucleotide. Long-term GEO tumor growth regression was obtained following treatment with ionizing radiation in combination with MAb C225 plus PKAI AS oligonucleotide, which produced a significant improvement in survival compared with controls (P < 0.001), the RT-treated group (P < 0.001), or the group treated with MAb C225 plus PKAI AS oligonucleotide (P < 0.001). All mice of the RT + MAb C225 + PKAI AS group were alive 26 weeks after tumor cell injection. Furthermore, 50% of mice in this group were alive and tumor-free after 35 weeks. This study provides a rationale for evaluating in cancer patients the combination of ionizing radiation and selective drugs that block EGFR and PKAI pathways.     

125I seed irradiation induces up-regulation of the genes associated with apoptosis and cell cycle arrest and inhibits growth of gastric cancer xenografts

ABSTRACT: BACKGROUND: Iodine 125 (125I) seed irradiation can be used as an important supplementary treatment for unresectable advanced gastric cancer. Here, we aim to comprehensively elucidate the biological effects induced by 125I seed irradiation in human gastric cancer xenograft model by using global expression and DNA methylation analyses. METHODS: The 24 mice bearing NCI-N87 gastric cancer xenografts were randomly separated into 2 groups: sham seeds (O mCi) were implanted into the control group (n=24); 125l seeds (0.9 mCi) were implanted into the treatment group (n=24). The mitotic index and apoptotic index were evaluated by quantitative morphometric analysis of the expression of proliferating cell nuclear antigen (PCNA) and in situ terminal transferase-mediated fluorescein deoxy- UTP nick end labelling (TUNEL), respectively. Global gene expression changes induced by 125I seed irradiation were analyzed by using Nimblegen Human gene expression array. DNA methylation profile in the tumors from control group was investigated with methylated DNA immunoprecipitation (MeDIP) and Nimblegen CpG promoter microarrays. The changes in the methylation status of selected genes was further investigated by using MeDIP-PCR. RESULTS: 125I seed irradiation suppresses the growth of gastric cancer xenografts in nude mice. PCNA staining and tissue TUNEL assays showed that both inhibition of cell proliferation and induction of apoptosis contribute to the 125I-induced tumor suppression in nude mouse model. Gene expression profiles revealed that the expression levels of several hundred genes, many of which are associated with apoptosis or cell cycle arrest, including BMF, MAPK8, BNIP3, RFWD3, CDKN2B and WNT9A, were upregulated following 125I seed irradiation. Furthermore, the up-regulation of some of these genes, such as BNIP3 and WNT9A, was found to be associated with irradiation-induced DNA demethylation. CONCLUSIONS: This study revealed that 125I seed irradiation could significantly induce the up-regulation of apoptosis- and cell cycle-related genes in human gastric cancer xenografts. And some of the up-regulation might be attributed to 125I-irradiation induced demethylation in gene promoter regions. Collectively, these findings provided evidence for the efficacy of this modality for the treatment of gastric cancer.     

携带p16基因增殖缺陷型腺病毒对胃癌细胞皮下移植瘤的治疗作用

诱导免疫原性肿瘤细胞死亡是抗肿瘤化疗药物的目标之一,该作用可以通过免疫系统的“旁观者效应”根除对化疗药物抵抗的肿瘤细胞和肿瘤干细胞。蒽环类化疗药物(anthracyclin)在激发机体免疫原性的抗肿瘤反应方面具有显著的效应,但DNA损伤类化疗药物如依托泊苷(etoposide)和丝裂霉素C(mitomycin C)则不能有效地诱导免疫原性的细胞死亡。蒽环类化疗药物是如何使机体免疫系统能够识别肿瘤细胞,继而激发机体抗肿瘤效应呢?该研究的结果表明,蒽环类化疗药物能够快速诱导促凋亡的钙网蛋白(calreticulin,CRT)从胞质转位到胞膜,从而被树突状细胞表…     

单克隆抗体CH12抑制头颈部鳞状细胞癌裸鼠种植瘤的生长

目的:观察嵌合型单克隆抗体CH12对头颈部鳞状细胞癌(head and neck squamous cell carcinomas,HNSCC)裸鼠种植瘤生长的抑制作用,为进一步研究CH12单抗在肿瘤治疗中的作用提供参考数据。方法:Western blotting检测5种HNSCC细胞系A253、CAL27、Detroit 562、FaDu和RPMI 2650中表皮生长因子受体(epidermal growth factor receptor,EGFR)的表达,流式细胞术检测CH12单抗同这5种细胞系的结合能力。皮下接种CAL27和A253细胞,建立HNSCC裸鼠种植瘤模型。模型鼠腹腔注射CH12单抗,以PBS作为阴性对照,观察肿瘤生长情况,绘制肿瘤生长曲线。结果:EGFR在CAL27、A253、FaDu及Detroit 562细胞中均有不同程度的表达,其中CAL27细胞中EGFR的表达水平最高,A253细胞次之。CH12单抗与5种HNSCC细胞系的结合能力由高到低依次为CAL27、FaDu、A253、Detroit 562和RPMI 265细胞。CH12单抗对CAL27和A253细胞裸鼠种植瘤的生长均有显著抑制作用,抑瘤率分别为56.8%(P=0.022)和59.7%(P=0.015)。结论:单克隆抗体CH12对EGFR高表达的HNSCC细胞种植瘤的生长具有明显的抑制作用。     

Antitumor effects of ZD6474, a small molecule vascular endothelial growth factor receptor tyrosine kinase inhibitor, with additional activity against epidermal growth factor receptor tyrosine kinase.

PURPOSE: Vascular endothelial growth factor (VEGF) is a major mitogen for endothelial cells and enhances vascular permeability. Enhanced VEGF secretion is found in human cancers and correlates with increased tumor neovascularization. ZD6474 is a p.o. bioavailable, VEGF flk-1/KDR receptor (VEGFR-2) tyrosine kinase inhibitor with antitumor activity in many human cancer xenografts and is currently in Phase I clinical development. EXPERIMENTAL DESIGN: We tested the effects of ZD6474 on EGFR phosphorylation in cell expressing functional epidermal growth factor receptor (EGFR) and the antiproliferative and the proapoptotic activity of ZD6474 alone or in combination taxanes in human cancer cell lines with functional EGFR but lacking VEGFR-2. The antitumor activity of this drug was also tested in nude mice bearing established GEO colon cancer xenografts. RESULTS: ZD6474 causes a dose-dependent inhibition of EGFR phosphorylation in mouse NIH-EGFR fibroblasts and human MCF-10A ras breast cancer cells, two cell lines that overexpress the human EGFR. ZD6474 treatment resulted in a dose-dependent inhibition of soft agar growth in seven human cell lines (breast, colon, gastric, and ovarian) with functional EGFR but lacking VEGFR-2. A dose-dependent supra-additive effect in growth inhibition and in apoptosis in vitro was observed by the combined treatment with ZD6474 and paclitaxel or docetaxel. ZD6474 treatment of nude mice bearing palpable GEO colon cancer xenografts (which are sensitive to inhibition of EGFR signaling) induced dose-dependent tumor growth inhibition. Immunohistochemical analysis revealed a significant dose-dependent reduction of neoangiogenesis. The antitumor activity of ZD6474 in GEO tumor xenografts was also found to be enhanced when combined with paclitaxel. Tumor regression was observed in all mice after treatment with ZD6474 plus paclitaxel, and it was accompanied by a significant potentiation in inhibition of angiogenesis. Six of 20 mice had no histological evidence of tumors after treatment with ZD6474 plus paclitaxel. CONCLUSIONS: This study suggests that in addition to inhibiting endothelial cell proliferation by blocking VEGF-induced signaling, ZD6474 may also be able to inhibit cancer cell growth by blocking EGFR autocrine signaling. These results provide also a rationale for the clinical evaluation of ZD6474 combined with taxanes in cancer patients.