阻断MDR1基因表达逆转结肠癌LoVo/5-Fu敏感性的研究

目的探讨沉默多药耐药基因MDR1逆转大肠癌耐药细胞株LoVo/5-Fu细胞对5-Fu的耐药性。方法实验分为3组,转染组(干扰质粒转染人大肠癌耐药细胞株LoVo/5-Fu细胞)、对照质粒组(转染无关质粒)和未转染对照组。构建靶向MDR1的短发夹RNA(shRNA-MDR1)重组质粒后,转染LoVo/5-Fu细胞,实时荧光定量PCR检测靶细胞MDR1基因表达抑制效果,MTT法检测LoVo/5-Fu细胞对5-Fu的敏感性,流式细胞仪检测细胞周期及细胞凋亡情况。平板克隆形成试验检测细胞克隆形成能力,免疫印迹法检测caspase-3及P-gp蛋白表达。结果与未转染组相比,转染组细胞MDR1 mRNA表达明显下调(P<0.05);细胞对5-Fu的IC50及RI显著降低(P<0.05),敏感性的相对逆转率为71.2%;细胞克隆形成率明显下降;G1期细胞数增加8.59%,S期的细胞数减少8.9%,G2/M期细胞数减少3.5%;细胞凋亡率增加9.2%(P值均<0.01)。caspase-3表达增高,P-gp蛋白降低。结论 shRNAMDR1可抑制大肠癌耐药细胞LoVo/5-Fu中MDR1的表达,从而改善了大肠癌耐药细胞对5-Fu的敏感性。     

转染肿瘤坏死因子-α及MDR1反义RNA逆转乳腺癌多药耐药的研究

目的：转染肿瘤坏死因子-α(TNF-α)cDNA和多药耐药基因(MDR1)的反义RNA到乳腺癌耐药细胞株MCF-7/ADR中进行表达，并观察它们在乳腺癌耐药逆转中的作用。 方法：应用RT-PCR和DNA重组技术构建反义绿色荧光蛋白pEGFP-MDR1融合蛋白表达载体和红色荧光蛋白pDsRed2-TNF-α融合蛋白表达载体，分别和同时导入乳腺癌耐药细胞株MCF-7/ADR中进行表达，检测转染前后细胞的生长曲线、细胞凋亡程度、MDR1-mRNA和P糖蛋白（P-gp）表达情况及对ADR敏感性的变化。 结果：转染后的细胞生长明显减慢，凋亡率显著增加，MDR1-mRNA和P糖蛋白（P-gp）表达明显降低，对ADR的耐药性明显下降，敏感性增加。 结论：联合运用不同的逆转耐药机制，将TNF-α cDNA及MDR1反义RNA分别或同时导入乳腺癌耐药细胞中，能有效达到逆转耐药的目的。     

骨软组织肉瘤中耐药相关蛋白表达及与化疗耐药的相关性

目的： 探讨4种耐药相关蛋白－P-糖蛋白（P-gp）、谷胱甘肽S-转移酶-π（GST-π）、肺耐药蛋白 (LRP)和多药耐药相关蛋白（MRP）在骨肉瘤细胞株Saos2和U2OS以及34例骨软组织肉瘤的表达及与化疗耐药的关系。 方法： 应用流式细胞术（FCM）检测蛋白表达；MTT法评估化疗耐药。 结果： Saos2细胞耐药相关蛋白的表达低于U2OS，阿霉素（ADM）、顺铂（DDP）、5-氟脲嘧啶（5-Fu）、丝裂霉素（MMC）、氮烯咪胺(DTIC) 和长春新碱（VCR）的敏感性高于U2OS。两细胞株经1/5半数抑制浓度（IC50）的ADM和 DDP分别处理 24 h 后，GST-π增幅达33％-43％。34例患者对ADM、DDP、5-Fu、MMC、DTIC、VCR和MTX的不敏感率分别为41.18％、17.65％、47.06％、50.00％、76.47％、61.76％和52.94％。肿瘤组织P-gp、GST-π、LRP和MRP表达分别为1.54、2.58、1.91和1.86。相关分析显示，P-gp表达与ADM耐药呈正相关(r=0.485，P<0.01)，GST-π表达与ADM、DDP、5-Fu、MMC耐药呈正相关(r分别为0.402、0.458 、0.364和0.500，P值分别为<0.05、<0.01、<0.05和<0.01)。耐药相关蛋白在不同性别、不同年龄、不同病理类型、不同肿瘤大小患者间的表达差异均无显著（P＞0.05）。经术前化疗的患者GST-π表达显著升高，且随访复发患者术前GST-π表达显著高于无复发患者(P<0.05)。 结论： 骨软组织肉瘤患者耐药相关蛋白表达及化疗敏感性存在显著个体差异。化疗可引起GST-π表达上调。原发GST-π高表达是骨软组织肉瘤耐药的主要机制并与预后有关。     

转染肿瘤坏死因子-α及MDR1反义RNA逆转乳腺癌多药耐药的研究

目的:转染肿瘤坏死因子-α(TNF-α)cDNA和多药耐药基因(MDR1)的反义RNA到乳腺癌耐药细胞株MCF-7/ADR中进行表达,并观察它们在乳腺癌耐药逆转中的作用.方法:应用RT-PCR和DNA重组技术构建反义绿色荧光蛋白pEGFP-MDR1融合蛋白表达载体和红色荧光蛋白pDsRed2-TNF-α融合蛋白表达载体,分别和同时导入乳腺癌耐药细胞株MCF-7/ADR中进行表达,检测转染前后细胞的生长曲线、细胞凋亡程度、MDR1-mRNA和P糖蛋白(P-gp)表达情况及对ADR敏感性的变化.结果:转染后的细胞生长明显减慢,凋亡率显著增加,MDR1-mRNA和P糖蛋白(P-gp)表达明显降低,对ADR的耐药性明显下降,敏感性增加.结论:联合运用不同的逆转耐药机制,将TNF-αcDNA及MDR1反义RNA分别或同时导入乳腺癌耐药细胞中,能有效达到逆转耐药的目的.     

HSP90靶向抑制剂P7与多西紫杉醇联用对三阴性乳腺癌细胞的协同抗肿瘤作用

目的探讨双功能小分子多肽LPLTPLP(P7)和化疗药物多西紫杉醇(DTX)联用对三阴性乳腺癌细胞系MDA-MB-231的影响。方法多肽P7与DTX两药联合处理三阴性乳腺癌细胞系MDA-MB-231 48 h后,用SRB法检测细胞存活;用等效图解法分析其作用;用流式细胞计量术检测多肽P7、化疗药DTX及两药联用后MDA-MB-231细胞凋亡率;用蛋白免疫印迹技术检测多肽P7、化疗药DTX及两药联用后MDA-MB-231细胞凋亡相关蛋白的表达。结果 P7与DTX对细胞存活具有协同作用;联合用药组细胞凋亡率为60.6%,是DTX单药组凋亡率(34.5%)的1.8倍;P7与DTX联合用药干预48 h后,凋亡相关蛋白Bcl-2与Bax表达量的比值显著下调。结论P7协同化疗药物DTX能显著提高细胞的凋亡率,其机制可能与两药联合后调控促凋亡蛋白Bax和凋亡蛋白Bcl-2表达相关。     

c-Met对三阴性乳腺癌细胞增殖及阿霉素耐药性的影响

目的:研究c-Met对三阴性乳腺癌细胞株MDA-MB-231活力及对阿霉素耐药性的影响。方法:构建阿霉素耐药的MDA-MB-231/ADR细胞系,实时荧光定量PCR及Western blotting技术检测不同细胞系中c-Met mRNA及蛋白的表达。脂质体转染c-Met-siRNA及表达质粒或AKT-siRNA,Western blotting检测转染效率;四甲基偶氮唑法(MTT法)检测细胞的活力及对阿霉素的敏感性。结果:对阿霉素耐药的MDA-MB-231/ADR细胞中cMet的mRNA及蛋白表达均显著高于对照的MDA-MB-231细胞,转染高表达c-Met的质粒可增加MDA-MB-231细胞的活力并降低其对阿霉素的敏感性,而利用siRNA抑制耐药细胞株中c-Met的表达后,可以逆转MDA-MB-231/ADR细胞对阿霉素的耐药。此外,c-Met可以磷酸化激活细胞中的AKT,并通过该信号分子增加MDA-MB-231细胞活力并诱导耐药。结论:c-Met可作为一个重要的靶点应用于三阴性乳腺癌的治疗。     

沉默miR-21对子宫内膜癌顺铂耐药细胞株Ishikawa/DDP的影响

目的:观察沉默miR-21对子宫内膜癌顺铂耐药细胞株Ishikawa/DDP的影响.方法:以Lipofectamine 2000介导miR-21抑制剂转染Ishikawa/DDP细胞株,同时设置阴性组和耐药组.采用反转录PCR检测miR-21、多药耐药基因MDR1、促凋亡基因Bax和抗凋亡基因Bcl-2的表达.采用蛋白印迹法检测多药耐药蛋白P-gp、促凋亡蛋白Bax和抗凋亡蛋白Bcl-2的表达.采用噻唑蓝比色法检测细胞对顺铂的敏感性.采用流式细胞术检测细胞凋亡情况.结果:与耐药组和阴性组比较,抑制剂组miR-21,MDR1和Bcl-2 mRNA表达显著下调(P＜0.0l),而Bax mRAN表达显著上调(P＜0.00l);抑制剂组P-gp和Bcl-2蛋白表达显著低下调(p＜0.05),而Bax蛋白表达显著上调(P＜0.001).与耐药组和阴性组比较,顺铂对抑制剂组的IC50值显著(P＜0.001);顺铂对抑制剂组细胞的诱导凋亡率显著增加(P＜0.00l).结论:沉默miR-21可显著提高Ishikawa/DDP细胞株对顺铂的敏感性,并促进细胞凋亡,其具体机制可能与下调MDR1,P-gp和Bcl-2表达,以及上调Bax表达有关.     

应用蛋白质芯片检测白血病细胞株耐药相关蛋白的表达

目的利用低密度蛋白质芯片检测白血病细胞株耐药相关蛋白的表达。方法选择与白血病耐药密切相关的11种蛋白为检测指标,制备低密度蛋白质芯片,对人白血病细胞株HL-60、K562、Jurkat及耐药细胞株HL-60/VCR、K562/ADM、人Burkitt淋巴瘤Raji细胞株细胞裂解物进行检测。结果髓系白血病耐药细胞株P-糖蛋白(P-gp)、肺耐药蛋白/主要穹窿蛋白(LRP/MVP)、谷胱甘肽-硫-转移酶-π(GST-π)、血管内皮细胞生长因子(VEGF)、黏附分子淋巴细胞功能相关抗原-1(LFA-1)表达高于非耐药细胞株,而淋巴系白血病细胞株P-糖蛋白及趋化因子受体CXCR4均有高表达。结论检测白血病耐药相关蛋白的蛋白质芯片可发现不同的白血病细胞株的耐药相关蛋白表达的差异,联合检测多种耐药相关蛋白有助于更好的研究白血病的耐药机制。     

FK228和雷帕霉素协同促进人乳腺癌细胞凋亡和细胞周期阻滞

目的:探讨组蛋白去乙酰化酶抑制剂(histone deacetylase inhibitor,HDACi)FK228和哺乳动物雷帕霉素靶蛋白(mammalian target of rapamycin,m TOR)特异性抑制剂雷帕霉素(rapamycin,Rapa)联合应用对体外人乳腺癌细胞株生长和凋亡的影响及其可能的分子机制。方法:以乳腺癌细胞系MDA-MB-435和MCF-7为研究对象,经不同浓度的FK228和雷帕霉素处理后,磺酰罗丹明B(SRB)比色法检测肿瘤细胞的生长抑制率,计算两药的联合指数;Western blotting检测乳腺癌细胞中凋亡相关蛋白、周期调控蛋白以及核酸相关蛋白的表达;流式细胞术检测细胞周期。结果:(1)FK228或雷帕霉素单独使用时均抑制肿瘤细胞生长,抑制率与时间、剂量呈正相关;当总抑制率为50%~70%时联合指数(CI)值小于1,提示两药联合应用具有协同效应;(2)联合用药后,凋亡蛋白表达较单药使用组明显升高(P0.05);同时,p-Akt蛋白表达下降,活化的caspase-3表达上调;(3)联合用药后,周期调控蛋白表达较单药使用组明显下降(P0.05),细胞周期阻滞在G2/M期;联合用药后出现更为显著的H2AX的磷酸化和H3的乙酰化(P0.05)。结论:FK228和雷帕霉素联合给药能协同促进人乳腺癌细胞凋亡和细胞周期阻滞,具有良好的抗肿瘤前景。     

MG132对乳腺癌细胞株MICA蛋白稳定性及NK杀伤活性作用

目的探讨蛋白酶体抑制剂MG132对乳腺癌细胞株MHC-I类相关分子A(MHC class I-related molecules A,MICA)蛋白稳定性及NK杀伤活性作用。方法乳腺癌细胞株MICA全基因检测。构建乳腺癌细胞株MICA等位基因真核表达载体,转染293T细胞。流式细胞术及Western blot检测乳腺癌细胞株MICA表达。MTT检测MG132对乳腺癌细胞生长抑制。LDH检测NK细胞杀伤活性。结果 MDA-MB-231基因序列为MICA*019/A5,MDA-MB-435S基因序列为MICA*010/A5,仅在蛋白N端(膜外区)第29位氨基酸有差异:MICA*019/A5在该位点为Arg(精氨酸),而MICA*010/A5在该位点为Pro(脯氨酸),Arg或Pro位点在蛋白结构的一个beta折叠上,而且是处于偏中间的位置。MG132对转染的293T细胞增殖均有明显抑制作用。MG132处理转染的293T细胞后,MDA-MB-435S MICA基因来源的293T细胞MICA表达降低,并随作用时间影响更明显,对NK杀伤敏感下降。MDA-MB-231 MICA基因来源的293T细胞MICA表达无明显改变,对NK杀伤活性敏感性不受影响。结论 NK杀伤敏感性与乳腺癌细胞MICA表达密切相关,MG132影响MDA-MB-435S MICA稳定性,所以影响NK杀伤敏感性,MDA-MB-231不受影响。     

铜绿假单胞菌噬菌体PaP3全基因组在感染宿主菌PA3过程中的分时期表达研究

目的明确铜绿假单胞菌噬菌体PaP3在感染宿主菌PA3后其全基因组的分时期表达模式。方法利用基因芯片检测噬菌体PaP3在感染宿主菌PA3后不同时间(5 min,10 min,20 min,30 min,80 min)其全基因组(含71个预测的ORF)在转录水平的表达谱变化,并进行非监督层次聚类(hierarchical clustering)分析。利用蛋白质合成抑制剂氯霉素(Cm)和DNA复制抑制剂磷酸乙酸(PAA)实验确定PaP3全基因组的分时期表达情况。结果根据时间表达模式的不同,PaP3全基因组可分为3大类:15个早期基因(ORF 71-57)、35个中期基因(ORF 56-22)及21个晚期基因(ORF 21-1)。在PaP3基因组结构中,这3类基因各自串联分布且可能受不同的操纵子调控。结论 PaP3感染过程中其早期、中期及晚期基因随时间有序表达,为深入了解噬菌体基因表达模式及生命复制周期奠定基础,并为了解噬菌体与宿主及机体免疫系统的的相互作用提供了基础。     

Catalog of 300 SNPs in 23 genes encoding G-protein coupled receptors

We previously published a series of detailed maps of single nucleotide polymorphisms (SNPs) in the genomic regions of 209 gene loci encoding drug metabolizing enzymes, transporters, receptors, and other potential drug targets. In addition to the maps reported earlier, we provide here high-resolution SNP maps of 23 genes encoding G-protein coupled receptors in the Japanese population. A total of 300 SNPs were identified through screening of these loci; 83 in four adenosine receptor family genes, 45 in three adrenergic receptor family genes, 22 in three EDG receptor family genes, 29 in three melanocortin receptor family genes, 22 in two somatostatin receptor family genes, 21 in five anonymous G protein-coupled receptor family genes, and 78 in the others (AVPR1B, OXTR, and TNFRSF1A). We also discovered a total of 33 genetic variations of other types. Of the 300 SNPs, 132 (44%) appeared to be novel on the basis of comparisons with the dbSNP database of the National Center for Biotechnology Information (US) or with previous publications. The maps constructed in this study will serve as an additional resource for studies of complex genetic diseases and drug-response phenotypes to be mapped by linkage-disequilibrium association analyses.     

Methylation status of immunoglobulin x e segments correlates with their recombination potential

We have previously shown that unlike endogenous ? genes, unrearranged ? transgenes undergo V?-J? recombination in T as well as B cells of transgenic mice. To determine whether the difference in recombination specificity of the transgenic and endogenous ? genes is associated with differences in DNA structure, the methylation status of the endogenous genes and three unrearranged ? transgenes was compared. The J?-C? locus of the transgenes was found to be hypomethylated in all tissues of the transgenic mice. In contrast, methylation of the endogenous ? genes was tissue and developmentally regulated. Hypomethylation of the endogenous J?-C? region occurs only in cells of the B lineage undergoing, or having completed ? gene recombination. Transfection of fibroblasts from transgenic and control mice with the recombination activating genes, Rag1 and Rag2, led to a high level of rearrangement of the hypomethylated transgenic, but not the endogenous ? genes. These results suggest that hypomethylation defines an accessible state of the ? locus and that methylation/demethylation could be involved in the control of ? gene rearrangement during lymphocyte differentiation.     

Incidence of SUC-RTM telomeric repeated genes in brewing and wild wine strains of Saccharomyces

When over-expressed, RTM yeast genes confer resistance to the toxicity of molasses. They are found in distiller's and baker's industrial yeasts in multiple copies, scattered on the telomeres and physically linked to the telomeric SUC genes. Because these genes are absent from some laboratory strains, we explored the genomes of other industrial yeasts (brewing strains) and wine wild strains. A collection of 47 wine yeast strains (S. cerevisiae and S. bayanus) and 15 brewing strains, lager, ale and possible ancestors (S. monacensis, S. paradoxus and S. carlsbergensis) were screened for the presence of RTM genes. Only three wine strains and all brewing strains proved to contain RTM sequences in different copy numbers. PCR and chromosome blotting confirm the presence of SUC sequences in tandem with RTM. Moreover, analysis of the entire S. cerevisiae genome sequence shows that three other, non-telomeric, genes related to RTM are scattered on different chromosomes. Received: 4 December 1996     

鼻咽癌组织中bcl-2、bax和p53的表达及其与瘤细胞凋亡的关系

目的：了解鼻咽癌组织中瘤细胞ｂｃｌ２、ｂａｘ和ｐ５３的表达及其与瘤细胞凋亡指数（ａｐｏｐｔｏｓｉｓｉｎｄｅｘ,ＡＩ）的关系。方法：对３８例未经治疗的鼻咽癌组织,应用免疫组化ＬＳＡＢ法检测瘤细胞ｂｃｌ２、ｂａｘ和ｐ５３的表达;末端标记细胞死亡检测法（ＴＵＮＥＬ）计算癌细胞的凋亡指数。结果：（１）３７例（９７４％）中有９０％左右的瘤细胞呈ｂｃｌ２过表达;（２）３８例（１００％）中有７０％左右的瘤细胞过表达ｂａｘ;（３）２９例（７６３％）呈ｐ５３过表达;（４）３８例活检组织的平均ＡＩ为２６０２±２６４２／ＨＰＦ;（５）ＡＩ与ｂｃｌ２、ｂａｘ和ｐ５３的表达无相关性。结论：（１）本组大多数鼻咽癌组织的绝大部分瘤细胞均呈ｂｃｌ２和ｂａｘ高表达;（２）由于ｂｃｌ２和ｂａｘ的表达已在高水平达到相对平衡,因此在大多数人体鼻咽癌中它们可能并不起到介导瘤细胞凋亡的主导作用;（３）鼻咽癌组织中过表达的ｐ５３蛋白可能已失去了调节ｂｃｌ２和ｂａｘ的表达进而影响细胞凋亡的功能。     

Effects of ultra-marathon on circulating DNA and mRNA expression of pro- and anti-apoptotic genes in mononuclear cells

We investigated the effects of an ultra-marathon on cell-free plasma DNA as well as on mRNA expression of pro-apoptotic (Bax, Bad), anti-apoptotic (Bcl-2) and cell-protective (Hsp70, Hsp27 and Hsp32) genes in mononuclear blood cells (MNCs). Blood samples were drawn from 14 athletes before and immediately after 6-h run. In addition, blood samples were also collected and analyzed 2 and 24 h after the end of the run. Levels of plasma DNA were significantly increased immediately after the marathon (P < 0.001) and were still higher 2 h later (P < 0.005), but significantly lower than those immediately after the race (P < 0.05). Cell-free plasma DNA returned to pre-race levels 24 h after the run. mRNA expressions of Hsp70, Hsp32 and Bax significantly increased in MNCs after the race, whereas Hsp27 and Bad mRNA expression levels showed no significant changes. Bcl-2 expressions decreased immediately after the race (P < 0.001), but increased in the 24 h later (P < 0.05). We conclude that apoptotic ladders of cell-free DNA following exhaustive exercise originate from apoptotic cells and that not only skeletal muscle cells but also leukocytes contribute to this phenomenon. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Protection from insulin-dependent diabetes mellitus is linked to a peptide transporter gene

HLA class II association with insulin-dependent diabetes mellitus (IDDM) is well established but is still difficult to map to a particular locus. Polymorphism of the genes coding for transporter associated with antigen processing (TAP1 and TAP2), and located in the HLA class II region, was studied in 167 IDDM patients (116 adult-onset and 51 childhood-onset patients) and 98 normal controls using oligotyping after genomic amplification. A dominant protective effect was observed for theTAP2*0201 allele [relative risk (RR)=0.3, corrected probability (pc) < 0.001]. Conversely, susceptibility to IDDM was associated with apparent homozygosity for the TAP2*0101 allele (RR=3.4, pc < 0.001). Protection was independent from but additive to the protection conferred by the DRB1*02 DQB1*0602 haplotype (RR=0.06, pc<0.05), and antagonistic to the DRB1*03 DQB1*0201 and DRB1*04 DQB 1*0302 haplotypes predisposing effect (RR=1.1, not significant), arguing in favor of an absence of linkage disequilibrium between TAP2 and HLA class II genes. This was assessed by x² analysis. TAP1 allelic distribution was not different among diabetics and controls. A significant association was observed between the presence of TAP2*0101 and that of islet cell antibodies (p < 0.05). These data suggest that the TAP2 gene, which encodes protein required for delivery of antigen peptides to class I molecules in the endoplasmic reticulum, could modulate the autoimmune response leading to β cell destruction. From a practical point of view, they make the combined screening of HLA class II and TAP2 loci a highly valuable tool in IDDM prediction.