Study of radiation induced changes of phosphorus metabolism in mice by (31)P NMR spectroscopy

Background

The aim of this study was to examine whether ³¹P NMR can efficiently detect X-ray radiation induced changes of energy metabolism in mice. Exposure to ionizing radiation causes changes in energy supply that are associated with the tissue damage because of oxidative stress and uncoupled oxidative phosphorylation. This has as a consequence decreased phosphocreatine to adenosine triphosphate ratio (Pcr/ATP) as well as increased creatine kinase (CK) and liver enzymes (transaminases AST and ALT) levels in serum.

Materials and methods

In this study, experimental mice that received 7 Gy of X-ray radiation and a control group were studied by ³¹P NMR spectroscopy and biochemically by measuring CK and liver enzyme levels in plasma. Mice (irradiated and control) were measured at regular time intervals for the next three weeks after the exposure to radiation.

Results

A significant change in the Pcr/ATP ratio, determined from corresponding peaks of ³¹P NMR spectra, was observed in the 7 Gy group 2 days or more after the irradiation, while no significant change in the Pcr/ATP ratio, was observed in the control group. This result was supported by parallel measurements of CK levels that were highly increased immediately after the irradiation which correlates with the observed decrease of the Pcr/ATP ratio and with it associated drop of muscle energy supply.

Conclusions

The ³¹P NMR measurements of the Pcr/ATP ratio can in principle serve as an instantaneous and noninvasive index for assessment of the received dose of irradiation.     

Infrared spectroscopic study of bryostatin 1-induced membrane alterations in a B-CLL cell line.

Previous studies on intact cells have shown that bryostatin 1 (Bryo 1) induces significant alterations in the membranes of WSU-CLL cells (a drug-resistant B-CLL cell line), changes which may play an important role in the mechanism of reduced drug resistance of B-CLL cells to 2-chlorodeoxyadenosine (2-CdA). However, it is not clear whether the plasma membranes or the mitochondria, or both are involved; nor is it known which of these two targets is more important for regaining the cells former drug sensitivity. For the present study, we treated WSU-CLL cells with Bryo 1, isolated plasma membranes and mitochondria, and then subjected the purified fractions to infrared (IR) spectroscopic and chromatographic analyses. IR spectroscopy revealed a decreased glycosylation of both plasma membranes and mitochondria in Bryo 1-treated cells compared to untreated cells. The amount of lipid relative to protein was increased in both types of membranes, but considerably more enhanced in the plasma membrane fraction of the Bryo 1-treated cells than in mitochondria. Quantitative lipid analysis by thin layer chromatography also revealed that Bryo 1 treatment significantly increased the phospholipid content in plasma membranes, whereas the lipids in the mitochondria remained essentially unchanged. Changes in lipid composition were quite dramatic for plasma membranes where phosphatidylcholines were decreased by 50%, phosphatidylethanolamines doubled and sphingomyelins increased five-fold compared to the lipid composition in plasma membranes of untreated cells. In addition, the IR spectroscopic analysis provided evidence for an increased plasma membrane fluidity in Bryo 1-treated cells, whereas the fluidity of the mitochondria remained essentially unchanged; marker bands indicating mitochondrial DNA decreased upon Bryo 1 treatment. These results suggest that Bryo 1 increases the sensitivity of WSU-CLL cells to chemotherapeutic agents such as 2-CdA by action on two cell targets: (1) introduction of significant changes in plasma membrane permeability or fluidity through modifications in lipid content and composition as well as by reducing the surface glycosylation; (2) introduction of changes in lipid and DNA content of the mitochondria. Small alterations in the lipid composition of the mitochondria may provide the conditions for an altered proton gradient and transmembrane potential leading to apoptosis and decreased cell survival.     

31P nuclear magnetic resonance study of a human colon adenocarcinoma cultured cell line

31P nuclear magnetic resonance (NMR) spectroscopy has been used to monitor the energy metabolism in a human colon adenocarcinoma cell line (HT 29). NMR spectra were recorded at 80.9 MHz on approximately 2.5 X 10(8) cells continuously perfused with culture medium within a 20-mm NMR sample tube. Typical NMR spectra display a series of well-resolved resonances assigned to nucleoside triphosphates (mainly adenosine 5'-triphosphate), uridine diphosphohexose derivatives (uridine 5'-diphosphate-N-acetylglucosamine, uridine 5'-diphosphate-N-acetylgalactosamine, uridine 5'-diphosphate-glucose), intra- and extracellular inorganic phosphate, and phosphomonoesters (mainly phosphorylcholine and glucose 6-phosphate). Measurement of phosphorylated metabolite concentrations from the intensity of NMR signals is in good agreement with the results provided by conventional biochemical assays. 31P NMR allows to follow noninvasively the effect of anoxia on HT 29 cells. The results indicate that the cells are able to maintain about 60% of their initial nucleoside triphosphate level after 2 h of anaerobic perfusion. Cells accumulate inorganic phosphate during anoxia and the intracellular-extracellular pH gradient increases from 0.5 in well-oxygenated cells to more than 1 pH unit under anoxic conditions. The value of intracellular pH of well-oxygenated HT 29 cells is 7.1. The effect of glucose starvation upon energy metabolism has also been examined in real time by NMR: a rapid decline of adenosine 5'-triphosphate down to 10% of the initial value is observed over a period of 2 h. In contrast, the level in uridine diphosphohexoses reaches a new steady state value representing 60% of the initial one. Refeeding the cells with 25 mM glucose leads to a dramatic drop of internal pH reflecting the activation of the glycolytic pathway.     

阿霉素热化疗对肝癌细胞增殖和凋亡的影响

目的:探讨阿霉素(ADM)加热化疗对人肝癌细胞HHCC及HepG2的增殖抑制和凋亡诱导作用。方法:以体外培养的人肝癌细胞HHCC和HepG2为研究对象,采用水浴加温法,观察单纯热疗,ADM化疗和热化疗对细胞增殖和凋亡的影响。MTT法确定阿霉素的工作浓度并检测细胞增殖的抑制作用,流式细胞术检测细胞凋亡。结果:热化疗组细胞的抑制率显著高于单纯热疗、单纯化疗组[HHCC细胞:(65.77±2.54)%vs(23.18±0.81)%、(38.35±2.23)%,P<0.05。HepG2细胞:(74.25±1.53)%vs(1 7.1 2±2.8 6)%、(30.35±5.90)%,P<0.05]。热化疗组细胞凋亡率显著高于单纯热疗组、单纯化疗组[HHCC细胞:(76.1±2.33)%vs(23.83±1.76)%、(45.57±2.81)%,P<0.05。HepG2细胞:(76.9±2.79)%vs(19.7±7.63)%、(37.43±1.88)%,P<0.05]。结论:加热能增强ADM对HHCC及HepG2的增殖抑制和诱导凋亡作用。     

Metabolic signatures associated with a NAD synthesis inhibitor-induced tumor apoptosis identified by 1H-decoupled-31P magnetic resonance spectroscopy.

PURPOSE: Attempts to selectively initiate tumor cell death through inducible apoptotic pathways are increasingly being exploited as a potential anticancer strategy. Inhibition of NAD+ synthesis by a novel agent FK866 has been recently reported to induce apoptosis in human leukemia, hepatocarcinoma cells in vitro, and various types of tumor xenografts in vivo. In the present study, we used 1H-decoupled phosphorus (31P) magnetic resonance spectroscopy (MRS) to examine the metabolic changes associated with FK866 induced tumor cell death in a mouse mammary carcinoma. EXPERIMENTAL DESIGN: Induction of apoptosis in FK866-treated tumors was confirmed by histology and cytofluorometric analysis. FK866-induced changes in mammary carcinoma tumor metabolism in vivo were investigated using 1H-decoupled 31P MRS. To discern further the changes in metabolic profiles of tumors observed in vivo, high-resolution in vitro 1H-decoupled 31P MRS studies were carried out with perchloric acid extracts of mammary carcinoma tumors excised after similar treatments. In addition, the effects of FK866 on mammary carcinoma tumor growth and radiation sensitivity were studied. RESULTS: Treatment with FK866 induced a tumor growth delay and enhanced radiation sensitivity in mammary carcinoma tumors that was associated with significant increases in the 31P MR signal in the phosphomonoester region and a decrease in NAD+ levels, pH, and bioenergetic status. The 31P MRS of perchloric acid extracts of treated tumors identified the large unresolved signal in the phosphomonoester region as the resultant of resonances originating from intermediates of tumor glycolysis and guanylate synthesis in addition to alterations in pyridine nucleotide pools and phospholipid metabolism. CONCLUSION: The present results suggest that FK866 interferes with multiple biochemical pathways that contribute to the increased cell death (apoptosis) and subsequent radiation sensitivity observed in the mammary carcinoma that could be serially monitored by 31P MRS.     

Methodology for applied 4 MHz RF hyperthermia concomitant with 31P NMR spectroscopic monitoring of murine tumours.

It has been generally found that solid tumours in vivo are more susceptible to destruction by heat than normal tissues. Hyperthermia has, thus, been employed in the treatment of cancer either applied alone or in combination with other modalities such as chemotherapy and radiotherapy. However, the critical mechanism(s) by which heat sensitizes and kills cells in the solid tumour remains poorly defined. Magnetic resonance spectroscopic monitoring of tumour metabolism during application of hyperthermia may provide important insight into the response to hyperthermic challenge. The implementation of dual antenna-coil methodology that provides for NMR spectroscopic monitoring (31P at 121 MHz) concomitant with applied 4 MHz RF hyperthermia in murine tumours is described herein, in some detail. This technology, which does not require advanced (and expensive) magnetic resonance imaging systems, should be readily adaptable by other laboratories with an interest in murine tumour models.     

Establishment of an erythroid cell line (JK-1) that spontaneously differentiates to red cells

The authors established a new hemopoietic cell line (JK-1) from a patient with chronic myelogenous leukemia in erythroid crisis. This JK-1 line predominantly consists of immature cells, but a small number of mature erythroblasts and red cells can be consistently seen without any specific differentiation inducer. The JK-1 cells grow in suspension culture supplemented with human plasma and carry double Philadelphia chromosomes. Hemoglobin staining with benzidine was positive for about 20% of cells and the type of the hemoglobin was for the most part HbF. Surface-marker analysis revealed JK-1 cells positive for glycophorin A, EP-1, and HAE9. The proportion of mature cells was elevated by the addition of delta-aminolevulinic acid. Erythropoietin (EPO) enhanced the growth of JK-1 cells either in the suspension or in methylcellulose semisolid culture. The total number of EPO receptors was 940 per cell, of which 220 sites had an affinity higher than the other 720 sites. This is the first report of an established human erythroid cell line which spontaneously undergoes terminal differentiation.     

In vitro apoptosis in the human hepatoma cell line induced by transforming growth factor beta 1.

The effect of transforming growth factor beta 1 (TGF-beta 1) on human hepatoma cells (Hep 3B) was studied. Cell death was observed when the serum starved Hep 3B cells were exposed to a very low concentration of TGF-beta 1. The half-maximal cytocidal concentration of TGF-beta 1 was around 20 pM. Cell death began approximately 24 h following treatment, with more than 80% of the cells dying after 48 h. In contrast, the control cells, which were cultured in serum-free condition, still gradually proliferated. Furthermore, the cytocidal effect of TGF-beta 1 on Hep 3B cells was not altered by either cycloheximide or actinomycin D. It was discovered, using diphenylamine assay, that TGF-beta 1 induced DNA fragmentation in Hep 3B cells. Using gel electrophoresis, the fragmented DNA could be displayed, and showed a characteristic stepladder pattern. Thus, it appeared that TGF-beta 1 induced a particular pathway in Hep 3B cells in which de novo protein synthesis was not actively involved, but endogenous nuclease was activated which cleaves cellular DNA and induces cell death.     

姜黄素损伤线粒体诱导食管癌Ec-109细胞凋亡的研究

目的:探讨姜黄素损伤线粒体诱导食管癌Ec-109细胞凋亡的作用机制。方法:80μmol/mL姜黄素作用于食管癌Ec-109细胞不同时间后,流式细胞仪检测细胞亚二倍体凋亡峰变化及线粒体膜电位变化;蛋白质印迹法检测细胞色素C释放及Caspase-9表达。结果:姜黄素呈时间依赖性诱导食管癌Ec-109细胞凋亡,12、24和48 h细胞亚二倍体凋亡峰分别为(15.89±2.12)%、(26.80±1.87)%和(36.97±1.80)%,对照组为(3.23±0.24)%,总体比较差异有统计学意义,F=6.75,P<0.01,各组间比较差异均有统计学意义,P<0.01。姜黄素作用3、6和12 h后线粒体膜电位分别为84.78%、67.03%和63.16%,对照组为97.17%,差异有统计学意义,F=5.12,P<0.05,各组间比较,6 h组与12 h组差异无统计学意义,P=0.062,余各组间有差别;6 h出现细胞色素C表达,12 h表达最高;12 h检测到Caspase-9表达,24 h表达最高。结论:姜黄素呈时间依赖性诱导食管癌细胞凋亡是通过损伤细胞线粒体、使之释放出细胞色素C以及激活Caspase-9实现的。     

吲哚美辛诱导食管癌EC109细胞凋亡的Smac依赖性机制

目的:研究Smac表达下调对吲哚美辛诱导的食管癌EC109细胞凋亡的影响,并探索其内在分子机制。方法:使用Smac-siRNA脂质体法转染食管癌EC109细胞,将细胞分为空白对照组, siRNA-control阴性对照组和siRNA-Smac组。使用不同浓度的吲哚美辛处理各组细胞,MTT检测细胞活力变化,流式细胞术检测其对细胞凋亡的影响,Western blot法检测Caspase-9、3以及XIAP、survivin表达情况。结果:采用不同浓度吲哚美辛处理后,细胞活力明显受到抑制;Smac siRNA可明显降低Smac在RNA水平和蛋白水平的表达;吲哚美辛可引起各组凋亡率明显增加,单纯导入siRNA-Smac片段并不能引起细胞凋亡变化,siRNA-Smac联合药物能明显降低EC109细胞凋亡率（P＜0.05）。在蛋白水平,siRNA-Smac组的survivin表达无明显变化,XIAP表达明显增强;Caspase-9及Caspase-3的活性片段明显表达减弱（P＜0.05）。结论:NSAIDs药物吲哚美辛可诱导食管癌EC109细胞凋亡,这种作用一定程度上依赖于Smac的正常表达;Smac表达降低后其对XIAP的抑制减弱,Caspase-9和Caspase-3的活化受到抑制,而survivin在其中并不起决定性作用。     

三氧化二砷诱导人肝癌细胞株SMMC-7721凋亡的实验研究

 MTT法、AO/EB荧光染色法和流式细胞仪分析法观察As₂O₃对人肝癌细胞林SMMC-7721的作用.结果发现:As₂O₃可显著抑制SMMC-7721细胞的生长;经药物作用后,AO/EB染色时,肝癌细胞在显微镜下呈现典型的凋亡形态学改变;在流式细胞仪上可见亚G_l峰;凋亡呈剂量,时间依赖性特点;As₂O₃使细胞周期阻止于G₂/M期.以上表明:As₂O₃可诱导人肝癌细胞株凋亡,可望为临床应用砷剂治疗肝癌提供实验依据.     

三氧化二砷诱导卵巢癌OVCAR-3细胞周期阻滞及凋亡

目的探讨As2O3对卵巢癌细胞增殖的抑制作用及对细胞周期和凋亡的影响.方法采用MTT法及集落形成实验测定细胞的增殖活力,通过细胞形态学观察细胞分裂及凋亡,应用流式细胞仪进行细胞周期解析、凋亡及bcl-2蛋白表达的检测.结果As2O3呈剂量依赖性抑制OVCAR-3细胞增殖,抑制50%细胞生长的药物浓度(IC50)为2μmol/L.0.5～5μmol/L的As2O3作用7天,集落抑制率均在40%以上(P＜0.01).2μmol/L与5μmol/L的As2O3作用12 h后,细胞周期出现了G2/M期阻滞及亚二倍体凋亡峰,随着作用时间的延长,凋亡细胞随G2/M期细胞减少而逐渐增多.细胞形态学观察可见分裂期细胞及凋亡细胞明显增加.0.5～5μmol/L的As2O3均能下调bcl-2蛋白的表达.结论As2O3能够抑制卵巢癌OVCAR-3细胞的增殖,诱导M期阻滞及细胞凋亡.     

Cell cycle inhibition and apoptosis induced by curcumin in Ewing sarcoma cell line SK-NEP-1

Curcumin is a naturally occurring polyphenolic compound found in the turmeric, which is used as food additive in Indian cooking and as a therapeutic agent in traditional Indian medicine. Curcumin is currently under investigation as a chemotherapeutic and chemopreventive agent in adult cancer models at both pre-clinical and clinical levels. In this preliminary study, we show that curcumin is effective in causing cell cycle arrest, inducing apoptosis, and suppressing colony formation in the Ewing sarcoma cell line SK-NEP-1. Curcumin causes upregulation of cleaved caspase 3 and downregulation of phospho-Akt, producing apoptosis in Ewing sarcoma cells at an inhibitory concentration 50% (IC50) of approximately 4 μM. Our findings indicate a need for further evaluation of curcumin in chemotherapy and chemoprevention of Ewing sarcoma.     

Cuphiin D1, the macrocyclic hydrolyzable tannin induced apoptosis in HL-60 cell line

Cuphiin D1 (CD1), a new macrocyclic hydrolyzable tannin isolated from Cuphea hyssopifolia, has been shown to exert antitumor activity both in vitro and in vivo. In this study, we explored the mechanism of the CD1-induced antitumor effect on human promyelocytic leukemia (HL-60) cells. The results showed that CD1 induced cytotoxicity in HL-60 cells and the IC50 was 16 microM after 36 h treatment. HL-60 cells treated with CD1 for 36 h decreased the uptake of [3H]-labeled thymidine, uridine and leucine in a dose dependent manner. Electron micrographs demonstrated that HL-60 cells treated with 16 microM CD1 for 36 h exhibited chromatin condensation, indicating the apoptosis occurrence. Flow cytometric analysis demonstrated the presence of apoptotic cells with low DNA content, a decrease of cell population at G2/M phase, and a concomitant increase of cell population at G1 phase. CD1 also caused DNA fragmentation and inhibited Bcl-2 expression in the HL-60 cells. These results suggest that the inhibition of Bcl-2 expression in HL-60 cell might account for the mechanism of CD1-induced apoptosis.     

An increase in the expression and total activity of endogenous p60(c-Src) in several factor-independent mutants of a human GM-CSF-dependent leukemia cell line (TF-1)

Growth factor independence of hematopoietic cells can be induced by ectopic expression of a variety of oncogenes encoding receptor or cytoplasmic tyrosine kinases. To examine whether the activation of tyrosine kinases occurs in factor-independent mutants in vivo, the tyrosine-phosphorylated proteins from 14 factor-independent mutants of a GM-CSF-dependent cell line (TF-1) were analysed. These mutants did not secrete any growth-stimulating activity for TF-1 cells, suggesting that activation of intracellular signaling rather than an autocrine stimulation by secreted growth factors is responsible for their factor-independent growth. In 11 out of 14 GM-CSF-independent mutants analysed, a constitutively tyrosine-phosphorylated protein of 60 kDa was detected, which was subsequently identified as p60(c-Src). The kinase activity of p60(c-Src) was increased up to 12-fold in these mutants, which was at least in part due to overexpression of the c-src gene on the RNA and protein level. The Src substrate Sam68 showed an increased phosphorylation in mutants with high Src activity, suggesting that p60(c-Src) triggers downstream signaling in these cells. Treatment of the factor-independent mutants with the Src kinase inhibitor PP2 resulted in a reduced proliferation, demonstrating that Src kinases are essential for these cells for maximal proliferation. Further analysis of factor-independent mutants with low or undetectable Src activity revealed a constitutive phosphorylation of the common beta chain of the GM-CSF receptor and STAT5. Our data indicate an increase in the expression and total activity of endogenous p60(c-Src) in several GM-CSF-independent TF-1 mutants, further underlining the role of Src in the process of autonomous growth of hematopoietic cells.     

程序性细胞死亡蛋白5在米非司酮诱导前列腺癌细胞凋亡中的协同作用

目的:观察程序性细胞死亡蛋白5(programmed cell death 5,PDCD5)在米非司酮(mifepristone,MIF)诱导的前列腺癌细胞凋亡中的作用,并探讨其机制.方法:MTT法检测不同浓度(5、10、20、50、100 μmol/L)的MIF作用前列腺癌PC-3M细胞24～96 h后的吸光度(D)值,找到最佳作用时间及浓度.将真核表达载体PCI-neo-PDCD5用脂质体介导的方法转染入PC-3M细胞后,采用细胞免疫荧光法检测PDCD5蛋白的表达水平.在转染PDCD5基因的细胞中加入最佳作用浓度的MIF,继续培养24、48 h后,采用TUNEL和吖啶橙(acrine orange,AO)/溴化乙锭(ethidium bromide,EB)法检测细胞凋亡情况,Western印迹法检测凋亡相关蛋白caspase-3的表达变化.结果:MTT检测结果显示,与对照组相比,5、10 μmol/L MIF组的D值没有显著变化(P>0.05),20、50和100 μmol/L MIF组的D值显著降低(P<0.05),说明MIF对前列腺癌PC-3M细胞的抑制作用呈时间和剂量依赖性.PDCD5基因真核表达载体成功转染入PC-3M细胞,并得到高表达.TUNEL和AO/EB检测结果显示,与对照组及单独应用MIF组相比,转染PDCD5基因并加入MIF后的细胞凋亡率显著增加(P<0.01);Western印迹结果显示,caspase-3蛋白在PDCD5与MIF联合作用时的表达明显增加(P<0.01).结论:外源性PDCD5在MIF诱导的前列腺癌细胞凋亡中有明显的正协同作用,推测其有望成为前列腺癌临床治疗的一个辅助药物.     

Suppression of myeloid cell leukemia-1 (Mcl-1) enhances chemotherapy-associated apoptosis in gastric cancer cells

Background

Myeloid cell leukemia-1 (Mcl-1) is an anti-apoptotic protein that regulates apoptosis sensitivity in a variety of cell types. Here we evaluate the roles of Mcl-1 in chemotherapy-associated apoptosis in gastric cancer cells. In addition, our study examined whether Mcl-1 contributed to apoptosis resistance in so-called cancer stem cell (CSC)-like populations in gastric cancer.

Methods

Seven gastric cancer cell lines were used. The expression of Mcl-1 was assessed by either real-time polymerase chain reaction or Western blot analysis. Apoptosis was quantitated by morphological observation and caspase activity measurement. Adenovirus-mediated RNA interference (RNAi) technology was used to knockdown the expression of Mcl-1. The release of cytochrome c was evaluated by subcellular fractionation and immunoblot analysis. To identify and isolate the CSC-like populations, we used the CSC-associated cell surface marker CD44 and flow cytometry.

Results

Six out of the 7 gastric cancer cell lines overexpressed Mcl-1 protein. These Mcl-1-expressing cell lines were relatively resistant to chemotherapeutic agents such as 5-fluorouracil (5-FU) and cisplatin (CDDP). Depletion of Mcl-1 protein by RNAi technology effectively sensitized the cells to anticancer drug-induced mitochondrial cytochrome c release, caspase activation, and apoptosis. In addition, vast amounts of Mcl-1 mRNA were expressed in CD44-positive CSC-like cells. Mcl-1 suppression enhanced the apoptosis in CD44-positive cells to a level equivalent to that in CD44-negative cells, suggesting that Mcl-1 mediates chemotherapy resistance in CSC-like populations.

Conclusion

These results suggest that Mcl-1 mediates the resistance to apoptosis in gastric cancer cells by blocking the mitochondrial pathway of cell death. Mcl-1 depletion appears to be an attractive strategy to overcome chemotherapy resistance in gastric cancer cells.     

免疫效应细胞促进阿霉素诱导乳腺癌耐药细胞凋亡

目的 探讨免疫效应细胞促进阿霉素（ADR）诱导乳腺癌耐药细胞MCF7／ADR凋亡的作用机制。方法 采用干扰素-γ（IFN-γ）、CD3单抗、白介素（IL）-1和IL-2诱导并扩增免疫效应细胞。利用末端脱氧核苷酸转移酶介导的dUTP缺口末端标记（TUNEL）技术和P-糖蛋白（P-gP）免疫组织化学染色,观察P-gP表达与凋亡的关系。用流式细胞术检测乳腺癌相关抗原P185蛋白的表达,以及Annexin V-FITC／PI阳性率。荧光显微镜下观察ADR在靶细胞内的分布和Annexin V的表达。结果 免疫效应细胞使MCF7／ADR细胞P185和P-gP表达明显下降,CIK细胞作用后,MCF7／ADR细胞P185标记荧光几何均数下降了91．9％。免疫效应细胞增加了ADR在MCF7／ADR细胞内的积累及其在细胞核的分布。联合应用免疫效应细胞和ADR后,MCF7／ADR细胞凋亡率达78．9％,比单纯加入ADR组增高了10倍,较单纯加入免疫效应细胞组增高了13倍。结论 免疫效应细胞可同时下调P185蛋白和P-gp蛋白的表达,协同ADR可提高MCF7／ADR细胞的凋亡率。     

TIMP-1降低无血清培养所致的乳腺癌细胞MCF-7凋亡的研究

目的:基质金属蛋白酶组织抑制剂-1(tissue inhibitor of metalloproteinase-1,TIMP-1)是与乳腺癌预后不良显著相关的分子。本研究旨在探讨TIMP-1的作用机制是否包括其降低无血清所导致的细胞凋亡。方法:对TIMP-1表达质粒进行酶切及序列测定;用脂质体转染的方法将含TIMP-1的质粒及对照质粒分别转染到MCF-7细胞中,Western blot检测TIMP-1蛋白的表达;在无血清培养条件下,流式细胞仪检测对照质粒转染克隆与TIMP-1稳定表达克隆凋亡的变化。结果:与转染对照质粒的克隆相比,TIMP-1转染克隆中TIMP-1蛋白的表达显著上调。无血清培养条件下,对照克隆细胞相对凋亡率为(7.18±1.12)%,TIMP-1表达克隆T10和T13相对细胞凋亡率分别为(2.63±0.39)%和(1.07±0.9)%(P<0.05)。结论:TIMP-1过表达降低无血清所导致的细胞凋亡。