补骨脂素对HL60耐药细胞内化疗药物浓度影响研究

目的研究补骨脂素对HT耐药白血病细胞HL60／HT的逆转多药耐药（MDR）作用。方法采用MTT法测定补骨脂素对细胞增殖抑制作用,高效液相色谱法检测细胞内HT的浓度。结果补骨脂素在1～20μmol／L浓度下能不同程度降低HT对HL60／HT细胞的IC50,并不同程度提高细胞内HT浓度。结论补骨脂素能逆转HL60／HT细胞的MDR作用,可能成为一种MDR调节剂。     

三氧化二砷逆转乳腺癌细胞株MCF-7/ADM多药耐药的研究

目的探讨三氧化二砷（As2O3）体外逆转人乳腺癌细胞多药耐药性的作用及机制。方法采用MTT法检测As2O3的细胞毒作用和处理前后耐药细胞对化疗药物的敏感性,用流式细胞仪检测细胞内阿霉素浓度,通过RT-RCR检测MDR1基因的表达。结果 As2O3在0.25mg/L以下剂量时对MCF-7和MCF-7/ADM耐药细胞株的抑制率均小于15%,半数抑制率（IC50）分别为1.01m/L和1.28mg/L,无细胞毒剂量0.2mg/L的As2O3能部分逆转MCF-7/ADM细胞对阿霉素的耐药性。同时无细胞毒剂量0.2mg/L的As2O3能使MCF-7/ADM细胞内阿霉素浓度明显增加,MDR1表达下降。结论 As2O3具有体外部分逆转人乳腺癌细胞多药耐药性的作用,可能与增加细胞内药物积累、下调MDR1表达有关。     

青蒿琥酯逆转Eca109/ABCG2细胞对阿霉素耐药的作用及机制

目的研究青蒿琥酯(Art)逆转食管癌耐药细胞Eca109/ABCG2对阿霉素(ADM)耐药的作用及其机制。方法采用不同浓度的青蒿琥酯(Art,0、0.01、0.1、1μmol/L),阿霉素(ADM,0、0.02、0.2、2、20mg/L),Art(0.01、0.1、1μmol/L)+ADM(0.02、0.2、2、20mg/L)处理Eca109/ABCG2细胞48h,然后以MTT法检测细胞生长抑制率。采用ADM(0、0.02、0.2、2mg/L),Art(0、0.01、0.1、1μmol/L)和ADM(0.2mg/L)+Art(0.01、0.1、1μmol/L)处理细胞,48h后以流式细胞术(FCM)检测细胞凋亡率及细胞内ADM含量,72h后检测细胞内ABCG2蛋白的表达。结果与单独应用Art或ADM相比,Art+ADM处理后,Eca109/ABCG2细胞的生长抑制率、凋亡率和细胞内ADM含量均显著增加(P<0.05),而细胞内ABCG2蛋白表达显著降低(P<0.05)。结论 Art可通过下调Eca109/ABCG2细胞ABCG2蛋白表达,增加细胞内ADM的药物浓度,从而增强疗效、逆转耐药。     

PPMP调控KBv_(200)细胞株mdr1基因表达逆转其多药耐药

为研究糖脂合成酶抑制剂苯基棕榈酰胺吗啡丙醇 (DL threo 1 phenyl 2 palmitoylamino 3 morpholi no 1 propanol·HCl,PPMP)对人恶性肿瘤多药耐药细胞株KBv2 0 0 多药耐药mdr1基因的mRNA表达的调控 ,以及PPMP对细胞株KBv2 0 0 的多药耐药性的逆转作用 ,作者应用体外细胞培养技术对细胞株KBv2 0 0 进行PPMP处理 ,用RT PCR技术分析PPMP处理前后细胞mdr1的mRNA表达 ,以流式细胞仪检测PPMP处理前后KBv2 0 0 及其敏感株KB细胞内罗丹明 12 3的药物浓度变化。结果显示 5 μmol/L、15 μmol/LPPMP可部分抑制KBv2 0 0 细胞mdr1mRNA表达 ,2 5 μmol/LPPMP可完全抑制KBv2 0 0 细胞mdr1mRNA表达 ;PPMP可增加KBv2 0 0 细胞内罗丹明荧光强度 ,随着PPMP浓度的增加 ,耐药细胞内的罗丹明荧光强度逐渐增大。提示PPMP对细胞株KBv2 0 0 的多药耐药基因mdr1有抑制作用 ,并可以逆转KBv2 0 0 的多药耐药性 ,逆转作用与PPMP浓度呈正相关     

原儿茶醛对叔丁基过氧化氢损伤HepG2细胞的保护作用

目的:考察原儿茶醛(PCA)对氧化损伤HepG2细胞的保护作用及其作用机制.方法:200 μmol/L叔丁基过氧化氢(t-BHP)损伤HepG2细胞,检测不同浓度原儿茶醛对细胞活力、超氧化物歧化酶活性、细胞内还原型谷胱甘肽及活性氧族的影响.结果:200 μmol/L叔丁基过氧化氢可以显著性地损伤HepG2细胞,原儿茶醛给药能够显著提高损伤细胞的活力、提升超氧化物歧化酶的活性、降低细胞内活性氧族的含量、增加细胞内还原型谷胱甘肽的含量.结论:原儿茶醛对HepG2细胞有保护作用,其作用机制可能是通过提高抗氧化酶活性、加快活性氧的清除实现细胞保护作用.     

重组人p53腺病毒在乳腺癌裸鼠体内耐药逆转作用及其对P-糖蛋白表达的影响

目的 研究重组人p53腺病毒（rAd-p53）对人乳腺癌MCF-7/ADR裸鼠移植瘤的耐药逆转作用及其对耐药相关P-糖蛋白（P-glycoprotein,P-gp）表达的影响.方法 建立人乳腺癌MCF-7/ADR裸鼠耐药模型,随机分为对照组、rAd-p53组、阿霉素组、联合组,分别给予不同治疗.观察裸鼠肿瘤体积的变化,western blot检测P-gp蛋白表达情况.结果 成瘤后rAd-p53组、阿霉素组、联合组抑瘤率分别为42.05％、49.21％、69.97％,各治疗组体积与对照组相比差异有统计学意义（P＜0.05）,且联合组显著优于rAd-p53组和阿霉素组（P＜0.05）.对照组、rAd-p53组、阿霉素组、联合组P-gp表达水平分别为（0.5964±0.0806）、（0.5506±0.0127）、（0.5641±0.0055）、（0.4652±0.0982）,联合组P-gp表达水平低于其他各组.结论 Ad-p53对人乳腺癌阿霉素耐药细胞株MCF4/ADR建立的裸鼠移植瘤具有多药耐药的逆转作用,并可下调P-gp的表达.     

过氧化氢对乳鼠心肌细胞内游离钙浓度的影响及卡维地洛的拮抗作用

目的　研究过氧化氢 (H2 O2 )对心肌细胞[Ca2 + ]i的影响 ,以及卡维地洛对H2 O2 诱导钙超载的拮抗作用。方法　采用SD大鼠乳鼠进行心肌细胞培养。实验分为 4组 :正常对照组 ;H2 O2 组 :加入终浓度为 10 0 μmol/L的H2 O2 ;卡维地洛组 :加入终浓度为 1μmol/L的卡维地洛 ;H2 O2 +卡维地洛组 :同时加入卡维地洛 1μmol/L与H2 O2 10 0 μmol/L。以Fluo 3/AM荧光指示剂负载 ,应用激光共聚焦显微镜技术 ,分别于加入H2 O2 后即刻和 15min时检测 [Ca2 + ]i的变化。结果　对照组和卡维地洛组心肌细胞内荧光强度和荧光光密度值较低。一加入H2 O2 ,细胞内荧光光密度值便开始增加 ,15min后细胞内荧光强度和荧光光密度值较对照组显著增高 (P <0 0 5 )。而H2 O2 +卡维地洛组细胞内荧光光密度值显著低于H2 O2 组 (P <0 0 5 )。结论　H2 O2 可引起心肌细胞内钙超载 ,卡维地洛能显著减轻H2 O2 诱导的心肌细胞内Ca2 + 超载     

黄连素对乳腺癌细胞生长、迁移和放射敏感性的影响

目的 研究黄连素对乳腺癌细胞生长、迁移和放射敏感性的影响.方法 选取人乳腺癌细胞MDA-MB-231和MCF-7,用MTT法检测细胞的生长和增殖;划痕愈合法观察细胞迁移能力;细胞流式技术测定细胞周期改变;磷脂酰丝氨酸外翻分析法检测细胞凋亡;Western blot法测定蛋白表达水平;细胞克隆形成法观察黄连素与辐射的联合作用.结果 黄连素明显抑制人乳腺癌MCF-7和MDA-MB-231细胞的生长,并显现剂量-效应和时间-效应关系,MCF-7和MDA-MB-231细胞对黄连素表现出同样的敏感性.黄连素可以诱导剂量依赖性的G0/G1期细胞阻滞,40 μmol/L的黄连素处理后MDA-MB-231和MCF-7细胞早期凋亡分别高达86.63％和66.62％,与未处理的对照组相比,差异均有统计学意义(t=75.15和43.75,P＜0.01).黄连素明显降低了细胞周期调节相关蛋白Cyclin B1和抑凋亡蛋白Bcl-2的表达水平,而增加了促凋亡蛋白Bax和Caspase-3的表达水平,但不影响细胞周期调节蛋白Cyclin D1的表达水平.低剂量(≤5μmol/L)黄连素可以明显降低细胞的迁移能力.采用单靶多击模型拟合曲线发现,与单独照射组相比,5 μmol/L黄连素预处理4h后MDA-MB-231细胞和MCF-7细胞的辐射增敏比分别为1.12和1.22.结论 黄连素通过调节细胞凋亡和细胞周期阻滞抑制乳腺癌细胞生长和迁移,并可提高乳腺癌细胞的放射敏感性.     

溶酶体膜通透化在铀诱导肾近端小管上皮细胞死亡中的作用及机制

目的:探究铀(Uranium, U)暴露诱导人肾近端小管上皮HK-2细胞溶酶体膜通透化(LMP)致细胞死亡的作用及机制。方法:以100、300、600 μmol/L铀染毒HK-2细胞24 h,分别采用DCFH-DA荧光探针法和MitoSOX荧光探针法检测不同浓度铀染毒的HK-2细胞内氧自由基(reactive oxyg...     

乳腺癌患者婆罗双树样基因4表达情况及PTEN/AKT/mTOR通路对乳腺癌阿霉素耐药性作用研究

目的探讨乳腺癌患者婆罗双树样基因4(SALL4)的表达情况,以及PTEN/AKT/mTOR通路对乳腺癌阿霉素耐药性的作用。方法选取海南省人民医院自2010年6月至2022年6月收治的90例乳腺癌手术患者为研究对象并提取患者乳腺癌组织及癌旁组织。采用免疫组织化学法检测乳腺癌组织的SALL4表达情况,计算阳性表达率。采用Western Blot和荧光定量聚合酶链反应法检测SALL4蛋白表达和mRNA表达。采用阿霉素处理人乳腺癌细胞MCF-7、其阿霉素耐药细胞MCF-7/ADR以及在MCF-7/ADR细胞中沉默SALL4构建的shSALL4-MCF-7/ADR细胞三种细胞,采用MTT法检测处理24、48 h后的IC50。采用Western Blot法检测MCF-7、MCF-7/ADR、shSALL4-MCF-7/ADR细胞的PTEN、p-AKT、AKT、p-mTOR、mTOR蛋白相对表达量。比较乳腺癌及癌旁组织中的SALL4表达水平,不同病理特征乳腺癌患者的SALL4表达阳性率;分析SALL4对乳腺癌细胞阿霉素耐药性及PTEN/AKT/mTOR通路的影响。结果90例患者中,SALL4表达阳性34例,阳性表达率为37.78%(34/90)。乳腺癌组织中SALL4蛋白相对表达水平和SALL4 mRNA相对表达水平均高于癌旁组织,差异有统计学意义(P<0.05)。不同年龄、病理类型、组织学分级、肿瘤大小及雌激素受体、孕激素受体、人表皮生长因子受体、Ki67表达患者的SALL4表达阳性率比较,差异无统计学意义(P>0.05);有淋巴结转移患者的SALL4表达阳性率高于无淋巴结转移患者,差异有统计学意义(P<0.05)。阿霉素处理24、48 h后的MCF-7/ADR细胞的IC50均高于MCF-7细胞,差异有统计学意义(P<0.05);在MCF-7/ADR细胞中沉默SALL424、48 h后的shSALL4-MCF-7/ADR细胞的IC50均较MCF-7/ADR细胞降低,差异有统计学意义(P<0.05)。MCF-7/ADR细胞的PTEN蛋白表达低于MCF-7细胞,p-AKT和p-mTOR蛋白表达高于MCF-7细胞,差异有统计学意义(P<0.05);沉默SALL4后,shSALL4-MCF-7/ADR细胞的PTEN蛋白表达升高,高于MCF-7/ADR细胞,p-AKT和p-mTOR蛋白表达下降,低于MCF-7/ADR细胞,差异有统计学意义(P<0.05)。结论SALL4在乳腺癌组织中的表达高于癌旁组织,且与淋巴结转移明显相关。沉默SALL4可抑制乳腺癌细胞的增殖活性,降低阿霉素的耐药性,且SALL4对乳腺癌细胞阿霉素耐药性的影响与PTEN/AKT/mTOR通路有关。     

Comparison of photodynamic treatment produced cell damage between human breast cancer cell MCF-7 and its multidrug resistance cell

BackgroundMultidrug resistance (MDR) of breast cancer is a major obstacle in chemotherapy of cancer treatments. Recently the anti-tumor effects of Chlorin e6 (Ce6) mediated photodynamic therapy (Ce6-PDT) were reported in skin cancer and hepatoma in vitro. However, its therapeutic potential in killing human breast cancer especially those with MDR and the differences between MCF-7 and MCF-7/ADR after PDT treatment has not been fully investigated.MethodsMTT assay was used to measure cell survival rate of MCF-7 cells and MCF-7/ADR cells. Intracellular reactive oxygen species (ROS) generation was measured by monitoring the fluorescence intensity of dichlorofluorescein (DCF) by flow cytometry. Nuclear morphology changes and DNA damage in both MCF-7 and MCF-7/ADR after Ce6-PDT were analyzed by hochest33342 staining and comet assay. Western blot and monodansylcadaverine (MDC) staining were used to monitor autophagic response in MCF-7/ADR.ResultsCe6-PDT induced cell viability decrease, intracellular ROS generation, and DNA damage in concentration-dependent and cell-specific manner, and MCF-7 was more sensitive to Ce6-PDT than MCF-7/ADR cells at the same PDT condition. PDT treatment could trigger cell death via apoptosis in MCF-7 cells but autophagic cell death in MCF-7/ADR cells.ConclusionThese results suggested that MCF-7 was more sensitive to Ce6-PDT than MCF-7/ADR, and PDT treatment could trigger apoptotic response in MCF-7 cells, but stimulate autophagic response in MCF-7/ADR cells.     

Study of tea polyphenol as a reversal agent for carcinoma cell lines' multidrug resistance (study of TP as a MDR reversal agent)

The aim of this study was to examine MDR1 expression product P-glycoprotein (Pgp) and study the effect and mechanism of tea polyphenol (TP) in reversion of multidrug resistance (MDR) in carcinoma cell lines. Immunocytochemical method was used for qualitative detection of Pgp. A comparative study of cytotoxicity and multidrug resistance reversion effect was made by MTT assay for tea polyphenol and quinidine in MCF-7 and MCF-7/Adr cell lines. The multidrug resistance reversion effect and mechanism were studied by measuring the uptake of 99mTc-tetrofosmin in the carcinoma cell lines. (1) The Pgp overexpression in MCF-7/Adr cells was found to be strong positive, while the Pgp expression of MCF-7 was negative. (2) Although both tea polyphenol and quinidine could not remarkably change the toxicity of adriamycin to MCF-7, they could improve the sensitivity of MCF-7/Adr to adriamycin. The reversion index of tea polyphenol and quinidine was 3 and 10 respectively. (3) The cellular uptake of 99mTc-tetrofosmin was remarkably lower in MCF-7/Adr than in MCF-7. The uptake of 99mTc-tetrofosmin in MCF-7/Adr exhibited a 4, 13, 16 fold increase in the presence of 200, 400 and 500 microg/ml of tea polyphenol respectively. The uptake of 99mTc-tetrofosmin in MCF-7/Adr exhibited only a 4-fold increase in the presence of 200 microM of quinidine. Immunocytochemistry can detect P-glycoprotein expression level qualitatively. Tea polyphenol is not only an anti-tumor agent, but also a multidrug resistant modulator similar to quinidine. The multidrug resistance reversion mechanism of tea polyphenol seems to be its inhibition of the activity of P-glycoprotein. Tea polyphenol has the advantage of very low toxicity in tumor treatment.     

Doxorubicin-mediated free radical generation in intact human tumor cells enhances nitroxide electron paramagnetic resonance absorption intensity decay

The decay of nitroxide spin label electron paramagnetic resonance (EPR) absorption intensity was used to investigate the doxorubicin-mediated intracellular generation of free radicals. The effects of 50–500 μg/ml doxorubicin on human tumor cells (MCF-7, breast cancer cells, and HL-60, promyelocytic leukemia, cells) were studied by measuring 2,2,6,64etramethylpip-eridine-1-oxyl (TEMPO) absorption intensity decay (TAID) at a TEMPO concentration of 10 μM. Doxorubicin accelerated the TAID in both cell lines with a detection limit of 50 μg/ml for MCF-7 cells and 500 μg/ml doxorubicin for HL-60 cells. Preincubation of cells with the iron chelating agent, deferoxamine (5 mM), partially prevented the effects of doxorubicin on the TAID. Catalase and copper, zinc-superoxide dismutase (Cu, Zn-SOD) had no influence on the effects of doxorubicin on the TAID in intact cells. However, Cu, Zn-SOD completely abolished the effects of doxorubicin on the TAID in a MCF-7 cell-free system. Our findings suggest that doxorubicin mediates the intracellular generation of O₂ and that iron is involved in this process.     

Exendin-4介导的猪髋动脉内皮细胞NO释放与细胞内钙离子浓度变化的关系

目的 观察Exendin-4(Ex-4)介导的猪髋动脉内皮细胞(PIEC)内一氧化氮(NO)释放与钙离子变化的关系,探讨Ex-4影响内皮细胞功能的机制.方法 免疫荧光法检测确认PIEC上存在胰高血糖素样肽-1受体(GLP-IR).NO荧光探针(DAF-FM DA)标记细胞内NO,荧光酶标仪检测Ex-4作用内皮细胞后不同时间点[加药前(0h),加药后l、2、3、4、5、6、7、8、9、10、11、12h,共13个时点]细胞内NO释放情况;钙离子荧光探针(Fura-2 AM)标记细胞内钙,荧光酶标仪检测细胞内3个不同时段(0～30min,4～4.5h,8～8.5h)钙浓度变化情况;评价Ex-4诱导PIEC释放NO与细胞内钙的关系.结果　PIEC上有GLP-1R表达.Ex-4引起PIEC内NO增加,且有时间依赖关系,与0h比较,4h开始NO明显增高(P＜0.05),8h时细胞内NO含量较其他各时点均明显增高(P＜0.05).Ex-4干预后0～30min、4～4.5h和8～8.5h 3个时段细胞内钙均较对照组高(2.042±2.115 vs 0.634±0.352,P＜0.01;0.413±0.154 vs 0.113±0.111,P＜0.01;0.309±0.133 vs 0.063±0.120,P＜0.01).Ex-4干预PIEC后NO释放前期前段(0～30min),细胞内钙逐渐上升(拟合曲线:y=0.106x+l.326); NO释放中期前段(4～4.5h,y=0.003x+0.374)和NO释放后期前段(8～8.5h,y=-0.001x+0.324)细胞内钙浓度虽同NO一样也高于对照组,但没有明显的变化趋势.结论 Ex-4可增加内皮细胞内NO释放,该过程与细胞内钙变化密切相关.     

Comparative 99mTc-sestamibi and 3H-daunomycin uptake in human carcinoma cells: relation to the MDR phenotype and effects of reversing agents.

Because 99mTc-sestamibi (MIBI) appears to be a potent candidate for multidrug resistance (MDR) evaluation in tumors, its cellular uptake should be similar to that of 3H-daunomycin in a variety of conditions of expression and inhibition of MDR activity. METHODS: We used a human rhinopharyngeal carcinoma cell line (KB-3-1) and its MDR variant (KB-A1). Cells were incubated 2 h with 99mTc-MIBI and 3H-daunomycin under control conditions or in the presence of a reversing agent such as verapamil (10 pmol/L), PSC833 (1 micromol/L) or S9788 (5 micromol/L). RESULTS: Relative to the KB-3-1-sensitive cells, accumulations of 99mTc-MIBI and 3H-daunomycin were reduced to 31% +/- 5% and 36% +/- 11% (P < 0.001 for both) in KB-A1-resistant cells. In sensitive cells, accumulation of both agents was increased by verapamil and PSC833 (range 115%-140%; P < 0.05) but not by S9788. In KB-A1 cells, only S9788 significantly increased the cellular uptake of 99mTc-MIBI (138% +/- 25%; P < 0.01), whereas the intracellular uptake of 3H-daunomycin was markedly increased with the three reversing agents (up to 311% +/- 37% with S9788; P < 0.001). With this last treatment, uptake of 3H-daunomycin in KB-A1 cells nearly returned to its basal level in sensitive cells. CONCLUSION: 99mTc-MIBI monitors the MDR phenotype of tumor cells effectively but responds to reversing agents differently than 3H-daunomycin.     

肿瘤耐药相关鞘糖脂CMH对人树突状细胞B7表达的影响

为了探讨肿瘤耐药相关鞘糖脂CMH在耐药肿瘤细胞免疫逃避中的作用,用柱层析的方法分离纯化了KBv200细胞的耐药相关中性鞘糖脂CMH,采用流式细胞仪技术检测CMH作用前后人树突状细胞（DC）B7抗原的表达。结果显示,CMH明显地抑制DC B7抗原的表达,说明肿瘤耐药相关鞘糖脂可能是通过对DC的影响而抑制机体的免疫反应。     

胆碱能激动剂引起的前庭毛细胞内钙离子浓度升高及庆大霉素对它的影响

目的 通过观察胆碱能受体激动剂对离体前庭毛细胞内钙离子浓度的影响,以探讨前庭毛细胞膜所存在的胆碱能受体分型及庆大霉素对钙离子通道的阻断作用。方法 用胶原酶消化后机械分离法,分离豚鼠前庭毛细胞（VHC）,钙敏荧光探针Fluo-3染色,用激光扫描共聚焦显微镜记录VHC的钙荧光图像及细胞内游离钙离子浓度（[Ca^2 ]i）的动态变化。结果 ①胆碱能M和N型受体激动剂乙酰胆碱（ACh）、氨甲酰胆碱（CCh）均可引起离体VHC内[Ca^2 ]i的升高;N型受体激动剂化乙酰胆碱（ACh-Br)仅在高浓度（10mmol/L）时引起部分（4／5个）离体CHC内[Ca^2 ]i升高,在低浓度（1mmol/L）时影响不明显;②阿托品对ACh、CCh引起的VHC内[Ca^2 ]i的升高有抑制作用;加入0．1mmol/L阿托品可使1mmol/LACh或CCh引起的VHC内[Ca62 ]i升高的峰值明显减小（P＜0．01）;③0．1mmol／LACh引起VHC内[Ca^2 ]i升高之后,再加入0．5mmol／L庆在霉素,VHC内[Ca^2 ]i出现显著下降,至低于静息时的水平。结论 豚鼠壶腹嵴前庭毛细胞膜上存在M型和N型两种受体,M型受体激动剂引起VHC内[Ca^2 ]i的升高较N型明显。阿托品对M型受体激动剂引起的[Ca^2 ]i升高有抑制作用大;庆大霉素对前庭毛细胞膜的钙离子通道可能有阻滞作用。