PTEN抑制乳腺癌细胞MDA-MB-231体外增殖及其机制的探讨

目的:观察PTEN对乳腺癌细胞MDA-MB-231体外增殖和迁移的影响,进一步探讨其可能机制.方法:选用人乳腺癌细胞MDA-MB-231并体外培养,质粒转染技术建立过表达PTEN的稳定细胞株MDA-MB-231/PTEN作为实验组,空载体细胞株MDA-MB-231/pcDNA3.1作为阴性对照组,以未转染细胞为正常对照组,RT-PCR检测各组细胞PTEN的表达水平,MTT法检测各组MDA-MB-231细胞的增殖能力,Transwell小室迁移实验检测各组MDA-MB-231细胞的迁移能力.结果:PTEN在MDA-MB-231/PTEN细胞中表达稳定,且其表达量明显高于阴性对照组和正常对照组,而阴性对照组和正常对照组PTEN表达量差异无统计学意义.转染PTEN基因可显著抑制乳腺癌细胞MDA-MB-231的增殖和迁移能力.结论:PTEN与乳腺癌的增殖和迁移有关,对乳腺癌细胞的体外增殖和迁移能力起到抑制作用.     

Effect of TIMP1 Gene in Proliferation of Human Colon Carcinoma Cells

目的 采用体外试验探讨基质金属蛋白酶抑制剂1(TIMP1)基因对人结肠癌(HCT-8)细胞增殖的影响.方法 构建TIMP1基因的真核表达载体和RNA干扰质粒(pcDNA3.1-TIMP1-K、TIMP1 RNAi、pcDNA3.1和空白对照),将TIMP1基因真核表达质粒和RNA干扰质粒分别瞬时转染入HCT-8细胞48～72h后,采用Real TimePCR方法检测TIMP1基因在HCT-8细胞中基因转录表达水平,并用Western blot方法检测TIMP1基因在HCT-8细胞中蛋白表达水平,采用MTr试验检测TIMP1基因过表达和干扰后对HCT-8细胞增殖的影响.结果 成功构建了TIMP1真核表达质粒和RNA干扰质粒.与空白对照比较,质粒pcDNA3.1-TIMP1-K在HCT-8细胞中mRNA和蛋白的相对表达含量较高,质粒TIMP1 RNAi的mRNA和蛋白表达含量较低,差异均有统计学意义(P＜0.05).构建过表达质粒(pcDNA3.1-TIMP1-K)转染HCT-8细胞后,与空白对照相比,第1～4天HCT-8细胞的活性无显著变化(P＞0.05),第5～7天TIMP1基因过表达能够促进HCT-8细胞的增殖活性(P＜0.05);构建干扰质粒(TIMP1 RNAi)转染HCT-8细胞后,与空白对照相比,第1～4天HCT-8细胞生长无显著变化(P＞0.05),第5～7天TIMP1基因过表达能够抑制HCT-8细胞增殖(P＜0.05).结论 TIMP1基因过表达后能够促进人结肠癌细胞的增殖,在一定条件下还能够抑制人结肠癌细胞的增殖.     

小干扰RNA技术对沉默乳腺细胞中DEK基因的表达及乳腺癌细胞增殖与凋亡的影响

目的探讨小干扰RNA技术对沉默乳腺细胞中DEK基因的表达及乳腺癌细胞增殖与凋亡的影响,为乳腺癌的分子诊断及靶向治疗奠定理论基础。方法以人类正常乳腺癌细胞系Hs578Bst作为对照,蛋白质印迹(Western bloting)检测MCF-7、T47D、MDA-MB-231、BT549乳腺癌细胞中DEK蛋白表达;MCF-7细胞分为空白组、阴性对照组、DEK转染组,转染48 h后,Western bloting检测DEK、活化的含半胱氨酸的天冬氨酸蛋白水解酶3(Cleaved Caspase-3)、Notch1、Hes1蛋白表达;CCK8实验和流式细胞术分别检测细胞的增殖及凋亡情况。结果 DEK基因在MCF-7、T47D、MDA-MB-231、BT549细胞中的相对表达量均显著高于Hs578Bst,差异有统计学意义(均P0.01);RNA干扰可显著降低乳腺癌细胞DEK的蛋白相对表达量;阴性对照组细胞存活率、细胞凋亡率及Cleaved caspase-3、Notch1、Hes1蛋白相对表达量与空白组差异无统计学意义(均P0.05),DEK转染组细胞存活率及Notch1、Hes1蛋白相对表达量显著低于空白组,细胞凋亡率及Cleaved caspase-3蛋白相对表达量显著高于空白组,差异有统计学意义(均P0.01)。结论抑制乳腺癌细胞DEK基因表达可显著降低癌细胞的增殖及诱导细胞凋亡,其作用机制可能与下调Notch1信号通路有关。     

TIMP1基因对人结肠癌HCT-8细胞增殖影响的研究

目的采用体外试验探讨基质金属蛋白酶抑制剂1(TIMP1)基因对人结肠癌(HCT-8)细胞增殖的影响。方法构建TIMP1基因的真核表达载体和RNA干扰质粒(pcDNA3.1-TIMP1-K、TIMP1 RNAi、pcDNA3.1和空白对照),将TIMP1基因真核表达质粒和RNA干扰质粒分别瞬时转染入HCT-8细胞48～72 h后,采用Real Time PCR方法检测TIMP1基因在HCT-8细胞中基因转录表达水平,并用Western blot方法检测TIMP1基因在HCT-8细胞中蛋白表达水平,采用MTT试验检测TIMP1基因过表达和干扰后对HCT-8细胞增殖的影响。结果成功构建了TIMP1真核表达质粒和RNA干扰质粒。与空白对照比较,质粒pcDNA3.1-TIMP1-K在HCT-8细胞中mRNA和蛋白的相对表达含量较高,质粒TIMP1 RNAi的mRNA和蛋白表达含量较低,差异均有统计学意义(P<0.05)。构建过表达质粒(pcDNA3.1-TIMP1-K)转染HCT-8细胞后,与空白对照相比,第1～4天HCT-8细胞的活性无显著变化(P>0.05),第5～7天TIMP1基因过表达能够促进HCT-8细胞的增殖活性(P<0.05);构建干扰质粒(TIMP1 RNAi)转染HCT-8细胞后,与空白对照相比,第1～4天HCT-8细胞生长无显著变化(P>0.05),第5～7天TIMP1基因过表达能够抑制HCT-8细胞增殖(P<0.05)。结论 TIMP1基因过表达后能够促进人结肠癌细胞的增殖,在一定条件下还能够抑制人结肠癌细胞的增殖。     

自噬基因Beclin1过表达诱导人卵巢癌细胞SKOV3自噬和凋亡的研究

目的:探讨自噬基因Beclin 1在人卵巢癌SKOV3细胞中过表达对其体外生长活性的影响。方法:构建自噬基因Beclin 1的真核表达载体pcDNA3.1/Beclin1,将其稳定转染SKOV3细胞,实现Beclin 1在SKOV3中的过表达;用MTT法分析Beclin1过表达对SKOV3增殖的影响,用流式细胞仪检测凋亡和自噬情况,电镜和荧光显微镜下观察自噬现象。结果:pcD-NA3.1/Beclin1转染SKOV3细胞后Beclin 1在mRNA和蛋白水平均高于空质粒pcDNA3.1转染组和未转染组。Beclin 1在SKOV3中的稳定过表达后G1期细胞明显增多,S期细胞比例明显减少,细胞增殖受到抑制,凋亡率为(21.26±3.89)%,高于空质粒pcDNA3.1转染组和未转染组,差异有统计学意义(P<0.05);流式细胞仪检测pcDNA3.1/Beclin1转染SKOV3细胞后MDC标记的自噬囊泡平均荧光强度高于pcDNA3.1转染组和未转染组。pcDNA3.1/Beclin1转染SKOV3细胞后在电镜下可见大量自噬囊泡形成。在荧光显微镜下见pcDNA3.1/Beclin1转染后SKOV3细胞中MDC标记的自噬囊泡明显增加。结论:自噬基因Beclin1过表达可诱导人卵巢癌细胞SKOV3自噬和凋亡,针对自噬基因Beclin1的卵巢癌基因治疗可能具有可行性。     

过表达PTEN对SKOV3和SKOV3-ADM细胞增殖的影响

目的:研究过表达PTEN对卵巢癌细胞SKOV3和卵巢癌耐药细胞株SKOV3-ADM增殖能力的影响。方法:构建PTEN真核表达载体,采用脂质体转染技术转染入SKOV3及SKOV3-ADM细胞,采用RT-PCR和Western-blot检测PTEN基因及蛋白表达水平的变化,判断转染效果;MTT法检测细胞增殖速率变化。结果:转染PTEN表达载体至SKOV3及SKOV3-ADM细胞后,RT-PCR及Western-Blot实验证实SKOV3和SKOV3-ADM细胞中PTEN基因及蛋白表达水平明显上调。MTT结果显示,上调PTEN表达后的SKOV3和SKOV3-ADM细胞相对于空白和阴性对照组,细胞的体外增殖能力明显减弱(P<0.01)。结论:PTEN蛋白在卵巢癌的发生发展过程中起着抑制作用,可能成为一种新的肿瘤分子治疗手段。     

OPN反义基因对乳腺癌MDA-MB-231细胞迁移能力的影响

目的:探讨OPN反义基因(ANOPN)对人乳腺癌细胞系MDA-MB-231细胞生长及迁移能力的影响。方法:构建人骨桥蛋白反义基因真核表达质粒pcDNA3.1-ANOPN,将质粒pcDNA3.1-ANOPN、空载体pcDNA3.1(+)和等量的脂质体分别转染人乳腺癌细胞系MDA-MB-231,将转染细胞分别命名为MDA-ANOPN、MDA-vect和MDA,在体外观察各组细胞的迁移能力。结果:MDA-MB-231细胞比MDA-vect及MDA细胞迁移能力弱(P<0.01)。结论:ANOPN可抑制人乳腺癌细胞系MDA-MB-231细胞的迁移能力。     

单纯疱疹病毒II型gD糖蛋白在真核细胞中的表达

目的:构建真核表达质粒pcDNA3/gD,并在体外COS-7细胞中进行表达。方法:体外PCR扩增出gD糖蛋白基因,克隆入真核表达质粒pcDNA3中。PCR、酶切和测序证实插入的gD基因正确后,转染COS-7细胞,用原位ELISA鉴定表达蛋白。结果:构建了pcDNA3/gD真核表达质粒,经原位ELISA证实,转染COS-7细胞表达的gD蛋白能和gD单克隆抗体ID3和DL11结合,证明该蛋白具有天然gD蛋白的抗原性。结论:构建的重组真核表达质粒pcDNA3/gD能够在COS-7细胞中表达。     

戊型肝炎病毒ORF3基因转染HeLa细胞及其稳定表达

目的 将戊型肝炎病毒ORF3基因转染HeLa细胞,建立能稳定表达ORF3蛋白(pORF3)的细胞株.方法 将ORF3基因片段克隆至真核表达质粒pcDNA3,构建重组质粒pcDNA3-ORF3.电穿孔法将其导入HeLa细胞中,G418筛选得到稳定抗性的细胞株,并用RT-PCR和Western印迹法分别从mRNA水平和蛋白水平检测ORF3的表达.结果 成功构建了重组表达质粒pcDNA3-ORF3,并筛选获得能稳定表达pORF3蛋白的HeLa细胞株.结论 pORF3蛋白能够在HeLa细胞中稳定表达,为进一步研究其生物学功能奠定了实验基础.     

单纯疱疹病毒Ⅱ型gD糖蛋白在真核细胞中的表达

目的：构建真核表达质粒pcDNA3／gD，并在体外COS-7细胞中进行表达。方法：体外PCR扩增出gD糖蛋白基因，克隆入真核表达质粒pcDNA3中。PCR、酶切和测序证实插入的gD基因正确后，转染COS-7细胞，用原位ELISA鉴定表达蛋白。结果：构建了pcDNA3／gD真核表达质粒，经原位ELISA证实，转染，COS-7细胞表达的gD蛋白能和gD单克隆抗体ID3和DL11结合，证明该蛋白具有天然gD蛋白的抗原性。结论：柯建的重组真核表达质粒pcDNA3／gD能够在COS-7细胞中表达。     

Soft cell

A shake-up in the healthcare system at the western world's largest remand centre in New York City means sick prisoners are better off in jail, reports Peter Mason.     

Antimicrobial agents targeting bacterial cell walls and cell membranes

Antimicrobial agents that target the bacterial cell wall or cell membrane have been used effectively for the past 70 years. Among the agents that inhibit bacterial cell wall synthesis, the beta-lactam antibiotics have emerged into broad-spectrum agents that inhibit most pathogenic bacteria, but are now being threatened by the rapid spread of drug-inactivating beta-lactamases. Glycopeptides still retain high activity against staphylococci, but resistance among the enterococci has become a major problem. Recently, fosfomycin has been used in the treatment of multidrug-resistant Gram-negative bacteria. Daptomycin, which targets both membrane function and peptidoglycan synthesis, is especially effective in treating staphylococcal infections. The polymyxin antibiotics that target cell membranes are being used more frequently to treat multidrug-resistant Gram-negative infections. The ionophore antibiotics, used in veterinary medicine, target membranes in many microbial and animal species. Although increasing resistance is a continuing concern, these classes of bactericidal agents can provide highly effective antibiotics.     

Effect of methionine-deprived nutrition on cell growth and cell kinetics in cell cultures and experimental tumors

The effect of methionine-deprived nutrition on cell growth and cell kinetics was investigated in cell cultures and in tumor-bearing rats using the total parenteral nutrition (TPN) technique. A simultaneous flow cytometric measurement of the cellular DNA content and the amount of 5-bromodeoxyuridine incorporated into cellular DNA was performed for analysis of cell kinetics. The methionine-free medium demonstrated a cytocidal effect on the growth of SLC cells after 6 hours of culturing. It decreased viability from 80% in the control medium to 23%, and it decreased the S phase and increased the G0/G1 phase of the cell cycles. The methionine-deprived medium showed a concentration-dependent inhibition in cellular growth. Methionine-deprived TPN was seen to inhibit AH109A and SLC tumor growth compared with conventional TPN and decreased the S phase and increased the G0/G1 phase of cell cycles. These results confirm that methionine deprivation blocks cells from processing into the G1 phase and recycling, and that it is effective in inhibiting tumor growth in cultures and in vivo.     

亚砷酸钠对HaCaT细胞增殖周期及ROS生成影响

目的 探讨亚砷酸钠(NaAsO₂)对人皮肤角质形成细胞(HaCaT)增殖、细胞周期及活性氧(ROS)生成影响。方法 以0、25、50μmol/L NaAsO₂作用于HaCaT细胞6 h后,以Alamar Blue还原法检测细胞增殖水平;以流式细胞仪检测细胞周期及ROS水平。结果 25、50μmol/L NaAsO₂组细胞增殖水平分别为(93.5±1.18)%、(82.9±2.64)%,明显低于对照组(100±0.51)%(P<0.05);G2/M期细胞数分别为(19.15±0.29)%、(18.12±1.35)%,明显高于对照组(15.24±0.04)%(P<0.05);ROS水平分别为(128.61±6.23)%、(152.92±7.25)%,明显高于对照组(100.00±3.45)%(P<0.05)。结论 NaAsO₂作用可引起HaCaT细胞ROS含量增高,同时G2/M期细胞数增多,但G2/M期细胞比例增高并不是由细胞增殖作用所引起。     

硫酸铟对L929细胞周期及细胞凋亡的影响

目的探讨硫酸铟对小鼠成纤维细胞(L929)细胞周期和细胞凋亡的影响。方法用四氮唑蓝比色法(MTT),检测L929的存活情况;采用流式细胞仪检测硫酸铟对L929细胞周期、细胞凋亡(染毒浓度分别为1.5、3.0、4.5mmol/L,染毒时间为24h)的影响。结果硫酸铟可改变L929细胞周期及细胞凋亡率。细胞周期表现为S期细胞增多,而处于G1期的细胞减少,提示硫酸铟可能具有影响L929细胞周期的作用,进而抑制细胞增殖;硫酸铟可增加细胞凋亡率。结论硫酸铟可引起L929细胞毒性,细胞存活率呈浓度-时间依赖性下降;硫酸铟可影响细胞周期和诱导细胞凋亡。     

Genistein-induced cell cycle arrest and apoptosis in a head and neck squamous cell carcinoma cell line.

Epidemiological studies have shown a lower incidence of breast, prostate, and colon cancers in Asian countries, particularly China and Japan, than in the United States. It is believed that genistein, a natural tyrosine kinase inhibitor and a metabolite of soy products, may be responsible for the protection from these cancers. Genistein was shown to inhibit cell proliferation and to induce cell cycle arrest at the G2-M phase in breast, prostate, and jurkat T cell leukemia cell lines. However, such studies have not been reported in squamous cell cancers of the head and neck. In this report, we show that genistein inhibits proliferation of a squamous cell carcinoma cell line HN4. Additionally, genistein caused cell cycle arrest at the S/G2-M phase and induced programmed cell death (apoptosis) in these cells. These effects appear to be dose and time dependent, irreversible, persisting when the cells were recultured in genistein-free medium for up to 72 hours, and specific for tumor cells, because genistein did not affect normal keratinocytes. These results suggest that if genistein shows similar results in clinical trials, it can be a potential chemopreventive/chemotherapeutic agent for cancers of the head and neck.     

Sickle cell disease

The sickle cell gene is present in about 10 per cent of the British black population. Thus, the diagnosis and management of all the complications of sickle cell disease are of increasing importance.