Induction of altered c-src product during neural differentiation of embryonal carcinoma cells

The expression of the cellular src gene product pp60c-src was examined in an embryonal carcinoma cell line that differentiates in vitro into neuronlike cells after being treated with retinoic acid. Quantitative and qualitative changes in c-src expression accompanied the events associated with neuronal differentiation. The levels of pp60c-src increased 8- to 20-fold during the period when the cells elaborated neuritic processes and expressed neuron-specific proteins. The electrophoretic mobility of pp60c-src induced in these cells was retarded in comparison with that in untreated cells or in treated cells before neurite elaboration. The shift in electrophoretic mobility was due to an alteration in the amino terminal 16,000 daltons of pp60c-src and similar to an alteration of c-src protein found in neural tissues and in pure primary cultures of neuronal cells. These results indicate that expression of pp60c-src induced by retinoic acid in these embryonal carcinoma cells mimics the expression of c-src in developing neurons. Therefore, this embryonal carcinoma cell line provides a model system to investigate the function of the src protein in neuronal differentiation.     

Molecular cloning of the complementary DNA for human tumor necrosis factor

Tumor necrosis factor (TNF) is a soluble protein that causes damage to tumor cells but has no effect on normal cells. Human TNF was purified to apparent homogeneity as a 17.3-kilodalton protein from HL-60 leukemia cells and showed cytotoxic and cytostatic activities against various human tumor cell lines. The amino acid sequence was determined for the amino terminal end of the purified protein, and oligodeoxyribonucleotide probes were synthesized on the basis of this sequence. Complementary DNA (cDNA) encoding human TNF was cloned from induced HL-60 messenger RNA and was confirmed by hybrid-selection assay, direct expression in COS-7 cells, and nucleotide sequence analysis. The human TNF cDNA is 1585 base pairs in length and encodes a protein of 233 amino acids. The mature protein begins at residue 77, leaving a long leader sequence of 76 amino acids. Expression of high levels of human TNF in Escherichia coli was accomplished under control of the bacteriophage lambda PL promoter and gene N ribosome binding site.     

地塞米松与肝素对HL－60细胞增值和生物大分子合成的影响

用地塞米松（Ｄｅｘ）和肝素（Ｈｅｐ）Ｉｃ６０及Ｉｃ５０低一个剂量，对ＨＬ－６０细胞增殖、生长曲线和分裂指数均有明显的抑制作用，联合应用时抑制作用显著增强；对ＤＮＡ和蛋白质合成抑制作用大于ＲＮＡ，联合应用抑制作用均显著增强，提示两药抑制ＨＬ－６０细胞增殖、分裂和生长可能与它们抑制ＤＮＡ和蛋白质合成有关，亦与抑制ＲＮＡ合成有一定关系。     

Purified human granulocyte-macrophage colony-stimulating factor: direct action on neutrophils

Neutrophil migration inhibition factor from T lymphocytes (NIF-T) is a lymphokine that acts to localize granulocytes. Medium conditioned by the Mo human T-lymphoblast cell line was used to purify NIF-T, a glycoprotein with a molecular weight of 22,000. The NIF-T was found to potently stimulate the growth of granulocyte and macrophage colonies from human bone marrow and colony formation by the KG-1 myeloid leukemia cell line. Thus a human lymphokine (NIF-T) that modulates the activities of mature neutrophilic granulocytes is also a colony-stimulating factor acting on precursors to induce growth and differentiation of new effector cells.     

银杏叶多糖抑制人白血病细胞增殖的试验研究

[目的]明确银杏叶多糖(PGBL)对白血病的治疗价值。[方法]以干燥银杏叶为材料,提取PGBL;向100μl对数增长期的人急性早幼粒白血病HL-60细胞悬液中分别加入100μl含PGBL50、100、200μg/ml的RPMI-1640培养液,以加入100μlRPMI-1640纯培养液为对照,研究不同浓度(50、100、200μg/ml)PGBL对HL-60细胞增殖的抑制率。[结果]50、100、200μg/ml PGBL对人急性早幼粒白血病HL-60细胞增殖均有不同程度的抑制作用,且随着药物浓度和作用时间的增加,抑制作用增强,即PGBL对HL-60细胞增殖的抑制作用存在剂量-时间依赖性;方差分析结果表明,PGBL对HL-60细胞增殖的抑制率显著高于对照(P<0.01)。[结论]PGBL对HL-60细胞增殖具有较好的抑制作用,且该抑制作用具有浓度-时间依赖性。     

Cell cycle-dependent regulation of phosphorylation of the human retinoblastoma gene product

The human retinoblastoma gene (RB1) encodes a protein (Rb) of 105 kilodaltons that can be phosphorylated. Analysis of Rb metabolism has shown that the protein has a half-life of more than 10 hours and is synthesized at all phases of the cell cycle. Newly synthesized Rb is not extensively phosphorylated (it is "underphosphorylated") in cells in the G0 and G1 phases but is phosphorylated at multiple sites at the G1/S boundary and in S phase. HL-60 cells that were induced to terminally differentiate by various chemicals lost their ability to phosphorylate newly synthesized Rb at multiple sites when cell growth was arrested. These findings suggest that underphosphorylated Rb may restrict cell proliferation.     

Recombinant human granulocyte colony-stimulating factor: effects on normal and leukemic myeloid cells

Experiments were conducted to isolate and characterize the gene and gene product of a human hematopoietic colony-stimulating factor with pluripotent biological activities. This factor has the ability to induce differentiation of a murine myelomonocytic leukemia cell line WEHI-3B(D+) and cells from patients with newly diagnosed acute nonlymphocytic leukemia (ANLL). A complementary DNA copy of the gene encoding a pluripotent human granulocyte colony-stimulating factor (hG-CSF) was cloned and expressed in Escherichia coli. The recombinant form of hG-CSF is capable of supporting neutrophil proliferation in a CFU-GM assay. In addition, recombinant hG-CSF can support early erythroid colonies and mixed colony formation. Competitive binding studies done with 125I-labeled hG-CSF and cell samples from two patients with newly diagnosed human leukemias as well as WEHI-3B(D+) cells showed that one of the human leukemias (ANLL, classified as M4) and the WEHI-3B(D+) cells have receptors for hG-CSF. Furthermore, the murine WEHI-3B(D+) cells and human leukemic cells classified as M2, M3, and M4 were induced by recombinant hG-CSF to undergo terminal differentiation to macrophages and granulocytes. The secreted form of the protein produced by the bladder carcinoma cell line 5637 was found to be O-glycosylated and to have a molecular weight of 19,600.     

薯蓣皂苷元对HL-60细胞增殖及细胞周期的影响

采用XTT比色法和流式细胞仪技术观察薯蓣皂苷元(Diosgenin，Dio)对人急性髓性白血病细胞株HL-60的增殖抑制作用以及细胞周期变化。结果表明：XTT法检测其24h的半数抑制浓度(IC50)为7．36mg/L．流式细胞仪检测Dio作用24h后，G0/Gl期细胞增多，S期细胞减少，凋亡细胞增多。Dio可明显抑制HL-60细胞的增殖。     

喙尾琵琶甲提取物的体外抗肿瘤活性研究

[目的]观察喙尾琵琶甲提取物对体外培养人肿瘤细胞株的生长抑制作用。[方法]喙尾琵琶甲粗提物,通过硅胶柱层析分离得不同极性部分,运用MTT法观察不同部分对人白血病细胞株K562和HL-60、人肺癌细胞株A549的生长抑制情况。[结果]粗提物、石油醚和氯仿部分三者最高浓度(300μg/ml)对K562、HL-60、A549的生长抑制率均>69%,半数抑制浓度(IC50)均<100μg/ml。[结论]喙尾琵琶甲粗提物、石油醚和氯仿部分对K562、HL-60、A549的生长具有很好的抑制作用。     

Regulation of cell fate decision of undifferentiated spermatogonia by GDNF

The molecular control of self-renewal and differentiation of stem cells has remained enigmatic. Transgenic loss-of-function and overexpression models now show that the dosage of glial cell line-derived neurotrophic factor (GDNF), produced by Sertoli cells, regulates cell fate decisions of undifferentiated spermatogonial cells that include the stem cells for spermatogenesis. Gene-targeted mice with one GDNF-null allele show depletion of stem cell reserves, whereas mice overexpressing GDNF show accumulation of undifferentiated spermatogonia. They are unable to respond properly to differentiation signals and undergo apoptosis upon retinoic acid treatment. Nonmetastatic testicular tumors are regularly formed in older GDNF-overexpressing mice. Thus, GDNF contributes to paracrine regulation of spermatogonial self-renewal and differentiation.     

苦参素对D-氨基半乳糖苷诱导的肝细胞凋亡的干预研究

[目的]研究氧化苦参碱对肝细胞凋亡的影响。[方法]采用D-氨基半乳糖苷(D-GalN)诱导人源HL-7702肝细胞发生凋亡,探索最佳的凋亡诱导参数,建立肝细胞凋亡模型,并运用建立的体外肝细胞凋亡模型,探讨氧化苦参碱的抗凋亡作用。[结果]D-GalN在60mmol/L浓度下与HL-7702肝细胞孵育8 h为最优建模条件,在此处理条件下经凝胶电泳可见细胞凋亡特征性的DNA ladder;且与对照组相比,HL-7702细胞处理后其ALT、AST、SOD、MDA、Caspases-3水平均显著升高(P0.05)。[结论]D-GalN诱导的HL-7702肝细胞凋亡的发生机制可能与线粒体信号转导途径有关,而氧化苦参碱对D-GalN引起的肝细胞凋亡具有较强的干预作用,其抗凋亡机制可能与抑制Caspases-3、CytC、TNFα和TGF-β1等凋亡因子和诱导抗凋亡因子HO-1表达有关。     

中华补血草黄酮抑制白血病细胞增殖的初探

应用MTT法研究中华补血草不同浓度黄酮提取物对体外培养的人类白血病HL-60细胞株的增殖抑制作用。结果显示：不同浓度的中华补血草黄酮提取液作用人白血病细胞HL-60处理48h后,细胞的生长受到不同程度的抑制,并且随着浓度的升高抑制作用逐渐加强,呈现明显的量效关系,其IC50值为11．55μg／mL。     

鼻咽癌细胞株CNE1转染EB病毒潜伏膜蛋白1(LMP1)后对放射敏感性的影响

目的：研究EB病参LMP1对鼻咽癌高分化细胞株CNE1放射敏感性的影响。方法：用电转染技术将带有EB病毒LMP1基因的真核表达质粒导入鼻咽癌高分化细胞株CNEl，用免疫组化法及Western blot检测LMPl的表达；LMP1对CNEl细胞放射敏感性的影响采用^60钴治疗仪照射后集落形成实验进行观察。结果：CNE1细胞抹转染LMP1基因后LMPl蛋白呈阳性表达，对照放射敏感性比未转染株的细胞存活事低(P＜0．01)。结论：LMPl能增加鼻咽癌细胞的放射敏感性，这种作用可能与LMP1的促细胞转化，抑分化有关。     

大田软海绵酸对HL-7702肝细胞毒性效应的研究

[目的]探讨大田软海绵酸（okadaic acid,OA）对HL-7702肝细胞的毒性效应。[方法]通过细胞计数试剂盒（Cell Counting Kit-8,CCK-8）、细胞形态学观察及流式细胞术等方法,从细胞增殖、细胞凋亡等方面探讨OA对HL-7702肝细胞的毒性效应。[结果]与溶剂对照组相比,OA对HL-7702肝细胞增殖有明显的抑制作用,细胞增殖抑制率随着OA浓度的增加而增加,同时随着染毒时间的延长,细胞增殖抑制率也明显增加;与对照组相比,作用HL-7702肝细胞24h后,5nmol/LOA可明显诱导细胞发生凋亡。[结论]OA可以通过抑制细胞增殖及诱导细胞凋亡的方式对HL-7702肝细胞产生毒性效应,且呈现剂量-效应关系。     

bcl-x基因在两株鼻咽癌细胞中的转录和表达

目的：研究细胞凋亡相关基因bcl-x在人鼻咽癌高分化上皮细胞株CNE-1和低分化上皮细胞株CNE-2Z中的转录和表达。方法：分别抽提两种细胞的总RNA，通过逆转录PCR(RT-PCR)检测bcl-x基因的转录；同时制备两种细胞的蛋白质样品。经免疫印迹检测bcl-x基因的表达。结果：在两株鼻咽癌细胞中均检测到bcl-xL的转录和表达。但没有bcl-xs的表达。结论：bcl-xL在人鼻咽癌高、低分化上皮细胞株中均有表达。但表达量没有明显差异提示其表达可能与细胞分化程度无关。     

毛蚶中天然牛磺酸的提取和活性研究

[目的]提取和纯化毛蚶(Scapharca subcrenata)中的天然牛磺酸,并对其活性进行研究。[方法]采用薄层色谱法(TLC)对提取的牛磺酸纯度进行分析,并对其结构用红外光谱(IR)和核磁共振波谱(NMR)进行鉴定,然后对其细胞毒活性进行检测。[结果]毛蚶富含牛磺酸,对人白血病细胞HL-60、肝癌细胞SMMC-7721、肺癌细胞A-549、乳腺癌细胞MCF-7和结肠癌细胞SW480没有明显的细胞毒活性。[结论]该研究为天然牛磺酸的开发和利用提供了依据。     

脂代谢通路对鸡雄性生殖细胞分化的调控机制

【目的】探索家鸡雄性生殖细胞分化过程中脂代谢相关基因以及信号通路的调控机制,以期为完善体外诱导体系提供依据。【方法】采用流式细胞分选法获得纯度较高的胚胎干细胞(embryonic stem cell,ESC)、原始生殖细胞(primitive germ cells,PGC)和精原干细胞 (spermatogonial stem cell,SSC),提取细胞总RNA。利用RNA-seq高通量分析方法对这三种细胞进行转录组水平测序,进行GO（Gene ontology）分析和KEGG通路富集,寻找脂代谢相关基因以及信号通路;并利用脂代谢--视黄醇代谢通路终产物视黄酸（retinoic acid,RA）以及抑制剂苯磺酰异羟肟酸 (piloty’s acid)在体外诱导ESC向雄性生殖细胞分化和体外鸡胚注射后孵化,qRT-PCR（quantitative real time PCR）检测视黄醇代谢通路上差异基因的表达变化,与RNA-seq结果进行比较分析同时检测雄性生殖细胞标记基因的变化情况。【结果】GO功能显著性富集和 Pathway 显著性富集分析结果发现：在ESC向SSC分化过程中共存在328个基因持续参与脂代谢调控,富集到27条脂代谢通路中,包括视黄醇代谢、初级胆汁酸的合成、甾类激素的生物合成、脂肪酸代谢、甘油酯代谢以及类固醇的生物合成等通路。在视黄醇代谢通路中ADH5在PGC中特异表达,ALDH1A1在整个发育过程中持续上调,ADH5和ALDH1A1在细胞中参与视黄酸的合成;CYP26b1在整个发育过程中持续上调,参与视黄酸的降解过程;RA体外诱导ESC向SSC方向诱导试验结果表明ADH5、ALDH1A1和CYP26b1家族基因在体外RA诱导过程中变化与体内分化过程一致,RA诱导组产生的SSC样细胞显著高于控制组和Piloty’s Acid+RA组。鸡胚注射抑制剂试验结果表明视黄醇通路被抑制后孵化至18d后SSC细胞表面特异标记基因integrinα6和integrinβ1的表达水平显著的低于正常的孵化组(CON)和阴性对照组（BLANK）【结论】脂代谢--视黄醇代谢通路在家鸡雄性生殖细胞的分化过程中起重要作用,体外利用视黄醇代谢通路终产物RA进行诱导时第2天出现类胚体,第4、6天类胚体逐渐增大,第8天开始裂解,在第10天出现SSC样细胞,而在诱导过程中抑制视黄醇通路信号后则会降低SSC样细胞的产生,而在体外孵化过程中视黄醇通路抑制后也能影响SSC细胞的产生。     

Control of the reversibility of cellular quiescence by the transcriptional repressor HES1

The mechanisms by which quiescent cells, including adult stem cells, preserve their ability to resume proliferation after weeks or even years of cell cycle arrest are not known. We report that reversibility is not a passive property of nondividing cells, because enforced cell cycle arrest for a period as brief as 4 days initiates spontaneous, premature, and irreversible senescence. Increased expression of the gene encoding the basic helix-loop-helix protein HES1 was required for quiescence to be reversible, because HES1 prevented both premature senescence and inappropriate differentiation in quiescent fibroblasts. In some human tumors, the HES1 pathway was activated, which allowed these cells to evade differentiation and irreversible cell cycle arrest. We conclude that HES1 safeguards against irreversible cell cycle exit both during normal cellular quiescence and pathologically in the setting of tumorigenesis.