Forced expression of theOct-4 gene influences differentiation of embryonic stem cells

By transfecting an Oct-4 expression plasmid into embryonic stem cells (ES cells), the ES-O cell line was constructed, which sustained the expression of Oct-4 gene when induced by retinoic acid. Forced expression of Oct-4 gene could not sustain the stem property of ES-O cells without the differentiation inhibiting factor LIF, but if LIF exists, forced expression of Oct-4 gene could enhance the ability to sustain the undifferentiation state and inhibit cell differentiation induced by retinoic acid. It was indicated that Oct-4 must cooperate with LIF to sustain the undifferentiation state of ES cells. During the cell differentiation, ES-O cells tend to differentiate into neural cells, suggesting that forced expression of Oct-4 gene may be in relation with the differentiation of neuroderm.     

肿瘤抑制基因p53的研究进展

综述了p53基因的特性、认识阶段、作用机理主其在癌症研究中的进展。     

Anti-CD44 mAb remodels biological behaviors of spheroid cells with stemness from human ovarian cancer cell line SKOV-3

There is accumulating evidence that cancer stem cells (CSCs) play an important role in tumor progression. Novel strategies targeting CSCs have been widely researched. In the present study, we explored whether such CSCs existed in human ovarian cancer (OVCA) cell line and whether anti-CD44 antibody had effects on such subpopulation. We isolated and identified spheroid cells from SKOV-3. Then we used A3D8, an anti-CD44 mAb to treat spheroid cells with so-called "stemness". Effects of A3D8 on spheroid cells’ biological behaviors were examined. Our findings showed that there was a small subpopulation that had so-called "stemness" in SKOV-3 cell line. Against spheroid cells, A3D8 can (1) inhibit cell proliferation; (2) change cell cycle distribution and expression of p21, CDK2 and cyclinA; (3) enhance cisplatin (DDP)-induced apoptosis; (4) promote cell differentiation; (5) inhibit clone formation efficiency; (6) reduce invasive efficacy; (7) inhibit tumorigenicity. Thus, to sum up points which we have just showed, spheroid cells isolated from SKOV-3 can be used as an appropriate in vitro model for relevant study of human ovarian CSCs. And our results reasoned that anti-CD44 therapy may become a potential promising strategy for OVCA treatment.     

视黄酸对胃癌细胞恶性表型的影响

研究ｔ－ＲＡ对胃癌细胞的作用和探讨其作用机理．结果表明：１）ｔ－ＲＡ能够有效地抑制胃癌细胞的生长．２）ｔ－ＲＡ能够降低胃癌细胞在软琼脂中形成集落的能力．３）ｔ－ＲＡ能够降低胃癌细胞的粘附能力．４）ｔ－ＲＡ能够抑制胃癌细胞在裸鼠中形成肿瘤的能力．４）扫描电镜观察显示,经ｔ－ＲＡ处理后,胃癌细胞表面的微绒毛消失．以上结果表明,ｔ－ＲＡ对胃癌细胞的恶性表型有显著的抑制作用．ｔ－ＲＡ可能作为治疗胃癌的有效药物．     

视黄素受体介导的视黄素（retinoids）抗癌作用

对近年来视黄素受体介导视黄素抗癌作用机理的研究进展作一综述,主要有：1）视黄素受体;2）视黄素受体与细胞生长;3）视黄素受体与孤生受体的的相关性;4）视黄素受体对AP-1活性的抑制作用;5）视黄素受体介导的信号转导途径。通过研究,对于探讨视黄素受体的功能、阐明视黄素的抗癌机理、合成更多的受体选择性视黄素具有重要的现实意义。     

Chromosomal localization of a novel retinoic acid induced geneRA28 and protein distribution of its encoded protein

GeneRA28 is a retinoic acid induced novel gene isolated in our laboratory previously. All-trans retinoic acid (ATRA) was used to induce lung adenocarcinoma cell line GLC-82, andRA28 was obtained by subtractive hybridization. Green fluorescent protein (GFP) has emerged as a unique tool for examining introcellular phenomena in living cells. GFP possesses an intrinsic fluorescence at 488 nm that does not require other co-factors. In this report, an eukaryotic expression plasmid pEGFP-C1-RA28 was constructed and transfected with parental cell line GLC-82 to analyze protein expression and its distribution in living cells. Moreover, radiation hybrid (RH) technique was used to localizeRA28 to the chromosome. The results show that geneRA28 is mapped to the chromosome 19q13.1 region, its encoded protein is distributed on cell membrane. All the results further demonstrate that GFP and RH techniques are accurate, fast, repetitive, and will be powerful methods for investigating the gene and protein localization.     

人类磷酸泛酰巯基乙胺结合蛋白新基因的分离和鉴定

在对AD293和HEK293进行差减杂交以探索两者在吸附和凋亡特性上的差异时,从AD293的高表达文库中分离得到一段新的cDNA片段.从人类胎脑文库克隆得到该基因,全长2 745 bp,编码的蛋白含518个氨基酸,被预测为磷酸泛酰巯基乙胺结合蛋白.该基因在染色体上定位于2p22.3,包含8个外显子.该cDNA编码的蛋白序列含有一个凋亡抑制蛋白5结构域,外皮蛋白重复片段和铜结合辛肽重复片段.RT-PCR分析显示该基因在人类正常组织和癌组织中广泛表达,但在癌组织中表达量相对较低,提示其可能对细胞凋亡有抑制作用.该基因在进化过程中高度保守.     

Sequential activation of HOX2 homeobox genes by retinoic acid in human embryonal carcinoma cells

RETINOIC acid had been implicated as a natural morphogen in chicken and frog embryogenesis, and is presumed to act through the gene regulatory activity of a family of nuclear receptors. Homeobox genes, which specify positional information in Drosophila and possibly in vertebrate embryogenesis, are among the candidate responsive genes. We previously reported that retinoic acid specifically induces human homeobox gene (HOX) expression in the embryonal carcinoma cell line NT2/D1. We now show that the nine genes of the HOX2 cluster are differentially activated in NT2/D1 cells exposed to retinoic acid concentrations ranging from 10(-8) to 10(-5) M. Genes located in the 3' half of the cluster are induced at peak levels by 10(-8) M retinoic acid, whereas a concentration of 10(-6) to 10(-5) M is required to fully activate 5' genes. At both high and low retinoic acid concentrations, HOX2 genes are sequentially activated in embryonal carcinoma cells in the 3' to 5' direction.     

IL-24联合大蒜素体外抗肺癌细胞生长的实验研究

目的探讨抑癌基因IL-24联合大蒜素对肺癌A549细胞凋亡的影响,并初步探讨其作用机制.方法提取前期构建的p DC316-h IL-24-EGFP质粒,转染肺癌A549细胞,分为A组(空白对照组)、B组(单独大蒜素组(40μL/m L))、C组(脂质体+IL-24组)、D组(大蒜素(40μL/m L)+脂质体+IL-24).荧光显微镜下观察质粒的转染情况;流式细胞仪检测细胞凋亡;Western blot法检测p DC316-h IL-24-EGFP、大蒜素和联合用药作用A5 4 9细胞4 8 h后IL-24,Bax,Bcl-2和Caspase-3蛋白表达水平.结果大蒜素(40μL/m L)和p DC316-h IL-24-EGFP单用48 h对A549细胞均有明显抑制作用;大蒜素(40μL/m L)联合p DC3 1 6-h IL-24-EGFP比单用p DC3 1 6-h IL-24-EGFP作用更强(P0.05);大蒜素(40μL/m L)、p DC316-h IL-24-EGFP和两药联用48 h后,A549细胞凋亡率分别为32.7%,39.4%和68.8%;大蒜素(40μL/m L)和/或IL-24作用于A549细胞48 h后,Bax/Bcl-2的比值及Caspase-3表达均上调,联合用药组效果尤其明显.结论p DC316-h IL-24-EGFP联合大蒜素可协同抑制人肺癌A549细胞生长,机制可能是通过调节基因Bax/Bcl-2的表达比率,并上调Caspase-3的表达,进而诱导A549细胞的凋亡.     

白细胞介素24在抗肿瘤方面的应用

人类黑色素瘤分化相关基因-7/白介素-24(MDA-7/IL-24)是近年发现的具有细胞因子特性的抗肿瘤作用的基因,它能够通过膜受体或非受体介导的凋亡途径对多种肿瘤细胞产生杀伤作用,而对正常细胞没有影响.此外,IL-24还具有抑制肿瘤新生血管形成、增强放疗敏感性和免疫调节作用.作为一种具有多种抗肿瘤功能的细胞因子IL-...     

XIAP在TRAIL抗性细胞HCT116 bax-/-中的作用机制研究

为了探索结直肠癌细胞HCT116抗TRAIL诱导凋亡的分子机制,本课题以其抗性细胞HCT116 bax~(-/-)为实验对象进行了研究.通过利用目前最热的基因定点编辑技术Clustered regularly interspaced short palindromic repeats(CRISPR)/CRISPR-associated(Cas)9系统将HCT116bax~(-/-)的XIAP(X-linked inhibitor of apoptosis protein)基因彻底敲除后,用TRAIL处理,发现其恢复了对TRAIL的敏感,形态学发生了明显凋亡,而且western blot检测显示PARP蛋白发生了完全剪切.由此证明敲除XIAP基因能克服HCT116 bax~(-/-)对TRAIL的抗性.这些发现对肿瘤细胞抗TRAIL的分子机理研究以及肿瘤的个性化治疗有非常重要的意义.     

Recombinant sTRAIL induces cell death of tumor cell lines as well as primary cancer cells

Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) is a new member of TNF family. It was reported that TRAIL could induce apoptosis of tumor cells but not normal cells in tissue culture system. To further study the biological activity and potential clinical significance, a recombinant soluble TRAIL (rsTRAIL) has been expressed stably in E. coli after transformation of pET28b vector containing the extracellular domain of TRAIL. The yield of rsTRAIL is approximately as high as 60% of whole bacterial proteins. The rsTRAIL, purified by Ni+ -agarose affinity chromatography, could remarkably trigger apoptosis at the concentrations of 0.1-1 μg/mL in all 7 tumor cell lines tested in vitro. However, this killing activity has not been observed in mouse fibroblast cell line (NIH3T3) as normal control. Further investigation shows that the rsTRAIL could also kill primary tumor cells isolated freshly from patients with cardiac cancer, breast cancer and malignant thymoma, while the normal human peripheral blood lymphocytes are not killed under the same conditions. These results provide new evidence that rsTRAIL could induce apoptosis of tumor cells specifically and it could be a new promising medicine for tumor therapy.     

Cloning and identification of a novel human glioma differentiation related geneGDR1

In order to identify the genes associated with glioblastoma differentiation, some ESTs, expressed differentially in the control cell and the differentiated human glioblastoma cell line BT-325 induced by the all-trans retinoid acid, have been isolated by the method of DDRT-PCR. Of the 46 ESTs sequenced, 19 are from new genes. A full-length 1 535-bp cDNA, termed geneGDR1, has been isolated from the human cDNA library using the probe designed according to one of the novel ESTs, HGBB098. The open reading frame ofGDR1 gene encodes a putative protein containing 334 amino acid residues. Blast against the current GenBank DNA and protein sequence database did not reveal significant homology with any known proteins. RT-PCR shows thatGDR1 mRNA level increased in the differentiated BT-325 cells after being treated with RA. The different expression patterns ofGDR1 mRNA in human tissues have been detected through the multiple tissue Northern blot hybridization.     

青龙衣的化学成分和抗肿瘤活性研究

研究青龙衣的化学成分及抗肿瘤活性.利用硅胶柱色谱和开放ODS柱色谱等分离技术从青龙衣的95%乙醇提取物中分离得到了11个化合物,通过理化性质、波谱数据分析等方法,鉴定了全部化合物结构.采用MTT法,选取人胃癌细胞株(SGC7901),人肝癌细胞株(Hep G2),人肺腺癌细胞株(A549),乳腺癌细胞株(MCF7),结肠癌细胞株(Lo Vo)对化合物体外抗肿瘤作用进行筛选.从青龙衣中分离鉴定了11个化合物,分别为正二十九烷醇(nonacosanol)(1),[1-(4'-甲氧基苯基)-7-(3'-甲氧基,2'-羟基苯基)-3',4'-环氧-3-庚酮[3',4'-epoxy-1-(4'-methoxylphenyl)-7-(3'-methoxyl-2'-hydroxyphenyl)-heptane-3-one](2),正三十一烷醇(hentriacontanal)(3),1-(4'-羟基苯基)-7-(3'-甲氧基-4'-羟基苯基)-庚烷-3-醇[1-(4'-hydorxyphenyl)-7-(3'-methoxy-4'-hydorxyphenyl)-hepta-3-ol](4),4,6-二羟基-3,4-二氢-1-萘酮(4,6-dihydroxy-3,4-dihydro-naphthalenone)(5),胡桃醌(5-hydroxy-1,4-naphthoquinone)(6),β-谷甾醇(beta-sitosterol)(7),齐墩果酸(oleanolic acid)(8),香草酸(vanillic acid)(9),槲皮素(quercetin)(10),香草醛(vanillin)(11).化合物5、10对肿瘤细胞均有很强的生长抑制作用,IC50≤35μmol/L.化合物8对肿瘤细胞有较强的生长抑制作用,IC50≤58μmol/L.化合物2、3、6和7对个别肿瘤细胞有作用,其他化合物对肿瘤细胞没有生长抑制作用.11个化合物均为已知化合物,其中化合物1,3,10,11为属内首分,化合物5、8和10均具有较显著的抗肿瘤活性.