Hesperidin as a preventive resistance agent in MCF-7 breast cancer cells line resistance to doxorubicin

Objective:To evaluate of hesperidin to overcome resistance of doxorubicin in MCF-7 resistant doxorubicin cells(MCF-7/Dox)in cytotoxicity apoptosis and P-glycoprotein(Pgp)expression in combination with doxorubicin.Methods:The cytotoxic properties.50%inhibition concentration(IC_(50))and its combination with doxorubicin in MCF-7 cell lines resistant to doxorubicin(MCF-7/Dox)cells were determined using MTT assay.Apoptosis induction was examined by double staining assay using ethidium bromide-acridine orange.Immunocytochemistry assay was performed to determine the level and localization of Pgp.Results:Single treatment of hesperidin showed cytotoxic activity on MCF-7/Dox cells with IC_(50)value of 11μmol/L.Thus,combination treatment from hesperidin and doxorubicin showed addictive and antagonist effect(CI>1.0).Hesperidin did not increase the apoptotic induction,but decreased the Pgp expressions level when combined with doxorubicin in low concentration.Conclusions:Hesperidin has cytotoxic effect on MCF-7/Dox cells with IC_(50)of 11μmol/L.Hesperidin did not increased the apoptotic induction combined with doxorubicin.Cochemotherapy application of doxorubicin and hesperidin on MCF-7/Dox cells showed synergism effect through inhibition of Pgp expression.

Investigation of Oxidation-Reduction Properties of Growing Mediums for Cell Culture of Mammals under the Effect of Cosmo-Geophysical Factors

In model experiments were studied the effect of cosmo-geophysical factors of environment (hypomagnetic conditions during 2 days ≈ 1 mkT;electromagnetic irradiation (10 min - 2 MHz with amplitude 5 V/m and power 30 mkVt, background 2 - 4 mkVt), γ-quantum (10 min—from the source 137Cs) and its combined effect on the physic-chemical properties (ORP and pH) of growing medium for cell culture of mammals as nutrition medium 199 (PanEco, Russia). It was used a clear solution of medium (solution 1) and with the adding of 10% embryo bull serum—model of bio-medium (solution 2). Hypomagnetic conditions evoked the decreasing of ORP and pH value in both solutions, electromagnetic irradiation in the solution 1 which evoked the decreasing of ORP and the increasing of pH value, and in the solution 2, on the contrary, the increasing of ORP with the unchanging pH value. γ-radiation sharply decreased ORP value and didn’t change pH in solution 1, i.e. the reduction properties increased. There is insignificant increasing of ORP value and the decreasing of pH is noted in the solution 2, that it is characterized with the increasing of oxidative properties of solution. Under the combined effect of hypomagnetic conditions and electromagnetic irradiation, the values of investigating parameters in the solution 1 decreased and in the solution 2 increased. It was observed acute decreasing of ORP value in both solutions under the combined effect of hypomagnetic conditions and γ-radiation, i.e. the reductive properties of the solutions increased sharply. In this the concentration H+ significantly decreased, (p γ-radiation led to the decreasing of ORP and pH values in both solutions. Thus, the studying factors significantly change the oxidation-reduction properties of growing mediums. The investigation of the processes in biological mediums plays the important role in the assessment of environment effect during the flight in inter-planet space.

Synergistic anticancer properties of docosahexaenoic acid and 5-fluorouracil through interference with energy metabolism and cell cycle arrest in human gastric cancer cell line AGS cells

AIM: To explore the synergistic effect of docosahexaenoic acid(DHA)/5-fluorouracil(5-FU) on the human gastric cancer cell line AGS and examine the underlying mechanism.METHODS: AGS cells were cultured and treated with a series of concentrations of DHA and 5-FU alone or in combination for 24 and 48 h. To investigate the synergistic effect of DHA and 5-FU on AGS cells, the inhibition of cell proliferation was determined by MTT assay and cell morphology. Flow cytometric analysis was also used to assess cell cycle distribution, and the expression of mitochondrial electron transfer chain complexes(METCs)?Ⅰ, Ⅱ and Ⅴ in AGS cells was further determined by Western blot analysis. RESULTS: DHA and 5-FU alone or in combination could markedly suppress the proliferation of AGS cells in a significant time and dose-dependent manner. DHA markedly strengthened the antiproliferative effect of 5-FU, decreasing the IC50 by 3.56-2.15-fold in an apparent synergy. The morphological changes of the cells were characterized by shrinkage, cell membrane blebbing and decreased adherence. Cell cycle analysis showed a shift of cells into the G0/G1 phase from the S phase following treatment with DHA or 5-FU(G0/G1 phase: 30.04% ± 1.54% vs 49.05% ± 6.41% and 63.39% ± 6.83%, respectively, P < 0.05; S phase: 56.76% ± 3.14% vs 34.75% ± 2.35% and 25.63% ± 2.21%, respectively, P < 0.05). Combination treatment of DHA and 5-FU resulted in a significantly larger shift toward the G0/G1 phase and subsequent reduction in S phase(G0/G1 phase: 69.06% ± 2.63% vs 49.05% ± 6.41% and 63.39% ± 6.83%, respectively, P < 0.05; S phase: 19.80% ± 4.30% vs 34.75% ± 2.35% and 25.63% ± 2.21%, respectively, P < 0.05). This synergy was also reflected in the significant downregulation of the expression of METCs in AGS cells.CONCLUSION: Synergistic anticancer properties of DHA and 5-FU may involve interference with energy production of AGS cells via downregulation of METCs and cell cycle arrest.

In vitro acute cytotoxicity of the neonicotinoid insecticide acetamiprid to FG cells, the gill cell line of flounder Paralichthy olivaceus

The in vitro acute cytotoxicity of the neonicotinoid insecticide acetamiprid to FG cell line, derived from the gill of flounder Paralichthys olizaceus, was tested by the three widely used endpoint bioassays-neutral red （NR） assay, tetrazolium （MTT） assay and cell protein assay. It was found that acetamiprid was increasingly toxic to FG cells at concentrations of 1 μg/cm^3 or above, and the inhibitory concentration 50% values for NR, MTF, and cell protein assays were 38.38, 36.27 and 32.03 μg/cm^3, respectively. This appeared to be the first report on the in vitro cytotoxicity of acetamiprid to non-mammalian vertebrate cells. Ultrastructural examination revealed that for the cells exposed to 60 μg/cm^3 acetamiprid for 48 h, their mitochondria were severely damaged with the cristae swelled up or disrupted, while their nuclei and rough endoplasmic reticlum （RER） appeared to be still normal. This suggests that mitochondria are possibly the primary target of acetamiprid.

REARRANGEMENT AND EXPRESSION OF T CELL RECEPTOR β GENE IN HUMAN HEMOPOIETIC CELL LINES AND PRIMARY CELLS FROM ACUTE LYMPHOCYTIC LEUKEMIAS

Using Southern blot, Northern blot and Quick blot methods, we examined the rearrangement and expression of TCR βgene in four early differentiation stage cell lines from human hemopoietic system, namely HL-60, Jurkat, Daudi and Raji cells as well as lymphocytes from 17 acute lymphocytic leukemia （ALL） patients. The results showed. Ⅰ) Rearrangement of TCR βgene was seen in Jurkat cells. A germline pattern was observed in HL-60, Daudi and Raji cells. 2) Eight of 9 patients with T-ALL had cells with rearranged TCR βgene. But two of 3 patients with B-ALL and three of 5 patients with nonT, nonB-ALL also had cells with rearranged TCR βgene. 3) A 1.3 kb full-length transcript and a 1.0 kb truncated transcript were detected in Jurkat cells by probing with 32P-TCR βcDNA. But some leukemic B cells also expressed an incompleted transcript. 4) TCR βmRNA was detected in six of 8 patients with T-ALL, four of 5 patients with nonT, nonB-ALL and one of 3 patients with B-ALL. But the level of expression was quite differ ent. The dual-rearrangement and the abnormal expression may give us a new clue for researching leukemogenesis.

Establishment and expression of recombinant human glial cell linederived neurotrophic factor and TNF α receptor in human neural stem cells

Objective:To investigate the interference and expression of human glial cell line-derived neurotrophic factor(hCDNF) and soluble TNF alpha(sTMFRⅠ) receptor genes in neural stem cells and to evaluate the roles of these proteins in the genetic treatment of spinal cord injury.Methods:Full-length of GDNF cDNA(538 bp) and sTMFRⅠcDNA(504 bp) were inserted into the early 1 region of adenovirus genomic DNA respectively and were immediated by the human cytomegalovirus(gene promoter/enhancer). These adenoviruses were propagated in HEK293 cells via homologous recombination for 7-10 days in vivo,then they were used to infect human neural stem ceils.The infection and expression of gene were tested under immunofluorescence.ELISA and Westem-blot after 48 hours.Results:Almost all the cultured cells showed the nestin immunofluorescence positive staining,which was the characteristics of neural stem cell.A great quantity of EGFP and KFP were observed in neural stem cells,which indicated the expression of GDNF and sTMFRⅠ.After transfection of GDNF and sTMFRⅠgenes,many neural stem cells show GFAP and tubulin immunofluorescence positive staining,which meant that most neural stem cells differentiated into neuron at that condition.Conclusions:The infective efficiency of adenovirus is greatly acceptable to neural stem cell,thus adenovirus provide a useful vector for exogenous GDNF and sTMFRⅠgenes expressing in neural stem cells,which is useful for differentiation of neural stem cell.

Establishment and characterization of a canine chondrosarcoma cell line:Mango

In the global progress of bone tumor research,established stable and long-lasting transgenic chondrosarcoma(CSA)cell lines are rare,mainly of murine and human origin,while the establishment of canine CSA cell lines has yet to be reported.This study established a canine CSA cell line to facilitate the basic clinical study of canine CSA.Fifty fve cases of canine osteolytic disease were collected,and more than 10 bone tumor samples from dogs with typical clinical signs were used for primary cell culture.A cell line with stable passaging for more than 100 generations and mouse tumorigenic ability was successfully cultured.According to the clinical characteristics of the dog and the histopathological results of the primary tumor,CSA was diagnosed,and the CSA cell line was designated Mango.Immunohistochemical(IHC)results showed that the immunoreactivity of bone gamma-carboxyglutamate protein(BGLAP),secreted protein acidic and rich in cysteine(SPARC),alkaline phosphatase(ALPL),vimentin(VIM)and S100 were positive.However,the immunoreactivity of pan-cytokeratin(PCK),chromogranin A(CGA),and platelet endothelial cell adhesion molecule-1(CD31)was negative.Immunofuorescence(IF)results showed that the protein expressions in the Mango cell line were consistent with the IHC identifcation of the primary tumor.The Mango cell line’s doubling time was 43.92 h,and the cell formation rate exceeded 20%.There were abnormal chromosome numbers,hetero staining with toluidine blue,and certain calcifcation abilities.It could be passaged stably and continuously without changing the cell morphology and characteristics.In vivo,the cells were successfully injected into the nude mice model with a tumorigenic rate of 100%.The immunophenotype of the xenograft tumor was consistent with that of the primary tumor.Therefore,we efectively established a canine CSA cell line.As a promising cell material,this cell line can be used to construct a tumor-bearing model conducive to the subsequent basic research of canine CSA.Moreover,because of its similarity to human CSA,the animal model of CSA is also indispensable for investigating human CSA.

Characterization of the infectivity of an Indonesian Zika virus strain in mammalian cell lines

Objective:To characterize the infection patterns and growth characteristics of the Zika virus(ZIKV)strain JMB-185 from Indonesia in various mammalian cell lines.Methods:ZIKV was grown in human(A549,HEK293,HepG2,Huh7,Jurkat,and THP-1)and non-human mammalian(RAW264.7,Vero,and Vero76)cell lines.Viral replication kinetics were measured using plaque assay,while intra-and extracellular viral RNA concentrations were assessed using RT-PCR.Flow cytometry was used to quantify the infected cells and cell viability was measured using an MTT assay.The ability of ZIKV to infect cell lines was visualized using a fluorescence immunostaining assay.Results:This ZIKV strain preferentially infected the lung,kidney,and liver cell lines A549,HEK293,Huh7,Vero,and Vero76,but not the immune cells Jurkat,RAW264.7,and THP-1.By contrast,the ZIKV showed no sign of infection in HepG2 cells,while maintaining viral titer over 3 days post-infection,with no infection recorded in immunostaining,no increase in viral RNA,and no indication of cell deterioration.Conclusions:The Indonesian ZIKV strain has a similar infection profile as other strains,except for its poor infectivity on HepG2 cells.Information on the growth characteristics of Indonesia ZIKV will help expand our understanding of the biology of ZIKV which will be useful for various applications including antiviral discovery.

GATA binding protein 2 mediated ankyrin repeat domain containing 26 high expression in myeloid-derived cell lines

BACKGROUND Thrombocytopenia 2,an autosomal dominant inherited disease characterized by moderate thrombocytopenia,predisposition to myeloid malignancies and normal platelet size and function,can be caused by 5’-untranslated region(UTR)point mutations in ankyrin repeat domain containing 26(ANKRD26).Runt related transcription factor 1(RUNX1)and friend leukemia integration 1(FLI1)have been identified as negative regulators of ANKRD26.However,the positive regulators of ANKRD26 are still unknown.AIM To prove the positive regulatory effect of GATA binding protein 2(GATA2)on ANKRD26 transcription.METHODS Human induced pluripotent stem cells derived from bone marrow(hiPSC-BM)INTRODUCTION Ankyrin repeat domain containing protein 26(ANKRD26)acts as a regulator of adipogenesis and is involved in the regulation of feeding behavior[1-3].The ANKRD26 gene is located on chromosome 10 and shares regions of homology with the primate-specific gene family POTE.According to the Human Protein Atlas database,the ANKRD26 protein is localized to the Golgi apparatus and vesicles,and its expression can be detected in nearly all human tissues[4].Moreover,UniProt annotation revealed that ANKRD26 is localized in the centrosome and contains coiled-coil domains formed by spectrin helices and ankyrin repeats[5,6].The most common disease related to ANKRD26 is thrombocytopenia 2(THC2),which is a rare autosomal dominant inherited disease characterized by lifelong mild-to-moderate thrombocytopenia and mild bleeding[7-9].Caused by the variants in the 5’-untranslated region(UTR)of ANKRD26,THC2 is defined by a decrease in the number of platelets in circulating blood and results in increased bleeding and decreased clotting ability[8,10].Due to the point mutations that occur in the 5’-UTR of ANKRD26,its negative transcription factors(TFs),Runt related transcription factor 1(RUNX1)and friend leukemia integration 1(FLI1),lose their repression effect[11].The persistent expression of ANKRD26 increases the activity of the mitogen activated protein kinase and extracellular signal regulated kinase 1/2 signaling pathways,which are potentially involved in the regulation of thrombopoietin-dependent signaling and further impair proplatelet formation by megakaryocytes(MKs)[11].However,the positive regulators of ANKRD26,which might be associated with THC2 pathology,are still unknown.

New 4-imino-4H-Chromeno[2,3-d]Pyrimidin-3(5H)-Amine: Synthesis, Cytotoxic Effects on Tumoral Cell Lines and in Silico ADMET Properties

The synthesis of new 4-imino-4H-chromeno[2,3-d]pyrimidin-3(5H)-amine in four steps including one step under microwave dielectric heating is reported. The structural identity of the synthesized compounds was established according to their spectroscopic analysis, such as FT-IR, NMR and mass spectroscopy. These new compounds were tested for their antiproliferative activities on seven representative human tumoral cell lines (Huh7 D12, Caco2, MDA-MB231, MDA-MB468, HCT116, PC3 and MCF7) and also on fibroblasts. Among them, only the compounds 6c showed micromolar cytotoxic activity on tumor cell lines (1.8 50 50 > 25 μM). Finally, in silico ADMET studies ware performed to investigate the possibility of using of the identified compound 6c as potential anti-tumor compound.

Vascular Channel Formation by Osteosarcoma Cells in Vitro: Vasculogenic Mimicry

Objective: To observe whether there is evidence for vascular channel formation by osteosarcoma cellsin vitro and to illustrate mechanism of vasculogenic mimicry in osteosarcoma.Methods: Osteosarcoma cell lines (U-2OS) were tested for their ability to form tubular networks in three-dimensional culture containing type I collagen. The structures of the tubular networks were observed under a phase contrast microscope and an electron microscope.Results: Observation under light microscopy and electron microscopy showed that high aggressive osteosarcoma cells line (U-2OS) formed networks containing channels when grown in three-dimensional culture containing type I collagen in the absence of endothelial cells or fibroblasts.Conclusion: These observations strongly suggest that aggressive osteosarcoma cells may generate vascular channels that facilitate tumor perfusion independent of tumor angiogenesis and have the ability of vasculogenic mimicry. Key words osteosarcoma cells line - vasculogenesis mimicry - angiogenesis - 3-dimensional cultures This study was supported in part by the National Natural Sciences Foundation of China (No. 30271314).

Endogenous neurogenesis in adult mammals after spinal cord injury

During the whole life cycle of mammals, new neurons are constantly regenerated in the subgranular zone of the dentate gyms and in the subventricular zone of the lateral ventricles. Thanks to emerging methodologies, great progress has been made in the characterization of spinal cord endogenous neural stem cells （ependymal cells） and identification of their role in adult spinal cord development. As recently evidenced, both the intrinsic and extrinsic molecular mechanisms of ependymal cells control the sequential steps of the adult spinal cord neurogenesis. This review introduces the concept of adult endogenous neurogenesis, the reaction of ependymal cells after adult spinal cord injury （SCI）, the heterogeneity and markers of ependymal cells, the factors that regulate ependymal cells, and the niches that impact the activation or differentiation of ependymal ceils.

Screening of the Metastasis-Associated Genes by Gene Chip in High Metastatic Human Ovarian Cancer Cell Lines

Affymetrix U133A oligonucleotide microarrays were used to study the differences of gene expressions between high （H） metastatic ovarian cancer cell line, HO-8910PM, and normal ovarian tissues （C）. Bioinformatics was used to identify their chromosomal localizations. A total of 1,237 genes were found to have a difference in expression levels more than eight times. Among them 597 were upregulated [Signal Log Ratio （SLR） ≥3], and 640 genes were downregulated （SLR≤-3）. Except one gene, whose location was unknown, all these genes were randomly distributed on all the chromosomes. However, chromosome 1 contained the most differentially expressed genes （115 genes, 9.3%）, followed by chromosome 2 （94 genes, 7.6%）, chromosome 12 （88 genes, 7.1%）, chromosome 11 （76 genes, 6.1%）, chromosomes X （71 genes, 5.7%）, and chromosomes l7 （69 genes, 5.6%）. These genes were localized on short-arm of chromosome （q）, which had 805 （65.1%） genes, and the short arms of No.13, 14, 15, 21, and 22 chromosomes were the only parts of the chromosomes where the differentially expressed genes were localized. Functional classification showed that most of the genes （306 genes, 24.7%） belonged to the enzymes and their regulator groups. The subsequent group was the nucleic acid binding genes （144 genes, 11.6%）. The rest of the top two groups were signal transduction genes （137 genes, 11.1%） and proteins binding genes （116 genes, 9.4%）. These comprised 56.8% of all the differentially expressed genes. There were also 207 genes whose functions were unknown （16.7 %）. Therefore it was concluded that differentially expressed genes in high metastatic ovarian cancer cell were supposed to be randomly distributed across the genome, but the majority were found on chromosomes 1, 2, 12, 11, 17, and X. Abnormality in four groups of genes, including in enzyme and its regulator, nucleic acid binding, signal transduction and protein binding associated genes, might play important roles in ovarian cancer metastasis. Those genes need to be further studied.

LINE-1 ORF-1p过表达对肝癌细胞株SMMC7721增殖和锚定非依赖性生长的影响

目的研究逆转座子L1编码蛋白ORF-1p的表达对肝癌细胞株SMMC7721细胞增殖的影响。方法利用带Flag标签的L1 ORF1表达载体,转染SMMC7721细胞;采用Western blot法检测反转座子L1 ORF1编码蛋白ORF-1p的表达;采用软琼脂成集落实验和相关报告基因检测ORF-1p表达对肝癌细胞p53、p15和p21活性的影响。结果在SMMC7721细胞中,Flag-ORF-1p表达能够显著促进该细胞的增殖(P<0.05),增强该细胞的锚定非依赖性生长(P<0.05),降低p53、p15和p21报告基因的活性。结论 L1基因编码蛋白ORF-1p能够促进肝癌细胞的生长、浸润以及肿瘤的形成。

建立doxycycline诱导表达Xaf1的肿瘤细胞株

【目的】为探索XIAP相关因子1(Xaf1)调节肿瘤细胞凋亡的机制,利用基因开关调节系统(Tet-on),拟建立由doxycycline调控表达的Xaf1诱导细胞株。【方法】将pTREHA-Xaf1和pWZL-Hyg质粒用基因转染技术转入稳定表达rtTA的Saos-2细胞中。经过hygromycin的抗性筛选,挑出并扩增表达Xaf1的细胞株。在8例实验组中加入doxycycline,和不加doxycycline的8例对照组比较,重复3次实验用免疫印迹法和免疫荧光显微镜检测doxycycline对Xaf1表达的调控。Xaf1诱导的细胞凋亡由流式细胞检测DNA含量来表示。【结果】在30个抗hygromycin的细胞株中,免疫印迹法筛选出5个明显由doxycycline调控诱导表达Xaf1的细胞株,免疫荧光显微镜检测显示doxycycline诱导Xaf1表达于细胞核内。流式细胞检测Xaf1于8h开始诱导Saos细胞凋亡,凋亡率最高约20%,而且不影响细胞周期。【结论】Xaf1-Saos诱导细胞株是研究Xaf1调节肿瘤细胞凋亡机制的良好细胞模型;Xaf1是一种核蛋白,能独立诱导肿瘤细胞凋亡。

LINE-1 ORF-1p对肝脏肿瘤细胞系和肝源永生化细胞系增殖的调控作用

目的研究反转座子LINE-1编码蛋白LINE-1 ORF-1p对肝脏肿瘤细胞系以及肝源永生化细胞系增殖能力的影响。方法构建针对LINE-1 ORF-1编码序列的siRNA表达载体(LINE-1 ORF-1p psilence2.1-U6-siRNA),转染肝脏肿瘤细胞系Bel-7402、SMMC-7721、HepG2和肝源永生化细胞系LO2。采用Western blotting检测LINE-1 ORF-1p siRNA表达载体对LINE-1 ORF-1编码蛋白LINE-1 ORF-1p表达的影响,采用MTT法检测LINE-1 ORF-1p表达受抑对细胞增殖的影响。结果在肝脏肿瘤细胞HepG2、Bel-7402、SMMC-7721和肝源永生化细胞LO2中,转染LINE-1 ORF-1p siRNA表达载体均能降低LINE-1 ORF-1p的表达水平,并从第3天起显著抑制前述细胞的增殖(P<0.05),其抑制率分别为63%、51%、40%、43%。结论抑制LINE-1 ORF-1p蛋白表达后可使肝脏肿瘤细胞系和永生化细胞系的增殖受抑。

Doxycycline抑制大肠癌LS174T细胞侵袭的体外实验研究

目的:观察多西环素(Doxycycline)在体外对LS174T侵袭能力的抑制作用,并尝试探讨该抑制作用的分子机制。方法:1)MTT法观察Doxycycline对LS174T细胞粘附力的影响;Transwell小室法检测不同浓度Doxycycline对细胞侵袭和运动能力的抑制作用;2)RT-PCR法检测不同浓度Doxycycline作用48h后,MMP2的mRNA表达情况,同时明胶酶谱法检测MMP2分泌。结果:1)Doxycycline能够以剂量依赖方式抑制大肠癌LS174T细胞的体外运动和侵袭能力,但不影响其粘附能力;2)Doxycycline能够抑制LS174T细胞MMP2的mRNA表达。结论:Doxycycline在体外能够有效地抑制大肠癌LS174T细胞的侵袭、转移,其中MMP2是抑制大肠癌细胞LS174T的一个有效靶点。

生长抑素对人肝癌HepG2细胞增殖及cyclinD1、cyclinE蛋白表达的影响

目的探讨生长抑素治疗肝癌的作用机制。方法取对数生长期HepG2细胞以不含血清的培养液使其周期同步化，以含血清培养液继续培养24h后随机分为观察Ⅰ、Ⅱ、Ⅲ组及对照组，前三组分别加入质量浓度为100、200、400μg／（kg·d）的生长抑素，对照组加入等体积RPMll640培养液24—72h。MTT比色法观察各组细胞增殖抑制率，流式细胞仪检测细胞周期分布，免疫组化法检测周期素D1（cyclinD1）、周期素E（cyclinE）蛋白表达。结果观察Ⅰ、Ⅱ、Ⅲ组不同时间点细胞增殖抑制率均显著高于对照组，且同一时间点观察Ⅲ组〉观察Ⅱ组〉观察I组，同组中72h〉48h〉24h（P〈0．05、0．01）；观察Ⅰ、Ⅱ、Ⅲ组G，期细胞比例均显著高于对照组，观察Ⅱ、Ⅲ组S期细胞比例均显著低于对照组（P〈0．05、0．01）；观察Ⅰ、Ⅱ、Ⅲ组cyclinD1、cyclinE蛋白水平均显著低于对照组，且观察Ⅲ组〈观察Ⅱ组〈观察Ⅰ组（P〈0．05、0．01）。结论生长抑素可通过下调cyclinD1、cyclinE表达抑制HepG2细胞增殖，此可能为其治疗肝癌的作用机制之一。

Doxycycline诱导表达Msx2-GFP的鼠晶状体上皮Alpha-TN4细胞株的建立

目的利用基因开关调节系统(Tet-on),拟建立由doxycycline调控表达的Msx2诱导细胞株,经与SWISS-2DPAGEDATA比对,发现差异蛋白点。方法向鼠晶状体上皮细胞(Alpha-TN4)中稳定转染质粒Msx2-GFP-M2和TAP-GFP-M2,转染后的细胞经过G418筛选,挑出doxycycline诱导Msx2-GFP表达且具有较低背景的诱导细胞株M8,将空载体细胞株T9作为阴性对照细胞株。并对2组细胞行二维凝胶电泳(2-DE)及基因表达微阵列进行分析。结果从二维凝胶电泳图谱上获得蛋白质斑点。对照组T9检测到5389个斑点,实验组M8检测到5460个斑点。经与SWISS-2DPAGEDATA比对,发现差异蛋白点。经基因表达微阵列分析发现,与晶状体及白内障疾病相关的差异基因为Col3α1,并在RNA水平进行了验证。结论Msx2基因过表达对Alpha-TN4蛋白质表达谱有影响,其中差异基因Col3α1与晶状体及白内障疾病相关。

HIGH DENSITY CULTIVATION OF A RECOMBINANT CD－1 CELL LINE PRODUCING PROUROKINASE USING A BIOSILON MICROCARRIER CULTURE SYSTEM

CD-1, a genetically-engineered CHO cell line, was cultivated with a Biosilon microcarrier culture system.We successfully cultivated CD-1 cells to a very high density (over1×107cells/ml). Prourokinase was stably secreted at about 180 IU/ 1e6 cells/24 h. Experiments showed that CD-1 cells growing on Biosilon microcarriers were able to spontaneously release from the microcarriers, then reatthch and proliferate on fresh microcarriers. This makes it very easy to scale up preduction. The microcarriers could be reused several times without affecting adhesion. proliferation and prourokinase secretion. With CMPECC membrane radial flow chromatography and MPG chromatography, the prourokinase in conditioned medium could be purified to a specific activity of 1×105 IU/mg of protein. The purification factor was about 600 fold, and approxiamately 90 % of the biological activity was recovered.