MAPK通路在红托竹荪多糖诱导人胃癌MKN-45细胞凋亡中的作用机制研究

目的:研究红托竹荪多糖对人胃癌MKN-45细胞增殖与凋亡的影响,并基于丝裂原激活的蛋白激酶(MAPK)信号通路探讨其可能的作用机制。方法:体外培养MKN-45细胞,分为对照组,红托竹荪多糖低、中及高剂量组,采用终浓度分别为0、4、6及8 mg/mL的红托竹荪多糖作用于细胞48 h后,采用细胞计数法检测红托竹荪多糖对人胃癌MKN-45细胞增殖的影响;采用倒置显微镜观察不同浓度的红托竹荪多糖作用于人胃癌MKN-45细胞48 h后细胞形态学的变化。设立实验组的红托竹荪多糖终浓度为8 mg/mL,采用膜联蛋白V-异硫氰酸荧光素/碘化丙啶双染色流式细胞技术检测细胞的凋亡率;采用流式细胞术检测细胞周期分布;采用蛋白质印迹法检测红托竹荪多糖作用胃癌细胞后p38蛋白激酶(p38)、磷酸化p38蛋白激酶(p-p38)、细胞外调节蛋白激酶(ERK)、磷酸化细胞外调节蛋白激酶(p-ERK)、C-JUN氨基末端激酶(JNK)、磷酸化C-JUN氨基末端激酶(p-JNK)、B淋巴细胞瘤-2蛋白(Bcl-2)和活化的半胱氨酸蛋白酶-3(cleaved Caspase-3)蛋白的表达,即与3-磷酸甘油醛脱氢酶(GADPH)灰度值比值。结果:作用48 h后,不同浓度的红托竹荪多糖(4、6及8 mg/mL)对人胃癌MKN-45细胞增殖的抑制率分别为(8.27±5.99)%、(21.83±5.77)%和(56.95±5.21)%;在检测的浓度范围下,随着浓度的升高,红托竹荪多糖对MKN-45细胞增殖的抑制率逐渐升高。倒置显微镜下显示,经8 mg/mL的红托竹荪多糖作用48 h后,MKN-45细胞密度与对照组相比明显减少。流式细胞术检测结果显示,与对照组相比,实验组人胃癌MKN-45细胞凋亡率显著升高(P<0.05);细胞周期结果显示,实验组G_(1)期细胞比例明显减少(P<0.05),G_(2)期细胞比例明显增多(P<0.05),S期细胞比例明显减少(P<0.05);蛋白质印迹法结果显示,与对照组相比,实验组MKN-45细胞中cleaved Caspase-3的表达有升高趋势(P<0.05),Bcl-2的表达有降低趋势(P<0.05),p-P38/P38比值、p-ERK/ERK比值与p-JNK/JNK比值均低于对照组(P<0.05),上述差异均有统计学意义。结论:红托竹荪多糖在体外能抑制人胃癌MKN-45细胞增殖并诱导细胞凋亡,使肿瘤细胞阻滞在G_(2)/M期,其作用可能通过调控MAPK信号通路实现。

Apoptosis mechanisms of human gastric cancer cell line MKN-45 infected with human mutant p27

AIM: To explore the inducing effect of human mutant p27 gene on the apoptosis of the human gastric cancer cell line MKN-45 and its associated mechanisms. METHODS: The recombinant adenovirus Ad-p27mt was constructed to infect the human gastric cancer cell line MKN-45. Using flow cytometry, TUNEL assay and DNA fragment analysis, we measured the apoptotic effect of Ad-p27mt on the human gastric cancer cells. RESULTS: Ad-p27mt was successfully constructed and the infection efficiency reached 100%. After 18 h of infection, we observed an apoptotic hypodiploid peak on the flow cytometer before G1-S and apoptotic characteristic bands in the DNA electrophoresis. The apoptotic rate detected by TUNEL method was significantly higher in the Ad-p27mt group (89.4±3.12%)compared to the control group (3.12±0.13%, P ＜ 0.01).CONCLUSION: Human mutant p27 can induce apoptosis of the human gastric cancer cells in vitro.

Inhibition of human telomerase in MKN-45 cell line by antisense hTR expression vector induces cell apoptosis and growth arrest

AIM: To investigate the effects of antisense humantelomerase RNA (hTR) on the biologic behavior of humangastric cancer cell line: MKN-45 by gene transfection and itspotential role in the gene therapy of gastric cancer.METHODS: The hTR cDNA fragment was cloned from MKN-45 through RT-PCR and subcloned into eukaryoticexpression vector (pEF6/V5-His-TOPO) in cis-direction ortrans-direction by DNA recombinant methods. Theconstructed sense, antisense and empty vectors weretransfected into MKN-45 cell lines separately by lipofectin-mediated DNA transfection technology. After drugselection, the expression of antisense hTR gene in stabletransfectants and normal MKN-45 cells was detected by RT-PCR, the telomerase activity by TRAP, the apoptoticfeatures by PI and Hoechst 33258 staining, the cell cycledistribution by flow cytometry and the population doublingtime by cell counting. Comparison among the stabletransfectants and normal MKN-45 cells was made.RESULTS: The sense, antisense hTR eukaryotic expressionvectors and empty vector were successfully constructed andproved to be the same as original design by restrictionendonuclease analysis and sequencing. Then, they weresuccessfully transfected into MKN-45 cell lines separatelywith lipofectin. The expression of antisense hTR gene wasonly detected in MKN-45 cells stably transfected withantisense hTR vector (named as MKN-45-ahTR) but not inthe control cells. In MKN-45-ahTR, the telomerase activitywas inhibited by 75 %, the apoptotic rate was increased to25.3 %, the percentage of cells in the G0/G1 phase wasincreased to 65 %, the proliferation index was decreased to35 % and the population doubling time was prolonged to 35.3hours. However, the telomerase activity, the apoptotic rate,the distribution of cell cycle, the proliferation index and thepopulation doubling time were not different among the controlcells.CONCLUSION: Antisense hTR can significantly inhibittelomerase activity and proliferation of MKN-45 cells andinduce cell apoptosis. Antisense gene therapy based onteiomerase inhibition can be a potential therapeuticapproach to the treatment of gastric cancer.

Effects of mifepristone on invasive and metastatic potential of human gastric adenocarcinoma cell line MKN-45 in vitro and in vivo

AIM： To investigate the effects of mifepristone on the invasive and metastatic potential of human gastric adenocarcinoma cell line MKN-45 and its mechanisms. METHODS: After incubation with various concentrations of mifepristone (5, 10, 20 umol/L), the adhesion to artificial basement membrane, Matrigel, and the migration of MKN-45 cells were assayed using MTT assay and Transwell cell culture chambers, respectively. Enzyme- linked immunoabsorbent assay (ELISA) and flow cytometry were used to determine the expression of vascular endothelial growth factor (VEGF) and integrin 133 in the cells. After subcutaneous transplantation of MKN-45 cells in nude mice, mifepristone (50 mg/kg.d) was administrated subcutaneously for 8 wk to assess its effects on tumor metastasis. Immunohistochemical analysis was used to detect the expression of VEGF and microvascular density (MVD) in xenografted tumors. RESULTS: Mifepristone dose-dependently inhibited the heterotypic adhesion to Matrigel of MKN-45 cells. The inhibition was accompanied by a significant down-regulation of integrin 133 expression in the cells. After incubation with 5, 10, 20 umol/L mifepristone, the number of migrated MKN-45 cells was 72+8, 50+6, 41+5 in experiment group, and 94+16 in control group (P<0.01). Meanwhile, secreted VEGF protein of MKN-45 cells in mifepristone-treated group (14.2+2.9, 8.9+3.1, 5.4+2.1 ng/g per liter) was significantly lower than that in control group (22.7+4.3 ng/g per liter, P<0.01). In vivo, mifepristone decreased the number of metastatic foci in lungs of nude mice and down-regulated the expression of VEGF and MVD in the xenograted tumors. CONCLUSION: Mifepristone can effectively inhibit the invasive and metastatic potential of human gastric adenocarcinoma cell line MKN-45 in vitro and in vivo through inhibition of heterotypic adhesion to basement membrane, cell migration and angiogenesis.

INHIBITORY EFFECTS OF MIFEPRISTONE ON THE GROWTH OF HUMAN GASTRIC CANCER CELL LINE MKN-45 IN VITRO AND IN VIVO

Objective To explore the effects of mifepristone on the growth of human gastric cancer cell line MKN-45 and its possible mechanisms. Methods In situ hybridization was used to detect the expression of progesterone receptor (PR) mRNA in MKN-45 cells. Proliferation, cell cycle distribution, and the expression of Bcl-xL and vascular endothelial growth factor (VEGF) of MKN-45 cells incubated with various concentrations of mifepristone (1, 5, 10, and 20 μmol/L) were analyzed using MTT reduction assay, flow cytometry, reverse transcription-polymerase chain reaction (RT-PCR), and enzyme-linked immunoab-sorbent assay (ELISA), respectively. After transplantation of MKN-45 cells underneath the skin of athymic mice, mifepristone was administrated with the dose of 50 mg/(kg·d) for 6 weeks to evaluate the tumor growth. Apoptosis and the expression of proliferating cell nuclear antigen (PCNA) in xenografted tumors were detected using transmission electron microscopy and immunohistochemical staining, respectively. Results PR mRNA was highly expressed in cultured MKN-45 cell. Mifepristone dose-dependently inhibited the pr-oliferation of MKN-45 cells, and the inhibitory rate was dramatically increased from 7.21% to 47.23%. The inhibitory effect was accompanied by a dose-dependent increase in the percentage of cells in G 0 /G 1 phase, and with a concurrent decrease in the proportion of S- and G 2 /M-phase cells and the proliferative index from 57.65% to 24.54%. Meanwhile, mifepristone down-regulated the expression of Bcl-xL and VEGF in a dose-dependent manner. In vivo, mifepristone effectively inhibited the growth of xenografted tumors in nude mice (55.14% for inhibitory rate), induced apoptosis, and down-regulated PCNA expression in gastric cancer. Conclusion Mifepristone exerts significant growth inhibitory effects on PR-positive human MKN-45 gastric cancer cells via multiple mechanisms, and may be a beneficial agent against the tumor.

TRIM45靶向IGF-1R抑制乳癌MCF-7细胞增殖和迁移的机制

目的探究三结构域蛋白45(TRIM45)通过靶向胰岛素样生长因子1受体(IGF-1R)抑制人乳癌MCF-7细胞增殖和迁移的作用机制。方法将人乳癌MCF-7细胞分为TRIM45过表达组、空载对照组及阴性对照组。通过细胞增殖实验及划痕实验进行细胞增殖及迁移能力检测,采用蛋白质免疫印迹(WB)法检测自噬相关蛋白p62、微管相关蛋白Ⅰ轻链3B(LC3B)、自噬相关蛋白8(ATG8)的表达,通过免疫沉淀实验分析TRIM45与IGF-1R的结合,采用WB法检测促增殖蛋白IGF-1R和簇集蛋白(CLU)的表达。结果与空载对照组相比较,TRIM45过表达组不同时间的细胞增殖率及迁移率均显著降低(F=19.87~177.91,P<0.05)。与空载对照组相比较,TRIM45过表达组细胞自噬相关蛋白p62的表达显著降低,LC3B和ATG8的表达显著增加(F=22.97~113.50,P<0.05)。TRIM45可以与IGF-1R结合,并且TRIM45过表达组细胞IGF-1R及CLU蛋白表达较空载对照组显著降低(F=51.06、30.45,P<0.05)。结论TRIM45可以与IGF-1R结合,抑制IGF-1R及CLU的表达,诱导乳癌细胞自噬,抑制乳癌细胞的增殖和迁移能力。

Are CD45RO^(+)and CD45RA^(-)genuine markers for bovine memory T cells?

Effective vaccination in duces memory T cells,which protect the host against pathogen re-infecti ons.Therefore,detection of memory T cells is essential for evaluating vaccine efficacy,which was originally dependent on cytokine induction assays.Currently,two isoforms of CD45 tyrosine phosphatase,CD45RO expression and CD45RA exclusion(CD45RO^(+)/CD45RA^(-)) are used extensively for detecting memory T cells in cattle.The CD45RO^(+)/CD45RA^(-) markers were first established in humans around three decades ago,and were adopted in cattle soon after.However,in the last two decades,some published data in humans have challenged the initial paradigm,and required multiple markers for identifying memoryT cells.On the contrary,memoryT cell detection in cattle still mostly relies on CD45RO^(+)/CD45RA^(-)despite some con troversial evidence.In this review,we summarized the current literature to exami ne if CD45RO^(+)/CD45RA^(-)are valid markers for detecting memoryT cells in cattle.It seems CD45RA and CD45RO(CD45RA/RO)as markers for identifyi ng bovine memoryT cells are questi on able.

The histone deacetylase inhibitor trichostatin A induces cell cycle arrest and rapid upregulation of gadd45β in LS174T human colon cancer cells

Histone deacetylase (HDAC) inhibitors are considered as promising therapeutic agents against several malignant diseases because they inhibit cancer cell proliferation. The stress sensor genes of the growth arrest and DNA damage-inducible protein (gadd45) family exhibit disordered expression in several types of malignant diseases and are thus a novel target for cancer therapy. However, there have been only few investigations of whether HDAC inhibitors affect the expression of gadd45 genes. We examined the effects of a HDAC inhibitor, trichostatin A (TSA), on the time-dependent expression of gadd45 genes in the human colon cancer cell line LS174T. Addition of TSA to LS174T cells induced inhibition of cell proliferation by arresting the cell cycle. We found that TSA treatment of LS174T cells induced rapid upregulation of gadd45β mRNA expression within 15 min, reaching a peak level at 3 h. Although the time-dependent expression pattern of gadd45β mRNA was similar to that of gadd45β mRNA, the peak level of gadd45β was lower than that of gadd45β. TSA treatment also upregulated the mRNA level of p21Waf1/Cip1, a prolif- eration inhibitor, after 3 h, but downregulated the mRNA levels of cyclin D1, a proliferation inducer, after 3 h, and of c-Myc after 1 h. TSA treatment induced a certain level of apoptosis, but the mRNA level of p53, a potent apoptosis inducer, was down-regulated after 3 h. These results suggest that the up-regulation of p21Waf1/Cip1 and apoptosis was independent of p53 and that the early upregulation of gadd45β gene, which precedes the upregulation of p21Waf1/Cip1 and the downregulation of cyclin D1, are important in TSA-treated LS174T cells.

参芪抑瘤方药物血清对胃癌MKN-45细胞周期阻滞及抗侵袭转移的影响

目的 探讨不同浓度参芪抑瘤方药物血清对胃癌MKN-45 细胞周期阻滞及抗侵袭转移作用的相关机制.方法 60 只SPF 级Wistar 大鼠,随机分为对照组和参芪抑瘤方低、中、高剂量组,每组15 只.参芪抑瘤方低、中、高剂量组分别给予0.25、0.50、1.00 g 原药材/mL 药液灌胃,空白组给予等量饮用水灌胃,每日2 次,连续7 d,末次灌胃2 h 后取血,分离血清.MKN-45 细胞经不同浓度药物血清处理后,流式细胞术检测细胞周期,免疫组化检测COX-2、PTEN 蛋白表达.结果 药物血清干预后细胞G0～G1 期比例增加,S 期比例减少;药物血清可降低MKN-45 细胞COX-2 蛋白阳性表达率,升高PTEN 蛋白阳性表达率（P〈0.05）.结论 参芪抑瘤方药物血清阻滞细胞周期及抗侵袭转移作用可能与影响COX-2、PTEN 蛋白表达有关.

藤梨根提取物对人胃癌MKN-45细胞增殖及凋亡的影响

目的:探讨太白山藤梨根提取物(Radix Actinidiae extractive,RAE)在体外对胃癌MKN-45细胞增殖与凋亡的影响。方法:用0.01-100μg/ml浓度范围内的RAE和胃癌MKN-45细胞共培养24、48、72、96小时,采用MTT法检测RAE对MKN-45细胞增殖的影响;用流式细胞仪检测其对MKN-45细胞凋亡及细胞周期分布的影响;DNA琼脂糖凝胶电泳检测细胞凋亡。结果:RAE在体外能够显著抑制胃癌MKN-45细胞的增殖,且呈现浓度和时间依赖性;RAE对胃癌细胞的作用表现为周期特异性,使细胞阻滞于G0/G1期,进一步诱导细胞凋亡。对照组凋亡率为0.53%,1μg/ml、10μg/ml、100μg/ml浓度的RAE干预胃癌细胞48小时后均出现凋亡峰,细胞凋亡率分别为3.27%、8.97%、12.6%。DNA琼脂糖凝胶电泳检测细胞凋亡,不同浓度RAE处理的细胞样品中均可看到梯形凋亡条带,并呈现浓度依赖性。结论:RAE在体外对人胃癌MKN-45细胞有显著的抑制细胞增殖及诱导细胞凋亡作用,其作用机制可能是使胃癌细胞周期阻滞于G0/G1期。

天花粉蛋白诱导胃癌细胞MKN-45凋亡的研究

目的 :研究天花粉蛋白（ trichosanthin,TCS）对胃癌细胞的作用，探讨其治疗胃癌的可能作用机制。方法 :采用生长曲线、集落形成实验、 MTT法、电镜、 TUNEL染色和流式细胞仪等技术，研究 TCS对胃癌细胞 MKN－ 45的增殖抑制和诱导凋亡作用。结果： TCS能够明显抑制胃癌细胞 MKN－ 45的生长和集落形成， 1μ g/ml和 0.1μ g/ml TCS作用 MKN－ 45后，细胞集落形成率分别为 (6.63± 1.31)％和 (14.68± 1.27)％，明显低于对照组的 (23.67± 2.76)％

E2F-1基因真核表达载体的构建及其对胃癌细胞株MKN-45增殖的影响

背景与目的:E2F-1基因在多种肿瘤细胞中过表达,并表现出抑制或促进肿瘤细胞增殖的不同特性。本研究通过构建E2F-1基因真核表达载体,分析E2F-1过表达对胃腺癌细胞株MKN-45的影响。方法:巢式聚合酶链反应(polymerase chain reaction,PCR)扩增E2F-1基因片段,用pCMV-HA载体构建真核重组质粒,转染MKN-45细胞(转染COS-7细胞用以鉴定所构建的载体)。Western blot检测转染情况,并通过克隆形成实验、MTS法检测细胞增殖情况,流式细胞仪分析细胞周期,观察E2F-1过表达对MKN-45细胞的影响。结果:pCMV-E2F1-HA重组质粒成功转染MKN-45细胞。转染pCMV-E2F1-HA的MKN-45细胞形成的克隆数为4.7±1.8,明显少于转染空载体组的30.2±6.7(P<0.01)。转染pCMV-E2F1-HA的MKN-45细胞增殖随时间而减慢,第5、6、7天的细胞增殖率分别为73.5%、63.5%和56.1%,明显低于转染空载体组(P<0.01)。与转染空载体组相比,表达E2F-1基因的MKN-45细胞在G0/G1期所占比例明显提高(71.4%vs.59.7%,P<0.05),S期所占比例明显下降(18.7%vs.30.7%,P<0.05)。结论:成功构建E2F-1基因真核表达载体,E2F-1过表达可抑制MKN-45细胞的增殖。

金龙蛇颗粒对裸鼠原位移植人胃癌MKN-45细胞凋亡的影响

目的：评价金龙蛇颗粒对裸鼠原位移植入胃癌MKN-45细胞的抑制作用.方法：50只裸鼠建立原位移植人胃癌MKN-45细胞模型,随机分为模型组,金龙蛇颗粒高、中、低剂量组和5-FU干预组.各组裸鼠予以相应药物实施干预.观察各组荷瘤裸鼠一般情况,肿瘤生长情况及抑瘤率.流式细胞仪检测肿瘤细胞周期分布及细胞凋亡情况.采用膜联蛋白V-异硫氰酸荧光素/碘化丙啶（Annexin V-fluorescein isothiocyanate/propidium iodide,Annexin V-FITC/PI）双标记染色法鉴别早期凋亡细胞、晚期凋亡细胞和坏死细胞.电镜下观察肿瘤细胞的超微结构变化.结果：金龙蛇颗粒高、中、低剂量组的抑瘤率分别为68.13%、55.94%和50.31%,呈剂量依赖效应,与5-FU干预组抑瘤率比较,差异无统计学意义.金龙蛇颗粒各剂量组肿瘤细胞凋亡率为22.81%～38.54%,亦呈剂量依赖效应,且肿瘤细胞主要被阻滞于G0/G1期.AnnexinV-FITC/PI双标记染色结果显示,金龙蛇颗粒各剂量组以早期凋亡细胞居多,5-FU干预组则以晚期凋亡细胞和坏死细胞居多.结论：金龙蛇颗粒对裸鼠原位移植人胃癌MKN-45细胞具有较好的抑制作用,促进MKN-45细胞凋亡可能是其抗肿瘤治疗的主要作用机制之一.

Smac基因过表达对胃癌细胞株MKN-45化疗敏感性的影响

背景与目的:细胞凋亡异常是肿瘤细胞产生耐药性的关键因素之一。Smac(secondmitochondria-derivedactivatorofcaspases,Smac或称DIABLO)是新近发现的一种凋亡调节基因,在介导化疗药物诱导肿瘤细胞凋亡中起重要作用。本研究旨在观察Smac基因过表达对胃癌细胞株化疗敏感性的影响。方法:采用脂质体GeneSHUTTLE-40介导的方法,将Smac基因转入胃癌细胞MKN-45,RT-PCR和Westernblot法检测癌细胞中Smac的表达;选用顺铂(1、5、10μg/ml)、丝裂霉素(0.1、1、10μg/ml)和姜黄素(10、20、40μmol/L)分别处理转染前后的胃癌细胞,四甲基偶氮唑蓝(MTT)比色法检测细胞增殖活性,倒置显微镜下观察细胞形态变化并摄影,AnnexinV-FITC和碘化丙啶双染色,流式细胞仪检测细胞凋亡。结果:同未转染对照组比较,转染外源性Smac基因后MKN-45细胞SmacmRNA和蛋白表达水平显著增高(P<0.01);各浓度顺铂、丝裂霉素和姜黄素处理24h后,细胞生长抑制率分别增加10.10%～23.80%(P<0.01)、10.01%～15.86%(P<0.01)、11.28%～22.12%(P<0.01),细胞明显变圆、折光增强、漂浮细胞增多,细胞凋亡率分别增加6.7%～20.2%(P<0.01)、5.4%～13.2%(P<0.01)、10.6%～20.1%(P<0.01)。结论:转染外源性Smac基因并使其在胃癌细胞中过表达。

5-氟尿嘧啶气雾对人胃癌细胞MKN-45增殖、凋亡及周期的影响

目的通过体外模拟5-氟尿嘧啶(5-Fu)腹腔气雾化疗环境,评价5-Fu雾化对人胃癌细胞MKN-45增殖、凋亡及周期的影响。方法运用自主研发的气雾化疗仪将5-Fu雾化,体外模拟腹腔气雾化疗环境,对胃癌细胞进行处理,维持气雾环境压力为8mmHg,作用时间为30min,并设生理盐水雾化作为对照,处理后用MTT法检测细胞增殖情况,流式细胞仪检测细胞凋亡和细胞周期。结果 MTT结果显示,5-Fu气雾化疗组杀伤率显著高于生理盐水组[(31.13±3.51)%比(4.65±1.99)%,P<0.001];流式细胞结果显示,与生理盐水组相比,5-Fu气雾化疗组细胞凋亡率升高[(12.00±0.92)%比(2.65±0.52)%,P<0.001)],G1期细胞增多[(51.83±1.95)%比(36.41±2.33)%,P<0.001]、S期细胞减少[(16.72±2.36)%比(45.20±3.27)%,P<0.001],差异均有统计学意义。结论 5-Fu气雾能有效抑制胃癌细胞的增殖并诱导凋亡,使细胞阻滞于G1期,为气雾化疗的临床应用提供实验依据。

丹参酮IIa诱导人胃癌细胞MKN-45凋亡及对端粒酶活性的影响

目的考察丹参酮IIa(tanshinone IIa,Tan IIa)诱导人胃癌细胞的凋亡作用,以及对端粒酶活性的影响。方法不同浓度TanⅡa处理人胃癌细胞株MKN-45后,显微镜下观察胃癌细胞形态变化,应用Annexin V/PI双重染色方法检测细胞凋亡比例,并用凋亡相关抗体检测通路情况,用RT-PCR以及TRAP-PCR法分别对胃癌细胞端粒酶基因hTert和端粒酶活性进行检测。结果TanⅡa处理胃癌细胞后,DAPI染色显示,细胞核内染色质聚缩,细胞核碎裂并有凋亡小体产生,提示TanⅡa诱导胃癌MKN-45细胞凋亡。Annexin V/PI双染结果显示,凋亡比例随化合物浓度提高而增加,40μM下晚期凋亡比例达到(45.02±6.48)%。凋亡相关蛋白的检测显示,PARP和Caspase-3活化,细胞色素C水平增加,而Caspase-8则无显著变化。同时TRAP-PCR结果显示,Tan IIa在诱导细胞凋亡的同时伴随端粒酶活性下调,并在40μM下显著抑制hTert基因的表达。结论 TanⅡa对人胃癌细胞具有明显诱导细胞凋亡作用,且可能通过激活内源性途径引起细胞凋亡。TanⅡa还可抑制端粒酶活性和hTERT基因表达,这些可能是其发挥抗癌作用的重要机制之一。

不同浓度苦参碱、大蒜素对人胃癌细胞株MKN-45杀伤作用的实验研究

目的:观察不同浓度苦参碱、大蒜素对人胃癌细胞株MKN-45体外生长的影响。方法:体外培养人胃癌细胞株MKN-45,分别用不同浓度的苦参碱、大蒜素处理,采用CCK-8法检测MKN-45细胞的生长情况。结果:不同浓度的苦参碱及大蒜素作用于MKN-45细胞后,对其增殖均表现出了明显的抑制作用,并表现出浓度与作用时长的依赖性,最高抑制值分别达到了96.82%和93.44%。结论:苦参碱及大蒜素可以抑制胃癌MKN-45细胞的增殖,且与作用时间、剂量呈正相关。

人参皂甙Rg3刺激淋巴细胞CD4上调以及对胃癌细胞MKN-45的杀伤作用

目的探讨人参皂甙Rg3对淋巴细胞的免疫刺激作用及其对胃癌细胞MKN-45的影响。方法采用梯度密度分离法分离正常人淋巴细胞,经人参皂甙Rg3刺激后流式细胞术检测人参皂甙Rg3对正常人淋巴细胞CD4表达的影响;用MTT法测定人参皂甙Rg3对MKN-45抑制作用;HE染色法观察人参皂甙Rg3诱导MKN-45的凋亡作用。结果人参皂甙Rg3促进正常人淋巴细胞CD4表达明显高于正常对照组(P<0.05);人参皂甙Rg3对MKN-45抑制率、凋亡率与正常对照组比较有显著性差异(P<0.05)。结论人参皂甙Rg3具有刺激淋巴细胞CD4上调的作用以及抑制MKN-45细胞生长的作用。

过表达miR-26b抑制MKN-45人胃癌细胞的增殖

目的构建miR-26b过表达载体,观察其对MKN-45人胃癌细胞增殖的影响。方法合成miR-26b DNA寡聚核苷酸单链,经退火形成双链;用限制性内切酶EcoRⅠ和HindⅢ对pc DNATM6.2-GW-miR真核表达载体进行双酶切(大片段),纯化后与之前退火形成的DNA双链连接,转化至大肠杆菌感受态细胞DH5α,扩增后提取质粒,经DNA测序和BLAST比对,验证其是否构建成功;将成功构建的pc DNATM6.2-GW-miR-26b载体瞬时转染MKN-45人胃癌细胞,采用实时定量PCR检测miR-26b的表达水平,Western blot法检测细胞分裂周期蛋白6(CDC6)蛋白,MTT法检测细胞增殖的变化。结果通过DNA测序BLAST比对结果显示成功构建了miR-26b的真核表达载体;瞬时转染MKN-45细胞后,实时定量PCR结果显示miR-26b的表达水平显著增加;Western blot结果表明过表达miR-26b明显抑制CDC6蛋白的表达,MTT法显示过表达miR-26b能显著抑制MKN-45细胞的增殖。结论过表达miR-26b可抑制MKN-45人胃癌细胞的增殖。

天花粉蛋白诱导胃癌细胞MKN-45凋亡中P53、Bcl-2、c-myc蛋白表达变化

目的 选用对天花粉蛋白敏感的胃癌细胞株MKN 45 ,研究天花粉蛋白抗肿瘤机制。方法 免疫组化法测定凋亡相关基因 (P5 3、Bcl 2、c myc)的表达变化。 结果 胃癌细胞MKN 45经天花粉蛋白 (1μg/ml,2 4、48h)处理后 ,凋亡相关基因P5 3、Bcl 2、c myc表达未出现显著性改变。经 5 μg/ml的天花粉蛋白处理 2 4h后 ,得到相同结论。但当MKN 45细胞经 5 μg/ml的天花粉蛋白处理 48h后 ,发现野生型P5 3蛋白表达增加 ,而Bcl 2、c myc蛋白表达未出现显著性改变。 结论 天花粉蛋白可诱导MKN 45细胞凋亡 ,可能与上调野生型P5 3基因的表达有关。