有丝分裂阻滞缺陷蛋白2选择性剪接体MAD2β在胃癌细胞多药耐药机制中的作用

目的观察有丝分裂阻滞缺陷蛋白2(mitotic arrest deficient protein 2, MAD2)基因的选择性剪接体MAD2β在人胃癌多药耐药性形成过程中的作用机制.方法从耐阿霉素人胃癌细胞系SGC7901/ADR中提取总RNA,通过RT-PCR获得MAD2β全长编码cDNA,并克隆至pUCm-T载体,正向亚克隆插入真核表达载体pcDNA3.1中.以脂质体介导pcDNA3.1/MAD2β真核表达载体转染胃腺癌细胞SGC7901.以体外药敏试验检测转染MAD2β的胃癌细胞及其对照组细胞对化疗药物的敏感性.通过流式细胞仪检测MAD2β基因转染组和对照组胃癌细胞在细胞周期中的分布和细胞内阿霉素的荧光强度.结果 RT-PCR扩增获得约0.53 kb片段,DNA序列测定证实为MAD2的一种选择性剪接形式,命名为MAD2β.重组正义真核表达载体pcDNA3.1/MAD2β瞬时转染SGC7901细胞,经MTT法证实,转染细胞SGC7901/MAD2β对化疗药物阿霉素、长春新碱和丝裂霉素的耐药性增强.与SGC7901/pcDNA3.1比较,阿霉素大剂量短期作用后,SGC7901/MAD2β细胞内的平均荧光强度比对照组低(P<0.05).结论 MAD2β基因在一定程度上增强了人亲本胃癌细胞SGC7901对化疗药物的耐受性,其可能的机制为肿瘤细胞在化疗药物作用下,有丝分裂出现异常,耐药细胞通过调控MAD2基因产生不同的选择性剪接形式, 降低MAD2的活性或改变其功能,以通过纺锤体检测点并继续存活.     

Anti-proliferation effects of Twist gene silencing in gastric cancer SGC7901 cells

AIM:To study the role of Twist gene in gastric cancer by gene silencing,including the potential of induction of apoptosis,cell cycle arrest,and proliferation inhibition in human malignant gastric SGC7901 cells.METHODS:The expression level of Twist in gastric cancer samples was measured by immunohistochemistry.The effects of Twist gene silencing were detected at both m RNA and protein levels by RT-PCR and Western blot.We also evaluated the cell proliferation and apoptosis by CCK-8 assay and flow cytometry.We determined the activity of caspase-3 and caspase-9 with a caspase activity assay kit.Cell cycle distribution was analyzed by flow cytometry.Cell migration and invasion ability was evaluated by wound scratch assay and Boyden chamber assay.RESULTS:Twist protein was highly expressed in gastric cancer samples.Twist gene silencing significantly induced apoptosis,cell cycle arrest at G0/G1 phase,proliferation inhibition,and reduced the ability of migration and invasion in human gastric cancer SGC7901 cells.Meanwhile,both caspase-3 and caspase-9 were activated.CONCLUSION:The Twist gene could serve as a potential molecular target for gene therapy of gastric cancer with targeted small interfering RNA.     

黄连素对人胃癌细胞SGC7901凋亡影响的研究

目的:探讨黄连素对人胃癌细胞SGC7901凋亡的影响。方法:MTS法检测不同浓度的黄连素(100、150、200μmol/L)对胃癌细胞的抑制作用,Hoechst 33258染色检测不同浓度的黄连素(100、150、200μmol/L)对细胞凋亡的影响;Real Time Q-PCR检测胃癌细胞中Cleaved Caspase-3、Bcl-2、Bax的mRNA表达;Western blot检测胃癌细胞中Cleaved Caspase-3、Bcl-2、Bax的蛋白表达。结果:不同浓度的黄连素能显著降低人胃癌细胞SGC701活性(P<0.05,P<0.01),促进其凋亡,升高Cleaved Caspase-3、Bax的mRNA和蛋白表达水平(P<0.05,P<0.01),降低Bcl-2的mRNA和蛋白表达水平(P<0.05,P<0.01)。结论:不同浓度的黄连素可诱导胃癌细胞凋亡,其机制可能与升高Cleaved Caspase-3、Bax的表达,降低Bcl-2的表达有关。     

维生素E琥珀酸酯抑制人胃癌细胞生长作用的研究

目的与方法：本实验采用体外细胞培养的方法,研究了维生素Ｅ琥珀酸酯（ＶＥＳ）对人胃癌ＳＧＣ－７９０１细胞生长和ＤＮＡ合成的影响,并进行了细胞亡形态学观察。结果：ＶＥＳ对ＳＧＣ－７９０１细胞生长和ＤＮＡ合成有明显抑制作用,并呈现剂量－－效应关系。同时,ＶＥＳ也诱导ＳＧＣ－７９０１细胞凋亡。结论：上述结果提示在离体条件下,ＶＥＳ通过抑制细胞ＤＮＡ合成及诱导细胞凋亡亡抑制ＳＧＣ－７９０１细胞生长。     

阿帕替尼通过抑制HMGA2增强顺铂对胃癌的抗瘤作用

目的：探讨阿帕替尼（apatinib,APA）联合顺铂（cisplatin,DDP）对胃癌（gastric carcinoma,GC）细胞增殖、侵袭和迁移 能力的影响及其分子机制。方法：收集2016年1月到2019年6月武威市人民医院手术切除的50例GC患者的癌及癌旁组织标 本,以及GC细胞系MGC803和SGC7901, 用qPCR检测组织中HMGA2和细胞中增殖、迁移及侵袭相关mRNA的表达水平。采 用脂质体转染技术, 将pcHMGA2转染MGC803和SGC7901细胞,经分别用不同浓度的DDP和APA处理,分为NC、pcHMGA2、 pcHMGA2+DDP及pcHMGA2+DDP+APA组, 用Western blotting检测GC细胞中HMGA2蛋白的表达水平,MTT、Transwell小室 法分别检测细胞的增殖、迁移和侵袭能力。结果：HMGA2 mRNA在GC组织中表达水平高于癌旁组织（P<0.05）,且高表达组 GC患者的生存率显著降低（P<0.01）。DDP 显著抑制 MGC803 和 SGC7901 细胞的增殖、侵袭和迁移能力（均P<0.01）; DDP+APA组MGC803和SGC7901细胞的增殖、侵袭和迁移能力显著低于DDP组（均P<0.01）;APA显著增强DDP对GC细胞 HMGA2表达的抑制作用（均P<0.01）;APA通过下调HMGA2表达增强DDP对GC的抗肿瘤性。结论：APA能促进DDP对GC的 抗瘤作用,其分子机制可能是增强DDP对HMGA2表达的抑制作用有关。     

As_2O_3对胃癌细胞SGC7901/ADR阿霉素耐药性逆转作用

目的探讨三氧化二砷(As2O3)对胃癌细胞SGC7901/ADR阿霉素(ADM)耐药性的逆转作用和对Pgp、GSTπ表达的影响。方法以胃癌多药耐药细胞株SGC7901/ADR为靶细胞,用MTT法检测SGC7901/ADR细胞对ADM的敏感性,用流式细胞仪检测细胞内药物浓度及免疫组织化学法检测细胞Pgp、GSTπ表达。结果0.4～0.8μmol/LAs2O3对耐药细胞SGC7901/ADR无明显毒性(P>0.05)。As2O3可下调Pgp、GSTπ表达,提高SGC7901/ADR细胞内ADM浓度,增加SGC7901/ADR细胞对ADM的敏感性。结论As2O3能够抑制SGC7901/ADR细胞Pgp、GSTπ表达,增加细胞内ADM药物浓度而部分逆转其对ADM的耐药性。     

Reversion of multidrug resistance by SKI-II in SGC7901/DDP cells and exploration of underlying mechanisms

In order to investigate whether SKI-II could reverse drug resistance and its possible mechanisms, we treated SGC7901/DDP cells with SKI-II or SKI-II in combination with DDP. Then cell growth, apoptosis, micro- morphological changes, and expression of SphK1, P-gp, NF-kB, Bcl-2 and Bax were assessed by MTT assay, flow cytometry, electron microscopy, immunocytochemistry and Western blot assay respectively. SGC7901/DDP cells were insensitive to cisplatin 2.5 mg/L, but when pretreated with SKI-II, their proliferation was inhibited by cisplatin 2.5mg/L significantly, the inhibition rate increasing with time and dose. The apoptosis rate was also significantly elevated. Expression of SphK1 and P-gp was decreased significantly, Pearson correlation analysis showing significant correlation between the two (r=0.595, P<0.01). Expression of NF-kB and Bcl-2 was decreased significantly, while that of Bax was increased, compared to the control group. There were significant correlations between SphK1 and NF-kB(r=0.723, P<0.01), and NF-kB and Bcl-2(r=0.768, P<0.01). All these data indicated that SKI-II could reverse drug resistance of SGC7901/DDP to cisplatin by down-regulating expression of P-gp and up-regulating apoptosis through down-regulation of SphK1. The increased apoptotic sensitivity of SGC7901/ DDP to cisplatin was due to the decreasing proportion of Bcl-2/Bax via down-regulating NF-kB.     

番茄红素对人胃癌细胞生长的抑制作用

目的通过体外试验研究番茄红素对人胃癌(SGC)-7901细胞生长的作用。方法将番茄红素作用于人胃癌SGC-7901细胞,四甲基偶氮噻唑蓝(MTT)法测定半数抑制浓度(IC50),细胞计数法和集落形成试验检测细胞生长抑制率,3H胸腺嘧啶核苷(3H-TdR)掺入试验测定对细胞DNA合成的影响,倒置显微镜下观察人SGC-7901的形态变化。结果番茄红素作用于人SGC-7901细胞后,细胞生长明显受到抑制,24,48,72,96,120,148和172 h的IC50分别为1.0×10-4,9.2×10-5,2.6×10-5,4.8×10-5,3.5×10-5,4.3×10-5和3.1×10-5mol/L。0.3×10-4,0.5×10-4,10-4mol/L的番茄红素对人SGC-7901 7 d的抑制率分别为64.75%,79.02%,87.13%,SGC-7901的集落形成率分别为(30.2±1.9)%,(22.0±2.1)%,(16.9±2.0)%。番茄红素作用于人SGC-7901 48 h的3H-TdR掺入量分别为(3757.06±114.27),(3148.24±190.23),(2408.32±155.83)cpm,显著低于阴性对照组的(5470.25±217.16)cpm(P<0.01)。不同剂量的番茄红素处理后的细胞变圆,变小,脱落,排列稀疏,部分细胞内出现大小不等的空泡。结论番茄红素在体外能明显抑制人SGC-7901细胞增殖,且存在剂量-效应关系。