A new vector, based on the PolII promoter of the U1 snRNA gene, for the expression of siRNAs in mammalian cells.

Several vectors for the induction of RNA interference in mammalian cells have been described,based mainly on polIII-dependent promoters. They transcribe short hairpin RNAs (shRNA) that,after being processed into short interfering RNAs (siRNAs), mediate the degradation of the target mRNA. Here, we describe the construction of a new siRNA-expressing vector (psiUx) based on the strong and ubiquitous polII-dependent promoter of the human U1 small nuclear RNA (snRNA)gene. In psiUx, the only constraint for the shRNA sequence is a purine at position +1, since specific 3'-end formation is achieved by a box element located downstream of the transcribed region. Several constructs were designed against the lamin A/C target. Depending on the structure of the shRNA transcribed, a preferential or exclusive accumulation of the antisense strand is obtained, thus avoiding possible nonspecific targeting by the sense strand. In all cases tested, very effective siRNAs were produced, thus providing a proof-of-principle that a snRNA-type polII promoter can be used for the expression of siRNAs. We show that psiUx ensures high levels of expression and efficient knock down of the target gene also in stable cell lines.     

长链非编码RNA KCNQ1OT1靶向调控miR-218-5p对结肠癌细胞生物学行为的影响

目的:探讨长链非编码RNA KCNQ1重叠转录物1(lncRNA KCNQ1OT1)调控micro RNA-218-5p(miR-218-5p)对结直肠癌细胞恶性生物学行为的影响及其可能机制。方法:收集2019年1月至4月在宜昌市第一人民医院行根治性结肠癌切除术的30例肿瘤组织和相应的癌旁正常组织。采用实时荧光定量PCR法(qRT-PCR)检测lncRNA KCNQ1OT1,miR-218-5p在结肠癌组织、癌旁正常组织、5种结直肠癌细胞系(HCT-116,SW480,SW620,DLD-1,HT29)及正常结肠上皮细胞系CCD841中的表达水平;干预结肠癌细胞系HCT-116和SW480中lncRNA KCNQ1OT1和miR-218-5p的表达,采用CCK-8法检测结肠癌细胞的增殖,Transwell法检测结肠癌细胞的迁移和侵袭;采用流式细胞术检测细胞周期分布及细胞凋亡率;用Starbase数据库预测lncRNA KCNQ1OT1的靶向miRNA,并用qRT-PCR、双荧光素酶报告基因法验证lncRNA KCNQ1OT1与miR-218-5p的靶向关系。结果:与癌旁正常组织和正常结肠上皮细胞系相比,结直肠癌组织和结直肠癌细胞系中lncRNA KCNQ1OT1的表达水平显著上调,miR-218-5p的表达显著下调(P<0.05);过表达lncRNA KCNQ1OT1促进SW480细胞的增殖、迁移和侵袭,且减少处于G0/G1期的细胞比率,抑制细胞凋亡;在结直肠癌组织中lncRNA KCNQ1OT1的表达水平与miR-218-5p的表达水平呈负相关(r^2=0.437,P<0.001);双荧光素酶报告基因法分析证实lncRNA KCNQ1OT1能特异性结合miR-218-5p,并能降低其表达;过表达miR-218-5p抑制HCT-116细胞的增殖、迁移和侵袭,增加处于G0/G1期的细胞比率,促进细胞凋亡,且miR-218-5p的表达可以抑制由lncRNA KCNQ1OT1过表达引起的细胞增殖、迁移和侵袭能力的增加及凋亡的减少。结论:LncRNA KCNQ1OT1通过靶向调控miR-218-5p表达影响结直肠癌细胞的增殖、迁移和侵袭,促进结直肠癌的发展。     

HLA—DR基因反义RNA导入脐血干／祖细胞对HLA—DR抗原表达的影响

目的：探讨组织相容性抗原Ⅱ类（ＭＨＣ－Ⅱ）基因反义ＲＮＡ是否可调控脐血细胞ＭＨＣ－Ⅱ类基因的表达及降低脐血细胞的免疫原性和脐血细胞移植时发生移植物抗宿主反应（ＧＶＨＲ）的程度。方法：应用分子克隆技术构建了含人ＨＬＡ－ＤＲβ基因的逆转录病毒表达载体，经过狭缝杂交、电泳、酶切分析鉴定，获得了ＨＬＡ－ＤＲβ基因反义ＲＮＡ重组体，用ｌｉｐｏｆｅｃｔｉｎ（脂质体）将重组体导入包装细胞ＰＡ３１７。结果：产重组病毒的细胞ＰＡ３１７的病毒滴度可达１×１０５ｃｆｕ／ｍｌ。用逆转录多聚酶链反应（ＲＴ－ＰＣＲ）可从转染的脐血干细胞中扩增出ＤＲ－β基因ｃＤＮＡ，说明反义ＲＮＡ重组体目的基因已有效表达。用流式细胞仪测定转染的脐血细胞ＨＬＡ－ＤＲ抗原阳性细胞率为２８％（对照组为４５％），其抑制率为３８．２％。结论：导入脐血干细胞的ＨＬＡ－ＤＲ基因反义ＲＮＡ重组体成功地降低了其ＨＬＡ－ＤＲ抗原的表达程度，为临床上降低脐血移植的ＧＶＨＲ提供了理论依据和实验基础。     

长链非编码RNA脑胞质RNA1在前列腺癌中的表达及作用机制

目的探讨长链非编码RNA(lncRNA)脑胞质RNA1(BCYRN1)在前列腺癌中的表达及作用机制。方法选取前列腺癌组织及癌旁正常组织、前列腺癌细胞(PC-3、22RV1、DU-145、LNcap)及前列腺正常肌成纤维基质细胞(WPMY-1),采用qRT-PCR检测BCYRN1表达,分析BCYRN1表达与临床病理特征的关系。选取前列腺癌细胞,分别转染siRNA-NC和siRNA-BCYRN1,CCK8法检测细胞增殖活性,流式细胞仪检测细胞凋亡,Western blot法检测凋亡相关蛋白表达。结果BCYRN1在前列腺癌组织中的表达明显高于癌旁正常组织(P<0.05);与WPMY-1细胞比较,BCYRN1在PC-3、22RV1、DU-145、LNcap细胞中的表达明显增高(P<0.05),其中以PC-3、22RV1为最高。BCYRN1高表达与前列腺癌患者病理分级、T分期及Gleason评分有关(P<0.05),与患者年龄、肿瘤大小、淋巴结转移无关(P>0.05)。与转染siRNA-NC相比较,转染siRNA-BCYRN1后细胞中BCYRN1表达、细胞增殖活性显著降低(P<0.05),同时细胞凋亡率显著增高(P<0.05)。与转染siRNA-NC相比较,转染siRNA-BCYRN1后PC-3、22RV1细胞Bcl-2、p-Akt表达显著减少(P<0.05),Bax表达显著增高(P<0.05),而Akt表达无明显变化(P>0.05)。结论BCYRN1在前列腺癌组织和细胞中高表达,沉默BCYRN1可抑制前列腺癌细胞增殖,并促进细胞凋亡,其机制可能与调控Akt信号通路有关。     

Antisense oligonucleotides targeted to the human alpha folate receptor inhibit breast cancer cell growth and sensitize the cells to doxorubicin treatment

Folates are essential for cell survival and are required for numerous biochemical processes. The human alpha isoform folate receptor (alphahFR) has a very high affinity for folic acid and is considered an essential component in the cellular accumulation of folates and folate analogues used in chemotherapy. The expression of alphahFR is not detected inmost normal tissues. In contrast, high levels of the expression of alphahFR have been reported in a variety of cancer cells. The significance of alphahFR overexpression in malignant tissues has not been elucidated, but it is possible that it promotes cell proliferation not only by mediating folate uptake but also by generating other regulatory signals. The purpose of the present study was to evaluate alphahFR as a potential target for the treatment of breast cancer. Initial studies were done in nasopharyngeal carcinoma (KB) cells, which express high levels of alphahFR. In KB cells, antisense oligodeoxyribonucleotides (ODN) complementary to the alphahFR gene sequences were found to reduce newly synthesized alphahFR protein up to 60%. To examine the effect of alphahFR antisense ODNs in a panel of cultured human breast cancer cell lines, we used a tumor cell-targeted, transferrin-liposome-mediated delivery system. The data show that alphahFR antisense ODNs induced a dose-dependent decrease in cell survival. Finally, we determined that alphahFR antisense ODNs sensitized MDA-MB-435 breast cancer cells by 5-fold to treatment with doxorubicin. The data support the application of alphahFR antisense ODNs as a potential anticancer agent in combination with doxorubicin.     

尿激酶受体基因反义RNA转移体系的建立及其在白血病研究中的应用

尿激酶受体 (uPAR)表达与肿瘤 /白血病细胞的侵袭与转移能力明显相关。为探讨逆转录病毒载体介导的uPAR基因反义RNA转移体系在抑制白血病细胞表达uPAR中的价值 ,构建了表达反义uPAR基因的逆转录病毒载体LaCD87SN ,用脂质体转染 交互感染策略建立uPAR基因反义RNA转移体系 ,并以双嗜型aCD87病毒转导U937白血病细胞 ;用PCR分析反义uPAR基因的整合和表达 ;用流式细胞术和明胶酶谱分别检测白血病细胞CD87表达和基质金属蛋白酶 (MMP)活性。结果显示 :通过转染 交互感染获得上清中病毒滴度为 6 .3× 10 5cfu/ml的双嗜型病毒产生细胞Am12 /aCD87;aCD87病毒感染的U937/aCD87细胞内存在aCD87原病毒的整合 ,并高水平表达uPAR基因反义RNA。此外 ,与载体对照的U937/NeoR细胞相比 ,U937/aCD87细胞表面CD87分子表达并无明显降低 ,但其分泌MMP 9的能力显著下降。结论 :逆转录病毒载体介导的反义RNA转移不能有效地下调白血病细胞表面uPAR表达 ,但可能干扰CD87分子与MMP的相互作用。     

Adenovirus-mediated transfer of siRNA against survivin induced apoptosis and attenuated tumor cell growth in vitro and in vivo.

Gene targeting using short interfering RNA (siRNA) has become a common strategy to explore gene function because of its prominent efficacy and specificity. For the application of siRNA technology to gene therapy, however, still more efficient transduction of siRNA into target cells is needed. In this study, we developed an adenoviral vector harboring a tandem-type siRNA expression unit, in which sense and antisense strands composing the siRNA duplex were separately transcribed by two human U6 promoters. Targeting survivin, an antiapoptotic molecule widely overexpressed in malignancies but not detected in terminally differentiated adult tissues, this type of adenoviral vector (Adv-siSurv) successfully exerted a gene knockdown effect and induced apoptosis in HeLa, U251, and MCF-7 cells. These cancer cells, once infected with Adv-siSurv, displayed remarkably attenuated growth potential, both in vitro and in vivo. Moreover, intratumoral injection of Adv-siSurv significantly suppressed tumor growth in a xenograft model using U251 glioma cells. This novel modality may be a promising tool for cancer therapy.     

Long noncoding RNA LINC01296 plays an oncogenic role in colorectal cancer by suppressing p15 expression

ObjectiveTo examine the role of the long noncoding RNA LINC01296 in colorectal carcinoma (CRC) and to explore the underlying mechanism.MethodsWe detected LINC01296 expression levels in a cohort of 51 paired CRC and normal tissues. We also assessed the effects of LINC01296 on cell proliferation and apoptosis in CRC cells in vitro, and measured its effect on tumor growth in an in vivo mouse model. We identified the potential downstream targets of LINC01296 and assessed its regulatory effects.ResultsExpression levels of LINC01296 were elevated in 37/51 CRC tissues compared with the corresponding normal tissues and were significantly associated with tumor stage, lymph node metastasis, and distant metastasis. Knockdown of LINC01296 using antisense oligonucleotides inhibited cell proliferation and promoted apoptosis of colon cancer cells in vitro and inhibited tumor growth in vivo. Knockdown of LINC01296 also significantly increased the gene expression of p15 in colon cancer cells. LINC01296-specific suppression of p15 was validated by the interaction between enhancer of zeste homolog 2 and LINC01296.ConclusionOverexpression of LINC01296 suppressed the expression of p15 leading to CRC carcinogenesis. These findings may provide the basis for novel future CRC-targeted therapies.     

Survivin反义RNA/HSP70双基因表达载体的构建及鉴定

目的：构建Survivin反义RNA/HSP70双基因表达载体,为后期转染肿瘤细胞,抑制肿瘤细胞增殖、诱导肿瘤细胞凋亡以及激发机体有效的特异性抗肿瘤免疫应答提供重要的实验材料。方法：应用RT-PCR从Jurkat细胞中获得Survivin cDNA片段,反向插入pIRES2-DsRed2质粒载体中,经酶切和测序鉴定所构建的Survivin反义RNA表达载体是否成功;应用RT-PCR从HepG2细胞中获得的HSP70 cDNA片段,定向插入到pIRES2-DsRed2质粒载体中;经菌落PCR、酶切和测序鉴定所构建的HSP70表达载体是否正确。结果：经酶切和测序鉴定证明Survivin反义RNA表达载体已成功构建;经菌落PCR、限制性酶切和测序鉴定证明HSP70表达载体已成功构建。结论：本实验已成功构建了Survivin反义RNA/HSP70双基因表达载体,为进一步研究提供了实验基础。