HPV18 E6E7 反义荧光真核表达载体的构建及其在宫颈癌HeLa 细胞中的表达

 目的 构建HPV18型E6E7反义荧光真核表达载体,并观察其对宫颈癌HeLa细胞中HPV18 E6和E7基因表达的影响,探索反义技术用于治疗临床HPV感染及宫颈癌的可能性。方法 以HPV18型全基因质粒为模板,PCR法扩增HPV18型E6E7区716bp片段,利用基因重组技术将目的片段反向插入荧光真核表达载体pEGFP-C1,EcoR I酶切并测序鉴定;采用脂转法将重组质粒pEGFP-HPV18 E6E7as（EGFP-18AS）转染宫颈癌HeLa细胞株,通过RT-PCR及western blot检测细胞中E6、E7 mRNA和蛋白的表达。结果 成功构建HPV18E6E7反义荧光真核表达载体EGFP-18AS,经脂质体转染HeLa细胞,48h后在荧光倒置显微镜下可见明显的绿色荧光,且细胞中E6、E7 mRNA及蛋白表达水平均明显下调。结论 反义荧光真核表达载体可以有效的抑制HPV18E6、E7癌基因的表达,为治疗HPV感染和宫颈癌提供了一种新的方法。     

RNA干涉抑制宫颈癌 CaSki细胞株 HPV16 E6基因的研究

背景与目的：研究表明宫颈癌的发生发展与人乳头瘤病毒(human papilloma virus,HPV)E6、E7癌基因密切相关,于是人们采用核酶或HPV E6、E7反义寡核苷酸抑制其表达来治疗宫颈癌,虽然取得了一定的效果,但仍面临基因抑制效率低、维持时间短、工作量大、耗费多等问题。本研究采用最新的RNA干扰技术干扰宫颈癌CaSki细胞中HPV16 E6转录,以了解其能否特异性抑制HPV16 E6基因及其时效性如何。方法：设计合成针对HPV16 E6的荧光标记siRNA,借脂质体转染宫颈癌CaSki细胞,通过荧光照片计数荧光细胞占所有细胞的比例计算转染效率;测定转染后不同时间点的细胞凋亡率;RT-PCR测定HPV16 E6 mRNA变化,Western blot和流式细胞仪检测转染前后蛋白表达情况。结果：相差显微镜荧光照片显示细胞转染的效率为81％。HPV16 E6 siRNA转染细胞后24h、48h、5天凋亡率分别为7．7％、11．8％和37．4％,转染9天时凋亡率下降至12．6％。RT-PCR扩增结果显示,细胞转染前HPV16 E6 mRNA的量与siRNA阴性对照比较没有显著性差异,但转染后24h、48h、5天和9天分别减少了77％、83％、59％和41％;而作为内对照的β-actin mRNA在转染前后无变化。流式细胞仪定量测定HPV16 E6蛋白,结果显示转染后24h、48h和5天,蛋白表达抑制率分别为79．7％、80．4％和71．3％;9天时抑制率有下降,但仍可达57．4％。此结果与HPV16 E6 Western blot结果相吻合。以Lamin A/C作为内对照,不同的时间点Lamin A/C蛋白表达均无差异。结论：宫颈癌CaSki细胞中确实有RNA干扰现象存在,对外源性的HPV16病毒E6基因的干扰具有基因特异性和高效性。     

人乳头瘤病毒16型E6、E7反义RNA对人宫颈癌SiHa细胞的恶性逆转作用

背景与目的:人乳头瘤病毒16型(human papillomavirus 16,HPV16)的早期基因E6、E7可分别诱导p53的泛素化降解和pRb的高磷酸化失活,与宫颈癌的发生发展关系密切.本研究通过真核表达载体介导HPV16型E6、E7基因反义RNA在SiHa细胞中的表达,探讨反义RNA能否降低E6、E7基因的表达和诱导细胞凋亡.方法:利用pEGFP构建HPV16型E6、E7基因反义RNA的真核表达载体并转染SiHa细胞,利用RT-PCR和Western blot技术检测转染后E6、E7基因的mRNA和蛋白的变化,利用MTT法检测SiHa细胞转染后细胞增殖活性,利用流式细胞仪和激光共聚焦显微镜检测转染后细胞的凋亡情况.结果:转染携带HPV16型E6、E7反义基因的质粒后,SiHa细胞的E6、E7基因的mRNA和蛋白表达均明显下调;MTT结果显示转染后细胞的增殖活性(0.50±0.05)与转染空载体细胞(1.01±0.06)和未转染细胞(1.28±0.06)比较明显降低(P＜0.05);流式细胞仪检测结果显示转染后细胞凋亡率(59.3±11.3)%与转染空载体细胞(9.4±1.8)%和未转染细胞(2.1±0.4)%比较有显著性差异(P＜0.05).激光共聚焦显微镜结果示转染后细胞凋亡明显增多.结论:HPV16型E6、E7基因反义RNA可降低宫颈癌细胞中E6、E7癌基因的表达,诱导宫颈癌细胞凋亡.     

宫颈癌细胞系中HPV16 E6、E7及E6/E7基因对STK31基因甲基化状态及表达的影响

背景与目的：丝氨酸/苏氨酸蛋白激酶31(serine/threonine kinases 31,STK31)基因在人类多种癌症中扮演重要角色,且STK31基因的表达受其启动子及第一外显子区甲基化状态的影响;病毒感染与肿瘤组织中某些抑癌基因启动子区高甲基化有关。本研究旨在探讨宫颈癌细胞系中HPV16 E6、E7及E6/E7癌基因对STK31基因甲基化状态及表达的影响,以及不同种类甲基转移酶(DNA methyltransferases,DNMTs)基因在STK31基因甲基化中的潜在作用。方法：构建外源性HPV16 E6、E7以及E6/E7基因共表达慢病毒,分别感染人乳头瘤病毒(human papillomavirus,HPV)阴性宫颈癌细胞系HT-3及C33A,获得稳定转染的细胞系;采用亚硫酸氢盐基因组测序法(bisulfite genomic sequencing,BGS)和甲基化特异性PCR (methylation-specific PCR,MSP)检测3种HPV阳性宫颈癌细胞系HeLa、SiHa和CasKi以及HPV阴性宫颈癌细胞系HT-3和C33A转染前后STK31基因的甲基化状态;RT-PCR及蛋白［质］印迹法(Western blot)检测上述宫颈癌细胞系中STK31基因的表达以及DNMT1、DNMT2、DNMT3a、DNMT3b和DNMT3L基因在HPV16转染前后宫颈癌细胞系及HPV阳性、HPV阴性宫颈癌组织中的表达情况。结果：外源性HPV16 E6、E7以及E6/E7基因可在HPV阴性宫颈癌细胞系中稳定表达。3种HPV阳性细胞系HeLa、SiHa和CasKi中STK31基因呈低甲基化状态,STK31 mRNA及蛋白质表达阳性;2种HPV阴性细胞系HT-3、C33A中STK31基因则表现为高甲基化状态,STK31 mRNA及蛋白质表达缺失;与未感染慢病毒HT-3和C33A细胞系比较,外源性HPV16 E7以及E6/E7表达的HT-3和C33A细胞系STK31基因甲基化程度降低,其mRNA及蛋白质重新表达。DNMT1、DNMT3a和DNMT3b基因在HT-3E6/E7和C33AE6/E7细胞系中mRNA水平分别高于HT-3空载细胞系和C33A空载细胞系,差异有统计学意义(P<0.001)。DNMT1、DNMT3a和DNMT3b基因的mRNA水平在HPV16阳性宫颈癌组织中的表达高于其在HPV阴性宫颈癌组织中的表达,差异有统计学意义(t=5.997,P<0.001;t=6.743,P<0.001;t=7.926,P<0.001)。DNMT2在HT-3E6/E7和C33AE6/E7细胞系中mRNA表达水平分别低于HT-3空载细胞系和C33A空载细胞系,差异有统计学意义(t=7.451,P<0.001;t=2.451,P<0.05);DNMT2基因转录水平在HPV16阳性宫颈癌组织中低于HPV阴性宫颈癌组织(t=9.134,P<0.001)。DNMT3LmRNA表达水平在宫颈癌细胞系转染前后及HPV阴阳性宫颈癌组织中的差异无统计学意义(P>0.05)。结论：HPV感染可导致STK31基因启动子及第1外显子区甲基化状态降低,低甲基化状态促进该基因表达。STK31基因的表达受其启动子及第1外显子区甲基化状态的调控。HPV16 E7、E6/E7基因可能通过影响DNMT2的表达参与调控癌基因STK31基因启动子及第1外显子区甲基化状态。     

人乳头瘤病毒16型E6/E7基因shRNA真核表达载体构建及其对人宫颈癌SiHa细胞增殖及迁移能力的影响

目的 构建针对人乳头瘤病毒16型E6/E7基因的shRNA真核表达载体,获得稳定表达干扰质粒的人宫颈癌SiHa细胞系并探讨其对SiHa细胞增殖及迁移能力的影响。方法 合成3条特异性干扰HPV16 E6/E7基因的shRNA片段并定向插入psilencer 2.1-U6 hygro载体,构建重组质粒psilencer 2.1-U6hygro-shE6/E7并转染入人宫颈癌SiHa细胞, Real- time PCR检测转染后细胞E6/E7 mRNA的表达,选择沉默效应最好的重组质粒并用潮霉素B稳筛,获得稳定表达重组质粒的SiHa细胞,并用real time-PCR和Western blot方法进行鉴定;分别运用CCK-8细胞增殖实验和细胞划痕愈合实验检测细胞的增殖及迁移能力。结果　测序证实针对HPV16 E6/E7的shRNA真核表达载体psilencer 2.1-U6 hygro-shE6/E7构建正确;转染psilencer 2.1-U6 hygro-shE6/E7的SiHa细胞HPV16 E6/E7表达明显受抑,同时其增殖及迁移能力也明显受抑制。结论 psilencer 2.1-U6 hygro-shE6/E7真核表达载体的成功构建并获得稳定沉默表达HPV16 E6/E7的人宫颈癌SiHa细胞系,证实沉默表达HPV16 E6/E7的SiHa细胞增殖及迁移能力会明显受到抑制,这为进一步研究HPV 16 E6/E7基因在宫颈癌发生发展过程中的功能奠定了实验基础。     

microRNA干扰HPV16 E6基因对宫颈癌细胞顺铂敏感性影响的实验研究北大核心CSCD

背景与目的:宫颈癌是常见的妇科恶性肿瘤,其中80%的宫颈癌可以检测到HPV16基因。本研究观察HPV16 E6基因miRNA干扰对宫颈癌CaSki细胞顺铂敏感性的影响。方法:利用分子生物学技术,将本实验室构建的针对HPV16 E6基因的miRNA表达载体pcDNA 6.2-GW/EmGFPmiR,分别转染至CaSki细胞和C-33A细胞内。倒置荧光显微镜观察转染效率,RT-PCR测定HPV16 E6 mRNA变化,蛋白质印迹法(Western blot)检测转染前后E6蛋白表达,MTT法检测转染前后对宫颈癌细胞顺铂敏感性的影响。结果:经杀稻瘟菌素(blasticidin S HCl)选择培养液筛选2周后,将获得的稳定转染细胞分别命名为CaSki-M3和CaSki-N、C-33A-M3和C-33A-N。RT-PCR显示,CaSki-M3细胞内的E6 mRNA转录水平比未转染组降低了99%,E6蛋白的表达抑制率为87.5%。用0.005、0.05、0.5、5、50和500μg/mL的顺铂处理未转染CaSki和C-33A以及转染后CaSki-M3、CaSki-N、C-33A-M3和C-33A-N细胞,CaSki-M3细胞对顺铂的敏感性显著升高(P<0.01)。结论:HPV16 E6 miRNA有效下调HPV16 E6mRNA水平,抑制HPV16 E6蛋白的表达,可明显提高CaSki细胞对顺铂的敏感程度。     

HPV16型E6、E7变异与宫颈癌发生发展的研究进展

宫颈癌是全球15 ～44岁女性中第二常见的恶性肿瘤,每年的死亡人数约为265 653人,在中国,宫颈癌的发生率及死亡率仍较高.高危型人乳头状瘤病毒(HPV)持续感染是宫颈癌前病变及宫颈癌发生的必要条件,HPV16是最常见的高危人乳头瘤病毒.HPV16编码的E6和E7蛋白在HPV相关的肿瘤中起关键作用.近年来的研究揭示了HPV16 E6、E7基因的变异引起氨基酸变化可影响E6、E7蛋白与p53、pRb 的结合,进而与宿主细胞恶性转化相关.本文将对近年来HPV16 E6、E7变异在宫颈癌发生发展中的作用作一综述.     

小干扰RNA抑制宫颈癌Hela细胞株HPV18 E6、E7基因的表达

目的:以人乳头瘤病毒(human papillomavirus,HPV)18型E6基因为靶点,研究小干扰RNA(small interference RNA,siRNA)对宫颈癌Hela细胞株HPV18基因组中恶性转化基因E6、E7的抑制作用及对细胞内P53蛋白表达的影响。方法:实验分细胞培养液阴性对照组(阴性对照组),无关序列siRNA对照组(无关序列对照组)及转染HPV18 E6-siRNA实验组(siRNA实验组)。设计并合成HPV18 E6-siRNA及无关序列siRNA,转染Hela细胞后,RT-PCR检测转染后48、120 h细胞内HPV18E6、E7mRNA的变化,Western blotting检测转染后48 h细胞内HPV18 E7和P53蛋白的变化。结果:siRNA转染Hela细胞的效率约为85%。siRNA转染后48 h,实验组细胞内HPV18E6、E7mRNA及E7蛋白含量降低,其含量分别为阴性对照组的33.33%、36.78%及33.84%;实验组细胞内P53蛋白含量增加,其含量为阴性对照组的2.194倍。siRNA转染后120 h,实验组细胞HPV18E6、E7mRNA含量恢复为阴性对照组的90.91%、101.60%。结论:HPV18 E6-siRNA体外能明显抑制宫颈癌Hela细胞HPV18E6、E7基因的表达,增加细胞内肿瘤抑制因子P53蛋白的水平。     

RNA干涉宫颈癌细胞抑制HPV16 E6基因表达对FHIT基因表达的影响

目的:研究HPV16 E6基因被RNA干涉抑制后FHIT基因表达的变化,探讨两者在宫颈癌组织中的相关性。方法:合成针对HPV16 E6基因的特异性si RNA,脂质体介导转染宫颈癌CaSki细胞,RT-PCR测定转染前后HPV16E6、FHIT基因mRNA表达;Western blot和流式细胞仪检测转染前后HPV16E6、FHIT蛋白表达情况。结果:将HPV16 E6 si RNA转染CaSki细胞后48h,HPV16E6mRNA表达水平较转染前降低了80.3%,P<0.01;FHIT mRNA的表达水平较转染前升高了41.7%,P<0.01。转染前后HPV16E6蛋白表达水平分别为26.7±3.3和8.2±1.1,t=14.224,P=0.005;FHIT蛋白表达水平分别为73.5±5.6和109.9±5.1,t=22.018,P=0.002。结论:抑制HPV16 E6基因的表达可使宫颈癌组织中FHIT基因的表达增加。     

靶向HPV18E6基因siRNA对HeLa细胞p21、VEGF、Bax 和Bcl-2基因的影响

 目的 探讨针对人乳头瘤病毒18型E6基因的特异性小干扰RNA（siRNA）对宫颈癌HeLa细胞p21、VEGF、Bax和Bcl-2基因的影响。 方法 采用脂质体法将特异性siRNA瞬时转染HeLa细胞,半定量RT-PCR检测siRNA转染后HeLa细胞中p21、血管内皮生长因子（VEGF）、Bax和Bcl-2 mRNA的变化,免疫组化检测HeLa细胞中p21和VEGF蛋白的变化。 结果 RT PCR检测结果显示转染后24、48、 72h p21和Bax mRNA的表达与转染前比较均有升高。转染后24、48、72h VEGF和Bcl-2 mRNA的表达与转染前比较均有降低。免疫组化检测结果显示转染后48、72h p21蛋白的表达与转染前比较均有升高。转染后48、72h VEGF蛋白的表达与转染前比较均有降低。 结论 靶向HPV18 E6基因的siRNA可有效干扰宫颈癌HeLa细胞中p21、VEGF、 Bax和Bcl-2基因的表达,从而抑制细胞增殖。     

Mapping of linear epitopes of human papillomavirus type 16: the E1, E2, E4, E5, E6 and E7 open reading frames.

Certain types of human papillomavirus (HPV), especially HPV type 16, are associated with proliferative lesions of the cervix uteri that can progress to malignancy. In order to map the linear epitopes of the HPV-encoded proteins, we have synthesized the predicted amino acid sequences of the open reading frames (ORFs) in the early region of HPV 16, as a set of 94 synthetic 20-residue peptides overlapping each other with 5 amino acids. The peptides were tested for reactivity with IgA, IgG and IgM antibodies in the sera of 30 patients with HPV 16-carrying cervical neoplasia. The EI ORF had only low immunoreactivity, but several relatively minor epitopes were identified in the carboxyterminal part. The E2 ORF was found to contain several epitopes that were highly immunoreactive with a majority (up to 87%) of the cervical cancer patients' sera. The E4 ORF had one major, regularly IgA- and IgG-reactive epitope, whereas the E5 and E6 ORFs had only a few minor epitopes. The E7 ORF had several epitopes that were highly immunoreactive, but only with a minority of patients' sera. The 10 most immunoreactive peptides were also analyzed for immunoreactivity with 60 control sera, of which 22 were derived from patients with parotid gland tumors and 38 were derived from healthy volunteers. Most of the peptides were also immunoreactive with the control sera. However, the IgA antibodies, and to some extent the IgG antibodies, were found at much lower levels among the controls.     

Human papillomavirus E6-induced degradation of E6TP1 is mediated by E6AP ubiquitin ligase

High-risk human papilloma viruses are known to be associated with cervical cancers. We have reported previously that the high-risk human papillomavirus (HPV) E6 oncoprotein interacts with E6TP1, a novel Rap GTPase-activating protein (RapGAP). Similar to p53 tumor suppressor protein, the high-risk HPV E6 oncoproteins target E6TP1 for degradation. The HPV16 E6-induced degradation of E6TP1 strongly correlates with its ability to immortalize human mammary epithelial cells. In this study, we used treatment with a proteasome inhibitor MG132, analysis in CHO-ts20 cells with a thermolabile ubiquitin-activating enzyme, and direct detection of ubiquitin-modified E6TP1 to demonstrate that E6TP1 is targeted for degradation by the ubiquitin-proteasome pathway both in the presence and in the absence of E6. Using deletion mutants of E6TP1, we mapped the region required and sufficient for E6 binding to COOH-terminal 40 amino acid residues and showed this region to be necessary for E6-dependent degradation of E6TP1. Furthermore, the E6-binding region of E6TP1 complexes with E6AP via E6. Importantly, the purified E6AP enhanced the ubiquitination and degradation of E6TP1 in the presence of E6 in vitro. Additionally, the expression of a dominant-negative E6AP mutant (C833A) in cells inhibited the E6-induced degradation of E6TP1. These findings demonstrate that the E6-induced decrease in the levels of E6TP1 protein involves the E6AP-mediated ubiquitination followed by proteasome-dependent degradation.     

The role of human papillomavirus oncoproteins E6 and E7 in apoptosis

The oncogenic potential of 'high risk' human papillomaviruses can be mainly attributed to two small proteins called E6 and E7. Even these oncoproteins have a low molecular size, they are highly promiscuous and are capable to interact with a whole variety of host cellular regulator proteins to elicit cellular immortalization and ultimately complete malignant transformation. To avoid reiterations in summarizing the biochemical and molecular biological properties of E6/E7 in terms of their influence on cell cycle control, the present review is mainly an attempt to describe some regulatory principles by which human papillomavirus (HPV) oncoproteins can interfere with apoptosis in order to escape immunological surveillance during progression to cervical cancer. The models derived from these basic cellular and molecular studies are relevant to our understanding of HPV-induced carcinogenesis. Conversely, experimental procedures aimed at relieving apoptosis resistance, can facilitate the eradication of immunologically suspicious cells and may prevent the accumulation of cervical intraepithelial cell abnormalities in future prophylactic or therapeutic approaches.     

RNA干扰在宫颈癌HPV16E6/E7中的研究进展

RNA干扰(RNAi)是一种有效的基因沉默过程,宫颈癌的重要基因型HPV16的关键致癌基因是E6和E7,目前RNAi在HPV16 E6/E7中的基因沉默作用已取得一些突破性进展.在体外研究方面,正在进一步确定稳定干扰目的 基因的载体形式和筛选更好的干扰序列,在体内研究方面,已建立相应的动物模型,为RNAi的临床研究打下...     

E1/E2 of Hepatitis C Virus Genotype4 and Apoptosis

Several studies have addressed the possible role of hepatitis C virus genotype4 (HCV GT4) in apoptosis. However, this still not fully understood. In the current study a reconstructed clone of E1/E2 polyprotein region of the HCV GT4 was transfected into the Huh7 cell line and a human apoptotic PCR array of 84 genes was used to investigate its possible significance for apoptosis. Out of the 84 genes, only 35 showed significant differential expression, 12 genes being upregulated and 23 downregulated. The highestup regulated genes were APAF1 (apoptotic peptidaseactivating factor 1), BID (BH3 interacting domain death agonist) and BCL 10 (Bcell CLL/ lymphoma protein 10) with fold regulation of 33.2, 30.1 and 18.9, respectively. The most downregulated were FAS (TNF receptor super family), TNFRSF10B (tumor necrosis factor receptor superfamily member 10b) and FADD (FASassociated death domain) with fold regulation of 30.2, 27.7 and 14.9, respectively. These results suggest that the E1/E2 proteins may be involved in HCVinduced pathogenesis by modulating apoptosis through the induction of the intrinsic apoptosis pathway and disruption of the BCL2 gene family.     

Critical role for D-type cyclins in cellular transformation induced by E6/E7 of human papillomavirus type 16 and E6/E7/ErbB-2 cooperation

Recently, we reported that E6/E7 of human papillomavirus (HPV) type 16 cooperates with the ErbB-2 receptor to induce cellular transformation of human normal oral epithelial (NOE) and mouse normal embryonic fibroblast (NEF) cells. Furthermore, we demonstrated that cyclin D1 is essential for this transformation induced by E6/E7 and E6/E7/ErbB-2 cooperation using cyclin D1 antisense and knockout (D1(-/-)) cells. To determine the role of all D-type cyclins (D1, D2 and D3) in E6/E7/ErbB-2 cooperation, we examined the effects of E6/E7, ErbB-2 alone and E6/E7/ErbB-2 together in NEF, NEF-D1(-/-), NEF-D2(-/-) and NEF-D3(-/-) cells. We confirm that NEF-E6/E7 and NEF-E6/E7/ErbB-2, but not NEF-ErbB-2 cells, induce colony formation in soft agar and tumor formation in nude mice. We report that E6/E7, ErbB-2 and E6/E7/ErbB-2 together all fail to induce neoplastic transformation of D1(-/-) and D2(-/-) cells in vitro and in vivo. In contrast, E6/E7/ErbB-2 together but neither E6/E7 nor ErbB-2 alone provoke cellular transformation of D3(-/-) cells. Nevertheless, D3(-/-)E6/E7/ErbB-2 cells resulted in up to a 60 and 50% decrease in colony and tumor formation in soft agar and nude mice, respectively, compared with NEF-E6/E7/ErbB-2 cells. Furthermore, using cyclin D2 small interfering RNA we inhibited tumor and colony formation of the human NOE-E6/E7-ErbB-2-transformed cell line; in contrast, cyclin D3 small interfering RNA repressed approximately 50% of colony and 40% of tumor formation of E6/E7/ErbB-2 cooperation in this cell line. These data suggest that cyclins D1, D2 and D3 (to a lesser extent) are important downstream mediators of the cellular transformation induced by E6/E7 and E6/E7/ErbB-2 cooperation in normal cells. Our data imply that anti-D-type cyclin therapies are important in the treatment of human cancers expressing high-risk HPV or HPV/ErbB-2.     

Enhanced specificity of HPV16 E6E7 siRNA by RNA-DNA chimera modification

Although efforts have been made to develop new drugs for infectious and neoplastic diseases utilizing synthetic small interfering RNA(siRNAs), those intrinsically have undesirable effects, including silencing of unintended genes (off-target effect) and nonspecific cytotoxicity. Off-target effects can be avoided by DNA substitution in the guide strand (GS) seed region of nucleotide positions 1-8 and its complementary part of the passenger strand plus the 3' overhang, which is designated as a double-strand RNA-DNA chimera (dsRDC). In this study, we found that the specificity of potent siRNAs targeting human papillomavirus 16 (HPV16) E6 and E7 oncogenes, which we previously reported, could be enhanced by short dsRDC modification (first six nucleotides from the 5' end of the GS and its complementary nucleotides of the passenger strand). Such dsRDC modification reduced nonspecific cytotoxicity in two of three siRNAs (497 and 752), although not in the other (573), which correlated with their off-target effects. In addition, silencing activity was marginally impaired in two dsRDCs (497 and 573) and moderately in one (752). Finally, dsRDC-497 induced E6E7-specific growth suppression of cervical cancer cells as well as E6E7-immortalized human keratinocytes. Our results show that dsRDC modification enhances the specificity of E6E7 siRNA, which is required for use in in vivo settings.     

HPV16E6、E7治疗性DNA疫苗强化及安全策略

HPV16治疗性DNA疫苗因具有制备简单、稳定、持续时间长、纯度高、可大规模制备等优点而受到人们的关注,但其安全性和免疫效率低是其致命弱点.许多方案已用于提高疫苗的安全性和免疫原性,如与结核分枝杆菌热休克蛋白70(HSP70)基因融合、与蛋白转运载体基因融合、突变某些功能基因、构建"自杀性"DNA疫苗等.现就其安全和强化策略进行综述,为研制安全高效DNA疫苗奠定基础.