DNA vaccine coding for the rhesus prostate specific antigen delivered by intradermal electroporation in patients with relapsed prostate cancer

We tested safety, clinical efficacy and immunogenicity of a DNA vaccine coding for rhesus prostate specific antigen (PSA) delivered by intradermal injection and skin electroporation. Fifteen patients with biochemical relapse of prostate cancer without macroscopic disease participated in this phase I study. Patients were started on a 1 month course of androgen deprivation therapy (ADT) prior to treatment. Vaccine doses ranged from 50 to 1600 μg. Study subjects received five vaccinations at four week intervals. All patients have had at least one year of follow-up. No systemic toxicity was observed. Discomfort from electroporation did not require analgesia or topical anesthetic. No clinically significant changes in PSA kinetics were observed as all patients required antiandrogen therapy shortly after completion of the 5 months of vaccination due to rising PSA. Immunogenicity, as measured by T-cell reactivity to the modified PSA peptide and to a mix of overlapping PSA peptides representing the full length protein, was observed in some patients. All but one patient had pre-study PSA specific T-cell reactivity. ADT alone resulted in increases in T-cell reactivity in most patients. Intradermal vaccination with skin electroporation is easily performed with only minor discomfort for the patient. Patients with biochemical relapse of prostate cancer are a good model for testing immune therapies.     

基因治疗对下颌骨牵引过程中碱性成纤维细胞生长因子表达的影响

目的 探讨电穿孔介导的基因治疗对兔下颌骨牵引成骨过程中碱性成纤维细胞生长因子(basic fibroblast growth factor,bFGF)表达的影响.方法 新西兰大白兔双侧下颌骨截骨,术后3d开始以0.8 mm/d速度行下颌骨牵引,连续牵引7d,将实验动物分为:A、B、C、D、E5组.分别在牵引区注射2μg重组质粒pIRES-hVEGF165-hBMP2、pIRES-hBMP2、pIRES-hVEGF165、空质粒pIRES及生理盐水.各组实验动物均施加电穿孔刺激.各组分别于固定期第7、14、28天处死动物取材行免疫组织化学检查bFGF的表达,并利用病理图像分析系统进行分析.结果 bFGF在肉芽中的成纤维细胞、单核巨噬细胞、多核巨噬细胞、间质细胞、成骨细胞和骨细胞中表达:1周时以C组表达较强,2、4周时以A、B、C组表达仍较强,A、B、C组与D、E组相比差异有统计学意义(P＜0.01).结论 电穿孔介导的基因治疗能使bFGF在牵引区的表达增强和表达时限延长,发挥其生理作用,促进细胞的分裂增殖与分化及牵引区细胞基质的形成和新骨生成.这可能是基因治疗促进牵引区新骨生成的机制之一.     

鸡胚发育过程敲减神经型钙粘蛋白表达对视顶盖神经元迁移及神经丝蛋白的影响

目的 阐明鸡胚发育过程神经型钙黏蛋白（N-cadherin）在中枢神经系统中的作用及其对神经丝蛋白(NF)表达的影响。 方法 鸡胚正常培养到第3天（E3）,采用鸡胚带壳开窗培养方法,取出3～4ml蛋清,开窗培养至E5,将N-cadherin干扰载体pGPU6-GFP-neo-N-cadherin-shRNA通过活体电转基因技术导入视顶盖,电转后继续培养到E12,每组收集3个胚胎,取材,固定,包埋,切片后进行荧光免疫组织化学分析相关蛋白的表达。结果 鸡胚发育过程,敲减N-cadherin表达影响神经元迁移,被敲减的细胞主要停留在室管膜区,在N-cadherin受到抑制表达的区域,NF的表达也受到抑制,其表达明显减弱。 结论 N-cadherin的抑制表达可导致神经元的迁移发生紊乱,影响NF的表达。     

Electric Fields in Tumors Exposed to External Voltage Sources: Implication for Electric Field-Mediated Drug and Gene Delivery

The intratumoral field, which determines the efficiency of electric field-mediated drug and gene delivery, can differ significantly from the applied field. Therefore, we investigated the distribution of the electric field in mouse tumors and tissue phantoms exposed to a large range of electric stimuli, and quantified the resistances of tumor, skin, and electrode-tissue interface. The samples used in the study included 4T1 and B16.F10 tumors, mouse skin, and tissue phantoms constructed with 1% agarose gel with or without 4T1 cells. When pulsed electric fields were applied to samples using a pair of parallel-plate electrodes, we determined the electric field and resistances in each sample as well as the resistance at the electrode-tissue interface. The electric fields in the center region of tissue phantoms and tumor slices ex vivo were macroscopically uniform and unidirectional between two parallel-plate electrodes. The field strengths in tumor tissues were significantly lower than the applied field under both ex vivo and in vivo conditions. During in vivo stimulation, the ratio of intratumoral versus applied fields was approximately either 20% or 55%, depending on the applied field. Meanwhile, the total resistance of skin and electrode-tissue interface was decreased by approximately 70% and the electric resistance at the center of both tumor models was minimally changed when the applied field was increased from 50 to 400 V/cm. These results may be useful for improving electric field-mediated drug and gene delivery in solid tumors.     

Numerical Determination of Transmembrane Voltage Induced on Irregularly Shaped Cells

The paper presents an approach that reduces several difficulties related to the determination of induced transmembrane voltage (ITV) on irregularly shaped cells. We first describe a method for constructing realistic models of irregularly shaped cells based on microscopic imaging. This provides a possibility to determine the ITV on the same cells on which an experiment is carried out, and can be of considerable importance in understanding and interpretation of the data. We also show how the finite-thickness, nonzero-conductivity membrane can be replaced by a boundary condition in which a specific surface conductivity is assigned to the interface between the cell interior (the cytoplasm) and the exterior. We verify the results obtained using this method by a comparison with the analytical solution for an isolated spherical cell and a tilted oblate spheroidal cell, obtaining a very good agreement in both cases. In addition, we compare the ITV computed for a model of two irregularly shaped CHO cells with the ITV measured on the same two cells by means of a potentiometric fluorescent dye, and also with the ITV computed for a simplified model of these two cells.     

成纤维细胞生长因子信号调控早期鸡胚胎神经嵴细胞的迁移

目的 利用Sprouty2基因阻断成纤维细胞生长因子（FGF）信号,探讨FGF在早期鸡胚胎发育过程中对神经嵴细胞迁移的影响及其机制。方法 通过体内培养的方法孵育鸡胚至HH9期,通过显微注射的方法将Sprouty2-绿色荧光蛋白（GFP）质粒注射入神经管腔内。实验侧使用电穿孔转染的方法转染胚胎半侧神经管,另一侧正常神经管设为对照侧。采用神经嵴细胞特异标记物HNK1免疫荧光的方法检测Sprouty2基因阻断FGF信号后是否影响胚胎头部和躯干部神经嵴细胞的迁移过程。随后,进一步通过检测神经细胞钙黏分子N-Cadherin的表达来观察细胞之间黏附作用的改变。结果 HNK1免疫荧光检测结果显示,Sprouty2转染侧即阻断FGF信号通路后,HNK1在早期鸡胚胎的头部和躯干部的表达量均比对照侧的表达量增多;而神经细胞钙黏分子N-Cadherin检测结果表明,Sprouty2转染侧和正常对照侧N Cadherin在头部和躯干部神经管上表达量的差异均无显著性。结论 Sprouty2基因阻断FGF信号后,促进了早期鸡胚胎神经嵴细胞的迁移,但是FGF信号对此过程的影响可能不是由神经钙黏分子N-Cadherin介导的。     

A 3D in vitro spheroid model as a way to study the mechanisms of electroporation

Electropermeabilization is a physical method to deliver molecules into cells and tissues. Clinical applications have been successfully developed for antitumoral drug delivery and clinical trials for gene electrotransfer are currently underway. However, little is known about the mechanisms involved in this transfer. The main difficulties stem from the lack of single cell models which reliably replicate the complex in vivo environment. In order to increase our understanding of the DNA electrotransfer process, we exploited multicellular tumor spheroids as an ex vivo model of tumor. We used confocal microscopy to visualize the repartition of permeabilized cells in spheroids subjected to electric pulses. Our results reveal that even if cells can be efficiently permeabilized with electric fields, including those cells present inside the spheroids, gene expression is by contrast limited to the external layers of cells. Taken together, these results, in agreement with the ones obtained in tumors, indicate that the spheroid model is more relevant to an in vivo situation than cells cultured as monolayers. They validate the spheroid model as a way to study electro-mediated gene delivery processes.     

构建睫状神经营养因子绿色荧光蛋白融合表达载体电穿孔转染雪旺细胞的研究

目的 构建睫状神经营养因子-绿色荧光蛋白(CNTF-GFP)融合表达质粒,以电穿孔法辅助转染培养的雪旺细胞,为优化细胞移植、促进视神经再生提供效果更好且便于观察的方法.方法 实验研究.构建重组质粒pcDNA3.1/CNTF-GFP;经测序鉴定后,电穿孔法辅助转染培养的雪旺细胞;荧光显微镜下动态观察转染效果,流式细胞计数;转染24 h后,用RT-PCR及免疫组化法检测基因转染及蛋白表达情况.结果 重组质粒经测序鉴定无误;在3 h即可见部分荧光,12 h逐渐增多,24～72 h到达高峰,持续至7 d仍有表达;流式细胞计数得转染率为44.93%±12.92%,转染24 h后,RT-PCR示目的 基因有较高转录,免疫组化示有CNTF蛋白的高表达,并与GFP蛋白表达部位完全重合.结论 成功构建了CNTF-GFP融合表达质粒;电穿孔法转染雪旺细胞后,表达良好,为制备转基因的种子细胞从而促进视神经再生的研究奠定了基础.     

Cellular and humoral responses to an HIV DNA prime by electroporation boosted with recombinant vesicular stomatitis virus expressing HIV subtype C Env in a randomized controlled clinical trial

BackgroundHIV subtypes B and C together account for around 60% of HIV-1 cases worldwide. We evaluated the safety and immunogenicity of a subtype B DNA vaccine prime followed by a subtype C viral vector boost.MethodsFourteen healthy adults received DNA plasmid encoding HIV-1 subtype B nef/tat/vif and env (n = 11) or placebo (n = 3) intramuscularly (IM) via electroporation (EP) at 0, 1, and 3 months, followed by IM injection of recombinant vesicular stomatitis virus encoding subtype C Env or placebo at 6 and 9 months. Participants were assessed for safety, tolerability of EP, and Env-specific T-cell and antibody responses.ResultsEP was generally well tolerated, although some device-related adverse events did occur, and vaccine reactogenicity was mild to moderate. The vaccine stimulated Env-specific CD4 + T-cell responses in greater than 80% of recipients, and CD8 + T-cell responses in 30%. Subtype C Env-specific IgG binding antibodies (bAb) were elicited in all vaccine recipients, and antibody-dependent cell-mediated cytotoxicity (ADCC) responses to vaccine-matched subtype C targets in 80%. Negligible V1/V2 and neutralizing antibody (nAb) responses were detected.ConclusionsThis prime/boost regimen was safe and tolerable, with some device-related events, and immunogenic. Although immunogenicity missed targets for an HIV vaccine, the DNA/rVSV platform may be useful for other applications.Trial registration.Clinicaltrials.gov: NCT02654080.