特异性启动子LEP503介导的自杀基因系统对晶状体上皮细胞增殖的抑制作用

目的构建晶状体上皮细胞(lens epithelial cells,LEC)特异性启动子LEP503(lens epithelium gene product503)调控的Lenti-LEP503-HSV-tk-EGFP载体,观察慢病毒介导的单纯疱疹病毒胸苷激酶/丙环鸟苷系统(herps simplex virus thymidine kinase/ganciclov-ir,HSV-tk/GCV)自杀基因系统对人晶状体上皮细胞(HLEC)增殖的靶向性抑制作用。方法用RT-PCR方法从HLEC基因组中克隆LEP503启动子序列,构建单纯LEP503启动子调控HSV-tk基因表达的慢病毒载体Lenti-LEP503-HSV-tk-EGFP,同时构建广谱启动子巨细胞病毒(cytomegalo virus,CMV)调控的HSV-tk载体Lenti-CMV-HSV-tk-EGFP。将特异性表达载体Lenti-LEP503-HSV-tk-EGFP分别转入HLEC和Hela细胞,用荧光显微镜观察荧光强度,用RT-PCR方法评估相关蛋白的组织特异性表达。将Lenti-LEP503-HSV-tk-EGFP和Lenti-CMV-HSV-tk-EGFP分别转入HLEC,通过荧光显微镜观察EGFP的表达,用流式细胞仪及RT-PCR比较CMV与LEP503启动子介导下游靶基因HSV-tk的表达差异。结果 Lenti-LEP503-HSV-tk-EGFP能在HLEC中特异性表达,但Lenti-LEP503-HSV-tk-EGFP的表达效率明显低于Lenti-CMV-HSV-tk-EGFP。转染Lenti-LEP503-HSV-tk-EGFP的HLEC在20mg·L-1GCV作用48h后EGFP阳性细胞的形态发生明显变化;GCV作用24h后Lenti-LEP503-HSV-tk-EGFP转染HLEC较正常HLEC和Lenti-LEP503-HSV-tk-EGFP转染Hela细胞活性有明显抑制,且随时间的延长抑制效果逐渐增强。结论 LEP503启动子能介导HSV-tk基因在HLEC中特异表达,并介导HSV-tk/GCV自杀基因系统靶向性抑制HLEC增殖,但该启动子表达效率较低,所介导的HSV-tk/GCV系统对HLECs增殖的抑制效率低于CMV启动子。

Vascular damage and anti-angiogenic effects of tumor vessel-targeted adenovirus-mediated herpes simplex virus thymidine kinase gene

AIM： To explore the therapeutic efficacy and mechanism of herpes simplex virus-thymidine kinase （HSV-tk） targeting angiogenesis against hepatocellular carcinoma in vivio and in vitro. METHODS： Recombinant adenovirus containing kinase domain insert with receptor （KDR） or cytomegalovirus （CMV） promoter-controlled HSV-tk gene （AdKDR-tk and AdCMV-tk） was constructed using pAdeasy system. The expression of KDR antigen in human umbilical venous endothelial cells （HUVEC） and HepG2 was detected with histological analysis of cells. The virus was used to infect HUVEC and HepG2. Following administration of ganciclovir （GCV）, the survival rate of gene-transfected HUVEC and HepG2 was evaluated by MTT method. To develop hepatocarcinomas in 32 Balb/C mice with HepG2 cells, the mice were divided into four groups： ganciclovir group （Ⅰ）, Ad group （Ⅱ）, AdCMV-tk group （Ⅲ） and AdKDR-tk group （Ⅳ）. Then selective administration of recombinant adenovirus or Ad via the intratumorial was given to all rats. Ganciclovir （GCV） was given at a dose of 100 mg·kg^-1·d^-1 （ip） started on the following day and lasted 10 d. Microvessel density （MVD） of tumor in all the treated animals were examined by the immunohistochemical methods and tumor burden was evaluated 10 d before and alter the last GCV dose.RESULTS： Immunocytochemical staining indicated the expression of KDR antigen in HUVEC. Under adenovirus infection index of 100, with increasing GCV concentration from 0 up to 50 mg/L, the survival rate of AdKDR-tk- transfected HUVEC and HepG2 decreased from 100% to （28.94 ± 5.67）% and （75.45 ± 2.91）% at proper order, respectively （P 〈 0.01）, while the survival rate of AdCMV- tk-transfected HUVEC and HepG2 declined from 100% to （17.56 ± 2.48）% and （23.15± 5.72）%, respectively （P 〉 0.05）. Compared with group I, there was a decrease of tumor weight by 14.7% in group Ⅲ and by 23.6% in group Ⅳ. And there was a distinct difference between group M and Ⅳ （P 〈 0.05）. The median MVD for all groups was 37.4 ± 8.6, 30.6 ± 7.8, 27.6 ± 7.1, and 10.7 ± 4.1 （microvessels/mm^2） in group Ⅰ, Ⅱ, M and IV, respectively. And there was a marked difference between group M and Ⅱ （P 〈 0.05）, Ⅳ and Ⅱ （P 〈 0.01）, and Ⅳ and M （P 〈 0.01）. CONCLUSION： KDR promoter-HSV-tk gene may effectually restrain the growth of tumor via targeting angiogenesis for hepatocellular carcinoma with treatment of GCV.

Serial imaging of human embryonic stem-cell engraftment and teratoma formation in live mouse models

Two new types of lentiviral vectors expressing a reporter transgene encoding either firefly luciferase （fLuc） for bioluminescence imaging or the HSV1 thymidine kinase （HSV1-TK） for radiopharmaceutical-based imaging were constructed to monitor human embryonic stem cell （hESC） engraftment and proliferation in live mice after trans- plantation. The constitutive expression of either transgene did not alter the properties of hESCs in the culture. We next monitored the formation of teratomas in SCID mice to test （1） whether the gene-modified hESCs maintain their developmental pluripotency, and （2） whether sustained reporter gene expression allows noninvasive, whole-body imaging of hESC derivatives in a live mouse model. We observed teratoma formation from both types of gene-modified cells as well as wild-type hESCs 2-4 months after inoculation. Using an optical imaging system, bioluminescence from the fLuc-transduced hESCs was easily detected in mice bearing teratomas long before palpable tumors could be detected. To develop a noninvasive imaging method more readily translatable to the clinic, we also utilized HSV1-TK and its specific substrate, 1-（2＇-deoxy-2＇-fluoro-β-D-arabinofuranosyl）-5-[^125I]iodouracil（[^125I]FIAU）, as a reporter/ probe pair. After systemic administration, [^125I]FIAU is phosphorylated only by the transgene-encoded HSV1-TK enzyme and retained within transduced （and transplanted） cells, allowing sensitive and quantitative imaging by single-photon emission computed tomography. Noninvasive imaging methods such as these may enable us to monitor the presence and distribution of transplanted human stem cells repetitively within live recipients over a long term through the expression of a reporter gene.

Retrovirus-mediated herpes simplex virus thymidine kinase gene therapy approach for hepatocellular carcinoma

The therapeutic effect of herpes simplex virus thymidine kinase/ganciclovir (HSV-tk/GCV) system on hepatocellular carcinoma was studied in this experiment. The tk-containing retroviral recombinants were used to infect hepatoma cells (BEL-7402) and the cells were treated with ganciclovir (0-1000 microg/ml). The results showed that HSV-tk gene could be efficiently transferred in vitro into hepatoma cells and stably expressed. The growth potential of the tk-containing cells was significantly inhibited by GCV (P

Quantitation of Genital Herpes Virus DNA by Polymerase Chain Reaction and ELISA

Objective: To detect and quantitate genital herpes simplexvirus (HSV) DNA in specimens from 100 patients clinicallydiagnosed with genital herpes. Methods: Polymerase Chain Reaction (PCR) andenzyme-linked immunosorbent assay (ELISA) were used witha standard curve of DNA copies of HSV as quantitativecontrast. Results: Ninety-three cases were confirmed HSV positiveand 7 cases were found to be negative. There were 58 cases ofHSV-2 (62.4%) and 35 cases of HSV-1(37.6%) among the 93positive cases. The number of DNA plasmids ranged from 115to 1.1×10~5 per 250μL among the 93 positive samples (mean=7.1×10~4/250μL). The number of HSV DNA plasmids rangedfrom 136 to 1.1×10~5 copies per 250μL(mean=7.6×10~4) amongthose with HSV-2, and 115 to 9.4×10~4 per 250μL(mean=6.3×10~4) among those with HSV-1. Meanwhile 10μL ofextracted and dissolved DNA randomly taken from 8 each ofHSV-2 and HSV-1 samples were tested. The number of HSV-2DNA plasmids ranged from 35 copies to 2.7×10~4 (Mean=1.8×10~4) and the number of HSV-1 DNA ranged from 29 to2.5×10~4 (Mean=1.6×10~4). In the 7 negative cases, the quantityof HSV plasmids was zero. Conclusion: The sensitivity of ELISA quantitation (93%) isequal to that of Southern blot. The sensitivity of PCR fordiagnosis is 91%, and 88% for PCR typing.

Construction of the recombinant vector carrying herpes simplex virus thymidine kinase and cytokine genes expressed in cell line Tca8113

Objective: To construct expression vector containing fusion genes of herpes simplex virus thymidine kinase(Hsv-tk), Interleukin-2(IL-2) with internal ribosome entry sites(IRES), and to assess their expression in cell line Tca8113. Methods: IL-2 cDNA was obtained by reverse transcription. Hsv-tk, IL-2 and IRES genes were amplified by PCR. The purified amplification products were inserted into pGEM-T-Easy, and transformed into E.coli JM109. The purified recombinant plasmids were identified by restriction endonucleases. The recombinant plasmids were digested and pEGFP-N 3 were linearized, DNA fragments of Hsv-tk, IRES and IL-2 were ligated into linearized pEGFP-N 3, and then transferred into E.coli JM109. The recombinant tk-IL-2 genes were cloned separately and introduced into the expression vector pEGFP-N 3 containing GFP. The recombinant vectors were identified by their restriction sites through PCR. The plasmids pEGFP-TI was also transfected into Tca8113 cells by calcium phosphate method for the expression of fusion proteins. Fusion genes expressing vector PL(TI)SN was generated by the fusion of HSV-tk, IRES and IL-2 with the use of DNA recombination technology. The recombinant retroviruses were transferred into Tca8113 cells by lipofectamine. The positive clones were obtained after G418 selection and named Tca/TI respectively. Results: The pEGFP-TI pasmid was identified respectively by restriction endonucleases, and their fragment sizes were 1 120 bp and 450 bp. The pEGFP-TI pasmid as templates were amplified respectively by PCR, and their PCR products were 1 120 bp and 450 bp. The pEGFP-TI vectors were used to transfect Tca8113 cell, and the cells with fluorescence accounted for 60% of the total amount. Conclusion: pFGFP-tk-IRES-IL-2 expressing vector is easy to assess the expression of tk-IRES-IL-2-GFP fusion protein localization in transfected cells. The successful construction of expressing vector containing fusion genes of Hsv-tk, IRES and IL-2 may be beneficial for gene therapy in cell line Tca8113.

Effects of herpes simplex virus thymidine kinase/acyclovir system on growth of human pulmonary adenocarcinoma A549 cell line in vitro and in vivo

Objective: To observe the effect of anciclovir (ACV) treatment on tumors induced by inoculation of TK gene-transfected human pulmonary adenocarcinoma A549 cells in nude mice. Methods: A recombinant plasmid containing TK gene was constructed and transfected into A549 cells by electroporation. The sensitivity of the transgenic cells (A549-TK) to ACV was examined by MTT assay in vitro and for in vivo observation, inoculation of A549-TK and A-549 cells into nude mice was separately performed to induce tumor growth, the response of which to ACV treatment was observed, and the tumor tissues were pathologically examined. Results: A recombinant plasmid containing TK gene was successfully constructed and transfected into A549 cells. The sensitivity of A549-TK cells to ACV was 43 times higher than that of A549 cells. The tumors induced by A549-TK cells showed no significant increase in size after ACV treatment (P>0. 05) , and light microscopy revealed local tissue necrosis, karyoklasis, and nuclei disappearance. Conclusion: A549-TK cells acquires sensitivity to ACV both in vitro and in vivo, and ACV can inhibit the growth of tumors induced by A549-TK cell inoculation in nude mice.

Non-viral targeted delivery system mediates transfection of thymidine kinase gene of herpes simplex virus into ovarian cancer cells:a comparison between one time and continuous mediation

Objective： To compare the transferring efficiency and killing effects of one time and continuous mediation with GE7, a non-viral targeted delivery system, in transfection of thymidine kinase gene of herpes simplex virus （HSV-tk） into ovarian cancer cells. Methods： GE7 was used to prepare recombinants with β-galactosidase （β-gal） and HSVI-tk; the recombinants were then used to transfect human ovarian cancer line CaOV3 once and continuously. β-gal staining was used to compare the efficiencies of one time and continuous mediation with GE7 system. Ganciclovior （GCV） was introduced into HSVI-tk transfected ovarian cells. Through drawing the cell growth curve and flow cytometry, the killing effects of GCV on once and continuously GE7/HSVI-tk transfected cells were observed. Results： We found that the one time and continuous exogenous gene transfer efficiencies were about 80% and 85%, respectively. When 1 μg/mL GCV was used to treat ovarian cell transfected with HSVI-tk gene, growth inhibiting rates of ovarian cells of one time and continuous transferring were 82% and 90%, respectively; their apoptosis indices were 15 and 30, respectively. Under same GCV concentration, continuous mediation of GE7/pCMV-tk transfection into ovarian cancer cells had more significant inhibitory effect than one time mediation （P 〈 0.05）. Conclusion： Compared with one time mediation, continuous mediation of transfection with GE7 gene delivery system has higher efficiency. Continuous mediation of GE7/HSVI-tk/GCV therapeutic gene system has more powerful killing effect.

Clinical Presentation of Atypical Genital Herpes

Objective: To make a clinical analysis on the basis of 36 cases of atypical genital herpes (GH) patients. Methods: Thirty-six cases of atypical GH were diagnosedclinically, and their case histories, symptoms and signs wererecorded in detail and followed up. Polymerase chain reaction(PCR) was adopted for testing HSV2-DNA with cotton-tippedswabs. Enzyme-linked immuno sorbent assay (ELISA) forserum anti-HSV2-IgM was done to establish a definitivediagnosis. Other diagnoses were excluded at the same time bytesting for related pathogens including fungi, Chlamydia,Mycoplasma, Treponema pallidum, gonococci, Trichomonas,etc. Results: The main clinical manifestations of atypical GHwere: (1) small genital ulcers; (2) inflammation of urethralmeatus; (3) nonspecific genital erythema; (4) papuloid noduleson the glands; (5) nonspecific vaginitis. Twenty-three cases(64%) tested by PCR were HSV2-DNA sera-positive, and 36cases (100%) anti-HSV2-1gM sera-positive by ELISA. Conclusion: atypical HSV is difficult to be dinosed. But the combination of PCR and ELIAS will be helpful to thediagnosis of atypical HSV.