Fas/FasL基因转染联合顺铂对直肠癌细胞杀伤作用的研究

目的探讨Fas/FasL基因转染联合顺铂对直肠癌细胞的杀伤作用。方法构建pcDNA3.1-Fas/FasL真核表达载体,将人Fas/FasL基因通过脂质体导入直肠癌8348细胞中,并利用RT-PCR方法检测直肠癌8348细胞的Fas/FasL基因mRNA表达。用MTT法分析顺铂对转染前后的8348细胞抑制增殖和诱导凋亡的能力。结果Fas/FasL基因转染可明显增强直肠癌8348细胞的Fas/FasL表达。分别加入不同浓度顺铂(1、5、10、20、40μg/ml),Fas转染组8348细胞抑制率分别为47.2%、51.8%、57.2%、65.4%、71.0%;后者细胞抑制率分别为29.6%、33.0%、37.8%、41.4%、47.0%,其差异有显著性意义(t=15.33,P<0.01);FasL转染组8348细胞抑制率分别为11.0%、25.4%、31.2%、37.8%、42.4%;对照组8348细胞抑制率分别为26.1%、34.4%、37.6%、42.9%、53.2%,其差异有显著性意义(t=4.43,P<0.05)。结论转染的Fas/FasL基因可显著上调直肠癌8348细胞的Fas/FasL表达;Fas基因转染联合顺铂对直肠癌细胞有更强的杀伤作用;FasL基因转染可减弱顺铂对8348细胞的细胞毒作用,因此为直肠癌的基因治疗和化疗提供了理论依据。     

Fas基因转染联合顺铂对直肠癌细胞杀伤作用的研究

目的探讨Fas基因转染联合顺铂对直肠癌细胞的杀伤作用。方法采用RT PCR技术从健康人的外周血单核细胞中扩增包含全部阅读框架的Fas全长基因 ,与 pGEM TEasy质粒连接 ,经测序验证。构建 pcDNA3 1 Fas真核表达载体 ,将人Fas基因通过脂质体导入直肠癌 8348细胞中 ,并利用RT PCR方法检测直肠癌 8348细胞的Fas基因mRNA表达。用MTT法分析顺铂对转染前后直肠癌细胞抑制增殖和诱导凋亡的作用。结果Fas基因转染可明显增强直肠癌 8348细胞的Fas表达 ,分别用 1、5、10、2 0、4 0mg/L浓度的顺铂作用 ,转染Fas基因的 8348细胞实验组细胞抑制率分别为 4 7 2 %、5 1 8%、5 7 2 %、6 5 4 %、71 0 % ;未转染Fas基因的 8348细胞对照组细胞抑制率分别为 2 9 6 %、33 0 %、37 8%、4 1 4 %、4 7 0 % ,2组相比 ,差异有显著性意义 (t =15 33,P <0 0 1)。结论转染的Fas基因可显著上调直肠癌 8348细胞的Fas表达 ,促进细胞凋亡 ,Fas基因转染联合顺铂对直肠癌细胞有更强的杀伤作用。     

Fas ligand and TNF-related apoptosis-inducing ligand induction on infiltrating lymphocytes in bladder carcinoma by bacillus Calmette-Guérin treatment

AIM: To determine the molecular mechanisms underlying the efficacy of bacillus Calmette-Guérin (BCG) therapy against superficial carcinoma of the urinary bladder, we evaluated the expression of cytotoxic molecules on tumor-infiltrating lymphocytes before and after therapy. METHODS: Immunofluorescence staining allowed the specific detection of Fas, Fas ligand (FasL), and tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) expression on tumor cells and the respective leukocyte populations in biopsy samples from 6 patients. RESULTS: Significant increases in the infiltration of FasL- and TRAIL-expressing CD4+ T cells and macrophages and FasL-expressing CD8+ T and NK cells were observed after BCG instillation in bladder carcinoma. Moreover, Fas expression was upregulated on tumor cells after BCG instillation. CONCLUSION: The data suggested that the enhanced infiltration of FasL- and/or TRAIL-expressing leukocytes (CD4+ T cells, CD8+ T cells, natural killer cells and macrophages) and the induction of Fas expression on tumor cells may play an important role in the therapeutic effect of BCG instillation.     

Intrasplenic transplantation of allogeneic hepatocytes modified by BCL-2 gene protects rats from acute liver failure

BACKGROUND: Apoptosis of donor hepatocytes may be induced by recipient cytotoxic T lymphocytes (CTLs) during acute rejection, representing a major impediment for these cell transplants. Because the mechanisms of transplanted hepatocyte loss involve Fas-mediated pathways, BCL-2 genetic modification may protect liver cells. In the present study, we further investigated whether BCL-2 transfer into transplanted liver cells rendered them resistant to Fas ligand-induced apoptosis, and protected rats from acute liver failure. MATERIALS AND METHODS: Hepatocytes isolated from Sprague-Dawley rats were infected with an adenovirus vector encoding human BCL-2 gene (AdCMVBCL-2) or a control AdCMVLacZ vector. Forty-eight hours later, cells challenged with recombinant Fas ligand (rhsFasL) were assayed for apoptosis using TUNEL staining and caspase 3 activity. Other cells were transplanted into the spleens of Wistar rats with a 90% hepatectomy 12 hours later. RESULTS: Western blot analysis and RT-PCR confirmed the expression of hBcl-2 in AdCMVhBcl-2-infected hepatocytes. Recombinant FasL produced a dose-dependent increase in TUNEL-positive percentage and caspase-3 activity in uninfected hepatocytes, but did not influence these features in AdCMVhBcl-2-infected cells. On challenge with 90% hepatectomy, the survival of Wistar rats receiving transplantation of AdCMVhBCL-2-infected hepatocytes was significantly prolonged compared with the controls. CONCLUSION: Adenovirus-mediated BCL-2 gene transfer protects transplanted hepatocytes from Fas-mediated cytolysis, thus holding promise for a new avenue of acute liver failure treatment.     

Adenovirus-mediated Bcl-2 gene transfer inhibits apoptosis and promotes survival of allogeneic transplanted hepatocytes

BACKGROUND: Donor hepatocyte apoptosis that is induced by host cytotoxic T lymphocytes (CTLs) limits the application of hepatocyte transplantation. Hepatocytes from Bcl-2 transgenic mice can resist the lethal effect of anti-Fas antibody. However, the anti-apoptotic effect of Bcl-2 expression on allogeneic transplanted hepatocytes remains elusive. This study tested the feasibility of Bcl-2 gene transfer as an approach to inhibit CTL-mediated apoptosis in allogeneic transplanted hepatocytes. METHODS: An adenovirus vector that encoded human Bcl-2 gene (AdCMVhBcl-2) was used to transfect cultured rat hepatocytes, which were then transplanted into allogeneic spleens. DNA fragmentation and caspase-3 activation were examined by terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end-labeling assay and immunohistochemistry for active caspase-3, respectively. Cocultivation of hepatocytes and allogeneic CD8(+) T lymphocytes was performed, and cytotoxicity on hepatocytes was examined by alanine transaminase release. RESULTS: Bcl-2 gene transfer inhibited apoptosis and increased liver-associated enzyme activities in allogeneic transplanted hepatocytes, which were associated with inhibition of caspase-3 activation. Alanine transaminase release in hBcl-2 modified hepatocytes was lower compared with controls, which could not be further decreased by inhibition of Fas ligand and granzyme B. CONCLUSIONS: Adenovirus-mediated Bcl-2 gene transfer blocks CTL-mediated apoptosis in allogeneic hepatocytes by inhibition of caspase-3 activation. Bcl-2 gene transfer could be used to promote survival of transplanted hepatocytes.     

A genetically retargeted adenoviral vector enhances viral transduction in esophageal carcinoma cell lines and primary cultured esophageal resection specimens

OBJECTIVE: To evaluate if an integrin-retargeted adenoviral vector could establish a more efficient and tumor-specific gene transfer in esophageal carcinoma cells. SUMMARY BACKGROUND DATA: Although preclinical data indicated that adenoviral gene therapy could be a promising novel treatment modality for various malignancies, clinical results are often disappointing. An important problem is the decreased tumoral expression of the Coxsackie and adenovirus receptor (CAR), which mediates adenoviral entry. Retargeting the adenoviral vector to other cellular receptors, by inserting an arginine-glycine-aspartate (RGD) tripeptide in the fiber knob, might overcome this problem. METHODS: Four esophageal carcinoma cell lines and 10 fresh surgical resection specimens were cultured. All were infected with the native adenovirus (Ad) and the retargeted adenovirus (AdRGD), encoding for the reporter genes luciferase or Green Fluorescent Protein to analyze gene transfer efficiency. RESULTS: In all cell lines, an increase in viral expression per cell and an increase in the percentage of transduced cells were seen with the retargeted adenovirus. Also, in the primary cultures of carcinoma cells, a more efficient gene transfer was seen when the retargeted vector was used. This phenomenon was less pronounced in normal cells, indicating that the RGD virus transduces tumor cells more efficiently than normal cells. CONCLUSIONS: This study demonstrates that an RGD retargeted adenovirus infects human esophageal carcinoma cells with enhanced efficiency, while in normal esophageal cells this effect is less pronounced. Therefore, this retargeted vector is expected to have a better performance in vivo, when compared with nonretargeted vectors used for cancer gene therapy so far.     

Augmenting major histocompatibility complex class I expression by murine tumors in vivo enhances antitumor immunity induced by an active immunotherapy strategy

OBJECTIVE: Tumors down-regulate major histocompatibility complex class I expression, escaping recognition by the cellular immune response. We hypothesized that augmentation of tumor cell class I expression by interferon-gamma would enhance the cellular antitumor immune response and cure rate of an active immunotherapy strategy. METHODS: B16.F10 tumor cells were exposed to interferon-gamma in culture, and class I expression was quantified using flow cytometry. Syngeneic mice bearing established tumors were injected with interferon-gamma (5000 U, intraperitoneal), and class I expression was assessed using immunohistochemistry. Tumor-specific cytotoxic T lymphocytes were induced in mice by an intratumoral injection of AdCD40L (5 x 10(10) particles), an adenovirus gene transfer vector-based immunotherapy strategy previously demonstrated to augment cellular antitumor immunity. A conjugate-formation assay and the enzyme-linked immunospot assay were used to evaluate the binding and activation of cytotoxic T lymphocytes, respectively. Interferon-gamma was administered to tumor-bearing mice concomitantly with intratumoral AdCD40L. End points measured included the frequencies of cytotoxic T lymphocytes using the enzyme-linked immunospot assay, tumor size, and mouse survival. The role of class I expression was further evaluated by monoclonal antibody blockade in both in vitro and in vivo experiments. RESULTS: B16.F10 cells exposed to interferon-gamma expressed significantly more class I, both in vitro and in vivo, and were able to bind to and activate cytotoxic T lymphocytes more efficiently than untreated cells. Cytotoxic T-lymphocyte frequencies, tumor regression, and the cure rate induced by AdCD40L were augmented by the addition of a single dose of interferon-gamma in tumor-bearing mice. These in vitro and in vivo effects of interferon-gamma were attenuated by class I monoclonal antibody blockade. CONCLUSIONS: Up-regulation of class I expression using interferon-gamma enhances the cellular antitumor immune response and cure rate of AdCD40L, an active immunotherapy strategy. This approach may be useful for human tumors that lack class I expression.     

携带Fas基因重组腺病毒治疗瘢痕疙瘩的体内实验研究

目的 研究携带人Fas基因的两种重组腺病毒对瘢痕疙瘩的体内治疗效果。方法 构建瘢痕疙瘩裸鼠模型,应用携带Fas基因的常规腺病毒Ad—Fas（T）和细菌内重组腺病毒Ad—Fas（B）注射及Fas单克隆抗体（FasMcab）辅助对植入裸鼠皮下的瘢痕疙瘩组织进行治疗。通过大体观察、常规病理及电镜观察检测瘢痕疙瘩组织的变化。结果 单纯使用腺病毒注射的瘢痕疙瘩组织块体积仅轻度缩小。前期注射Ad—Fas（B）或Ad—Fas（T）后,应用FasMcab作为后续治疗,瘢痕疙瘩组织块均明显缩小,HE染色证实瘢痕疙瘩组织结构遭到破坏,电镜观察发现细胞凋亡证据。结论 重组腺病毒Ad—Fas（B）及Ad—Fas（T）的瘢痕疙瘩基因治疗效果令人满意。为瘢痕疙瘩的治疗提供了新途径。     

Gene transfer to the thymus. A means of abrogating the immune response to recombinant adenovirus.

OBJECTIVE: The authors investigated whether adenoviral gene transfer to the thymus could be accomplished in vivo and whether immunologic unresponsiveness to recombinant adenovirus could be induced by intrathymic inoculation. SUMMARY BACKGROUND DATA: A major barrier to the clinical application of adenovirus-mediated gene therapy for diseases requiring long-lasting gene expression is the immunogenicity of adenoviral vectors, which limits the duration of its effects. In other experimental models, intrathymic inoculation of foreign proteins or cells has proven to be an effective means to induce immunologic tolerance. METHODS: The efficiency of gene transfer to the mouse thymus after direct inoculation of recombinant adenovirus was compared with that of several other vectors. Animals inoculated with adenovirus-infected pancreatic islets into the thymus were tested for unresponsiveness to the virus with a subsequent challenge of adenovirus administered into the liver by intravenous injection. RESULTS: Adenovirus accomplished highly efficient gene transfer to the thymus, unlike plasmid DNA, DNA-liposome complexes, retrovirus, and adeno-associated virus. Adenoviral transgene expression was transient in the thymus of immunocompetent mice but persistent in CD8+ T-cell-deficient and severe combined immunodeficiency (SCID) mice, implicating the role of cytotoxic T lymphocytes in viral clearance. Intrathymic transplantation of syngeneic pancreatic islet cells infected with adenovirus impaired the normal antiviral cytotoxic T-lymphocyte response and prolonged hepatic transgene expression after an intravenous challenge with adenovirus. CONCLUSIONS: Recombinant adenovirus accomplishes highly efficient gene transfer to the thymus in vivo. Intrathymic inoculation of adenovirus-infected islets can be used to induce immunologic unresponsiveness to the adenoviral vector and, potentially, to other proteins that it might be engineered to encode.     

Fas-Fas ligand signaling pathway mediates an interleukin-12-induced rejection of a murine prostate tumor system

BACKGROUND: Recent data suggest that anti-tumor activities of interleukin-12 (IL-12) involve the induction of apoptosis. Fas (APO-1/CD95) is a type I membrane protein that is capable of initiating an apoptosis signaling pathway when bound to its ligand (FasL). We undertook this study to test the hypothesis that Fas-FasL-mediated apoptosis plays a role in IL-12-induced tumor regression. METHODS: An mIL-12 expression vector driven by cytomegalovirus promoter was used to express murine IL-12 cDNA in the RM-9 murine prostate carcinoma cell line. Control RM-9 cells and RM-9 cells stably transfected with IL-12 gene (RM-9-IL12) were inoculated subcutaneously in 4- to 6-week-old male C57BL/J6 mice. Tumor size was measured every 3 days. Western blot and immunohistochemical assays were used to evaluate Fas and FasL protein expression. In situ fluorescent end labeling was used to label apoptotic cells. RESULTS: IL-12-expressing RM-9 prostate carcinoma cells transplanted into C57BL/J6 mice grew more slowly than control RM-9 cells and vector control RM-9-Luc cells. The average survival time of the RM-9-IL12 mice was longer than 53 days, whereas the mean survival for mice transplanted with control RM-9 cells was only 16 days. Apoptotic cells were more numerous in RM-9-IL12 tumors: 10.3% vs. 1.5% in control (P = 0.001). Fas and FasL proteins were increased approximately twofold in the RM-9-IL12 tumors compared with the RM-9 control tumors as determined by Western blot and immunohistochemical analyses (P < 0.05). CONCLUSION: The Fas-FasL-mediated apoptosis pathway may contribute to the IL-12-induced rejection of prostate carcinoma.     

Adenovirus-mediated CD40 ligand therapy induces tumor cell apoptosis and systemic immunity in the TRAMP-C2 mouse prostate cancer model

BACKGROUND: The interaction between CD40 ligand (CD40L) and CD40 on antigen presenting cells is essential for the initiation of antigen-specific T-cell responses, whereas CD40L stimulation of CD40+ tumor cells can induce cellular apoptosis. We investigated the anti-tumor effects induced by CD40L gene transfer into the mouse prostate adenocarcinoma cell line TRAMP-C2, both in vitro and in vivo. METHODS: TRAMP-C2 cells were transduced with an adenoviral vector encoding CD40L (AdCD40L). The induced expression of co-stimulatory molecules and cell viability was analyzed. AdCD40L-transduced TRAMP-C2 cells were used in prophylactic vaccination studies, while therapeutic studies were performed using peritumoral injections of AdCD40L. RESULTS: AdCD40L yielded reduced TRAMP-C2 cell viability and induced apoptosis in vitro. Vaccination with CD40L-expressing TRAMP-C2 cells induced anti-tumor immunity and peritumoral AdCD40L injections induced tumor growth suppression. CONCLUSIONS: Our observations highlight the therapeutic potential of using AdCD40L as a monotherapy or in combination with conventional chemotherapy or novel therapies (e.g., oncolytic viruses). The use of AdCD40L offers an attractive option for future clinical trials.     

反义K-ras基因对胰腺癌细胞增殖和凋亡的影响

目的 探讨反义K-ras癌基因对胰腺癌细胞增殖和凋亡及Fas/FasL、Bcl-2、Bax表达的影响.方法 将重组逆转录病毒载体pLXSN转染包装细胞PT-67,获得重组逆转录病毒.在细胞和动物水平将该重组逆转录病毒分别感染PC-3和BxPC-3胰腺癌细胞,经G418筛选获得稳定细胞系,应用MTT、流式细胞仪和免疫组化法分别研究其增殖、凋亡及其相关基因表达情况.结果 成功制备含反义K-ras基因的重组逆转录病毒.感染含反义K-ras基因重组病毒后,胰腺癌PC-3细胞和移植瘤(有K-ras基因第12密码子点突变GGT→GTT)增殖受到抑制,G<,0/1>期细胞增加而S期细胞明显减少,细胞凋亡增加.免疫组化显示含反义K-ras癌基因逆转录病毒感染后PC-3细胞Bax/Bcl-2比值升高,Fas表达上调.结论 反义K-ras基因可使胰腺癌细胞及移植瘤增殖受到抑制,并可通过上调Bax/Bcl一2比值和(或)促进Fas表达诱导细胞凋亡.     

重组腺病毒载体介导人OSM 基因对胰腺癌细胞增殖的抑制作用及对裸鼠致瘤性的影响

目的　构建了含人抑瘤素M (humanoncostatinM ,hosm)基因的复制缺陷型重组腺病毒载体 ,观察其对胰腺癌细胞株BxPC3 在体外生长抑制情况及在裸鼠致瘤性改变的作用 ,为胰腺癌的基因治疗提供参考。方法　用含hosm基因的缺陷型腺病毒载体转染人胰腺癌细胞株 ,用RT PCR法检测外源hosm基因在其中的表达 ;苔盘蓝染色、细胞计数法检测ad hosm对BxPC3 的体外增殖抑制情况 ;裸鼠皮下接种转染ad hosm的BxPC3 ,观察其对肿瘤形成率的影响。结果　hosm基因在转染细胞能有效的表达。体外试验示ad hosm能明显抑制BxPC3 的生长 ,ad hosm能抑制BxPC3 在裸鼠中的成瘤作用。结论　重组腺病毒介导hosm基因表达能有效抑制BxPC3 在体外、体内的增殖 ,提示重组腺病毒介导的hosm基因治疗可能成为胰腺癌治疗的侯选方案。     

顺铂联合胞嘧啶脱氨酶自杀基因对直肠癌细胞杀伤作用的研究

目的探讨顺铂联合胞嘧啶脱氨酶(CD)自杀基因对直肠腺癌细胞8348的杀伤作用。方法以绿色荧光蛋白(GFP)基因作为报告基因,观察在顺铂作用下GFP基因对8348细胞的转染效率;用克隆形成试验观察顺铂对CD基因转染效率的影响;同时用四甲基偶氮唑盐(MTT)试验检测顺铂联合CD/5-氟胞嘧啶(5-FC)对8348细胞的杀伤作用。结果顺铂提高质粒对8348细胞的转染效率26倍。对腺癌细胞的杀伤效率:单纯转染CD基因组为14.9%;IC50的氟尿嘧啶(5-FU)联合CD基因组为54.9%;IC50的顺铂联合CD基因组为88.5%,与其他两组相比,对癌细胞杀伤效率明显增强(P<0.01)。结论顺铂联合CD自杀基因能更有效地杀伤直肠腺癌细胞,可成为治疗直肠癌术后复发及转移的一种有效的方法。     

Combined gene therapy with adenovirus vectors containing CTLA4Ig and CD40Ig prolongs survival of composite tissue allografts in rat model

BACKGROUND: The blockade of costimulatory signal pathway by anti-CD40 ligand antibody or cytotoxic T lymphocyte antigen 4 immunoglobulin (CTLA4Ig) prolongs allograft survival in various vascularized organ transplantations. Because of the short half life of these agents, repeated administration of proteins is required to achieve significant graft survival. Furthermore, there is limited information regarding the effect of cosimulatory blockade on the survival of composite tissue allografts. Therefore, we examined the effect of adenovirus-mediated gene transfer of CTLA4Ig or CD40Ig gene or both in composite tissue allotransplantation. METHODS: The hind limbs removed from male ACI rats (RT1 ) were transplanted into female Lewis rats (RT1 ) heterotopically. The recombinant adenovirus carrying CTLA4Ig (AxCTLA4Ig) or CD40Ig (AxCD40Ig) was intravenously administered after limb transplantation. RESULTS: Limb allograft survival was significantly prolonged by either AxCTLA4Ig or AxCD40Ig treatment at 1 x 10 plaque forming unit (mean survival time [MST] of 39.4+/-6.0 and 13.0+/-2.9, respectively) compared with the adenovirus vector containing beta-galactosidase-treated group (MST of 4.8+/-0.8). Combination of AxCTLA4Ig and AxCD40Ig led to significant prolongation of graft survival (MST of 49.2+/-6.6). Serum levels of CD40Ig were higher in rats treated with combination therapy than those treated with AxCD40Ig alone, whereas the serum levels of CTLA4Ig in rats treated with AxCTLA4Ig alone and AxCTLA4Ig and AxCD40Ig combined were very similar. CONCLUSION: This study indicates that an adenovirus-mediated gene therapy of CTLA4Ig or CD40Ig has a therapeutic potential for preventing rejection in composite tissue transplantation. Furthermore, a combination therapy of AxCTLA4Ig and AxCD40Ig was even more effective in preventing acute rejection and prolonging the survival of allografted limbs without apparent complication.     

阿霉素上调肿瘤细胞Fas基因表达并诱导凋亡的实验研究

目的 研究化疗药物阿霉素(ADM)对肿瘤细胞Fas凋亡基因的调控，并探讨其致凋亡机制。方法 逆转录一聚合酶链反应(RT-PCR)比较经。ADM处理前后肿瘤细胞胃癌ADM细胞系SGG-7901、MGC-803和肺癌细胞系A-549的Fas mRNA的表达水平，同时观察其对抗Fas抗体的敏感性，并用流式细胞术检测肿瘤细胞凋亡率。结果 所有3种肿瘤细胞在ADM作用下Fas表达水平显著增强，差异有统计学意义(P＜0．05)，同时肿瘤细胞凋亡率明显增加(凋亡率分别为40．3％、43．6％、54．4％)。ADM能增加肿瘤细胞对Fas抗体的敏感性。结论 ADM上调肿瘤细胞Fas的表达，ADM与Fas抗体联合应用将增强肿瘤细胞的凋亡率，有一定的抗肿瘤临床应用前景。     

FasL逆转录病毒转移体系的建立及其在肝癌细胞中的表达

目的　研究Fas/FasL系统的生物学功能,探讨转FasL基因治疗肿瘤的可行性。方法将大鼠FasL全长cDNA亚克隆到逆转录病毒载体pLXSN中,获得FasL正向单拷贝插入子pLXSN/FasL     

In vivo gene transfer of pigment epithelium-derived factor inhibits tumor growth in syngeneic murine models of thoracic malignancies

OBJECTIVE: Pigment epithelium-derived factor is known to be an inhibitor of angiogenesis. We hypothesized that in vivo gene transfer of pigment epithelium-derived factor may inhibit tumor angiogenesis and growth in syngeneic models of thoracic malignancies. METHODS: An adenovirus vector encoding the human pigment epithelium-derived factor cDNA (AdPEDF) was used to transduce human lung cancer cells in vitro. Transgene expression was assessed using Western analysis. Three different murine flank tumors (2 lung, 1 colon) were then established in syngeneic mice and treated intratumorally with phosphate-buffered saline, AdPEDF, or an empty vector (AdNull). Endpoints measured included transgene expression, tumor size, and animal survival, as well as microvessel density within the tumor. Additionally, a murine pulmonary metastasis model was established by intravenous injection of a syngeneic colon adenocarcinoma cell line expressing a marker gene (beta-galactosidase). One day later, treatment (phosphate-buffered saline, AdNull, or AdPEDF) was administered intrapleurally. Tumor burden (gross and histologic inspection, lung weight, and beta-galactosidase expression) was then evaluated 13 days after vector dosing, and survival was recorded. RESULTS: AdPEDF-derived expression of pigment epithelium-derived factor was demonstrated in vitro and in vivo. In syngeneic murine lung cancer flank tumors, intratumoral administration of AdPEDF significantly inhibited tumor growth (P <.01), prolonged mouse survival (P <.01), and decreased microvessel density (P <.01) compared with control groups. In the pulmonary metastasis model, AdPEDF-treated mice exhibited significantly reduced lung lesions, lung weight (P <.0005), beta-galactosidase expression (P <.05), and animal survival was prolonged (P <.05). CONCLUSION: Gene transfer of pigment epithelium-derived factor suppresses tumor vascularization and growth, while prolonging survival in syngeneic murine models of thoracic malignancies.     

Cisplatin enhances apoptosis induced by a tumor-selective adenovirus expressing tumor necrosis factor-related apoptosis-inducing ligand

BACKGROUND: Cancer cells frequently exhibit resistance to the cytotoxic effect of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL). Pretreatment of TRAIL-resistant cells with cisplatin sensitizes them to this ligand. Cisplatin also has been shown to enhance adenoviral transgene expression. OBJECTIVE: This study aims to evaluate the ability of cisplatin to enhance the expression and the cytotoxic effect of the tumor-specific adenoviral vector Ad/gTRAIL, which expresses a green fluorescent protein-TRAIL fusion protein. METHODS: Cultured cancer cells and normal human cells were infected with Ad/gTRAIL with or without cisplatin pretreatment. Adenoviral transgene expression was determined by using flow cytometry to measure green fluorescent protein fluorescence. Cytotoxicity was measured by using thiazolyl blue tetrazolium bromide assays and an apoptosis enzyme-linked immunosorbent assay kit. RESULTS: Green fluorescent protein-TRAIL fusion protein expression was significantly enhanced by cisplatin pretreatment in cancer cells. Cisplatin treatment before Ad/gTRAIL infection resulted in a 2- to 12-fold increase in green fluorescent protein fluorescence intensity across cancer lines. Although Ad/gTRAIL induced mild cytotoxicity in all cancer lines (inhibitory concentration of 50% values of >500 pfu/cell), pretreatment with cisplatin resulted in a dose-dependent enhancement of Ad/gTRAIL-mediated cytotoxicity, as indicated by the drastic reduction of inhibitory concentration of 50% values to 4 to 42 pfu/cell in all cell lines. There was no cytotoxicity noted in normal cells treated with both cisplatin and Ad/gTRAIL. CONCLUSION: Cisplatin pretreatment enhances Ad/gTRAIL cytotoxicity in malignant cells while not affecting normal cells. The mechanisms underlying this effect might include both enhancement of the susceptibility of cisplatin-treated cells to TRAIL and cisplatin-mediated enhancement of TRAIL expression in Ad/gTRAIL infected cells. These findings provide a rationale for development of Ad/gTRAIL-based therapy for thoracic malignancies.