Angiostatin enhances B7.1-mediated cancer immunotherapy independently of effects on vascular endothelial growth factor expression.

Tumors must develop an adequate vascular network to meet their increasing demands for nutrition and oxygen. Angiostatin, a multiple kringle (1-4)-containing fragment of plasminogen, is an effective natural inhibitor of tumor angiogenesis. Here we show that gene transfer of angiostatin into small (0.1 cm in diameter) solid EL-4 lymphomas established in syngeneic C57BL/6 mice led to reduced tumor angiogenesis and weak inhibition of tumor growth. In contrast, when angiostatin gene therapy was preceded by in situ gene transfer of the T-cell costimulator B7.1, large (0.4 cm in diameter) tumors were rapidly and completely eradicated, whereas B7.1 and angiostatin monotherapies were ineffective. Combined gene transfer of B7.1 and angiostatin generated potent systemic antitumor immunity that was effective in eradicating a systemic challenge of 10(7) EL-4 cells. Gene transfer of angiostatin expression plasmids led to overexpression of angiostatin in tumors, increased apoptosis of tumor cells, and decreased density of tumor blood vessels, which may allow the immune system to overcome tumor immune resistance. The latter effects were not the result of a decrease in vascular endothelial growth factor expression, as tumoral vascular endothelial growth factor expression increased slightly after angiostatin gene transfer, presumably in response to increasing hypoxia. These results suggest that combining immunogene therapy with a vascular attack by angiostatin is a particularly effective approach for eliciting antitumor immunity.     

Vascular attack by 5,6-dimethylxanthenone-4-acetic acid combined with B7.1 (CD80)-mediated immunotherapy overcomes immune resistance and leads to the eradication of large tumors and multiple tumor foci

The promise of cancer immunotherapy is that it will not only eradicate primary tumors but will generate systemic antitumor immunity capable of destroying distant metastases. A major problem that must first be surmounted relates to the immune resistance of large tumors. Here we reveal that immune resistance can be overcome by combining immunotherapy with a concerted attack on the tumor vasculature. The functionally related antitumor drugs 5,6-dimethylxanthenone-4-acetic acid (DMXAA) and flavone acetic acid (FAA), which cause tumor vasculature collapse and tumor necrosis, were used to attack the tumor vasculature, whereas the T-cell costimulator B7.1 (CD80), which costimulates T-cell proliferation via the CD28 pathway, was used to stimulate antitumor immunity. The injection of cDNA (60-180 microg) encoding B7.1 into large EL-4 tumors (0.8 cm in diameter) established in C57BL/6 mice, followed 24 h later by i.p. administration of either DMXAA (25 mg/kg) or FAA (300 mg/kg), resulted in complete tumor eradication within 2-6 weeks. In contrast, monotherapies were ineffective. Both vascular attack and B7.1 immunotherapy led to up-regulation of heat shock protein 70 on stressed and dying tumor cells, potentially augmenting immunotherapy. Remarkably, large tumors took on the appearance of a wound that rapidly ameliorated, leaving perfectly healed skin. Combined therapy was mediated by CD8+ T cells and natural killer cells, accompanied by heightened and prolonged antitumor cytolytic activity (P < 0.001), and by a marked increase in tumor cell apoptosis. Cured animals completely rejected a challenge of 1 x 10(7) parental EL-4 tumor cells but not a challenge of 1 x 10(4) Lewis lung carcinoma cells, demonstrating that antitumor immunity was tumor specific. Adoptive transfer of 2 x 10(8) splenocytes from treated mice into recipients bearing established (0.8 cm in diameter) tumors resulted in rapid and complete tumor rejection within 3 weeks. Although DMXAA and B7.1 monotherapies are complicated by a narrow range of effective doses, combined therapy was less dosage dependent. Thus, a broad range of amounts of B7.1 cDNA were effective in combination with 25 mg/kg DMXAA. In contrast, DMXAA, which has a very narrow range of high active doses, was effective at a low dose (18 mg/kg) when administered with a large amount (180 microg) of B7.1 cDNA. Importantly, combinational therapy generated heightened antitumor immunity, such that gene transfer of B7.1 into one tumor, followed by systemic DMXAA treatment, led to the complete rejection of multiple untreated tumor nodules established in the opposing flank. These findings have important implications for the future direction and utility of cancer immunotherapies aimed at harnessing patients' immune responses to their own tumors.     

Arsenic trioxide synergizes with B7H3-mediated immunotherapy to eradicate hepatocellular carcinomas

Arsenic trioxide (As(2)O(3)), a valuable anticancer drug for the treatment of acute promyelocytic leukemia, may also have therapeutic potential for the treatment of solid tumors. However, its therapeutic efficacy against solid tumors is lacking even at high dosages. Other therapeutic strategies are required to enhance the efficacy of As(2)O(3) against solid tumors such as hepatocellular carcinoma (HCC), which is refractory to chemotherapy. B7H3, a new member of the B7 family, has been shown to induce antitumor immunity. Intratumoral injection of B7H3 plasmids eradicates small EL-4 lymphomas, but monotherapy is ineffective against large tumors. Here we investigated whether As(2)O(3) would synergize with B7H3 immunotherapy to combat HCC. Large subcutaneous H22 HCCs (0.7-0.8 cm in diameter) established in BALB/c mice were rapidly and completely eradicated when intratumoral administration of As(2)O(3) was preceded by in situ gene transfer of B7H3. In contrast, neither As(2)O(3) nor B7H3 monotherapy was effective. The antitumor activity of As(2)O(3) was attributed to increased tumor-cell apoptosis, perhaps as a result of direct cytotoxicity as well as decreased tumor angiogenesis. Combination therapy generated potent systemic antitumor immunity mediated by CD8(+) and NK cells that was effective in combating a systemic challenge of 1 x 10(7) parental H22 cells. It led to the simultaneous and complete regression of multiple distant tumor nodules, concomitant with increased levels of serum IFN-gamma and cytotoxic T lymphocyte (CTL) activity. In conclusion, combining B7H3-mediated immunotherapy with As(2)O(3) warrants investigation as a therapeutic strategy to combat HCC, and other malignancies.     

抗胃癌生物活性肽对荷胃癌裸鼠酯酶同工酶代谢的影响

本文观察了协同刺激分子B7-1某因导入小鼠EL-4淋巴瘤细胞后在小鼠体内诱导的抗瘤效应.结果表明,逆转录病毒(PLXSN)载体重组的小鼠B7-1基因表达质粒导入小鼠EL-4淋巴瘤细胞,经有限稀释法克隆后获得高表达的B7-1~ EL-4细胞.B7-1~ 瘤细胞的形态,体外增殖能力及MHC Ⅰ类分子表达水平与野生型肿瘤细胞无显著差别,但致瘤性显著降低,用野生型肿瘤致死剂量接种C57BL/6小鼠完全排斥.同时免疫原性明显增强,以X-线灭活的B7-1~ 肿瘤细胞免疫后小鼠获得了对随后致死剂量野生型细胞攻击的免疫保护作用.以X-线灭活的肿瘤细胞作为瘤苗进行实验性免疫治疗,对早期(接种7天)形成的肿瘤有一定的治疗效果,但时晚期(接种14天)肿瘤.B7-1和B7-1~ 瘤细胞都未显示出明显的治疗效果.上述结果提示肿瘤细胞表达B7-1分子可有效激发机体的抗肿瘤免疫应答.     

Heat shock protein 70 gene therapy combined with hyperthermia using magnetic nanoparticles

Heat shock proteins (HSPs) are recognized as significant participants in immune reactions. We previously reported that expression of HSP70 in response to hyperthermia, produced using our original magnetite cationic liposomes (MCLs), induces antitumor immunity. In the present study, we examine whether the antitumor immunity induced by hyperthermia is enhanced by hsp70 gene transfer. A human hsp70 gene mediated by cationic liposomes was injected into a B16 melanoma nodule in C57BL/6 mice in situ. At 24 hours after the injection of the hsp70 gene, MCLs were injected into melanoma nodules in C57BL/6 mice, which were subjected to an alternating magnetic field for 30 minutes. The temperature at the tumor reached 43 degrees C and was maintained by controlling the magnetic field intensity. The combined treatment strongly arrested tumor growth over a 30-day period, and complete regression of tumors was observed in 30% (3/10) of mice. Systemic antitumor immunity was induced in the cured mice. This study demonstrates that this novel therapeutic strategy combining the use of hsp70 gene therapy and hyperthermia using MCLs may be applicable to patients with advanced malignancies.     

GM-CSF gene or B7-1 gene modified murine EL-4 cells vaccine

Since 1990, gene transduced tumor vaccine has been studied. Many articles reported that tumor cells transduced with some cytokine or costimulatory molecule could induce system antitumor immunity[1,2] In this study, EL-4 lymphoma was transduced with recombinant retrovirus containing the murine GM-CSF gene and B7-1 gene, respectively. The effect of gene transduction on antitumor immunity was investigated.MATERIALS AND METHODSMice and Cell Lines Female C57BL/6 mice were bought from …     

Requirements for ICAM-1 immunogene therapy of lymphoma

Intercellular cell adhesion molecule-1 (ICAM-1) is a cell-surface glycoprotein capable of eliciting bidirectional signals that activate signalling pathways in leukocytes, endothelial, and smooth muscle cells. Gene transfer of xenogeneic ICAM-1 into EL-4 lymphomas causes complete tumor rejection; however, it is unknown whether the mechanism responsible involves the "foreignness" of the ICAM-1 transgene, bidirectional signalling events, ICAM-1-receptor interaction, or a combination of the latter. To begin to address this question, we constructed four different therapeutic expression vectors encoding full-length ICAM-1, and forms in which the N-terminal ligand-binding domains and cytoplasmic tail had been deleted. Mouse EL-4 tumors (0.5 cm in diameter), which actively suppress the immune response, were significantly inhibited in their growth following injection of expression plasmids encoding either full-length xenogenic (human) ICAM-1, or a functional cytoplasmic domain-deficient form that retains ligand-binding activity. Efficacy of ICAM-1-mediated antitumor immunity was significantly augmented by administration of the antivascular drug 5,6-dimethylxanthenone-4-acetic acid (DMXAA), which suppressed blood supply to the tumor, leading to enhanced leukocyte infiltration, and complete tumor eradication in a gene dosage and CD8(+) T cell and NK cell-dependent fashion. Generation of potent cytotoxic T cell (CTL)-mediated antitumor immunity was reflected by ICAM-1-facilitated apoptosis of tumor cells in situ. In contrast, nonfunctional ICAM-1 lacking the N-terminal ligand-binding Ig domain failed to generate antitumor immunity, even in the presence of DMXAA. These studies demonstrate that ICAM-1-stimulated antitumor immunity can overcome tumor-mediated immunosuppression, particularly when employed in combination with an attack on the tumor vasculature. The ligand-binding domain of ICAM-1 is essential for generating antitumor immunity, whereas the cytoplasmic domain and bidirectional activation of tumor signalling pathways are not essential.     

Inhibitory effects of B cells on antitumor immunity

B-cell functions in antitumor immunity are not well understood. In this study, we evaluated the role of B cells in the development of antitumor immunity using Friend murine leukemia virus gag-expressing mouse EL-4 (EL-4 gag), D5 mouse melanoma, or MCA304 mouse sarcoma cells. To screen tumors for susceptibility to B-cell-deficient immune environments, spleen cells from naive C57BL/6 [wild-type (WT)] and B-cell knockout (BKO) mice were cultured with irradiated tumor cells in vitro. When cells were stimulated with EL-4 gag or D5 (but not MCA304 tumors), IFN-gamma production from CD8 T cells and natural killer cells was markedly decreased in WT compared with BKO cultures. IFN-gamma production was correlated with CD40 ligand expression on the tumor and inversely with interleukin-10 (IL-10) production by B cells. Sorted WT B cells produced more IL-10 than CD40 knockout (CD40KO) B cells when cocultured with EL-4 gag or D5 (but not MCA304). IFN-gamma production by BKO cells was reduced by the addition of sorted naive WT B cells (partially by CD40KO B cells) or recombinant mouse IL-10. In vivo tumor progression mirrored in vitro studies in that WT mice were unable to control tumor growth whereas EL-4 gag and D5 tumors (but not MCA304) were eliminated in BKO mice. Robust in vivo antitumor CTLs developed only in BKO tumor-challenged mice. Our studies provide the first mechanistic basis for the concept that B-cell depletion could therapeutically enhance antitumor immune responses to certain tumors by decreasing IL-10 production from B cells.     

Immunomodulatory gene therapy with interleukin 12 and 4-1BB ligand: long- term remission of liver metastases in a mouse model

BACKGROUND: The success of immunomodulatory cancer therapy is frequently hampered by the transient nature of the antitumor immune response. We have shown previously in a mouse model that interleukin 12 (IL-12) generates a strong natural killer (NK) cell-mediated antitumor response and reduces liver metastases induced by a colon carcinoma cell line. However, only a small percentage of the treated animals developed the cytotoxic T-lymphocytic response required for a long-term systemic antitumor immunity. 4-1BB is a co-stimulatory molecule expressed on the surface of activated T cells. Interaction of 4-1BB with its natural ligand (4-1BBL) has been shown to amplify T-cell (especially CD8+)-mediated immunity. In this study, we investigated the effects of adenovirus-mediated gene therapy delivering both IL-12 and 4-1BBL genes on mice with hepatic metastases induced by colon cancer cells. METHODS: Syngeneic BALB/c mice received intrahepatic injection of poorly immunogenic MCA26 colon cancer cells. Various combinations of replication-defective adenoviruses expressing IL-12 and 4-1BBL genes were injected into the established liver tumors. Changes in tumor size and animal survival were then monitored. All statistical tests were two-sided. RESULTS: The long-term survival rate of mice treated with the combination of IL-12 and 4-1BBL was significantly improved over that of animals in the control group (P =.0001). In vivo depletion of NK cells or CD8+ T cells completely abolished the long-term survival advantage of the IL-12 plus 4-1BBL-treated animals (P<.002). Moreover, the systemic immunity induced by this combination treatment protected these animals against a subcutaneous challenge with parental MCA26 cells. CONCLUSION: Adenovirus-mediated transfer of IL-12 and 4-1BBL genes directly into liver tumors resulted in tumor regression that required both NK and CD8+ T cells and generated a potent, long-lasting antitumor immunity.     

Potent tumor-specific immunity induced by an in vivo heat shock protein-suicide gene-based tumor vaccine

Tumor cells harbor a repertoire of unique, mutated antigens and shared self-antigens but generally are incapable of provoking an effective immune response, likely because of inadequate antigen presentation by professional antigen-presenting cells. Heat shock proteins (HSPs) play important roles in eliciting innate and adaptive immunity by chaperoning peptides for antigen presentation and providing endogenous danger signaling. Although effective in inducing tumor-specific immunity in mice and in some clinical trials, tumor-derived HSPs have many limitations like vaccines, such as the technical difficulty of ex vivo preparation of adequate quantities of HSPs from the resected tumors of individual patients. Here we have developed an in vivo HSP-suicide gene tumor vaccine by generating a recombinant replication-defective adenovirus (Ad-HT) that coexpresses HSP70 and a herpes simplex virus thymidine kinase suicide gene. The combination of HSP70 overexpression in situ and tumor killing by thymidine kinase/ganciclovir treatment, but neither strategy alone, provoked potent systemic antitumor activities after intratumor injection of Ad-HT. Tumor-specific CD4+ and CD8+ T-cell responses were induced by Ad-HT intratumor injection. CD11c+ dendritic cells (DCs) isolated from mice treated with Ad-HT were able to prime tumor-specific CTLs. Collectively, these results indicate that the combination of tumor killing by activation of a suicide gene to release tumor antigens and in situ HSP70 overexpression to enhance DC antigen presentation overcomes host immune tolerance to tumor antigens, leading to the induction of potent antitumor immunity. Our findings may have broad relevance to the use of the in vivo HSP/suicide gene tumor vaccine in therapy for human solid tumors.     

Anti-angiogenic therapy subsequent to adeno-associated-virus-mediated immunotherapy eradicates lymphomas that disseminate to the liver

Liver cancer has a very poor prognosis and lacks effective therapy. We have previously demonstrated that intraportal injection of adeno-associated-viral (AAV) particles that express angiostatin lead to long-term expression of angiostatin capable of suppressing the outgrowth of EL-4 tumors in the liver. Here we combine AAV-mediated angiostatin therapy with immunotherapy by employing an AAV vector encoding the T-cell costimulator B7.1. Incubation of EL-4 cells with AAV-B7.1 viruses resulted in the rapid expression of B7.1 on the surface of 80% of EL-4 cells. Mice that were vaccinated with B7.1-engineered tumor cells rejected the tumor cells and resisted a secondary challenge with unmodified parental cells. Splenocytes from the vaccinated mice were highly cytotoxic towards parental EL-4 cells in vitro. However, the vaccinated mice failed to resist the challenge of a heavy burden of EL-4 cells. Intraportal injection of AAV particles that express angiostatin into mice that had been vaccinated 1 month earlier with B7.1-engineered tumor cells protected mice against the challenge of a heavy burden of EL-4 cells and eradicated tumors that had disseminated to the liver. The combinational therapy increased the survival rate of mice with advanced liver cancer. These encouraging results warrant investigation of the employment of anti-angiogenic therapy subsequent to cancer immunotherapy for targeting unresectable disseminated liver metastases.     

ANTITUMOR IMMUNITY AND VACCINE EFFECT INDUCED BY IL—12 SYNERGIZES B7—1 GENE TRANSFECTED CELLS

Cytokines play an crucial role in the induction of antitumor immunity. It have been demonstrated that cytokines such as IL-2, IL-4, IL-12 could stimulate immunity response in many basic and clinical experiment[1-3]. Interleukin 12 (IL-12) is a heterodimeric cytokine which consists of p40 and p35 subunits. It stimulates the proliferation and activation of T lymphocyte and other killer cells and induces the production of IFN-g by these cells[4, 5]. IL-12 promotes T helper type 1 responses.…     

Protection of zinc against tumor necrosis factor induced lethal inflammation depends on heat shock protein 70 and allows safe antitumor therapy

Tumor necrosis factor (TNF)-induced inflammation prevents its broad application as an antitumor agent. We here report that addition of ZnSO(4) to the drinking water of mice induces expression of heat shock protein 70 (HSP70) in several organs, notably the gastrointestinal track. Zinc conferred dose-responsive protection against TNF-induced hypothermia, systemic induction of interleukin-6 and NO(x), as well as against TNF-induced bowel cell death and death of the organism. The protective effect of zinc was completely absent in mice deficient in the major HSP70-inducible gene, hsp70.1, whereas transgenic mice constitutively expressing the human HSP70.A gene, under control of a beta-actin promoter, was also protected against TNF, indicating that an increase in HSP70 is necessary and sufficient to confer protection. The therapeutic potential of the protection induced by ZnSO(4) was clearly shown in a TNF/IFNgamma-based antitumor therapy using three different tumor models. In hsp70.1 wild-type mice, but not in hsp70.1-deficient mice, zinc very significantly protected against lethality but left the antitumor effect intact. We conclude that zinc protects against TNF in a HSP70-dependent way and that protection by zinc could be helpful in developing a safer anticancer therapy with TNF/IFNgamma.     

Combination B7-Fc fusion protein treatment and Treg cell depletion therapy.

PURPOSE: A B7.1 fusion protein consisting of the extracellular domains of human B7.1 and the Fc portion of human IgG1, called B7.1-Fc, was generated and evaluated for its antitumor potential when used alone or in combination with regulatory T (Treg) cell depletion. METHODS: A human B7.1-Fc fusion protein was constructed, expressed, purified, and examined for its antitumor activity in experimental mouse tumor models. RESULTS: Soluble B7.1-Fc showed costimulatory activity of T-cell proliferation in vitro, and when given in vivo, it induced complete regression of Colon 26 tumors after a 5-day treatment regimen. Parallel studies with human B7.2-Fc gave very similar results in the Colon 26 tumor model. Even in mice with established RENCA and Madison 109 tumors, which are poorly immunogenic, B7.1-Fc treatment slowed tumor growth dramatically. In these models, more potent antitumor activity was achieved when B7.1-Fc was used in combination with Treg depletion by i.p. administration of antibody PC61. Rechallenge experiments done with mice that had sustained complete tumor regressions showed that these mice had immunologic memory by their ability to reject subsequent implants. Histologically, B7.1-Fc treatment induced multiple areas of necrosis and infiltration of CD4+ and CD8+ T cells in tumors along with a concomitant dramatic increase in T-cell proliferation in tumor-draining lymph nodes. CONCLUSIONS: The B7.1-Fc fusion protein seems to be an effective antitumor agent especially in combination with Treg depletion. Its potency in stimulating immune responses and its human origin suggest that clinical studies may be warranted in the future.     

Efficient inducation of local and systemic antitumor immune response by liposome-mediated intratumoral co-transfer of interleukin-2 gene and interleukin-6 gene.

Interleukin 2 (IL-2) expressing plasmid and interleukin 6 (IL-6)-expressing plasmid were encapsulated in liposome and administrated intratumoraly into tumor-bearing mice 4 days after subcutaneous inoculation of B16F10 melanoma cells. The results showed that treatment of tumor-bearing mice with IL-2 gene or IL-6 gene transfer inhibited the growth of subcutaneous tumor and prolonged the survival of tumor-bearing mice significantly when compared with the treatment of PBS or control gene transfer mediated by liposome (P < 0.01). Combined transfer of IL-2 gene and IL-6 gene was found to elicit inhibitory effects on the growth of B16F10 tumor more significantly and prolonged the survival period of tumor-bearing mice more obviously. We investigated the local immunity in tumor microenvironment and found that IL-2 and IL-6 gene transfer could significantly increase the expression of lymphocyte function-associated antigen-1 on tumor infiltrating lymphocytes (TIL) and MHC-I molecule on tumor cells freshly isolated from the tumor mass. The NK and CTL activity of TIL increased markedly after the combined transfer of these two cytokine genes. We also observed the systemic antitumor immune response in the tumor-bearing mice and demonstrated that NK and CTL activity of splenocytes and the production of IL-2, tumor necrosis factor and interferon-gamma from splenocytes increased obviously in mice after the combined transfer of IL-2 and IL-6 gene. In conclusion, local and systemic antitumor immunity of the tumor-bearing host could be induced efficiently after the combined gene transfer. The enhanced specific and non-specific antitumor immunity might be responsible for the more potent antitumor effects of the combined gene therapy.     

Antitumor activity of α-pinene in T-cell tumors

T-cell acute leukemia and lymphoma have a poor prognosis. Although new therapeutic agents have been developed, their therapeutic effects are suboptimal. α-Pinene, a monoterpene compound, has an antitumor effect on solid tumors; however, few comprehensive investigations have been conducted on its impact on hematologic malignancies. This report provides a comprehensive analysis of the potential benefits of using α-pinene as an antitumor agent for the treatment of T-cell tumors. We found that α-pinene inhibited the proliferation of hematologic malignancies, especially in T-cell tumor cell lines EL-4 and Molt-4, induced mitochondrial dysfunction and reactive oxygen species accumulation, and inhibited NF-κB p65 translocation into the nucleus, leading to robust apoptosis in EL-4 cells. Collectively, these findings suggest that α-pinene has potential as a therapeutic agent for T-cell malignancies, and further investigation is warranted.     

Role of 4-1BB:4-1BB ligand in cancer immunotherapy

The activation of T cells plays a central role in antitumor immunity. In order to activate na?ve T cells, two key signals are required. Signal one is provided through the T-cell receptor (TCR) while signal two is that of costimulation. The CD28:B7 molecules are one of the best-studied costimulatory pathways, thought to be the main mechanism through which primary T-cell stimulation occurs. However, a number of molecules have been identified which serve to amplify and diversify the T-cell response, following initial T-cell activation. These include the more recently described 4-1BB:4-1BB ligand (4-1BBL) molecules. 4-1BB:4-1BBL are a member of the TNFR:TNF ligand family, which are expressed on T cells and antigen-presenting cells (APCs), respectively. Therapies utilizing the 4-1BB:4-1BBL signaling pathway have been shown to have antitumor effects in a number of model systems. In this paper, we focus on the 4-1BB:4-1BBL costimulatory molecules. In particular, we will describe the structure and function of the 4-1BB molecule, its receptor and how 4-1BB:4-1BBL costimulation has and may be used for the immunotherapy of cancer.     

ANTITUMOR EFFECTS INDUCED BY B7-1 GENE MODIFIED EL-4 LYMPHOMA COOPERATED WITH IL-2 IN VIVO AND IN VITRO

ＡＮＴＩＴＵＭＯＲＥＦＦＥＣＴＳＩＮＤＵＣＥＤＢＹＢ７１ＧＥＮＥＭＯＤＩＦＩＥＤＥＬ４ＬＹＭＰＨＯＭＡＣＯＯＰＥＲＡＴＥＤＷＩＴＨＩＬ２ＩＮＶＩＶＯＡＮＤＩＮＶＩＴＲＯＷｕＡｉｍｉｎ武爱民ＺｈａｎｇＹｕｅｊｉａｎ张跃建ＱｉｎＨｕｉｌｉａｎ秦慧...     

树突状细胞与髓性白血病的免疫治疗 *

目的：我们应用逆转录病毒构建了ＩＬ－１２,Ｂ－７和ＧＭ－ＣＳＦ表达载体,以研究基因修的肿瘤细胞的癌疫苗作用。方法：将３种表达载体分别转染ＥＬ－４胞腺瘤细胞并研究了该基因导入细胞的抗肿瘤免疫效果。结果：当接种子ＥＬ４／ＩＬ－１２细胞后,在Ｃ５７ＰＬ／６同系鼠中其基因导入细胞的肿瘤原性比较ＥＬ４／Ｗｔ和ＥＬ－４／Ｎｅｏ组明显减少（Ｐ〈０．０１）。在ＥＬ４／ＩＬ－１２被排斥后,体内试验中诱发了实验动物抗     

Effects of survivin antagonists on growth of established tumors and B7-1 immunogene therapy

BACKGROUND: Survivin, a member of the inhibitor of apoptosis (IAP) protein family, is detectable in most types of cancer, and its presence is associated with a poor prognosis. We determined the effects of gene-based therapies that inhibit survivin function in a mouse tumor model. METHODS: Using five to six mice per treatment group, we injected tumors derived from mouse EL-4 thymic lymphoma cells with plasmids encoding antisense survivin, a dominant-negative mutant survivin, and the T-cell costimulator B7-1. Expression of endogenous survivin and the proteins encoded by the injected plasmids were examined by immunohistochemical staining of tumor sections and by western blot and flow cytometry analyses of isolated tumor cells. Tumor growth, the generation of antitumor cytotoxic T-lymphocyte (CTL) activity, apoptosis, and the contribution of leukocyte subsets to antitumor activity were measured. All statistical tests were two-sided. RESULTS: Large (1.0-cm diameter) tumors had approximately 10-fold more survivin than small (0.2-cm diameter) tumors. At 28 days after injection, antisense and dominant-negative mutant survivin plasmids statistically significantly inhibited the growth of both small (P =.006 and P =.0018, respectively) and large (P<.001 for both plasmids) EL-4 tumors compared with tumors injected with empty plasmid. The growth of large tumors was further inhibited by intratumoral injection with antisense survivin and B7-1 (P =.004); thus, inhibition of survivin expression renders large tumors susceptible to B7-1-mediated immunotherapy. Mice whose tumors were completely eradicated by injection of B7-1 remained tumor free for 26 days after re-injection with EL-4 cells (when the experiment ended). Compared with tumors injected with empty plasmid, tumors injected with survivin-based plasmids had increased apoptosis, and animals bearing such tumors generated more antitumor CTLs. CONCLUSION: Intratumoral injection of plasmids that block survivin expression and stimulate the generation of tumor-specific CTLs may be beneficial for the treatment of large lymphomas.