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Query: UMLS:C0598934 (tumor growth)
58,965 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The 38C13 murine lymphoma model was used to examine the role T cell activation plays in anti-CD3-based bispecific antibody therapy by comparing two bispecific antibody preparations that vary in their ability to activate T cells. Prior studies demonstrated that lower dose bispecific IgG (BsIgG) induced nonspecific T cell activation in vitro and in vivo, whereas bispecific F(ab')2 [bsF(ab')2] did not. BsIgG was more effective than bsF(ab')2 at prolonging survival of tumor-bearing mice. BsF(ab')2 was effective at prolonging survival when used along with IL-2. When used at a lower dose, the antitumor effect of both preparations was specific in that it was limited to cells bearing the target antigen. In contrast, larger doses of bsIgG, but not bsF(ab')2, resulted in regression of antigen-negative tumor, and so had therapeutic effects that were nonspecific. Serum from mice treated with larger dose bsIgG contained IFN-gamma that inhibited the growth of tumor cells in vitro. We conclude that two distinct mechanisms of action are playing a role in the observed antitumor effects. BsF(ab')2 and lower dose bsIgG inhibit tumor growth by retargeting T cells. Higher dose bsIgG also results in nonspecific T cell activation and systemic cytokine production that induces tumor regression.
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PMID:T cell activation and cytokine production in anti-CD3 bispecific antibody therapy. 858 75

NKR-P1 has been identified as a triggering structure selectively expressed on rat natural killer (NK) cells and adherent lymphokine-activated killer (A-LAK) cells. In vivo treatment with anti-NKR-P1 monoclonal antibody (mAb 3.2.3) was shown to induce complete inhibition of NK cytotoxicity and elimination of LAK cell precursors in Lewis and Fisher rat strains. We investigated the effects of mAb 3.2.3 in a colon tumor model in BDIX rats. Inoculation of animals with mAb 3.2.3 even at very high doses induced a strong but incomplete inhibition of NK cytotoxicity in nylon-wool-non-adherent spleen and peripheral blood cells. Generation of adherent A-LAK cells from their spleen precursors was also strongly by not fully inhibited. We also investigated the effect of treatment with mAb 3.2.3 on the tumorigenicity of the NK-sensitive REGb cell line. When subcutaneously inoculated in syngeneic animals, REGb cells induce tumors that first grow for 2 weeks, then spontaneously regress and disappear. In contrast with previous results using anti-asialoGM1, no significant difference in tumor growth was observed between rats treated with mAB 3.2.3 and control animals, even with a long-term treatment. In vitro, mAb 3.2.3 exhibited the same incomplete efficiency. Nylon-wool-non-adherent spleen cells treated with mAb 3.2.3 plus complement were completely free of 3.2.3(bright) cells, but retained a substantial NK activity and generated LAK cells after culture with IL-2. After an overnight incubation in standard medium of 3.2.3-depleted spleen cells, 3.2.3(bright) cells were partially recovered and the NK cytotoxic activity, as well as the generation of LAK cells, was significantly enhanced. These results suggest that a strong expression of NKR-P1 is not required for BDIX mononuclear cells to exhibit NK function and generate LAK cells under IL-2 activation.
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PMID:High expression of NKR-P1 is not an absolute requirement for natural killer activity in BDIX rats. 862 62

Interleukin-12 (IL-12) is a recently described immunoregulatory cytokine with potent therapeutic activity in various preclinical models of infectious or malignant disease. As part of our ongoing evaluation of potential mechanisms accounting for the potent antitumor activity of IL-12, we have investigated the influence of IL-12 administration on total serum nitrate/nitrite (NO(x)(-)) levels and the production of nitric oxide (NO) by peritoneal macrophages from normal and tumor-bearing mice. We report here that IL-12 administration to either normal or tumor-bearing mice for periods of time ranging from 7-19 days induced progressive increases in serum NO(x)(-) levels and primed peritoneal macrophages for NO production on subsequent exposure to lipopolysaccharide or IL-2 ex vivo. Treatment of resident peritoneal macrophages or the macrophage cell line ANA-1 with IL-12 alone or IL-12 in combination with various other stimuli failed to induce NO production, suggesting that the effects of IL-12 occurred via an indirect mechanism. Furthermore, we have shown that not only was the production of NO by macrophages from untreated long-term, tumor- bearing mice suppressed compared with control mice treated with vehicle or IL-12, but also that IL-12 administration overcame this suppression and delayed tumor growth. Lastly, we have shown that administration of weekly pulses of IL-2 in combination with IL-12 additively enhanced the priming of macrophages for NO production ex vivo and delayed tumor growth far more effectively than either agent alone. These observations and reports in the literature regarding the potential influence of NO on development of the immune response and on the regulation of tumor growth and vascularization suggest that NO may play a significant role in the antitumor activity of IL-12 and IL-2.
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PMID:Interleukin 12 primes macrophages for nitric oxide production in vivo and restores depressed nitric oxide production by macrophages from tumor-bearing mice: implications for the antitumor activity of interleukin 12 and/or interleukin 2. 864 Jul 72

Genetically engineered tumor cells secreting immunostimulatory molecules could facilitate the obtention of a vaccination against tumor antigens. To test this approach, we transfected genes encoding for rat and mouse IL-2 into PROb cells. These cells originate from a dimethylhydrazine induced colon carcinoma of BD IX rats. We observed an inhibition of the in vivo tumor growth directly proportional to the IL-2 secretion. An immunohistochemical analysis revealed that the tumors were infiltrated by leucocytes expressing the IL-2 receptor, suggesting their activation within the tumor. A strong delay of tumor growth was observed in rats challenged with PROb cells after a previous rejection of IL-2 secreting cells. Yet two rats out of six were completely protected. This protection is specific since rejection of PROb-IL-2 does not confer protection towards the syngeneic glioma A15A5. In addition, we could show by depletion experiments that NK/LAK, CD8, and CD4 lymphocytes were involved in the rejection of cells secreting large amounts of IL-2. Macrophages appear to be involved in the rejection process too, but also in the induction of an immune memory. Vaccination experiments using irradiated PROb IL-2 cells were performed. Only a partial protection towards a challenge with parental PROb cells could be obtained, also depending on the amount of secreted IL-2: the best protection being obtained after vaccination with cells synthesizing a small amount of IL-2. However, this protection was not superior to that obtained by coinjection of irradiated PROb cells and BCG.
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PMID:[Vaccination with genetically modified IL-2 secreting cells in a rat model of colonic carcinoma]. 869 24

We have systematically observed in the present study the anticarcinogenic and immunomodulatory effects of 4-Seleno-carageenan (Se-carra) as well as their possible mechanisms of actions in vivo and in vitro. It was found that se-carra had inhibitory effects on tumor growth in vivo and in vitro. The underlying mechanisms of this tumor suppressive effect may be related with the activation of macrophages, followed by the indirect priming of lymphocytes to release effector molecules such as IL-2, to express IL-2 receptors, and to selectively suppress the synthesis of macromolecules in tumor cells. The results imply that Se-carra has dual functions of tumor cell-killing effect and immunostimulating effect, therefore may serve as a novel immuno-cytotoxic anticarcinogenic drug.
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PMID:[Studies on the anticarcinogenic and immunomodulatory actions of 4-seleno-carrageenan]. 873 82

The non-tumorigenic cells of X63-Ag8.653 mouse plasmocytoma line transfected with murine interleukin 2 cDNA (X63-mIL-2) served us as the source of the cytokine to induce or to augment antitumor response in syngeneic BALB/c or semisyngeneic (CD2F1) mice challenged subcutaneously with either "wild" line tumor cells (X63/0) or with non-related methylcholantrene induced BFS1 fibrosarcoma of BALB/c mice. When applied peritumorally in several injections (2 to 6) to mice with non-advanced stages of the tumors, IL-2-secreting cells were able to cause tumor growth retardation in most of the treated mice and to induce tumor rejection in some of them. The combination chemoimmunotherapy was attempted in mice with advanced BFS1 fibrosarcoma using compound CBM-4A (the bromoanalog of ifosfamide) administered at various time (4 h or 3, 5 or 7 days) before the first of two local injections of transfected cells. The strategy proved to be more efficient in the tumor growth inhibition as compared with the cytostatic alone.
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PMID:Growth inhibition of transplantable tumors in mice by mIL-2-secreting murine plasmocytoma cells used alone or in combination with a cytostatic agent. 874 48

Interleukin 12 (IL-12) is a heterodimeric cytokine with a number of biological effects that are consistent with its potential role as an antitumor agent. The antimetastatic and antitumor activities of IL-12 have been demonstrated in a number of murine tumor models. Both the inhibition of established experimental pulmonary or hepatic metastases and a reduction in spontaneous metastases have been achieved by treatment with murine IL-12. Systemic treatment of mice bearing subcutaneous tumors with IL-12 results in tumor growth inhibition, prolongation of survival, and, in some models, tumor regression. The antitumor effect of IL-12 in these models is dose-dependent and can be initiated against well-established tumors. Mice cured of their tumor by IL-12 treatment are specifically immune to rechallenge with the same tumor. A series of experiments have demonstrated that both T-cells and interferon-gamma (IFN-gamma) induction are necessary for the optimal antitumor effects of IL-12. However, the antitumor efficacy of IL-12 has not been observed after exogenous administration of murine IFN-gamma, suggesting that additional factors may be important for the antitumor effects of IL-12. In several tumor models, IL-12 is more active or has a larger therapeutic window than either IL-2 or IFN-alpha, two cytokines with demonstrated antitumor activity against human malignancies. Combining IL-12 with other cytokines or chemotherapeutic drugs can improve antitumor effects.
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PMID:Antitumor activity of interleukin 12 in preclinical models. 876 10

Previous studies showed that gammaIFN decreases metastatic hepatic tumor growth by stimulating Kupffer cells (KC). The present studies examine whether lymphocyte stimulation via cells engineered to secrete GM-CSF or IL-2 decreases hepatic tumor growth, and whether stimulation of both macrophages and lymphocytes is more effective than either individually. Rats were immunized with irradiated hepatoma cells transduced by herpes viral amplicon vectors containing the genes for GM-CSF, IL-2 or LacZ. On day 18, half of each group was treated with 5 x 10(4) U gammaIFN, or saline intraperitoneally for 3 d. On day 21, all rats received 5 x 10(5) hepatoma cells intrasplenically. On day 41, rats were killed and tumor nodules were counted. Separate rats underwent splenocyte and KC harvest for assessment of lymphocyte- and macrophage-mediated tumor cell kill in vitro. GM-CSF or IL-2 vaccines or gammaIFN decreased tumor nodules significantly (GM-CSF 13+/-4, IL-2 14+/-6 vs. control 75+/-24, P < 0.001). Combination therapy was more effective, and completely eliminated tumor in 4 of 12 IFN-GM-CSF and 8 of 11 IFN-IL-2 animals. Additional rats underwent partial hepatectomy, an immunosuppressive procedure known to accelerate the growth of hepatic tumor, following tumor challenge. Therapy was equally effective in this immunosuppressive setting. Vaccination is associated with enhancement of splenocyte-mediated tumoricidal activity, whereas the effect of gammaIFN is mediated by KC. GM-CSF and IL-2 vaccine therapy and pretreatment with gammaIFN represent effective strategies in reducing hepatic tumor. Combination therapy targets both lymphocytes and macrophages, and is more effective in reducing tumor than either therapy alone.
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PMID:Prevention of hepatic tumor metastases in rats with herpes viral vaccines and gamma-interferon. 904 85

Tumor regression in experimental systems has been linked to the activities of Th1 cells. It is, therefore, conceivable that Th2 cells interrupt the expression of tumor immunity since interleukin-4 (IL-4) and IL-10 inhibit the generation of Th1 from precursors and modulate the competence of antigen-presenting cells to activate this lymphocyte subpopulation. Naive murine renal cell carcinoma (renca) cells (1 x 10(5)) were implanted into the subcapsule of the left kidney of Balb/c and Balb/c nude mice at 6-8 weeks of age. After 14 days, Th2 cytokine (IL-4 and IL-10) mRNAs as well as transforming growth factor beta1 mRNA, assessed by reverse transcriptase/polymerase chain reaction were upregulated in the spleen of hosts upon naive renca tumor acceptance, while Th1 cytokine (IL-2 and interferon gamma) mRNAs were almost undetectable. In the renca tumor, IL-10 mRNA was detected but IL-2, interferon gamma, and IL-4 were not. Intraperitoneal administration of anti-(mouse IL-4) mAb (11B11) reduced the renca tumor size (P = 0.018) and prolonged host survival (P = 0.03), but did not reduce the acceptance rate of the tumor (P = 0.18). However, prior depletion of CD4+ or CD8+ cells with monoclonal antibodies abrogated the antitumor effects of anti-IL-4 mAb. In addition, the significant antitumor effect of anti-IL-4 mAb was not observed in Balb/c nude hosts. Renca cells were transfected with the mammalian expression vector pCAGGS containing murine IL-4 cDNA or vector alone, then stable IL-4 transfectants (RencaL or RencaH, low- or high-IL-4-producing respectively) and control renca cells (RencaC) were obtained. RencaL cells, RencaH cells, or RencaC cells (1 x 10(5) each) were implanted into the subcapsule of the left kidney of Balb/c, Balb/c nude, and allogenic C3H/HeJ mice, then tumor formation was evaluated 14 days later. When RencaH cells were innoculated into syngeneic Balb/c hosts, tumor volume was marginally suppressed (P = 0.03) and tumors tended to be rejected (P = 0.06) compared with RencaC cells. However, those effects were not observed in Balb/c nude mice. RencaC, RencaL, and RencaH cells were not accepted by allogeneic C3H mice with or without FK506 administration or donor-specific transfusion. The administration of anti-(mouse IL-4) mAb to Balb/c mice significantly suppressed renca tumor growth by a CD4+ and CD8+ T-cell-dependent mechanism. By contrast, relatively high levels of IL-4 production by renca cells and T cells seemed to be required to induce the rejection and growth suppression of IL-4-producing renca cells in syngeneic hosts.
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PMID:Th2-like response and antitumor effect of anti-interleukin-4 mAb in mice bearing renal cell carcinoma. 906 10

This review first summarizes the different strategies of gene therapy of cancer and then focuses on the immunological approach. Several studies in animal models with cytokine gene-transduced tumor cells indicate that local cytokine release usually results in tumor growth inhibition. Moreover, in a number of cases vaccination with such cells can reduce growth of established tumors or even cure the tumor-bearing animals. Translation of such a principle in human clinical setting is reported. We have transduced human melanoma cells with genes coding for interleukin (IL)-2, IL-4 or B7-1 and characterized such lines. The phenotype did not change after gene insertion but the functional, immunostimulatory activity of IL-2 or B7-1 gene-transduced melanoma cells was significantly increased compared to that of parental lines. These-lines were then used to vaccinate melanoma patients. Preliminary results of trials with IL-2 gene-transduced cells are presented which indicate a weak clinical response and the activation of a melanoma-specific cytotoxic T lymphocyte response in a low percentage of patients.
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PMID:Cytokine-based gene therapy of human tumors. An overview. 915 40


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