1
|
Marron TU, Hammerich L, Brody J. Local Immunotherapies of Cancer. Oncoimmunology 2018. [DOI: 10.1007/978-3-319-62431-0_28] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
|
2
|
Rashid OM, Takabe K. Animal models for exploring the pharmacokinetics of breast cancer therapies. Expert Opin Drug Metab Toxicol 2015; 11:221-30. [PMID: 25416501 PMCID: PMC4583421 DOI: 10.1517/17425255.2015.983073] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
INTRODUCTION Despite massive expenditures in research and development to cure breast cancer, few agents that pass preclinical trials demonstrate efficacy in humans. Although this endeavor relies on murine models to screen for efficacy before progressing to clinical trials, historically there has been little focus on the validation of these models, even in the era of targeted therapy where understanding the genetic signatures of tumors under study is critical. AREAS COVERED This review includes the transgenic, xenograft, and syngeneic murine breast cancer models, the ectopic, orthotopic and intravenous methods of cell implantation, and the ethics of animal experimentation. It also includes the latest data on tumor gene expression and the issues to consider when exploring the pharmacokinetics and efficacy of breast cancer therapies. EXPERT OPINION Breast cancer drug development is expensive and inefficient without a consensus preclinical murine model. Investigators must approach the choice of murine model with the same sophistication that is applied to the choice of in vitro assays to improve efficiency. Understanding the limitations of each model available, including the nuances of tumor gene signatures, is critical for investigators exploring the phamacokinetics and efficacy of breast cancer therapies, especially in the context of gene profiling and individualized targeted therapy.
Collapse
Affiliation(s)
- Omar M. Rashid
- Division of Surgical Oncology, Department of Surgery, Virginia Commonwealth University School of Medicine and the Massey Cancer Center, Richmond, VA
- H. Lee Moffitt Cancer Center and Research Institute, Tampa, FL
| | - Kazuaki Takabe
- Division of Surgical Oncology, Department of Surgery, Virginia Commonwealth University School of Medicine and the Massey Cancer Center, Richmond, VA
- Department of Biochemistry and Molecular Biology, Virginia Commonwealth University School of Medicine and the Massey Cancer Center, Richmond, VA
| |
Collapse
|
3
|
Tandon M, Vemula SV, Sharma A, Ahi YS, Mittal S, Bangari DS, Mittal SK. EphrinA1-EphA2 interaction-mediated apoptosis and FMS-like tyrosine kinase 3 receptor ligand-induced immunotherapy inhibit tumor growth in a breast cancer mouse model. J Gene Med 2012; 14:77-89. [PMID: 22228563 DOI: 10.1002/jgm.1649] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND The receptor tyrosine kinase EphA2 is overexpressed in several types of cancers and is currently being pursued as a target for breast cancer therapeutics. The EphA2 ligand EphrinA1 induces EphA2 phosphorylation and intracellular internalization and degradation, thus inhibiting tumor progression. The hematopoietic growth factor, FMS-like tyrosine kinase 3 receptor ligand (Flt3L), promotes expansion and mobilization of functional dendritic cells. METHODS We tested the EphrinA1-EphA2 interaction in MDA-MB-231 breast cancer cells focusing on the receptor-ligand-mediated apoptosis of breast cancer cells. To determine whether EphrinA1-EphA2 interaction-associated apoptosis and Flt3L-mediated immunotherapy would have an additive effect in inhibiting tumor growth, we used an immunocompetent mouse model of breast cancer to evaluate intratumoral (i.t.) inoculation strategies with human adenovirus (HAd) vectors expressing either EphrinA1 (HAd-EphrinA1-Fc), Flt3L (HAd-Flt3L) or a combination of EphrinA1-Fc + Flt3L (HAd-EphrinA1-Fc + HAd-Flt3L). RESULTS In vitro analysis demonstrated that an EphrinA1-EphA2 interaction led to apoptosis-related changes in breast cancer cells. In vivo, three i.t. inoculations of HAd-EphrinA1-Fc showed potent inhibition of tumor growth. Furthermore, increased inhibition in tumor growth was observed with the combination of HAd-EphrinA1-Fc and HAd-Flt3L accompanied by the generation of an anti-tumor adaptive immune response. CONCLUSIONS The results obtained in the present study, indicating the induction of apoptosis and inhibition of mammary tumor growth, show the potential therapeutic benefits of HAd-EphrinA1-Fc. In combination with HAd-Flt3L, this represents a promising strategy for effectively inducing mammary tumor regression by HAd vector-based therapy.
Collapse
Affiliation(s)
- Manish Tandon
- Department of Comparative Pathobiology, Purdue University Center for Cancer Research, and Bindley Bioscience Center, Purdue University, West Lafayette, IN 47907, USA
| | | | | | | | | | | | | |
Collapse
|
4
|
King GD, Muhammad AKMG, Curtin JF, Barcia C, Puntel M, Liu C, Honig SB, Candolfi M, Mondkar S, Lowenstein PR, Castro MG. Flt3L and TK gene therapy eradicate multifocal glioma in a syngeneic glioblastoma model. Neuro Oncol 2007; 10:19-31. [PMID: 18079358 DOI: 10.1215/15228517-2007-045] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The disseminated characteristics of human glioblastoma multiforme (GBM) make it a particularly difficult tumor to treat with long-term efficacy. Most preclinical models of GBM involve treatment of a single tumor mass. For therapeutic outcomes to translate from the preclinical to the clinical setting, induction of an antitumor response capable of eliminating multifocal disease is essential. We tested the hypothesis that expression of Flt3L (human soluble FMS-like tyrosine kinase 3 ligand) and TK (herpes simplex virus type 1-thymidine kinase) within brain gliomas would mediate regression of the primary, treated tumor mass and a secondary, untreated tumor growing at a distant site from the primary tumor and the site of therapeutic vector injection. In both the single-GBM and multifocal-GBM models used, all saline-treated control animals succumbed to tumors by day 22. Around 70% of the animals bearing a single GBM mass treated with an adenovirus expressing Flt3L (AdFlt3L) and an adenovirus expressing TK (AdTK + GCV) survived long term. Approximately 50% of animals bearing a large primary GBM that were implanted with a second GBM in the contralateral hemisphere at the same time the primary tumors were being treated with AdFlt3L and AdTK also survived long term. A second multifocal GBM model, in which bilateral GBMs were implanted simultaneously and only the right tumor mass was treated with AdFlt3L and AdTK, also demonstrated long-term survival. While no significant difference in survival was found between unifocal and multifocal GBM-bearing animals treated with AdFlt3L and AdTK, both treatments were statistically different from the saline-treated control group (p < 0.05). Our results demonstrate that combination therapy with AdFlt3L and AdTK can eradicate multifocal brain tumor disease in a syngeneic, intracranial GBM model.
Collapse
Affiliation(s)
- Gwendalyn D King
- Gene Therapeutics Research Institute, Cedars-Sinai Medical Center, Department of Molecular and Medical Pharmacology, University of California Los Angeles 90048, USA
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
5
|
Ryschich E, Huszty G, Wentzensen N, Schmidt E, Knaebel HP, Encke J, Märten A, Büchler MW, Schmidt J. Effect of Flt3 ligand gene transfer in experimental pancreatic cancer. Int J Colorectal Dis 2007; 22:215-23. [PMID: 16528542 DOI: 10.1007/s00384-006-0118-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 02/03/2006] [Indexed: 02/04/2023]
Abstract
BACKGROUND Fms-like tyrosine kinase 3 receptor (Flt3) is an important receptor expressed on the cell membrane of immature antigen-presenting cells. The binding of Flt3 to its ligand (FL) activates the proliferation of dendritic cells (DCs). This mechanism is currently being evaluated in the therapy of malignant tumors. The aim of the present study was to study the effect of FL gene transfer on the immune response and tumor growth in experimental pancreatic cancer. MATERIALS AND METHODS The rat FL was sequenced and cloned from total mRNA extract of the spleen. Transfection efficiency of subcutaneously growing rat duct-like pancreatic cancer (DSL6A) with DOTAP-/cholesterol-based liposomes was tested using a pcDNA3.1-lacZ construct. Flt3 ligand production of in vitro transfected tumor cells and in vivo transfected tumors was measured by enzyme-linked immunosorbent assay. Tumor induction was achieved in Lewis rats by a subcutaneous inoculation of syngeneic pancreatic tumor cells (DSL6A). The animals were allocated into three groups: control, mock treatment, and treatment with FL plasmid. The plasmid was injected intratumorally three times per week for 2 weeks. The total observation time was 6 weeks. RESULTS The tumor volume was significantly lower in the FL-transfected group during the first 3 weeks. The number of responders was significantly higher in the FL group compared with control and mock treatment. The number of CD80+ DCs in the spleen was significantly higher after FL gene transfer. The responders showed a significantly higher number of splenic natural killer (NK) cells. There were no differences of infiltrating lymphocytes, proliferation, and tumor blood vessels between the groups. CONCLUSION Intratumoral gene transfer of FL in rats activated proliferation of DCs and NK cells, which causes a moderate reduction of tumor growth. This improvement of local tumor control during the first weeks could be explained by an improved antigen presentation.
Collapse
Affiliation(s)
- E Ryschich
- Dept. of Surgery, University of Heidelberg, Im Neuenheimer Feld 110, 69120 Heidelberg, Germany
| | | | | | | | | | | | | | | | | |
Collapse
|
6
|
Abstract
Selection of mouse models of cancer is often based simply on availability of a mouse strain and a known compatible tumor. Frequently this results in use of tumor models long on history but short on homology and quality control. Other factors including genetics, sex, immunological status, method and site of tumor implantation, technical competence, biological activity of the tumor, protocol sequence and timing, and selection of endpoints interact to produce outcomes in tumor models. Common reliance on survival and tumor burden data in a single mouse model often skews expectations towards high remission and cure rates; a finding seldom duplicated in clinical trials. Inherent limitations of tumor models coupled with the advent of new therapeutic targets reinforce need for careful attention to design, conduct, and stringent selection of in vivo and ex vivo endpoints. Preclinical efficacy testing for anti-tumor therapies should progress through a series of models of increasing sophistication that includes incorporation of genetically engineered animals, and orthotopic and combination therapy models. Pharmacology and safety testing in tumor-bearing animals may also help to improve predictive value of these models for clinical efficacy. Trends in bioinformatics, genetic refinements, and specialized imaging techniques are helping to maintain mice as the most scientifically and economically powerful model of malignant neoplasms.
Collapse
Affiliation(s)
- JoAnn C L Schuh
- Applied Veterinary Pathobiology, Bainbridge Island, Washington 98110-3663, USA.
| |
Collapse
|
7
|
Somers KD, Brown RR, Holterman DA, Yousefieh N, Glass WF, Wright GL, Schellhammer PF, Qian J, Ciavarra RP. Orthotopic treatment model of prostate cancer and metastasis in the immunocompetent mouse: efficacy of flt3 ligand immunotherapy. Int J Cancer 2004; 107:773-80. [PMID: 14566827 DOI: 10.1002/ijc.11464] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
We established an orthotopic treatment model of prostate cancer to generate reproducible primary and metastatic carcinoma in immunocompetent C57BL/6 mice. Using an in vivo selection scheme of intraprostatic implantation of TRAMP-C1 cells, primary prostate tumors were cultured and recycled three times by intraprostatic injection resulting in the selection and establishment of the recycled cell line TRAMP-C1P3. Prostate tumors were detected approximately 30 days post-implantation with periaortic lymph node metastasis in 19/20 (95%) of mice. Tissue culture amplification, DNA ploidy and PCR amplification of the SV40 transgene were used to detect metastatic TRAMP-C1P3 in lymph node specimens. Tissue culture amplification and DNA ploidy were as sensitive as SV40 transgene amplification by PCR in detection of early metastatic disease in draining lymph nodes. To establish the use of the orthotopic model of prostate cancer for immunotherapy, mice were injected orthotopically with TRAMP-C1P3 cells and 7 days post-implantation treated daily for 28 days with either flt3L or carrier control. Carrier-treated mice had clinically detectable prostate tumors, lymph node metastasis and were moribund at 29-35 days, whereas flt3L therapy markedly suppressed primary TRAMP-C1P3 growth and lymph node metastasis, and prolonged survival. In summary, we have established a reproducible and clinically relevant orthotopic treatment model of prostate cancer in immunocompetent mice with application to a variety of therapeutic strategies. We demonstrate that flt3L treatment suppressed orthotopic prostate tumor growth and lymph node metastasis reinforcing a role for flt3L as an immunotherapeutic strategy for prostate cancer.
Collapse
Affiliation(s)
- Kenneth D Somers
- Departments of Microbiology and Molecular Cell Biology, Eastern Virginia Medical School, Norfolk, VA 23507, USA.
| | | | | | | | | | | | | | | | | |
Collapse
|
8
|
Tourkova IL, Yamabe K, Chatta G, Shurin GV, Shurin MR. NK Cells Mediate Flt3 Ligand-Induced Protection of Dendritic Cell Precursors In Vivo from the Inhibition by Prostate Carcinoma in the Murine Bone Marrow Metastasis Model. J Immunother 2003; 26:468-72. [PMID: 14595214 DOI: 10.1097/00002371-200311000-00002] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Multiple observations suggest that suppression of the dendritic cell (DC) system might be one of the mechanisms used by the tumors to escape immune response. However, no in vivo data are available to support these in vitro observations. Here we have shown that murine prostate cancer inhibits DC generation (dendropoiesis) from the bone marrow precursors in the in vivo model in mice injected intrafemorally with RM1 prostate adenocarcinoma cells. Phenotyping of DC, generated from in vivo RM1-treated bone marrow cells, revealed a significant inhibition of dendropoiesis assessed as a percentage of CD11c+MHCII+, CD11c+CD86+, and CD11c+CD80+ cells. The stimulatory capacity of these DCs to induce T cell proliferation was also markedly decreased. Notably, Flt3 ligand-based therapy reversed the inhibitory effects of prostate cancer on dendropoiesis in vivo in wild-type and C.B-17 SCID (T and B cell deficient) mice, but not in SCID beige (T, B, and NK cell deficient) animals, suggesting a key role of NK cells in Flt3 ligand-mediated protection of dendropoiesis from tumor-induced inhibition in vivo. Thus, these data demonstrate that prostate cancer inhibits DC hematopoietic precursors in vivo in the bone marrow and this effect could be abolished by a systemic administration of growth factor Flt3 ligand.
Collapse
Affiliation(s)
- Irina L Tourkova
- Department of Pathology, University of Pittsburgh Medical Center, Pittsburgh, PA 15213, USA
| | | | | | | | | |
Collapse
|
9
|
Liu Y, Huang H, Chen Z, Zong L, Xiang J. Dendritic cells engineered to express the Flt3 ligand stimulate type I immune response, and induce enhanced cytoxic T and natural killer cell cytotoxicities and antitumor immunity. J Gene Med 2003; 5:668-80. [PMID: 12898636 DOI: 10.1002/jgm.387] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
BACKGROUND Tumor antigen presentation by dendritic cells (DCs) to T cells in lymphoid organs is crucial for induction of antitumor immune responses. Fms-like tyrosine kinase 3 ligand (Flt3L) is a regulator of hematopoietic cell development. METHODS To investigate the potential effect of Flt3L transgene expression on DC-based cancer vaccines, we constructed a recombinant adenovirus AdVFlt3L expressing Flt3L, transfected DCs with AdVFlt3L, and investigated the efficacy of antitumor immunity by vaccination of DC(Flt3L) engineered to express Flt3L transgene. RESULTS Our data demonstrated that AdVFlt3L transfection up-regulated the expression of cytokine IL-1beta and chemokines MIP-1alpha, MIP-1beta, IP-10, MCP-1 and MIP-2, and stimulated DC(Flt3L) cell proliferation in vitro and migration toward regional lymph nodes in vivo. Our data also demonstrated that vaccination of Mut1-pulsed DC(Flt3L) cells was able to stimulate (i). a type 1 immune response comprising CD4(+) Th1 and CD8(+) Tc1 activation and (ii). around 2- and 3-fold enhanced tumor-specific cytotoxic T lymphocyte (CTL) and non-specific NK responses (p < 0.05) than vaccination with similarly pulsed control virus-transfected and untransfected DCs, respectively. More importantly, vaccination of Mut1-pulsed DC(Flt3L) cells induced enhanced antitumor immunity in vivo, even against poorly immunogenic 3LL tumor cells. Vaccinations of Mut1-pulsed DCs, DC(pLpA) and DC(Flt3L) all protected mice from challenge of low dose (0.5 x 10(5)) tumor cells. However, only vaccination of the last one was able to protect 63% (6/8) mice from challenge of high dose (3 x 10(5)) 3LL tumor cells (p < 0.01). CONCLUSIONS DCs engineered to secrete Flt3L may offer a new strategy in DC-based cancer vaccines.
Collapse
Affiliation(s)
- Yongqing Liu
- Departments of Microbiology and Pathology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada S7N 0W0
| | | | | | | | | |
Collapse
|
10
|
Pabst R, Lührmann A, Steinmetz I, Tschernig T. A single intratracheal dose of the growth factor Fms-like tyrosine kinase receptor-3 ligand induces a rapid differential increase of dendritic cells and lymphocyte subsets in lung tissue and bronchoalveolar lavage, resulting in an increased local antibody production. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2003; 171:325-30. [PMID: 12817014 DOI: 10.4049/jimmunol.171.1.325] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Repetitive doses of the growth factor Fms-like tyrosine kinase receptor-3 ligand (Flt3L) have resulted in increased numbers of dendritic cells (DC) in various organs, and the effect on protective or tolerogeneic responses in the gut wall has been documented in the literature. In this study, for the first time, Flt3L was locally applied in the trachea of rats using a single dose only. A dose-dependent increase not only of DC, but also of T lymphocytes (CD4(+) and CD8(+)), was seen with a maximum on day 3. The effects on the cells in the lung interstitium and the bronchoalveolar space showed some differences. The use of tetanus toxoid as a model Ag applied intratracheally after the local Flt3L stimulation resulted in increased levels of specific IgA and IgG in the lung. Thus, this novel approach of locally stimulating APCs by topical application of a DC growth factor before applying the Ag offers a new vaccination strategy.
Collapse
Affiliation(s)
- Reinhard Pabst
- Department of Functional and Applied Anatomy, Medical School of Hannover, Hannover, Germany.
| | | | | | | |
Collapse
|
11
|
Vasu C, Dogan RNE, Holterman MJ, Prabhakar BS. Selective induction of dendritic cells using granulocyte macrophage-colony stimulating factor, but not fms-like tyrosine kinase receptor 3-ligand, activates thyroglobulin-specific CD4+/CD25+ T cells and suppresses experimental autoimmune thyroiditis. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2003; 170:5511-22. [PMID: 12759428 DOI: 10.4049/jimmunol.170.11.5511] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Fms-like tyrosine kinase receptor 3-ligand (Flt3-L) and GM-CSF cause expansion of different subsets of dendritic cells and skew the immune response toward predominantly Th1 and Th2 type, respectively. In the present study, we investigated their effects on experimental autoimmune thyroiditis in CBA/J mice. Relative to mouse thyroglobulin (mTg) immunized controls, mTg-immunized mice treated with Flt3-L showed more severe thyroiditis characterized by enhanced lymphocytic infiltration of the thyroid, and IFN-gamma and IL-2 production. In contrast, mice treated with GM-CSF, either before or after immunization with mTg, showed suppressed T cell response to mTg and failed to develop thyroiditis. Lymphocytes from these mice, upon activation with mTg in vitro, produced higher levels of IL-4 and IL-10. Additionally, GM-CSF-treated mice showed an increase in the frequency of CD4(+)/CD25(+) T cells, which suppressed the mTg-specific T cell response. Neutralization of IL-10, but not IL-4, or depletion of CD4(+)/CD25(+) cells resulted in increased mTg-specific in vitro T cell proliferation suggesting that IL-10 produced by the Ag-specific CD4(+)/CD25(+) regulatory T cells might be critical for disease suppression. These results indicate that skewing immune response toward Th2, through selective activation of dendritic cells using GM-CSF, may have therapeutic potential in Th1 dominant autoimmune diseases including Hashimoto's thyroiditis.
Collapse
|
12
|
Kim EM, Sivanandham M, Stavropoulos CI, Wallack MK. Adjuvant effect of a Flt3 ligand (FL) gene-transduced xenogeneic cell line in a murine colon cancer model. J Surg Res 2002; 108:148-56. [PMID: 12443727 DOI: 10.1006/jsre.2002.6540] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
BACKGROUND Flt3 Ligand (FL) has been shown to elicit antitumor responses induced by tumor antigen stimulation. Allogeneic and xenogeneic cell lines transduced with cytokine genes may be used to augment the antitumor efficacy of tumor antigens. OBJECTIVES The objective was to evaluate the augmentation of tumor lysate-induced immunity by a more clinically applicable FL gene-transduced xenogeneic cell line in combination with interleukin-2 (IL-2) in a CC-36 murine colon cancer model. METHODS Human 143B osteosarcoma tumor cells were transduced with full-length FL cDNA (143B-FL). Secretion of FL from 143B-FL was analyzed in vivo in normal BALB/c mice transplanted with 143B-FL, and expansion of dendritic cells (DC) was also analyzed in the same mice by flow cytometry. Eight-week-old, male BALB/c mice were used in a prophylactic vaccination protocol utilizing tumor lysate (CLy), 143B-FL, and soluble IL-2. Prophylactic group designations (n = 10/group) were as follows: ten million 143B-FL cells (alone, with tumor lysate, or with tumor lysate and IL-2), IL-2 with tumor lysate, IL-2 alone, or a no treatment control. The tumor lysate (200 microg of protein) and IL-2 (100,000 IU) injections were administered intraperitoneally. Mice were challenged subcutaneously with 10(3) CC-36 tumor cells. Tumor protection and tumor burden (TB), as mean tumor diameter, were determined. Peripheral blood lymphocytes (PBLs) from the 143B-FL + IL-2 + tumor lysate vaccinated group were analyzed for cytolytic activity in 4-h chromium release assays. In addition, plasma cytokine concentrations of interleukin-12 (IL-12) and interferon gamma (IFN-gamma) were assessed by ELISA. Student's t tests were used for all statistical comparisons. RESULTS In vivo expression of FL was observed 24 h following the inoculation of 143B-FL, and a four fold increase in DCs was observed in the peripheral blood of these mice. Mice immunized with a combination of 143B-FL, tumor lysate and IL-2 showed statistically significant protection against tumor development (10%) for 100 days after tumor challenge; incidences in other groups ranged from 40 to 100% (P < 0.05). Moreover, this immunization protocol produced the lowest TB at 3- and 6-week time points (0, 1.6 mm) when compared to all other groups (TB between 7.2 and 15.9 mm) (P < 0.05). In addition, PBLs from vaccinated mice showed increased cytolytic activity against CC-36 target cells. This corresponded to increased levels of IL-12 and IFN-g in the plasma of mice following vaccination. CONCLUSIONS These data suggest that FL gene-transduced xenogeneic tumor cells may augment the immunity induced by tumor antigens and systemic IL-2 through the activation of dendritic cells and T-cell-mediated mechanisms.
Collapse
Affiliation(s)
- Eugene M Kim
- Department of Surgery, Saint Vincents Hospital & Medical Center of New York, New York Medical College, 10011, USA
| | | | | | | |
Collapse
|