Biomedical subjects

Emma Di Carlo

Publications and source records attributed to Emma Di Carlo.

At least 19 recordsLinked to original sources

PubMed2006

Timely DNA vaccine combined with systemic IL-12 prevents parotid carcinomas before a dominant-negative p53 makes their growth independent of HER-2/neu expression.

Double transgenic mice overexpressing the transforming rat HER-2/neu oncogene and the mutated p53, with both dominant-negative and a gain-of-function properties, display early aggressive and metastasizing parotid tumors. Multiple acinar and ductal hyperplasia foci overexpressing the HER-2/neu gene product are evident at wk 5 and progress to poorly differentiated carcinoma by wk 7. Mice die before wk 18 with invasive carcinomas and multiple metastases that no longer express HER-2/neu. A combination of repeated electroporations of plasmids coding for the extracellular and transmembrane domains of the rat HER-2/neu receptor with systemic IL-12 administrations started when the parotids that present diffuse hyperplasia protected all female and 50% of the male mice until the close of the experiment at wk 40. This combined treatment began when multifocal in situ carcinomas that were already present cured 33% of the females and 25% of the males. The most prominent immunologic features associated with the antitumor protection were the production of high titers of anti-HER-2/neu Abs and the nonappearance of cell-mediated cytotoxic reactivity. In conclusion, anti-HER-2/neu vaccination combined with systemic IL-12 control parotid carcinomas as far as p53 mutation makes their growth independent of HER-2/neu expression.

3T3 Cells↗

PubMed2006

Methylation of the IL-12Rbeta2 gene as novel tumor escape mechanism for pediatric B-acute lymphoblastic leukemia cells.

Previous studies have shown that the interleukin-12 receptor beta2 (IL-12Rbeta2) gene is expressed in normal naive, germinal center and memory B cells but not in their malignant counterparts. The aim of this study was to investigate (i) whether the IL-12Rbeta2 gene is silenced in B-cell acute lymphoblastic leukemia (B-ALL) cells, and (ii) what the functional implications of such silencing for tumor growth are. Here, we show that although mature B cells expressed both chains of the IL-12R, normal pro-B and pre-B cells failed to express the IL-12Rbeta2 chain. Similarly, primary tumor cells from pediatric pro-B, early pre-B, and pre-B ALL (30 cases) did not express the IL-12Rbeta2 chain. IL-12Rbeta2 gene silencing in B-ALL was found to depend on methylation of a CpG island in exon 1. Such methylation was not detected in normal early B cells that when differentiated into mature B cells expressed the IL-12Rbeta2 gene. Detection of IL-12Rbeta2 mRNA and protein in the tumorigenic 697 pre-B-ALL cell line allowed to perform functional experiments in severe combined immunodeficient/nonobese diabetic mice receiving 697 cells with or without human recombinant IL-12 (hrIL-12). hrIL-12 administration reduced tumor growth and metastasis through antiproliferative and proapoptotic rather than antiangiogenic, activities. In conclusion, epigenetic silencing of the IL-12Rbeta2 gene represents a novel mechanism of tumor escape for B-ALL cells.

Animals↗

PubMed2006

CD25+ regulatory T cell depletion augments immunotherapy of micrometastases by an IL-21-secreting cellular vaccine.

IL-21 is an IL-2-like cytokine, signaling through a specific IL-21R and the IL-2R gamma-chain. Because the TS/A mammary adenocarcinoma cells genetically modified to secrete IL-21 (TS/A-IL-21) are strongly immunogenic in syngeneic mice, we analyzed their application as vaccine. In mice bearing TS/A-parental cell (pc) micrometastases, vaccination with irradiated TS/A-IL-21 cells significantly increased the animal life span, but cured only 17% of mice. Spleen cells from cured mice developed CTL activity and produced IFN-gamma in response to stimulation by the AH1 epitope of the gp70env Ag of TS/A-pc. We tested whether the low therapeutic outcome might be due to CD4+CD25+ regulatory T cells (Treg) present in TS/A-pc tumors and draining lymph nodes and whether IL-21 had any effect on these cells. Indeed, CD4+CD25+ cells suppressed IFN-gamma production by splenocytes from immune mice in response to stimulation by the AH1 peptide. Low concentrations of IL-21 (10 ng/ml) failed to reverse the inhibitory activity of CD4+CD25+ cells in an allogeneic MLR, whereas 60 ng/ml rIL-21 partially restored responder T cell proliferation. IL-21R expression on CD25- lymphocytes suggested that IL-21 could be more effective in mice depleted of CD25+ cells. Depletion of Treg cells by a single dose of anti-CD25 mAb combined with TS/A-IL-21 cell vaccine cured >70% of mice bearing micrometastases, whereas anti-CD25 mAb treatment alone had no effect. Successful combined immunotherapy required NK cells, CD8+ T cells, and IFN-gamma. In conclusion, immunotherapy of micrometastases by an IL-21-based cellular vaccine is strongly potentiated by CD25+ cell depletion.

Adjuvants, Immunologic↗

PubMed2006

Targeting tumor-related immunosuppression for cancer immunotherapy.

Tumors produce several factors, such as Prostaglandins (PGs), Interleukin (IL)-10, Vascular Endothelial Growth Factor (VEGF) and Transforming Growth Factor (TGF)-beta, which may directly or indirectly inhibit the immune response and may hamper immunotherapy. Furthermore, cells of innate or adaptive immunity, recruited by tumor-derived factors, may contribute in immunosuppression. Regulatory T (Treg) cells such as the "naturally occurring" CD4(+)/CD25(+) Treg and the IL-10-induced Tr1 cells are major players in this arena. Paradoxically Treg cells are stimulated by IL-2, which is used in tumor immunotherapy. Treg cells suppress T cell responses through soluble factors or by contact-dependent mechanisms, such as the Cytotoxic T Lymphocyte Antigen (CTLA)-4-mediated induction of Indoleamine 2,3-Dioxygenase (IDO) in dendritic cells (DC). IDO inhibits T cell responses by depleting Tryptophan and producing Kynurenine, which is toxic to lymphocytes. Macrophages, granulocytes or myeloid suppressor cells (MSC) suppress immunity by other enzymatic mechanisms, involving Arginase and Nitric Oxide Synthase (NOS). Subversion of tumor immunosuppression is required for successful immunotherapy. Attempts to block or eliminate Treg cells have been made by the use of chemotherapy, anti-CD25 or anti-CTLA-4 antibodies, IL-2-toxin chimeric proteins or Glucocorticoid-induced TNF-like Receptor (GITR) and CD134/OX-40 ligands. Tumor cells genetically modified to secrete IL-21 (an immune-stimulatory "IL-2-like" cytokine, which is not involved in immune regulation) cured experimental metastases in combination with anti-CD25 monoclonal antibodies (mAbs). Also strategies aimed at blocking enzyme-based immune-suppressive mechanisms are suitable, as suggested by experimental evidences in mouse tumor models.

Animals↗

PubMed2005

Lack of Il12rb2 signaling predisposes to spontaneous autoimmunity and malignancy.

The interleukin-12 receptor beta2 (Il12rb2) gene is silenced in tumor cells from different human B-cell malignancies as opposed to their normal counterparts. It was hypothesized that this silencing allows neoplastic B cells to escape the control exerted by IL-12 on their growth. The aim of this study was to investigate whether targeted inactivation of the Il12rb2 gene in mice resulted into increased susceptibility to spontaneous tumor formation and immunopathology. Il12rb2 gene-deficient animals developed in the first year of life immune-complex mesangial glomerulonephritis with serum antinuclear antibodies. In older animals, multiorgan lymphoid infiltrates with features of vasculitis and Sjögren syndrome were detected in association with systemic B- and T-cell activation. In half of aged animals, lymph node plasmacytoma or lung carcinoma was observed. A mechanism for spontaneous development of autoimmune pathology and B-cell tumors is suggested by a strong IL-6 up-regulation detected in splenocytes and lymphoid infiltrates associated with oligoclonal B-cell expansion. The emergence of lung tumors may likely be attributed to an interferon-gamma (IFN-gamma) deficiency secondary to lack of IL-12 signaling. The development of autoimmunity, lymphoproliferation, and B-cell tumors in Il12rb2 knockout (KO) mice suggests that IL-12 functions physiologically to restrain aberrant B-cell activation.

Animals↗

PubMed2005

Mammary carcinoma provides highly tumourigenic and invasive reactive stromal cells.

The progression of a lesion to a carcinoma is dependent on the engagement of 'reactive stroma' that provides structural and vascular support for tumour growth and also leads to tissue reorganization and invasiveness. The composition of reactive stroma closely resembles that of granulation tissue, and myofibroblasts are thought to play a critical role in driving the stromal reaction of invasive tumours as well as of physiological wound repair. In the present work, we established a myofibroblast-like cell line, named A17, from a mouse mammary carcinoma model in which tumourigenesis is triggered in a single step by the overexpression of HER-2/neu transgene in the epithelial compartment of mammary glands. We showed that although they derived from a tumour of epithelial origin and did not express HER-2/neu transgene, their subcutaneous injection into the backs of syngeneic mice gave rise to sarcomatoid tumours which expressed alpha-smooth muscle actin at the invasive edge. The expression of cytokeratin 14 suggested a myoepithelial origin but immunophenotypical profile, invasive and neoangiogenic potential of A17 cells and tumours showed many similarities with the reactive stroma that occurs in wound repair and in cancerogenesis. Our results suggest that epithelial tumours have the potential to develop highly tumourigenic and invasive reactive stromal cells and our cell line represents a novel, effective model for studying epithelial-stromal interaction and the role of myofibroblasts in tumour development.

Animals↗

PubMed2005

Cure of mammary carcinomas in Her-2 transgenic mice through sequential stimulation of innate (neoadjuvant interleukin-12) and adaptive (DNA vaccine electroporation) immunity.

PURPOSE: Whereas neoadjuvant therapy is emerging as a treatment option in early primary breast cancer, no data are available on the use of antiangiogenic and immunomodulatory agents in a neoadjuvant setting. In a model of Her-2 spontaneous mammary cancer, we investigated the efficacy of neoadjuvant interleukin 12 (IL-12) followed by "immune-surgery" of the residual tumor. EXPERIMENTAL DESIGN: Female BALB/c mice transgenic for the rat Her-2 oncogene inexorably develop invasive carcinomas in all their mammary glands by the 23rd week of age. Mice with multifocal in situ carcinomas received four weekly i.p. injections of 100 ng IL-12 followed by a 3-week rest. This course was given four times. A few mice additionally received DNA plasmids encoding portions of the Her-2 receptor electroporated through transcutaneous electric pulses. RESULTS: The protection elicited by IL-12 in combination with two DNA vaccine electroporations kept 63% of mice tumor-free. Complete protection of all 1-year-old mice was achieved when IL-12-treated mice received four vaccine electroporations. Pathologic findings, in vitro tests, and the results from immunization of both IFN-gamma and immunoglobulin gene knockout transgenic mice and of adoptive transfer experiments all show that IL-12 augments the B- and T-cell response elicited by vaccination and slightly decreases the number of regulatory T cells. In addition, IL-12 strongly inhibits tumor angiogenesis. CONCLUSIONS: In Her-2 transgenic mice, IL-12 impairs tumor progression and triggers innate immunity so markedly that DNA vaccination becomes effective at late points in time when it is ineffective on its own.

Animals↗

PubMed2005

Inhibition of mammary carcinoma development in HER-2/neu transgenic mice through induction of autoimmunity by xenogeneic DNA vaccination.

Plasmid DNA vectors encoding the full-length (VR1012/HER-2-FL) or only the extracellular and transmembrane domains (VR1012/HER-2-ECD-TM) of human (h) HER-2/neu proto-oncogene were used to vaccinate HER-2/neu transgenic mice (N202) engineered to overexpress the rat (r) neu proto-oncogene product (r-p185(neu)). Both the full-length and the deleted vaccines were significantly (P = 0.0001 and P = 0.06, respectively) more active than the empty vector (VR1012/EV) in preventing and delaying HER-2/neu-driven mammary carcinogenesis. A low-level intratumoral infiltrate of dendritic cells, macrophages, CD8 T cells and polymorphonuclear granulocytes in association with low-level cytokine production was observed, which was not detected in tumors from control mice. Morphologic analyses showed that vaccination with VR1012/HER-2-FL or ECD-TM also efficiently hampered the development of terminal ductal lobular units (TDLU). Analyses of sera from vaccinated mice revealed high titers of antihuman HER-2/neu antibodies, which correlated with the delayed time of tumor onset (P = 0.002). These antibodies did not cross-react with r-p185(neu). Nontransgenic mice treated with the vaccines produced autoreactive antibodies targeting mouse (m)-p185(neu) and showed impaired function of the lactating mammary gland and accelerated involution of the gland after weaning. Together, these data indicate that xenogeneic DNA immunization breaks tolerance against the endogenous m-p185(neu), impairing the development of mammary TDLU in which m-p185(neu) expression is concentrated. The reduction in the number of TDLU decreases the number of glandular structures available for r-p185(neu)-dependent mammary carcinogenesis, resulting in a significant inhibition of mammary carcinoma development.

Amino Acid Sequence↗

PubMed2005

Immunological mechanisms elicited at the tumour site by lymphocyte activation gene-3 (LAG-3) versus IL-12: sharing a common Th1 anti-tumour immune pathway.

The experimentally induced TS/A murine mammary carcinoma is poorly immunogenic and mainly infiltrated by antigen-presenting cells (APCs), namely macrophages and immature dendritic cells (DCs). Human (h) and mouse (m) lymphocyte activation gene-3 (LAG-3 or CD233) is a physiological MHC class II ligand and powerful APC activator. A gene transfer approach has revealed its anti-tumour activity in this model: hLAG-3 was more effective than mLAG-3. To obtain a clearer picture of the immunoregulatory mechanisms associated with the rejection dynamics of h- and m-LAG-3 transfectants, immunohistochemistry and confocal microscopy analyses of TS/A-hLAG-3, TS/A-mLAG-3, and control TS/A-pc tumours were performed. The immune events elicited by mLAG-3 and m-interleukin (IL)-12 were also compared, since their rejection kinetics were quite similar, and LAG-3 enables IL-12 production by macrophages and DCs. Both the TS/A-h- and, to a lesser extent, the m-LAG-3 rejection areas were characterized by an impressive recruitment of APCs, granulocytes, NK cells, CD4+ T lymphocytes and CD8+ IFNgamma-expressing cells. In both cases, infiltration by APCs was accompanied by strong CD80 and CD86 expression and macrophage nitric oxide (NO) synthase up-regulation. Distinct expression of IL-12 and CXCL9 was also found, especially in the draining lymph nodes. T lymphocytes and CD86-expressing APCs were significantly prevalent in both the TS/A-h- and the m-LAG-3 compared with the TS/A-mIL-12 rejection area. Production of IFNgamma, TNFalpha and IL1beta, and chemokines, namely CXCL5, CXCL9, CXCL10, CXCL11, CCL5, and CCL2, by infiltrating leukocytes and signs of defective neovascularization were detected in tumours expressing h-LAG-3-, m-LAG-3-, and m-IL-12. However, IFNgamma, CCL2, and CCL5 production prevailed in the TS/A-hLAG-3 rejection area. Taken together, these results indicate that LAG-3 expression by engineered tumour cells efficiently promotes intra-tumoural recruitment, activation, and Th1 commitment of APCs, and leads to a wide intra-tumoural influx of non-specific and specific reactive cells, and the release of immunoregulatory and cytotoxic mediators. Many of LAG-3's anti-tumour activities are shared with IL-12.

Animals↗

PubMed2004

Immunological prevention of a multigene cancer syndrome.

Vaccines effectively prevent the onset of tumors in transgenic mice carrying activated oncogenes; however, human tumors are caused by combined alterations in oncogenes and oncosuppressor genes. We evaluated the impact of prophylactic vaccines in HER-2/neu transgenic, p53 wild-type/null mice that succumb to an aggressive cancer syndrome comprising mammary and salivary gland carcinomas and rhabdomyosarcoma. A vaccine made of allogeneic mammary carcinoma cells expressing HER-2/neu and interleukin 12 afforded long-term protection from tumor onset. Tumor prevention was mediated by T cell-derived cytokines, in particular gamma-interferon, and by anti-HER-2/neu antibodies. HER-2/neu expression was inhibited in target tissues of vaccinated mice, and somatic loss of the wild-type p53 allele did not occur. A highly effective vaccine against a single oncoprotein induced a powerful immune response that arrested multistep carcinogenesis in distinct target tissues.

Animals↗

PubMed2004

Immunoprevention of mammary carcinoma in HER-2/neu transgenic mice is IFN-gamma and B cell dependent.

A vaccine combining IL-12 and allogeneic mammary carcinoma cells expressing p185(neu) completely prevents tumor onset in HER-2/neu transgenic BALB/c mice (NeuT mice). The immune protection elicited was independent from CTL activity. We now formally prove that tumor prevention is mainly based on the production of anti-p185(neu) Abs. In the present studies, NeuT mice were crossed with knockout mice lacking IFN-gamma production (IFN-gamma(-/-)) or with B cell-deficient mice (microMT). Vaccination did not protect NeuT-IFN-gamma(-/-) mice, thus confirming a central role of IFN-gamma. The block of Ab production in NeuT-microMT mice was incomplete. About one third of NeuT-microMT mice failed to produce Abs and displayed a rapid tumor onset. By contrast, those NeuT-microMT mice that responded to the vaccine with a robust production of anti-p185(neu) Ab displayed a markedly delayed tumor onset. In these NeuT-microMT mice, the vaccine induced a lower level of IgG2a and IgG3 and a higher level of IgG2b than in NeuT mice. Moreover, NeuT-microMT mice failed to produce anti-MHC class I Abs in response to allogeneic H-2(q) molecules present in the cell vaccine. These findings show that inhibition of HER-2/neu carcinogenesis depends on cytokines and specific Abs, and that a highly effective vaccine can rescue Ab production even in B cell-deficient mice.

Animals↗

PubMed2004

Immunoprevention of HER-2/neu transgenic mammary carcinoma through an interleukin 12-engineered allogeneic cell vaccine.

This study evaluated the ability of cytokine-engineered allogeneic (H-2(q)) HER-2/neu-positive cells to prevent tumor development in mammary cancer-prone virgin female BALB/c (H-2(d)) mice transgenic for the transforming rat HER-2/neu oncogene (BALB-neuT mice). Repeated vaccinations with cells engineered to release interleukin (IL)-2, IL-12, IL-15, or IFN-gamma showed that IL-12-engineered cell vaccines had the most powerful immunopreventive activity, with >80% of 1-year-old BALB-neuT mice free of tumors. On the contrary all of the untreated mice and all of the mice vaccinated with IL-12-engineered cells lacking either HER-2/neu or allogeneic antigens developed mammary carcinomas within 22 or 33 weeks, respectively. Whole mount, histology, immunohistochemistry, and gene expression profile analysis showed that vaccination with IL-12-engineered cells maintained 26-week mammary glands free of neoplastic growth, with a gene expression profile that clustered with that of untreated preneoplastic glands. The IL-12-engineered cell vaccine elicited a high production of IFN-gamma and IL-4 and a strong anti-HER-2/neu antibody response. Immune protection was lost or markedly impaired in BALB-neuT mice lacking IFN-gamma or antibody production, respectively. The protection afforded by the IL-12-engineered cell vaccine was equal to that provided by the systemic administration of recombinant IL-12 in combination with HER-2/neu H-2(q) cell vaccine. However, IL-12-engineered cell vaccine induced much lower circulating IL-12 and IFN-gamma, and therefore lower potential side effects and systemic toxicity.

Animals↗

PubMed2004

Induced somatic inactivation of STAT3 in mice triggers the development of a fulminant form of enterocolitis.

We have generated mice in which the gene encoding the transcription factor STAT3 can be inactivated in multiple cell types by triggering the endogenous production of type I interferon. Gene inactivation is particularly effective in the liver and the adipose tissue, as well as in macrophages and gut epithelial cells. Upon induction of the mutation, mice develop a wasting syndrome culminating in an aggressive and fatal form of enterocolitis, limited to the large intestine, within 2-3 weeks after the treatment. The disease is characterised by massive infiltration of the gut mucosa by macrophages, granulocytes and CD4+ cells, increased expression of endothelial adhesion molecules and high production of the cytokines interleukin (IL)-6, IL-12, interferon-gamma and IL-10. IL-12 p40 plays a pivotal role in disease development as in vivo treatment with neutralising antibodies completely prevents its onset. Interestingly, oral treatment with wide spectrum antibiotics does not have any effect on either the onset or the development of colitis. Taken together, these data show that STAT3 plays a crucial role in the maintenance of intestinal homeostasis and possibly in mediating specialised cell functions in the intestinal epithelium.

Animals↗

PubMed2004

Electroporated DNA vaccine clears away multifocal mammary carcinomas in her-2/neu transgenic mice.

The transforming rat Her-2/neu oncogene embedded into the genome of virgin transgenic BALB/c mice (BALB-neuT) provokes the development of an invasive carcinoma in each of their 10 mammary glands. i.m. vaccination with DNA plasmids coding for the extracellular and transmembrane domains of the protein product of the Her-2/neu oncogene started when mice already display multifocal in situ carcinomas temporarily halts neoplastic progression, but all mice develop a tumor by week 43. By contrast, progressive clearance of neoplastic lesions and complete protection of all 1-year-old mice are achieved when the same plasmids are electroporated at 10-week intervals. Pathological findings, in vitro tests, and the results from the immunization of both IFN-gamma and immunoglobulin gene knockout BALB-neuT mice, and of adoptive transfer experiments, all suggest that tumor clearance rests on the combination of antibodies and IFN-gamma-releasing T cells. These findings show that an appropriate vaccine effectively inhibits the progression of multifocal preneoplastic lesions.

Animals↗

PubMed2004

CXCL1/macrophage inflammatory protein-2-induced angiogenesis in vivo is mediated by neutrophil-derived vascular endothelial growth factor-A.

The angiogenic activity of CXC-ELR(+) chemokines, including CXCL8/IL-8, CXCL1/macrophage inflammatory protein-2 (MIP-2), and CXCL1/growth-related oncogene-alpha in the Matrigel sponge angiogenesis assay in vivo, is strictly neutrophil dependent, as neutrophil depletion of the animals completely abrogates the angiogenic response. In this study, we demonstrate that mice deficient in the src family kinases, Hck and Fgr (hck(-/-)fgr(-/-)), are unable to develop an angiogenic response to CXCL1/MIP-2, although they respond normally to vascular endothelial growth factor-A (VEGF-A). Histological examination of the CXCL1/MIP-2-containing Matrigel implants isolated from wild-type or hck(-/-)fgr(-/-) mice showed the presence of an extensive neutrophil infiltrate, excluding a defective neutrophil recruitment into the Matrigel sponges. Accordingly, neutrophils from hck(-/-)fgr(-/-) mice normally migrated and released gelatinase B in response to CXCL1/MIP-2 in vitro, similarly to wild-type neutrophils. However, unlike wild-type neutrophils, those from hck(-/-)fgr(-/-) mice were completely unable to release VEGF-A upon stimulation with CXCL1/MIP-2. Furthermore, neutralizing anti-VEGF-A Abs abrogated the angiogenic response to CXCL1/MIP-2 in wild-type mice and CXCL1/MIP-2 induced angiogenesis in the chick embryo chorioallantoic membrane assay, indicating that neutrophil-derived VEGF-A is a major mediator of CXCL1/MIP-2-induced angiogenesis. Finally, in vitro kinase assays confirmed that CXCL1/MIP-2 activates Hck and Fgr in murine neutrophils. Taken together, these data demonstrate that CXCL1/MIP-2 leads to recruitment of neutrophils that, in turn, release biologically active VEGF-A, resulting in angiogenesis in vivo. Our observations delineate a novel mechanism by which CXCL1/MIP-2 induces neutrophil-dependent angiogenesis in vivo.

Angiogenesis Inducing Agents↗

PubMed2004

Intralesional injection of adenovirus encoding CC chemokine ligand 16 inhibits mammary tumor growth and prevents metastatic-induced death after surgical removal of the treated primary tumor.

The CC chemokine ligand (CCL)16 exerts chemotactic activity on human monocytes and lymphocytes. Although no murine homologous has been defined, the TSA mouse adenocarcinoma cells engineered to express human CCL16 are rapidly rejected by syngenic mice. An adenovirus encoding CCL16 (AdCCL16) was generated using a Cre-Lox-based system and was used to determine whether this chemokine might also block pre-existing tumors. Both recombinant and viral CCL16 showed in vitro chemotactic activity for murine CD4(+) and CD8(+) lymphocytes and dendritic cells (DC). AdCCL16, but not the control empty vector, when injected in established nodules significantly delayed tumor growth. Immunohistochemistry revealed accumulation of CD4(+) and CD8(+) T cells and DC in the treated tumors as well as in draining lymph nodes. DC from such lymph nodes stimulated IFN-gamma by a T cell clone specific for the known TSA tumor-associated Ag (TAA), suggesting the tumor origin of these cells. Lymphocytes from the same nodes showed specific CTL activity against TSA tumor cells and their immunodominant TAA peptide. Antitumor activity required CD4, CD8, and IFN-gamma production, as shown using subset-depleted and knockout mice. Despite the robust and rapid immune response triggered by intratumoral injection of AdCCL16, the lesions were not completely rejected; however, the same treatment given before surgical excision of primary lesions prevented metastatic spread and cured 63% of mice bearing the 4T1 mammary adenocarcinoma, which is perhaps the most compelling model of spontaneous metastasis.

Adenocarcinoma↗

PubMed2004

IL-21 induces tumor rejection by specific CTL and IFN-gamma-dependent CXC chemokines in syngeneic mice.

IL-21 is an immune-stimulatory four alpha helix cytokine produced by activated T cells. To study the in vivo antitumor activities of IL-21, TS/A murine mammary adenocarcinoma cells were genetically modified to secrete IL-21 (TS/A-IL-21). These cells developed small tumors that were subsequently rejected by 90% of s.c. injected syngeneic mice. Five days after injection, TS/A-IL-21 tumors showed numerous infiltrating granulocytes, NK cells, and to a lesser extent CD8(+) T cells, along with the expression of TNF-alpha, IFN-gamma, and endothelial adhesion molecules ICAM-1 and VCAM-1. At day 7, CD8(+) and CD4(+) T cells increased together with IFN-gamma, and the CXC chemokines IFN-gamma-inducible protein 10, monokine induced by IFN-gamma, and IFN-inducible T cell alpha-chemoattractant. The TS/A-IL-21 tumor displayed a disrupted vascular network with abortive sprouting and signs of endothelial cell damage. In vivo depletion experiments by specific Abs showed that rejection of TS/A-IL-21 cells required CD8(+) T lymphocytes and granulocytes. When injected in IFN-gamma-deficient mice, TS/A-IL-21 cells formed tumors that regressed in only 29% of animals, indicating a role for IFN-gamma in IL-21-mediated antitumor response, but also the existence of IFN-gamma-independent effects. Most immunocompetent mice rejecting TS/A-IL-21 cells developed protective immunity against TS/A-pc (75%) and against the antigenically related C26 colon carcinoma cells (61%), as indicated by rechallenge experiments. A specific CTL response against the gp70-env protein of an endogenous murine retrovirus coexpressed by TS/A and C26 cells was detected in mice rejecting TS/A-IL-21 cells. These data suggest that IL-21 represents a suitable adjuvant in inducing specific CTL responses.

Adenocarcinoma↗

PubMed2004

The IL-12Rbeta2 gene functions as a tumor suppressor in human B cell malignancies.

The IL-12Rbeta2 gene is expressed in human mature B cell subsets but not in transformed B cell lines. Silencing of this gene may be advantageous to neoplastic B cells. Our objective was to investigate the mechanism(s) and the functional consequence(s) of IL-12Rbeta2 gene silencing in primary B cell tumors and transformed B cell lines. Purified tumor cells from 41 patients with different chronic B cell lymphoproliferative disorders, representing the counterparts of the major mature human B cell subsets, tested negative for IL-12Rbeta2 gene expression. Hypermethylation of a CpG island in the noncoding exon 1 was associated with silencing of this gene in malignant B cells. Treatment with the DNA methyltransferase inhibitor 5-Aza-2'-deoxycytidine restored IL-12Rbeta2 mRNA expression in primary neoplastic B cells that underwent apoptosis following exposure to human recombinant IL-12 (hrIL-12). hrIL-12 inhibited proliferation and increased the apoptotic rate of IL-12Rbeta2-transfected B cell lines in vitro. Finally, hrIL-12 strongly reduced the tumorigenicity of IL-12Rbeta2-transfected Burkitt lymphoma RAJI cells in SCID-NOD mice through antiproliferative and proapoptotic effects, coupled with neoangiogenesis inhibition related to human IFN-gamma-independent induction of hMig/CXCL9. The IL-12Rbeta2 gene acts as tumor suppressor in chronic B cell malignancies, and IL-12 exerts direct antitumor effects on IL-12Rbeta2-expressing neoplastic B cells.

Animals↗