Biomedical subjects

Guido Forni

Publications and source records attributed to Guido Forni.

At least 37 records · Page 2Linked to original sources

PubMed2005

Xenogeneic immunization in mice using HER2 DNA delivered by an adenoviral vector.

The protective efficacy of xenogeneic vaccination with DNA encoding the HER2 oncogene was evaluated in BALB/c mice transgenic for the transforming form of the neu oncogene, which spontaneously develops carcinomas in all mammary glands. Intramuscular injection of either plasmid DNA followed by electrical stimulation (pVIJ-HER2 with ES) or an adenoviral vector (Ad5-HER2), both expressing the HER2 oncogene, was tested. Immunization using pVIJ-HER2 with ES elicited a cell-mediated response that was much lower than that elicited by the immunization with Ad5-HER2, as measured by the frequency of IFN-gamma-secreting spleen cells. The dominant T-cell epitope of the HER2 protein product (p185) in the BALB/c (H-2(d)) genetic background was identified. While the T-cell response elicited was only partially crossreactive with the corresponding rat epitopes because of sequence variations (89% similarity), a cytotoxic T-lymphocyte activity against the rat immunodominant epitope was also evident. The Ad5-HER2 vaccination induced also antibodies against p185, which crossreacted with the rat protein homolog. Both T- and B-cell responses slowly declined with time. Vaccination with Ad5-HER2 at 6 and 9 weeks of age delayed incidence and reduced multiplicity of tumors in neu transgenic mice.

Adenoviridae↗

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↗

PubMed2005

Gene expression analysis of immune-mediated arrest of tumorigenesis in a transgenic mouse model of HER-2/neu-positive basal-like mammary carcinoma.

We previously showed that a vaccine combining interleukin 12 and allogeneic p185(neu)-positive mammary carcinoma cells completely prevented multifocal mammary carcinogenesis in HER-2/neu transgenic mice. To identify the molecular events responsible for effective tumor prevention and to define the tumor gene expression signature, we used microarrays to analyze the expression profile of mammary tissue of untreated transgenic mice and of vaccine-treated, tumor-free mice at different time points. Mammary tissue from vaccinated mice displayed a gene expression profile different from that of untreated, tumor-bearing mice but similar to that of normal/hyperplastic mammary gland. Comparison of treated and untreated mice at 15 weeks of age revealed up-regulation of genes encoding antibodies, chemokines, gamma-interferon-induced genes and inflammatory molecules, and down-regulation of early genes induced by tumor development. The gene expression signature of HER-2/neu-transformed tumor cells showed modulation of genes promoting proliferation, angiogenesis, migration, invasion, and metastasis and inhibiting apoptosis and immune response. Meta-analysis of microarray data on human breast cancer showed that the signature of tumors arising in murine HER-2/neu transgenic model correctly classified human HER-2/neu-expressing tumors and normal breast tissue. Moreover murine and human HER-2/neu-positive tumors share the signature of basal-like breast cancers. This gene expression analysis reveals the immune events associated with prevention of tumor development and shows that HER-2/neu transgenic mice represent a good model of a poor-prognosis group of human breast tumors.

Animals↗

PubMed2005

Immunotherapy and immunoprevention of cancer: where do we stand?

Although evolution has shaped the immune system to control microbial invasions, this does not necessarily mean that the immune system can not be triggered to eliminate tumour cells. The exploitation of the terrific potential of the immune system to recognise cell alterations and to selectively destroy large populations of neoplastic cells is a possibility made even more attractive by the advances in our understanding of the immune mechanisms and our ability to manipulate them. This review summarises the state of the different immunotherapy strategies available or in development today, and examines the future developments that hold out the promise of an effective control of cancer growth.

Animals↗

PubMed2005

Cancer immunoprevention.

Immunoprevention is a fresh approach to cancer prevention based on the stimulation of the immune system before tumor onset. Immunoprevention was effective in various models of carcinogen-induced or autochthonous tumor progression. Vaccines made of cells or DNA plasmids combined with appropriate adjuvants completely blocked mammary carcinogenesis in HER-2/neu transgenic mice. At variance with cancer immunotherapy, the mediators of immunoprevention are antibodies and T-cell-derived cytokines, rather than cytotoxic T-cells. Immunopreventive approaches and chemoprevention with tamoxifen or cyclooxygenase-2 inhibitors can be combined advantageously. The success obtained in preclinical studies suggests that cancer immunoprevention should progress to clinical testing.

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

Vaccination by genetically modified dendritic cells expressing a truncated neu oncogene prevents development of breast cancer in transgenic mice.

Dendritic cells (DCs) are powerful antigen-presenting cells that process antigens and present peptide epitopes in the context of the major histocompatibility complex molecules to generate immune responses. DCs are being studied as potential anticancer vaccines because of their ability to present antigens to naive T cells and to stimulate the expansion of antigen-specific T-cell populations. We investigated an antitumor vaccination using DCs modified by transfer of a nonsignaling neu oncogene, a homologue of human HER-2/neu, in a transgenic model of breast cancer. BALB-neuT mice develop breast cancers as a consequence of mammary gland-specific expression of an activated neu oncogene. We vaccinated BALB-neuT mice with bone marrow-derived DCs transduced with Ad.Neu, a recombinant adenovirus expressing a truncated neu oncoprotein. The vaccine stimulated the production of specific anti-neu antibodies, enhanced interferon-gamma expression by T cells, and prevented or delayed the onset of mammary carcinomas in the mice. Over 65% of vaccinated mice remained tumor free at 28 weeks of age, whereas all of the mice in the control groups developed tumors. When challenged with a neu-expressing breast cancer cell line, vaccinated tumor-free animals had delayed tumor growth compared with controls. The antitumor effect of the vaccine was specific for expression of neu. Studies showed that CD4+ T cells were required in order to generate antitumor immunity. Importantly, the effectiveness of the vaccine was not diminished by preexisting immunity to adenovirus, whereas the protection afforded by vaccination that used direct injection of Ad.Neu was markedly reduced in mice with anti-adenovirus antibody titers. DCs modified by recombinant adenoviruses expressing tumor-associated antigens may provide an effective antitumor vaccination strategy.

Adenoviridae↗

PubMed2004

Oral lactoferrin inhibits growth of established tumors and potentiates conventional chemotherapy.

In this work, we investigated the anticancer activity of orally administered recombinant human lactoferrin (rhLF) alone and in combination with chemotherapy in tumor-bearing mice. rhLF inhibited the growth of squamous cell carcinoma (O12) tumors in T cell-immunocompromised nu/nu mice by 80% when administered at 1,000 mg/kg (2.9 g/m2) by oral gavage twice daily for 8 days (p < 0.001). Similar activity was observed in syngeneic, immunocompetent BALB/c mice, where orally administered rhLF (1,000 mg/kg, 2.9 g/m2 once daily) halted the growth of mammary adenocarcinoma TUBO. Oral rhLF (200 mg/kg, 0.57 g/m2) was also used alone and in combination with cis-platinum (5 mg/kg) to treat head-and-neck squamous cell carcinoma in a syngeneic murine model. Monotherapy with oral rhLF or cis-platinum caused 61% or 66% tumor growth inhibition over placebo, respectively. Mice receiving both therapies showed 79% growth inhibition, a statistically significant improvement over each drug alone. We then demonstrated that administration of oral rhLF (300 mg/kg, 0.86 g/m2) to tumor-bearing or naive mice resulted in (i) significantly increased production of IL-18 in the intestinal tract, (ii) systemic NK cell activation and (iii) circulating CD8+ T-cell expansion. These data suggest that oral rhLF is an immunomodulatory agent active against cancer as a single agent and in combination chemotherapy, exerting its systemic effect through stimulation of IL-18 and other cytokines in the gut enterocytes. rhLF has been administered orally to 211 people without a single serious drug-related adverse event. Thus, rhLF shows promise as a safe and well-tolerated novel immunomodulatory anticancer agent.

Administration, Oral↗

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

Towards a long-lasting immune prevention of HER2 mammary carcinomas: directions from transgenic mice.

Several theoretical and practical issues differentiate immune prevention from tumor immune therapy. The latter seeks to induce a rapid reaction against a life-threatening tumor, whereas prevention is dictated by the need to maintain constant surveillance of a situation in which an event is foreseen, but may not occur. The time frame of successful prevention is therefore long and often lifelong. Time itself is thus a key factor in the elaboration of vaccines to prevent tumor growth and its great length in preventive management poses new immunological problems that cannot be studied in short-term vaccination-challenge experiments. Many recent data indicate that HER2 receptor displays several features of an ideal tumor associated antigen and that an immune response can significantly alter HER2 tumor progression. We are thus using vaccination in the immune prevention and cure of carcinomas in HER2 transgenic mice in the search for a rationale for the application of preventive and curative vaccination for patients with HER2/ErbB-2 neoplastic lesions or at risk of recurrence after successful surgery. The design of effective immunopreventive approaches that can be translated to human situations is an important issue. A molecularly defined, effective and validated anti HER2 vaccine and the definition of immune mechanisms leading to the inhibition of HER2-driven neoplastic proliferation may provide a new way of treating these patients.

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

Immunological inhibition of carcinogenesis.

The combination of new information provided by fundamental immunology, along with the refinement of genetic engineering techniques has given scientists the capacity to produce vaccines able to inhibit the growth of most if not every transplantable tumor. However, when faced with already established tumors, vaccines fail to afford any significant protection. Many studies are underway which seek to overcome this gloomy situation. However, another possibility is to follow the indications provided by a large quantity of experimental data and to evaluate the possibility of using immunotherapy to prevent the initial stages of tumor growth. Is it possible to prevent an autologous tumor by means of a vaccination performed before tumor onset? Could antitumor vaccines be a new form of preventive medicine in the wake of Jenner, Pasteur, and other pioneers? In this paper it is our intention to review the results obtained by our laboratory in the attempt to use natural and adaptive immunity in the control of carcinogenesis. Natural immunity boosted by IL-12 and IL-2 significantly hampers the progression of mammary lesions occurring in HER-2/neu transgenic mice genetically predestined to develop lethal mammary carcinomas. Specific immunity elicited by DNA vaccination provides a much stronger inhibition of the development of mammary lesions, and a significant number of transgenic mice are tumor free at 1 year of age. These experimental data suggest the possibility of using immunity as a means of controlling preneoplastic lesions and protecting healthy persons at risk of developing cancer.

Animals↗

PubMed2004

Concordant morphologic and gene expression data show that a vaccine halts HER-2/neu preneoplastic lesions.

While much experimental data shows that vaccination efficiently inhibits a subsequent challenge by a transplantable tumor, its ability to inhibit the progress of autochthonous preneoplastic lesions is virtually unknown. In this article, we show that a combined DNA and cell vaccine persistently inhibits such lesions in a murine HER-2/neu mammary carcinogenesis model. At 10 weeks of age, all of the ten mammary gland samples from HER-2/neu-transgenic mice displayed foci of hyperplasia that progressed to invasive tumors. Vaccination with plasmids coding for the transmembrane and extracellular domain of rat p185neu followed by a boost with rp185neu+ allogeneic cells secreting IFN-gamma kept 48% of mice tumor free. At 22 weeks, their mammary glands were indistinguishable from those of 10-week-old untreated mice. Furthermore, the transcription patterns of the two sets of glands coincided. Of the 12,000 genes analyzed, 17 were differentially expressed and related to the antibody response. The use of B cell knockout mice as well as the concordance of morphologic and gene expression data demonstrated that the Ab response is the main mechanism facilitating tumor growth arrest. This finding suggests that a new way can be found to secure the immunologic control of the progression of HER-2/neu preneoplastic lesions.

Animals↗

PubMed2004

Immunobiology of her-2/neu transgenic mice.

Development of the mammary gland is controlled by hormones and many other growth factors. Hyperplasia and neoplasia are thus a likely consequence of alterations in their number and type, or the number and function of their receptors. p185neu, a member of the epidermal growth factor family, is coded by the ErbB-2 oncogene. It is expressed in the normal human breast, but overexpressed and associated with a poor prognosis in 15-30% of breast tumours. Employment of ErbB-2 sequences as vaccinal antigens to induce an immune rejection of such tumours is being investigated in several transgenic animal models. One of the most aggressive models of mammary p185neu-dependent carcinogenesis is that of BALB-neuT mice, which are transgenic for the rat transforming Her-2/neu oncogene (a homologue of the human ErbB-2 oncogene). The progression of their early neoplastic lesions can be prevented with both cellular and DNA vaccines coadjuvated by antiangiogenic and immunostimulatory molecules. This suggests that induction of a specific immune reaction against a tumor target antigen may provide a way of preventing the onset of tumours in subjects with a high genetic risk of developing cancer.

Animals↗

PubMed2004

Proinflammatory cytokines, immune response and tumour progression.

Tumour cells naturally secrete proinflammatory cytokines and chemokines to interact with the microenvironment and regulate neoangiogenesis. The repertoire of factors thus produced shapes tumour progression. However, experiments in the mouse have shown that injection of a low pharmacological dose of a proinflammatory cytokine or chemokine into the microenvironment increases the inflammatory reaction so enormously that locally activated leukocytes inhibit or eradicate the tumour. Massive shrinkage of recurrent head and neck squamous cell carcinomas (SCC) and prevention of recurrences after surgical removal of a primary SCC follow perilymphatic administration of low doses of interleukin (IL)2, while low daily doses of IL12 markedly delay carcinogenesis in transgenic mice predestined to die of mammary carcinomas and keep them tumour-free for long periods. The reaction elicited by proinflammatory cytokines evidently has a great potential in tumour control.

Animals↗

PubMed2003

CCL16/LEC powerfully triggers effector and antigen-presenting functions of macrophages and enhances T cell cytotoxicity.

The human CC chemokine CCL16, a liver-expressed chemokine, enhances the killing activity of mouse peritoneal macrophages by triggering their expression of tumor necrosis factor alpha (TNF-alpha) and Fas ligand. Macrophages also respond to CCL16 by enhancing their production of monocyte chemoattractant protein-1, regulated on activation, normal T cells expressed and secreted chemokines, and interleukin (IL)-1 beta, TNF-alpha, and IL-12. The effect of CCL16 is almost as strong as that of lipopolysaccharide and interferon-gamma, two of the best macrophage activators. Moreover, CCL16-activated macrophages overexpress membrane CD80, CD86, and CD40 costimulatory molecules and extensively phagocytose tumor cell debris. On exposure to such debris, they activate a strong, tumor-specific, cytolytic response in virgin T cells. Furthermore, cytolytic T cells generated in the presence of CCL16 display a higher cytotoxicity and activate caspase-8 in tumor target cells. This ability to activate caspase-8 depends on their overexpression of TNF-alpha and Fas ligand induced by CCL16. These data reveal a new function for CCL16 in the immune-response scenario. CCL16 significantly enhances the effector and the antigen-presenting function of macrophages and augments T cell lytic activity.

Animals↗

PubMed2003

Alpha-galactosylceramide (KRN7000) suppression of chemical- and oncogene-dependent carcinogenesis.

Recent studies have revealed significant efficacy of the marine sponge glycolipid, alpha-galactosylceramide (alpha-GalCer), in treatment of experimental metastatic cancers, infections, and autoimmune diseases. However, the capacity of alpha-GalCer to prevent tumor development had never, to our knowledge, been evaluated in mouse models of chemical- and oncogene-dependent carcinogenesis. In this study, we demonstrate that long-term administration of soluble alpha-GalCer, spanning the time of tumor initiation, inhibits primary tumor formation in three different models: methylcholanthrene-induced sarcomas, mammary carcinomas in Her-2/neu transgenic mice, and spontaneous sarcomas in p53-/- mice. Weekly treatment of mice with alpha-GalCer maintained lymphoid tissue natural killer cell and T cell activation and elevated serum IFN-gamma and IL-4 concentrations. Consistent with the antimetastatic activity of alpha-GalCer, prevention of methylcholanthrene-induced sarcoma was IFN-gammaand tumor necrosis factor-related apoptosis-inducing ligand dependent, but not perforin-dependent. Taken together, our results demonstrate that NK1.1+alphabetaTCR+ cell-based immune therapy can inhibit primary tumorigenesis.

Animals↗

PubMed2003

Prevention of HER-2/neu transgenic mammary carcinoma by tamoxifen plus interleukin 12.

FVB-NeuN (N#202) female mice transgenic for the HER-2/neu protooncogene driven by the murine mammary tumor virus (MMTV) promoter develop mammary carcinomas with a progression from focal atypical hyperplasia to in situ carcinoma and to invasive carcinoma that closely resembles that of human neoplasia. Here we report that the combination of tamoxifen plus interleukin 12 (IL-12) results in a very effective prevention of mammary carcinogenesis, significantly higher than those obtained with either tamoxifen or IL-12 alone. At 1 year of age, 20% of control mice resulted tumor-free, whereas 80% of mice receiving the combined treatment were tumor-free. At 2 years of age, less than 5% of control mice were tumor-free, as opposed to 70% of mice treated with tamoxifen plus IL-12. The combined treatment inhibited mammary carcinogenesis mainly through a reduction in the number of mammary cells at risk of progression, a reduction in estrogen receptors (ERs) expression and a reduction in the angiogenic support to mammary development, likely due to cross-talk between tamoxifen and interferon-gamma (IFN-gamma) (the main downstream mediator elicited in vivo by IL-12). The addition of IL-12 to the tamoxifen treatment more than doubled mouse lifetime and did not exacerbate known side effects of tamoxifen.

Adjuvants, Immunologic↗