Biomedical subjects

Pier-Luigi Lollini

Publications and source records attributed to Pier-Luigi Lollini.

At least 19 recordsLinked to original sources

PubMed2006

Discovery of cancer vaccination protocols with a genetic algorithm driving an agent based simulator.

BACKGROUND: Immunological prevention of cancer has been obtained in HER-2/neu transgenic mice using a vaccine that combines 3 different immune stimuli (Triplex vaccine) that is repeatedly administered for the entire lifespan of the host (Chronic protocol). Biological experiments leave open the question of whether the Chronic protocol is indeed the minimal vaccination schedule affording 100% protection, or whether shorter protocols could be applied that would result in the same efficacy. A biological solution would require an enormous number of experiments, each lasting at least one year. Therefore we approached this problem by developing a simulator (SimTriplex) which describes the immune response activated by Triplex vaccine. This simulator, tested against in vivo experiments on HER-2/neu mice, reproduces all the vaccination protocols used in the in vivo experiments. The simulator should describe any vaccination protocol within the tested range. A possible solution to the former open question using a minimal search strategy based on a genetic algorithm is presented. This is the first step toward a more general approach of biological or clinical constraints for the search of an effective vaccination schedule. RESULTS: The results suggest that the Chronic protocol included a good number of redundant vaccine administrations, and that maximal protection could still be obtained with a number of vaccinations approximately 40% less than with the Chronic protocol. CONCLUSION: This approach may have important connotations with regard to translation of cancer immunopreventive approaches to human situations, in which it is desirable to minimize the number of vaccinations. We are currently setting up experiments in mice to test whether the actual effectiveness of the vaccination protocol agrees with the genetic algorithm.

Algorithms↗

PubMed2006

Endothelin-3 production by human rhabdomyosarcoma: a possible new marker with a paracrine role.

Several autocrine and paracrine growth factor circuits have been found in human rhabdomyosarcoma cells. In this study we show that endothelin-3 (ET-3), a vasoactive peptide, is produced by human rhabdomyosarcoma cell lines, whereas it is not expressed by human sarcoma cell lines of non-muscle origin. We did not find evidence of a significant autocrine loop; nevertheless ET-3 produced by rhabdomyosarcoma cells can act as a paracrine factor, since it promotes migration of endothelial cells. Moreover ET-3 is present in plasma of mice bearing xenografts of human rhabdomyosarcoma cells, and may be potential new marker of the human rhabdomyosarcoma to be studied further.

Biomarkers, Tumor↗

PubMed2006

CD99 acts as an oncosuppressor in osteosarcoma.

CD99 was recently reported to be under control of the osteoblast-specific transcription factor Cbfa1 (RUNX2) in osteoblasts, suggesting a role in the phato-physiology of these cells. No extensive information is available on the role(s) of this molecule in malignant phenotype, and osteosarcoma, in particular, has never been studied. We report that in 11 different cell lines and 17 clinical samples CD99 expression is either undetectable or very low. Being expressed in the normal counterpart, we tested the hypothesis that CD99 down-regulation may have a role in osteosarcoma development and progression. CD99-forced expression in two osteosarcoma cell lines significantly reduced resistance to anoikis, inhibited growth in anchorage independence as well as cell migration, and led to abrogation of tumorigenic and metastatic ability. Therefore, the molecule acts as a potent suppressor of malignancy in osteosarcoma. CD99 gene transfection induces caveolin-1 up-regulation and the two molecules were found to colocalize on the cell surface. Treatment with antisense oligonucleotides to caveolin-1 abrogates the effects of CD99 on migration. The findings point to an antioncogenic role for CD99 in osteosarcoma, likely through the regulation of caveolin-1 and inhibition of c-Src kinase activity.

12E7 Antigen↗

PubMed2006

Vaccines for tumour prevention.

Despite tremendous progress in basic and epidemiological research, effective prevention of most types of cancer is still lacking. Vaccine use in cancer therapy remains a promising but difficult prospect. However, new mouse models that recapitulate significant features of human cancer progression show that vaccines can keep precancerous lesions under control and might eventually be the spearhead of effective and reliable ways to prevent cancer.

Cancer Vaccines↗

PubMed2005

Targeting CD99 in association with doxorubicin: an effective combined treatment for Ewing's sarcoma.

CD99 is a 32kDa surface glycoprotein that is involved in the migration of leukocytes, cell-cell adhesion and apoptosis of T cells and Ewing's sarcoma (ES) cells, two cell types with a high level of CD99 expression. Engagement of the molecule induces a rapid death signal that appears to be related to the level of expression of this antigen. The rapid apoptosis induced by agonistic anti-CD99 monoclonal antibodies is of clinical interest in ES, a tumour for which no new drugs have been described as clearly effective in the last 10 years. In this study, we show that an anti-CD99 monoclonal antibody can be used to advantage in association with doxorubicin. Striking effectiveness was observed against local tumours and metastases. No remarkably toxic effects of anti-CD99 monoclonal antibody were found in bone marrow against blood precursors. These results provide the necessary rationale and support for a novel modality of therapeutic intervention, which may have application in the care of patients with ES.

12E7 Antigen↗

PubMed2005

An integrated approach of immunogenomics and bioinformatics to identify new Tumor Associated Antigens (TAA) for mammary cancer immunological prevention.

BACKGROUND: Neoplastic transformation is a multistep process in which distinct gene products of specific cell regulatory pathways are involved at each stage. Identification of overexpressed genes provides an unprecedented opportunity to address the immune system against antigens typical of defined stages of neoplastic transformation. HER-2/neu/ERBB2 (Her2) oncogene is a prototype of deregulated oncogenic protein kinase membrane receptors. Mice transgenic for rat Her2 (BALB-neuT mice) were studied to evaluate the stage in which vaccines can prevent the onset of Her2 driven mammary carcinomas. As Her2 is not overexpressed in all mammary carcinomas, definition of an additional set of tumor associated antigens (TAAs) expressed at defined stages by most breast carcinomas would allow a broader coverage of vaccination. To address this question, a meta-analysis was performed on two transcription profile studies to identify a set of new TAA targets to be used instead of or in conjunction with Her2. RESULTS: The five TAAs identified (Tes, Rcn2, Rnf4, Cradd, Galnt3) are those whose expression is linearly related to the tumor mass increase in BALB-neuT mammary glands. Moreover, they have a low expression in normal tissues and are generally expressed in human breast tumors, though at a lower level than Her2. CONCLUSION: Although the number of putative TAAs identified is limited, this pilot study suggests that meta-analysis of expression profiles produces results that could assist in the designing of pre-clinical immunopreventive vaccines.

Allergy and Immunology↗

PubMed2005

Vaccination with dendritic cells pulsed with apoptotic tumors in combination with anti-OX40 and anti-4-1BB monoclonal antibodies induces T cell-mediated protective immunity in Her-2/neu transgenic mice.

Tumor cells express tumor-associated antigens (TAAs), which can serve as targets for the immune system. However, the majority of TAAs are overexpressed products of normal cellular genes; as such, self-tolerance mechanisms have hindered their use for the induction of effective antitumor responses. One such normal self-protein is the growth factor receptor Her-2/neu, which is overexpressed in 25-35% of all mammary carcinomas in humans. In previous studies, we have demonstrated that Her-2/neu mice are functionally tolerant to neu antigens and contain only a low avidity T-cell repertoire to neu antigens. However, this residual low-avidity T-cell repertoire has antitumor activity. In this study, we compared the immune responses of Her-2/neu mice immunized with dendritic cells (DCs) pulsed with soluble neu protein or with apoptotic tumor cells. Analysis of the antitumor response shows that Her-2/neu mice vaccinated with DCs pulsed with Her-2/neu antigens retard tumor growth; however, vaccination with DCs pulsed with apoptotic tumor cells induces a stronger antitumor effect. Administration of multiple immunizations in combination with the costimulatory agonist anti-OX40 or anti-4-1BB MAb significantly enhanced the immune responses in these mice, resulting in complete tumor rejection if the tumor burden was small and substantial tumor reduction with a larger tumor burden. These results have important implications for the design of tumor vaccination strategies, suggesting that the use of vaccines that stimulate a broad immune response in combination with costimulatory molecules as immunomodulators could significantly improve the antitumor immune response in tolerant hosts.

Animals↗

PubMed2005

Expression of T cell receptor alpha gene (TCRA) in human rhabdomyosarcoma and other musculo-skeletal sarcomas.

Expression of the T cell receptor (TCR) genes is not restricted to T lymphocytes. Human prostate and breast express a truncated TCR gamma transcript. In the mouse, TCR alpha (TCRA) and beta partial transcripts are expressed by mesenchymal cells and TCRA transcripts by epithelial cells of the kidney. We show now that TCRA constant region expression is common in normal and neoplastic human cells of mesenchymal and neuroectodermal origin. TCR transcripts are derived from an unrearranged TCRA locus. Moreover, rhabdomyosarcoma cells highly expressed a specific J49-C splicing product deriving from the assembly of J49 segment and constant region. TCRA ectopic transcripts/proteins negatively regulate rhabdomyosarcoma cell growth as suggested by TCRA gene expression downmodulation effects using a specific duplex small interfering RNA.

Base Sequence↗

PubMed2005

Antitumor activity of the insulin-like growth factor-I receptor kinase inhibitor NVP-AEW541 in musculoskeletal tumors.

Identification of new drugs is strongly needed for sarcomas. Insulin-like growth factor-I receptor (IGF-IR) was found to provide a major contribution to the malignant behavior of these tumors, therefore representing a very promising therapeutic target. In this study, we analyzed the therapeutic potential of a novel kinase inhibitor of IGF-IR, NVP-AEW541, in Ewing's sarcoma, osteosarcoma, and rhabdomyosarcoma, the three most frequent solid tumors in children and adolescents. NVP-AEW541 inhibits IGF-I-mediated receptor activation and downstream signaling. Ewing's sarcoma cells were generally found to be more sensitive to the effects of this drug compared with rhabdomyosarcoma and osteosarcoma, in agreement with the high dependency of this neoplasm to IGF-IR signaling. NVP-AEW541 induced a G1 cell cycle block in all cells tested, whereas apoptosis was observed only in those cells that show a high level of sensitivity. Concurrent exposure of cells to NVP-AEW541 and other chemotherapeutic agents resulted in positive interactions with vincristine, actinomycin D, and ifosfamide and subadditive effects with doxorubicin and cisplatin. Accordingly, combined treatment with NVP-AEW541 and vincristine significantly inhibited tumor growth of Ewing's sarcoma xenografts in nude mice. Therefore, results encourage inclusion of this drug especially in the treatment of patients with Ewing's sarcoma. For the broadest applicability and best efficacy in sarcomas, NVP-AEW541 may be combined with vincristine, actinomycin D, and ifosfamide, three major drugs in the treatment of sarcomas.

Antineoplastic Combined Chemotherapy Protocols↗

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

Immune prevention of mammary carcinogenesis in HER-2/neu transgenic mice: a microarray scenario.

Neoplastic transformation is a multistep process in which gene products of specific regulatory pathways are involved at each stage. Identification of these overexpressed or mutated gene products provides an unprecedented opportunity to address the immune system against defined antigens and eliminate transformed cells. Mice transgenic for these oncogenes (e.g. HER-2/neu, a prototype of deregulated oncogenic protein kinase membrane receptors) are ideal experimental models for assessing the potential of active immunization. The demonstration that vaccines can cure HER-2/neu transplantable tumors, prevent their onset and delay the progression of preneoplastic lesions in mice at risk suggests that efficient immunological inhibition of HER-2/neu carcinogenesis can be achieved by specific vaccination. To further explore this issue, halting of tumor progression in the mammary glands of BALB-neuT mice with two immunization protocols in two laboratories has been studied independently by DNA microarray analysis. Combination of the two sets of results revealed a clear correlation between them when the tumor mass was titrated by transcription profiling. It was also clear that both protocols induced a strong, polyclonal antibody response and halted tumor growth at a condition very similar to that at which the vaccination began. Differences in the expression profiles were mainly related to the expression levels of a few chemokines and T-cell-specific genes that may be in some way correlated with the efficacy of the vaccination. Last, combination of the expression data with the protection results indicated that chronic vaccination is needed to maintain an active IFN-gamma-mediated response in the mammary gland.

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

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

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

Apc10.1: an ApcMin/+ intestinal cell line with retention of heterozygosity.

APC10.1 is a new intestinal cell line derived from ApcMin/+ mice that retains both the heterozygous Apc genotype and a nonactivated Wnt signaling pathway and displays an early neoplastic phenotype. Although tumorigenic both in immunodepressed and in immunocompetent syngeneic mice, it requires a high cell dose and a long latency. Its epithelial/intestinal origin is shown, in a gene expression profile, by the expression of epithelial transcripts (such as cytokeratin and laminin isoforms) and of developmental regulatory genes (such as Tcf-4, Hnf3beta, p21, Ihh, Hes1) necessary for, or involved in, the maintenance of intestinal stem cells. The lack of activation of the Wnt cascade in APC10.1 cells is shown both by the expression profile of Wnt target genes and by the standard TCF reporter assay. APC10.1 cell line is a novel in vitro model that can contribute to a better understanding of the clinical evolution of familial adenomatous polyposis and to finding of new prophylactic and therapeutic approaches. Supplementary material for this article can be found on the International Journal of Cancer website at http://www.interscience.wiley.com/jpages/0020-7136/suppmat/index.html.

Adenomatous Polyposis Coli↗

PubMed2004

Inhibition of connective tissue growth factor (CTGF/CCN2) expression decreases the survival and myogenic differentiation of human rhabdomyosarcoma cells.

Connective tissue growth factor (CTGF/CCN2), a cysteine-rich protein of the CCN (Cyr61, CTGF, Nov) family of genes, emerged from a microarray screen of genes expressed by human rhabdomyosarcoma cells. Rhabdomyosarcoma is a soft tissue sarcoma of childhood deriving from skeletal muscle cells. In this study, we investigated the role of CTGF in rhabdomyosarcoma. Human rhabdomyosarcoma cells of the embryonal (RD/12, RD/18, CCA) and the alveolar histotype (RMZ-RC2, SJ-RH4, SJ-RH30), rhabdomyosarcoma tumor specimens, and normal skeletal muscle cells expressed CTGF. To determine the function of CTGF, we treated rhabdomyosarcoma cells with a CTGF antisense oligonucleotide or with a CTGF small interfering RNA (siRNA). Both treatments inhibited rhabdomyosarcoma cell growth, suggesting the existence of a new autocrine loop based on CTGF. CTGF antisense oligonucleotide-mediated growth inhibition was specifically due to a significant increase in apoptosis, whereas cell proliferation was unchanged. CTGF antisense oligonucleotide induced a strong decrease in the level of myogenic differentiation of rhabdomyosarcoma cells, whereas the addition of recombinant CTGF significantly increased the proportion of myosin-positive cells. CTGF emerges as a survival and differentiation factor and could be a new therapeutic target in human rhabdomyosarcoma.

Cell Differentiation↗