Biomedical subjects

Raffaele A Calogero

Publications and source records attributed to Raffaele A Calogero.

5 recordsLinked to original sources

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↗

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

Purification of recombinant proteins with high isoelectric points.

The use of recombinant antigens is essential for the construction of robust and sensitive diagnostic assays. A critical step in the preparation of recombinant antigens is protein purification. Purification problems may be very different for related structural proteins expressed in the same host or for the same protein expressed in different hosts, because the biochemical characteristics of a recombinant protein, expressed in a heterologous system, are unique. In this chapter we make a brief introduction to protein purification procedures and we present a quick purification process suitable for the isolation of recombinant protein having high isoelectric points encoding non-conformational epitopes.

Antibodies, Viral↗

PubMed2004

Microarray data analysis and mining.

DNA microarray is an innovative technology for obtaining information on gene function. Because it is a high-throughput method, computational tools are essential in data analysis and mining to extract the knowledge from experimental results. Filtering procedures and statistical approaches are frequently combined to identify differentially expressed genes. However, obtaining a list of differentially expressed genes is only the starting point because an important step is the integration of differential expression profiles in a biological context, which is a hot topic in data mining. In this chapter an integrated approach of filtering and statistical validation to select trustable differentially expressed genes is described together with a brief introduction on data mining focusing on the classification of co-regulated genes on the basis of their biological function.

Cluster Analysis↗

PubMed2001

The human MDM2 oncoprotein increases the transcriptional activity and the protein level of the p53 homolog p63.

Genetic alteration of the p53 tumor suppressor gene, which monitors DNA damage and operates cell cycle checkpoints, is a major factor in the development of human malignancies. The p53 protein belongs to a family that also includes two structurally related proteins, p63 and p73. Although all three proteins share similar transcriptional functions and antiproliferative effects, each of them appears to play a distinct role in development and tumor suppression. One of the principal regulators of p53 activity is the MDM2 protein. The interaction of MDM2 with p53 inhibits p53 transcriptional activity and targets p53 for ubiquitin-dependent degradation. The ability of MDM2 to inhibit p53 functions is antagonized by the ARF oncosuppressor protein. We show here that like p53, the p63alpha and p63gamma isoforms are able to associate with human MDM2 (HDM2). Overexpression of HDM2 increased the steady-state level of intracellular p63 and enhanced its transcriptional activity. Both effects appeared to be counteracted by ARF coexpression. These data indicate that p63 can be activated by HDM2 under conditions in which p53 is inhibited. Therefore, HDM2 expression could support p63-specific transcriptional functions on a common set of genes, keeping interference by p53 at a minimum.

Animals↗