A. Modesti

Cytokines, tumour-cell death and immunogenicity: a question of choice.

Abstract How do cytokines released by engineered tumour cells provoke tumour rejection and an immune memory? Is vaccination with tumour cells that have been engineered to secrete cytokines a viable therapeutic perspective? Piero Musiani and colleagues have sought an answer to these questions by transfecting the same tumour with the genes of various cytokines and elucidating the features of the reactions elicited.

IL-6 Expression in Neurons of Transgenic Mice Causes Reactive Astrocytosis and Increase in Ramified Microglial Cells but no Neuronal Damage

Growing evidence suggests that aberrant production of inflammatory cytokines within the central nervous system (CNS) contributes to the development of pathological conditions. To test the cause—effect relationship between the overproduction of interleukin‐6 (IL‐6) in the CNS and the onset of neuropathological changes, we have generated transgenic mice in which human IL‐6 expression has been targeted to the neurons by using the rat neuron‐specific enolase promoter. These mice develop reactive astrocytosis and an increase in ramified microglial cells but do not show histological or behavioural signs of neuron damage at the light microscope level. We thus conclude that a constant release of human IL‐6 by neuronal subpopulations in mice is sufficient to activate cells potentially capable of modulating the local immune response, but at the same time is compatible with normal neuron functions.

A common repertoire of autoantibodies is shared by cancer and autoimmune disease patients: Inflammation in their induction and impact on tumor growth

The repertoire of autoantibodies found in cancer patients partly overlaps with that typical of patients with autoimmune diseases. Beside the biochemical and immunological properties of the target antigens and their altered expression in tumor tissues, the intratumoral inflammatory context can play a key role in the induction of autoimmune disease-associated autoantibodies in cancer patients. Furthermore, the impact of such antibodies on cancer growth and progression can be deeply influenced by the interplay with inflammation. The characterization of the spontaneous humoral responses occurring in cancer patients, of the mechanisms that trigger and sustain the autoantibody response and of the biological effects of such autoantibodies may help the rational design of anti-cancer immunotherapeutic protocols.

The expression of LEC/CCL16, a powerful inflammatory chemokine, is upregulated in ulcerative colitis.

Ulcerative colitis (UC) is a chronic inflammatory disease of unknown aetiology and pathogenesis. The presence in the colonic mucosa of reactive cells expressing proinflammatory cytokines and chemokines is associated with high levels of IL-10, an anti-inflammatory cytokine. Our aim was to investigate the role of IL-10 and the β chemokine LEC/CCL16 selectively up-regulated by IL-10 in inflammatory cell recruitment and cytokine and chemokine production during UC. We studied histologically, immunohistochemically and ultrastructurally colonic biopsies from 20 active UC patients and 10 control specimens taken far from any macroscopically detectable lesion in age and sex-matched patients with noninflammatory bowel disease. In active UC, immature dendritic cells (DCs) in the LP are associated with IL-10 in the T cell rich area. Furthermore, most of the LP-infiltrating macrophages strongly expressed LEC/CCL16, a chemokine upregulated by IL-10. To evaluate if LEC/CCL16 plays a role in the inflammatory reaction present in UC, we performed morphological studies in mice injected s.c. with syngeneic tumor cells engineered to produce LEC/CCL16. We found that the LEC protein locally released by LEC-gene-transfected tumor cells is a potent proinflammatory chemokine that induces the recruitment of a reactive infiltrate, and an angiogenic process mirroring that in human UC. In conclusion our data indicate that: 1) LEC is endowed with a powerful inflammatory activity and 2) upregulated in active UC, when IL-10 expression is elevated in a T cell rich area, 3) this upregulation can be seen as a pro-inflammatory pathway triggered by IL-10 in UC.

EXTRACELLULAR MATRIX REMODELLING IN A MURINE MAMMARY ADENOCARCINOMA TRANSFECTED WITH THE INTERFERON‐ALPHA1 GENE

The rejection of interferon alpha1 gene‐transfected mammary adenocarcinoma cells (TSA‐IFNα) injected into syngeneic BALB/c mice was accompanied by an unusual stromal reaction and marked CD8‐positive T‐lymphocyte involvement. To investigate the biological background of this reaction, the possibility was evaluated that an interaction between TSA‐IFNα and stromal cells might remodel the extracellular matrix (EM). When fibroblasts were co‐cultured with TSA‐IFNα or treated with exogenous IFNα, there was no change in their replication rate or collagen synthesis. By contrast, their fibronectin (FN) production and release were increased, resulting in enhanced fibroblast chemotaxis. These findings were mirrored by increased FN staining in the peritumoural and tumoural areas in vivo. IFNα thus determines increased FN production and hence massive local recruitment and activation of fibroblasts, with a modification of the EM. The several activities of IFNα should thus be considered prior to its employment in clinical trials.

Modulation of laminin synthesis in human neuroblastoma cells during retinoic acid induced differentiation.

A comparable pattern of morphological neuronal differentiation was induced in the human neuroblastoma cell line SMS-KCNR by treatment with either retinoic acid (RA) or exogenous laminin (LM). LM expression and synthesis by SMS-KCNR was increased upon RA treatment which involved the cell bound, rather than the secreted protein. These data suggest an involvement of LM in the neuroblastoma differentiation process manifested both as an ability of LM to induce a morphological neuronal differentiation and as a selective control on LM metabolism during RA induced neuronal differentiation.

Cytogenetic, Molecular, Immunologic, and Ultrastructural Study on an Established Cell Line of a Stage III Neuroblastoma

Neuroblastoma, representing about 7% of childhood malignant tumors, is the most common neoplasm in infancy and second in malignancy after lymphoma as a solid tumor outside the central nervous system in childhood. Its differential diagnosis from other tumors can be difficult and requires diagnostic approaches other than histological analysis.