Chemokines have been shown to chemoattract and activate different leukocyte populations. Here we report the in vitro effect of macrophage inflammatory protein (MIP)-1a, MIP-1b, regulated on activation, normal T-cells, expressed and secreted (RANTES), monocyte chemotactic protein-1 (MCP-1), interleukin-8 (IL-8), interferon inducible protein-10 (IP-10), neutrophil-activating peptide-2 (NAP-2), growthrelated protein (GRO)-a and GRO-g, on the migration of 3 human breast carcinoma cell lines, MCF-7, T47D and ZR-75-1, using a microchemotaxis chamber to assess migration across fibronectin-coated polycarbonate membranes. MCF-7 cells responded chemotactically to all chemokines tested in a pattern which was dose and time dependent, although responses to the different chemokines were variable. ZR-75-1 responded to MIP-1b and GRO-a, giving maximum migration indices of 3.7 and 5.3, respectively, and exhibited a migratory response to MIP-1a, IL-8 and MCP-1 although to a lower degree. T47D was unresponsive to the chemokines tested, but both MCF-7 and T47D cells bound radiolabelled ligands with binding constants (Kd) ranging from 0.6 to 2.2 nM and 0.6 to 2.1 nM, respectively. The specificity of the chemotactic response of MCF-7 to MIP-1a and MIP-1b was confirmed using chemokine-specific neutralising antibodies and heat denaturation, and was demonstrated to involve G protein and cyclic AMP signalling pathways. MIP-1b and MIP-1a were shown to induce changes in the organisation of the actin cytoskeleton and the level of F-actin in MCF-7 cells, as determined using flow cytometric analysis and confocal microscopy. Our results show that breast carcinoma cells can respond to chemokines, and suggests a potential role for these molecules in the process of tumour cell migration, invasion and metastasis. Int. J. Cancer 71:257-266, 1997.r 1997 Wiley-Liss, Inc.Chemokines are an ever expanding family of proinflammatory cytokines with more than 20 recognised family members, the majority showing between 20 and 80% homology in their amino acid sequences and possessing a conserved 4 cysteine residues motif (Baggiolini et al., 1994). The separation into the a and b subfamilies is based on 2 criteria: the presence or the absence, respectively, of an intervening amino acid residue located between the first 2 of the 4 conserved cysteines, and the clustering of genes encoding the a and b chemokines to human chromosomes 4 and 17, respectively. Murine lymphotactin (Kelner et al., 1994) and the human homologue SCM-1 (Yoshida et al., 1995) contain only 2 of the 4 conserved cysteines found in the other family members and constitute a distant third subfamily (the C or g type subfamily).All chemokine family members have been shown to induce the directional migration of particular inflammatory cell types, including granulocytes, monocytes and lymphocytes (Baggiolini et al., 1994). These proteins have also been shown to be active over a wide concentration range and are produced by a variety of cell types in response to primary proinflammatory mediators such a...

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Administration of active TG2 to two different in vitro angiogenesis assays resulted in the accumulation of a complex extracellular matrix (ECM) leading to the suppression of endothelial tube formation without causing cell death. Matrix accumulation was accompanied by a decreased rate of ECM turnover, with increased resistance to matrix metalloproteinase-1. Intratumor injection of TG2 into mice bearing CT26 colon carcinoma tumors demonstrated a reduction in tumor growth, and in some cases tumor regression. In TG2 knockout mice, tumor progression was increased and survival rate reduced compared to wild-type mice. In wild-type mice, an increased presence of TG2 was detectable in the host tissue around the tumor. Analysis of CT26 tumors injected with TG2 revealed fibrotic-like tissue containing increased collagen, TG2-mediated crosslink and reduced organized vasculature. TG2-mediated modulation of cell behavior via changes in the ECM may provide a new approach to solid tumor therapy.

Direct intratumor injection of a disabled infectious single cycle HSV-2 virus encoding the murine GM-CSF gene (DISC/mGM-CSF) into established murine colon carcinoma CT26 tumors induced a significant delay in tumor growth and complete tumor regression in up to 70% of animals. Pre-existing immunity to HSV did not reduce the therapeutic efficacy of DISC/mGM-CSF, and, when administered in combination with syngeneic dendritic cells, further decreased tumor growth and increased the incidence of complete tumor regression. Direct intratumor injection of DISC/mGM-CSF also inhibited the growth of CT26 tumor cells implanted on the contralateral flank or seeded into the lungs following i.v. injection of tumor cells (experimental lung metastasis). Proliferation of splenocytes in response to Con A was impaired in progressor and tumor-bearer, but not regressor, mice. A potent tumor-specific CTL response was generated from splenocytes of all mice with regressing, but not progressing tumors following in vitro peptide stimulation; this response was specific for the gp70 AH-1 peptide SPSYVYHQF and correlated with IFN-γ, but not IL-4 cytokine production. Depletion of CD8+ T cells from regressor splenocytes before in vitro stimulation with the relevant peptide abolished their cytolytic activity, while depletion of CD4+ T cells only partially inhibited CTL generation. Tumor regression induced by DISC/mGM-CSF virus immunotherapy provides a unique model for evaluating the immune mechanism(s) involved in tumor rejection, upon which tumor immunotherapy regimes may be based.