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Endogenous inhibitors of angiogenesis, such as thrombospondin-1 (TSP-1), are promising sources of therapeutic agents to treat angiogenesis-driven diseases, including cancer. TSP-1 regulates angiogenesis through different mechanisms, including binding and sequestration of the angiogenic factor fibroblast growth factor-2 (FGF-2), through a site located in the calcium binding type III repeats. We hypothesized that the FGF-2 binding sequence of TSP-1 might serve as a template for the development of inhibitors of angiogenesis. Using a peptide array approach followed by binding assays with synthetic peptides and recombinant proteins, we identified a FGF-2 binding sequence of TSP-1 in the 15-mer sequence DDDDDNDKIPD-DRDN. Molecular dynamics simulations, taking the full flexibility of the ligand and receptor into account, and nuclear magnetic resonance identified the relevant residues and conformational determinants for the peptide-FGF interaction. This information was translated into a pharmacophore model used to screen the NCI2003 small molecule databases, leading to the identification of three small molecules that bound FGF-2 with affinity in the submicromolar range. The lead compounds inhibited FGF-2-induced endothelial cell proliferation in vitro and affected angiogenesis induced by FGF-2 in the chicken chorioallantoic membrane assay. These small molecules, therefore, represent promising leads for the development of antiangiogenic agents. Altogether, this study demonstrates that new biological insights obtained by integrated multidisciplinary approaches can be used to develop small molecule mimics of endogenous proteins as therapeutic agents.

The 45th Annual Meeting of the Italian Cancer Society (SIC), held at the Centro Congressi Giovanni XXIII in Bergamo, Italy on 9-12 November, 2003, attracted almost 400 participants. The Scientific Committee chaired by R Giavazzi (Mario Negri Institute, Bergamo) and the board of the Italian Cancer Society produced a packed and varied program. Plenary sessions with keynote speakers (24 lectures) were combined with oral proffered papers (20 selected presentations), providing a platform from laboratory science to clinical interventions. Two hundred and sixty-one abstracts were submitted to the conference and presented in poster and poster discussion sessions, providing a stimulating ground for discussion and a network of interactive collaboration among young investigators. The venue of Bergamo offered exceptional hospitality with social events in the beautiful old town and at the Modern Art Museum. We hope that the following report gives an idea of the event and will encourage the reader to attend the 46th meeting of the SIC, 24-26 October, 2004 in Pisa.

The 45th Annual Meeting of the Italian Cancer Society (SIC), held at the Centro Congressi Giovanni XXIII in Bergamo, Italy on 9-12 November, 2003, attracted almost 400 participants. The Scientific Committee chaired by R Giavazzi (Mario Negri Institute, Bergamo) and the board of the Italian Cancer Society produced a packed and varied program. Plenary sessions with keynote speakers (24 lectures) were combined with oral proffered papers (20 selected presentations), providing a platform from laboratory science to clinical interventions. Two hundred and sixty-one abstracts were submitted to the conference and presented in poster and poster discussion sessions, providing a stimulating ground for discussion and a network of interactive collaboration among young investigators. The venue of Bergamo offered exceptional hospitality with social events in the beautiful old town and at the Modern Art Museum. We hope that the following report gives an idea of the event and will encourage the reader to attend the 46th meeting of the SIC, 24-26 October, 2004 in Pisa.

Gangliosides are thought to be involved in tumor cell proliferation, migration and invasiveness as so far demonstrated by the addition of exogenous gangliosides to the culture medium. To better understand the direct influence that alterations in ganglioside synthesis can exert on these functional aspects of cell biology, in the present study, we investigated the behaviour of C6 rat glioma cells after stable transfection with the human CMP-NeuAc:NeuAcalpha2-3Galbeta1-4GlcCer alpha2,8-sialyltransferase (SAT-II, EC 2.4.99.8) gene. The enzyme synthesizes ganglioside GD(3) by adding a sialic acid residue to ganglioside GM(3). Stable transfection of the constructs into C6 cells and expression of the human SAT-II gene were evaluated using PCR and RT-PCR amplification, respectively. Qualitative and quantitative analysis of the ganglioside profile was performed by conventional HP-TLC and identity of de novo synthesized species was assessed by TLC immunostaining. Results show that whereas C6 parental cells and C6 cells transfected with the empty expression vector synthesize, almost exclusively, ganglioside GM(3), de novo synthesis of GD(3) is clearly observed in clones expressing the alpha2,8-sialyltransferase. Subcutaneous grafting in athymic nude mice of cells expressing high levels of GD(3) induces tumors growing faster and more aggressively than controls. In in vitro assays, the same cells demonstrate increased proliferation rate, motility and invasiveness. Chemotaxis and chemoinvasion were assayed using the modified Boyden chamber. Data obtained suggest that endogenously neosynthesized GD(3) is able to modify proliferation rate, motility and invasion of C6 rat glioma cells, enhancing the features of malignancy of this tumor cell line.

The effect of paclitaxel on the adhesive and motility properties of human ovarian carcinoma cell lines was investigated. Paclitaxel significantly inhibited the motility of OVCAR 5, SK-OV-3, and HOC-1OTC ovarian carcinoma cell lines (IC50 = 2.1 x 10(-8), 2 x 10(-9), and 1.9 x 10(-8) m, respectively) but did not affect the adhesion of these cells to the subendothelial matrix. The association between inhibition of motility and cytotoxic activity was investigated using an A2780 subclone (1A9) and three paclitaxel-resistant variants (designated 1A9/PTX22, 1A9/PTX10, and 1A9/PTX18). Although paclitaxel did not significantly affect the adhesion to subendothelial matrix of the sublines, it completely inhibited their migration. Inhibition of migration was similar in 1A9 cells and the resistant sublines, with an IC50 of 1 x 10(-8) for 1A9 cells and 5.4 x 10(-9), 1.1 x 10(-8), and 5.2 x 10(-9) m for 1A9/PTX22, 1A9/PTX10, and 1A9/PTX18, respectively. Paclitaxel inhibited motility induced by soluble attractant (chemotaxis) and immobilized attractant (haptotaxis). Inhibition of cell motility occurred in the absence of an antiproliferative effect, because higher concentrations of paclitaxel were required to inhibit tumor cell proliferation (IC50 = 1.9 x 10(-7) and 4.6 x 10(-6), 1 x 10(-5), and 3.1 x 10(-6) m for 1A9 and 1A9/PTX22, 1A9/PTX10, and 1A9/PTX18, respectively). These data show that paclitaxel is a potent inhibitor of ovarian carcinoma cell motility and that this activity is independent of its cytotoxic activity.