Poster Presentation 14th International Biennial Conference on Metastasis Research 2012

Resistance to anoikis alters the adhesion and promotes the increase of syndecan-4 and heparanase expression in endothelial cells in culture. (#177)

Paulo Pernambuco Filho 1 2 , Bruna Carneiro 1 2 , Douglas Silva 1 2 , Ana Paula Vasconcelos 1 2 , Maria Aparecida Pinhal 1 , Helena Bonciani Nader 1 , Carla Cristina Lopes 1 2
  1. Bioquímica, UNIFESP, São Paulo, SP, Brasil
  2. Ciências Biológicas, UNIFESP, São Paulo, SP, Brasil

Tumor cells present important characteristics about the changes in the mechanism of adhesion, which is related to changes in cell-cell and cell-extracellular matrix (ECM) contacts. The proliferation, invasion and maintenance of the tumors are strictly correlated to proteoglycans. Syndecan-4, a heparan sulfate proteoglycan (HSPG), has an important role in the mechanism of cell adhesion by its interaction with extracellular ligands. Changes in its expression have been observed in tumor cells, indicating its involvement in cancer. The acquisition of resistance to cell death induced by blockade of adhesion to the substratume (anoikis resistance) is a feature of neoplastic transformation and a critical step during the metastatic process.
In this study, endothelial cells derived from rabbit aorta (EC) were subjected to transformation induced by blockade of adhesion to the substratume (adh-EC). After one deadhesion cycle, phenotypic alterations were observed in the few surviving cells, which became more numerous and showed progressive alterations after each adhesion impediment step.
EC cells and adh-EC clones obtained were tested in nude mice to observe their tumorigenic capacity. Tumor development was observed in mice injected with adh-EC clones. Sulfated glycosaminoglycans (SGAG) synthesized by the cells were metabolically labeled with [35S] sulfate (150µCi/ml). SGAG from both medium and cells were extracted by proteolysis and identified by radioautography of the agarose gel electrophoresis. An increase in heparan sulfate (HS) synthesis was detected in the adh-EC clones. Analysis of the expression of the syndecan-4 protein core by RT-PCR and heparanase expression by Real Time PCR suggests this proteoglycan is related to HS chains increase. Also, an increase in adhesion to fibronectin, laminin and collagen IV was observed in adh-EC clones. These findings suggest that syndecan-4 is involved in acquisition of tumor cell resistance induced by anchorage independence in EC cells, thus contributing to neoplastic transformation.
Supported by FAPESP, CNPq and CAPES.