Effects of the new-identified amphibole fluoro-edenite in lung epithelial cells.

An epidemiological survey on mortality for malignant pleural neoplasm in Italy evidenced a number of patients in Biancavilla, a village located in a volcanic area of eastern Sicily, none of which had been significantly exposed to asbestos during their professional lives. Environmental studies suggested the involvement of the material derived from stone quarries in the disease onset. A detailed crystal-chemical analysis of amphiboles contained in this material allowed the discovery and the identification of a new fiber that was named fluoro-edenite. In order to define the mode of action of fluoro-edenite at a subcellular level, we have conducted a study by using A549 cells, a tumor-cell line from a human lung carcinoma with properties of alveolar epithelial cells. The results obtained showed a remarkable tropism of A549 cells toward fluoro-edenite fibers. In fact, these epithelial cells contacted the fibers via the extension of membrane ruffles and filopodia that allowed the capture and most probably the internalization of material into the cytoplasm. Moreover, fluoro-edenite interfered with epithelial cell physiology, by reducing the proliferation rate without perturbing the cell cycle and increasing the release of the proinflammatory cytokine IL-6, one of the main mediators of asbestos-induced pathophysiological response.