Chemotaxis and chemokinesis of malignant mesothelioma cells to multiple growth factors.

Chemotaxis is defined as directional cell movement of cells towards concentration gradients of solubilized attractants, whereas chemokinesis is defined as random cell movement in the absence of chemoattractant gradients. Since tumor cell motility plays an important role in the process of tumor invasion and metastasis, we investigated these two distinct motile behaviors in highly invasive tumor, malignant mesothelioma. Chemotaxis and chemokinesis of mesothelioma cells were assayed using Boyden chambers fitted with filters coated with collagen type IV and different growth factors and cytokines were used as chemoattractants. We found that growth factors such as epidermal growth factor, transforming growth factor-alpha, amphiregulin, heparin-binding epidermal growth factor-like growth factor, beta-cellulin, insulin-like growth factor-I, insulin-like growth factor-II and stem cell factor stimulated directional (chemotactic) and/or random (chemokinetic) motility in all mesothelioma cell lines tested, whereas none of acidic fibroblast growth factor, basic fibroblast growth factor, granulocyte-macrophage colony-stimulating factor or interleukin-6 induced migration in the same mesothelioma cells. These findings provide evidence that: (i) multiple growth factors can induce chemotaxis and chemokinesis in malignant mesothelioma cell lines, and (ii) may contribute to our understanding of the highly invasive behavior of malignant mesotheliomas in vivo.