Active invadopodia of mesenchymally migrating cancer cells contain both beta and gamma cytoplasmic actin isoforms

作者：Simiczyjew Aleksandra^*; Mazur Antonina Joanna; Ampe Christophe; Malicka Blaszkiewicz Maria; van Troys Marleen; Nowak Dorota

来源：Experimental Cell Research, 2015, 339(2): 206-219.

DOI：10.1016/j.yexcr.2015.11.003

• Cytoplasmic actin isoforms
• Invadopodia
• Cancer cells invasion

Invadopodia are actin-rich protrusions formed by mesenchymally migrating cancer cells. They are mainly composed of actin, actin-associated proteins, integrins and proteins of signaling machineries. These protrusions display focalized proteolytic activity towards the extracellular matrix. It is well known that polymerized (F-)actin is present in these structures, but the nature of the actin isoform has not been studied before. We here show that both cytoplasmic actin isoforms, beta- and gamma-actin, are present in the invadopodia of MDA-MB-231 breast cancer cells cultured on a 2D-surface, where they colocalize with the invadopodial marker cortactin. Invadopodial structures formed by the cells in a 3D-collagen matrix also contain beta- and gamma-actin. We demonstrate this using isoform-specific antibodies and expression of fluorescently-tagged actin isoforms. Additionally, using simultaneous expression of differentially tagged beta- and gamma-actin in cells, we show that the actin isoforms are present together in a single invadopodium. Cells with an increased level of beta- or gamma-actin, display a similar increase in the number and size of invadopodia in comparison to control cells. Moreover, increasing the level of either actin isoforms also increases invasion velocity.

• 出版日期2015-12-10