Increased cellular apoptosis susceptibility (CSE1L/CAS) protein expression promotes protrusion extension and enhances migration of MCF-7 breast cancer cells

Microtubules are part of cell structures that play a role in regulating the migration of cancer cells. The cellular apoptosis susceptibility (CSE1L/CAS) protein is a microtubule-associated protein that is highly expressed in cancer. We report here that CSE1L regulates the association of alpha-tubulin with beta-tubulin and promotes the migration of MCF-7 breast cancer cells. CSElL was associated with alpha-tubulin and beta-tubulin in GST (glutathione S-transferase) pull-down and immunoprecipitation assays. CSE1L-GFP (green fluorescence protein) fusion protein experiments showed that the N-terminal of CSE1L interacted with microtubules. Increased CSElL expression resulted in decreased tyrosine phosphorylation of alpha-tubulin and beta-tubulin, increased alpha-tubulin and It-tubulin association, and enhanced assembly of microtubules. Cell protrusions or pseudopodia are temporary extensions of the plasma membrane and are implicated in cancer cell migration and invasion. Increased CSE1L expression increased the extension of MCF-7 cell protrusions. In vitro migration assay showed that enhanced CSE1L expression increased the migration of MCF-7 cells. Our results indicate that CSE1L plays a role in regulating the extension of cell protrusions and promotes the migration of cancer cells. (C) 2010 Elsevier Inc. All rights reserved.