Publication date: Jan 11, 2021
Melanoma cells have been shown to undergo fast amoeboid or Leader Bleb-Based Migration (LBBM), requiring a large and stable bleb for migration. In leader blebs, is a rapid flow of cortical actin that drives the cell forward. Here, we tested the hypothesis that the actin severing factors, ADF and cofilin-1, are essential for contractility and actin flow for LBBM. Using RNAi in melanoma A375 cells, we find that co-depleting ADF and cofilin-1 led to a large increase in the level of cortical actin, suggesting that ADF and cofilin-1, together, regulate cortical actin in these cells. Moreover, RNAi of ADF and cofilin-1 increased the number of cortical, polymerization competent, barbed-ends. Therefore, severing by these proteins appears to promote cortical actin turnover. Furthermore, actin severing factors can promote contractility through the regulation of actin architecture. In agreement with this concept, RNAi of ADF and cofilin-1 led to a significant decrease in cell stiffness. As LBBM is stimulated by cell confinement, we then used confined cells to evaluate the role of ADF and cofilin-1 in regulating actin dynamics. We found cofilin-1 to be enriched at leader bleb necks, whereas RNAi of ADF and cofilin-1 reduced bleb sizes and the frequency of motile cells. Strikingly, cells without ADF and cofilin-1 had blebs with abnormally long necks. Many blebs failed to retract and displayed slower actin turnover and flow in the absence of ADF and cofilin-1. Collectively, our data identifies ADF and cofilin-1 as actin remodeling factors required for the amoeboid migration of melanoma cells.
|drug||DRUGBANK||Dextrose unspecified form|
|drug||DRUGBANK||Sodium lauryl sulfate|