INVASIVE EPITHELIAL-CELLS SHOW MORE FAST PLASMA-MEMBRANE MOVEMENTS THAN RELATED OR PARENTAL NONINVASIVE CELLS

Fast plasma membrane movements (FPMM) are involved in ruffling, blebbing, fast shape change, and fast translocation. A simple method for the quantification of FPMM was used to study the relation between FPMM and invasive capacity in five pairs of invasive and non-invasive variants from four different epithelial cell types. The human mammary cell line MCF-7/6, the ras-transformed dog kidney cell line ras-MDCK, the ras-transformed mouse mammary gland cell lines NM9-ras-12 and NM-f-ras-TD, and spontaneously transformed late passage mouse lens explant MLE cells, all of which were invasive in vitro, showed more FPMM in our measurements and displayed more ruffling activity on time-lapse video films than the related or parental MCF-7/AZ, MDCK-3, NM9, and NM-f cell lines and early passage MLE cells, none of which were invasive. Interestingly, induction of invasive capacity in MCF-7/AZ cells by retinoic acid was accompanied by an increase in FPMM, but speed of translocation was not increased. Together these observations support the hypothesis that a certain level of FPMM is a prerequisite for invasive capacity.