Trinkaus 9723054 The overall objective of the proposed research is to understand how normal tissue cells and cancer cells move invasively within organisms - as individual cells, cell clusters, cell streams and as cell sheets. Since there is now abundant evidence that normal tissue cells and cancer cells utilize the same mechanisms for their invasive movements, both in vitro and in viva, any increase in understanding how one moves will aid in understanding the movement of the other. The emphasis in this research is on the mechanism of cell motility, particularly during directional cell movements, how cells make contacts with each other and with various substrata over which they move, how tightly-joined cells in epithelia move to rearrange, and how their movements are coordinated, and how cells respond to possible exogenous signals and move directionally. More specifically, the investigations will be concerned with protrusive activity of the cell surface, particularly at the leading edge, contractility, cytoplasmic structure and programmed endocytosis as morphogenetic mechanisms, the organization of actin-containing microfilaments as related to cytoplasmic contractilitv, and tension during gastrulation, presence and orientation of microtubules as related to the spreading movements of cortical cytoplasm during epibolv, the ingression of cells at the surface of the gastrula as related to the formation of the epiblast and hypoblast, the role of contact inhibition and other coordinated interactions between and among cells during directional morphogenetic cell movements, and the possible role of retraction induced protrusive activity in the promotion of the persistence of cell movements in a particular direction. The principal techniques that will be utilized are: cell culture, high resolution differential interference contrast and phase contrast optics, confocal micrography, time-lapse video filming of moving cells in vivo and in vitro, high resolution photomicrography, microsurgery and micr omanipulation for transplantation and deletion experiments, inhibiting cell contractility with cytochalazin D and depolymerizing microtubules with nocodazole and immobilizing them with taxol, staining microtubules with fluorescent antibodies against tubulin, microinjecting fluorescent labels to follow moving cells, transmission and scanning electron microscopy - all in relation to cell motility. As many of these techniques as apply will be brought to bear in the analysis of each problem.
