Altered cytoskeletal structures in transformed cells exhibiting obviously metastatic capabilities

Abstract

Cytoskeletal changes in transformed cells (LM-51) exhibiting obviously metastatic capabilities were investigated by utilization of double-fluorescent labelling through combinations of: (1) tubulin indirect immunofluoreseonce plus Rhodamine-phalloidin staining of F-actins; (2) indirect immunofluorescent staining with α-actinin polyclonal- and vinculin monoclonal antibodies. The LM-51 cells which showed metastatic index of >50% were derived from lung metastasis in nude mice after subcutaneous inoculation of human highly metastatic tumor DNA transfected NIH3T3 cell transformants. The parent NIH3T3 cells exhibited well-organized microtubules, prominent stress fibers and adhesion plaques while their transformants showed remarkable eytoskeletal alterations: (l) reduced microtubules but increased MTOC fluorescence; (2) disrupted stress fibers and fewer adheaion plaques with their protein components redistributed in the cytoplasm; (3) F-actin- and α-actinin/vinculin aggregates appeared in the cytoplasm. These aggregates were dot-like, varied in size (0.1–0.4μm) and number, located near the ventral surface of the cells. TPA-induced actin/vineulin bodies were studied too. Indications that aotin and α-actinin/vinoulin redistribution might be important alterations involved in the expression of metastatic capabilities of LM-51 transformed cells were discussed.