Faculty : Emeritus

Robert Warren, Ph.D.

Many aspects of the process of cellular transformation that leads to cancer in vivo can be studied in cultured cells. My interests have focused on the dramatic changes in shape and behavior that occur in normal cultured cells when they are treated with the transforming growth factors, TGF-” and TGF-B. NRK cells growing normally will spread out and adhere tightly to the culture dish. Internally, the cellular actin cytoskeleton is organized into an extensive system of filament bundles that attach to focal adhesions and stabilize cell shape. Within a few hours of the application of transforming growth factors, the actin filament bundles are disrupted and the cells adopt a spherical shape that is weakly adherent to the dish. This radical structural change in the cell shape and actin organization is correlated with the down-regulation of isoforms of tropomyosin, a protein that binds to and stabilizes actin filaments. I am particularly interested in the mechanisms of transformation that induce the change in expression level of tropomyosin and how its loss contributes to the cytoskeletal breakdown and cell shape remodeling, using methods of cell culture, cell microinjection, and fluorescence imaging of live cells.

Teaching Awards

Dr. Warren is the recipient of the 2014 University of Miami Miller School of Medicine George Paff Award for Excellence in Medical Education

Select Publications

  • C. L. Leonardi, R. H. Warren, and R. W. Rubin. Lack of tropomyosin correlates with the absence of stress fibers in transformed rat kidney cells. Biochim. Biophys. Acta 720:154-162 (1982).
  • R. H. Warren, E. Gordon and R. Azarnia. Tropomyosin in peripheral ruffles of cultured rat kidney cells. Eur. J. Cell Biol. 38:245-253 (1985).
  • R. H. Warren TGF-a-induced breakdown of stress fibers and degradation of tropomyosin in NRK cells is blocked by a proteasome inhibitor. Experimental Cell Res. 236:294-303 (1997).