The present invention provides compositions and methods for treating a tissue disorder associated with a response-to-injury process or proliferating cells in a
mammal. These tissue disorders are associated with a novel
cellular phenotype designated as “transition cells” which are described herein. This
cellular phenotype is characterized in having an activated erk
kinase signaling activity, a stimulated AP-1 binding activity, and at least one characteristic selected from the group consisting of: (a) increased podosome formation, (b) increased flux of
intracellular or
extracellular hyaluronans or hyaladherins, (c) increased expression of a hyaladherin, (d) an inability to form focal adhesions, (e) increased
metalloproteinase activity, and (f) increased expression of a hyaladherin. Example tissue disorders include
fibrosis,
inflammation, degeneration and invasive disorders such as occur in cancerous cells. The methods provided herein include administering to the
mammal, an effective amount of a composition that alters the activity of transition molecules within a
cell Transition molecules are shown to be comprised of hyaladherins, hyaluronans and associated molecules that regulate the transitional
phenotype. A novel
cell culture comprising transition cells is also provided, as well as compositions comprising particular peptides, polypeptides, and antibodies that affect the transitional
phenotype.