Role of gp91phox Homolog Nox1 in Induction of Premalignant Spindle Phenotypes of HPV 16 E6/E7—Immortalized Human Keratinocytes

The NADPH oxidase (Nox) family of superoxide- and hydrogen peroxide—producing proteins has been recognized as important for signal transduction that regulates receptor-mediated functions, including cytoskeleton remodeling, cell proliferation, migration, differentiation, and cell death. Nox1 was the first of the Nox catalytic subunits to be cloned and shown to induce tumorigenic conversion of mouse fibroblasts. While Nox1 has been shown to be expressed in human colon and prostate cancers, however, limited studies have demonstrated the involvement of Nox1 in an early step of cell transformation. The aim of this review is to provide an overview on the role of Nox1 in cancer, as well as the contribution of our studies to demonstrate the involvement of Nox1 on neoplastic progression of human keratinocytes beyond the immortalization step. The generation of spindle phenotypes concomitant with anchorage-independent growth and invasiveness will be highlighted and discussed in relation to the possible role of Nox1 in epithelial-mesenchymal transition. Understanding these mechanisms may provide insight into Nox1 and redox signaling components as potential therapeutic targets to inhibit tumor progression.