This Article Full Text Full Text (PDF) Supplementary Data Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Cataisson, C. Articles by Yuspa, S. H. Search for Related Content PubMed PubMed Citation Articles by Cataisson, C. Articles by Yuspa, S. H.

Inducible Cutaneous Inflammation Reveals a Protumorigenic Role for Keratinocyte CXCR2 in Skin Carcinogenesis

Laboratory of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, Maryland

Requests for reprints: Stuart H. Yuspa, Laboratory of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Institute, 37 Convent Drive, MSC-4255, Building 37, Room 4068, Bethesda, MD 20892-4255. Phone: 301-496-2162; Fax: 301-496-8709; E-mail: yuspas{at}mail.nih.gov.

Key Words: PKC • inflammation • skin • cancer • CXCR2 • chemokines

Transgenic mice that overexpress PKC in the epidermis (K5-PKC mice) exhibit acute CXCR2-mediated intraepidermal neutrophilic inflammation and a strong epidermal hyperplasia in response to application of 12-O-tetradecanoylphorbol-13-acetate (TPA). We now show that hyperplasia is independent of infiltrating neutrophils. Furthermore, when K5-PKC mice were initiated with 7,12-dimethylbenz(a)anthracene (DMBA) and promoted with a low dose of TPA, 58% of K5-PKC mice developed skin papillomas that progressed to carcinoma, whereas wild-type mice did not develop tumors. We confirmed that CXCR2 is expressed by keratinocytes and showed that transformation by oncogenic ras (a hallmark of DMBA initiation) or TPA exposure induced all CXCR2 ligands. Ras induction of CXCR2 ligands was mediated by autocrine activation of epidermal growth factor receptor and nuclear factor-B, and potentiated by PKC. Oncogenic ras also induced CXCR2 ligands in keratinocytes genetically ablated for CXCR2. However, ras transformed CXCR2 null keratinocytes formed only small skin tumors in orthotopic skin grafts to CXCR2 intact hosts, whereas transformed wild-type keratinocytes produced large tumors. In vitro, CXCR2 was essential for CXCR2 ligand-stimulated migration of ras-transformed keratinocytes and for ligand activation of the extracellular signal-regulated kinase (ERK) and Akt pathways. Both migration and activation of ERK and Akt were restored by CXCR2 reconstitution of CXCR2 null keratinocytes. Thus, activation of CXCR2 on ras-transformed keratinocytes has both promigratory and protumorigenic functions. The up-regulation of CXCR2 ligands after initiation by oncogenic ras and promotion with TPA in the mouse skin model provides a mechanism to stimulate migration by both autocrine and paracrine pathways and contribute to tumor development. [Cancer Res 2009;69(1):319–28]