We found a match
Your institution may have access to this item. Find your institution then sign in to continue.
- Title
PORCN moonlights in a Wnt-independent pathway that regulates cancer cell proliferation.
- Authors
Covey, Tracy M; Kaur, Simran; Tan Ong, Tina; Proffitt, Kyle D; Wu, Yonghui; Tan, Patrick; Virshup, David M
- Abstract
Porcupine (PORCN) is a membrane-bound O-acyl transferase that is required for the palmitoylation of Wnt proteins, and that is essential in diverse Wnt pathways for Wnt-Wntless (WLS) binding, Wnt secretion, and Wnt signaling activity. We tested if PORCN was required for the proliferation of transformed cells. Knockdown of PORCN by multiple independent siRNAs results in a cell growth defect in a subset of epithelial cancer cell lines. The growth defect is transformation-dependent in human mammary epithelial (HMEC) cells. Additionally, inducible PORCN knockdown by two independent shRNAs markedly reduces the growth of established MDA-MB-231 cancers in orthotopic xenografts in immunodeficient mice. Unexpectedly, the proliferation defect resulting from loss of PORCN occurs in a Wnt-independent manner, as it is rescued by re-expression of catalytically inactive PORCN, and is not seen after RNAi-mediated knockdown of the Wnt carrier protein WLS, nor after treatment with the PORCN inhibitor IWP. Consistent with a role in a Wnt-independent pathway, knockdown of PORCN regulates a distinct set of genes that are not altered by other inhibitors of Wnt signaling. PORCN protein thus appears to moonlight in a novel signaling pathway that is rate-limiting for cancer cell growth and tumorigenesis independent of its enzymatic function in Wnt biosynthesis and secretion.
- Publication
PloS one, 2012, Vol 7, Issue 4, pe34532
- ISSN
1932-6203
- Publication type
Journal Article
- DOI
10.1371/journal.pone.0034532