WNT4 mediates the autocrine effects of growth hormone in mammary carcinoma cells.
The expression of Wingless and Int-related protein (Wnt) ligands is aberrantly high in human breast cancer. We report here that WNT4 is significantly upregulated at the mRNA and protein level in mammary carcinoma cells expressing autocrine human growth hormone (hGH). Depletion of WNT4 using small interfering (si) RNA markedly decreased the rate of human breast cancer cell proliferation induced by autocrine hGH. Forced expression of WNT4 in the nonmalignant human mammary epithelial cell line MCF-12A stimulated cell proliferation in low and normal serum conditions, enhanced cell survival and promoted anchorage-independent growth and colony formation in soft agar. The effects of sustained production of WNT4 were concomitant with upregulation of proliferative markers (c-Myc, Cyclin D1), the survival marker BCL-XL, the putative WNT4 receptor FZD6 and activation of ERK1 and STAT3. Forced expression of WNT4 resulted in phenotypic conversion of MCF-12A cells, such that they exhibited the molecular and morphological characteristics of mesenchymal cells with increased cell motility. WNT4 production resulted in increased mesenchymal and cytoskeletal remodeling markers, promoted actin cytoskeleton reorganization and led to dissolution of cell-cell contacts. In xenograft studies, tumors with autocrine hGH expressed higher levels of WNT4 and FZD6 when compared with control tumors. In addition, Oncomine data indicated that WNT4 expression is increased in neoplastic compared with normal human breast tissue. Accordingly, immunohistochemical detection of WNT4 in human breast cancer biopsies revealed higher expression in tumor tissue vs normal breast epithelium. WNT4 is thus an autocrine hGH-regulated gene involved in the growth and development of the tumorigenic phenotype.
Centre de Recherche en Cancérologie de LyonUMR INSERM 1052-CNRS 5286, Centre Léon Bérard, Université Claude Bernard Lyon I, Université de Lyon, Lyon, France.
Cécile M
CM
Vouyovitch
Liggins InstituteUniversity of Auckland, Auckland, New Zealand.
Jo K
JK
Perry
Liggins InstituteUniversity of Auckland, Auckland, New Zealand.
Dong Xu
DX
Liu
Centre de Recherche en Neurosciences de LyonUMR INSERM U1028-CNRS5292, Université de Lyon, Lyon, France.
Laurent
L
Bezin
Department of Human GeneticsUniversity of California, Los Angeles, California, USA.
Eric
E
Vilain
Centre de Recherche en Cancérologie de LyonUMR INSERM 1052-CNRS 5286, Centre Léon Bérard, Université Claude Bernard Lyon I, Université de Lyon, Lyon, France.
Jean-Jacques
JJ
Diaz
Cancer Science Institute of Singapore and Department of PharmacologyNational University of Singapore, Singapore, Republic of Singapore.
Peter E
PE
Lobie
Centre de Recherche en Cancérologie de LyonUMR INSERM 1052-CNRS 5286, Centre Léon Bérard, Université Claude Bernard Lyon I, Université de Lyon, Lyon, France hichem.mertani@lyon.unicancer.fr.
Hichem C
HC
Mertani
D017209:Apoptosis; D001940:Breast / Q000378:metabolism; D001943:Breast Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D002460:Cell Line; D002465:Cell Movement; D049109:Cell Proliferation; D005260:Female; D019382:Human Growth Hormone / Q000378:metabolism*; D006801:Humans; D061986:MCF-7 Cells; D012333:RNA, Messenger / Q000378:metabolism; D060528:Wnt4 Protein / Q000235:genetics / Q000378:metabolism*
D012333:RNA, Messenger; C555581:WNT4 protein, human; D060528:Wnt4 Protein; D019382:Human Growth Hormone
FZD6; WNT4; autocrine growth hormone; breast cancer