Glucocorticoids induce CCN5/WISP-2 expression and attenuate invasion in oestrogen receptor-negative human breast cancer cells.
ABSTRACT CCN5 (cysteine-rich 61/connective tissue growth factor/nephroblastoma overexpressed 5)/WISP-2 [WNT1 (wingless-type MMTV integration site family, member 1)-inducible signalling pathway protein 2] is an oestrogen-regulated member of the CCN family. CCN5 is a transcriptional repressor of genes associated with the EMT (epithelial-mesenchymal transition) and plays an important role in maintenance of the differentiated phenotype in ER (oestrogen receptor)-positive breast cancer cells. In contrast, CCN5 is undetectable in more aggressive ER-negative breast cancer cells. We now report that CCN5 is induced in ER-negative breast cancer cells such as MDA-MB-231 following glucocorticoid exposure, due to interaction of the endogenous glucocorticoid receptor with a functional glucocorticoid-response element in the CCN5 gene promoter. Glucocorticoid treatment of MDA-MB-231 cells is accompanied by morphological alterations, decreased invasiveness and attenuated expression of mesenchymal markers, including vimentin, cadherin 11 and ZEB1 (zinc finger E-box binding homeobox 1). Interestingly, glucocorticoid exposure did not increase CCN5 expression in ER-positive breast cancer cells, but rather down-regulated ER expression, thereby attenuating oestrogen pathway signalling. Taken together, our results indicate that glucocorticoid treatment of ER-negative breast cancer cells induces high levels of CCN5 expression and is accompanied by the appearance of a more differentiated and less invasive epithelial phenotype. These findings propose a novel therapeutic strategy for high-risk breast cancer patients.
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ABSTRACT: We recently demonstrated that mice lacking epidermal glucocorticoid (GC) receptor (GR) (GR epidermal knock-out or GR(EKO) mice) have developmental defects and sensitivity to epidermal challenge in adulthood. We examined the susceptibility of GR(EKO) mice to skin chemical carcinogenesis. GR(EKO) mice treated with a low dose of DMBA followed by PMA promotion exhibited earlier papilloma formation with higher incidence and multiplicity relative to control littermates (CO). Augmented proliferation and inflammation, and defective differentiation of GR(EKO) keratinocytes contributed to the phenotype, likely through increased AKT and STAT3 activities. GR(EKO) tumors exhibited signs of early malignization, including delocalized expression of laminin A, dermal invasion of keratin (K)5-positive cells, K13 expression, and focal loss of E-cadherin. Cultured GR(EKO) keratinocytes were spindle-like, with loss of E-cadherin and upregulation of smooth muscle actin and Snail, suggesting partial epithelial-mesenchymal transition. A high DMBA dose followed by PMA promotion generated sebaceous adenomas and melanocytic foci in GR(EKO) and CO. Importantly, the number, growth kinetics and extent of both tumor types increased in GR(EKO) mice, suggesting that in addition to regulating tumorigenesis from epidermal lineages, GR in keratinocytes is important for cross-talk with other skin cells. Altogether, our data reinforce the importance of GR in the pathogenesis of skin cancer.Journal of Investigative Dermatology accepted article preview online, 11 June 2013; doi:10.1038/jid.2013.255.Journal of Investigative Dermatology 06/2013; · 6.19 Impact Factor
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ABSTRACT: Canonical and non-canonical Wnt pathways are involved in the genesis of multiple tumors; however, their role in pituitary tumorigenesis is mostly unknown. This study evaluated gene and protein expression of Wnt pathways in pituitary tumors and whether these expression correlate to clinical outcome. GENES OF THE WNT CANONICAL PATHWAY: activating ligands (WNT11, WNT4, WNT5A), binding inhibitors (DKK3, sFRP1), β-catenin (CTNNB1), β-catenin degradation complex (APC, AXIN1, GSK3β), inhibitor of β-catenin degradation complex (AKT1), sequester of β-catenin (CDH1), pathway effectors (TCF7, MAPK8, NFAT5), pathway mediators (DVL-1, DVL-2, DVL-3, PRICKLE, VANGL1), target genes (MYB, MYC, WISP2, SPRY1, TP53, CCND1); calcium dependent pathway (PLCB1, CAMK2A, PRKCA, CHP); and planar cell polarity pathway (PTK7, DAAM1, RHOA) were evaluated by QPCR, in 19 GH-, 18 ACTH-secreting, 21 non-secreting (NS) pituitary tumors, and 5 normal pituitaries. Also, the main effectors of canonical (β-catenin), planar cell polarity (JNK), and calcium dependent (NFAT5) Wnt pathways were evaluated by immunohistochemistry. There are no differences in gene expression of canonical and non-canonical Wnt pathways between all studied subtypes of pituitary tumors and normal pituitaries, except for WISP2, which was over-expressed in ACTH-secreting tumors compared to normal pituitaries (4.8x; p = 0.02), NS pituitary tumors (7.7x; p = 0.004) and GH-secreting tumors (5.0x; p = 0.05). β-catenin, NFAT5 and JNK proteins showed no expression in normal pituitaries and in any of the pituitary tumor subtypes. Furthermore, no association of the studied gene or protein expression was observed with tumor size, recurrence, and progressive disease. The hierarchical clustering showed a regular pattern of genes of the canonical and non-canonical Wnt pathways randomly distributed throughout the dendrogram. Our data reinforce previous reports suggesting no activation of canonical Wnt pathway in pituitary tumorigenesis. Moreover, we describe, for the first time, evidence that non-canonical Wnt pathways are also not mis-expressed in the pituitary tumors.PLoS ONE 01/2013; 8(4):e62424. · 3.53 Impact Factor
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ABSTRACT: It has been proposed that the epithelial-mesenchymal transition (EMT) in mammary epithelial cells and breast cancer cells generates stem cell features. WISP2 (Wnt-1-induced signaling protein-2) plays an important role in maintenance of the differentiated phenotype of estrogen receptor-positive breast cancer cells and loss of WISP2 is associated with EMT. We now report that loss of WISP2 in MCF7 breast cancer cells can also promote the emergence of a cancer stem-like cell phenotype characterized by high expression of CD44, increased aldehyde dehydrogenase activity and mammosphere formation. Higher levels of the stem cell markers Nanog and Oct3/4 were observed in those mammospheres. In addition we show that low-cell inoculums are capable of tumor formation in the mammary fat pad of immunodeficient mice. Gene expression analysis show an enrichment of markers linked to stem cell function such as SOX9 and IGFBP7 which is linked to TGF-β inducible, SMAD3-dependent transcription. Taken together, our data demonstrate that WISP2 loss promotes both EMT and the stem-like cell phenotype.PLoS ONE 01/2014; 9(2):e87878. · 3.53 Impact Factor