17β-Estradiol upregulates and activates WOX1/WWOXv1 and WOX2/WWOXv2 in vitro: potential role in cancerous progression of breast and prostate to a premetastatic state in vivo

Abstract

Human WWOX gene encodes a proapoptotic WW domaincontaining oxidoreductase WOX1 (also named WWOX, FOR2 or WWOXv1). Apoptotic and stress stimuli activate WOX1 via Tyr33 phosphorylation and nuclear translocation. WOX1 possesses a tetrad NSYK motif in the Cterminal short-chain alcohol dehydrogenase/reductase (SDR) domain, which may bind estrogen and androgen. Here, we determined that 17b-estradiol (E 2 ) activated WOX1, p53 and ERK in COS7 fibroblasts, primary lung epithelial cells, and androgen receptor (AR)-negative prostate DU145 cells, but not in estrogen receptor (ER)-positive breast MCF7 cells. Androgen also activated WOX1 in the AR-negative DU145 cells. These observations suggest that sex hormone-mediated Tyr33 phosphorylation and nuclear translocation of WOX1 is independent of ER and AR. Stress stimuli increase physical binding of p53 with WOX1 in vivo. We determined here that E 2 increased the formation of p53/WOX1 complex and their nuclear translocation in COS7 cells; however, nuclear translocation of this complex could not occur in MCF7 cells. By immunohistochemistry, we determined that progression of prostate from normal to hyperplasia, cancerous and metastatic stages positively correlate with upregulation and activation of WOX1 and WOX2 (FOR1/WWOXv2). In contrast, breast cancer development to a premetastatic state is associated with upregulation and Tyr33 phosphorylation of cytosolic WOX1 and WOX2, followed by significant downregulation or absent expression during metastasis. These Tyr33-phosphorylated proteins are mostly located in the mitochondria without translocating to the nuclei, which is comparable to those findings in cultured breast cancer cells. Together, sex steroid hormone-induced activation of WOX1 and WOX2 is independent of ER and AR, and this activation positively correlates with cancerous progression of prostate and breast to a premetastatic state.

Inhibition of the Wnt/β-catenin pathway by the WWOX tumor suppressor protein

“…The genetic events leading to high b-catenin activity in breast cancer have not yet been elucidated. We hypothesized that the lack of WWOX expression, which is frequent in breast cancer tissues (Driouch et al, 2002;Guler et al, 2004Guler et al, , 2005Chang et al, 2005), might constitutively stimulate the Wnt/b-catenin pathway and thereby contribute to enhancing tumor growth. Our observation that knockdown of WWOX enhances Wnt-3a transcriptional activity, as well as that WWOX overexpression inhibits Dvl-1 transcriptional activity in MCF-7 and BT474 cells, supports this hypothesis.…”

“…The expression of WWOX is reduced or lost in many different cancers (Aqeilan et al, 2007c). Notably, it has been established that WWOX is inactivated in invasive breast carcinoma (Guler et al, 2004Chang et al, 2005;Nunez et al, 2005;Wang et al, 2009). The decrease of WWOX expression is frequently associated with a worse clinical outcome for patients (Pluciennik et al, 2006;Hezova and Ehrmann JKolar 2007;Aqeilan et al, 2007a).…”

WW Domain-Containing Oxidoreductase is a Potential Receptor for Sex Steroid Hormones

“…The activated WWOX/WOX1 interacts with a large spectrum of proteins without possessing a PPXY motif(s), including proteins in the stress signaling and apoptotic response, as well as transcription factors Del Mare et al, 2009). These proteins are p53 (Lo et al, 2008;Chang et al, 2001Chang et al, , 2003aChang et al, , 2005aChang et al, , 2005bLai et al, 2005), JNK1 (Lo et al, 2008;Chang et al, 2003a), MDM2 (Chang et al, 2005a), Zfra (Hong et al, 2007;Hsu et al, 2008), and Hyal-2 ). The C-terminal SDR domain in WOX1/WWOX has been shown to bind Tau, a microtubulebinding protein involved in neurodegeneration (Sze et al, 2004).…”

“…For example, WWOX/WOX1 controls the activation of transcription factors, including p53 (Lo et al, 2008;Chang et al, 2001Chang et al, , 2003aChang et al, , 2003bChang et al, , 2005aChang et al, , 2005bLai et al, 2005), p73 (Aqeilan et al, 2004a), AP2 (Aqeilan et al, 2004b), c-Jun (Gaudio et al, 2006;Li et al, 2009), and CREB . By immunoelectron microscopy, FRET (Förster resonance energy transfer) and co-immunoprecipitation, we have revealed the complex formation of the Tyr33-phosphorylated or activated WOX1 with p-CREB and p-c-Jun in vivo .…”

Pc2‐mediated SUMOylation of WWOX is essential for its suppression of DU145 prostate tumorigenesis

“…The loss of WWOX in cancers is primarily due to genomic instability derived from chromosomal deletions and translocations [12]. Several stimuli such as tumor necrosis factor-a (TNFa), steriod hormone 17b-estradiol, anisomycin or UV light resulted in change in subcellular localization, and phosphorylation on Tyr33 residue of WWOX [13,14]. In addition, WWOX ubiquitination was reported to take place by activated tyrosine kinase (AcK1)-mediated its phosphorylation, leading to its degradation [15].…”