ß-catenin activates TGF-ß-induced epithelial-mesenchymal transition in adenomyosis.

Adenomyosis is defined as the presence of ectopic nests of endometrial glands and stroma within the myometrium. Adenomyosis is a common cause of dysmenorrhea, menorrhagia, and chronic pelvic pain but is often underdiagnosed. Despite its prevalence and severity of symptoms, its pathogenesis and etiology are poorly understood. Our previous study showed that aberrant activation of ß-catenin results in adenomyosis through epithelial-mesenchymal transition. Using transcriptomic and ChIP-seq analysis, we identified activation of TGF-ß signaling in the uteri of mutant mice that expressed dominant stabilized ß-catenin in the uterus. There was a strong positive correlation between ß-catenin and TGF-ß2 proteins in women with adenomyosis. Furthermore, treatment with pirfenidone, a TGF-ß inhibitor, increased E-cadherin expression and reduced cell invasiveness in Ishikawa cells with nuclear ß-catenin. Our results suggest that ß-catenin activates TGF-ß-induced epithelial-mesenchymal transition in adenomyosis. This finding describes the molecular pathogenesis of adenomyosis and the use of TGF-ß as a potential therapeutic target for adenomyosis.

Constitutive WNT/CTNNB1 activation triggers spermatogonial stem cell proliferation and germ cell depletion.

The differentiation of germ cells into oogonia or spermatogonia is the first step that eventually gives rise to fully mature gametes. In the female fetal gonad, the RSPO1/WNT/CTNNB1 signalling pathway is involved in primordial germ cell proliferation and differentiation into female germ cells, which are able to enter meiosis. In the postnatal testis, the WNT/CTNNB1 pathway also mediates proliferation of spermatogonial stem cells and progenitor cells. Here we show that forced activation of the WNT/CTNNB1 pathway in fetal gonocytes using transgenic mice leads to deregulated spermatogonial proliferation, and exhaustion of the spermatocytes by apoptosis, resulting in a hypoplastic testis. These findings demonstrate that a finely tuned timing in WNT/CTNNB1 signalling activity is required for spermatogenesis.

Stabilization of beta-catenin induces pancreas tumor formation.

BACKGROUND & AIMS: beta-Catenin signaling within the canonical Wnt pathway is essential for pancreas development. However, the pathway is normally down-regulated in the adult organ. Increased cytoplasmic and nuclear localization of beta-catenin can be detected in nearly all human solid pseudopapillary neoplasms (SPN), a rare tumor with low malignant potential. Conversely, pancreatic ductal adenocarcinoma (PDA) accounts for the majority of pancreatic tumors and is among the leading causes of cancer death. Whereas activating mutations within beta-catenin and other members of the canonical Wnt pathway are rare, recent reports have implicated Wnt signaling in the development and progression of human PDA. Here, we sought to address the role of beta-catenin signaling in pancreas tumorigenesis. METHODS: Using Cre/lox technology, we conditionally activated beta-catenin in a subset of murine pancreatic cells in vivo. RESULTS: Activation of beta-catenin results in the formation of large pancreatic tumors at a high frequency in adult mice. These tumors resemble human SPN based on morphologic and immunohistochemical comparisons. Interestingly, stabilization of beta-catenin blocks the formation of pancreatic intraepithelial neoplasia (PanIN) in the presence of an activating mutation in Kras that is known to predispose individuals to PDA. Instead, mice in which beta-catenin and Kras are concurrently activated develop distinct ductal neoplasms that do not resemble PanIN lesions. CONCLUSIONS: These results demonstrate that activation of beta-catenin is sufficient to induce pancreas tumorigenesis. Moreover, they indicate that the sequence in which oncogenic mutations are acquired has profound consequences on the phenotype of the resulting tumor.