Role of CTNNB1 in the Development of Avian Reproductive System and Ovarian Carcinomas

Abstract

The chicken is an ideal experimental model for researching the various reproductive systems

the developmental biology of vertebrate embryonic gonad, the oviduct development in response to estrogen, the human epithelial-derived ovarian cancer (EOC). Therefore, in this study, we used the chicken as biological research model for investigate: 1) the functional roles and expression pattern of CTNNB1 during the morphological changes of embryonic gonad 2) the estrogen-dependent regulation of CTNNB1 in oviduct development and potential functions as a biomarker of CTNNB1 in human EOC.

Beta-catenin (CTNNB1) is involved in the various biological processes, including embryogenesis, tumorigenesis, angiogenesis and progression of metastasis. CTNNB1, as multifunctional and oncogenic protein, play a important roles in adhesion between Sertoli cells by N-cadherin-dependent manner and in various cancer type by its over-activation. Also CTNNB1 can interact with estrogen/estrogen receptor α complex, which regulated the transcription of Wnt/β-catenin target genes.

First, we identified CTNNB1 that has a crucial role in Sertoli cell adhesion during testicular development. The expression patterns and cell-specific localization of CTNNB1 was determined by qRT-PCR, in situ hybridization and immunohistochemistry in different stage of embryonic gonad development. CTNNB1 mRNA and protein were most abundant during the Sertoli cell maturation and localized in Sertoli cell , which has similar patterns to that detected in CTNNB1-related genes such as ESR α, CCND1 and CDH2. Estrogen is not only stimulate immature Sertoli cell biosynthesis of adhesion protein such as N-cadherin but also induces up-regulation of CCND1 in Sertoli cell. Therefore, CTNNB1 may play a crucial role in proliferation of seminiferous epithelial cells and Sertoli cells during testis morphogenesis.

Secondly, we identified CTNNB1 as a novel biomarker of human EOC. Over active CTNNB1 play a crucial role in tumorigenesis, angiogenesis and progression of metastasis and is also important in ovarian cancer. Thus, we focused on the CTNNB1 gene in the chicken reproductive track including oviduct and ovary. We determined that DES (diethylstilbestrol, a synthetic non-steroidal estrogen) increased CTNNB1 expression in the oviduct development and its expression was localized predominantly in the LE of the magnum. In addition, mRNA and protein of CTNNB1 are significantly expressed in GE of ovarian endometrioid carcinoma, but not the other cancerous and normal ovaries of hens. Further, four miRNAs such as miR-217, miR-1467, miR-1623 and miR-1697 were discovered to influence CTNNB1 expression via its 3-UTR, which suggests post-transcriptional regulation of CTNNB1 expression in chickens. Collectively, results of this study indicate that CTNNB1 is novel in that its expression is up-regulated by estrogen in epithelial cells of the chicken oviduct and that it is also abundantly exist in chicken ovarian endometrioid carcinoma. Therefore, CTTNB1 may be used for mornitoring effects of therapies for ovarian cancer in laying hens.

Collectively, this present study provides new insights into functional roles of CTNNB1 in male and female reproductive tract and Epithelial-derived ovarian carcinogenesis.