Heterozygous <i>Ctnnb1</i> inactivation does not prevent mouse ovarian endometrioid adenocarcinoma (OEA) development and the reduction in <i>Ctnnb1 dosage or CTNNB1</i> transcripts shows differential effects on selected β-catenin/TCF target genes.

<p>(A) Representative photomicrographs of H&E stained ovarian cancer tissue sections from <i>Apc</i>^<i>fl/fl</i><i>Pten</i>^<i>fl/fl</i>, and <i>Apc</i>^<i>fl/fl</i><i>Pten</i>^<i>fl/fl</i><i>Ctnnb1</i>^<i>fl/+</i> mice show similar morphologic characteristics independent of <i>Ctnnb1</i> gene dosage, with areas of glandular, overtly epithelial differentiation admixed with more poorly differentiated spindle-cell areas. Scale bars, 100 μm. (B) Representative photomicrographs of β-catenin immunohistochemical staining in tumors from <i>Apc</i>^<i>fl/fl</i><i>Pten</i>^<i>fl/fl</i> mice, showing strong nuclear β-catenin translocation and moderate cytoplasmic staining, whereas tumors from <i>Apc</i>^<i>fl/fl</i><i>Pten</i>^<i>fl/fl</i><i>Ctnnb1</i>^<i>fl/+</i> mice showed weak nuclear and moderate cytoplasmic β-catenin staining. Scale bars, 25 μm. (C) cDNAs were obtained from murine normal ovaries (Cntrl, n = 4) and OEAs from <i>Apc</i>^<i>fl/fl</i><i>Pten</i>^<i>fl/fl</i><i>Ctnnb1</i>^<i>fl/+</i> (n = 6), and <i>Apc</i>^<i>fl/fl</i><i>Pten</i>^<i>fl/fl</i> (n = 6) mice following AdCre injection. Transcript levels of <i>Ctnnb1</i>, <i>Axin2</i>, <i>Myc</i> and <i>Nkd1</i> were measured by qRT-PCR analysis and normalized with β-actin. The gene expression levels were set to 1 for control (Cntrl) group. <i>Error bars</i> denote S.D. **<i>P</i> < 0.01 and *<i>P <</i> 0.05. (D) TOV-112D cells (the human OEA-derived cell line harboring β-catenin gain of function mutation), stably transduced with two different doxycycline-inducible shRNAs targeting <i>CTNNB1</i> (<i>CTNNB1</i>-1 and <i>CTNNB1</i>-2) or a non-silencing scramble shRNA (Scrmbl), were treated for 4 days with DOX (“+ DOX”) or a solvent control (“- DOX”). <i>CTNNB1</i> shRNA-mediated effects on <i>CTNNB1</i> (left) and <i>MYC</i> (right) gene expression are shown. Gene expression was assessed by qRT-PCR and normalized to <i>HPRT</i> expression. <i>Error bars</i> denote S.D. *<i>P</i> < 0.05 in Student's <i>t</i> test.