Cell cycle–related kinase is a direct androgen receptor–regulated gene that drives β-catenin/T cell factor–dependent hepatocarcinogenesis
Hai Feng, … , Ka F. To, Joseph J.Y. Sung
Hai Feng, … , Ka F. To, Joseph J.Y. Sung
Published July 11, 2011
Citation Information: J Clin Invest. 2011;121(8):3159-3175. https://doi.org/10.1172/JCI45967.
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Research Article Oncology

Cell cycle–related kinase is a direct androgen receptor–regulated gene that drives β-catenin/T cell factor–dependent hepatocarcinogenesis

Abstract

Hepatocellular carcinoma (HCC) is the fifth most common cancer worldwide. It is more prevalent in men than women. Related to this, recent genetic studies have revealed a causal role for androgen receptor (AR) in hepatocarcinogenesis, but the underlying molecular mechanism remains unclear. Here, we used genome-wide location and functional analyses to identify a critical mediator of AR signaling — cell cycle–related kinase (CCRK) — that drives hepatocarcinogenesis via a signaling pathway dependent on β-catenin and T cell factor (TCF). Ligand-bound AR activated CCRK transcription and protein expression via direct binding to the androgen-responsive element of the CCRK promoter in human HCC cell lines. In vitro analyses showed that CCRK was critical in human cell lines for AR-induced cell cycle progression, hepatocellular proliferation, and malignant transformation. Ectopic expression of CCRK in immortalized human liver cells activated β-catenin/TCF signaling to stimulate cell cycle progression and to induce tumor formation, as shown in both xenograft and orthotopic models. Conversely, knockdown of CCRK decreased HCC cell growth, and this could be rescued by constitutively active β-catenin or TCF. In primary human HCC tissue samples, AR, CCRK, and β-catenin were concordantly overexpressed in the tumor cells. Furthermore, CCRK overexpression correlated with the tumor staging and poor overall survival of patients. Our results reveal a direct AR transcriptional target, CCRK, that promotes hepatocarcinogenesis through the upregulation of β-catenin/TCF signaling.

Authors

Hai Feng, Alfred S.L. Cheng, Daisy P. Tsang, May S. Li, Minnie Y. Go, Yue S. Cheung, Gui-jun Zhao, Samuel S. Ng, Marie C. Lin, Jun Yu, Paul B. Lai, Ka F. To, Joseph J.Y. Sung

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Figure 9

CCRK overexpression correlates with AR and active β-catenin levels in human HCCs.

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CCRK overexpression correlates with AR and active β-catenin levels in hu...
(A) Western blot analysis of AR, CCRK, and active β-catenin in 16 representative primary HCC tissues (T) and their paired nontumor (NT) tissues as well as 2 normal liver specimens. β-actin was used as a loading control. M, male; F, female. (B) Relative protein expression levels of AR, CCRK, and active β-catenin in 33 paired HCC and nontumor tissues. The boxes represent the interquartile range; lines within boxes and whiskers denote median and 10–90 percentiles, respectively. (C) Correlation among AR, CCRK, and active β-catenin in 33 paired HCCs and matched nontumor tissues denoted with Pearson’s correlation coefficients. (D) Immunohistochemical staining of AR, CCRK, and β-catenin in the serial sections of a representative HCC case (#532M). AR staining showed strong nuclear positivity in the tumor cells. CCRK staining of the same area showed moderate strong cytoplasmic perinuclear positivity, while scattered nuclear positivity was also noted. β-catenin staining of the same area showed strong nuclear positivity. Original magnification, ×200 (low power); ×400 (high power). ***P < 0.0001. Data are presented as mean + SD of 3 independent experiments.