Silencing mutated β-catenin inhibits cell proliferation and stimulates apoptosis in the adrenocortical cancer cell line H295R

• Published in: PloS one Vol. 8; no. 2; p. e55743
• Main Authors: Gaujoux, Sébastien, Hantel, Constanze, Launay, Pierre, Bonnet, Stéphane, Perlemoine, Karine, Lefèvre, Lucile, Guillaud-Bataille, Marine, Beuschlein, Felix, Tissier, Frédérique, Bertherat, Jérôme, Rizk-Rabin, Marthe, Ragazzon, Bruno
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 07.02.2013; Public Library of Science (PLoS)
• Subjects: Adrenal Cortex Neoplasms - genetics; Adrenal Cortex Neoplasms - metabolism; Adrenocortical Carcinoma - genetics; Adrenocortical Carcinoma - metabolism; Animals; Apoptosis; Apoptosis - genetics; beta Catenin - genetics; Biology; Cancer; Cell cycle; Cell Cycle - genetics; Cell growth; Cell Line, Tumor; Cell Proliferation; Cloning; Deactivation; Disease Models, Animal; Experiments; Female; G1 phase; Gene expression; Gene Silencing; Humans; Inactivation; Inoculation; Kinases; Medical prognosis; Mice; Mutation; Neoplasia; Neuroendocrine tumors; Proteins; Reduction; RNA Interference; Signal Transduction; Signaling; TCF Transcription Factors - metabolism; Transcription, Genetic; Transplantation, Heterologous; Tumorigenesis; Tumors; Wnt protein; Wnt Proteins - metabolism; Xenografts; β-Catenin; France
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0055743

Adrenocortical carcinoma (ACC) is a rare and highly aggressive endocrine neoplasm, with limited therapeutic options. Activating β-catenin somatic mutations are found in ACC and have been associated with a poor clinical outcome. In fact, activation of the Wnt/β-catenin signaling pathway seems to play a major role in ACC aggressiveness, and might, thus, represent a promising therapeutic target. Similar to patient tumor specimen the H295 cell line derived from an ACC harbors a natural activating β-catenin mutation. We herein assess the in vitro and in vivo effect of β-catenin inactivation using a doxycyclin (dox) inducible shRNA plasmid in H295R adrenocortical cancer cells line (clone named shβ). Following dox treatment a profound reduction in β-catenin expression was detectable in shβ clones in comparison to control clones (Ctr). Accordingly, we observed a decrease in Wnt/βcatenin-dependent luciferase reporter activity as well as a decreased expression of AXIN2 representing an endogenous β-catenin target gene. Concomitantly, β-catenin silencing resulted in a decreased cell proliferation, cell cycle alterations with cell accumulation in the G1 phase and increased apoptosis in vitro. In vivo, on established tumor xenografts in athymic nude mice, 9 days of β-catenin silencing resulted in a significant reduction of CTNNB1 and AXIN2 expression. Moreover, continous β-catenin silencing, starting 3 days after tumor cell inoculation, was associated with a complete absence of tumor growth in the shβ group while tumors were present in all animals of the control group. In summary, these experiments provide evidences that Wnt/β-catenin pathway inhibition in ACC is a promising therapeutic target.