1伪,25-Dihydroxyvitamin D₃ inhibits the human H295R cell proliferation by cell cycle arrest: A model for a protective role of vitamin D receptor against adrenocortical cancer

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• 作者：Catia Pilon ; Riccardo Urbanet ; Tracy A. Williams ; Takashi Maekawa ; Silvia Vettore ; Rosa Sirianni ; Vincenzo Pezzi ; Paolo Mulatero ; Ambrogio Fassina ; Hironobu Sasano ; Francesco Fallo
• 关键词：Vitamin D ; H295R cells ; Adrenocortical cancer
• 刊名：The Journal of Steroid Biochemistry and Molecular Biology
• 出版年：March, 2014
• 年：2014
• 卷：140
• 期：Complete
• 页码：26-33
• 全文大小：1622 K

文摘

Using the human H295R adrenocortical carcinoma cell line as a model, we analyzed the role of 1伪,25-dihydroxyvitamin D₃ [1伪,25(OH)₂D₃)]-vitamin D receptor (VDR) axis in the growth of adrenocortical cancer (ACC). The presence of VDR in various adrenocortical tissues, including ACC, was also investigated. DNA synthesis was evaluated by [³H]thymidine cell incorporation after treatment with 1伪,25(OH)₂D₃ at increasing doses. The effect of 1伪,25(OH)₂D₃ on cell cycle and apoptosis was analyzed with a flow cytometer. Cyclin-dependent kinase 4 (CDK4) expression, a molecular marker of G1-S cell cycle transition phase, was evaluated in cells treated with 1伪,25(OH)₂D₃ before and after VDR gene silencing. 1伪,25(OH)₂D₃ treatment inhibited cell proliferation by 20% at a dose of 1 nM, in parallel with steroid secretion decrease. A cell cycle arrest in G1, with no change in apoptotic cell proportion, was observed after 10 nM 1伪,25(OH)₂D₃ cell exposure. CDK4 activation was reduced by 10 nM 1伪,25(OH)₂D₃ but was not affected by 1伪,25(OH)₂D₃ after VDR gene silencing. Expression of VDR mRNA was lower in ACC than in benign adrenocortical tumors. VDR immunostaining was evident in benign tumors but it was weak in ACC tissues.

Conclusions

Slightly supra-physiological concentrations of 1伪,25(OH)₂D₃ have a moderate anti-proliferative effect on H295R cells. Anti-proliferative effect was due to cell cycle arrest in G1 phase, without inducing apoptosis. The low mRNA expression levels at qRT-PCR as well as the weak immunohistochemical expression of VDR in ACC, suggests a protective role of VDR against malignant adrenocortical growth.