Cystatin D is a candidate tumor suppressor gene induced by vitamin D in human colon cancer cells

• Published in: The Journal of clinical investigation Vol. 119; no. 8; pp. 2343 - 2358
• Main Authors: Alvarez-Díaz, Silvia, Valle, Noelia, García, José Miguel, Peña, Cristina, Freije, José M P, Quesada, Víctor, Astudillo, Aurora, Bonilla, Félix, López-Otín, Carlos, Muñoz, Alberto
• Format: Journal Article
• Language: English
• Published: United States American Society for Clinical Investigation 01.08.2009
• Subjects: Alfacalcidol; beta Catenin - antagonists & inhibitors; Biomedical research; Cadherins - analysis; Calcifediol; Calcitriol - pharmacology; Care and treatment; Cell Cycle; Cell Differentiation; Cell growth; Cell Line, Tumor; Cell Movement - drug effects; Cell Proliferation - drug effects; Chemical properties; Colon cancer; Colonic Neoplasms - genetics; Colonic Neoplasms - pathology; Colorectal cancer; Cystatins - genetics; Cystatins - physiology; Epithelium - pathology; Gene expression; Genes; Genes, myc; Genes, Tumor Suppressor - physiology; Genetic aspects; Health aspects; Humans; Mesoderm - pathology; Promoter Regions, Genetic; Proteins; Receptors, Calcitriol - analysis; Tumor suppressor genes; Tumors; Vitamin D; Spain
• DOI: 10.1172/jci37205
• ISSN: 0021-9738

The active vitamin D metabolite 1alpha,25-dihydroxyvitamin D3 [1alpha,25(OH)2D3] has wide but not fully understood antitumor activity. A previous transcriptomic analysis of 1alpha,25(OH)2D3 action on human colon cancer cells revealed cystatin D (CST5), which encodes an inhibitor of several cysteine proteases of the cathepsin family, as a candidate target gene. Here we report that 1alpha,25(OH)2D3 induced vitamin D receptor (VDR) binding to, and activation of, the CST5 promoter and increased CST5 RNA and protein levels in human colon cancer cells. In cells lacking endogenous cystatin D, ectopic cystatin D expression inhibited both proliferation in vitro and xenograft tumor growth in vivo. Furthermore, cystatin D inhibited migration and anchorage-independent growth, antagonized the Wnt/beta-catenin signaling pathway, and repressed c-MYC expression. Cystatin D repressed expression of the epithelial-mesenchymal transition inducers SNAI1, SNAI2, ZEB1, and ZEB2 and, conversely, induced E-cadherin and other adhesion proteins. CST5 knockdown using shRNA abrogated the antiproliferative effect of 1alpha,25(OH)2D3, attenuated E-cadherin expression, and increased c-MYC expression. In human colorectal tumors, expression of cystatin D correlated with expression of VDR and E-cadherin, and loss of cystatin D correlated with poor tumor differentiation. Based on these data, we propose that CST5 has tumor suppressor activity that may contribute to the antitumoral action of 1alpha,25(OH)2D3 in colon cancer.