Cystatin D is a candidate tumor suppressor  gene induced by vitamin D in human  colon cancer cells.
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.
Alvarez-Díaz
Silvia
S
Instituto de Investigaciones Biomédicas Alberto Sols, Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid, Madrid, Spain.
Valle
Noelia
N
García
José Miguel
JM
Peña
Cristina
C
Freije
José M P
JM
Quesada
Víctor
V
Astudillo
Aurora
A
Bonilla
Félix
F
López-Otín
Carlos
C
Muñoz
Alberto
A
D015820:Cadherins / Q000032:analysis; D002117:Calcitriol / Q000494:pharmacology*; D002453:Cell Cycle; D002454:Cell Differentiation; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D003110:Colonic Neoplasms / Q000235:genetics* / Q000473:pathology; D015891:Cystatins / Q000235:genetics* / Q000502:physiology; D004848:Epithelium / Q000473:pathology; D016147:Genes, Tumor Suppressor / Q000502:physiology*; D016259:Genes, myc; D006801:Humans; D008648:Mesoderm / Q000473:pathology; D011401:Promoter Regions, Genetic; D018167:Receptors, Calcitriol / Q000032:analysis; D051176:beta Catenin / Q000037:antagonists & inhibitors
C495270:CTNNB1 protein, human; D015820:Cadherins; D015891:Cystatins; D018167:Receptors, Calcitriol; D051176:beta Catenin; C071378:CST5 protein, human; D002117:Calcitriol