Cystatin D Locates in the Nucleus at Sites of Active Transcription and Modulates Gene and Protein Expression

• Published in: The Journal of biological chemistry Vol. 290; no. 44; pp. 26533 - 26548
• Main Authors: Ferrer-Mayorga, Gemma, Alvarez-Díaz, Silvia, Valle, Noelia, De Las Rivas, Javier, Mendes, Marta, Barderas, Rodrigo, Canals, Francesc, Tapia, Olga, Casal, J. Ignacio, Lafarga, Miguel, Muñoz, Alberto
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 30.10.2015; American Society for Biochemistry and Molecular Biology
• Subjects: Cell Biology; Cell Line, Tumor; colon cancer; Colonic Neoplasms - genetics; Colonic Neoplasms - metabolism; Colonic Neoplasms - pathology; Core Binding Factor Alpha 1 Subunit - genetics; Core Binding Factor Alpha 1 Subunit - metabolism; Core Binding Factor Alpha 2 Subunit - genetics; Core Binding Factor Alpha 2 Subunit - metabolism; Cystatins - genetics; Cystatins - metabolism; cysteine protease; cytokine; Cytokines - biosynthesis; Cytokines - genetics; gene expression; Gene Expression Regulation, Neoplastic; Humans; MEF2 Transcription Factors - genetics; MEF2 Transcription Factors - metabolism; Neoplasm Proteins - genetics; Neoplasm Proteins - metabolism; protease inhibitor; Proteomics; Transcription, Genetic; cysteine protease; cytokine; protease inhibitor; colon cancer; gene expression
• DOI: 10.1074/jbc.M115.660175
• ISSN: 0021-9258

Cystatin D is an inhibitor of lysosomal and secreted cysteine proteases. Strikingly, cystatin D has been found to inhibit proliferation, migration, and invasion of colon carcinoma cells indicating tumor suppressor activity that is unrelated to protease inhibition. Here, we demonstrate that a proportion of cystatin D locates within the cell nucleus at specific transcriptionally active chromatin sites. Consistently, transcriptomic analysis show that cystatin D alters gene expression, including that of genes encoding transcription factors such as RUNX1, RUNX2, and MEF2C in HCT116 cells. In concordance with transcriptomic data, quantitative proteomic analysis identified 292 proteins differentially expressed in cystatin D-expressing cells involved in cell adhesion, cytoskeleton, and RNA synthesis and processing. Furthermore, using cytokine arrays we found that cystatin D reduces the secretion of several protumor cytokines such as fibroblast growth factor-4, CX3CL1/fractalkine, neurotrophin 4 oncostatin-M, pulmonary and activation-regulated chemokine/CCL18, and transforming growth factor B3. These results support an unanticipated role of cystatin D in the cell nucleus, controlling the transcription of specific genes involved in crucial cellular functions, which may mediate its protective action in colon cancer. Background: Cystatin D is a cysteine protease inhibitor with tumor suppressor action. Results: A proportion of cystatin D protein localizes within the cell nucleus at specific active chromatin sites and regulates gene transcription. Conclusion: Cystatin D is a multifunctional protein with protease inhibitory and gene regulatory activities. Significance: Regulation of cystatin D in colon cancer cells has phenotypic consequences beyond the inhibition of lysosomal and secreted cysteine proteases.