Special AT-rich sequence-binding protein 2 acts as a negative regulator of stemness in colorectal cancer cells

• Published in: World journal of gastroenterology : WJG 2016-10, Vol.22 (38), p.8528-8539
• Main Authors: Li, Ying, Liu, Yu-Hong, Hu, Yu-Ying, Chen, Lin, Li, Jian-Ming
• Format: Article
• Language: English
• Subjects: 2; Colorectal; AT-rich; Basic Study; Biomarkers, Tumor - metabolism; cancer; Stemness; Metastasis; CD24 Antigen - metabolism; Cell Adhesion; Cell Line, Tumor; Cell Movement; Cell Proliferation; Chromatin Immunoprecipitation; Colorectal Neoplasms - genetics; Colorectal Neoplasms - metabolism; Gene Expression Regulation, Neoplastic; Humans; Hyaluronan Receptors - metabolism; Matrix Attachment Region Binding Proteins - metabolism; Neoplasm Metastasis; Neoplastic Stem Cells - cytology; Phenotype; Plasmids - metabolism; protein; Real-Time Polymerase Chain Reaction; RNA, Messenger - metabolism; sequence-binding; Special; Transcription Factors - metabolism
• ISSN: 1007-9327; 2219-2840
• DOI: 10.3748/wjg.v22.i38.8528

AIM To find the mechanisms by which special AT-rich sequence-binding protein 2(SATB2) influences colorectal cancer(CRC) metastasis.METHODS Cell growth assay, colony-forming assay, cell adhesion assay and cell migration assay were used to evaluate the biological characteristics of CRC cells with gain or loss of SATB2. Sphere formation assay was used to detect the self-renewal ability of CRC cells. The m RNA expression of stem cell markers in CRC cells with upregulated or downregulated SATB2 expression was detected by quantitative real-time polymerase chain reaction. Chromatin immunoprecipitation(Ch IP) was used to verify the binding loci of SATB2 on genomic sequences of stem cell markers. The Cancer Genome Atlas(TCGA) database and our clinical samples wereanalyzed to find the correlation between SATB2 and some key stem cell markers.RESULTS Downregulation of SATB2 led to an aggressive phenotype in SW480 and DLD-1 cells, which was characterized by increased migration and invasion abilities. Overexpression of SATB2 suppressed the migration and invasion abilities in SW480 and SW620 cells. Using sequential sphere formation assay to detect the selfrenewal abilities of CRC cells, we found more secondary sphere formation but not primary sphere formation in SW480 and DLD-1 cells after SATB2 expression was knocked down. Moreover, most markers for stem cells such as CD133, CD44, AXIN2, MEIS2 and NANOG were increased in cells with SATB2 knockdown and decreased in cells with SATB2 overexpression. Ch IP assay showed that SATB2 bound to regulatory elements of CD133, CD44, MEIS2 and AXIN2 genes. Using TCGA database and our clinical samples, we found that SATB2 was correlated with some key stem cell markers including CD44 and CD24 in clinical tissues of CRC patients.CONCLUSION SATB2 can directly bind to the regulatory elements in the genetic loci of several stem cell markers and consequently inhibit the progression of CRC by negatively regulating stemness of CRC cells.