Evidence Supporting the Oncogenic Role of BAZ1B in Colorectal Cancer

BAZ1B protein, known as WSTF (Williams syndrome transcription factor) is involved in multiple nuclear processes, and its role in cancerogenesis is emerging. However, the function of BAZ1B in colorectal cancer (CRC) remains largely unexplored. BAZ1B immunohistochemistry (IHC) of 100 pairs of matched normal colon and treatment-naïve CRC samples showed higher BAZ1B intensity staining in 93 tumor specimens. BAZ1B IHC staining significantly correlated with tumor size (p-value = 0.035) but not KRAS mutation presence. BAZ1B overexpression significantly enhanced the proliferation of the HCT116 cell line while the small hairpin RNA mediated BAZ1B knockdown inhibited the proliferation of the SW480 cell line. These observations were reproduced when both cell lines were grown as xenografts in the immunodeficient NU/J mice. A transcriptomic survey of HCT116 and SW480 xenografts revealed 2046 and 99 differentially expressed genes (DEGs) at adj. p-value = 0.05, respectively. Functional annotation of DEGs to the Reactome database showed already established, including protein and rRNA metabolism, as well as new molecular processes dependent on BAZ1B protein expression alternation. In conclusion, BAZ1B is overexpressed in CRC tissue and contributes to CRC cell lines proliferation in vitro and in vivo. Our data support the emerging oncogenic role of BAZ1B in cancerogenesis, including CRC.