SRY-box transcription factor 9 (SOX9) (SOX9)

SRY-box transcription factor 9 (SOX9) is a master regulatory protein belonging to the SOX family of transcription factors, characterized by a highly conserved high-mobility group (HMG) DNA-binding domain [7, 13]. It plays a fundamental role in embryonic development, particularly in orchestrating chondrogenesis and male sex determination by regulating the expression of genes such as COL2A1 and Anti-Müllerian Hormone (AMH) [14, 16]. In adult tissues, SOX9 is involved in maintaining stem cell pools and facilitating tissue repair in organs like the liver, intestine, and pancreas [6, 10]. However, its dysregulation is linked to severe pathologies; loss-of-function mutations cause campomelic dysplasia, a lethal skeletal malformation syndrome, while its overexpression is a hallmark of many cancers, including colorectal, pancreatic, and prostate malignancies [1, 15, 16]. In oncology, SOX9 promotes tumor initiation, metastasis, and chemoresistance by inducing epithelial-mesenchymal transition (EMT) and maintaining cancer stem cell properties [3, 9, 11]. Although traditionally considered undruggable, SOX9 is an emerging therapeutic target with strategies including small molecule inhibitors, epigenetic modulators, and RNA-based therapies currently under investigation to suppress its oncogenic activity or promote regeneration in degenerative diseases like osteoarthritis [5, 12, 21].

Other names

SOX9CMD1CMPD1SRA1SRXX2SRXY10SRY-box 9Transcription factor SOX-9ENH13TESCO

SOX9-targeted therapies primarily aim to interfere with its transcriptional activity by inhibiting DNA binding at the HMG-box domain or disrupting essential protein-protein interactions with co-factors like BRD4 or RBPJ [32, 35]. Other mechanisms include the modulation of upstream regulatory pathways such as PI3K/AKT/mTOR, Wnt/beta-catenin, and Notch signaling to downregulate SOX9 expression, as well as the use of RNA interference (siRNA/shRNA) or CRISPR/Cas9 to reduce protein levels or stability [5, 19, 34].