Snail, also called SNAIL1 or SNAI1, is a zinc-finger transcription factor belonging to the Snail superfamily and encoded by the SNAI1 gene (1,2). Snail was first discovered in Drosophila and has homologs in many species including vertebrates and humans (1,2). The Snail family members includes Snail (Snail1), Slug (Snail2), and Smuc (Snail3) (1,2). In humans, Snail is expressed in a number of tissues including placenta, brain, and skeletal muscle, but is most highly expressed by the kidneys (1). Snail functions in repression of E-cadherin transcription which is associated with epithelial-mesenchymal transition (EMT) that is especially prominent during embryonic development (1-5). Along with Snail, other related EMT-inducing transcription factors (EMT-TFs) include the Twist and ZEB protein families (3). Snail is synthesized as a protein of 264 amino acids (aa) with an N-terminal SNAG domain, a serine-rich domain (SRD), nuclear export sequences (NES), and four C-terminal zinc-finger binding domains, with a theoretical molecular weight of 29 kDa (1,3). Snail activity is largely regulated through post-translational modifications such as phosphorylation, ubiquitination, and glycosylation, which impacts Snail's localization and stability, amongst other things (1-3, 5).
In addition to its role in embryonic development, Snail-induced EMT is also associated with cancer metastasis (1-5). Snail is expressed in a variety of cancer lines including breast cancer, cervical carcinoma, and colorectal carcinoma, and typically results in increased migration, invasion, and metastasis (1). Accordingly, Snail expression is also correlated with drug resistance and tumor recurrence (1-5). Chemical inhibitors that target Snail have shown some promise in reducing or eliminating Snail-induced EMT, increasing E-cadherin expression, and increasing tumor regression (1).
1. Kaufhold, S., & Bonavida, B. (2014). Central role of Snail1 in the regulation of EMT and resistance in cancer: a target for therapeutic intervention. Journal of Experimental & Clinical Cancer Research. https://doi.org/10.1186/s13046-014-0062-0
2. Wang, Y., Shi, J., Chai, K., Ying, X., & Zhou, B. P. (2013). The Role of Snail in EMT and Tumorigenesis. Current Cancer Drug Targets. https://doi.org/10.2174/15680096113136660102
3. Kang, E., Seo, J., Yoon, H., & Cho, S. (2021). The Post-Translational Regulation of Epithelial-Mesenchymal Transition-Inducing Transcription Factors in Cancer Metastasis. International Journal of Molecular Sciences. https://doi.org/10.3390/ijms22073591
4. Seo, J., Ha, J., Kang, E., & Cho, S. (2021). The role of epithelial-mesenchymal transition-regulating transcription factors in anti-cancer drug resistance. Archives of Pharmacal Research. https://doi.org/10.1007/s12272-021-01321-x
5. Baulida, J., Diaz, V. M., & Herreros, A. G. (2019). Snail1: A Transcriptional Factor Controlled at Multiple Levels. Journal of Clinical Medicine. https://doi.org/10.3390/jcm8060757