The multiple roles for Sox2 in stem cell maintenance and tumorigenesis

Abstract

The Sry-containing protein Sox2 initially was known to regulate the self-renewal of the mouse and human embryonic stem cells (ESCs). It is also important for the maintenance of stem cells in multiple adult tissues including the brain and trachea, and it is one of the key transcription factors for establishing induced pluripotent stem cells. Recently, overexpression and gene amplification of Sox2 have been associated with the development of squamous cell carcinoma in multiple tissues such as the lung and esophagus. These different roles for Sox2 involve a complicated regulatory networks consisting of microRNAs, kinases and signaling molecules. While the levels of Sox2 are modulated transcriptionally and translationally, post-translational modification is also important for the various functions of Sox2. In clinics, high levels of Sox2 are correlated with poor prognosis and increased proliferation of cancer stem cells. Therefore targeting Sox2 can be potentially explored for a new therapeutic avenue to treat cancers. This review will focus on the different roles for Sox2 in stem cell maintenance and its oncogenic roles in the context of signal transcription and microRNA regulation. We will also review the main upstream and downstream targets of Sox2, which can be potentially used as therapeutic measures to treat cancer with abnormal levels of Sox2.

Fig. 1

Multiple modifications for regulating Sox2 activities

Fig. 2

Sox2 protein impacted many processes of cancer cells

Fig. 3

Signal transduction pathways were directly or indirectly correlated with Sox2. FGF, IL-4/STAT6 and EGFR-Src-Akt signal pathways directly regulated Sox2 expression, additionally, other potential signal pathways were regulated by Sox2 through its targets or interacting partners.