IGF2BP1 over-expression in skin squamous cell carcinoma cells is essential for cell growth

The present study examined expression and potential functions of insulin-like growth factor 2 mRNA-binding protein 1 (IGF2BP1) in human skin squamous cell carcinoma (SCC). We show that IGF2BP1 mRNA and protein expression levels were upregulated in established (A431 line) and primary human skin SO: cells. Its expression was also increased in human skin SCC tissues, as compared to the normal skin tissues: In skin SCC cells, IGF2BP1 silencing or CRISPR/Cas9 knockout decreased levels of IGF2BP1-stablized mRNAs, including IGF2, CD44, Glil and Myc. Furthermore, skin SCC cell survival and proliferation were inhibited by:IGF2BP1 silencing/knockout. Conversely, forced over-expression of IGF2BP1 further promoted A431 cell. survival and proliferation. Furthermore, siRNA-mediated knockdown of IGF2BP1-bound long non-coding RNA THOR (Lnc-THOR) similarly depleted IGF2BP1-dependent mRNAs, causing inhibition on A431 cell survival and proliferation. In vivo, IGF2BP1 silencing or knockout inhibited A431 tumor xenograft growth in mice. Together, we conclude that IGF2BP1 over-expression in skin SCC cells is essential for cell growth. (C) 2018 Elsevier Inc. All rights reserved.