Construction of IL-6/STAT3 reporter gene system for screening and validation of traditional Chinese medicine monomers inhibiting IL-6/STAT3 signaling pathway

Abstract:

It is important to find monomers of traditional Chinese medicine that can inhibit the activation of IL-6/STAT3 signaling pathway to suppress the growth and deterioration of tumors. A novel expression vector containing STAT3 enhancer sequence and NanoLuc (NLuc) reporter gene sequence was constructed by gene recombination technology, then a cell line expressing NLuc luciferase and regulated by STAT3 was further established. The cell line was used to quantitatively detect the regulatory effects of various traditional Chinese medicine monomers on the IL-6/STAT3 signal pathway. The effects of the traditional Chinese medicine monomers inhibiting the IL-6/STAT3 signal pathway were verified by Western blotting immunoassay and Real-time PCR analysis. By enzyme digestion and DNA sequencing analysis, it showed that the reporter gene expression vector pQCXIP-STAT3-Nluc was constructed successfully. The addition of Interleukin-6 (IL-6), a stimulator of STAT3 transcription factor, to the constructed cell line specifically enhanced the luciferase enzymatic reaction in a dose dependent manner. These results demonstrated that the cell line expressing NLuc luciferase and regulated by STAT3 has been constructed successfully. We used the the cell line screened out dendrobiine and tetrandrine which could significantly inhibit IL-6/STAT3 signal pathway and down-regulated the expression of Bcl-2 and Bcl-x in a dose-dependent manner. In conclusion, we have constructed an efficient reporter gene system to detect the transcriptional activity of STAT3, by which the Chinese medicine monomers inhibiting IL-6/STAT3 signaling pathway were successfully screened out, which has some potential theoretical and practical values.