Establishment Of A Screening Platform Of Insulin-like Growth-i Factor Rector Inhibitor And Evaluation Of Novel Inhibitors

The insulin-like growth factor receptor (IGF1R) is over-expressed in a wide range of tumor types that contributes to tumor cell proliferation, metastasis, and drug resistance as well. The aim of this study was to establish a sensitive IGF1R inhibitor screening platform and to identify novel IGF1R inhibitors.IGF1R was expressed using the Bac-to-BacTM baculovirus expression system. The screening platform of IGF1R inhibitors were established using enzyme-linked immunosorbent assay (ELISA). The binding profiles of IGF1R with inhibitors was predicted by molecular docking and then subjected to the surface plasmon resonance (SPR) approach. The growth inhibition of cancer cells of IGF1R inhibitor was assessed using the MTT assay. Apoptosis was analyzed by flow cytometry and Western blotting. We expressed the catalytic domain of IGF1R and established IGF1R inhibitor screening platform based on ELISA. Hematoxylin, a naturally small molecule compound, was identified as one of the most remarkable IGF1R inhibitor out of more than 200 compounds library. Molecular simulation predicted the possible binding mode between hematoxylin and IGF1R. SPR assay further confirmed that hematoxylin bound directly to IGF1R with high binding affinity. In HL-60 cancer cells, hematoxylin inactivated the phosphorylation of IGF1R and the downstream signaling, and therefore suppressed cell proliferation. Mechanistic studies revealed that hematoxylin induced apoptosis in HL-60 cells via both extrinsic and intrinsic pathways.We herein established a simple and sensitive ELISA-based screening platform for identifying IGF1R inhibitors. Hematoxylin was identified as a promising IGF1R inhibitor with effective antitumor activity and deserved further investigation.