AVJ16 inhibits IGF2BP1 in lung adenocarcinomas and prevents tumor growth in mice
Igf2bp1 is an oncofetal RNA binding protein that is expressed in a wide variety of tumors.  We have recently described a small molecule inhibitor of Igf2bp1, termed AVJ16, that prevents binding of the protein to its RNA targets by directly associating with the protein.  Here, using a multi-omics approach, we have analyzed the effects of this inhibition on RNA binding (by eCLIP), RNA expression (by RNAseq), and protein expression (by mass spectrometry).  RNAs encoding members of several pro-oncogenic signalling pathways, including Hedgehog, Wnt, and PI3K-Akt, are downregulated by AVJ16 treatment, with a high correlation between reduced Igf2bp1 binding directly to the RNA, reduced expression levels of the RNA, and reduced protein expression.  AVJ16 treatment of lung adenocarcinoma (LUAD) cells in culture causes a strong reduction in proliferation, colony formation, invasion, and spheroid growth while enhancing apoptosis and cell death.  All of these effects are limited to cells expressing Igf2bp1. Chemoresistance has also been positively correlated with Igf2bp1 expression in cancer cells.  LUAD cells treated with AVJ16 show a pronounced reduction in vital dye efflux, considered to be a proxy for enhanced chemosensitivity.  In syngeneic LUAD xenografts in mice, IP injection of AVJ16 prevents growth of tumors, and incubation with AVJ16 induces cell death in human organoids from Igf2bp1-expressing LUADs but not from healthy lung tissue.  Taken together, these results suggest that AVJ16 is a promising candidate for mono- and/or adjuvant precision therapy directed against tumors expressing Igf2bp1. Overall design: To elucidate the mechanisms of action of AVJ16 as an inhibitor of IGF2BP1, we assessed the effects of AVJ16 treatment on lung adenocarcinoma (LUAD). A comprehensive RNA sequencing analysis was conducted to identify alterations in RNA expression, H1299 cell line were treated for 48 hour thereby revealing the inhibitor's widespread impact on RNA expression.