Identification of a small-molecule targeting PLAGL2 DNA-binding domain inhibits extracellular matrix formation and enhances lenvatinib sensitivity in hepatocellular carcinoma.

The increased stiffness of the extracellular matrix (ECM) is known to promote the progression of hepatocellular carcinoma (HCC). Currently, there are no approved therapies for targeting ECM sensors and remodelers. The objective of this study was to identify the molecular mechanisms underlying the role of Pleomorphic adenoma gene-like 2 (PLAGL2) in HCC ECM remodeling and to formulate compounds that effectively inhibit PLAGL2 transcriptional regulation. Our work revealed that PLAGL2 remodeled the ECM produced by HCC cells via an autocrine mechanism and activated HSCs via a paracrine pathway. Mechanistically, PLAGL2 functioned as a transcriptional regulator of insulin-like growth factor 2 (IGF2) and insulin-like growth factor 1 receptor (IGF1R). IGF2 enhanced ECM remodeling by HCC cells and activated HSCs through the IGF1R-PI3K-Akt signaling pathway. Furthermore, using a computer-aided drug design strategy, a novel compound, DC218, derived from the chemical evolution of cytisine, has been developed for the first time to exhibit specificity as an inhibitor of the PLAGL2 DNA binding domain. DC218 significantly degraded ECM, overcame lenvatinib resistance, and synergistically inhibited HCC. These findings provide mechanistic insight into the role of PLAGL2 in HCC ECM remodeling, as well as suggest a novel strategy for inhibiting ECM and treating HCC.