RESUMO
Hepatocellular carcinoma (HCC) is one of the most malignant human cancers, with a high mortality rate worldwide. Within an HCC tumor, cancer stem cells (CSCs) are responsible for tumor maintenance and progression and may contribute to resistance to standard HCC treatments. Previously, we characterized CD133+ cells as CSCs in primary HCC and identified chromenopyrimidinone (CPO) as a novel therapeutic for the effective treatment of CD133+ HCC. However, the biological function and molecular mechanism of CD133 remain unclear. Epigenetic alterations of CSCs have impacts on tumor initiation, progression, and therapeutic response. Here, we found that pharmacological and genetic depletion of CD133 in HCC attenuated the activity of DNA methyltransferases via control of DNMT3B stabilization. Genes were ranked by degree of promoter hypo/hyper methylation and significantly differential expression to create an "epigenetically activated by CPO" ranked genes list. Through this epigenetic analysis, we found that CPO treatment altered DNA methylation-mediated oncogenic signaling in HCCs. Specifically, CPO treatment inhibited Adenylyl cyclase-associated protein 1 (CAP1) expression, thereby reducing FAK/ERK activity and EMT-related proteins in HCC. Moreover, CPO improved the efficacy of sorafenib by inhibiting CAP1 expression and FAK/ERK activation in sorafenib-resistant HCC. These novel mechanistic insights may ultimately open up avenues for strategies targeting DNA methylation in liver cancer stem cells and provides novel therapeutic function of CPO for the effective treatment of sorafenib-resistant HCC.