Cancer-associated fibroblast-derived SPP1 is a potential target for overcoming sorafenib and lenvatinib resistance in hepatocellular carcinoma

Background: Cancer-associated fibroblasts (CAFs) play an important role in the induction of chemo-resistance. The objectives of this study were to clarify the mechanism underlying CAF-mediated sorafenib/lenvatinib resistance and identify a novel therapeutic target to overcome resistance to sorafenib/ lenvatinib in hepatocellular carcinoma (HCC). Material and methods: Whole transcriptome sequencing (WTS) data of nine pairs of CAFs and para-cancer fibroblasts (PAFs) were analyzed to identify key molecules that induce resistance to tyrosine kinase inhibitors (TKIs). in vitro and In vivo experiments were performed to validate selected targets and related mechanisms. Plasma SPP1 expression levels prior to sorafenib/lenvatinib treatment as well as progression-free survival (PFS) and overall survival (OS) of an advanced HCC cohort (n = 42) were evaluated using Kaplan-Meier analysis. Results: Co-culturing CAFs and HCC cells significantly reduced the responsiveness of HCC cells to sorafenib/lenvatinib, in vitro and in vivo. Systematic integrative analysis of the WTS data of CAFs/PAFs and publicly available gene expression data indicated that CAF-derived SPP1 (CAF-SPP1) was suitable for use as a candidate molecule to induce sorafenib/ lenvatinib resistance. An evaluation of the mechanisms involved indicated that CAF-SPP1 increased phosphorylation of PKCɑ, which then activated RAF-ERK1/2-STAT3 and PI3K-AKT-mTOR in HCC cells. SPP1 inhibitors reversed[Author1] CAF-induced sorafenib/lenvatinib resistance in vitro and in vivo. Patients showing high plasma SPP1 prior to sorafenib/lenvatinib treatment exhibited significantly poor PFS (P = 0.005) and OS (P = 0.041). Conclusions: CAF-SPP1 enhances sorafenib/lenvatinib resistance in HCC by alternatively activating oncogenic pathways via PKCɑ phosphorylation. Inhibition of CAF-SPP1 may be utilized as a therapeutic strategy against TKI-resistance in HCC. Plasma SPP1 level prior to TKI treatment shows potential as a promising biomarker for predicting sorafenib/lenvatinib response in advanced HCC patients. No conflict of interest.