Oligomeric Proanthocyanidins Reverse Lenvatinib Resistance in Hepatocellular Carcinoma Through ITGA3-Mediated Pathway.

: Oligomeric proanthocyanidins (OPCs) are natural polyphenolic compounds with strong antitumor properties and have gained attention as potential agents to overcome drug resistance. Hepatocellular carcinoma (HCC) remains a major cause of cancer deaths worldwide, and although Lenvatinib is widely used, its effectiveness is limited by acquired resistance. This study explores the potential of OPCs to overcome Lenvatinib resistance in HCC. : To evaluate the potential of OPCs to overcome Lenvatinib resistance in HCC, we established Lenvatinib-resistant Huh-7 and PLC-PRF-5 cell lines and conducted systematic cell culture experiments to assess their antitumor effects. Furthermore, genome-wide transcriptomic profiling, network pharmacology approaches, and pathway enrichment analysis were performed to identify resistance-associated signaling pathways that could serve as therapeutic targets. : The combination of OPCs and Lenvatinib demonstrated a significant synergistic anti-proliferative effect in resistant hepatocellular carcinoma cells, with the most synergistic dose combinations showing Bliss synergy scores exceeding 10. Transcriptomic profiling revealed that the adhesion molecule ITGA3 is a key factor in Lenvatinib resistance and contributes to the acquisition of anoikis resistance. The combination treatment suppressed ITGA3-EGFR-AKT signaling, restored anoikis sensitivity, significantly reduced spheroid formation (fold change = 0.10-0.12; < 0.001), and markedly increased apoptosis (fold change = 2.7-5.0; < 0.001). : This study is the first to demonstrate that OPCs can overcome chemotherapy resistance by targeting the integrin pathway, providing scientific evidence for their potential use as an adjunctive therapy for chemotherapy-resistant HCC.