Treatment of hepatocellular carcinoma with autologous platelets encapsulating sorafenib or lenvatinib: A novel therapy exploiting tumor-platelet interactions.

Hepatocellular carcinoma (HCC) activates platelets through the action of adjacent sinusoidal cells. Activated platelets bind to tumor-associated endothelial cells and release growth factors that promote tumor progression. We hypothesized that platelets encapsulated with tumor inhibitors would function as drug carriers for tumor therapy. We propose a therapeutic strategy for HCC using autologous platelets encapsulating multiple tyrosine kinase inhibitors in a rat chemically induced HCC model. Sorafenib or lenvatinib was encapsulated in platelets isolated from tumor-bearing rats in vitro. The rats were divided into groups that received repeated intravenous injections (twice a week for 10 weeks) of the following materials: placebo, sorafenib (SOR), lenvatinib (LEN), autologous platelets, autologous platelets encapsulating sorafenib (SOR-PLT) and autologous platelets encapsulating lenvatinib (LEN-PLT). The therapeutic effect was then analyzed by ultrasonography (US) and histopathological analysis. Histopathological and US analysis demonstrated extensive tumor necrosis in the tumor tissue of SOR-PLT or LEN-PLT, but not in other experimental groups. By liquid chromatography-mass spectrometry, more abundant sorafenib was detected in tumor tissues after SOR-PLT administration than in surrounding normal tissues, but no such difference in sorafenib level was observed with SOR administration. Therefore, the use of autologous platelets encapsulating drugs might be a novel therapeutic strategy for HCC.