Pterostilbene Nanoparticles Downregulate Hypoxia-Inducible Factors in Hepatoma Cells Under Hypoxic Conditions

Abstract

Wen-Sheng Tzeng,1,2 Wei-Lin Teng,3 Pao-Hsien Huang,4 Tzu-Ching Lin,3 Feng-Lin Yen,2,5– 7 Yow-Ling Shiue2 1Department of Radiology, Pingtung Christian Hospital, Pingtung, Taiwan; 2Institute of Biomedical Sciences, National Sun Yat-Sen University, Kaohsiung, Taiwan; 3Graduate Institute of Natural Products, College of Pharmacy, Kaohsiung Medical University, Kaohsiung, Taiwan; 4School of Pharmacy, College of Pharmacy, Kaohsiung Medical University, Kaohsiung, Taiwan; 5Department of Fragrance and Cosmetic Science, College of Pharmacy, Kaohsiung Medical University, Kaohsiung, Taiwan; 6Drug Development and Value Creation Research Center, Kaohsiung Medical University, Kaohsiung, Taiwan; 7Department of Medical Research, Kaohsiung Medical University Hospital, Kaohsiung, TaiwanCorrespondence: Feng-Lin YenDepartment of Fragrance and Cosmetic Science, College of Pharmacy, Kaohsiung Medical University, No.100, Shin-Chuan 1st Road, Sanmin Dist., Kaohsiung City, 80708, TaiwanTel [phone] ext 2028Email [email protected] ShiueInstitute of Biomedical Sciences, National Sun Yat-Sen University, No 70 Lien-Hai Road., Kaohsiung City, 80424, TaiwanTel [phone] ext 5818Email [email protected]: Transcatheter arterial chemoembolization (TACE) is a common clinical treatment for hepatocellular carcinoma (HCC). However, hypoxia induction after treatment might trigger tumor invasiveness and metastasis. Although pterostilbene (PTS) has antitumor effects, its chemoprevention in HepG2 cells under hypoxia has not been investigated yet. In addition, the poor water solubility of raw PTS limits its clinical application. Here, we prepared nanoparticles of PTS (PSN) and compared their antihepatoma activities with those of raw PTS in HepG2 under hypoxic conditions.Materials and Methods: The PTS nanoparticle formulation was prepared by nanoprecipitation, using Eudragit® e100 (EE) and polyvinyl alcohol (PVA) as carriers. We analyzed the physicochemical properties of raw PTS and PSN, including yield, encapsulation efficiency, water-solubility, particle size, morphology, crystalline-to-amorphous transformation, and molecular interaction between PTS and carriers. We also evaluated their antihepatoma activities under hypoxia treatment in HepG2 cells, including cell viability, hypoxia, and apoptosis.Results: The yield and encapsulation efficiency of PSN were 86.33% and > 99%, respectively. The water solubility and drug release of PTS were effectively improved after nanoprecipitation corresponding to the reduction in particle size, amorphous transformation, and formation of hydrogen bonding with carriers. PSN had a better cytotoxic effect than raw PTS in HepG2 under pre- and post-hypoxia conditions. In addition, hypoxia- and apoptosis-related proteins in HepG2 cells under two different hypoxic conditions were significantly inhibited by PSN compared with the control group with hypoxia only, except for HIF-1α in the post-hypoxia group. PSN was also significantly better in inhibiting these proteins, except for Bcl2, under pre-hypoxic conditions.Conclusion: Our results suggested that PSN could improve the water solubility and drug release of PTS and enhance the efficacy of HCC treatment under hypoxic conditions.Keywords: hepatocellular carcinoma, hypoxia, transcatheter arterial chemoembolization

Keywords

• hepatocellular carcinoma
• hypoxia
• transcatheter arterial chemoembolization