The Phenoxyphenol Compound diTFPP Mediates Exogenous C₂-Ceramide Metabolism, Inducing Cell Apoptosis Accompanied by ROS Formation and Autophagy in Hepatocellular Carcinoma Cells

• Main Authors: Wen-Tsan Chang (Author), Yung-Ding Bow (Author), Yen-Chun Chen (Author), Chia-Yang Li (Author), Jeff Yi-Fu Chen (Author), Yi-Ching Chu (Author), Yen-Ni Teng (Author), Ruei-Nian Li (Author), Chien-Chih Chiu (Author)
• Format: Book
• Published: MDPI AG, 2021-03-01T00:00:00Z.
• Subjects: article
• Online Access: Connect to this object online.

Summary

Hepatocellular carcinoma (HCC) is a severe disease that accounts for 80% of liver cancers. Chemotherapy is the primary therapeutic strategy for patients who cannot be treated with surgery or who have late-stage HCC. C₂-ceramide is an effective reagent that has been found to inhibit the growth of many cancer types. The metabolism of C₂-ceramide plays a vital role in the regulation of cell death/cell survival. The phenoxyphenol compound 4-{2,3,5,6-tetrafluoro-4-[2,3,5,6-tetrafluoro-4-(4-hydroxyphenoxy)phenyl]phenoxy}phenol (diTFPP) was found to have a synergistic effect with C₂-ceramide, resulting in considerable cell death in the HA22T HCC cell line. diTFPP/C₂-ceramide cotreatment induced a two- to threefold increase in cell death compared to that with C2-ceramide alone and induced pyknosis. Annexin V/7-aminoactinomycin D (7AAD) double staining and Western blotting indicated that apoptosis was involved in diTFPP/C₂-ceramide cotreatment-mediated cell death. We next analyzed transcriptome alterations in diTFPP/C₂-ceramide-cotreated HA22T cells with next-generation sequencing (NGS). The data indicated that diTFPP treatment disrupted sphingolipid metabolism, inhibited cell cycle-associated gene expression, and induced autophagy and reactive oxygen species (ROS)-responsive changes in gene expression. Additionally, we assessed the activation of autophagy with acridine orange (AO) staining and observed alterations in the expression of the autophagic proteins LC3B-II and Beclin-1, which indicated autophagy activation after diTFPP/C₂-ceramide cotreatment. Elevated levels of ROS were also reported in diTFPP/C₂-ceramide-treated cells, and the expression of the ROS-associated proteins SOD1, SOD2, and catalase was upregulated after diTFPP/C₂-ceramide treatment. This study revealed the potential regulatory mechanism of the novel compound diTFPP in sphingolipid metabolism by showing that it disrupts ceramide metabolism and apoptotic sphingolipid accumulation.

Item Description

10.3390/antiox10030394
2076-3921