Understanding of Benzophenone UV Absorber-Induced Damage and Apoptosis in Human Hepatoma Cells

Abstract

Benzophenone UV absorbers (BPs), a widely used family of organic UV absorbers (UVAs), have attracted considerable attention for their effects on organisms in recent years. Previous research has been unable to illuminate the intricate situation of BP pollution. To address this knowledge gap, we devised a BAPG-chain model that surpasses existing approaches based on biochemical detection, antioxidant defense systems, proteins, and genes to investigate the biological mechanisms of benzophenone-1 (BP-1) and benzophenone-3 (BP-3) within human hepatoma SMMC-7721 cells as model organisms. The BAPG-chain model links the cellular model, molecular level, macroscopic scale, and microscopic phenomena by adopting a global assessment mindset. Our findings indicate that BPs induce apoptosis via the excessive production of reactive oxygen species (ROS), mitochondrial and nuclear damage, and disruption of the antioxidant stress system. Notably, BPs induce apoptosis via alterations in the expression of genes and proteins associated with apoptosis in the mitochondria. Our experimental evidence sheds light on the biological effects of BPs and highlights the need for further research in this area.

Keywords: BAPG-chain model; benzophenone UV absorbers (BPs); biological mechanism; human hepatoma cells.

Figure 1

Diagram of the BAPG-chain model.

Figure 2

The effect of BPs with different concentrations on cell viability and morphology. (a): The effect of BP−1 with different concentrations on cell viability (Lowercase letters a–g denote p < 0.05 as obtained using one-way analysis of variance) (i) Cell viability of 24 h, (ii) Cell viability of 48 h. (b): The effect of BP−3 with different concentrations on cell viability (Lowercase letters a–e denote p < 0.05) (i) Cell viability of 24 h, (ii) Cell viability of 48 h. (c): The effect of BPs with different concentrations on cell morphology (Scale bar: 100 μm).

Figure 3

Changes in mitochondrial membrane potential (MMP) and ultrastructure. (a): The effect of BP-1 on MMP (Scale bar: 100 μm). (b): The effect of BP-3 on MMP (Scale bar: 100 μm). (c): Relative intensity of red/green fluorescence of BPs (Lowercase letters denote p < 0.05). (d): Ultrastructure of cells in the presence of BPs (Scale bar of nuclear: 5.0 μm; Scale bar of mitochondria: 2.0 μm) (The red arrow points to the nucleus, and the blue arrow points to the mitochondria).

Figure 4

RNA sequencing analysis of SMMC-7721 cells after BP intervention. (a): DEGs in different groups. (b): Venn diagrams of significantly DEGs related to mitochondria, oxidative stress, and apoptosis. (c): GO functional analysis of significantly DEGs. (d): KEGG pathway enrichment analysis of significantly DEGs. ((i) Number of DEGs in different groups, (ii) Heat map of DGEs related to mitochondrial function, oxidative stress, and apoptosis).