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Updated: Oct 19, 2025
In Vivo Assessment of Alveolar Macrophage Efferocytosis Following Ozone Exposure
Published on: October 22, 2019
Ozone induces BEL7402 cell apoptosis by increasing reactive oxygen species production and activating JNK
Shuiying Tang1, Bihong Xu2, Jincheng Li1
1Division of Vascular and Interventional Radiology, Department of General Surgery, Nanfang Hospital, Southern Medical University, Guangzhou, China.
Background:
Oxidative stress is an important factor in the modulation of both tumorigenesis and anticancer responses. Ozone (O3) is a strong oxidant that causes redox reactions and exerts anticancer effects in various types of cancer cells. However, the pathways involved in O3-induced cell death are not well understood.
Methods:
In vitro human hepatocellular carcinoma (HCC) BEL7402 cells were treated with various O3 concentrations to evaluate O3 cytotoxicity by Cell Counting Kit-8 (CCK-8) assay and flow cytometry. The regulatory mechanisms were analyzed by western blot analysis. In vivo, an HCC model was established to evaluate the inhibition of HCC with O3 treatment.
Results:
In vitro cells treated with O3 exhibited a round and small morphology with nuclear shrinkage and fragmentation. The CCK-8 assay confirmed the potent cytotoxic activity of O3 against BEL7402 cells (IC50 value of 5 µg/mL). Acridine orange/ethidium bromide (AO/EB) staining revealed apoptosis of BEL7402 cells after O3 treatment. Flow cytometry analysis showed that S phase cell cycle arrest and apoptosis increased with O3 exposure. In addition, O3 exposure reduced the mitochondrial membrane potential (ΔΨm) and induced reactive oxygen species (ROS) accumulation. Western blot analysis showed that O3 exposure reduced B-cell lymphoma 2 (BCL-2) expression and increased cleaved poly ADP-ribose polymerase (PARP), cytochrome C (Cyt-C), caspase-3, caspase-9, and p-JNK expression. In vivo, treatment with intratumor injection O3 (20 µg/mL) inhibited HCC growth.
Conclusions:
Overall, our findings showed that O3 induces BEL7402 cell apoptosis via the intrinsic mitochondria-dependent pathway. Therefore, O3 has therapeutic potential for HCC.
Insights
Ozone (O3) effectively induces apoptosis in hepatocellular carcinoma (HCC) cells by triggering the intrinsic mitochondrial pathway. This study highlights ozone
Area of Science:
- Oncology
- Biochemistry
- Cell Biology
Background:
- Oxidative stress influences cancer development and treatment responses.
- Ozone (O3), a potent oxidant, exhibits anticancer properties.
- Mechanisms of O3-induced cancer cell death require further elucidation.
Purpose of the Study:
- To investigate the cytotoxic effects and underlying mechanisms of ozone (O3) on human hepatocellular carcinoma (HCC) cells.
- To evaluate the therapeutic potential of O3 in an in vivo HCC model.
Main Methods:
- In vitro treatment of BEL7402 HCC cells with varying O3 concentrations.
- Cytotoxicity assessed via Cell Counting Kit-8 (CCK-8) and flow cytometry.
- Apoptosis, cell cycle, mitochondrial potential, and protein expression analyzed.
- In vivo HCC model used to assess O3 treatment efficacy.
Main Results:
- O3 induced characteristic apoptotic morphology in BEL7402 cells.
- O3 demonstrated potent cytotoxicity (IC50 = 5 µg/mL) and induced apoptosis and S phase arrest.
- O3 reduced mitochondrial membrane potential, increased reactive oxygen species (ROS), and modulated apoptosis-related proteins (BCL-2, PARP, caspase-3/9, Cyt-C, p-JNK).
- Intratumoral O3 injection inhibited HCC growth in vivo.
Conclusions:
- Ozone (O3) induces apoptosis in HCC cells through the intrinsic mitochondria-dependent pathway.
- O3 exhibits significant therapeutic potential for treating hepatocellular carcinoma.
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