[Mechanism of arsenic trioxide-induced apoptosis in hepatic blastoma cells HepG2]
Ding Yu1, Zi-hui Wang, Li-yuan Zhu
1Department of Surgery, Shenzhen Hospital, Beijing University, Shenzhen 518036, China.
Objective:
To investigate the mechanism of arsenic trioxide (As(2)O(3)) induced apoptosis in hepatic blastoma cells HepG2 and its effects on cell nuclear matrix related protein promyelocytic leukaemia (PML).
Methods:
HepG2 cells were cultured in MEM medium and treated with different concentrations of As(2)O(3) for either 24 h or 96 h. In situ terminal deoxynucleotidyl transferase (TdT) labeling (TUNEL) and DNA ladder were applied to detect apoptosis. Confocal microscopy and western blot were performed to observe the expression of PML.
Results:
TUNEL positive apoptotic cells and DNA ladder could be detected in As(2)O(3) treated groups. The expression of PML decreased in HepG2 cells with 2 micro mol/L As(2)O(3), and micropunctates characteristic of PML protein in HepG2 cell nuclei almost disappeared after the treatment of 5 micro mol/L As(2)O(3).
Conclusion:
As(2)O(3) induces HepG2 tumor cell apoptosis in a time- and concentration-dependent manner. As(2)O(3) may degradate the PML protein in HepG2 cell nuclei. The decreased expression of PML is closely correlated with apoptosis. Nuclear matrix associated protein PML could be the target of As(2)O(3) therapy.
Insights
Arsenic trioxide induces apoptosis in liver cancer cells (HepG2) by degrading the promyelocytic leukaemia (PML) protein. This degradation is linked to increased cell death, suggesting PML as a therapeutic target.
Area of Science:
- Molecular Biology
- Cancer Research
- Cellular Toxicology
Background:
- Hepatocellular carcinoma (HCC) remains a significant global health challenge.
- Arsenic trioxide (As(2)O(3)) has shown therapeutic potential in certain cancers.
- The precise mechanisms of As(2)O(3) action in liver cancer cells require further elucidation.
Purpose of the Study:
- To investigate the mechanism of As(2)O(3)-induced apoptosis in HepG2 liver cancer cells.
- To examine the effect of As(2)O(3) on the expression of promyelocytic leukaemia (PML) protein.
Main Methods:
- HepG2 cells were treated with varying concentrations of As(2)O(3) for 24 or 96 hours.
- Apoptosis was assessed using in situ terminal deoxynucleotidyl transferase (TdT) labeling (TUNEL) and DNA ladder assays.
- PML protein expression was analyzed via confocal microscopy and western blot.
Main Results:
- As(2)O(3) treatment resulted in detectable apoptosis in HepG2 cells, evidenced by TUNEL-positive cells and DNA fragmentation.
- A dose-dependent decrease in PML expression was observed with As(2)O(3) treatment.
- Micropunctate structures of PML protein in HepG2 nuclei significantly diminished after exposure to 5 μmol/L As(2)O(3).
Conclusions:
- As(2)O(3) induces apoptosis in HepG2 cells in a time- and concentration-dependent manner.
- As(2)O(3) likely leads to the degradation of PML protein within HepG2 cell nuclei.
- The observed decrease in PML expression correlates with apoptosis, positioning PML as a potential therapeutic target for As(2)O(3) treatment in liver cancer.
