Trichlorfon induces apoptosis in SH-SY5Y neuroblastoma cells via the endoplasmic reticulum?
Cheng-Yun Liu1, Ping-An Chang, Yi-Jun Wu
1Laboratory of Molecular Toxicology, State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Datunlu Road, Beijing, PR China.
Abstract:
This study investigated the role of the endoplasmic reticulum pathway in apoptosis induced by trichlorfon in SH-SY5Y human neuroblastoma cells. Flow cytometric analysis demonstrated that trichlorfon and its degradation product dichlorvos-induced apoptosis in a dose-dependent manner and Hoechst 33342 staining experiments revealed trichlorfon/dichlorvos-induced nucleus condensation. Western blot analysis indicated decreased expression of caspase-12 and increased activated caspase-12 in trichlorfon-treated cells compared to a control, suggesting that trichlorfon may induce apoptosis in SH-SY5Y partly via the endoplasmic reticulum. Intracellular Ca(2+) level ([Ca(2+)](i)) in SH-SY5Y cells increased after treatment with trichlorfon but was significantly reduced by pre-treatment with a combination of a calcium channel blocker, an inositol trisphosphate receptor inhibitor, and a ryanodine receptor inhibitor. Percent apoptosis and activated caspase-3 and caspase-12 decreased in pre-treated cells compared to those treated with trichlorfon alone. Trichlorfon-induced apoptosis was also inhibited by the protein kinase C activator, phorbol 12-myristate 13-acetate (PMA). These results suggest that endoplasmic reticulum stress, which is related to calcium, may be involved in the cytotoxicity of trichlorfon.
Insights
Trichlorfon induces apoptosis in human neuroblastoma cells by damaging the endoplasmic reticulum pathway, involving calcium signaling. This cellular damage was dose-dependent and mitigated by specific inhibitors.
Area of Science:
- Neuroscience
- Cell Biology
- Toxicology
Background:
- Trichlorfon is an organophosphate pesticide with known neurotoxic effects.
- The endoplasmic reticulum (ER) plays a crucial role in cellular homeostasis and apoptosis.
- Investigating the specific mechanisms of trichlorfon-induced neurotoxicity is vital for understanding its health risks.
Purpose of the Study:
- To elucidate the role of the endoplasmic reticulum pathway in trichlorfon-induced apoptosis in SH-SY5Y human neuroblastoma cells.
- To examine the involvement of intracellular calcium levels and specific signaling pathways in trichlorfon toxicity.
Main Methods:
- Flow cytometry to assess apoptosis and nucleus condensation.
- Western blot analysis to evaluate caspase-12 expression.
- Measurement of intracellular calcium levels ([Ca(2+)](i)).
- Inhibition studies using calcium channel blockers, receptor inhibitors, and protein kinase C activators.
Main Results:
- Trichlorfon and dichlorvos induced apoptosis and nucleus condensation in a dose-dependent manner.
- Trichlorfon treatment altered caspase-12 expression and activation, indicating ER stress.
- Increased intracellular calcium levels were observed, which were reduced by specific inhibitors.
- Pre-treatment with inhibitors significantly reduced apoptosis and caspase activation.
Conclusions:
- Trichlorfon induces apoptosis in SH-SY5Y cells, partly through endoplasmic reticulum stress.
- Calcium signaling is implicated in trichlorfon-induced cytotoxicity.
- Targeting ER stress and calcium pathways may offer therapeutic strategies against trichlorfon neurotoxicity.
