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Ochratoxin A affects COS cell adhesion and signaling
Antonio Scibelli1, Simona Tafuri, Maria C Ferrante
1Dipartimento di Patologia e Sanità Animale, Università di Napoli Federico II, 80137 Napoli, Italy.
Toxicology and Applied Pharmacology
|October 25, 2003
Summary
Ochratoxin A (OTA) triggers cell death by disrupting cell adhesion and signaling pathways. This mycotoxin reduces key protein phosphorylation, leading to apoptosis and cell detachment in COS cells.
Area of Science:
- Cell Biology
- Toxicology
- Molecular Biology
Background:
- Ochratoxin A (OTA) is a nephrotoxic, carcinogenic, and teratogenic mycotoxin.
- OTA induces apoptosis in a cell-type specific manner at nanomolar concentrations.
Purpose of the Study:
- To elucidate the molecular mechanisms underlying OTA-induced apoptosis.
- To investigate how OTA affects cell adhesion and signaling pathways in COS cells.
Main Methods:
- Analysis of cell adhesion to collagen and fibronectin.
- Measurement of caspase-3 activation to assess apoptosis.
- Western blot analysis to determine tyrosine phosphorylation levels of FAK, paxillin, and Shc isoforms.
Main Results:
- OTA induced apoptosis, evidenced by caspase-3 activation, prior to cell detachment.
- OTA reduced tyrosine phosphorylation of focal adhesion kinase (FAK) and paxillin.
- Down-regulation of FAK preceded OTA-induced apoptosis and cell detachment.
- OTA decreased phosphorylation of Shc isoforms (p66 and p52), potentially impacting c-Src activation.
Conclusions:
- OTA induces apoptosis and cell detachment by interfering with FAK and Shc signaling pathways.
- The dephosphorylation of FAK and paxillin by OTA may result from early down-regulation of Shc isoforms.
- Further research is needed to determine if FAK and Shc signaling converge or diverge in OTA-induced apoptosis.