BAG3 Protein Is Involved in Endothelial Cell Response to Phenethyl Isothiocyanate

Area of Science:

• Cell Biology
• Molecular Biology
• Cancer Research

Background:

• Phenethyl isothiocyanate (PEITC) is a compound found in cruciferous vegetables with demonstrated cancer chemopreventive properties.
• PEITC inhibits tumor growth across various stages in animal models.
• Understanding PEITC's cellular mechanisms in non-cancerous cells is key to its therapeutic potential.

Purpose of the Study:

• To investigate the cellular effects of noncytotoxic concentrations of PEITC in human umbilical vein endothelial cells (HUVECs).
• To elucidate the signaling pathways involved in PEITC-induced cellular changes.
• To determine the role of BAG3 protein in endothelial cell response to PEITC.

Main Methods:

• Treatment of HUVECs with noncytotoxic concentrations of PEITC.
• Analysis of cellular morphology and actin organization.
• Investigation of the PI3K/Akt, Rac1, and JNK signaling pathways.
• Assessment of c-Jun activation and BAG3 protein expression.
• Use of JNK inhibitor (SP600125) to probe signaling pathways.

Main Results:

• PEITC induced morphological changes in HUVECs, including reduced cell volume and altered actin organization.
• PEITC rapidly activated the PI3K/Akt pathway, followed by Rac1 and JNK activation.
• JNK signaling was essential for PEITC-induced actin cytoskeleton modifications.
• PEITC upregulated the expression of BAG3 protein, a cochaperone of heat shock protein 70 (Hsp70).
• BAG3 expression was necessary for the recovery of normal cell size and morphology after PEITC exposure.

Conclusions:

• PEITC triggers specific intracellular signaling cascades in endothelial cells, involving PI3K/Akt, Rac1, and JNK.
• The JNK-c-Jun pathway mediates PEITC's effects on the actin cytoskeleton.
• PEITC induces BAG3 protein expression in HUVECs.
• BAG3 plays a critical role in endothelial cell survival and recovery following stress induced by PEITC, suggesting a novel function in cellular homeostasis.