1,1-bis(3'-indolyl)-1-(p-substituted phenyl)methanes decrease mitochondrial membrane potential and induce apoptosis...

Area of Science:

• Biochemistry
• Molecular Biology
• Cancer Research

Background:

• 1,1-Bis(3'-indolyl)-1-(p-substituted phenyl)methanes, including DIM-C-pPhtBu, are known peroxisome proliferator-activated receptor gamma (PPARgamma) agonists.
• However, the specific mechanisms of DIM-C-pPhtBu's effects on endometrial cancer cells require further elucidation.

Purpose of the Study:

• To investigate the mechanism of DIM-C-pPhtBu-induced apoptosis in human HEC1A endometrial cancer cells.
• To determine if the observed effects are mediated through PPARgamma or other cellular pathways.

Main Methods:

• Cell viability assays and apoptosis marker analysis (cytochrome c release, caspase activation, endonuclease G translocation).
• Mitochondrial membrane potential (MMP) assessment.
• Inhibition studies using atractyloside (Atra) to probe the mitochondrial permeability transition pore complex (PTPC) and adenine nucleotide transporter (ANT) proteins.
• Eosin-5-maleimide (EMA) alkylation assays and ATP/ADP exchange measurements in isolated mitochondria.

Main Results:

• DIM-C-pPhtBu induced apoptosis in HEC1A cells independently of PPARgamma.
• The compound decreased MMP, promoted cytochrome c and endonuclease G release, and activated caspases.
• DIM-C-pPhtBu's pro-apoptotic effects were inhibited by atractyloside, indicating PTPC targeting.
• Differential effects of DIM-C-pPhtBu and atractyloside on ANT protein alkylation and ATP/ADP exchange suggest distinct binding sites on ANT.

Conclusions:

• DIM-C-pPhtBu exhibits receptor-independent pro-apoptotic activity in endometrial cancer cells.
• This activity is linked to novel mitochondriotoxic effects involving inner mitochondrial adenine nucleotide transporter (ANT) proteins.
• The findings reveal a new mechanism of action for DIM-C-pPhtBu, targeting the PTPC via ANT proteins.