A novel role of the mitochondrial permeability transition pore in (-)-gossypol-induced mitochondrial dysfunction

Area of Science:

• Biochemistry
• Cell Biology
• Natural Products Chemistry

Background:

• Gossypol, a natural polyphenolic compound, induces various cell death forms in cancer.
• It inhibits Bcl-2, promoting apoptosis in susceptible cells.
• In apoptosis-resistant cancers like glioblastoma, it causes non-apoptotic cell death linked to oxidative stress and mitochondrial issues.

Purpose of the Study:

• Investigate gossypol's impact on mitochondrial function, oxidative stress, and the mitochondrial permeability transition pore (mPTP).
• Utilize the aging model Podospora anserina, which lacks Bcl-2 proteins, for detailed analysis.
• Explore the role of mPTP and autophagy in gossypol's anti-cancer effects.

Main Methods:

• Treatment of Podospora anserina, apoptosis-deficient Bax/Bak double knockout mouse embryonal fibroblasts, and glioblastoma cells with gossypol.
• Assessment of hydrogen peroxide levels and mitochondrial respiration.
• Investigation of cyclophilin D (CYPD)-mediated mPTP opening.

Main Results:

• Gossypol selectively increased hydrogen peroxide levels and impaired mitochondrial respiration in all tested models.
• CYPD-mediated opening of the mPTP was identified as crucial for gossypol-induced mitochondrial dysfunction, autophagy, and cell death.
• These effects were observed in P. anserina during aging and in glioblastoma cells.

Conclusions:

• Gossypol induces mitochondrial dysfunction and cell death via mPTP opening and autophagy.
• These findings provide new insights into the mechanisms of gossypol's anti-cancer activity.
• Gossypol represents a promising natural compound for cancer treatment, particularly in apoptosis-resistant cancers.