Doxorubicin Inhibits Phosphatidylserine Decarboxylase and Modifies Mitochondrial Membrane Composition in HeLa Cells

Area of Science:

• Biochemistry
• Cell Biology
• Pharmacology

Background:

• Doxorubicin (DXR) is a cornerstone chemotherapy agent.
• Its primary mechanism involves DNA intercalation and topoisomerase II inhibition.
• Limited research exists on DXR's mitochondrial effects, particularly concerning cardiac toxicity.

Purpose of the Study:

• To investigate the impact of DXR on mitochondrial membrane composition in human cancer cells.
• To elucidate the specific molecular targets and mechanisms underlying DXR's mitochondrial effects.
• To determine if DXR's mitochondrial alterations are specific compared to other topoisomerase II inhibitors.

Main Methods:

• Analysis of mitochondrial membrane composition in DXR-treated human cancer cells.
• Investigated the role of phosphatidylserine decarboxylase (PSD) in DXR-induced membrane changes.
• Assessed DXR localization within mitochondria and its uptake kinetics.
• Compared DXR's effects with other topoisomerase II inhibitors.

Main Results:

• DXR significantly altered mitochondrial membrane composition, specifically the phosphatidylserine (PS)/phosphatidylethanolamine (PE) ratio.
• DXR was found to inhibit phosphatidylserine decarboxylase (PSD) activity.
• DXR rapidly localized to mitochondria, leading to bioenergetic impairment and cell death.
• Other topoisomerase II inhibitors did not induce similar mitochondrial membrane alterations.

Conclusions:

• DXR specifically targets and inhibits PSD, leading to mitochondrial membrane remodeling.
• This PSD inhibition contributes to DXR's bioenergetic impairment and cell death in cancer cells.
• PSD represents a novel molecular target for DXR, potentially influencing its anti-cancer efficacy and toxicity profile.