Pomegranate Extract (POMx) Induces Mitochondrial Dysfunction and Apoptosis of Oral Cancer Cells

Area of Science:

• Biochemistry
• Molecular Biology
• Cancer Research

Background:

• The therapeutic potential of pomegranate polyphenolic extract (POMx) in oral cancer remains underexplored.
• Mitochondrial dysfunction is a critical factor in cancer progression and a potential target for anticancer therapies.

Purpose of the Study:

• To investigate the antiproliferative effects of POMx on human oral cancer cell lines.
• To elucidate the underlying mechanisms of POMx action, focusing on mitochondrial impairment and DNA damage.

Main Methods:

• Treatment of oral cancer cell lines (Ca9-22, HSC-3, OC-2) and normal oral cells (HGF-1) with POMx.
• Assays for cell proliferation, apoptosis (annexin V, Western blotting), ATP levels, and cell cycle distribution (subG1).
• Analysis of mitochondrial membrane potential (MitoMP), mitochondrial superoxide (MitoSOX) generation, mitochondrial mass, mitochondrial DNA (mtDNA) copy number, and biogenesis gene expression.
• Assessment of DNA damage using γH2AX staining and PCR-based mtDNA damage assays.

Main Results:

• POMx demonstrated selective toxicity towards oral cancer cells, inducing ATP depletion, subG1 accumulation, and apoptosis without affecting normal oral cells.
• POMx disrupted mitochondrial membrane potential and increased mitochondrial superoxide generation, correlating with downregulated antioxidant gene expression.
• POMx reduced mitochondrial mass, mtDNA copy number, and mitochondrial biogenesis gene expression.
• POMx induced both nuclear DNA damage (γH2AX) and mitochondrial DNA damage.

Conclusions:

• POMx exhibits significant antiproliferative and pro-apoptotic effects on oral cancer cells.
• The mechanism involves substantial mitochondrial impairment, including disruption of mitochondrial function and integrity.
• POMx-induced DNA damage in both nuclear and mitochondrial genomes contributes to its anticancer activity.