Objectives/Goals: Metallothioneins (MT) are cysteine-rich proteins that bind metals and regulate oxidative stress. MT2A, the most expressed MT gene, is lost in ~70% of High Grade Serous Ovarian Cancer cases. We hypothesize that MT2A loss disrupts mitochondrial function and metabolism, promoting tumor progression. Methods/Study Population: To explore this, MT2A was knocked down (KD) in CAOV3 HGSOC cells via lentiviral shRNA. KD was confirmed transcriptionally via RT-qPCR and functionally using a nuclei-counting assay, which assesses sensitivity to cadmium chloride (CdCl₂), a cytotoxic heavy metal. Mitochondrial membrane potential (MMP) was assessed via flow cytometry, and oxygen consumption rate (OCR) was measured with Resipher. Clonogenic potential was evaluated by soft-agar colony formation assays. Results/Anticipated Results: MT2A KD cells showed a significant decrease in nuclei count in response to CdCl₂. MMP was reduced in MT2A KD cells, indicating compromised mitochondrial integrity. OCR was significantly decreased in MT2A KD cells, suggesting impaired oxidative phosphorylation. These phenotypes are characteristic features of the Warburg effect, which is a hallmark of aggressive cancers. Soft agar assays revealed that MT2A loss significantly enhanced the cell’s ability to multiply adhesion free from a single cell, a phenotype associated with aggressive oncogenic transformation. Discussion/Significance of Impact: In summary, MT2A loss disrupts mitochondrial dynamics and oxidative metabolism while promoting tumor aggressiveness. These findings support our hypothesis that MT2A plays a key role in regulating mitochondrial homeostasis and may influence metabolic adaptation in HGSOC.
Mina-Abouda et al. (Wed,) studied this question.