Comparing proteins linked to preventing mitochondrial and oxidative stress ovarian cancer cells

Abstract

Ovarian cancer is the most fatal gynecological malignancy, with an estimated 12,450 women being expected to die of the disease in 2026. Chemotherapy is the standard treatment for ovarian cancer, but over 70% of patients relapse after treatment. Research shows that cisplatin, a chemotherapy drug, works by causing stress to the mitochondria due to damaging mitochondrial DNA and proteins. This damage disrupts the Electron Transport Chain (ETC), causing large amounts of mitochondrial reactive oxygen species (ROS) to form in the mitochondria, which can lead to oxidative stress and apoptosis. However, the ovarian cancer cell line A2780cis, which is cisplatin resistant, is not affected by cisplatin exposure. Studies have found that cisplatin resistant ovarian cancer cells use various protein pathways to prevent the mitochondrial stress that is triggered by cisplatin. The proteins CHCHD4, LONP1, and SLC25A10, which degrade and prevent the generation of ROS, were analyzed by Western Blot and Immunocytochemistry. It is hypothesized that the cisplatin resistant cell line, A2780cis, would have more of these proteins than the cisplatin sensitive cell line, A2780. This discovery would explain how A2780cis cells are resistant to the stress caused by chemotherapy drugs. To test this theory, western blots were used to validate antibody specificity and to determine if the target proteins were found in the cells. ImageJ, an image analysis software, was used to find the relative density of the bands. Immunocytochemistry was then used to visualize where in the cell the proteins were located. Resulting data suggest that proteins that prevent mitochondrial stress are crucial to ovarian cancer drug resistance.