Nimotuzumab and irinotecan synergistically induce ROS‐mediated apoptosis by endoplasmic reticulum stress and mitochondrial‐mediated pathway in cervical cancer

Irinotecan (CPT-11), a chemotherapeutic agent used to treat several types of cancer, induces cytotoxic effects on healthy cells. The epidermal growth factor receptor (EGFR) plays a crucial role in various forms of cancer. Nimotuzumab (NmAb), a monoclonal antibody that targets the EGFR, is utilized in some countries to treat malignancies that have an overexpression of EGFR. Yet, there is a lack of literature on the potential anticancer properties of the CPT-11 and NmAb combination on in vitro human cervical cancer cells. This study investigates the apoptosis mode of the CPT-11 and NmAb combination on cervical HeLa cancer cells. The Annexin V/propidium iodide staining examination demonstrated that the combination of CPT-11 and NmAb resulted in a decrease in the number of viable cells and more potent induction of cell apoptosis than the effects of CPT-11 or NmAb alone in HeLa cells. Furthermore, the combined treatment resulted in elevated levels of reactive oxygen species (ROS) and Ca²⁺ compared to the treatment with CPT-11 or NmAb alone. Cells that were pretreated with N-acetyl-l-cysteine, a substance that scavenges ROS, and then treated with CPT-11, NmAb, or a combination of CPT-11 and NmAb exhibited higher numbers of viable cells compared to those treated with CPT-11 or NmAb alone. The combination of CPT-11 and NmAb resulted in significantly higher caspase-3, -8, and -9 activity levels than CPT-11 or NmAb alone, as measured by flow cytometer assay. The combination of CPT-11 and NmAb in HeLa cells resulted in elevated endoplasmic reticulum stress-, mitochondria-, and caspase-mediated proteins compared to treatment with CPT-11 or NmAb alone. According to these observations, NmAb enhances the effectiveness of CPT-11 in fighting cancer by stimulating cell death in the HeLa cells. Therefore, NmAb has the potential to improve the efficacy of CPT-11 as a future cervical cancer treatment in humans.