Artesunate and cisplatin synergistically inhibit HNSCC cell growth and promote apoptosis with artesunate‑induced decreases in Rb and phosphorylated Rb levels

In the treatment of head and neck cancer, cisplatin is often used as a therapeutic agent; however, its efficacy is limited and it can cause renal dysfunction as an adverse effect. For this reason, the use of cisplatin is limited in elderly patients with reduced renal function. Recently, artemisinin, which was developed as an antimalarial drug, was found to have antitumor effects and is effective in combination with other anticancer drugs. In the present study, the antitumor effects of artemisinin and its derivatives as well as their combination with cisplatin and iron on head and neck squamous cell carcinoma cell lines, were investigated. Cell viability was determined by a cell viability assay, the cell cycle was analyzed by flow cytometry, cell death was assessed with annexin V and propidium iodide staining, and western blotting was used to analyze retinoblastoma protein (Rb), phosphorylated (p-)Rb, and other cell cycle-associated molecules. A total of four artemisinin compounds were examined and it was found that artesunate and dihydroartemisinin had a significant inhibitory effect on growth. It was also identified that the combination of artesunate, cisplatin, and iron inhibited cell proliferation and caused S/G2-M cell cycle arrest. In addition, western blotting of Rb, a molecule involved in the cell cycle, showed that artesunate induced the loss of not only Rb but also p-Rb. These results suggested that artesunate is a useful drug in combination with cisplatin.