Silver-doped graphene oxide nanocomposite triggers cytotoxicity and apoptosis in human hepatic normal and carcinoma cells

Daoud Ali, Saud Alarifi, Saad Alkahtani, Rafa S Almeer Department of Zoology, College of Science, King Saud University, Riyadh, Saudi Arabia Introduction: Graphene oxide nanoparticles have been widely used in industry and biomedical fields due to their unique physicochemical properties. However, comparative cytotoxicity of silver-doped reduced graphene oxide (rGO–Ag) nanoparticles on normal and cancerous liver cells has not been well studied yet. Materials and methods: This study aimed at determining the toxic potential of rGO–Ag nanocomposite on human liver normal (CHANG) and cancer (HepG2) cells. The rGO–Ag nanocomposite was characterized by using different advanced instruments, namely, dynamic light scattering, scanning electron microscope, and transmission electron microscope. Results: The rGO–Ag nanocomposite reduced cell viability and impaired cell membrane integrity of CHANG and HepG2 cells in a dose-dependent manner. Additionally, it induced reactive oxygen species generation and reduced mitochondrial membrane potential in both cells in a dose-dependent manner. Moreover, the activity of oxidative enzymes such as lipid peroxide, superoxide dismutase, and catalase were increased and glutathione was reduced in both cells exposed to rGO–Ag nanocomposite. Pretreatment with N-acetylcysteine inhibited cytotoxicity and reactive oxygen species generation in CHANG and HepG2 cells exposed to rGO–Ag nanocomposite (50 µg/mL). DNA damage was determined by Comet assay and maximum DNA damage occurred at rGO–Ag nanocomposite (25 µg/mL) for 24 h. It is also valuable to inform that HepG2 cells appear to be slightly more susceptible to rGO–Ag nanocomposite exposure than CHANG cells. Conclusion: This result provides a basic comparative toxic effect of rGO–Ag nanocomposite on hepatic normal and cancerous liver cells. Keywords: oxidative stress, CHANG and HepG2 cells, cytotoxicity, DNA fragmentation, apoptosi

Methotrexate-induced apoptosis in human ovarian adenocarcinoma SKOV-3 cells via ROS-mediated bax/bcl-2-cyt-c release cascading

Gadah AlBasher,1 Abdullah A AlKahtane,1 Saud Alarifi,1 Daoud Ali,1 Mohammed S Alessia,2 Rafa S Almeer,1 Mohamed M Abdel-Daim,3 Nouf K Al-Sultan,1 Ahmed A Al-Qahtani,4,5 Huma Ali,6 Saad Alkahtani1 1Department of Zoology, College of Science, King Saud University, Riyadh, Saudi Arabia; 2Department of Biology, Science College, Al-Imam Muhammad Ibn Saud, Islamic University, Riyadh, Saudi Arabia; 3Department of Pharmacology, Faculty of Veterinary Medicine, Suez Canal University, Ismailia, Egypt; 4Department of Infection and Immunity, Research Center, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia; 5Department of Microbiology and Immunology, Alfaisal University School of Medicine, Riyadh, Saudi Arabia; 6Department of Chemistry Maulana Azad National Institute of Technology, Bhopal, India Introduction: The communication between a substance and a cell may depend on whether the cell is normal or pathological. The disease cells and drug interaction may occasionally overcome beneficial action of the drug; subsequently, it is important to investigate the effect of the drug in both the normal and target cells. This study aimed to evaluate the methotrexate (MTX) antiproliferative effect and explore the mechanistic approach to investigate the cell death index in SKOV-3 ovarian cells during treatment with MTX. Methods: In vitro studies of SKOV-3 cells were examined by tetrazolium assay after exposure to various concentrations of MTX. Moreover, reactive oxygen species (ROS) generation, mitochondrial membrane potential, DNA damage, and AO/EtBr staining morphological analysis of necrotic/apoptotic cells were detected; cellular impairment in mitochondria and DNA was confirmed by JC-1 mitotracker/DAPI, respectively, and cell death pathway markers; bax/bcl-2 were analyzed. Results: A dose-dependent antiproliferative effect of MTX treatment was observed in SKOV-3 cells; the prominent inhibitory concentration was 40 µM of MTX (P<0.01). The growth inhibition rates of the cancer cells reached 24.07% in MTX. The MTX showed increase in ROS generation and mitochondrial depolarization, and DNA integrity cells collectively advocated the apoptotic cell death at higher concentration. In addition, the results of reverse transcription polymerase chain reaction also supported the apoptosis by upregulating the bax and downregulating the bcl-2 (P<0.01). Thus the MTX moderately provokes apoptosis. Conclusion: Our findings suggest that MTX acts on SKOV-3 cancer cells by increasing intracellular ROS levels, leading to DNA damage and altering the MMP along with apoptotic gene upregulation. This mechanism may provide new therapeutic targets to improve tumor treatment. Keywords: methotrexate, MMP, apoptosis, ROS, SKOV-3 cell