Regulation of apoptosis through bcl-2/bax proteins expression and DNA damage by nano-sized gadolinium oxide

Saud Alarifi,1 Huma Ali,2 Saad Alkahtani,1 Mohammed S Alessia3 1Department of Zoology, College of Science, King Saud University, Riyadh, Saudi Arabia; 2Department of Chemistry, Maulana Azad National Institute of Technology Bhopal, MP, India; 3Department of Biology, Faculty of Science, Al-Imam Muhammad Ibn Saud Islamic University, Riyadh, Saudi Arabia Abstract: Gadolinium oxide (Gd2O3) nanoparticles (GNPs) are applied in industrial products, for example, additives, optical glass, and catalysis. There are various suggestions of metal nanoparticles paradigm but the underlying basic mechanism about the toxicity of metal nanoparticles, for example GNPs, remains unclear. This experiment was done to measure the effective toxicity of GNPs (10, 25, 50, and 100 µg/mL) over 24 and 48 h and to evaluate toxicity mechanism in human neuronal (SH-SY5Y) cells. GNPs produced reactive oxygen species (ROS), as evaluated by 2', 7'-dichlorodihydrofluorescein diacetate. Due to incorporation into cells, GNPs generated ROS in a concentration- and time-dependent manner. To determine the toxicity of GNP mechanism related to ROS, we also found chromosome condensation and dysfunction of mitochondrial membrane potential (MMP) after exposure of GNPs. Furthermore, the increased cell apoptosis rate and DNA fragmentation were closely related to the increased dose and exposure duration of GNPs in SH-SY5Y cells. The reduction in MMP with a simultaneous increase in the expression of bax/bcl2 gene ratio indicated that mitochondria-mediated pathway involved in GNPs induced apoptosis. Thus, our finding has provided valuable insights into the probable mechanism of apoptosis caused by GNPs at in vitro level. Keywords: GNPs, SH-SY5Y cells, apoptosis, ROS, DNA fragmentatio

Is extended-field concurrent chemoradiation an option for radiologic negative paraaortic lymph node, locally advanced cervical cancer?

Mushabbab Al Asiri,1 Mutahir A Tunio,1 Reham Mohamed,2 Yasser Bayoumi,2 Abdulrehman Alhadab,1 Rasha M Saleh,3 Muhannad Saud AlArifi,1 Abdelaziz Alobaid4 1Radiation Oncology, Comprehensive Cancer Center, King Fahad Medical City, Riyadh, Saudi Arabia; 2Radiation Oncology, National Cancer Institute, Cairo University, Cairo, Egypt; 3Medical Oncology, Comprehensive Cancer Center, King Fahad Medical City, Riyadh, Saudi Arabia; 4Women's Specialized Hospital, King Fahad Medical City, Riyadh, Saudi ArabiaBackground: The aim was to evaluate whether extended-field concurrent chemoradiation (EF-CCRT) leads to results better than those obtained by standard whole-pelvis concurrent chemoradiation (WP-CCRT) in locally advanced cervical cancer with radiologic negative paraaortic lymph nodes (PALNs).Patients and methods: A total of 102 patients with histopathologically proven squamous cell carcinoma, adenocarcinoma, or adenosquamous cell carcinoma, and radiologic negative PALN locally advanced cervical cancer, stage IIB-IVA, were accrued between July 2007 and April 2008 and were randomly assigned to WP-CCRT (50 patients) or EF-CCRT (52 patients), followed by high-dose rate brachytherapy. Data regarding the safety profile, response rates, and occurrence of local, PALN, or distant failure were recorded.Results: During a median follow-up time of 60 months (18–66), 74/102 patients completed the treatment protocol and were analyzed. Overall PALN, distant-metastasis control, disease-free survival, and overall survival rates were 97.1%, 86.9%, 80.3%, and 72.4% in EF-CCRT respectively in comparison with WP-CCRT (82.1%,74.7%, 69.1%, and 60.4%), with P-values of 0.02, 0.03, 0.03 and 0.04 respectively. No difference in acute toxicity profile was seen between the groups, and late toxicities were mild and minimal.Conclusion: Prophylactic EF-CCRT can be a reasonable option in patients with locally advanced cervical cancer with radiologic positive pelvic lymph nodes and radiologic negative PALN.Keywords: prophylactic extended field radiation therapy, concurrent chemotherap

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

Retinoic acid synergizes ATO-mediated cytotoxicity by precluding Nrf2 activity in AML cells

Background: Standard therapy for acute promyelocytic leukaemia (APL) includes retinoic acid (all-trans retinoic acid (ATRA)), which promotes differentiation of promyelocytic blasts. Although co-administration of arsenic trioxide (ATO) with ATRA has emerged as an effective option to treat APL, the molecular basis of this effect remains unclear. Methods: Four leukaemia cancer human models (HL60, THP-1, NBR4 and NBR4-R2 cells) were treated either with ATO alone or ATO plus ATRA. Cancer cell survival was monitored by trypan blue exclusion and DEVDase activity assays. Gene and protein expression changes were assessed by RT-PCR and western blot. Results: ATO induced an antioxidant response characterised by Nrf2 nuclear translocation and enhanced transcription of downstream target genes (that is, HO-1, NQO1, GCLM, ferritin). In cells exposed to ATO plus ATRA, the Nrf2 nuclear translocation was prevented and cytotoxicity was enhanced. HO-1 overexpression reversed partially the cytotoxicity by ATRA-ATO in HL60 cells. The inhibitory effects of ATRA on ATO-mediated responses were not observed in either the ATRA-resistant NB4-R2 cells or in NB4 cells pre-incubated with the RARα antagonist Ro-41-52-53. Conclusions: The augmented cytotoxicity observed in leukaemia cells following combined ATO-ATRA treatment is likely due to inhibition of Nrf2 activity, thus explaining the efficacy of combined ATO-ATRA treatment in the APL therapy. © 2014 Cancer Research UK