ABSTRACT
[This retracts the article DOI: 10.17179/excli2019-1136.].
ABSTRACT
Glioblastoma multiforme (GBM), like the devastating type of astrocytic tumors, is one of the most challenging cancers to treat owing to its aggressive nature. Auraptene, as a prenyloxy coumarin from citrus species, represents antioxidant and antitumor activities; however, the underlying antitumor mechanisms of auraptene against GBM remain unclear. The present study aimed to evaluate the cytotoxic and apoptogenic effects of auraptene, as a promising natural product, and the possible signaling pathways affected in human malignant GBM (U87) cells. Reactive oxygen species (ROS) production significantly decreased in the first 2, and 6 hours after treatment with auraptene however, ROS levels increased in other incubation times (8 and 24 hours), dramatically. N-acetyl-cysteine (NAC) markedly attenuated auraptene-induced ROS production, and consequently reversed auraptene-induced cytotoxicity in 8 and 24 hours after treatment, as well. Induction of apoptosis occurred in the first 24- and 48-hours concentration-dependently. The qRT-PCR showed an up-regulation in p21, CXCL3, and a down-regulation in Cyclin D1 genes expression. Western blot analysis confirmed the up-regulation of the Bax/Bcl-2 ratio protein levels concentration-dependently. Hence, this study collectively revealed that the increase in ROS level is at least one of the mechanisms associated with auraptene-induced GBM cell toxicity as well as the induction of apoptosis through Bax/Bcl-2 modulation and genes expression involved that contribute to the cytotoxicity of auraptene in U87 cells. So, auraptene might be utilized as a potential novel anti-GBM agent after further studies.
ABSTRACT
Epithelial-mesenchymal transition (EMT) is a critical process in the development of many tissues and organs in multicellular organisms that its important role in the pathogenesis of metastasis and tumor cell migration has been firmly established. Decreased adhesive capacity, cytoskeletal reorganization, and increased mobility are hallmarks of the EMT. Several molecular mechanisms promote EMT, Including regulation of the levels of specific cell-surface proteins, ECM-degrading enzymes, and altering the expression of certain transcription factors and microRNAs. EMT process is modulated through multiple signaling pathways including the AKT/mTOR pathway. AKT is a key component in numerous processes which was recently shown to regulate the EMT through suppression of the expression of E-cadherin via EMT transcription factors. On the other hand, mTOR complexes can also regulate the EMT through the regulation of cell's actin cytoskeleton by altering the PKC phosphorylation state and direct phosphorylation and activation of Akt. Here we review the effect of AKT and mTOR on EMT and consequently metastasis and cell motility.
Subject(s)
Epithelial-Mesenchymal Transition/physiology , Proto-Oncogene Proteins c-akt/physiology , TOR Serine-Threonine Kinases/physiology , Cell Movement/physiology , Humans , Neoplasm Metastasis/pathology , Signal TransductionABSTRACT
OBJECTIVE: Glioblastoma multiforme (GBM) is the deadliest type of primary brain tumors, and the survival of patients is estimated to be only about one year. This study, for the first time, investigated the cytotoxic effects of auraptene on U87 GBM cell line. MATERIALS AND METHODS: The cellular toxicity was measured by the MTT assay following 24 and 48-hr treatment with different concentrations of auraptene (0-400µg/ml). Apoptosis was evaluated by sub-G1 peak in cell cycle analysis of propidium-iodide- stained nuclei. Moreover, to determine the Bax, Bcl-2, MCP-1, NF-κB, IL-1ß, and p53 genes expression, we used real-time polymerase chain reaction (RT-PCR). RESULTS: The results revealed that auraptene reduced the viability of U87 cells concentration- and time-dependently with IC50 values of 108.9 and 79.17µg/ml obtained for 24 and 48-hr treatments, respectively. Also, sub-G1 population was significantly increased following 24 (p<0.05 and p<0.001) and 48 (p<0.001) hours of treatment. The quantitative real-time RT-PCR showed an up-regulation in Bax, NF-κB, IL-1ß, and p53 but a down-regulation in MCP-1 and Bcl-2 genes expression. CONCLUSION: This study showed that auraptene triggered apoptosis probably through Bax/Bcl-2 regulation, blocked cell cycle progression and inhibited proliferation in U87 GBM cells. Taken together, auraptene can be utilized as an effective natural medicine against GBM, after complementary studies.
