Mechanisms of oxidative stress, apoptosis, and autophagy involved in graphene oxide nanomaterial anti-osteosarcoma effect

Abstract

BackgroundGraphene and its derivative graphene oxide (GO) have been implicated in a wide range of anticancer effects.PurposeThe objective of this study was to systematically evaluate the toxicity and underlying mechanisms of GO on two osteosarcoma (OSA) cancer cell lines, MG-63 and K7M2 cells.MethodsMG-63 and K7M2 cells were treated by GO (0–50 µg/mL) for various time periods. Cell viability was tested by MTT and Live/Dead assays. A ROS Detection Kit based on DHE oxidative reaction was used for ROS detection. An Annexin V-FITC Apoptosis Kit was used for apoptosis detection. Dansylcadaverine (MDC) dyeing was applied for seeking unspecific autophagosomes. Western blot and Immunofluorescence analysis were used for related protein expression and location.ResultsK7M2 cells were more sensitive to GO compared with MG-63 cells. The mechanism was attributed to the different extent of the generation of reactive oxygen species (ROS). In K7M2 cells, ROS was easily stimulated and the apoptosis pathway was subsequently activated, accompanied by elevated expression of proapoptosis proteins (such as caspase-3) and decreased expression levels of antiapoptosis proteins (such as Bcl-2). A ROS inhibitor (N-acetylcysteine) could alleviate the cytotoxic effects of GO in K7M2 cells. However, the production of ROS in MG-63 cells was probably inhibited by the activation of an antioxidative factor, nuclear factor-E2-related factor-2, which translocated from the cytoplasm to the nucleus after GO treatment, while a nuclear factor-E2-related factor-2 inhibitor (ML385) significantly increased ROS production in MG-63 cells when combined with GO treatment. In addition, autophagy was simultaneously stimulated by characteristic autophagosome formation, autophagy flux, and increased the expression level of autophagy-related proteins (such as LC3I to LC3II conversion, ATG5, and ATG7).ConclusionThis paper proposes various underlying mechanisms of the anticancer effect of GO. The novel synthetic use of GO with an oxidizing agent is the key step for further potential applications in clinical OSA cancer therapy.

Graphene oxide suppresses the growth and malignancy of glioblastoma stem cell-like spheroids via epigenetic mechanisms

“…Moreover, flow cytometry analysis showed that GO induced cell cycle arrest. A previous study reported that graphene derivatives could promote apoptosis in osteosarcoma [31]. Our data showed that GO induced apoptosis Fig.…”

Cytotoxicity and Immune Dysfunction of Dendritic Cells Caused by Graphene Oxide

“…They found that the cytotoxicity was dependent on GO sheet size for NIH 3T3, U87, and A549 cells, while little effect of sheet size on toxicity for RAW 264.7, NB4, and HL60 cell lines. Previous research reported that the production of ROS is one of the important mechanisms for the toxicity of nanoparticles (Khatri et al, 2013;Seabra et al, 2014;Tang et al, 2018). Nanoparticles interfere with oxidative balance of cell and cause oxidative stress to generate reactive oxygen species, such as superoxide, hydroxyl radical, peroxide radical, hydrogen peroxide, and singlet oxygen (Yan et al, 2017;Lu et al, 2019).…”

CoQ10 ameliorates mitochondrial dysfunction in diabetic nephropathy through mitophagy

“…mitoTEMPO (200 μM, Sigma-Aldrich, SML0737) was added for 2 h before glucose treatment to scavenge the mtROS (Chen et al 2018). In addition, pretreatment with the antagonist ML385 (10 μM, Abcam, ab120843) (Tang et al 2018) was done for 2 h every day before CoQ10 administration to inhibit Nrf2.…”