RESUMEN
Following the publication of this paper, it was drawn to the Editors' attention by a concerned reader that the cell invasion and migration assay data shown in Fig. 6 and the cell proliferation assay experiments shown in Fig. 2 were strikingly similar to data appearing in different form in other articles by different authors; furthermore, in Fig. 2, for the '10 mM metformin' experiment, certain of the glioma cells appeared to be strikingly similar to other cells contained within the same data panels. Owing to the fact that the contentious data in the above article had already been published elsewhere or were under consideration for publication prior to its submission to Molecular Medicine Reports, and owing to concerns with the authenticity of certain of the data, the Editor has decided that this paper should be retracted from the Journal. The authors were asked for an explanation to account for these concerns, but the Editorial Office did not receive a reply. The Editor apologizes to the readership for any inconvenience caused. [Molecular Medicine Reports 20: 887894, 2019; DOI: 10.3892/mmr.2019.10369].
RESUMEN
The purpose of the present study was to determine the effects of metformin on the inhibition of proliferation, apoptosis, invasion and migration of A172 human glioma cells in vitro and determine the underlying mechanism. The effects of metformin at different concentrations (0, 0.1, 1 and 10 mmol/l) on the inhibition of A172 cell proliferation were detected using a 3(4,5dimethylthiazol2yl)2,5diphenyltetrazolium bromide assay. Cell apoptosis was detected by flow cytometry. Caspase3 activity was analyzed by spectrophotometry. The invasion and migration of cells were detected by Transwell assays. The levels of Bcl2associated X protein (Bax), Bcell lymphoma 2 (Bcl2), AMPactivated protein kinase (AMPK), phosphorylated(p)AMPK and mechanistic target of rapamycin (mTOR) protein expression were detected by western blot analysis, and changes in the malondialdehyde (MDA) content and activity of superoxide dismutase (SOD) were determined. Compared with the control group, metformin significantly increased the inhibition of proliferation and apoptosis, and significantly reduced the invasion and migration of A172 cells in dose and timedependent manners (P<0.05). In addition, compared with the control group, metformin significantly enhanced the activity of caspase3, increased the expression of AMPK/pAMPK/Bax proteins and reduced the expression of mTOR/Bcl2 proteins (P<0.05). Metformin increased the MDA content and reduced the activity of SOD in a dosedependent manner (P<0.05). Metformin may inhibit glioma cell proliferation, migration and invasion, and promote its apoptosis; the effects may be associated with the AMPK/mTOR signaling pathway and oxidative stress.
