Regulation of mitochondrial dynamics in 2-methoxyestradiol-mediated osteosarcoma cell death

Abstract

Osteosarcoma (OS) is one of the most malignant tumors of childhood and adolescence. Research on mitochondrial dynamics (fusion/fission) and biogenesis has received much attention in last few years, as they are crucial for death of cancer cells. Specifically, it was shown that increased expression of the cytoplasmic dynamin-related protein 1 (Drp1) triggers mitochondrial fission (division), which activates BAX and downstream intrinsic apoptosis, effectively inhibiting OS growth. In the presented study, human OS cells (metastatic 143B OS cell line) were incubated with 2-methoxyestradiol (2-ME) at both physiologically and pharmacologically relevant concentrations. Cell viability was determined by the MTT assay. Confocal microscopy and western blot methods were applied to examine changes in Drp1 and BAX protein levels. Mitochondrial Division Inhibitor 1, MDIVI-1, was used in the study to further examine the role of Drp1 in 2-ME-mediated mechanism of action. To determine quantitative and qualitative changes in mitochondria, electron microscopy was used. 2-ME at all used concentrations increased mitochondrial fission and induced autophagy in OS cells. At the concentration of 1 µM 2-ME increased the area density of mitochondria in OS cells. Subsequent, upregulated expression of Drp1 and BAX proteins by 2-ME strongly suggests the activation of the intrinsic apoptosis pathway. We further observed 2-ME-mediated regulation of glycolytic state of OS cells. Therefore, we suggest that changes of mitochondrial dynamics may represent a novel mechanism of anticancer action of 2-ME. This finding may open new approaches to improve the efficacy of chemotherapy in the treatment of OS, however, it has to be confirmed by in vivo studies.

Regulation of Mitochondrial Dynamics in Parkinson’s Disease—Is 2-Methoxyestradiol a Missing Piece?

“…However, the activity of ATP via purinergic receptors may mediate tumor promoting activities in prostate and breast cancer cells [204,205]. Based on this discovery, we suggest that anticancer mechanism of 2-ME relies on selective nitro-oxidative stress generation controlling the mitochondrial dynamics, including inhibition of biogenesis and induction of mitochondrial fission, finally resulting in mitophagy and cancer cell death [202].…”

“…In our own studies it has been already demonstrated that 2-ME inhibits mitochondrial biogenesis especially at low physiological concentrations, targeting PGC-1α, COXI, and SIRT3 via nuclear recruitment of nNOS and NO generation [146]. What is more, 2-ME induces DRP-1 expression, leading to inhibition of mitochondrial dynamics and apoptosis of 143B OS cells [202]. The anticancer mechanism of 2-ME and its plausible neurodegenerative features are presented in Figure 1.…”

Induction of 2-hydroxycatecholestrogens O-methylation: A missing puzzle piece in diagnostics and treatment of lung cancer

“…The experimental conditions, such as time and doses, were primarily established based on our previous research [ [32] , [33] , [34] ]. The conditions were subsequently optimized according to lung cancer A549 cell line.…”

“…2-Methoxyestradiol (2-ME) is a major metabolite of E2. Interestingly, in contrast to its parent compound, it has potent anticancer and antiangiogenic activity as confirmed in several in vitro and in vivo studies [ [2] , [3] , [4] , [5] , [6] , [7] , [58] ]. In our previous research we have established that 2-ME might be potentially used as an effective anticancer agent in therapy of osteosarcoma, neuroblastoma and possibly other solid tumors [ [6] , [7] , [8] ].…”

“…Despite numerous studies, the detailed mode of anticancer action of 2-ME has not yet been fully elucidated. Previously, we have evidenced that from the mechanistic point of view 2-ME induces the expression and nuclear translocation of the neuronal nitric oxide synthase (nNOS) leading to local nitro-oxidative stress and DNA damage, which ultimately results in death of actively dividing cells or carcinogenesis [ 2 , 20 ]. We have further proved that 2-ME at both physiological and pharmacological concentrations induces mitochondrial fission and mitophagy resulting in BAX activation and osteosarcoma cell death [ 21 ].…”