Gold nanorods are known to be promising agents for photothermal therapy. But the uptake of rod-shaped nanoparticles is lower than their spherical counterpart. It was therefore the objective of this study to select gold nanoparticles (GNPs)-stabilizing agents in order to provide effective penetration into cancer cells.
Materials and methods:
The work was carried out on human ovarian adenocarcinoma SKOV-3 cells. The gold nanorods used in this work had a plasmon resonance peak at 800 nm. The nanoparticles were stabilized by Pluronic® F-127 (PF127), chitosan or polyethylene glycol (PEG); the latter with 6000 Da and 40,000 Da molecular weight. Penetration and intracellular distribution of GNPs were investigated by transmission electron microscopy (TEM) and two-photon luminescence microscopy (2PLM) techniques.
By means of 2PLM and TEM, it could be shown that PF127 facilitates cellular uptake of GNPs very effectively. PF127-stabilized GNPs rapidly (by 1.5 h) penetrated the cell membrane and into the cytoplasm and cell nucleus. GNPs stabilized by chitosan were slowly internalized by the cells in smaller amount. GNPs stabilized by PEG with different molecular weights had difficulty to penetrate into the cells – GNPs were localized on the outer side of the cell membrane after short incubation, and single agglomerates were found in the cells after an extended incubation time.
Nanoparticles stabilized with PF127 were the most effective nanoparticles to penetrate into the cells and were located in the cytoplasm and cell nuclei. Nanoparticles stabilized with chitosan were internalized into cells at a slower rate and in smaller amounts than those stabilized with PF127. Nanoparticles stabilized with PEG6000 Da and PEG40.000 Da were located mainly on cell membranes and could be found in the cytoplasm only after a longer incubation time.
Objective: A flow cytometric approach is proposed to assess the hydrogen peroxide (H2O2) level under chemotherapy action separately in viable and apoptotic tumor cells.
Materials and methods: For studying the involvement of H2O2 in the process of cell death, the genetically encoded fluorescent sensor HyPer2, apoptosis marker PE Annexin V and vital dye 7-AAD were employed. The approach was used for testing the capacity of two cytotoxic drugs, cisplatin and bleomycin, to change the intracellular H2O2 concentration, depending on the stage of cell death.
Results: An increase in HyPer2 fluorescence has been revealed in cells undergoing apoptosis under cisplatin action. This finding indicates that accumulation of H2O2 accompanies the cisplatin-induced apoptotic reaction. HyPer2 response was also revealed in negative to PE Annexin V viable cells which can be explained either by participation of H2O2 in the earliest stages of apoptosis or in a cell response to a non-fatal injury. Under bleomycin action, neither an apoptotic reaction nor changes of fluorescence intensity HyPer2 were detected, allowing one to assume that H2O2 is not involved in the reaction of tumor cells to bleomycin.
Conclusion: The proposed approach can be used for studying the mechanisms of cell death under action of any types of antitumor drugs.
Alteration of cellular energy metabolism is a principal feature of tumor and stem cells. Here we analyze the metabolic interactions between cancer cells and fibroblasts in a co-culture model and the metabolic heterogeneity of tumors and metabolic changes in mesenchymal stem cells during adipogenic differentiation based on the fluorescence of the metabolic cofactors NADH, NADPH, and FAD. We registered a metabolic switch from oxidative phosphorylation to glycolysis with slight acidification of the cytosol in cancer cells in a co-culture model. In the tumor tissue we detected metabolic heterogeneity with more glycolytic metabolism of cancer cells in the stroma-rich zones. The shift of cellular energy metabolism from glycolysis to oxidative phosphorylation and the activation of lipogenesiswere observed in adipocytes. Data aboutmetabolic alterations in cancer and stemcells are important formonitoring the progression of cancers, the development of anticancer drugs and stemcell therapy.