14-3-3ε is a nuclear matrix protein, and its altered expression and localization are associated with curcumin-induced apoptosis of MG‑63 cells
- Kun Lu
- Gang Rui
- Fan Liu
- Ling Yang
- Xiaoling Deng
- Songlin Shi
- Qifu Li
Published online on: October 30, 2017
Copyright: © Lu et al.
This is an open access article distributed under the terms of Creative Commons Attribution License.
The 14-3-3 protein family may regulates protein interaction, transportation and cellular localization. The regulatory role of 14‑3‑3ε is influenced by its altered localization. In the present study, human osteosarcoma MG‑63 cells were treated with curcumin to induce apoptosis. Subsequently, the altered expression and localization of 14‑3‑3ε and its co‑localization with other apoptosis‑associated proteins during apoptosis was investigated. Analysis of nuclear matrix proteins (NMPs), using two‑dimensional gel electrophoresis with matrix‑assisted laser‑desorption/ionization time‑of‑flight mass spectrometry, revealed that 14‑3‑3ε existed on the nuclear matrix of MG‑63 cells, and its expression was decreased compared with that in control cells following curcumin treatment. In addition, western blot analysis validated that the expression level of 14‑3‑3ε was downregulated during curcumin‑induced apoptosis of MG‑63 cells compared with that in control cells. Using immunofluorescence labeling, it was observed that 14‑3‑3ε was located on the nuclear matrix of MG‑63 cells and the distribution of 14‑3‑3ε on the nuclear matrix was decreased following treatment with curcumin, compared with that in control cells. Double immunofluorescence staining and laser‑scanning confocal microscopy demonstrated that 14‑3‑3ε was co‑localized with B‑cell lymphoma‑2 (Bcl‑2), Bcl‑2‑associated‑X protein, p53 and c‑FOS transcription factor in MG‑63 cells. Furthermore, following treatment with curcumin, these co‑localization regions were decreased. The results of the present study revealed that 14‑3‑3ε is an NMP in MG‑63 cells, and its altered expression and co‑localization with apoptosis‑associated proteins indicated an important function of 14‑3‑3ε in apoptosis of MG‑63 cells. Additional studies are required to investigate the results of the present study.