Inhibition of Anaphase-Promoting Complex by Silence APC/CCdh1 to Enhance Radiosensitivity of Nasopharyngeal Carcinoma Cells.

The aim of this study was to investigate the possibility of APC/CCdh1 as a potential therapeutic target in the radiosensitivity of nasopharyngeal carcinoma (NPC) cell CNE-1, and explain the role of APC subunits after silence of Cdh1 combined with radiotherapy. Transfection with Cdh1 shRNA significantly increased the radiosensitivity of CNE-1 cells and the radiation enhancement ratio (RER) of sh-Cdh1 cells was 1.76. Knockdown of Cdh1 in CNE-1 cells increased irradiation induced apoptosis and G2/M phase cell cycle arrest. The levels of CDC20 and CylinB1 increased and the levels of Ku70 and APC3 decreased after irradiation. APC/CCdh1 is involved in regulation of radiosensitivity in human NPC CNE-1 cells. Our study may provide a promising therapeutic strategy for NPC by targeting Cdh1. J. Cell. Biochem. 118: 3150-3157, 2017. © 2016 Wiley Periodicals, Inc.

Functional characterization of TRPM7 in nasopharyngeal carcinoma and its knockdown effects on tumorigenesis.

The aim of this study was to evaluate the association of functional expression of TRPM7 with nasopharyngeal carcinoma (NPC) growth. We examined the correlation of TRPM7 expression with cell growth and proliferation, cell cycle, and apoptosis in vitro in NPC cell lines and NPC tumorigenesis in mice by conducting experiments in mice and by further analyzing the tumor volume and growth. We further explored to see whether there is any positive correlation with the TRPM7 knockdown in NPC cells with their sensitivity to radiation. We found that the functional expression of TRPM7 in nasopharyngeal carcinoma is a critical requirement for physiological processes such as cell cycle, resistance to apoptosis, and cell proliferation. TRPM7 knockdown also enhanced sensitivity to radiotherapy of nasopharyngeal carcinoma. Moreover, we identified TRPM7 as a novel potential regulator of cell proliferation in NPC, through signal transducer and activator of transcription 3 (STAT3)-mediated signaling pathway and other anti-apoptotic factors. TRPM7 and STAT3 activation might be critical for the growth of NPC cells and could be an effective target for treatment of nasopharyngeal carcinoma.

[Interference of long noncoding RNA FOXCUT inhibits epithelial-mesenchymal transformation and induces mitochondrial injury in nasopharyngeal carcinoma cells].

OBJECTIVE: To investigate the effects of RNA interference of long noncoding RNA FOXCUT on epithelial mesenchymal transformation and mitochondrial function in nasopharyngeal carcinoma (NPC) cells. METHODS: FOXCUT expression levels were detected by RT-PCR in tumor tissues and adjacent tissues from 50 patients with NPC and in NP69, CNE1, CNE2, SUNE2, HER2 and 5-8F cell lines. CNE1 cells were transfected with a short hairpin RNA (shRNA) targeting FOXCUT or a negative control RNA construct (shRNA-NC), and the changes in cell proliferation and morphology were assessed with CCK8 assay, clone formation assay and microscopic observation. An immunofluorescence assay was used to examine the vimentin-positive cells, and the levels of SOD, MDA and LDH in the cells were detected. The changes of mitochondrial membrane potential were detected with flow cytometry, and the expression levels of E-cad, N-cad, vimentin, Bax, Bcl-2, caspase-3 and c-Myc in the cells were detected with Western blotting. RESULTS: The expression level of FOXCUT was significantly increased in NPC tissues as compared with the adjacent tissues (P < 0.001). Compared with NP69 cells, CNE1, CNE2, SUNE2, HER2 and 5-8F cells all exhibited significantly increased expressions of FOXCUT (P < 0.001). In CNE1 cells, transfection with FOXCUT shRNA significantly inhibited cell proliferation and clone formation (P < 0.001), and caused obvious changes in cell morphology. FOXCUT knockdown significantly decreased the expressions of N-cad and vimentin, increased E- cad expression and the contents of MDA and LDH (P < 0.05), reduced vimentin- positive cells and the activity of SOD, and caused a shift of red fluorescent cells to green fluorescent cells and an increased percentage of green fluorescent cells. FOXCUT knockdown also resulted in significantly increased expressions of Bax/Bcl2 and cleaved Cas3/Cas3 and a lowered expression of c-Myc. CONCLUSIONS: Interference of FOXCUT can inhibit the proliferation and epithelial-mesenchymal transformation, enhance oxidative stress, induce mitochondrial function injury, and promote apoptosis in NPC cells, suggesting the potential of FOXCUT interference for targeted treatment of NPC.

Predictive Value of [18F]ML-10 PET/CT in Early Response Evaluation of Combination Radiotherapy with Cetuximab on Nasopharyngeal Carcinoma.

PURPOSE: Apoptosis may be an indication of success therapy, and precise detection of apoptosis can provide instructional suggestions in the therapy management of malignant tumors. PROCEDURES: We used CNE-1 cell lines for in vitro experiments, and colony formation assay, CCK-8 assay, cell apoptosis analysis, and western blotting were performed. For in vivo experiments, subcutaneous xenotransplanted tumor models of CNE-1 in nude mice were established. Then, small animal positron emission tomography/X-ray computed tomography (PET/CT) images were acquired by tail intravenous injection of 2-(5-[18F]fluoropentyl)-2-methyl-malonic acid ([18F]ML-10) or 2-deoxy-2-[18F]fluoro-D-glucose ([18F]FDG) before and 24 h and 48 h after treatment. Moreover, expression of epidermal growth factor receptor (EGFR), Ki-67, Glut-1, and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) was examined by immunohistochemical examination. Tumor volumes of mice were recorded every 2 days. RESULTS: In the presence of Cetuximab, the number of colonies of CNE-1 cells decreased significantly after irradiation at 1 and 2 Gy. In addition, Cetuximab increased the radiation-induced cytotoxicity and apoptosis of CNE-1 cells. Mechanistic studies demonstrated that Cetuximab enhanced radiosensitivity by suppressing the EGFR/PI3-K/AKT pathway. In PET/CT imaging, the tumors showed clear uptake of [18F]ML-10 at 24 h and 48 h after combined treatment, and the value of tumor/muscle (T/M) and SUVmax (the max of standard uptake value) was significantly higher than those of the other three groups. The T/M of [18F]ML-10 uptake showed a positive correlation of 0.926 with the apoptosis index (P < 0.001). However, the uptake of [18F]FDG in tumors exhibited no trend among the four groups. The T/M of [18F]FDG revealed a positive correlation of 0.926 with Glut-1 intensity (P < 0.001). CONCLUSIONS: Our work revealed that Cetuximab could increase the radiosensitivity of CNE-1 cells both in vitro and in vivo. Apoptosis imaging with [18F]ML-10 PET/CT is a promising modality for application in the response prediction of nasopharyngeal carcinoma.