| Objiective:To investigate the biological traits of CNE-2-Rs, a type of radioresistant nasopharyngeal carcinoma (NPC) cells derived from the CNE-2, such as radioresistance, paclitaxel sensitivity, invasion and metastasis ability. Beyond our previous research, to explore wether epithelial-mesenchymal transition (EMT) is involved in giving birth to such traits of the CNE-2-Rs.Methods:To determine the biological traits of the CNE-2-Rs. CCK-8assay, clone formation assay and flow cytometry were used to determine radioresistant traits of the CNE-2-Rs and the CNE-2. CCK-8assay was utilized to investigate the paclitaxel sensitivity of the CNE-2-Rs and the CNE-2. Wound healing assay and transwell chamber invasion assay were carried out to observe the migration and invasion ability of the CNE-2-Rs and the CNE-2.To observe the EMT-related morphology and molecules of the CNE-2-Rs. A microscope and the western blot assay were used to observe the morphology and EMT-related molecule expression level of the CNE-2-Rs and the CNE-2respectively. The western blot assay was utilized to determine the EMT-related molecule expression in NPC tissue specimens.Results:After given different doses (4Gy,6Gy,8Gy) of radiation, The CNE-2-Rs had higher survival rate in4th day compared with the CNE-2. The CNE-2-Rs exhibited a higher survival rate than the CNE-2in the subsequent5days after given4Gy radiation, and the gap between the two was time-dependent. The CNE-2-Rs could form larger and more clones compared with the CNE-2. Flow cytometry assay showed that,72h after given4Gy radiation, the apoptosis rate of the CNE-2-Rs was lower than that of the CNE-2(22.43+0.18%vs38.07+0.66%, P<0.001). There was no significant difference of cell cycle distribution between the two in the absence of radiation. However,72h after radiation, The CNE-2-Rs, compared with the CNE-2, increased the cell proportion in S stage (28.78±1.72vs21.42±1.09, P<0.05) and G2stage (37.34±3.68vs24.66±1.68, P<0.05), while decreased in G1stage (33.88±5.38vs53.91±1.6, P<0.05). All these data revealed that the CNE-2-Rs possess an increased radioresistance trait.The paclitaxel IC50of the CNE-2-Rs was much higher than that of the CNE-2(8.53±3.61×10-1vs6.28±2.37×10-2(nM), P<0.001). The paclitaxel resistance index of the CNE-2-Rs was13.57±1.58. All the data indicated that the CNE-2-Rs gain a more paclitaxel-resistant trait.After72hours, the wound nearly healed in the CNE-2-Rs group, exhibiting a increased migration ability. Moreover, the cells migrating to the bottom chamber were much more in the CNE-2-Rs group than in the CNE-2group ((86±6) vs (26±8),P<0.01). These data demonstrated that the CNE-2-Rs significantly elevate its migration and invasion ability.After long-term radiation, the CNE-2transformed its morphology. CNE-2-Rs gained a fibrocyte-like morphology, appearing a long shape and loose cell contact. Compared with the CNE-2,The CNE-2-Rs decreased its expression of E-cadherin, while increased Vimentin. In residual NPC tissue specimens after radiotherapy, the expression level of E-cadherin was higher, while the expression level of Vimentin was lower than that of the coupled tissue specimens.Conclusion:The radioresistant CNE-2-Rs cells possess an increased radioresistance, paclitaxel-resistance, migration and invasion ability. The CNE-2-Rs cells gain a typical transformation in ENT-related morphology and molecules. These results suggest that EMT may have a close relation with the malignant progression of the NPC cells, laying a firm foundation for, from the same perspective, further investigating the malignant biological traits of NPC in the future. |
PDF Full Text Request