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Hua-ming Chi, Jing-dong Du, Jie Cheng, Hua-dong Mao
(Department of Otolaryngology, Renhe Hospital of China Three Gorges University, Yichang, Hubei, China (mainland))
Med Sci Monit 2019; 25:475-483
Oxaliplatin (L-OHP) is an important chemotherapy regimen for nasopharyngeal carcinoma (NPC), but can fail due to drug resistance. In this study, the role of Txr1 (taxol-resistant gene 1) in oxaliplatin resistance was investigated.
MATERIAL AND METHODS: Cell viability assay was carried out using the CellTiter-Glo Luminescent Cell Viability Assay Kit. CNE1 and CNE2 cells were cultured continuously with gradually increasing concentrations of L-OHP for 6 months to establish drug-resistant cell lines. Autophagy was detected by electron microscopy. Txr1 expression in NPC cells was detected via Western blotting and real-time quantitative PCR (qRT-PCR).
RESULTS: In L-OHP-resistant CNE1/L-OHP and CNE2/L-OHP cells, mRNA and protein expression of Txr1 increased compared to the parental cells, and downregulation of Txr1 re-sensitized drug-resistant cells to L-OHP. Moreover, we found that Txr1-mediated L-OHP resistance was associated with increased autophagy. Txr1-overexpression cells developed L-OHP resistance and a high level of autophagy. Inhibiting autophagy using 2 different methods – inhibition of autophagy-related gene expression and autophagy inhibitor – attenuated L-OHP resistance of NPC cells.
CONCLUSIONS: We conclude that the detection of Txr1 might become a good indicator to evaluate the treatment and prognosis of nasopharyngeal carcinoma. Our data suggest that further investigation of Txr1 in the setting of L-OHP resistance is warranted.