OBJECTIVE: To further determine the role of FOLR1 in taxol resistance of nasopharyngeal carcinoma (NPC) and whether inhibition of FOLR1 expression reverses the taxol-resistant phenotype. STUDY DESIGN: Correlation study between gene expression and cancer cell survival. SETTING: University hospital. SUBJECTS AND METHODS: Three taxol-resistant sub-cell lines with a different resistant index were established from the parental CNE-1 NPC cell line. The correlation between FOLR1 expression and taxol sensitivity was statistically analyzed. Inhibition of FOLR1 expression was carried out by RNA interference and by a FOLR1-specific monoclonal antibody, and taxol sensitivity was examined by colony formation assays. FOLR1 expression was also examined in 72 NPC patient specimens by immunohistochemistry. RESULTS: The levels of FOLR1 expression were positively and significantly correlated with a taxol resistance phenotype (P < .05). Inhibition of FOLR1 expression resulted in a significantly increased sensitivity of taxol to taxol-resistant NPC cells (P < .05). An increase of FOLR1 expression by gene transfection caused a taxol-resistant phenotype in parental NPC cells. The level of FOLR1 expression was found to be related to clinical stage in NPC tissue samples. CONCLUSION: These results suggest that FOLR1 plays an important role in taxol resistance of NPC cells.
OBJECTIVE: To further determine the role of FOLR1 in taxol resistance of nasopharyngeal carcinoma (NPC) and whether inhibition of FOLR1 expression reverses the taxol-resistant phenotype. STUDY DESIGN: Correlation study between gene expression and cancer cell survival. SETTING: University hospital. SUBJECTS AND METHODS: Three taxol-resistant sub-cell lines with a different resistant index were established from the parental CNE-1 NPC cell line. The correlation between FOLR1 expression and taxol sensitivity was statistically analyzed. Inhibition of FOLR1 expression was carried out by RNA interference and by a FOLR1-specific monoclonal antibody, and taxol sensitivity was examined by colony formation assays. FOLR1 expression was also examined in 72 NPC patient specimens by immunohistochemistry. RESULTS: The levels of FOLR1 expression were positively and significantly correlated with a taxol resistance phenotype (P < .05). Inhibition of FOLR1 expression resulted in a significantly increased sensitivity of taxol to taxol-resistant NPC cells (P < .05). An increase of FOLR1 expression by gene transfection caused a taxol-resistant phenotype in parental NPC cells. The level of FOLR1 expression was found to be related to clinical stage in NPC tissue samples. CONCLUSION: These results suggest that FOLR1 plays an important role in taxol resistance of NPC cells.
Authors: Daniel J O'Shannessy; Gordon Yu; Robert Smale; Yao-Shi Fu; Sunil Singhal; Robert P Thiel; Elizabeth B Somers; Anil Vachani Journal: Oncotarget Date: 2012-04