ABSTRACT
@#[Abstract] Objective: To establish paclitaxel(PTX)-resistant human triple negative breast cancer cell line and to examine the expression profile of FA-related genes and FANCF, the correlation between the expression of FA-related genes, FANCF and PTX-resistance in breast cancer were further analyzed. Methods: PTX-resistant MDA-MB-231 cell line was established by means of long-term PTX-exposed culture. The sensitivity of the cells to paclitaxel was determined by the CCK8 assay. The cell cycle distribution was examined by flow cytometry after exposure to the paclitaxel. The expression of FA-related gene mRNA and FANCF protein were examined by using real time quantitative PCR and Western blotting. The expression of FANCF in the cells was reduced by RNAi interference technology and the effect of the RNAi was verified. Results: MDA-MB-231/PTX cell showed a 9.9-fold resistance to paclitaxel, indicating that the cell had acquired resistance to PTX. PTX treatment significantly induced G0/G1 arrest and the number of cells in phase S markedly decreased after exposure to PTX. The mRNA and protein expression of FANCF was significantly higher in PTX-resistant cell than that in PTX-sensitve parental cell，Knockdown of FANCF induced apoptosis in MDA-MB-231/PTX cell as well as in parental cell. FANCF knockdown increased the sensitivity of paclitaxel to both MDA-MB-231 and MDA-MB-231/PTX cells (P<0.05 or P<0.01). Conclusion: FANCF played an important role in PTX resistance of the breast cancer cells and FANCF might be a target for therapy aimed at reversing chemoresistance.
ABSTRACT
@# Objective: To investigate the expression profile and function of FANCF gene (a key gene in FA/BRCA pathway) in both cisplatin (DDP)-resistant and DDP-sensitive human triple-negative breast cancer cell lines and to analyze its correlation with DDP-resistance in breast cancer. Methods: The DDP-resistant breast cancer MDA-MB-231 cell line (MDA-MB-231/DDP) was established by induction of gradient DDP. The expression of FANCF gene in both sensitive and resistant cell lines was knocked-down by RNAi interference technology and the knockdown efficiency was validated at both RNA and protein level. The cell viability of MDA-MB-231 cells and MDA-MB-231/DDP cells was determined by the CCK8 assay; Flow cytometry was used to examine the cell cycle distribution and apoptosis; the mRNAand protein expressions of FANCF gene were examined by using qRT-PCR and western blotting, respectively. Results: The resistance index of MDA-MB-231/DDP cells was 13.5 after 3-month induction. The mRNA and protein expressions of FANCF were significantly increased in MDA-MB-231/DDP cells (all P<0.01). Cell cycle analysis indicated that the DDP treatment significantly induced G0/G1 arrest and decreased the cell proportion in phase S and G2/M. siRNA-mediated knockdown of FANCF could not only be able to increase sensitivity of MDA-MB-231 to DDP but also promote the cell apoptosis (all P<0.01). Conclusion: FANCF attributes to the occurrence of DDP-resistance through anti-apoptosis effect, which might be served as a potential treatment target for drug-resistant human breast cancer.