The Role And Mechanism Of FBW7 Deficiency In Advanced Non-small Cell Lung Cancer With Docetaxel Resistance

BackgroundLung cancer is one of the most common malignant tumors of human.Its morbidity and mortality first in all malignancies,and the number of lung cancer patients in our country has increasing rapidly.NSCLC accounts for about 80%-85%of all lung cancer,and 65%-80%of NSCLC patients have been diagnosed at the advanced stage^[1],comprehensive treatment has become the primary treatment option for advanced lung cancer,and chemotherapy has been considered as an important part of this comprehensive treatment.Because of the existence of drug resistance,many patients have relapsed or progressed soon after chemotherapy,and the resistance always lead to unsuccessful effect.Finding biomarkers that can predict the efficacy of drug treatment and reversing the resistance of tumors to chemotherapeutic drugs have become the focus of NSCLC research.Docetaxel is an anti-microtubule chemotherapeutic agent that acts on cellular tubulin,which can prevent the normal physiological accumulation of intracellular microtubules and cause the tumor cells arrest at the G2/M phase,resulting in the withering of cells^[2].Like other chemotherapeutic drugs,the drug resistance of docetaxel reduces its efficacy.However,no indicators are available for determining drug resistance of docetaxel in NSCLC patients in clinical.Terefore,study the resistance mechanism and discover new indicators to evaluate tumor resistance are important to personalized treatment,furthermore,improve the efficacy of chemotherapy in clinical.MethodRT-PCR and Western-blot were used to detect the differences of FBW7 expression in docetaxel-resistant cell line SPC-A1/DTX and parental SPC-A1 cells,and the overexpression and interference sequences of FBW7 were constructed.The SPC-A1/DTX and parental SPC-A1 cells were transfected with lentiviral packaging,and the SPC-A1/DTX FBW7 O/E cell line and SPC-A1 FBW7 D/R cell line were screened by monoclonal screening method.RT-PCR and Western-blot were also used to detect the differences of FBW7 expression among SPC-A1/DTX,SPC-A1/DTX FBW7 O/E,SPC-A1 and SPC-A1FBW7 D/R cell lines.Finally,MTT colorimetric assay and colony formation assay were used to research the effects of regulation of FBW7 on the sensitivity to docetaxel.ResultsRT-PCR and Western-blot proved that the expression of FBW7 in NSCLC docetaxel-resistant cell line SPC-A1/DTX was significantly lower than that of parental cell line SPC-A1.With lentiviral transfection and monoclonal screening,a SPC-A1 FBW7 D/R cell line with down-regulated FBW7 expression and an SPC-A1/DTX FBW7 O/E cell line with up-regulated FBW7 expression were constructed.The expression of FBW7 in SPC-A1cell line and SPC-A1/DTX FBW7 O/E cell line was higher than that of SPC-A1/DTX FBW7 O/E cell line and SPC-A1 by RT-PCR and Western-blot./DTX cell line.Finally,MTT colorimetric assay and colony formation assay showed that SPC-A1 cell line and SPC-A1/DTX FBW7 O/E cell line were more sensitive to docetaxel than SPC-A1 FBW7D/R cell line and SPC-A1/DTX cell line.ConclusionFor non-small cell lung cancer,the sensitivity to docetaxel was higher in cells with high expression of FBW7 than the cells with low expression of FBW7;the loss of FBW7 gene was associated with drug resistance of NSCLC to docetaxel.However,the specific mechanism of FBW7 deletion causing non-small cell lung cancer resistance to docetaxel still needs further study.