| OBJECTIVE:The aim of this study was to explore the roles of micro RNA-23 a in determining sensitivity of locally advanced non-small cell lung cancer(NSCLCL) to concurrent chemoradiotherapy, to define the underlying molecular mechanism and to discuss the potential of miR-23 a as a biomarker for predicting radio-sensitivity.METHODS:1. The expression level of micro RNA-23 a in serum from 76 patients with a histological diagnosis of LA-NSCLC and 35 healthy people was measured by RT-PCR. The eligible patients never received any treatment before concurrent chemoradiotherapy.2. We use RT-PCR to analyze the difference expression of micro RNA-23 a in A549 and radioresistance-A549(R-A549) cells.3. The transfection of A549 with mimic and transfection of R-A549 cells with inhibitor of miR-23 a were performed to evaluate the role of miR-23 a in radio-sensitivity.4. The effect of miR-23 a on radio-sensitivity of the R-A549 and A549 cells was detected by MTT assay and flow cytometry analysis of apoptosis.RESULTS:1?Total of 76 LA-NSCLC patients were enrolled in the current study, including 45 male and 31 female, with the median age 58 years. The tumor stage of 30 patients was IIIA and 46 patients were IIIB. All of these specimens were treated with concurrent chemoradiotherapy.Moreover, 35 healthy people were enrolled as the control group in the study, which was constituted of 21 man and 14 women, with the median age 53 years. No significant differences were observed in age, sex and KPS between the NSCLC patients and the control group.2. All of the enrolled LA-NSCLC patients completed the concurrent chemoradiation. The RECIST was used to evaluate objective tumor response. Of the 76 patients, 6 cases was observed complete remission(CR), 49 cases PR, 18 cases SD and PD in 3 patients. Wedefined the CR and PR patients as “radiosensitive” group, SD and PD patients as“radioresistant” group. The calculated of 2- ? ?Ctwas used to evaluate the expression of miR-23 a. Results: 1)The serum miR-23 a level in NSCLC patients was 4.19 times as many as that in the control group. The expression of miR-23 a may serve as a biomarker for the diagnosis of NSCLC cancer. 2) Higher expression of miR-23a(2.97 times) was observed in NSCLC patients that were resistant to chemoradiation therapy, as compared with the radiosensitive set. The expression of miR-23 a may be used to measure the sensitivity of NSCLC patients to radiation therapy.3. The calculated of 2-??Ctwas used to evaluate the expression of miR-23 a in A549 and R-A549 cells. The relative miR-23 a serum level in R-A549 cells 3.43 times as many as that in the A549 cells.4. R-A549 cell lines transfected with miR-23a-inhibitor showed a significant increase of apoptosis compared with those cells with the miR-23a-inhibitor control. A549 cell lines transfected transfected with miR-23 a mimic showed a significant increase of metabolically active cells compared with the miR-23a-mimic negative control. These results suggested that the expression of serum miR-23 a can accurately reflect the differences of the apoptosis and the proliferation of A549 and R-A549 cell lines and affect the sensitivity of cells of solid tumor to radiation therapy CONCLUSIONS:The expression level in serum of micro RNA-23 a of LA-NSCLC patients before treatment may serve as a biomarker for the diagnosis of NSCLC cancer and can be used to measure the sensitivity of NSCLC patients to radiation therapy. Higher expression level of miR-23 a was observed in LA-NSCLC patients and R-A549 cell lines that were resistant to radiation therapy, when compared with the sensitive patients and the cells. Transfected with miR-23a-inhibitor in R-A549 cells increased cell apoptosis and the cells sensitivity to radiotherapy. The significant inverse correlation between the expression of miR-23 a and APAF1 mRNA in A549 cell lines was found. |
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