| ObjectiveIn our previous work,we screened the differential expression levels of mi RNAs in A549 cells before and after 2 and 4 Gy X-ray irradiation respectively through the mi RNA expression chip,and found that the expression level of mi R-21 significantly changed.The primary purpose of this study is to further investigate the possible conection of mi R-21 expression and the survival and prognosis in clinical lung tissues and serum sample from lung cancer patients,and to explore the effect and significance of ionizing radiation on mi R-21 in lung cancer patients and A549 cells in vitro and in vivo.MethodsPostoperative pathological data and clinical data of 20 lung cancer patients were collected,including 10 cases of squamous cell carcinoma(SCC)and 10 cases of adenocarcinoma(ADC),in adjacent normal lung tissues served as controls.The serum samples and clinical data of 103 patients with lung cancer were collected,including a total of 87 cases of non-small cell lung cancer(NSCLC)and 16 cases of small cell lung cancer(SCLC),NSCLC contained 62 cases of adenocarcinoma and 25 cases of squamous cell carcinoma.The serum of 30 healthy checkup from hospital physical examination center was collected to be used as normal controls.Real-time quantitative PCR assay was used to detect the expression of mi R-21 in clinical lung tissues and serum sample of lung cancer patients,whom survival rate was analyzed.The A549 cells cultured in vitro were irradiated with 2 and 4 Gy doses of X-ray respectively,and the A549 cells at different time points after irradiation were used to detect the expression level of mi R-21 in A549 cells by real-time fluorescence PCR,and 0 Gy non irradiated A549 cells were used as negative control group.The A549 cells irradiated by 0,2,and 4 Gy doses of X-ray were injected into nude mice through the rat tail vein to make the animal model of lung metastatic carcinoma in nude mice.0,2,4 Gy dose of X irradiated A549 cells were injected into nude mice by the tail vein,which served as animal models of cancer metastasis,real-time quantitative PCR assay was performed to detect the expression of mi R-21 in clinical lung tissues and serum samples from nude mice,and the nude mice in the blank control group were not injected with A549 cells.The expression level of each group of mi R-21 was 1.8 times higher than that of the control group was defined as positive.This study uses SPSS 23.0 software to make statistical analysis,and P<0.05 was interpreted as possess difference of statistical significance.ResultsIn 20 cases of lung cancer,the expression of mi R-21 was 60%(12/20)in pathological tissue.There was no significant difference in the detection rate between adenocarcinoma(5/10)and squamous cell carcinoma(5/10)(P > 0.05).The high expression of mi R-21 in the serum of 103 patients with lung cancer was 50.5%(52/103),and the difference between the detection rate of adenocarcinoma and squamous cell carcinoma was statistically significant(?2=5.766,P=0.016).In 103 patients with lung cancer,the positive rate of serum mi R-21 in radiotherapy group was 63.1%(29/46),which was significantly higher than that in the non radiotherapy group(40.4%,23/57)(?2=5.244,P=0.022).In 87 patients with non-small cell lung cancer,the positive rate of serum mi R-21 was 66.7%(26/39)in the radiotherapy group,which was significantly higher than that in the non radiotherapy group(39.6%,19/48)(?2=6.321,P=0.012).The survival analysis of Kaplan-Meier showed that the prognosis of patients with high expression of mi R-21 was significantly lower than those of low expression,and the difference was of statistically significant(P=0.005).Multivariate analysis of Cox regression showed that mi R-21 overexpression(P=0.001)and regional lymphnode metastasis(P=0.037)and radiotherapy(P=0.041)were independent risk factors for prognosis in patients with non-small cell lung cancer.The expression of mi R-21 increased significantly at different time points after 2 and 4 Gy doses of X-rays irradiated with A549 cells(t=-7.552~-1.206,P<0.05).After injecting A549 cells irradiated by 0,2 and 4 Gy doses of X-ray into the nude mice,the expression level of mi R-21 in nude mice serum and lung tissue increased significantly(t=-47.845~-2.356,P<0.05).ConclusionIn pathological specimens of patients with lung cancer after operation,the detection rate of mi R-21 is higher than that of squamous adenocarcinoma in all lung cancer patients serum samples,the detection rate of serum mi R-21 was significantly higher than that of squamous cell carcinoma,adenocarcinoma and small cell lung cancer,suggesting that mi R-21 expression may be associated with the pathological type of lung cancer itself,it has a tendency to become a new potential biomarkers of pathological diagnosis of lung cancer.In all the patients with lung cancer and non-small cell lung cancer patients in two groups,the detection rate of serum mi R-21 radiotherapy group were significantly higher than those without radiotherapy group of patients,the results indicate that ionizing radiation(radiotherapy)may increase the expression of mi R-21 and Kaplan-Meier survival analysis and Cox regression model analysis showed that mi R-21 may be a new target treatment of patients with non-small cell lung cancer and new index for determine prognosis.In vitro X ray irradiation of A549 cells at different time points,the expression level of mi R-21 was increased,indicating the 2 and 4 Gy X-ray irradiation can increase the expression of mi R-21 in A549 cells.In the model of pulmonary metastasis in nude mice,the serum and lung tissue of nude mice with mi R-21 expression level were significantly higher than the control group,which further indicated 2 and 4 Gy X-ray irradiation of A549 cells also increased the expression levels of mi R-21 in the lung tissues and serum.The results suggest that mi R-21 may be involved in the regulation of change with the biological activity of A549 cells induced by radiation,and also promoted the invasion and metastasis in vivo. |
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