| Objective: Through the detection of small cell lung cancer(small cell lung cancer,SCLC)first diagnosis and chemotherapy in patients with [adopt EC(Etoposide,Etoposide,EPEG + Carboplatin,Carboplatin,CBP)chemotherapy regimens] after different periods of miR-181-b content in the peripheral blood and regulating its expression level in SCLC cell lines to explore its resistance mechanism of SCLC,etc,provide the basis for looking for SCLC new therapeutic targets.Methods:1.General data of 30 cases of SCLC patients and 30 healthy subjects(control group)confirmed by pathology in the department of thoracic surgery and oncology of our hospital from December 2016 to May 2017 were collected.2.Peripheral blood samples of the healthy control group and before and after chemotherapy were collected to detect the expression level of mir-181 b.Statistical analysis was performed to determine the relationship between the content changes and SCLC resistance.3.The expression level of mir-181 b in clinical SCLC cell lines(H446 cell lines and H446 drug-resistant cell lines)was detected in the laboratory.Then,mir-181 b contents of H446 cell lines and H446 drug-resistant cell lines were overexpressed through the construction of lentivirus vectors,and the drug sensitivity of cell lines before and after overexpression was detected by CCK8 method,so as to determine the correlationbetween the content changes and drug resistance.Results:1.MiR-181-b in healthy people and patients with SCLC already after chemotherapy the expression level of contrast between groups of miR-181-b content in blood samples,miR-181-b in the peripheral bloodof patients with untreated SCLC in significantly lower compared with normal control group,with significant statistical difference(P<0.01),but after EC after solution treatment,its expression level was increased,butstill below normal levels(P<0.01).2.The expression level of mir-181 b in SCLC patients with different chemotherapy cycles after 1 cycle of chemotherapy,the expression level of mir-181 b increased,but was lower than the normal level(P<0.01).After 6 times of chemotherapy,the contents in each group were significantly increased and decreased,with peaks in 3 and 4.There were significant differences between the two groups before and after chemotherapy,and the contents were increased(P<0.01).There was a statistical difference between groups 1 and 4(P<0.01),indicating that the content increased with the progress of chemotherapy,but decreased after the fifth group.There was a significant statistical difference between groups 5,6,3and 4(P<0.01)(as shown in Fig1B).With the increase of chemotherapycycle,the decrease of its content may indicate the generation of drugresistance of SCLC.3.The expression level of mir-181 b in SCLC(H446 cell line and H446 drug-resistant cell line)was detected by real-time quantitative qPCR,and the expression level of mir-181 b in H446 cell line was lower than that in the control group(P<0.01),while the content of mir-181 b in H446 cell line was higher than that in H446 drug-resistant cell line(P<0.01).4.Changes in sensitivity of sensitive and drug-resistant lung cancer cell lines to chemotherapy drugs after mir-181 b transfection H446 cell line showed no statistically significant difference between the two groups(P=0.3741>0.05)before and after mir-181 b overexpression by LNV transfection.05);There was a statistically significant difference before and after overexpression of mir-181 b in the drug-resistant group(P=0.01047 < 0.05);In addition,there was a statistically significant difference between the drug-resistant group and the sensitive group before and after overexpression of mir-181b(P=0.00912 < 0.01 VS P=0.0127 < 0.05).After overexpression of mir-181 b by lentivirus transfection in drug-resistant H446 cell lines,the IC50 value of chemotherapy drugs decreased significantly(412.28 + 12.71 vs269.55 + 10.21).Conclusion:1.Mir-181 b is low-expressed in SCLC patients,and first-line chemotherapy of SCLC can promote its recovery,but cannot restore to the normal level,and its expression level decreases again after the occurrence of drug resistance,indicating that mir-181 b has a certain impact on the sensitivity of SCLC to chemotherapy;2.Mir-181 b has a low expression abundance in H446 cell lines and a lower content in drug-resistant strains.By overexpressing mir-181 b in drug-resistant strains,it can be clear that it has a certain impact on the recovery of drug sensitivity of SCLC drug-resistant cell lines,which is expected to be an indicator to evaluate the effect of SCLC chemotherapy. |
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