| Background and Objective Lung cancer is one of the leading malignancies worldwide. Most patients with lung cancer are diagnosed in advanced stage. Chemotherapy remains an important modality of treatment. Multidrug resistance(MDR) of tumor cells is the main reason for the failure of chemotherapy. Current studies show that the molecular mechanism of MDR is extremely complicated. Many researches focus on topics such as drug efflux pump mediated by membrane transporters, detoxification enhancement of tumor cells mediated by enzyme, the change of target enzymes of drugs or the change of affinity of enzymes and drug in tumor cells, and the increase of anti-apoptotic effect of tumor cells. Among them, ATP-binding cassette(ABC) family plays the most important role in tumor MDR as membrane transporters. ATP-binding cassette, sub-family C, member 4(ABCC4) is a member of the sub-family C of ABC transporters family. ABCC4 has been identified as an ATP-dependent efflux pump which is involved in the MDR of tumor cells by conjugating and pumping chemotherapy drugs out of the cells. It has been reported that ABCC4 was closely related to drug resistance of gastric cancer, prostate cancer, pancreatic cancer and ovarian cancer. Based on our previous study and related articles, ABCC4 was highly expressed in lung cancer cell lines, and was higher in drug-resistant lung cancer cells than in parental cells. This study was designed to investigate the effect and mechanism of ABCC4 on drug resistance in human lung cancer cells, and expected to find out a new target for the research of drug resistance to chemotherapy in lung cancer.Methods Human lung cancer cell lines, A549 and 801 D were infected with ABCC4 short hairpin RNA(sh RNA) recombinant lentivirus to establish A549 ABCC4-knockdown(KD) cell line and 801 D ABCC4-KD cell line. Western blot was used to detect the expression level of ABCC4 protein. The inhibition rate of cell proliferation of both cell lines were detected by MTS after cultured with different concentrations of epirubicin(EPI) for 24 h, and the half inhibitory concentration(IC50) were calculted. MK-571, an ABCC inhibitor, was used to inhibit the expression of ABCC4 in A549 cell line. The change of inhibition rate of cell proliferation was also detected by MTS after cultured with MK-571 and different concentrations of EPI for 24 h, and the change of the IC50 values were observed.Results(1) ABCC4 sh RNA recombinant lentivirus was infected into A549 and 801 D cells to obtain A549-ABCC4-KD and 801D-ABCC4-KD cells. Nonsilencing sh RNA recombinant lentivirus was infected into A549 and 801 D cells as a negative control(A549-NC and 801D-NC). The expression of ABBC4 was markedly downregulated in A549 ABCC4 KD cells and 801 D ABCC4 KD cells, which meant that the ABCC4 genes knockdown cell lines were built successfully.(2) Compared with A549-NC cells, the inhibition effect of EPI at the concentration of 50μg/ml, 60μg/ml, and 70μg/ml on cell proliferation of A549-ABCC4-KD was significantly enhanced, and the IC50 value was significantly decreased. The inhibition effect of EPI at the concentration of 0.5μg/ml, 1μg/ml, 2μg/ml and 4μg/ml on cell proliferation of 801D-ABCC4-KD and 801D-NC were not statistically different, and the IC50 value has no significant difference between two cell lines.(3) Compared with A549 cells cultured without MK-571, the inhibition effect ofEPI at the concentration of 30μg/ml, 40μg/ml, 50μg/ml, 60μg/ml, and 70μg/ml on cell proliferation of A549 cell in the presence of MK-571 was significantly enhanced, and the IC50 value was significantly decreased.Conclusion(1) ABCC4 was the target of chemotherapy drug resistance of lung cancer. MK-571, an ABCC4 inhibitor, inhibited the expression of ABCC4, improved the chemotherapy curative effect, and further proved the vorth of ABCC4 as a chemotherapy drug resistance targets.(2) After downregulating the expression of ABCC4, 801 D cells reacted differently to chemotherapy compared with A549 cells. The mechanism in drug resistance in lung cancer could be more complicated, and mechanism in drug resistance independent on ABCC4 may exist.Background and Objective ATP-binding cassette, sub-family C, member 4(ABCC4) is a member of the C sub-family of ABC transporters family. Through conjugating and pumping chemotherapy drugs out of the cells, ABCC4 is involved in MDR of tumor cells. The results had showed that the expression of ABCC4 was associated with drug resistance of A549 cells to EPI. And ABCC4 m RNA levels of 30 patients both in lung cancer tissue and matched adjacent tissue were detected, indicating ABCC4 m RNA levels in cancer tissue were much higher. The related reports for discussing the serum ABCC4 levels in lung cancer patients and its clinical significance had not been released. This study was designed to detect the serum ABCC4 levels in lung cancer patients and analyze its clinical significance. Similarly, the research was to monitor the variation of serum ABCC4 levels during chemotherapy and discuss the relationship between the variations in serum ABCC4 levels and the chemotherapy curative effect for further correlation of variation in serum ABCC4 levels and resistance.Methods A total number of 117 patients with lung cancer registered at Beijing Chest Hospital, Capital Medical University, China, from August 2013 to June 2014 were involved in this study. All patients were newly diagnosed including 35 cases underwent surgery and 82 cases underwent platinum-based doublet chemotherapy. Serum ABCC4 levels before treatment(both surgery and chemotherapy) in all patients were detected using enzyme-linked immunosorbent assay(ELISA). Fifty-three healthy volunteers were recruited as controls. The patients who underwentchemotherapy got efficacy evaluation after 3 weeks from the beginning of the first, second and fourth cycle of chemotherapy. Tumor responses were categorized as disease control(complete response/partial response/stable disease, CR/PR/SD) and progressive disease(PD). Sequential measurement of serum ABCC4 levels in lung cancer patients was conducted in parallel with response evaluation. We explored the relationship between serum ABCC4 levels and clinical parameters, meanwhile the correlation of variation in serum ABCC4 levels and chemotherapy curative effect in lung cancer patients.Results(1) Compared with that in the healthy controls, the serum ABCC4 level markedly increased in lung cancer patients(P < 0.001). The positive rate of serum ABCC4 in lung cancer patients was significantly higher than that of healthy controls(P < 0.001).(2) Both the levels and the positive rate of serum ABCC4 in lung cancer patients were correlated with distant metastasis and TNM stage(P < 0.05). The levels and the positive rate of serum ABCC4 raised greatly in patients with early stage.(3) Both the levels and the positive rate of serum ABCC4 in patients with NSCLC were correlated with regional lymph node metastasis, distant metastasis and TNM stage(P < 0.05). The levels and the positive rate of serum ABCC4 raised greatly in patients with early stage.(4) Serum ABCC4 levels in patients with NSCLC and SCLC were stable following chemotherapy. There was no association between the variation of serum ABCC4 levels and chemotherapy curative effect.Conclusion(1) The serum level of ABCC4 in the early diagnosis of lung cancer maintains potential clinical application prospects.(2) The serum level of ABCC4 in lung cancer is associated with gender and histological types. The serum level of ABCC4 in lung cancer patients with early stage was significantly higher than those with advanced stage.(3) There was no correlation between the variation of serum level of ABCC4 and chemotherapy curative effect.Background and Objective Chemotherapy is the main treatment for advanced stage lung cancer. It is very important to monitor the efficacy. Response Evaluation Criteria in Solid Tumors(RECIST) based on imaging examination is the gold standard for assessing efficacy at present. But radiological changes appeared relatively late and may delay the assessment of chemotherapy curative effect. Compared to radiological changes, the variation of serological markers appeared earlier. Serological markers are simple, noninvasive, economical and repeatable reliably; meanwhile they are easy to be collected. So serological markers may monitor the changes of biological characteristics of tumor in treatment and is helpful for effect assessment. The invasion and metastasis of neoplasm are the main cause of cancer deaths. Matrix metalloproteinases(MMPs) family is one of hot spots of invasion and metastasis in lung cancer. Matrix metalloproteinase 9(MMP-9), known as a member of the MMPs family, is involved in the degradation of the main constituents of basement membrane and the extracellular matrix(ECM), which is closely correlated with tumor cells invasion and metastasis. Scholars have already studied the relationship between variation in serum MMP-9 levels and chemotherapy curative effect. The results demonstrated that serum MMP-9 levels in responders decreased significantly after chemotherapy compared with stabilized non-responders. These findings suggested that further studied variation in serum MMP-9 levels is important reference to assess chemotherapy curative effect of the lung cancer. In this study, we conducted sequential measurement of serum MMP-9 levels during chemotherapy andinvestigated the correlation of variation in serum MMP-9 levels with chemotherapy curative effect in patients with lung cancer. We also evaluated the potential significance of variation in serum MMP-9 levels to assess chemotherapy curative effect.Methods Eighty-two patients with advanced lung cancer registered at Beijing Chest Hospital, Capital Medical University, China, from August 2013 to June 2014 were involved in this study. All patients were newly diagnosed and were treated with standard platinum-based chemotherapy. Serum MMP-9 levels was measured by enzyme-linked immunosorbent assay before chemotherapy and 3 weeks after the beginning of the first, second and fourth cycle of chemotherapy. Patient responses were evaluated 3 weeks after the beginning of the first, second and fourth cycle of chemotherapy according to Response Evaluation Criteria in Solid Tumors(RECIST) 1.1. Tumor responses were categorized as disease control(complete response/partial response/stable disease, CR/PR/SD) and progressive disease(PD). Subsequent analyses were designed to investigate the association between the variation in serum MMP-9 levels during chemotherapy and chemotherapy curative effect in patients with lung cancer.Results Our results showed serum MMP-9 levels decreased after chemotherapy in NSCLC patients. According to the response evaluation, we analyzed the difference of the variation of the serum levels of MMP-9 in patients with different chemotherapy curative effect evaluated after one cycle, two cycles and four cycles of chemotherapy. We analyzed the difference of the variation of serum MMP-9 levels between the PD patients and the CR/PR/SD patients. The variation of serum MMP-9 levels in the PD patients was the changes between the PD and before PD. The variation of serumMMP-9 levels in CR/PR/SD patients was the changes between the CR/PR/SD and the previous time point of collecting specimens. Compared with the serum level of MMP-9 before PD, patients obtained PD owned elevated serum levels of MMP-9. Compared with the previous time point of collecting specimens, the serum levels of MMP-9 in the CR/PR/SD patients went down or maintained stable. The difference of variation of serum MMP-9 levels in patients with different chemotherapy curative effect were all statistically significant after one cycle,two cycles and four cycles(after one cycle: P < 0.001;after two cycles: P < 0.001;after four cycles: P = 0.01). We further analyzed the correlation between variation in serum MMP-9 levels and chemotherapy curative effect. The elevated rate of serum MMP-9 levels in patients with PD evaluated after one cycle, two cycles and four cycles were 100%, 76.9% and 84%, respectively. The chemotherapy curative effect evaluated after one cycle and two cycles were correlated with the variation of serum MMP-9 levels(after one cycle: P = 0.002;after two cycles: P =0.002).Conclusion(1) There was no correlation between the serum level of MMP-9 in lung cancer patients and gender, age, smoking status, PS score, histological types, primary tumor size, regional lymph node metastases, distant metastases and TNM stages.(2) The variation of serum MMP-9 levels in patients with NSCLC during chemotherapy was closely related to chemotherapy curative effect and could be useful to monitor chemotherapy curative effect.Background and Objective Epidermal growth factor receptor(EGFR) tyrosine kinase inhibitor(TKI) treat advanced non-small cell lung cancer with EGFR-mutation effectively. However, most patients obtained EGFR-TKI resistance without effective therapy plans. We evaluated different treatment strategies after EGFR-TKI resistance for the curative effects and survival.Methods We retrospectively analyzed 240 patients with advanced lung adenocarcinoma with EGFR-TKI resistance and following subsequent treatment. According to the first strategies after EGFR-TKI failure, patients were divided into the EGFR-TKI continuation(21 cases), EGFR-TKI continuation with chemotherapy(23 cases), chemotherapy alone(143 cases) and best supportive care(BSC)(53 cases). We evaluated different treatment strategies for the curative effects and survival.Results All the 240 patients were evaluable for overall survival(OS). Except for 53 cases of BSC, the remaining 187 patients were able to be assessed the curative effects and progression-free survival(PFS) after treatments of EGFR-TKI failure. The disease control rates(DCR) of the patients in EGFR-TKI continuation, EGFR-TKI continuation with chemotherapy, and chemotherapy alone groups were 66.7%, 73.9%, and 44.8% respectively. The results showed that the DCR for the EGFR-TKI continuation with chemotherapy group was significantly higher than the chemotherapy alone group(OR = 4.057,95%CI = 1.485-11.083,P = 0.006). The median post-progression PFS for the three groups were 3.0, 3.3, and 2.0 months respectively. The post-progression PFS of EGFR-TKI continuation withchemotherapy group was significantly longer than the chemotherapy alone group(HR = 0.611,95%CI = 0.385-0.971,P = 0.037). The median OS in the EGFR-TKI continuation, EGFR-TKI continuation with chemotherapy, chemotherapy alone, and BSC groups were 6.9, 11.6, 8.8, and 0.9 months, respectively. Compared to the BSC group, the OS of all groups enjoyed a longer survival(P < 0.001).Conclusion A small portion of patients with resistance to EGFR-TKI may benefit from the combination of EGFR-TKI with chemotherapy. Patients who had good PS score and are capable of receiving continuing treatment should adopt combined treatment positively. |
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