RESUMO
Objective:To determine the role of type Ⅱ alveolar epithelial stem cells (AEC Ⅱ) in radiation-induced pulmonary injury and investigate the potential mechanism by observing the dynamic changes in the expression levels of anti-prosurfactant protein C (proSP-C) proSP-C (AEC Ⅱ biomarker), homeobox only protein X (HOPX, type I alveolar epithelial cell biomarker) or vimentin (a mesenchymal marker) and transforming growth factor β 1(TGF-β 1), a profibrotic cytokine. Methods:Eight-week old C57BL/6j female mice were exposed to X-ray thoracic irradiation. Mouse lungs were collected at 8 different time points of 24 h, 1 week, 1 to 6 months after irradiation. The histopathological changes of the lungs at different time points were observed with H& E staining to determine the time of formation of pulmonary fibrosis. In addition, the co-expression of proSP-C with HOPX or vimentin in AEC Ⅱ was confirmed by immunofluorescence staining to track AEC Ⅱ phenotypes at different injury phases following thoracic irradiation. The expression levels of those proteins and TGF-β 1 were quantitatively detected by Western blot. Results:After thoracic exposure to a single dose of 20 Gy X-ray for 3 months, the fibrotic lesions in the lungs could be noted. The co-expression of proSP-C with vimentin or HOPX could be observed in AEC Ⅱ. Western blot demonstrated that the expression levels of TGF-β 1 and those proteins were also changed along with the lung injury. Conclusion:AEC Ⅱ can be differentiated into mesenchymal-like cells after X-ray irradiation due to the up-regulated expression of TGF-β 1, which is a potential cause of radiation-induced pulmonary fibrosis.
RESUMO
Background and purpose:Chemotherapy is an alternative treatment option, which could still get a therapeutic effect, when the EGFR-TKI treatment of non-small cell lung cancer failed. Studies have shown that RR, TYMS, ERCC1 and TUBB3 have respectively relationship with chemosensitivity of gemcitabine, pemetrexed, platinum-based drugs and microtubule-based chemotherapy drugs.The expression levels of these molecular markers can predict the sensitivity of these chemotherapy drugs. The patients with RRMI, TS, ERCC1 and TUBB3 higher expression have reduced chemosensitivity, and lower expression have increased sensitivity. The purpose of this study was to explore the sensitivity of tumor cell lines with acquired resistance to geiftinib caused byEGFR-T790M mutation to cisplatin, gemcitabine, pemetrexed, vinorelbine, paclitaxel and docetaxel.Methods:MTT assay was used to detect the IC50 values of cisplatin, gemcitabine, vinorelbine, paclitaxel and docetaxel, pemetrexed to PC9 and PC9/GR cells, and to explore the chemosensitivity of lung adenocarcinoma cells to these chemotherapy drugs; Luminex method was used respectively to detect the expression levels of ERCC1 mRNA, TUBB3 mRNA, TS mRNA, and RRM1 mRNA in PC9 and PC9/GR cells. Western blot was used to detect the protein expression levels of ERCC1, TUBB3, TS and RRM1 in PC9 and PC9/GR cells.Results: The IC50 values of cisplatin, gemcitabine and pemetrexed to PC9/GR cells were signiifcantly higher than those to PC9 cells (P<0.05), while the IC50 values of vinorelbine, paclitaxe and docetaxel to PC9/GR cells were signiifcantly decreased (P<0.05). Luminex method showed the expressions of ERCC1 mRNA, TS mRNA and RRM1 mRNA in PC9/GR cells were signiifcantly increased than those in PC9 cells (P<0.05), while the expression of TUBB3 mRNA was signiifcantly decreased (P<0.05). Western blot method showed the expressions of TUBB3, TS and RRM1 protein in PC9/GR cells were signiifcantly increased than those in PC9 cells (P<0.05), while TUBB3 protein expression in PC9/GR cells was signiifcantly decreased (P<0.05). Western blot method analysis result showed that the expressions of TUBB3, TS and RRM1 protein in PC9/GR cells were significantly increased than those in PC9 cells (P<0.05), while TUBB3 protein expression in PC9/GR cells was signiifcantly decreased (P<0.05). Conclusion:The chemosensitivity of lung adenocarcinoma with EGFR-T790M mutation is changed. It has decreased sensitivity to cisplatin, gemcitabine, pemetrexed and increased sensitivity to vinorelbine, paclitaxel and docetaxel. The reason of the change of chemosensitivity of geiftinib-resistant lung adenocarcinoma cell maybe related to the changes of ERCC1 mRNA, RRM1 mRNA and TS mRNA and their protein expressions.