Genomic Study of Radiation-Induced Transcriptional Responses and the Role of Jagged 1 in Two Closely-Related ung Cancer Cell Lines
Date Issued
2008
Date
2008
Author(s)
Kang, Yu
Abstract
Lung cancer is the most common and lethal cancer in the world. NSCLC accounts for 80% lung cancer patients, and the 5-year survival rate after radiotherapy is about 5% whether the patients are with less or more extensive tumors. However, the mechanism behind radiation response of lung cancer is still not clear. Here, lung adenocarcinoma cell lines CL1-0 and CL1-5 with different metastasis abilities were used as the objects of our in vitro study. The aim of this thesis was to investigate the radiosensitivity in CL1-0 and CL1-5 via global gene expression profiles and the role of a notch ligand, Jagged 1 played in radiosensitivity. Clonogenic assay was used to obtain radio sensitivity in CL1-0 and CL1-5. To better understand the cell cycle distributions followed by radiation, flow cytometry experiment was performed at different time points. At the same time, the temporal global gene expression profile was obtained to understand the radiosenstivity via global transcriptional activities. In addition, the expression difference of Jagged 1 between CL1-0 and CL1-5 were significant in microarray, and were further confirmed by real time PCR and western blotting. To investigate the role of Jagged 1 in radiosensitivity, Jagged 1 overexpressed CL1-0 was obtained to perform functional assay. The data indicated that CL1-5 was more radiosensitive than CL1-0 after 10 Gy radiation. The irradiated CL1-0 and CL1-5 exhibited G2/M blockade and with the lack of G1/S checkpoint. Moreover, the subG1 area was significantly higher in the irradiated CL1-0 than the CL1-5 cells. From microarray data and through tight clustering analysis, there were six clusters expressed significantly different between CL1-0 and CL1-5. Genes among them were related to cell death, cell cycle, cell growth and proliferation, cellular function and maintenance. A different expression gene group between CL1-0 and CL1-5 showed genes related to G2/M checkpoint, which was consistent with the G2/M arrest activities. The Jagged 1 functional assay results showed an increasing survival rate in Jagged 1 overexpressed CL1-0 compared to CL1-0.Also, the transcription level of NFκBIA were changed in Jagged 1 overexpressed CL1-0. Compared to CL1-0 and CL1-5, Jagged 1 overexpressed CL1-0 cell line showed a mid percentage in sub G1 and G2/M phase. In conclusion, CL1-5 was more radio sensitive than CL1-0 and the death cause was mainly from mitotic death. In addition, Jagged 1 was associated partially with the radiosenstivity in CL1-0 and CL1-5, and may have a cross talk with NFκBIA.
Subjects
lung cancer
radiation
radiosensitivity
microarray
SDGs
Type
thesis
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