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S.J. Kim
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P1.04 - Poster Session/ Biology, Pathology, and Molecular Testing (ID 233)
- Event: WCLC 2015
- Type: Poster
- Track: Biology, Pathology, and Molecular Testing
- Presentations: 2
- Moderators:
- Coordinates: 9/07/2015, 09:30 - 17:00, Exhibit Hall (Hall B+C)
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P1.04-048 - DNA Demethylation Related Hypoxia-Induced Stem-Like Properties in Lung Cancer (ID 614)
09:30 - 17:00 | Author(s): S.J. Kim
- Abstract
Background:
Tumors exhibiting extensive hypoxia have been shown to be more aggressive than corresponding tumors that are better oxygenized, which suggests that hypoxic condition induces stem-like properties. The purpose of the present study was to investigate whether hypoxic stress induces acquisition of stem-like properties, and the mechanism is involved with DNA demethylation in lung cancer.
Methods:
Normal epithelial cell line (BEAS-2B) and human lung cancer cell lines (A549, H292, H226 and H460) were incubated either in normoxic or in hypoxic (below 1% O~2~) condition. The cell lines were treated with a DNA methyltransferase inhibitor (5-azacytidine, AZA) to determine whether the expression of stem cell markers (CD44, CD133, CXCR4, ABCG2, CD117, ALDH1A1, EpCAM, CD90, Oct4, Nanog, SOX2, SSEA4 and CD166) was reactivated. Methylation-specific PCR and bisulfite sequencing were used to analyze the methylation status, and real-time RT-PCR and western blotting were performed to analyze the expression of the stem cell markers. Cell migration and Matrigel invasion assay were performed for functional analysis
Results:
Among the 13 stem cell markers, CXCR4, Oct4 and Nanog were increased at least one lung cancer cell line in hypoxic condition compared with in normoxic condition. These three stem cell markers were reactivated by treatment with AZA. Methylation-specific PCR showed decreased promoter methylation of these three stem cell markers in hypoxic condition compared with in normoxic condition, which was further validated by bisulfite sequencing. Migration and invasion were increase in hypoxic condition compared with in normoxic condition
Conclusion:
These results suggest that under the hypoxic condition, reactivation of stem-like properties was related with promoter demethylation of stem cell markers. Further studies are needed to assess its value as a prognostic factor and potential therapeutic applications.
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P1.04-052 - TGF-β Induced EMT and Stem-Like Characteristics in Lung Cancer (ID 109)
09:30 - 17:00 | Author(s): S.J. Kim
- Abstract
Background:
TGF-β promotes tumor invasion and metastasis by inducing an epithelial-mesenchymal transition (EMT). EMT is often associated with acquisition of stem-like characteristics. In the present study, we investigated whether EMT induced by TGF-β could acquire stem-like characteristics in lung cancer.
Methods:
Normal epithelial cell line (BEAS-2B) and lung cancer cell lines (A549, H292, H226 and H460) were used in the study. These cell lines were incubated with 10 ng/ml of TGF-β for 3 days. Western blot was performed to analyze the expression of epithelial marker (E-cadherin) and mesenchymal markers (N-cadherin, vimentin, fibronectin and alpha-smooth muscle actin). Real-time RT-PCR and western blot were performed to analyze the expression of stem cell markers (CD44, CD133, CXCR4, ABCG2, CD117, ALDH1A1, EpCAM, CD90, Oct4, Nanog, SOX2, SSEA4, and CD166). Wound-healing assay, Matrigel invasion assay and sphere formation assay were used to assess functional characteristics of EMT and stemness acquisition.
Results:
TGF-β induced EMT and stem cell markers with variable degrees according to lung cancer cell lines. Most of the stem cell markers were increased by treatment with TGF-β except H460 cell line. Increased expression of mesenchymal markers was associated with the acquisition of stem cell makers. Migration, invasion and sphere formation were increased according to the expression of stem cell markers.
Conclusion:
TGF-β induced EMT was associated with acquisition of stem-like characteristics which was different according to lung cancer cell lines. Further studies are needed to investigate the signal mechanism of EMT and stemness acquisition.
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P3.04 - Poster Session/ Biology, Pathology, and Molecular Testing (ID 235)
- Event: WCLC 2015
- Type: Poster
- Track: Biology, Pathology, and Molecular Testing
- Presentations: 1
- Moderators:
- Coordinates: 9/09/2015, 09:30 - 17:00, Exhibit Hall (Hall B+C)
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P3.04-098 - Bis Expression in Patients with Surgically Resected Lung Cancer and Its Clinical Significance (ID 617)
09:30 - 17:00 | Author(s): S.J. Kim
- Abstract
Background:
Bis, also known as BAG3, has been identified as a Bcl-2-interacting protein that enhances cellular anti-apoptotic activity. It is involved in cellular differentiation, angiogenesis, migration, and invasion in various tumors. The purpose of this study was to investigate the Bis expression pattern, and the clinical significance thereof, in patients with resected lung cancer.
Methods:
We studied 121 lung cancer patients who underwent curative surgical resection. Patient clinicopathological characteristics were reviewed retrospectively from medical records, including tumor recurrence and survival. The expression of Bis protein in lung cancer tissues was evaluated by immunohistochemical staining and was assessed using a four-tiered intensity score system (negative, weak, moderate, strong). Enhanced Bis expression at the periphery of a tumor facing the adjacent non-tumor region was referred as ‘marginal activity.’
Results:
Although Bis expression was higher in squamous cell carcinoma than in adenocarcinoma, marginal activity was higher in adenocarcinoma than in squamous cell carcinoma. All of the small cell carcinomas and lung cancer with neuroendocrine differentiation examined were negative for Bis expression. Compared with stage I lung cancer, patients with stage II and IIIA lung cancer exhibited higher Bis protein levels in lung tissues. Recurrence and survival rates did not differ significantly according to Bis expression intensity score or marginal activity.
Conclusion:
Our study demonstrated that Bis expression differed according to the histological type and pathological stage of the lung cancer. Further studies are needed to assess its use as a biomarker and its role in the molecular pathogenesis of lung cancer.
