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CCAAT/enhancer binding protein β is dispensable for development of lung adenocarcinoma.

Cai Y, Hirata A, Nakayama S, VanderLaan PA, Levantini E, Yamamoto M, Hirai H, Wong KK, Costa DB, Watanabe H, Kobayashi SS - PLoS ONE (2015)

Bottom Line: We found that overall lung architecture was maintained in Cebpb knockout mice.Neither overexpression of nuclear C/EBPβ nor suppression of CEBPB expression had significant effects on cell proliferation.Taken together, our data suggest that C/EBPβ is dispensable for development of lung adenocarcinoma.

View Article: PubMed Central - PubMed

Affiliation: Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, United States of America.

ABSTRACT
Lung cancer is the leading cause of cancer death worldwide. Although disruption of normal proliferation and differentiation is a vital component of tumorigenesis, the mechanisms of this process in lung cancer are still unclear. A transcription factor, C/EBPβ is a critical regulator of proliferation and/or differentiation in multiple tissues. In lung, C/EBPβ is expressed in alveolar pneumocytes and bronchial epithelial cells; however, its roles on normal lung homeostasis and lung cancer development have not been well described. Here we investigated whether C/EBPβ is required for normal lung development and whether its aberrant expression and/or activity contribute to lung tumorigenesis. We showed that C/EBPβ was expressed in both human normal pneumocytes and lung adenocarcinoma cell lines. We found that overall lung architecture was maintained in Cebpb knockout mice. Neither overexpression of nuclear C/EBPβ nor suppression of CEBPB expression had significant effects on cell proliferation. C/EBPβ expression and activity remained unchanged upon EGF stimulation. Furthermore, deletion of Cebpb had no impact on lung tumor burden in a lung specific, conditional mutant EGFR lung cancer mouse model. Analyses of data from The Cancer Genome Atlas (TCGA) revealed that expression, promoter methylation, or copy number of CEBPB was not significantly altered in human lung adenocarcinoma. Taken together, our data suggest that C/EBPβ is dispensable for development of lung adenocarcinoma.

No MeSH data available.


Related in: MedlinePlus

EGF does not increase LIP protein.(A) Immunoblots of C/EBPβ in NCI-H1975 (EGFR L858R+T790M) and A549 (KRAS G12S) lung adenocarcinoma cells treated with EGF in the presence or absence of EGFR kinase inhibitors for 24 hours. Changes in LIP expression are adjusted by β-actin expression and expressed as fold increase relative to that of PBS-treated cells. Note that the full and LAP forms were detected in the gel exposed for 15 seconds, whereas LIP forms were detected after 1-hourr exposure of the gel. (B) Luciferase assay to determine C/EBPβ transcriptional activity. NCI-H1975 and A549 cells transfected with C/ebpb0.3-luc reporter and pCMV-Renilla control plasmid were assayed after 24 hours of treatment with EGF or PBS control. Data represents mean ± standard deviation from four independent experiments. N.S. denotes not significant.
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pone.0120647.g004: EGF does not increase LIP protein.(A) Immunoblots of C/EBPβ in NCI-H1975 (EGFR L858R+T790M) and A549 (KRAS G12S) lung adenocarcinoma cells treated with EGF in the presence or absence of EGFR kinase inhibitors for 24 hours. Changes in LIP expression are adjusted by β-actin expression and expressed as fold increase relative to that of PBS-treated cells. Note that the full and LAP forms were detected in the gel exposed for 15 seconds, whereas LIP forms were detected after 1-hourr exposure of the gel. (B) Luciferase assay to determine C/EBPβ transcriptional activity. NCI-H1975 and A549 cells transfected with C/ebpb0.3-luc reporter and pCMV-Renilla control plasmid were assayed after 24 hours of treatment with EGF or PBS control. Data represents mean ± standard deviation from four independent experiments. N.S. denotes not significant.

Mentions: In breast cancer, EGF stimulation has been shown to reduce C/EBPβ activity by increasing LIP [33]. Therefore, we asked whether C/EBPβ activity can be regulated by the EGFR signaling pathway in the lung cancer cells. To this end, we examined two cell lines, NCI-H1975 and A549 cells, which harbor the EGFR L858R+T790M double mutations and KRAS G12S mutation, respectively. When these cells were treated with EGF in the presence or absence of EGFR tyrosine kinase inhibitors (erlotinib or afatinib), no apparent changes in expression of C/EBPβ LIP isoform were detected (Fig. 4A). Consistent with these results, EGF stimulation led to no significant change in C/EBPβ activity determined by luciferase assay in these two cell lines (Fig. 4B). Therefore, it appears unlikely that EGFR signaling mediates C/EBPβ activity in lung cancer cells.


CCAAT/enhancer binding protein β is dispensable for development of lung adenocarcinoma.

Cai Y, Hirata A, Nakayama S, VanderLaan PA, Levantini E, Yamamoto M, Hirai H, Wong KK, Costa DB, Watanabe H, Kobayashi SS - PLoS ONE (2015)

EGF does not increase LIP protein.(A) Immunoblots of C/EBPβ in NCI-H1975 (EGFR L858R+T790M) and A549 (KRAS G12S) lung adenocarcinoma cells treated with EGF in the presence or absence of EGFR kinase inhibitors for 24 hours. Changes in LIP expression are adjusted by β-actin expression and expressed as fold increase relative to that of PBS-treated cells. Note that the full and LAP forms were detected in the gel exposed for 15 seconds, whereas LIP forms were detected after 1-hourr exposure of the gel. (B) Luciferase assay to determine C/EBPβ transcriptional activity. NCI-H1975 and A549 cells transfected with C/ebpb0.3-luc reporter and pCMV-Renilla control plasmid were assayed after 24 hours of treatment with EGF or PBS control. Data represents mean ± standard deviation from four independent experiments. N.S. denotes not significant.
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4358974&req=5

pone.0120647.g004: EGF does not increase LIP protein.(A) Immunoblots of C/EBPβ in NCI-H1975 (EGFR L858R+T790M) and A549 (KRAS G12S) lung adenocarcinoma cells treated with EGF in the presence or absence of EGFR kinase inhibitors for 24 hours. Changes in LIP expression are adjusted by β-actin expression and expressed as fold increase relative to that of PBS-treated cells. Note that the full and LAP forms were detected in the gel exposed for 15 seconds, whereas LIP forms were detected after 1-hourr exposure of the gel. (B) Luciferase assay to determine C/EBPβ transcriptional activity. NCI-H1975 and A549 cells transfected with C/ebpb0.3-luc reporter and pCMV-Renilla control plasmid were assayed after 24 hours of treatment with EGF or PBS control. Data represents mean ± standard deviation from four independent experiments. N.S. denotes not significant.
Mentions: In breast cancer, EGF stimulation has been shown to reduce C/EBPβ activity by increasing LIP [33]. Therefore, we asked whether C/EBPβ activity can be regulated by the EGFR signaling pathway in the lung cancer cells. To this end, we examined two cell lines, NCI-H1975 and A549 cells, which harbor the EGFR L858R+T790M double mutations and KRAS G12S mutation, respectively. When these cells were treated with EGF in the presence or absence of EGFR tyrosine kinase inhibitors (erlotinib or afatinib), no apparent changes in expression of C/EBPβ LIP isoform were detected (Fig. 4A). Consistent with these results, EGF stimulation led to no significant change in C/EBPβ activity determined by luciferase assay in these two cell lines (Fig. 4B). Therefore, it appears unlikely that EGFR signaling mediates C/EBPβ activity in lung cancer cells.

Bottom Line: We found that overall lung architecture was maintained in Cebpb knockout mice.Neither overexpression of nuclear C/EBPβ nor suppression of CEBPB expression had significant effects on cell proliferation.Taken together, our data suggest that C/EBPβ is dispensable for development of lung adenocarcinoma.

View Article: PubMed Central - PubMed

Affiliation: Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, United States of America.

ABSTRACT
Lung cancer is the leading cause of cancer death worldwide. Although disruption of normal proliferation and differentiation is a vital component of tumorigenesis, the mechanisms of this process in lung cancer are still unclear. A transcription factor, C/EBPβ is a critical regulator of proliferation and/or differentiation in multiple tissues. In lung, C/EBPβ is expressed in alveolar pneumocytes and bronchial epithelial cells; however, its roles on normal lung homeostasis and lung cancer development have not been well described. Here we investigated whether C/EBPβ is required for normal lung development and whether its aberrant expression and/or activity contribute to lung tumorigenesis. We showed that C/EBPβ was expressed in both human normal pneumocytes and lung adenocarcinoma cell lines. We found that overall lung architecture was maintained in Cebpb knockout mice. Neither overexpression of nuclear C/EBPβ nor suppression of CEBPB expression had significant effects on cell proliferation. C/EBPβ expression and activity remained unchanged upon EGF stimulation. Furthermore, deletion of Cebpb had no impact on lung tumor burden in a lung specific, conditional mutant EGFR lung cancer mouse model. Analyses of data from The Cancer Genome Atlas (TCGA) revealed that expression, promoter methylation, or copy number of CEBPB was not significantly altered in human lung adenocarcinoma. Taken together, our data suggest that C/EBPβ is dispensable for development of lung adenocarcinoma.

No MeSH data available.


Related in: MedlinePlus