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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

Deletion of Cebpb does not affect tumor burden in vivo.(A) Scheme of the strategy generating lung specific inducible EGFR-TL transgenic mice with Cebpb knockout background. (B) Genotype of EGFRTL/CCSP-rtTA/Cebpb+/+, CCSP-rtTA/Cebpb+/+ and EGFRTL/CCSP-rtTA/Cebpb-/- mice. (C) Representative images of H&E staining and immunohistochemistry of lungs isolated from EGFRTL/CCSPrtTA/Cebpb+/+(I and II) or EGFRTL/CCSPrtTA/Cebpb-/-(III and IV). Lung sections were stained with H&E (I and III) and anti-TTF1 (II and IV) antibodies. “A” indicates an area with bronchioalveolar growth pattern and “P” indicates an area with bronchial papillary growth pattern. (D) Lung weight isolated from mice treated with doxycycline for 8–12 weeks. We analyzed 5 CCSP-rtTA/Cebpb+/+, 5 EGFRTL/CCSP-rtTA/Cebpb+/+, and 11 EGFRTL/CCSP-rtTA/Cebpb-/- mice. Data represent mean ± standard deviation. ** denotes p ≤ 0.01. N.S. denotes not significant.
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pone.0120647.g005: Deletion of Cebpb does not affect tumor burden in vivo.(A) Scheme of the strategy generating lung specific inducible EGFR-TL transgenic mice with Cebpb knockout background. (B) Genotype of EGFRTL/CCSP-rtTA/Cebpb+/+, CCSP-rtTA/Cebpb+/+ and EGFRTL/CCSP-rtTA/Cebpb-/- mice. (C) Representative images of H&E staining and immunohistochemistry of lungs isolated from EGFRTL/CCSPrtTA/Cebpb+/+(I and II) or EGFRTL/CCSPrtTA/Cebpb-/-(III and IV). Lung sections were stained with H&E (I and III) and anti-TTF1 (II and IV) antibodies. “A” indicates an area with bronchioalveolar growth pattern and “P” indicates an area with bronchial papillary growth pattern. (D) Lung weight isolated from mice treated with doxycycline for 8–12 weeks. We analyzed 5 CCSP-rtTA/Cebpb+/+, 5 EGFRTL/CCSP-rtTA/Cebpb+/+, and 11 EGFRTL/CCSP-rtTA/Cebpb-/- mice. Data represent mean ± standard deviation. ** denotes p ≤ 0.01. N.S. denotes not significant.

Mentions: Our results from lung cancer cell lines suggest that C/EBPβ in tumor cells may not drive cell growth. However, these results should be confirmed in vivo. In addition, it is possible that C/EBPβ play an important role to maintain tumor microenvironment. Therefore, we generated the inducible EGFR T790M-L858R transgenic mouse model in Cebpb knockout background. We crossed two established mouse models, the lung specific EGFR-L858R-T790M (EGFRTL)/CCSP-rtTA bi-transgenic mice [27], and the C/EBPβ conventional knockout mice (Cebpb-/-) (Fig. 5A and 5B) [28]. Consistent with our previous report [27], TTF-1 positive lung adenocarcinomas developed in EGFRTL/CCSP-rtTA/Cebpb+/+mice (Fig. 5C; I and II) as well as in EGFRTL/CCSP-rtTA/Cebpb-/-mice (Fig. 5C; III and IV) when treated with doxycycline for 10 weeks. By histological analysis, the lung adenocarcinomas in EGFRTL/CCSP-rtTA/Cebpb-/- mice tended to demonstrate a more central bronchial papillary growth pattern (Fig. 5C; III), whereas the adenocarcinomas in EGFRTL/CCSP-rtTA/Cebpb+/+mice tended to have a more peripheral distribution with solid and bronchioalveolar growth features (Fig. 5C; I). However, no significant differences were noted regarding overall tumor burden as reflected by gross lung weights (Fig. 5D). These data suggest that C/EBPβ is dispensable for lung tumorigenesis in EGFR-driven murine lung cancer.


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)

Deletion of Cebpb does not affect tumor burden in vivo.(A) Scheme of the strategy generating lung specific inducible EGFR-TL transgenic mice with Cebpb knockout background. (B) Genotype of EGFRTL/CCSP-rtTA/Cebpb+/+, CCSP-rtTA/Cebpb+/+ and EGFRTL/CCSP-rtTA/Cebpb-/- mice. (C) Representative images of H&E staining and immunohistochemistry of lungs isolated from EGFRTL/CCSPrtTA/Cebpb+/+(I and II) or EGFRTL/CCSPrtTA/Cebpb-/-(III and IV). Lung sections were stained with H&E (I and III) and anti-TTF1 (II and IV) antibodies. “A” indicates an area with bronchioalveolar growth pattern and “P” indicates an area with bronchial papillary growth pattern. (D) Lung weight isolated from mice treated with doxycycline for 8–12 weeks. We analyzed 5 CCSP-rtTA/Cebpb+/+, 5 EGFRTL/CCSP-rtTA/Cebpb+/+, and 11 EGFRTL/CCSP-rtTA/Cebpb-/- mice. Data represent mean ± standard deviation. ** denotes p ≤ 0.01. 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.g005: Deletion of Cebpb does not affect tumor burden in vivo.(A) Scheme of the strategy generating lung specific inducible EGFR-TL transgenic mice with Cebpb knockout background. (B) Genotype of EGFRTL/CCSP-rtTA/Cebpb+/+, CCSP-rtTA/Cebpb+/+ and EGFRTL/CCSP-rtTA/Cebpb-/- mice. (C) Representative images of H&E staining and immunohistochemistry of lungs isolated from EGFRTL/CCSPrtTA/Cebpb+/+(I and II) or EGFRTL/CCSPrtTA/Cebpb-/-(III and IV). Lung sections were stained with H&E (I and III) and anti-TTF1 (II and IV) antibodies. “A” indicates an area with bronchioalveolar growth pattern and “P” indicates an area with bronchial papillary growth pattern. (D) Lung weight isolated from mice treated with doxycycline for 8–12 weeks. We analyzed 5 CCSP-rtTA/Cebpb+/+, 5 EGFRTL/CCSP-rtTA/Cebpb+/+, and 11 EGFRTL/CCSP-rtTA/Cebpb-/- mice. Data represent mean ± standard deviation. ** denotes p ≤ 0.01. N.S. denotes not significant.
Mentions: Our results from lung cancer cell lines suggest that C/EBPβ in tumor cells may not drive cell growth. However, these results should be confirmed in vivo. In addition, it is possible that C/EBPβ play an important role to maintain tumor microenvironment. Therefore, we generated the inducible EGFR T790M-L858R transgenic mouse model in Cebpb knockout background. We crossed two established mouse models, the lung specific EGFR-L858R-T790M (EGFRTL)/CCSP-rtTA bi-transgenic mice [27], and the C/EBPβ conventional knockout mice (Cebpb-/-) (Fig. 5A and 5B) [28]. Consistent with our previous report [27], TTF-1 positive lung adenocarcinomas developed in EGFRTL/CCSP-rtTA/Cebpb+/+mice (Fig. 5C; I and II) as well as in EGFRTL/CCSP-rtTA/Cebpb-/-mice (Fig. 5C; III and IV) when treated with doxycycline for 10 weeks. By histological analysis, the lung adenocarcinomas in EGFRTL/CCSP-rtTA/Cebpb-/- mice tended to demonstrate a more central bronchial papillary growth pattern (Fig. 5C; III), whereas the adenocarcinomas in EGFRTL/CCSP-rtTA/Cebpb+/+mice tended to have a more peripheral distribution with solid and bronchioalveolar growth features (Fig. 5C; I). However, no significant differences were noted regarding overall tumor burden as reflected by gross lung weights (Fig. 5D). These data suggest that C/EBPβ is dispensable for lung tumorigenesis in EGFR-driven murine lung cancer.

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