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Nuclear Receptor Expression and Function in Human Lung Cancer Pathogenesis.

Kim J, Sato M, Choi JW, Kim HW, Yeh BI, Larsen JE, Minna JD, Cha JH, Jeong Y - PLoS ONE (2015)

Bottom Line: Notably, PPARγ activation by thiazolidinedione (TZD) treatment reversed the increased expression of pro-inflammatory cyclooxygenase 2 (COX2) in precancerous HBECs.In fully tumorigenic HBECs with inducible expression of PPARγ, TZD treatments inhibited tumor cell growth, clonogenecity, and cell migration in a PPARγ-sumoylation dependent manner.Mechanistically, the sumoylation of liganded-PPARγ decreased COX2 expression and increased 15-hydroxyprostaglandin dehydrogenase expression.

View Article: PubMed Central - PubMed

Affiliation: Department of Biochemistry, Wonju College of Medicine, Yonsei University, Wonju, Gangwon-do, Republic of Korea; Institute of Lifestyle Medicine, Wonju College of Medicine, Yonsei University, Wonju, Gangwon-do, Republic of Korea; Nuclear Receptor Research Consortium, Wonju College of Medicine, Yonsei University, Wonju, Gangwon-do, Republic of Korea.

ABSTRACT
Lung cancer is caused by combinations of diverse genetic mutations. Here, to understand the relevance of nuclear receptors (NRs) in the oncogene-associated lung cancer pathogenesis, we investigated the expression profile of the entire 48 NR members by using QPCR analysis in a panel of human bronchial epithelial cells (HBECs) that included precancerous and tumorigenic HBECs harboring oncogenic K-rasV12 and/or p53 alterations. The analysis of the profile revealed that oncogenic alterations accompanied transcriptional changes in the expression of 19 NRs in precancerous HBECs and 15 NRs according to the malignant progression of HBECs. Amongst these, peroxisome proliferator-activated receptor gamma (PPARγ), a NR chosen as a proof-of-principle study, showed increased expression in precancerous HBECs, which was surprisingly reversed when these HBECs acquired full in vivo tumorigenicity. Notably, PPARγ activation by thiazolidinedione (TZD) treatment reversed the increased expression of pro-inflammatory cyclooxygenase 2 (COX2) in precancerous HBECs. In fully tumorigenic HBECs with inducible expression of PPARγ, TZD treatments inhibited tumor cell growth, clonogenecity, and cell migration in a PPARγ-sumoylation dependent manner. Mechanistically, the sumoylation of liganded-PPARγ decreased COX2 expression and increased 15-hydroxyprostaglandin dehydrogenase expression. This suggests that ligand-mediated sumoylation of PPARγ plays an important role in lung cancer pathogenesis by modulating prostaglandin metabolism.

No MeSH data available.


Related in: MedlinePlus

Characterization of tumorigenic HBEC clones.(A) Histologic analysis of tumorigenic clones; C1 tumor poorly differentiated carcinoma with large cells suggestive of squamous cell carcinoma (H&E, x40) (left) and C5 tumor poorly differentiated carcinoma with features of adenocarcinoma (H&E, x40) (right). (B) In vitro characterization of HBEC tumorigenic clones C1 and C5. Immunoblot assays were performed using antibodies against K-ras, p53, pERK, total ERK, and beta-actin in tumorigenic HBEC clones. Using QPCR assay, the mRNA expression of PPARγ was measured in tumorigenic clones (bottom in B). (C) Growth response of tumorigenic HBEC clones to the combined treatment of PPARγ (3 μM troglitazone) and RXR (100 nM LG268) ligands. Data represent the mean ± SD (n = 3). Asterisks show a statistically significant point as evaluated by ANOVA. * P < 0.001 compared to HBEC-KT control.
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pone.0134842.g004: Characterization of tumorigenic HBEC clones.(A) Histologic analysis of tumorigenic clones; C1 tumor poorly differentiated carcinoma with large cells suggestive of squamous cell carcinoma (H&E, x40) (left) and C5 tumor poorly differentiated carcinoma with features of adenocarcinoma (H&E, x40) (right). (B) In vitro characterization of HBEC tumorigenic clones C1 and C5. Immunoblot assays were performed using antibodies against K-ras, p53, pERK, total ERK, and beta-actin in tumorigenic HBEC clones. Using QPCR assay, the mRNA expression of PPARγ was measured in tumorigenic clones (bottom in B). (C) Growth response of tumorigenic HBEC clones to the combined treatment of PPARγ (3 μM troglitazone) and RXR (100 nM LG268) ligands. Data represent the mean ± SD (n = 3). Asterisks show a statistically significant point as evaluated by ANOVA. * P < 0.001 compared to HBEC-KT control.

Mentions: Since different levels of PPARγ expression reflected no difference in growth inhibition of non-tumorigenic HBECs when treated with troglitazone (Fig 3C), we wondered if the transformed HBECs show a different response to the PPARγ ligand treatment and distinct expression patterns of other NRs compared to the pre-cancerous HBECs. We first characterized the two tumorigenic clones, HBEC-C1 and -C5, at the cellular and tissue levels. Histological characterization of the xenograft tumors revealed, as shown recently by us, that HBEC-KT with p53 knockdown and K-rasV12 high expression manipulation could lead to clonal derivatives with different histologies- squamous cell carcinoma (SCC, HBEC-C1) and adenocarcinoma (ADK, HBEC-C5) [31](Fig 4A). Biochemical analysis confirmed that both oncogenic alterations, K-rasV12 activity as well as loss of p53 expression, were equally maintained in the tumorigenic HBEC-C1 and -C5 clones (Fig 4B). Surprisingly, both PPARγ and COX2 expressions were dramatically decreased in tumorigenic HBEC clones (Fig 4B and S3 Fig) and the tumorigenic clones were consistently resistant to PPARγ growth inhibition (Fig 4C). These data suggest the possibility that during premalignancy driven by p53 and K-ras oncogenic changes that PPARγ and COX2 can be therapeutic targets but that with the development of full malignancy that the tumors bypass this control, which in some cases occurs by down regulation of PPARγ. Such findings would be consistent with reports that the use of non-steroidal anti-inflammatory drug (NSAID) can protect against the development of lung cancer in men while their use in fully developed lung cancers appears not to be therapeutic [40].


Nuclear Receptor Expression and Function in Human Lung Cancer Pathogenesis.

Kim J, Sato M, Choi JW, Kim HW, Yeh BI, Larsen JE, Minna JD, Cha JH, Jeong Y - PLoS ONE (2015)

Characterization of tumorigenic HBEC clones.(A) Histologic analysis of tumorigenic clones; C1 tumor poorly differentiated carcinoma with large cells suggestive of squamous cell carcinoma (H&E, x40) (left) and C5 tumor poorly differentiated carcinoma with features of adenocarcinoma (H&E, x40) (right). (B) In vitro characterization of HBEC tumorigenic clones C1 and C5. Immunoblot assays were performed using antibodies against K-ras, p53, pERK, total ERK, and beta-actin in tumorigenic HBEC clones. Using QPCR assay, the mRNA expression of PPARγ was measured in tumorigenic clones (bottom in B). (C) Growth response of tumorigenic HBEC clones to the combined treatment of PPARγ (3 μM troglitazone) and RXR (100 nM LG268) ligands. Data represent the mean ± SD (n = 3). Asterisks show a statistically significant point as evaluated by ANOVA. * P < 0.001 compared to HBEC-KT control.
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getmorefigures.php?uid=PMC4526668&req=5

pone.0134842.g004: Characterization of tumorigenic HBEC clones.(A) Histologic analysis of tumorigenic clones; C1 tumor poorly differentiated carcinoma with large cells suggestive of squamous cell carcinoma (H&E, x40) (left) and C5 tumor poorly differentiated carcinoma with features of adenocarcinoma (H&E, x40) (right). (B) In vitro characterization of HBEC tumorigenic clones C1 and C5. Immunoblot assays were performed using antibodies against K-ras, p53, pERK, total ERK, and beta-actin in tumorigenic HBEC clones. Using QPCR assay, the mRNA expression of PPARγ was measured in tumorigenic clones (bottom in B). (C) Growth response of tumorigenic HBEC clones to the combined treatment of PPARγ (3 μM troglitazone) and RXR (100 nM LG268) ligands. Data represent the mean ± SD (n = 3). Asterisks show a statistically significant point as evaluated by ANOVA. * P < 0.001 compared to HBEC-KT control.
Mentions: Since different levels of PPARγ expression reflected no difference in growth inhibition of non-tumorigenic HBECs when treated with troglitazone (Fig 3C), we wondered if the transformed HBECs show a different response to the PPARγ ligand treatment and distinct expression patterns of other NRs compared to the pre-cancerous HBECs. We first characterized the two tumorigenic clones, HBEC-C1 and -C5, at the cellular and tissue levels. Histological characterization of the xenograft tumors revealed, as shown recently by us, that HBEC-KT with p53 knockdown and K-rasV12 high expression manipulation could lead to clonal derivatives with different histologies- squamous cell carcinoma (SCC, HBEC-C1) and adenocarcinoma (ADK, HBEC-C5) [31](Fig 4A). Biochemical analysis confirmed that both oncogenic alterations, K-rasV12 activity as well as loss of p53 expression, were equally maintained in the tumorigenic HBEC-C1 and -C5 clones (Fig 4B). Surprisingly, both PPARγ and COX2 expressions were dramatically decreased in tumorigenic HBEC clones (Fig 4B and S3 Fig) and the tumorigenic clones were consistently resistant to PPARγ growth inhibition (Fig 4C). These data suggest the possibility that during premalignancy driven by p53 and K-ras oncogenic changes that PPARγ and COX2 can be therapeutic targets but that with the development of full malignancy that the tumors bypass this control, which in some cases occurs by down regulation of PPARγ. Such findings would be consistent with reports that the use of non-steroidal anti-inflammatory drug (NSAID) can protect against the development of lung cancer in men while their use in fully developed lung cancers appears not to be therapeutic [40].

Bottom Line: Notably, PPARγ activation by thiazolidinedione (TZD) treatment reversed the increased expression of pro-inflammatory cyclooxygenase 2 (COX2) in precancerous HBECs.In fully tumorigenic HBECs with inducible expression of PPARγ, TZD treatments inhibited tumor cell growth, clonogenecity, and cell migration in a PPARγ-sumoylation dependent manner.Mechanistically, the sumoylation of liganded-PPARγ decreased COX2 expression and increased 15-hydroxyprostaglandin dehydrogenase expression.

View Article: PubMed Central - PubMed

Affiliation: Department of Biochemistry, Wonju College of Medicine, Yonsei University, Wonju, Gangwon-do, Republic of Korea; Institute of Lifestyle Medicine, Wonju College of Medicine, Yonsei University, Wonju, Gangwon-do, Republic of Korea; Nuclear Receptor Research Consortium, Wonju College of Medicine, Yonsei University, Wonju, Gangwon-do, Republic of Korea.

ABSTRACT
Lung cancer is caused by combinations of diverse genetic mutations. Here, to understand the relevance of nuclear receptors (NRs) in the oncogene-associated lung cancer pathogenesis, we investigated the expression profile of the entire 48 NR members by using QPCR analysis in a panel of human bronchial epithelial cells (HBECs) that included precancerous and tumorigenic HBECs harboring oncogenic K-rasV12 and/or p53 alterations. The analysis of the profile revealed that oncogenic alterations accompanied transcriptional changes in the expression of 19 NRs in precancerous HBECs and 15 NRs according to the malignant progression of HBECs. Amongst these, peroxisome proliferator-activated receptor gamma (PPARγ), a NR chosen as a proof-of-principle study, showed increased expression in precancerous HBECs, which was surprisingly reversed when these HBECs acquired full in vivo tumorigenicity. Notably, PPARγ activation by thiazolidinedione (TZD) treatment reversed the increased expression of pro-inflammatory cyclooxygenase 2 (COX2) in precancerous HBECs. In fully tumorigenic HBECs with inducible expression of PPARγ, TZD treatments inhibited tumor cell growth, clonogenecity, and cell migration in a PPARγ-sumoylation dependent manner. Mechanistically, the sumoylation of liganded-PPARγ decreased COX2 expression and increased 15-hydroxyprostaglandin dehydrogenase expression. This suggests that ligand-mediated sumoylation of PPARγ plays an important role in lung cancer pathogenesis by modulating prostaglandin metabolism.

No MeSH data available.


Related in: MedlinePlus