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Growth inhibition of non-small cell lung cancer cells by AP-1 blockade using a cJun dominant-negative mutant.

Shimizu Y, Kinoshita I, Kikuchi J, Yamazaki K, Nishimura M, Birrer MJ, Dosaka-Akita H - Br. J. Cancer (2008)

Bottom Line: The colony-forming efficiency of H1299 and A549 was reduced by TAM67, while that of H520 was not.The induced TAM67 decreased the expression of a cell-cycle regulatory protein, cyclin A.Furthermore, TAM67 reduced growth of established xenograft tumours from these cells in nude mice.

View Article: PubMed Central - PubMed

Affiliation: Department of Medical Oncology, Hokkaido University Graduate School of Medicine, North 15, West 7, Kita-ku, Sapporo 060-8638, Japan.

ABSTRACT
cJun, a major constituent of AP-1 transcription factor transducing multiple mitogen growth signals, is frequently overexpressed in non-small cell lung cancers (NSCLCs). The purpose of this study is to determine the effects of AP-1 blockade on the growth of NSCLC cells using a cJun dominant-negative mutant, TAM67. Transiently transfected TAM67 inhibited AP-1 transcriptional activity in NSCLC cell lines, NCI-H1299 (H1299), A549 and NCI-H520 (H520). The colony-forming efficiency of H1299 and A549 was reduced by TAM67, while that of H520 was not. To elucidate the effects of TAM67 on the growth of H1299, we established H1299 clone cells that expressed TAM67 under the control of a doxycycline-inducible promoter. In the H1299 clone cells, the induced TAM67 inhibited anchorage-dependent growth by promoting G1 cell-cycle block, but not by apoptosis. The induced TAM67 decreased the expression of a cell-cycle regulatory protein, cyclin A. TAM67 also inhibited anchorage-independent growth of these cells. Furthermore, TAM67 reduced growth of established xenograft tumours from these cells in nude mice. These results suggest that AP-1 plays an essential role in the growth of at least some of NSCLC cells.

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Inhibition of AP-1 transcriptional activity by TAM67 in NSCLC cells. H1299, A549 and H520 cells were cotransfected with 0.1 μg of TRE2-luciferase plasmid and 8 ng of renilla-luciferase plasmid and either 0.2 μg of pCMV-TAM67 or pCMV control plasmid. Transfected cells were lysed 36 h after transfection and luciferase activity was measured. To increase AP-1 activity, cells were treated with 0.1 nM TPA for 6 h before harvesting. The luciferase activity was shown relative to the basal activity in H520 cotransfected with pCMV plasmid without TPA, which was set to 1. Each value represents the mean±s.d. (n=3). *P<0.01.
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fig1: Inhibition of AP-1 transcriptional activity by TAM67 in NSCLC cells. H1299, A549 and H520 cells were cotransfected with 0.1 μg of TRE2-luciferase plasmid and 8 ng of renilla-luciferase plasmid and either 0.2 μg of pCMV-TAM67 or pCMV control plasmid. Transfected cells were lysed 36 h after transfection and luciferase activity was measured. To increase AP-1 activity, cells were treated with 0.1 nM TPA for 6 h before harvesting. The luciferase activity was shown relative to the basal activity in H520 cotransfected with pCMV plasmid without TPA, which was set to 1. Each value represents the mean±s.d. (n=3). *P<0.01.

Mentions: To determine whether TAM67 inhibits AP-1 activity in NSCLC cells, H1299, A549 and H520, were cotransfected with TRE2- and renilla-luciferase vector and either TAM67 expression vector (pCMV-TAM67) or control vector (pCMV). The transiently transfected TAM67 inhibited AP-1 activity in these three cell lines similarly, while basal AP-1 activity in A549 and H1299 was about four- and fivefold higher, respectively, than that in H520 (Figure 1). TAM67 also inhibited TPA-induced AP-1 activity in these cells. These results indicate that TAM67 inhibits AP-1 transcriptional activity in NSCLC cells.


Growth inhibition of non-small cell lung cancer cells by AP-1 blockade using a cJun dominant-negative mutant.

Shimizu Y, Kinoshita I, Kikuchi J, Yamazaki K, Nishimura M, Birrer MJ, Dosaka-Akita H - Br. J. Cancer (2008)

Inhibition of AP-1 transcriptional activity by TAM67 in NSCLC cells. H1299, A549 and H520 cells were cotransfected with 0.1 μg of TRE2-luciferase plasmid and 8 ng of renilla-luciferase plasmid and either 0.2 μg of pCMV-TAM67 or pCMV control plasmid. Transfected cells were lysed 36 h after transfection and luciferase activity was measured. To increase AP-1 activity, cells were treated with 0.1 nM TPA for 6 h before harvesting. The luciferase activity was shown relative to the basal activity in H520 cotransfected with pCMV plasmid without TPA, which was set to 1. Each value represents the mean±s.d. (n=3). *P<0.01.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2266861&req=5

fig1: Inhibition of AP-1 transcriptional activity by TAM67 in NSCLC cells. H1299, A549 and H520 cells were cotransfected with 0.1 μg of TRE2-luciferase plasmid and 8 ng of renilla-luciferase plasmid and either 0.2 μg of pCMV-TAM67 or pCMV control plasmid. Transfected cells were lysed 36 h after transfection and luciferase activity was measured. To increase AP-1 activity, cells were treated with 0.1 nM TPA for 6 h before harvesting. The luciferase activity was shown relative to the basal activity in H520 cotransfected with pCMV plasmid without TPA, which was set to 1. Each value represents the mean±s.d. (n=3). *P<0.01.
Mentions: To determine whether TAM67 inhibits AP-1 activity in NSCLC cells, H1299, A549 and H520, were cotransfected with TRE2- and renilla-luciferase vector and either TAM67 expression vector (pCMV-TAM67) or control vector (pCMV). The transiently transfected TAM67 inhibited AP-1 activity in these three cell lines similarly, while basal AP-1 activity in A549 and H1299 was about four- and fivefold higher, respectively, than that in H520 (Figure 1). TAM67 also inhibited TPA-induced AP-1 activity in these cells. These results indicate that TAM67 inhibits AP-1 transcriptional activity in NSCLC cells.

Bottom Line: The colony-forming efficiency of H1299 and A549 was reduced by TAM67, while that of H520 was not.The induced TAM67 decreased the expression of a cell-cycle regulatory protein, cyclin A.Furthermore, TAM67 reduced growth of established xenograft tumours from these cells in nude mice.

View Article: PubMed Central - PubMed

Affiliation: Department of Medical Oncology, Hokkaido University Graduate School of Medicine, North 15, West 7, Kita-ku, Sapporo 060-8638, Japan.

ABSTRACT
cJun, a major constituent of AP-1 transcription factor transducing multiple mitogen growth signals, is frequently overexpressed in non-small cell lung cancers (NSCLCs). The purpose of this study is to determine the effects of AP-1 blockade on the growth of NSCLC cells using a cJun dominant-negative mutant, TAM67. Transiently transfected TAM67 inhibited AP-1 transcriptional activity in NSCLC cell lines, NCI-H1299 (H1299), A549 and NCI-H520 (H520). The colony-forming efficiency of H1299 and A549 was reduced by TAM67, while that of H520 was not. To elucidate the effects of TAM67 on the growth of H1299, we established H1299 clone cells that expressed TAM67 under the control of a doxycycline-inducible promoter. In the H1299 clone cells, the induced TAM67 inhibited anchorage-dependent growth by promoting G1 cell-cycle block, but not by apoptosis. The induced TAM67 decreased the expression of a cell-cycle regulatory protein, cyclin A. TAM67 also inhibited anchorage-independent growth of these cells. Furthermore, TAM67 reduced growth of established xenograft tumours from these cells in nude mice. These results suggest that AP-1 plays an essential role in the growth of at least some of NSCLC cells.

Show MeSH
Related in: MedlinePlus