BMP4 signaling induces senescence and modulates the oncogenic phenotype of A549 lung adenocarcinoma cells.
Lung cancer is the most common visceral malignancy in males, with rapidly increasing incidence in females, and a devastatingly poor prognosis. Transforming growth factor (TGF)-beta has been shown to induce senescence in A549 lung cancer cells, and both TGF-beta and bone morphogenetic protein (BMP) 2 can suppress the transformed phenotype of A549 cells in vitro. We examined the effects of BMP4, another member of the TGF-beta superfamily, on specific oncogenic properties of A549 cancer cells. When A549 cancer cells were treated continuously with 100 ng/ml of BMP4, a senescent phenotype was observed after 2 wk of treatment. The BMP-treated cells appeared larger than untreated cells, grew more slowly, had more senescence-associated beta-galactosidase activity, and had less telomerase activity, as measured by the telomeric repeat amplification protocol assay. Invasion through Engelbreth Holm-Swarm matrix was inhibited in the senescent cell population. Senescent BMP4-treated cells had lower ERK activation, VEGF expression, and Bcl2 expression than wild-type cells, consistent with a less proliferative, less angiogenic phenotype with increased susceptibility to death by apoptosis. BMP4 treatment also resulted in sustained elevation of Smad1. In vivo xenograft studies in the flanks of nude mice confirmed that the BMP-treated cells were significantly less tumorigenic than untreated cells. Direct overexpression of Smad1 using adenoviral constructs resulted in cell death within 5 days. These studies suggest that BMP4 pathway signaling can induce senescence and thus negatively regulate the growth of A549 lung cancer cells.
Buckley
S
S
Developmental Biology, Children's Hospital Los Angeles Research Institute, Los Angeles, CA 90027, USA.
Shi
W
W
Driscoll
B
B
Ferrario
A
A
Anderson
K
K
Warburton
D
D
D000230:Adenocarcinoma / Q000188:drug therapy* / Q000503:physiopathology; D000256:Adenoviridae / Q000235:genetics; D000818:Animals; D055415:Bone Morphogenetic Protein 4; D019485:Bone Morphogenetic Proteins / Q000494:pharmacology*; D045744:Cell Line, Tumor / Q000166:cytology / Q000187:drug effects / Q000201:enzymology; D016922:Cellular Senescence / Q000187:drug effects*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D015536:Down-Regulation / Q000187:drug effects; D015870:Gene Expression / Q000187:drug effects; D005822:Genetic Vectors; D006801:Humans; D008175:Lung Neoplasms / Q000188:drug therapy* / Q000503:physiopathology; D051379:Mice; D008819:Mice, Nude; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D009368:Neoplasm Transplantation; D010641:Phenotype; D010766:Phosphorylation; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D051785:Smad Proteins; D051898:Smad1 Protein; D019098:Telomerase / Q000378:metabolism; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism; D023041:Xenograft Model Antitumor Assays; D001616:beta-Galactosidase / Q000235:genetics / Q000378:metabolism
C525809:BMP4 protein, human; C525810:Bmp4 protein, mouse; D055415:Bone Morphogenetic Protein 4; D019485:Bone Morphogenetic Proteins; D004268:DNA-Binding Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; C497399:SMAD1 protein, human; D051785:Smad Proteins; D051898:Smad1 Protein; C497401:Smad1 protein, mouse; D015534:Trans-Activators; D042461:Vascular Endothelial Growth Factor A; D020928:Mitogen-Activated Protein Kinases; D019098:Telomerase; D001616:beta-Galactosidase