Drm/Gremlin transcriptionally activates p21(Cip1) via a novel mechanism and inhibits neoplastic transformation.
Drm/Gremlin, a member of the Dan family of BMP antagonists, is known to function in early embryonic development, but is also expressed in a tissue-specific fashion in adults and is significantly downregulated in transformed cells. In this report, we demonstrate that overexpression of Drm in the tumor-derived cell lines Daoy (primitive neuroectodermal) and Saos-2 (osteoblastic), either under ecdysone-inducible or constitutive promoters, significantly inhibits tumorigenesis. Furthermore, Drm overexpression in these cells increases the level of p21(Cip1) protein and reduces the level of phosphorylated p42/44 MAP kinase. Finally, our data indicate that Drm can induce p21(Cip1) transcriptionally via a novel pathway that is independent of p53 and the p38 and p42/44 MAP kinases. These results provide evidence that Drm can function as a novel transformation suppressor and suggest that this may occur through its affect on the levels of p21(Cip1) and phosphorylated p42/44 MAPK.
Chen
Bo
B
Basic Research Laboratory, National Cancer Institute at Frederick, Bldg. 469, Rm. 102, Frederick, MD 21702-1201, USA.
Athanasiou
Meropi
M
Gu
Qiuping
Q
Blair
Donald G
DG
D002471:Cell Transformation, Neoplastic; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D010766:Phosphorylation; D011506:Proteins / Q000502:physiology*; D014158:Transcription, Genetic; D014407:Tumor Cells, Cultured; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism
C493956:CDKN1A protein, human; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins; C486399:GREM1 protein, human; D036341:Intercellular Signaling Peptides and Proteins; D011506:Proteins; D016159:Tumor Suppressor Protein p53; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases