Forced expression of Id3 prevents growth suppression and cell death induced by DMH2.

<p>H1299 cells were stably transfected with Id1 and Id3 expression vectors or the insertless vector. (<b>A–B</b>) Western blot analysis showing increased expression of (<b>A</b>) Id1 or (<b>B</b>) Id3 in the transfected cell line. (<b>C–D</b>) H1299/Id1 and H1299/Id3 cells were treated with 1 µM DMSO or 1 µM DMH2 for 7 days and the percent alive and dead cells determined. (<b>C</b>) DMH2 caused growth suppression of vector control and H1299/Id1 cells but not H1299/Id3 cells. (<b>D</b>) DMH2 induced cell death in the vector control cells (H/con) but not in the H1299/Id3 cells (H/Id3). The data represents the mean of at least 3 experiments reported as the percent of control treated cells. (<b>E</b>) DMH2 deceases cell growth of immortalized normal human bronchial epithelial cells (HBEC) but not human aortic endothelial cells (HAEC). Cell lines growing in SFM were treated with 1 µM DMSO or 1 µM DMH2 for 7 day and cell counts performed. Data represents the mean of at least 3 experiments reported as the percent of control treated cells. (<b>F</b>) Western blot analysis showing higher expression of pSmad 1/5 and Id1 in HBEC compared to HAEC. 1 µM of DMH2 for 48 hours decreased expression of pSmad 1/5 and ID1 in HBEC but not HAEC.