title: Activated H-Ras regulates hematopoietic cell survival by modulating Survivin.
abstract: Survivin expression and Ras activation are regulated by hematopoietic growth factors. We investigated whether activated Ras could circumvent growth factor-regulated Survivin expression and if a Ras/Survivin axis mediates growth factor independent survival and proliferation in hematopoietic cells. Survivin expression is up-regulated by IL-3 in Ba/F3 and CD34+ cells and inhibited by the Ras inhibitor, farnesylthiosalicylic acid. Over-expression of constitutively activated H-Ras (CA-Ras) in Ba/F3 cells blocked down-modulation of Survivin expression, G0/G1 arrest, and apoptosis induced by IL-3 withdrawal, while dominant-negative (DN) H-Ras down-regulated Survivin. Survivin disruption by DN T34A Survivin blocked CA-Ras-induced IL-3-independent cell survival and proliferation; however, it did not affect CA-Ras-mediated enhancement of S-phase, indicating that the anti-apoptotic activity of CA-Ras is Survivin dependent while its S-phase enhancing effect is not. These results indicate that CA-Ras modulates Survivin expression independent of hematopoietic growth factors and that a CA-Ras/Survivin axis regulates survival and proliferation of transformed hematopoietic cells.
authors.affiliation: Department of Microbiology and Immunology, Walther Oncology Center, Indiana University School of Medicine, Walther Cancer Institute, Indianapolis, IN 46202, USA.
authors.forename: Seiji
authors.initials: S
authors.lastname: Fukuda
authors.forename: Louis M
authors.initials: LM
authors.lastname: Pelus
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology; D002453:Cell Cycle / Q000187:drug effects / Q000502:physiology; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects / Q000502:physiology; D004789:Enzyme Activation / Q000187:drug effects; D005204:Farnesol / Q000031:analogs & derivatives* / Q000494:pharmacology; D006412:Hematopoietic Stem Cells / Q000166:cytology* / Q000187:drug effects / Q000502:physiology*; D051034:Inhibitor of Apoptosis Proteins; D007377:Interleukin-3 / Q000494:pharmacology*; D051379:Mice; D008869:Microtubule-Associated Proteins / Q000378:metabolism*; D009363:Neoplasm Proteins; D000077022:Survivin; D018631:ras Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism*
chemical_list: C107489:BIRC5 protein, human; D051034:Inhibitor of Apoptosis Proteins; D007377:Interleukin-3; D008869:Microtubule-Associated Proteins; D009363:Neoplasm Proteins; D000077022:Survivin; C112353:farnesylthioacetic acid; D005204:Farnesol; D018631:ras Proteins