title: Stem cell factor protects erythroid precursor cells from chemotherapeutic agents via up-regulation of BCL-2 family proteins.
abstract: Suppression of red blood cell production is a common complication of chemotherapy, causing anemia in a significant number of cancer patients. We have evaluated the sensitivity of human hematopoietic progenitors and erythroid precursor cells to chemotherapeutic drugs and found that probasophilic erythroblasts represent the stage of erythroid differentiation more vulnerable to the cytotoxic effects of myelosuppressive agents. Stem cell factor (SCF) supports proliferation and survival of early hematopoietic cells by binding to the c-kit receptor. In unilineage erythropoietic culture of CD34+ progenitors, short-term pretreatment of immature erythroid precursors with SCF results in protection from apoptosis induced by chemotherapeutic agents and restores normal proliferation and differentiation after removal of the cytotoxic stimulus. The levels of drug-induced caspase processing are significantly reduced in erythroblasts treated with SCF, indicating that activation of the c-kit receptor generates antiapoptotic signals acting before amplification of the caspase cascade. Accordingly, we found that SCF up-regulates Bcl-2 and Bcl-X L in erythroid precursors and that exogenous expression of these proteins protects erythroblasts from caspase activation and death induced by chemotherapeutic agents. These results suggest a possible mechanism for SCF-mediated protection of erythroid precursor cells from apoptosis and may contribute to devise new strategies for prevention and treatment of chemotherapy-induced anemia.
authors.affiliation: Department of Hematology and Oncology, Istituto Superiore de Sanità, Viale Regina Elena 299, 00161 Rome, Italy.
authors.forename: Ann
authors.initials: A
authors.lastname: Zeuner
authors.forename: Francesca
authors.initials: F
authors.lastname: Pedini
authors.forename: Michele
authors.initials: M
authors.lastname: Signore
authors.forename: Ugo
authors.initials: U
authors.lastname: Testa
authors.forename: Elvira
authors.initials: E
authors.lastname: Pelosi
authors.forename: Cesare
authors.initials: C
authors.lastname: Peschle
authors.forename: Ruggero
authors.initials: R
authors.lastname: De Maria
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D020169:Caspases / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects; D004336:Drug Antagonism; D015672:Erythroid Precursor Cells / Q000166:cytology / Q000187:drug effects*; D006412:Hematopoietic Stem Cells / Q000166:cytology / Q000187:drug effects; D006801:Humans; D008297:Male; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000032:analysis / Q000096:biosynthesis*; D019089:Stem Cell Factor / Q000494:pharmacology*; D015854:Up-Regulation / Q000187:drug effects; D051020:bcl-X Protein
chemical_list: D000970:Antineoplastic Agents; C494811:BCL2L1 protein, human; D019253:Proto-Oncogene Proteins c-bcl-2; D019089:Stem Cell Factor; D051020:bcl-X Protein; D020169:Caspases