Role of Chk1 in the differentiation program of hematopoietic stem cells.
Hematopoietic stem cells (HSC) isolated from umbilical cord blood (UCB) were treated with ionizing radiation (IR) and sensitivity and IR induced checkpoints activation were investigated. No difference in the sensitivity and in the activation of DNA damage pathways was observed between CD133+ HSC and cells derived from them after ex vivo expansion. Chk1 protein was very low in freshly isolated CD133+ cells, and undetectable in ex vivo expanded UCB CD133+ cells. Chk1 was expressed only on day 3 of the ex vivo expansion. This pattern of Chk1 expression was corroborated in CD133+ cells isolated from peripheral blood apheresis collected from an healthy donor. Treatment with a specific Chk1 inhibitor resulted in a strong reduction in the percentage of myeloid precursors (CD33+) and an increase in the percentage of lymphoid precursors (CD38+) compared to untreated cells, suggesting a possible role for Chk1 in the differentiation program of UCB CD133+ HSC.
Laboratory of Molecular Pharmacology, Department of Oncology, Istituto di Ricerche Farmacologiche Mario Negri, via La Masa 19, 20156, Milan, Italy. laura.carrassa@marionegri.it
Laura
L
Carrassa
Elisa
E
Montelatici
Lorenza
L
Lazzari
Stefano
S
Zangrossi
Matteo
M
Simone
Massimo
M
Broggini
Giovanna
G
Damia
D000071916:AC133 Antigen; D015703:Antigens, CD / Q000378:metabolism; D015214:Antigens, Differentiation, Myelomonocytic / Q000378:metabolism; D016923:Cell Death / Q000187:drug effects / Q000528:radiation effects; D002454:Cell Differentiation / Q000187:drug effects / Q000528:radiation effects; D049109:Cell Proliferation / Q000187:drug effects / Q000528:radiation effects; D002469:Cell Separation; D000071877:Checkpoint Kinase 1; D004249:DNA Damage; D005312:Fetal Blood / Q000166:cytology; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects / Q000528:radiation effects; D006023:Glycoproteins / Q000378:metabolism; D006412:Hematopoietic Stem Cells / Q000166:cytology* / Q000187:drug effects / Q000201:enzymology* / Q000528:radiation effects; D006801:Humans; D007231:Infant, Newborn; D007700:Kinetics; D010455:Peptides / Q000378:metabolism; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011839:Radiation, Ionizing; D063268:Sialic Acid Binding Ig-like Lectin 3
D000071916:AC133 Antigen; D015703:Antigens, CD; D015214:Antigens, Differentiation, Myelomonocytic; C571163:CD33 protein, human; D006023:Glycoproteins; C000606023:PROM1 protein, human; D010455:Peptides; D047428:Protein Kinase Inhibitors; D012333:RNA, Messenger; D063268:Sialic Acid Binding Ig-like Lectin 3; D011494:Protein Kinases; C000605867:CHEK1 protein, human; D000071877:Checkpoint Kinase 1