All-trans-retinoic acid effects the growth, differentiation and apoptosis of normal human myeloid progenitors derived from purified CD34+ bone marrow cells.
We have previously shown that all-trans retinoic acid (ATRA) increases the number of CFU-GM colonies grown from unseparated human bone marrow cells with crude sources of colony stimulating factors. In this study, we further characterized the effect of ATRA on the growth of CFU-GM stimulated by individual cytokines from multiple samples of CD34+ enriched or purified human bone marrow cells. The number of IL-3- or GM-CSF-induced CFU-GM with 3 x 10(-7) M ATRA was 3.25+/-1.13, and 2.17+/-0.8-fold greater respectively, compared to controls without ATRA, while G-CSF had no effect and the ratio of colony-induced with or without ATRA was 1.06+/-0.17 (P = 0.00012). No colonies grew with ATRA + IL-6 or ATRA without a cytokine. Maximum enhancing effect on IL-3-induced CFU-GM occurred when ATRA was added on day 2, gradually diminished when delaying ATRA, and in cultures of day 9 or older adding ATRA had no effect. In 14 days liquid cultures of purified CD34+ cells with IL-3, ATRA increased the number of myeloid differentiated cells to 91-95%, compared to 37-70% with IL-3 alone. In addition, the number of apoptotic cells using the annexin V method increased after 14 days from 5.1% with IL-3 to 17.1% with IL-3 + ATRA and by the TUNEL in situ method from 10-26% to 60-95%, respectively. This study demonstrates that ATRA consistently enhances the growth of myeloid progenitors from CD34+ cells. This effect is dependent on the stimulating cytokine, suggesting the myeloid cells responding to ATRA are the less mature CFU-GMs that are targets of IL-3 and GM-CSF and not the G-CSF-responding mature progenitors. The growth stimulation by ATRA and IL-3 is also associated with granulocyte differentiation and increased apoptosis. These studies further suggest a potential role of pharmacological doses of ATRA on the development of normal human hematopoietic cells.
Douer
D
D
Department of Medicine, University of Southern California/Norris Comprehensive Cancer Center, Los Angeles 90033, USA.
Ramezani
L
L
Parker
J
J
Levine
A M
AM
D018952:Antigens, CD34; D017209:Apoptosis / Q000187:drug effects*; D001854:Bone Marrow Cells / Q000166:cytology*; D002454:Cell Differentiation / Q000187:drug effects*; D002455:Cell Division / Q000187:drug effects; D003114:Colony-Forming Units Assay; D016179:Granulocyte Colony-Stimulating Factor / Q000494:pharmacology; D006412:Hematopoietic Stem Cells / Q000166:cytology / Q000187:drug effects* / Q000502:physiology; D006801:Humans; D007377:Interleukin-3 / Q000494:pharmacology; D013997:Time Factors
D018952:Antigens, CD34; D007377:Interleukin-3; D016179:Granulocyte Colony-Stimulating Factor