title: C-fms expression correlates with monocytic differentiation in PML-RAR alpha+ acute promyelocytic leukemia.
abstract: We have investigated the expression of the M-CSF receptor (c-fms) in 16 freshly isolated acute promyelocytic leukemias (APL) expressing the PML/RAR alpha fusion protein. In parallel, we evaluated the capacity of these cells to differentiate along the granulocytic and monocytic pathways. c-fms was constitutively and constantly expressed in all cases sensitive in vivo to all-trans retinoic acid (ATRA) and its expression was further potentiated following in vitro induction with ATRA. Furthermore, gel-shift analysis of APL cells showed elevated levels of PU.1 binding activity to the M-CSF receptor promoter, particularly after ATRA stimulation. Interestingly, the rise of PU.1 binding activity as well as of PU.1 levels after ATRA treatment was significantly higher in APL patients exhibiting monocytic maturation, as compared to those that did not undergo monocytic differentiation. A variable proportion of ATRA-induced APL cells exhibited monocyte-like morphology and immunophenotype: the proportion of monocytic cells was consistently increased by combined treatment with ATRA and diverse hematopoietic growth factors cocktails, which always comprised M-CSF. Monocytic cells originating from in vitro ATRA-induced maturation of APL cells derive from the leukemic clone as suggested by two lines of evidence: (1) monocytic cells harbor the 15;17 translocation; (2) monocytic cells possess Auer bodies. The c-fms(bright) leukemic blasts preferentially showed the capacity for monocytic differentiation as compared to the c-fms(dim/-) subset: indeed, enforced expression of c-fms into NB4, a PML/RAR alpha+ cell line, favored the onset of monocytic maturation. Finally, low c-fms expression was observed in an APL relapsing patient resistant to ATRA, as well as in an APL case with t(11;17), PLZF/RAR alpha+. These observations indicate that PML/RAR alpha+ APL blasts are bipotent for differentiation through both neutrophilic and monocytic lineages, whereby monocytic differentiation is linked to c-fms expression and stimulation.
authors.affiliation: Department of Hematology and Oncology, Istituto Superiore di Sanità, Rome, Italy.
authors.forename: R
authors.initials: R
authors.lastname: Riccioni
authors.forename: E
authors.initials: E
authors.lastname: Saulle
authors.forename: S
authors.initials: S
authors.lastname: Militi
authors.forename: N M
authors.initials: NM
authors.lastname: Sposi
authors.forename: M
authors.initials: M
authors.lastname: Gualtiero
authors.forename: N
authors.initials: N
authors.lastname: Mauro
authors.forename: M
authors.initials: M
authors.lastname: Mancini
authors.forename: D
authors.initials: D
authors.lastname: Diverio
authors.forename: F
authors.initials: F
authors.lastname: Lo Coco
authors.forename: C
authors.initials: C
authors.lastname: Peschle
authors.forename: U
authors.initials: U
authors.lastname: Testa
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015703:Antigens, CD / Q000276:immunology / Q000378:metabolism; D000970:Antineoplastic Agents / Q000627:therapeutic use; D015153:Blotting, Western; D002454:Cell Differentiation; D017931:DNA Primers / Q000737:chemistry; D024202:Electrophoretic Mobility Shift Assay; D005260:Female; D005434:Flow Cytometry; D015973:Gene Expression Regulation, Leukemic; D006801:Humans; D016130:Immunophenotyping; D017404:In Situ Hybridization, Fluorescence; D015473:Leukemia, Promyelocytic, Acute / Q000188:drug therapy / Q000378:metabolism* / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D009000:Monocytes / Q000473:pathology; D009363:Neoplasm Proteins / Q000378:metabolism*; D015514:Oncogene Proteins, Fusion / Q000378:metabolism*; D010641:Phenotype; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics; D012334:RNA, Neoplasm; D016186:Receptor, Macrophage Colony-Stimulating Factor / Q000378:metabolism*; D016184:Receptors, Colony-Stimulating Factor / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015534:Trans-Activators / Q000378:metabolism; D014162:Transfection; D014212:Tretinoin / Q000627:therapeutic use; D014407:Tumor Cells, Cultured; D000099232:Proto-Oncogene Protein Spi-1
chemical_list: D015703:Antigens, CD; D000970:Antineoplastic Agents; D017931:DNA Primers; D009363:Neoplasm Proteins; D015514:Oncogene Proteins, Fusion; D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger; D012334:RNA, Neoplasm; D016186:Receptor, Macrophage Colony-Stimulating Factor; D016184:Receptors, Colony-Stimulating Factor; D015534:Trans-Activators; D014212:Tretinoin; D000099232:Proto-Oncogene Protein Spi-1; C093476:promyelocytic leukemia-retinoic acid receptor alpha fusion oncoprotein