Analysis of granulocyte colony stimulating factor receptor isoforms, polymorphisms and mutations in normal haemopoietic cells and acute myeloid leukaemia blasts

Abstract

Deletion mutants of the intracytoplasmic domain of the granulocyte colony stimulating factor receptor (G-CSFR) have shown that it contains a membrane-proximal region which must be conserved to allow the receptor to transduce a mitotic signal, and a C-terminal region necessary for transduction of cell differentiation. Changes in the intracytoplasmic domain may result in the uncoupling of these two processes, as in acute leukaemia, and such alterations could occur either as isoforms or mutations. We have studied the transmembrane domain and intracytoplasmic tail of the G-CSFR in RNA from blood or bone marrow of 11 haematologically normal controls and 40 patients with acute myeloid leukaemia (AML). Two novel transcripts of the receptor were identified, both were minor components and are unlikely to be of major physiological significance. We could find no evidence for altered levels of expression of these transcripts in the AML patients. In addition, only one point mutation was detected in the 40 patients screened by RT-PCR-SSCP, a C-->A substitution at nucleotide 2088 which changes a threonine to asparagine in the transmembrane domain and is probably a polymorphism. These results suggest that abnormalities in the G-CSFR are uncommon in AML.

Csf3r mutations in mice confer a strong clonal HSC advantage via activation of Stat5

“…Whereas truncation mutations of CSF3R are present in 78% of cases of MDS/AML in patients with SCN (10), they are observed in only 1%-2% of de novo AML cases (10,30,31). These mutations are acquired and achieve clonal dominance in the human bone marrow microenvironment.…”

An activating mutation in the transmembrane domain of the granulocyte colony-stimulating factor receptor in patients with acute myeloid leukemia

“…In a study of the G-CSF receptor (G-CSFR) in 40 AML patients, we previously reported identifying a base change which would potentially cause a threonine to asparagine substitution at amino acid 617 in the TM domain (Bernard et al, 1996). It was not clear, however, whether this base change was a leukemiaspecific mutation or an infrequent polymorphism because no remission blood or bone marrow, constitutive DNA or family members were available for study.…”

“…The Thr617Asn base change was originally identified in an AML patient with FAB type M1 who had since died and had no living relatives (Bernard et al, 1996). Semi-quantitative PCR with a mismatch primer and HincII digestion showed that the mutant was 32% of total G-CSFR in peripheral blood from the first patient.…”

Increased granulocyte colony-stimulating factor responsiveness but normal resting granulopoiesis in mice carrying a targeted granulocyte colony-stimulating factor receptor mutation derived from a patient with severe congenital neutropenia.

“…However, these data do not exclude a role for G-CSFR mutations in the development of AML or MDS in patients with SCN. Of note, only 1 out of 58 patients with de novo AML and 0 of 29 patients with chronic myelogenous leukemia in blast crisis have been found to have a similar mutation, suggesting an unique association between SCN and G-CSFR mutations (26,27). It is possible that the combination of a G-CSFR mutation and the (currently unknown) genetic mutation responsible for SCN are required to substantially increase the risk of developing AML or MDS.…”

“…Point mutations that cluster in a very narrow range (nucleotides 2,384-2,429) of the G-CSFR gene occur in ‫ف‬ 25% of patients with SCN (10-13). Interestingly, these mutations appear to be unique to SCN as they have not yet been reported in other neutropenic syndromes (0 of 18 tested) or in healthy subjects (0 of 30 tested) (10,26,27). These mutations all result in the generation of a premature stop codon that leads to a truncation of the distal cytoplasmic region of the G-CSFR (10)(11)(12)(13).…”