Hematopoietic Differentiation of ES Cells from P230 Bcr/Abl Transgenic Mouse.

Chronic neutrophilic leukemia (CNL) is a distinct disease form with less aggressive phenotype mimicking chronic myelogenous leukemia (CML). The patients present lower white blood cell counts consisting principally of neutrophilia, more severe thrombocytosis, less severe anemia, and delayed or absent transformation to blastic crisis. CNL sometimes has the translocation (9; 22) results in the transcription of an e19/a2 type Bcr/Abl mRNA that codes for a 230-kD Bcr/Abl protein (P230). Recently, we generated the P230 Bcr/Abl-transgenic mice, whose disease phenotype is myeloproliferative disese (MPD) with thrombocytosis. To investigate the disease phenotype of p230 Bcr/Abl-expressing MPD, we derived embryonic stem (ES) cells from the P230 Bcr/Abl transgenic mouse and non-transgenic control mouse. We differentiated ES cells on OP9 stromal cells, which supportive for hematopoietic differentiation. After day 5, ES cells were differentiated into megkaryocytes with TPO, erythrocytes with EPO and myeloid cells without cytokines. At day 13, floating cells were analyzed with lineage specific markers of megakaryocyte (CD61), erythroid (TER119) and myeloid (CD11b) cells by FACS analysis. P230 Bcr/Abl ES cell had more tendency of myeloid differentiation than control ES cell. With methylcellulose colony assays, we found that P230 Bcr/Abl ES cell produced more colony forming units. Intriguingly, the number of myeloid colonies was significantly increased and that of erythroid colonies was slightly decreased with no significance. It is reported that P210 Bcr/Abl markedly suppressed erythroid colony development. These data suggested that P230 Bcr/Abl enhances myeloid development in hematopoiesis and that it suppresses erythropoiesis not as strongly as P210 Bcr/Abl.