12th Congress of the European Hematology ... - Haematologica

12 th Congress of the European Hematology Association
forming ability were evaluated. Results. The expression and localization
of β-catenin in CD34 + HSC/HPCs treated with GI9 was observed with
confocal microscopy. After the treatment for 24 hrs, expression of βcatenin
in NC cells was scarcely detected except for the membranebounded
form, which constitutes the cytoskeleton. On the other hand,
in GI9-treated cells, β-catenin accumulated in their nucleus in a dose
dependent manner. These results suggested that GI9-treatment activates
intrinsic β-catenin in human HSC/HPCs. After 7 days culture in a serumfree
medium containing with cytokines, total viable cells and CD34 +
cells were expanded 31.6±4.6 and 17.9±3.8 fold in NC cells, respectively
(n=3). However, GI9-treatment could not maintain a proportion of
CD34 + cells compared with NC and significantly caused the growth
inhibition in a dose dependent manner. About 80% of expanded cells
expressed myeloid marker, CD33 in our culture system, however, GI9treatment
perturbed myeloid differentiation of CD34+ HSC/HPCs but
induced the differentiation toward to megakaryocyte and erythroid lineages.
Furthermore, in methylcellulose assay, although expanded cells
with GI9-treatment generated all types of progenitors, GI9-treatment
was inferior significantly in terms of expansion rate of myeloid progenitor,
CFU-GM and superior in formation of erythroid progenitor,
BFU/CFU-E compared with NC (No. of CFU-GM/1000 cells 151±65.8
vs. 284±17.0, No. of BFU/CFU-E/1000 cells 132±18.5 vs. 32.7.±7.0,
respectively) (p