Pim-1 induced polyploidy but did not affect megakaryocytic differentiation of K562 cells and CD34+ cells from cord blood.
In a previous study, we determined the gene expression profile of both megakaryocytic and non-megakaryocytic lineage cells via serial analysis of gene expression and microarray methods, and demonstrated that Pim-1 was expressed more abundantly in megakaryocytic lineage cells. In this study, we knocked down Pim-1 in K562 cells, as well as in CD34+ cells from cord blood, via RNA interference, in order to analyze the effects of Pim-1 expression on the megakaryocytic differentiation of these cells. We then additionally overexpressed the Pim-1 genes in K562 cells, and conducted a comparison of these effects with those of RNAi cells on the course of megakaryocytic differentiation. The results of this study revealed that Pim-1 knockdown exerted no effects on commitment or differentiation toward megakaryocytic lineage, as evidenced by the detected CD41+ or CD61+ cells, or on the number of megakaryocytic colony forming units. However, Pim-1 knockdown was found to elicit a reduction in CD41+ cells with >4n DNA content, and a concomitant increase in the fraction of cells achieving a ploidy of >4n in the Pim-1 overexpressing population of K562 cells. Collectively, the findings of these studies indicate that the expression of Pim-1 expression is both necessary and sufficient for polyploidization, but is not critical to cytoplasmic differentiation on megakaryopoiesis.
Jung
Yun-Jae
YJ
Department of Microbiology, Gachun Medical School, Inchon, Korea.
Chae
Hee-Chung
HC
Seoh
Ju-Young
JY
Ryu
Kyung-Ha
KH
Park
Hae-Kyung
HK
Kim
Young-Ju
YJ
Woo
So-Youn
SY
D002454:Cell Differentiation / Q000187:drug effects; D002478:Cells, Cultured / Q000166:cytology / Q000187:drug effects; D003114:Colony-Forming Units Assay; D005312:Fetal Blood / Q000166:cytology; D006412:Hematopoietic Stem Cells / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D007231:Infant, Newborn; D020014:K562 Cells / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D008533:Megakaryocytes / Q000166:cytology* / Q000187:drug effects; D011123:Polyploidy; D051573:Proto-Oncogene Proteins c-pim-1 / Q000235:genetics / Q000502:physiology*; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000494:pharmacology; D011993:Recombinant Fusion Proteins / Q000502:physiology; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D034061:Thrombopoiesis / Q000187:drug effects / Q000235:genetics / Q000502:physiology*
D034741:RNA, Small Interfering; D011993:Recombinant Fusion Proteins; C496634:PIM1 protein, human; D051573:Proto-Oncogene Proteins c-pim-1; D013755:Tetradecanoylphorbol Acetate