|
Journal of Clinical Oncology, 2006 ASCO Annual Meeting Proceedings (Post-Meeting Edition).
Vol 24, No 18S (June 20 Supplement), 2006: 6555
© 2006 American Society of Clinical Oncology
Similarities and differences in aging and in malignant transformation of human hematopoietic stem cells
H. Lannert,
T. Able,
T. Franz,
R. Hofmann,
A. Lenze,
K. Horsch,
V. Eckstein,
R. Saffrich and
A. D. Ho
Medical Clinic of the University Heidelberg, Heidelberg, Germany; EMBL, Heidelberg, Germany; Medical Clinic, Ludwigshafen, Germany
6555
Background: The tracking of stem cell aging, differentiation and deterioration by gene expression profiling and proteome analysis allows the comparison of different stages. The overall aim of a proteomic study is characterization of the complex network of cell regulation. We focused our investigations on different subsets of highly enriched CD34+ stem cells from different human origins: fetal liver, cord blood, bone marrow (BM), and mobilized stem cells from peripheral blood (PBSC), as well as CD34+ leukemia cells, thus e.g. to identify pathways and new targets for leukemia therapy. Methods: Mononuclear cells were isolated by a standard Ficoll separation method from the different blood sources. An Auto-MACS (Miltenyi) and FACS Vantage SE cell sorter (Becton Dickinson) was used to highly enrich (>99%) CD34+ cells fractions. Sample preparation: Total RNA was isolated from sorted 1 x 10e6 cells by standard methods using RNA isolation kit (Qiagen). For gene expression analysis topic-defined PIQOR stem cell microarrays (936 genes) were performed. Proteomics started with the determination of protein concentrations, 2D-gel-electrophoresis were described in Proteome Works System (BioRad). Sypro ruby and/or coomasie stained gels were used for protein identification by Q-TOF analyses. The subcellular localization of the identified proteins were performed by fluorescence and confocal microscopy of all cell fractions. Results: 1. The microarray gene expression correlation shows many similarities between human healthy stem cells of different sources and ages, otherwise many differences: 125 upregulated genes (kinases: PAK1, ATM1, CDKN2A) and 32 downregulated genes (EBCTF, RAMP1) in malignant cells compared to healthy stem cells. 2. Proteomics analyses of the different cell fractions show a large overlap of the most dominant protein spots, >200 spots were identified by Q-TOF. For example stathmin (oncoprotein Op18) is expressed at very high levels in leukemia cells and in PBSCs but not in BM cells, additionally demonstrated by fluorescence microscopy. Conclusions: Combining genomics and proteomics assays, pathways e.g. Op18 for proliferation and migration of healthy (mobilized) CD34+ cells from bone marrow and malignant leukemia cells could be identified.
No significant financial relationships to disclose.
Abstract presentation from the 2006 ASCO Annual Meeting
|
