Abstract 5010: Microarray analysis of gene expression profiling of essential thromocythemia (ET) and post-ET MF (myelofibrosis) derived megakaryocytic cells

Abstract Patients with ET eventually transform into Post- ET MF in most cases after several years. The underlying mechanism of the transformation is still unknown. ET and Post-ET MF is characterized by abnormal megakaryocytic proliferation. Therefore we have performed microarray analysis of gene expression profiles to compare megakaryocytes derived from patients with Post-ET MF to ET. CD 34+ cells were obtained from peripheral blood, then cultured with Serum-Free Medium of stem cell factor (100 ng/mL) and thrombopoietin (TPO 100 ng/mL), and added murine bone marrow stromal cell line OP9 as feeder layer. Megakaryocytes were then obtained by MACS selection of CD 61+ cells after 10 days culture. Then oligonucleotide microarray analysis was performed by PhalanxBio Inc. (Palo, Alto, Ca). Gene expression profiling was achieved by using the comparative cycle threshold (CT) method of relative quantification (the calibration samples were MK pools from 10 ET patients with GAPDH used as internal controls). SLR (Signal log ratio) was then calculated for comparative analysis of 2 patients with post-ET MF to a pool of ET patients. The results of post-ET MF compared with ET were as follows: 1) with analysis of 4544 genes, SLR <−1 were 6.58 %, and 10.12 % were >1, 2) in apoptosis genes, over expressed genes were IGF-1R, CFLAR, NFKBA,(GLR between 1-1.5) down-regulated genes were BAX, LGALSI, PPPIR 15A, CASP3 (GLR between -0.5 to -0.1), 3) in cell cycle controlling genes, over expressed were IL8, INSIG1, IGF-1R, BCL3(GLR between 1 to 1.5), down-regulated were PPPIR15A (GLR = -0.7). 4) in megakaryocyte-important development genes, growth factor genes including PDGF A, C were up-regulated (GLR=1.8), and VEG B was down-regulated (GLR = -1. 4):; growth factor receptor genes including IL1R 1and 2, CXCR4, IL8, PF4 were up-regulated (GLR between 1-2), IL3RA, KIT were down-regulated (GLR between -1.6 to -3); cell cycle regulator genes including CCND1, 3, RASGRP3 were up-regulated (GLR between 1 to 2.5), CDK4 was down-regulated (GLR = -1); transcription regulators including CEBPE, CEBPG were up-regulated (GLR-1.5); all Signal transducers including all STAT 1-5, MAK14 were up-regulated (GLR between 1.5 to 2.4). There are 20 up-regulated genes and 20 down-regulated genes which need further analysis for their function. These preliminary analyses of MK genes comparison between Post ET-MF and ET suggest that many anti-apoptosis, cell cycle regulator genes, growth factor genes, growth factor receptor genes and all of the signal transducer genes for the MK development genes were up-regulated while many of the pro-apoptosis genes were down-regulated. Further work to dissect the genes using the microarray analysis for the mechanism for the transformation of ET into ET-MF will be important for understanding this disease. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5010. doi:10.1158/1538-7445.AM2011-5010