Proteome Analysis of the Proteins Associated with All-Trans Retinoic Acid Resistance in Acute Promyelocytic Leukemia Cells

Although 90% patients with untreated acute promyelocytic leukemia(APL) obtain complete remission because of the usage of all-trans retinoic acid(ATRA), patients with ATRA-resistance are increased gradually. ATRA-resistance has become one of the main causes which affect the long-term therapeutic efficacy of APL. The mechanisms of ATRA-resistance are complex, which probably involve the metabolism of ATRA, abnormal expression of cellular retinoic acid binding protein(CRABP) and P-glycoprotein(P-gp), mutation of RARα and aberration translocation of APL. However, in these previous researches, it was one or a few proteins but not the entirety proteins that were emphasized on the mechanisms of ATRA-resistance. Comparative proteomics can analyze the entire protein expression in cells in whole and has the superiority in screening the drug-resistance proteins differentially expressed. In order to investigate the mechanisms of ATRA-resistance in APL in whole, we compared and analyzed the protein expression profiles between MR2 cells(APL cell line with ATRA-resistance) and NB4 cells(APL cell line with ATRA-sensitiveness) by comparative proteomics. After the total proteins of MR2 cells and NB4 cells were extracted respectively, they were separated by two-dimensional electrophoresis(2-DE). The differences in proteome profile between MR2 cells and NB4 cells analyzed by ImageMaster^™ 2D Platinum software. The average protein spots in 2-DE maps of MR2 and NB4 cells were 1160±51 and 1068±33 respectively. 8 protein spots were selected to be identified by Matrix-assisted laser desorption/ionization time of flight-mass spectrometry (MALDI-TOF-MS), in which the quantity of the protein differentially expressed was more than two times(≥2 or ≤0.5) between MR2 and NB4 cells’ 2-DE map. They were all successfully identified and their definite information was obtained. Among them, 6 proteins were probably involved in the mechanisms of ATRA-resistance in APL and they were Cofilin-1, Elongation factor 1-beta (EF-1β), Tropomyosin isoform(TM), High mobility group protein B1(HMGB1), Ran-specific GTPase-activating protein (RanGAP1) and Galectin-1. Moreover, so far there was no related report on the roles of HMGB1, RanGAP1 and Galectin-1 in the mechanisms of ATRA-resistance in APL. These differential proteins identified provide the new clues for us to further elucidate the mechanisms of ATRA-resistance from multiple factor.