Effect of TBLR1-RARα Fusion Gene on Erythroid Differentiation of K562 Cells / 中国实验血液学杂志

<p><b>OBJECTIVE</b>To explore the effects of TBLR1-RARα on the differentiation induction of leukemia cell line K562 cells into erythroid lineage and to investigate its related mechanisms.</p><p><b>METHODS</b>Tet-Off inducible system was used to construct the conditional expression vector of TBLR1-RARα fusion gene by cloning the TBLR1-RARα fragment into lentivirus vector pLVX-Tight-Puro, the expression of TBLR1-RARα fusion gene was induced by doxycycline (Dox). Then, K562 cells were transfected with lentivirus pLVX-Tight-Puro-TBLR1-RARα-flag, and the expression of fusion proteins was verified by Western blot. After treatment of K562 with all-trans retinoid acid (ATRA), real time RT-PCR was performed to test the expression of erythroid differentiation-related CD71 and α, ε, γ-globins gene. Flow cytometry was used also to analyze the expression of erythroid differentiation markers CD71 and CD235a. Benzidine staining was used to detect the production of hemoglobin in K562 cells.</p><p><b>RESULTS</b>qRT-RCR showed that ATRA could increase the expression level of CD71 and α, ε, γ-globin genes when TBLR1-RARα was expressed. After treatment of ATRA, the proportion of CD71(+) cells detected by the flow cytometry also increased. Benzidine staining showed that ATRA could induce hemoglobin production in K562 cells with TBLR1-RARα fusion gene expression.</p><p><b>CONCLUSION</b>The expression of TBLR1-RARα fusion gene contribute to ATRA-inducing differentiation of K562 cells into erythroid lineage.</p>

Silence potentiates chemosensitivity of K562 cells to SAHA / 中国实验血液学杂志

Ribosomal protein S27a (RPS27a) can perform extra-ribosomal functions besides imparting a role in ribosome biogenesis and post-translational modifications of proteins. The RPS27a gene has been reported to be over-expressed in breast fibroadenomas, colorectal and renal cancers, advanced-phase chronic myeloid leukemia (CML) and acute leukemia (AL) patients. This study was purposed to explore the function of RPS27a in CML-erythroleukemia cell line K562 cells. RPS27a was silenced by short hairpin RNA (shRNA) in K562 cells. Furthermore, the proliferation changes of K562 cells was detected by MTT method after silencing the RPS27a with suberoylanilide hydroxamic acid (SAHA), then the IC50 of K562-sh1/sh2 and K562-scr cells to SAHA was measured. The results indicated that compared with K562-scr cells, the IC50 of K562-sh1/sh2 to SAHA at 24 h and 48 h decreased (P < 0.01); RPS27a silence significantly increased the percentage of apoptotic K562-sh1/sh2 cells after incubation with 1 µmol/L, 2 µmol/L and 5 µmol/L SAHA for 24 h and 48 h as compared with that of K562-scr cells (P < 0.01). K562-sh1, K562-sh2 and K562-scr cells after incubation with or without 2 µmol/L SAHA for 48 h presented apoptosis features: i. e. chromatin condensation, nucleic fragmentation and apoptotic body formation. It is concluded that RPS27a can inhibit the apoptosis of K562 cells and RPS27a silence can potentiate sensitivity of K562 cells to SAHA.