MSI2通过下调circRNA_001214促进急性髓系白血病细胞HL60生长

Musashi-2（MSI2）是一种RNA结合蛋白质，对维持造血干细胞功能具有重要作用。研究表明，MSI2高表达能促进急性髓系白血病（acute myelocytic leukemia, AML）进展，但其作用机制尚不明确。本研究稳定沉默HL60细胞MSI2后，第1、2、3、4 d对照组的相对细胞生长率分别为1.931 ± 0.027、3.070 ± 0.073、4.017 ± 0.092和4.215 ± 0.246；敲减组分别为1.927 ± 0.035、2.564 ± 0.090、2.825 ± 0.097和3.223 ± 0.182，两组相比具有统计学差异，P<0.001；细胞凋亡明显增加(7.967% ± 0.698% vs 3.400% ± 0.322%., P<0.01)；G₀/G₁期细胞比例明显增高（67.430% ± 4.390% vs. 50.360% ± 2.160%, P<0.01）；NUMB蛋白明显上调，LEF1明显下降。环状RNA（circular RNA, circRNA）芯片筛选和荧光定量PCR验证显示，MSI2沉默组circRNA_001214表达水平是对照组3.48倍。这一结果也在NALM6细胞得到证实。进一步用生物信息学分析，显示circRNA_001214最可能与miR-1273a、miR-1273e和miR 5095结合，进而影响参与细胞凋亡相关基因（CYCS、AKT1、BAX、TNFRSF10A、TNFRSF10D）、Wnt信号基因（WNT4、WNT2B、WNT7B、 DKK2、SFRP1、CSNKE1和LEF1）以及参与细胞代谢相关基因（RPE, PGAM4, PGAM1, TAT, CBS、RPE、SUCLG2、PGAM4、PGAM1和 IDNK）。总而言之，MSI2可能通过干扰circRNA_001214生成，减少靶miRNA对凋亡、Wnt信号及细胞代谢相关基因表达的影响，促进细胞生长。

MSI2 Promotes the Proliferation of Acute Myelocytic Leukemia HL60 Cells by Down-regulating CircRNA_001214#br#

Musashi2 (MSI2) is a RNA-binding protein that plays an important role in maintaining the function of hematopoietic stem cells. Previous studies indicated that high expression of MSI2 accelerates progression of acute myelocytic leukemia (AML), while its mechanism was not clear. In this research, after MSI2 was stably knocked-down in HL60 cells, the percentage of cell proliferation in four days was 1.927 ± 0.035, 2.564 ± 0.090, 2.825 ± 0.097 and 3.223 ± 0.182, lower than 1.931 ± 0.027, 3.070 ± 0.073, 4.017 ± 0.092 and 4.215 ± 0.246 of the control group, P<0.001. The cellular apoptosis rate was increased (7.967% ± 0.698% vs. 3.400% ± 0.322%, P<0.01). Compared with the ratio of G0/G1 in the control group, the MSI2-knockdown group had higher ratio of G₀/G₁ cells (67.430% ± 4.390% vs. 50.360% ± 2.160%, P<0.01). After stable MSI2 knockdown, the NUMB protein increased while LEF1 decreased. CircRNA chip and quantitative RT-PCR assays demonstrated that the expression of circRNA_001214 was 3.48 times higher in the MSI2 knockdown group than in the control group, which was also validated in acute lymphocytic leukemia (ALL) NALM6 cells. The further bioinformatics analysis indicated that miR-1273a, miR-1273e and miR-5095 were the most probable binding sites of circRNA_001214. These miRNAs were involved in regulating apoptosis-related genes (CYCS, AKT1, BAX, TNFRSF10A, TNFRSF10D), Wnt signalling related genes (WNT4, WNT2B, WNT7B, DKK2, SFRP1, CSNKE1 and LEF1) and cell metabolism related genes (RPE, PGAM4, PGAM1, TAT, CBS, RPE, SUCLG2, PGAM4, PGAM1 and IDNK). Taken together, MSI2 reduces the influence of target miRNAs to cellular apoptosis, Wnt signaling and cell metabolism-related genes’ expression by reducing the production of circRNA_001214, thus promoting cell proliferation.