目的 構(gòu)建腫瘤壞死因子相關(guān)凋亡誘導配體（TRAIL）基因修飾的臍帶間充質(zhì)干細胞（TRAIL-MSCs），并檢測其聯(lián)合地塞米松（DEX）對急性B淋巴細胞白血?。∟alm-6）細胞的影響。方法 通過慢病毒載體將SPD-TRAIL基因轉(zhuǎn)染UC-MSCs構(gòu)建TRAIL-MSCs，使其能夠表達十二聚體TRAIL蛋白（dTRAIL）。通過CCK-8法、流式細胞術(shù)、顯微鏡光鏡下觀察細胞形態(tài)及密度檢測UC-MSCs、TRAIL-MSCs、DEX（25 μmol/L）、DEX（25 μmol/L）＋UC-MSCs組和DEX（25 μmol/L）＋TRAIL-MSCs對Nalm-6細胞增殖、凋亡的影響；通過實時熒光定量PCR及Western blotting法檢測各組Nalm-6細胞表面DR4、DR5 mRNA和蛋白表達。結(jié)果 成功構(gòu)建了能夠穩(wěn)定表達dTRAIL蛋白的TRAIL-MSCs工作庫細胞。與對照組比較，UC-MSCs、TRAIL-MSCs顯著抑制Nalm-6細胞增殖（P<0.01），但抑制率均在30%以下，DEX抑制率約為43%，而DEX聯(lián)合TRAIL-MSCs抑制率達85%，與TRAIL-MSCs和DEX組比較差異顯著（P<0.01）。顯微鏡下觀察結(jié)果顯示，不同處理方式對腫瘤細胞Nalm-6均有一定的殺傷作用，其中以DEX與TRAIL-MSCs聯(lián)合用藥組的殺傷作用最明顯。TRAIL-MSCs可以促進Nalm-6細胞凋亡，凋亡率達10%，DEX組凋亡率達到15%，與對照組比較有顯著差異（P<0.05、0.01）；而DEX＋TRAIL-MSCs組凋亡率達36%，與DEX和TRAIL-MSCs組比較有顯著差異（P<0.01）。與對照組比較，TRAIL-MSCs組DR4、DR5 mRNA表達量顯著降低（P<0.01）；DEX可以促進DR4、DR5 mRNA表達，與對照組比較差異顯著（P<0.01）；DEX＋TRAIL-MSCs組較DEX組DR4、DR5 mRNA表達均顯著降低（P<0.01）；各組蛋白檢測結(jié)果與mRNA結(jié)果基本一致。結(jié)論 DEX可以顯著提高TRAIL-MSCs對Nalm-6細胞的殺傷作用，或?qū)⒊蔀橐环N頗具潛力的血液腫瘤治療新手段；其機制與DEX顯著提高DR4、DR5表達，增強Nalm-6細胞對TRAIL蛋白的敏感性相關(guān)。

Objective Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) gene modified umbilical cord mesenchymal stem cells (TRAIL-MSCs) were constructed, and the effect of TRAIL-MSCs combined with dexamethasone (DEX) on acute B lymphocytic leukemia (Nalm-6) cells was detected. Methods We transfected SPD-TRAIL gene into umbilical cord mesenchymalstem cells by lentiviral vector to enable them to express TRAIL protein. Then, the effects of DEX combined with TRAIL-MSCs on the proliferation and apoptosis of Nalm-6 were detected by CCK-8 and flow cytometry, respectively. The mRNA and protein levels of DR4 and DR5 on the surface of Nalm-6 cells treated with DEX and TRAIL-MSCs were further detected. Results Compared with control group, UC-MSCs and TRAIL-MSCs significantly inhibited the proliferation of Nalm-6 cells (P < 0.01), but the inhibition rate was less than 30%, the inhibition rate of DEX was about 43%, and the inhibition rate of DEX combined with TRAIL-MSCs was 85%, compared with TRAIL-MSCS and DEX groups, there was significant difference (P < 0.01). The results of microscope observation showed that different treatment methods had certain killing effect on Nalm-6 tumor cells, among which the combination of DEX and TRAIL-MSCs showed the most obvious killing effect. TRAIL-MSCs could promote the apoptosis of Nalm-6 cells, the apoptosis rate was 10%, and the apoptosis rate of DEX group was 15%, which was significantly different from that of control group (P < 0.05, 0.01). The apoptosis rate of DEX + TRAIL-MSCs group was 36%, which was significantly different from that of Dex and TRAIL-MSCs groups (P < 0.01). Compared with control group, the mRNA expression levels of DR4 and DR5 in TRAIL-MSCs group were significantly decreased (P < 0.01). DEX could promote the mRNA expression of DR4 and DR5, and the difference was significant compared with control group (P < 0.01). The mRNA expression of DR4 and DR5 in DEX +TRAIL-MSCs group was significantly lower than that in DEX group (P < 0.01). Protein detection results of each group were basically consistent with mRNA results. Conclusion DEX can significantly improve the efficacy of TRAIL gene modified umbilical cord mesenchymal stem cells in the treatment of acute Blymphocytic leukemia, which may become a potential new strategy for hematologic tumors. The mechanism was related to the significantly increased expression of DR4 and DR5 by DEX and enhanced sensitivity of NALM-6 cells to TRAIL protein.

R965

北京市科技計劃課題（Z211100002521006）；河北醫(yī)科大學第二醫(yī)院院基金（2h2201609）