目的 構(gòu)建腫瘤壞死因子相關(guān)凋亡誘導(dǎo)配體（TRAIL）基因修飾的臍帶間充質(zhì)干細(xì)胞（TRAIL-MSCs），并檢測其聯(lián)合地塞米松（DEX）對急性T淋巴細(xì)胞白血病細(xì)胞系（Jurkat）的影響。方法 通過慢病毒載體將SPD-TRAIL基因轉(zhuǎn)染臍帶間充質(zhì)干細(xì)胞（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(xì)胞術(shù)檢測UC-MSCs、TRAIL-MSCs、DEX （200 μmol/L）、DEX （200 μmol/L） ＋UC-MSCs和DEX （200 μmol/L） ＋TRAIL-MSCs對Jurkat細(xì)胞增殖、凋亡的影響；顯微鏡光鏡下觀察細(xì)胞形態(tài)及密度；通過實時熒光定量PCR及Westernblotting法檢測各組Jurkat細(xì)胞表面死亡受體DR4、DR5 mRNA和蛋白表達水平。結(jié)果 CCK-8結(jié)果顯示，各處理組均可以抑制Jurkat細(xì)胞的增殖，與對照組比較有顯著性差異（P<0.01）；同時，DEX可以提高TRAIL-MSCs （抑制率約20%）對Jurkat細(xì)胞的增殖抑制作用，抑制率提高至60%，與TRAIL-MSCs組比較差異顯著（P<0.01）。顯微鏡觀察結(jié)果發(fā)現(xiàn)，DEX與TRAILMSCs聯(lián)合組對腫瘤細(xì)胞Jurkat的殺傷作用最明顯；流式細(xì)胞術(shù)結(jié)果顯示，TRAIL-MSCs對Jurkat細(xì)胞有促進凋亡的作用，凋亡率達10%，單獨使用DEX后，凋亡率約20%，與對照組比較差異顯著（P<0.01）； DEX聯(lián)合TRAIL-MSCs作用于Jurkat細(xì)胞48 h后，細(xì)胞凋亡率為38%，較TRAIL-MSCs組顯著提高（P<0.01）。TRAIL-MSCs組DR4、DR5的mRNA、蛋白水平較對照組顯著降低（P<0.01），DEX組DR4、DR5的mRNA、蛋白水平較對照組顯著升高（P<0.01），DEX與TRAIL-MSCs聯(lián)合作用后，DR4、DR5的mRNA、蛋白水平較DEX組顯著降低（P<0.01）。結(jié)論 DEX可以提高腫瘤細(xì)胞Jurkat對TRAILMSCs的敏感性，增強TRAIL-MSCs對腫瘤細(xì)胞的殺傷作用，可能與提高DR4、DR5表達有關(guān)。

Objective Genetically modified mesenchymal stem cells (TRAIL-MSCs) expressing TRAIL were constructed and combined with dexamethasone (DEX) to detect the effect on acute T lymphoblastic leukemia cell line (Jurkat). Methods The proliferation inhibition, apoptosis, cell density and morphology of Jurkat cells induced by DEX (200 μmol/L) combined with TRAILMSCs were detected by CCK-8, flow cytometry and microscope observation. At the same time, qRT-PCR and Western blotting techniques were used to detect the expression of DR4 and DR5 in Jurkat cells at nucleic acid level and protein level. Results The results of CCK-8 showed that TRAIL-MSCs could inhibit the proliferation of tumor cells, with an inhibition rate of about 20%, which was significantly different from that of the control group (P<0.01). DEX could improve the inhibitory effect of TRAILMSCs on the proliferation of tumor cell Jurkat, and the inhibition rate was increased to 60%. Compared with TRAIL-MSCs group, the difference was significant (P<0.01). The results of microscopic observation showed that the killing effect of DEX combined with TRAIL-MSCs on tumor cell Jurkat was the most obvious. The results of apoptosis detected by flow cytometry showed that TRAIL-MSCs could promote the apoptosis of tumor cell Jurkat, but after the combination of DEX and TRAIL-MSCs, the apoptosis rate increased from 10% to 38%, which was significantly different from that of the control group and DEX group (P<0.01). The effects of different treatments on the nucleic acid level and protein level of DR4 and DR5 in Jurkat cells were detected by qPCR and WB respectively. The results showed that the expression of DR4 and DR5 in TRAIL-MSCs group was significantly lower than that in control group (P<0.01). DEX can promote the expression of DR4 and DR5, which is significantly different from that of the control group (P<0.01). After the treatment of DEX and TRAIL-MSCs, the expression of DR4 and DR5 was significantly lower than that of DEX group (P<0.01). Conclusion DEX can enhance the sensitivity of tumor cell Jurkat to TRAIL-MSCs and enhance the killing effect of TRAIL-MSCs on tumor cells, which may be related to the increase of DR4 and DR5 expression in tumor cells by DEX.

R965

北京市科技計劃課題（Z211100002521006）