肿瘤细胞对不同分化阶段树突状细胞脂含量和蛋白质二级结构的影响

Effects of tumor cells on lipid contents and protein secondary structures of dendritic cells at different differentiation stages

目的:利用傅里叶变换红外光谱(Fourier transformed infrared spectrum,FT-IR)技术探讨肿瘤细胞共培养对不同分化阶段树突状细胞(dendritic cells,DCs)的脂含量和蛋白质二级结构的影响,为深入理解肿瘤的免疫逃逸机制寻找线索。方法:免疫磁珠法分离人CD14+单核细胞,以经典方法将其诱导为未成熟DCs(immature DCs,imDCs)和成熟DCs(mature DCs,mDCs),分别将imDCs和mDCs与肝癌细胞株BEL7402、红白血病细胞株K562以及人脐静脉内皮细胞(human umbilical vein endothelialcells,HUVECs)共培养48 h,正常培养的DCs作为对照。采用FT-IR技术研究不同肿瘤细胞对不同分化阶段DCs的脂含量和蛋白质二级结构的影响。结果:与正常培养的DCs相比,与肿瘤细胞BEL7402和K562共培养后imDCs和mDCs的膜磷脂成分减少(2.718±0.296,3.124±0.361vs4.855±0.324,P<0.05;2.964±0.136,3.522±0.173vs4.217±0.206,P<0.05),而总的脂含量增加(3.768±0.185,3.591±0.197vs2.487±0.212,P<0.05;4.288±0.156,4.155±0.167vs3.233±0.206,P<0.05);蛋白质α-螺旋含量减少(1.863±0.192,1.754±0.169vs2.364±0.188,P<0.05;1.124±0.133,1.016±0.107vs1.392±0.113,P<0.05),β-折叠(3.397±0.225,3.433±0.236vs2.486±0.198,P<0.05;2.646±0.209,2.591±0.216vs1.558±0.159,P<0.05)和转角含量(4.366±0.284,4.322±0.266vs3.127±0.272,P<0.05;2.675±0.221,2.627±0.235vs1.773±0.181,P<0.05)增加;并且mDCs比imDCs更容易受到肿瘤来源因素的影响。结论:与肿瘤细胞共培养能够导致mDCs和imDCs的脂含量和蛋白质二级结构发生改变,可能是肿瘤导致DCs功能损伤的结构基础。

Objective：To investigate the effect of tumor cells on lipid contents and protein secondary structures in dendritic cells（DCs） of different differentiation stages by Fourier transformed infrared spectrum（FT-IR）,and to provide a clue for understanding the mechanism of tumor immune escape.Methods： CD14＋monocytes were isolated by immunomagnetic beads,and the immature DCs（imDCs） and mature DCs（mDCs） were induced by classic method.The imDCs and mDCs were co-cultured with human hepatoma BEL7402 cells,erythroleukemia K562 cells or human umbilical vein endothelial cells（HUVEC） for 48 h,untreated DCs served as control.The effects of tumor cells on lipid contents and protein secondary structures of DCs at different differentiation stages were investigated by FT-IR.Results： Compared with untreated DCs,the concentration of membrane phospholipid in DCs co-cultured with BEL7402 and K562 tumor cells was significantly decreased（2.718±0.296,3.124±0.361 vs 4.855±0.324,P〈0.05;2.964±0.136,3.522±0.173 vs 4.217±0.206,P〈0.05）,the total lipid was increased（3.768±0.185,3.591±0.197 vs 2.487±0.212,P〈0.05;4.288±0.156,4.155±0.167 vs 3.233±0.206,P〈0.05）,the protein α-helix was decreased（1.863±0.192,1.754±0.169 vs 2.364±0.188,P〈0.05;1.124±0.133,1.016±0.107 vs 1.392±0.113,P〈0.05）,and the protein-sheet and β-turn were increased（3.397±0.225,3.433±0.236 vs 2.486±0.198,P〈0.05;2.646±0.209,2.591±0.216 vs1.558±0.159,P〈0.05）.Moreover,compared with imDCs,mDCs were more susceptible to tumor-derived factors（4.366±0.284,4.322±0.266 vs 3.127±0.272,P〈0.05;2.675±0.221,2.627±0.235 vs 1.773±0.181,P〈0.05）.Conclusion： Tumor cells can elicit the changes of lipid contents and protein secondary structures of imDCs and mDCs,which might be the structure basis for functional impairment caused by tumors