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目的:观察地塞米松耐药的人B细胞淋巴瘤细胞系对NK细胞杀伤敏感性的变化,并探讨其作用机制。方法:20μg/ml地塞米松(dexamethasone,DXM)诱导B细胞淋巴瘤细胞系SU-DHL-4(简称SU细胞)发生耐药,建立多药耐药细胞系SU/DXM。流式细胞术分选健康人外周血NK细胞,流式细胞术检测效靶比20∶1时,NK细胞对SU和SU/DXM细胞的杀伤效应。实时定量PCR检测SU和SU/DXM细胞表面NK细胞活化性受体(soluble NK group 2 member D,NKG2D)配体基因[可溶性MHCⅠ类分子相关A/B(MHC classⅠchain-related molecules A/B,MICA/B)及人UL16结合蛋白(UL16 binding protein,ULBP)1、2、3]的表达。结果:成功建立多药耐药细胞系SU/DXM。与SU细胞相比,SU/DXM细胞对NK细胞杀伤的敏感性明显下降[SU细胞为(11.38±3.51)%,SU/DXM细胞为(3.57±4.22)%,P<0.05],细胞表面NKG2D配体基因MICA、MICB、ULBP2 mRNA表达量降低(SU细胞分别为1.014±0.121、1.009±0.092、0.993±0.108,SU/DXM细胞分别为0.017±0.006、0.682±0.063、0.773±0.066,P<0.05或P<0.01)。结论:地塞米松能诱导B细胞淋巴瘤SU细胞发生多药耐药,多药耐药SU/DXM细胞能够抵抗NK细胞的杀伤,其机制可能与NKG2D配体基因表达量下降有关。
OBJECTIVE: To observe the changes of NK cell cytotoxicity induced by dexamethasone-resistant human B cell lymphoma cell lines and to explore its mechanism. Methods: SU-DXL-4 (SU cells) were induced by 20μg / ml dexamethasone (DXM) to establish multidrug resistant cell line SU / DXM. Flow cytometry was used to detect NK cells in peripheral blood of healthy volunteers. The killing effect of NK cells on SU and SU / DXM cells was detected by flow cytometry. Real-time quantitative PCR was used to detect the expression of soluble NK group 2 member D (NKG2D) ligand gene [soluble MHC class Ⅰ chain-related molecules A / B (MICA) / B) and UL16 binding protein (ULBP) 1, 2, 3]. Results: Multidrug resistant cell line SU / DXM was successfully established. The sensitivity of SU / DXM cells to NK cell killing was significantly lower than that of SU cells ([(11.38 ± 3.51)% for SU cells and (3.57 ± 4.22)% for SU / DXM cells, P <0.05] The expression of MICA, MICB and ULBP2 mRNA in SU / DXM cells were lower than that in SU / DXM cells (SU cells were 1.014 ± 0.121, 1.009 ± 0.092 and 0.993 ± 0.108, respectively) Or P <0.01). CONCLUSION: Dexamethasone can induce multidrug resistance in B cell lymphoma SU cells. Multidrug resistant SU / DXM cells can resist the killing of NK cells. The mechanism may be related to the decreased expression of NKG2D ligand gene.