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目的:探讨白细胞介素11(IL11)类似物环九肽c(CGRRAGGSC)与人前列腺癌PC-3细胞的体外结合特性。方法:采用荧光染料LSS670标记c(CGRRAGGSC)合成LSS670-c(CGRRAGGSC),流式细胞仪测定其与PC-3细胞体外结合的荧光强度,计算其竞争抑制试验中的半数抑制量(IC50)和平衡抑制常数(K i),荧光显微镜观察LSS670-c(CGRRAGGSC)在PC-3细胞的定位;用99mTc标记c(CGRRAGGSC)合成99mTc-DTPA-c(CGRRAGGSC)与PC-3细胞进行放射受体结合分析,Scatchard作图法计算标记物与PC-3细胞结合的平衡解离常数(Kd)和每个细胞上的最大结合位点数(Bm ax)。结果:LSS670-c(CGRRAGGSC)与人前列腺癌PC-3细胞的结合具有可饱和性,浓度与时间呈依赖性。未标记c(CGRRAGGSC)与LSS670-c(CGRRAGGSC)对PC-3受体具有竞争性抑制作用[IC50=(6.31±0.12)nmol/L,Ki=(2.11±0.14)nmol/L]。LSS670-c(CGRRAGGSC)荧光主要集中在PC-3细胞膜上,Kd值为(0.11±0.02)nmol/L,Bm ax为(230±34)fmol/mg pro。结论:c(CGRRAGGSC)符合特异性配体的标准。
Objective: To investigate the in vitro binding characteristics of interleukin 11 (IL11) analogue cyclic nonapeptide C (CGRRAGGSC) to human prostate cancer PC-3 cells. Methods: LSS670-c (CGRRAGGSC) was synthesized by fluorescent labeling of CGRRAGGSC and the fluorescence intensity of LSS670-c was measured by flow cytometry in vitro. The half inhibitory concentration (IC50) and The inhibitory constant (K i) was determined by fluorescence microscope. The localization of LSC670-c (CGRRAGGSC) in PC-3 cells was observed by fluorescence microscopy. 99mTc-DTPA-c (CGRRAGGSC) and PC- For binding analysis, the equilibrium dissociation constants (Kd) of labels bound to PC-3 cells and the maximum number of binding sites per cell (Bm ax) were calculated by Scatchard plotting. Results: The binding of LSS670-C (CGRRAGGSC) to human prostate cancer PC-3 cells was saturable in a time-and concentration-dependent manner. The unlabeled c (CGRRAGGSC) and the CGRRAGGSC had a competitive inhibitory effect on PC-3 receptor [IC50 = (6.31 ± 0.12) nmol / L, Ki = (2.11 ± 0.14) nmol / L]. The fluorescence of LSS670-c (CGRRAGGSC) mainly concentrated on the membrane of PC-3 cells with a Kd of (0.11 ± 0.02) nmol / L and a Bm ax of (230 ± 34) fmol / mg pro. Conclusion: c (CGRRAGGSC) conformed to the standard of specific ligand.