Department of Molecular Medicine and Medical Biothecnology, University Federico II, 80131 Napoli, Italy.
Laboratory of Virology and Immunology, GIGA-R, B34, University of Liege, B-4000 Liege, Belgium.
Cells. 2021 Sep 9;10(9):2366. doi: 10.3390/cells10092366.
Despite Glioblastoma (GBM) frequently expressing programmed cell death ligand-1 (PD-L1), treatment with anti-programmed cell death-1 (PD1) has not yielded brilliant results. Intratumor variability of PD-L1 can impact determination accuracy. A previous study on mouse embryonic fibroblasts (MEFs) reported a role for cyclin-D in control of PD-L1 expression. Because tumor-cell growth within a cancer is highly heterogeneous, we looked at whether PD-L1 and its cochaperone FKBP51s were influenced by cell proliferation, using U251 and SF767 GBM-cell-lines. PD-L1 was measured by Western blot, flow cytometry, confocal-microscopy, quantitative PCR (qPCR), by qPCR, FKBP51s by Western blot and confocal-microscopy. Chromatin-Immunoprecipitation assay (xChIp) served to assess the DNA-binding of FKBP51 isoforms. In the course of cell culture, PD-L1 appeared to increase concomitantly to cyclin-D on G1/S transition, to decrease during exponential cell growth progressively. We calculated a correlation between and gene expression levels. In the temporal window of and peak, FKBP51s localized in ER. When cyclin-D declined, FKBP51s went nuclear. XChIp showed that FKBP51s binds gene in a closed-chromatin configuration. Our finding suggests that the dynamism of PD-L1 expression in GBM follows cyclin-D fluctuation and raises the hypothesis that FKBP51s might participate in the events that govern cyclin-D oscillation.
尽管胶质母细胞瘤（GBM）经常表达程序性细胞死亡配体-1（PD-L1），但抗程序性细胞死亡-1（PD1）的治疗并未产生显著效果。PD-L1 在肿瘤内的变异性可能会影响测定的准确性。先前在小鼠胚胎成纤维细胞（MEFs）上的研究报告了细胞周期蛋白-D 在控制 PD-L1 表达中的作用。由于癌症内的肿瘤细胞生长高度异质，我们研究了 PD-L1 及其共伴侣 FKBP51s 是否受到细胞增殖的影响，使用 U251 和 SF767 GBM 细胞系。通过 Western blot、流式细胞术、共聚焦显微镜、定量 PCR（qPCR）测量 PD-L1，通过 Western blot 和共聚焦显微镜测量 FKBP51s。染色质免疫沉淀测定（xChIp）用于评估 FKBP51 同工型的 DNA 结合。在细胞培养过程中，PD-L1 似乎在 G1/S 转换时与细胞周期蛋白-D 同时增加，在指数细胞生长过程中逐渐减少。我们计算了 基因表达水平之间的相关性。在 基因表达的时间窗口中，FKBP51s 定位于 ER 中。当细胞周期蛋白-D 下降时，FKBP51s 进入细胞核。xChIp 显示 FKBP51s 以封闭染色质构象结合 基因。我们的发现表明，GBM 中 PD-L1 表达的动态变化遵循细胞周期蛋白-D 的波动，并提出 FKBP51s 可能参与调控细胞周期蛋白-D 振荡的假说。
