Department of Pharmacology, School of Medicine, China Medical University, Taichung, Taiwan; Department of Biotechnology, Asia University, Taichung, Taiwan.
Graduate Institute of Biomedical Sciences, China Medical University, Taichung, Taiwan.
Neuropharmacology. 2019 Jan;144:143-154. doi: 10.1016/j.neuropharm.2018.10.033. Epub 2018 Oct 23.
Glioblastoma (GBM), the most aggressive brain tumor, has a poor prognosis due to the ease of migration to surrounding healthy brain tissue. Recent studies have shown that bradykinin receptors are involved in the progression of various cancers. However, the molecular mechanism and pathological role of bradykinin receptors remains unclear. We observed the expressions of two major bradykinin receptors, B1R and B2R, in two different human GBM cell lines, U87 and GBM8901. Cytokine array analysis showed that bradykinin increases the production of interleukin (IL)-8 in GBM via B1R. Higher B1R levels correlate with IL-8 expression in U87 and GBM8901. We observed increased levels of phosphorylated STAT3 and SP-1 in the nucleus as well. Using chromatin immunoprecipitation assay, we found that STAT3 and SP-1 mediate IL-8 expression, which gets abrogated by the inhibition of FAK and STAT3. We further demonstrated that IL-8 expression and cell migration are also regulated by the SP-1. In addition, expression levels of STAT3 and SP-1 positively correlate with clinicopathological grades of gliomas. Interestingly, our results found that inhibition of HDAC increases IL-8 expression. Moreover, stimulation with bradykinin caused increases in acetylated SP-1 and p300 complex formation, which are abrogated by inhibition of FAK and STAT3. Meanwhile, knockdown of SP-1 and p300 decreased the augmentation of bradykinin-induced IL-8 expression. These results indicate that bradykinin-induced IL-8 expression is dependent on B1R which causes phosphorylated STAT3 and acetylated SP-1 to translocate to the nucleus, hence resulting in GBM migration.
脑胶质瘤（GBM）是最具侵袭性的脑肿瘤，由于容易迁移到周围健康的脑组织而预后不良。最近的研究表明，缓激肽受体参与了各种癌症的进展。然而，缓激肽受体的分子机制和病理作用仍不清楚。我们观察了两种不同的人 GBM 细胞系 U87 和 GBM8901 中两种主要缓激肽受体 B1R 和 B2R 的表达。细胞因子阵列分析表明，缓激肽通过 B1R 增加 GBM 中白细胞介素（IL）-8 的产生。U87 和 GBM8901 中 B1R 水平较高与 IL-8 表达相关。我们还观察到核内磷酸化 STAT3 和 SP-1 的水平增加。通过染色质免疫沉淀试验，我们发现 STAT3 和 SP-1 介导 IL-8 的表达，FAK 和 STAT3 的抑制可使其失活。我们进一步证明，IL-8 的表达和细胞迁移也受到 SP-1 的调节。此外，STAT3 和 SP-1 的表达水平与胶质瘤的临床病理分级呈正相关。有趣的是，我们的结果发现抑制组蛋白去乙酰化酶（HDAC）可增加 IL-8 的表达。此外，缓激肽刺激导致乙酰化 SP-1 和 p300 复合物形成增加，FAK 和 STAT3 的抑制可使其失活。同时，SP-1 和 p300 的敲低降低了缓激肽诱导的 IL-8 表达的增强。这些结果表明，缓激肽诱导的 IL-8 表达依赖于 B1R，它导致磷酸化 STAT3 和乙酰化 SP-1 易位到核内，从而导致 GBM 迁移。
