Division of Experimental Oncology/Unit of Urology; URI; IRCCS Ospedale San Raffaele, Milan, Italy.
Department of Medical Biotechnology and Translational Medicine, University of Milano, Segrate, Italy.
Sci Rep. 2017 Feb 13;7:42157. doi: 10.1038/srep42157.
The inhibitory effects demonstrated by activation of cannabinoid receptors (CB) on cancer proliferation and migration may also play critical roles in controlling bladder cancer (BC). CB expression on human normal and BC specimens was tested by immunohistochemistry. Human BC cells RT4 and RT112 were challenged with CB agonists and assessed for proliferation, apoptosis, and motility. Cellular sphingolipids (SL) constitution and metabolism were evaluated after metabolic labelling. CB1-2 were detected in BC specimens, but only CB2 was more expressed in the tumour. Both cell lines expressed similar CB2. Exposure to CB2 agonists inhibited BC growth, down-modulated Akt, induced caspase 3-activation and modified SL metabolism. Baseline SL analysis in cell lines showed differences linked to unique migratory behaviours and cytoskeletal re-arrangements. CB2 activation changed the SL composition of more aggressive RT112 cells by reducing (p < 0.01) Gb3 ganglioside (-50 ± 3%) and sphingosine 1-phosphate (S1P, -40 ± 4%), which ended up to reduction in cell motility (-46 ± 5%) with inhibition of p-SRC. CB2-selective antagonists, gene silencing and an inhibitor of SL biosynthesis partially prevented CB2 agonist-induced effects on cell viability and motility. CB2 activation led to ceramide-mediated BC cell apoptosis independently of SL constitutive composition, which instead was modulated by CB2 agonists to reduce cell motility.
大麻素受体（CB）的激活对癌症增殖和迁移的抑制作用也可能在控制膀胱癌（BC）方面发挥关键作用。通过免疫组织化学测试了人正常和 BC 标本上的 CB 表达。用 CB 激动剂刺激人 BC 细胞 RT4 和 RT112，并评估增殖、凋亡和迁移。在代谢标记后评估细胞神经鞘脂（SL）组成和代谢。在 BC 标本中检测到 CB1-2，但仅 CB2 在肿瘤中表达更高。两种细胞系均表达相似的 CB2。暴露于 CB2 激动剂可抑制 BC 生长、下调 Akt、诱导 caspase 3 激活并改变 SL 代谢。细胞系中的基线 SL 分析显示与独特的迁移行为和细胞骨架重排相关的差异。CB2 激活通过减少（p < 0.01）Gb3 神经节苷脂（-50 ± 3%）和 1-磷酸鞘氨醇（S1P，-40 ± 4%）来改变更具侵袭性的 RT112 细胞的 SL 组成，从而导致细胞迁移减少（-46 ± 5%），并抑制 p-SRC。CB2 选择性拮抗剂、基因沉默和 SL 生物合成抑制剂部分阻止了 CB2 激动剂对细胞活力和迁移的影响。CB2 激活导致神经酰胺介导的 BC 细胞凋亡，独立于 SL 组成成分，而 CB2 激动剂则通过调节 SL 来减少细胞迁移。
