CAFs源性外泌体miR-92a-3p促进膀胱癌转移的作用和机制

Muscle invasive bladder cancer (MIBC) patients have poor prognosis, especially in the metastatic cases. The mechanism of metastasis is not clear in MIBC. Lately, we found the density of cancer-associated fibroblasts (CAFs) were related with lymph node metastasis and short overall survival in bladder cancer. Next, we found that exosomal miR-92a-3p from CAFs of MIBC inhibited the expression of KLF4 and increased the ability of migration and invasion in bladder cancer cells. Furthermore, miR-92a-3p induced the expression of IL-1β in bladder cancer cells, which educated normal fibroblasts (NFs) to transfer into CAFs. In this study, we aim to disclose the mechanism involved in metastasis of bladder cancer via which exosomal miR-92a-3p regulate KLF4, to reveal miR-92a-3p increase the secretion of IL-1β and then induce the transition of NFs into CAFs, using a series of protein expression and cellular function experiments in cell and animal models, including large clinical samples. To determine the prognostic and progressive marker of exosomal miR-92a-3p in blood and urine from MIBC patients. Our study is about to provide evidence that CAFs exosomal miR-92a-3p-KLF4-IL-1β signal pathway is involved in metastasis of bladder cancer, and suggest miR-92a-3p as a prognostic and therapeutic target in bladder cancer.

膀胱癌(BC)发生转移是患者死亡的主要原因，但机制不清楚。我们前期发现肿瘤相关性成纤维细胞（CAFs）密度高与BC转移及预后差正相关。预实验结果显示：①CAFs源性外泌体miR-92a-3p靶向KLF4促进BC细胞迁移侵袭；②miR-92a-3p刺激BC细胞分泌IL-1β转化正常纤维细胞（NFs）成CAFs。本项目拟通过一系列体内外实验，明确miR-92a-3p调控KLF4的分子机制及其下游传导通路；探究miR-92a-3p通过IL-1β驯化NFs成CAFs的作用机理；探明miR-92a-3p在BC患者血液及尿液中判断预后及预测转移的临床意义；深入阐述CAFs源性外泌体miR-92a-3p调控KLF4、增加CAFs群落及促进BC转移的确切机制和肿瘤学意义，为诠释BC进展机理、寻找转移标记物及抗癌治疗新靶点提供理论依据。

在本项目资助下，课题组正在制作大样本量的膀胱癌组织芯片中（计划目标为600例，包括收集所有病理相关指标、临床预后及治疗相关指标，预计2023年底完成），在膀胱癌新鲜组织中原代培养成功CAFs和NFs并鉴定，并对CAFs源性外泌体的提取、鉴定和促癌细胞侵袭能力进行了研究，进一步研究证实CAFs源性外泌体miR-92a-3p是促进膀胱癌细胞迁移和侵袭的主要驱动因子；并揭示miR-92a-3p是通过调控KLF4促进膀胱癌细胞的迁移能力；另外还发现miR-92a-3p刺激泌膀胱癌细胞分泌IL-1β驯化NFs向CAFs转化，从而不断刺激膀胱癌进行转移的正向循环机制。我们的研究初步证实miR-92a-3p-KLF4-IL-1β信号传导通路参与了膀胱癌的转移，为将来临床针对CAFs源性外泌体miR-92a-3p在膀胱癌的靶向治疗提供了一定的理论基础。