Bladder carcinoma (BC) is the tenth most frequent malignancy worldwide, with high morbidity and mortality rates. Despite recent treatment advances, high-grade BC and muscle-invasive BC present with significant progression and recurrence rates, urging the need for alternative treatments. The microRNA-21 (miR-21) has superexpression in many malignancies and is associated with cellular invasion and progression. One of its mechanisms of action is the regulation of RECK, a tumor suppressor gene responsible for inhibiting metalloproteinases, including MMP9. In a high-grade urothelial cancer cell line, we aimed to assess if miR-21 downregulation would promote RECK expression and decrease MMP9 expression. We also evaluated cellular migration and proliferation potential by inhibition of this pathway. In a T24 cell line, we inhibited miR-21 expression by transfection of a specific microRNA inhibitor (anti-miR-21). There were also control and scramble groups, the last with a negative microRNA transfected. After the procedure, we performed a genetic expression analysis of miR-21, RECK, and MMP9 through qPCR. Migration, proliferation, and protein expression were evaluated via wound healing assay, colony formation assay, flow cytometry, and immunofluorescence.After anti-miR-21 transfection, miR-21 expression decreased with RECK upregulation and MMP9 downregulation. The immunofluorescence assay showed a significant increase in RECK protein expression (p < 0.0001) and a decrease in MMP9 protein expression (p = 0.0101). The anti-miR-21 transfection significantly reduced cellular migration in the wound healing assay (p < 0.0001). Furthermore, in the colony formation assay, the anti-miR-21 group demonstrated reduced cellular proliferation (p = 0.0008), also revealed in the cell cycle analysis by flow cytometry (p = 0.0038). Our results corroborate the hypothesis that miR-21 is associated with BC cellular migration and proliferation, revealing its potential as a new effective treatment for this pathology.

膀胱癌（BC）是全球第十常见的恶性肿瘤，发病率和死亡率很高。尽管最近的治疗取得了进展，但高级别 BC 和肌肉侵袭性 BC 仍具有显着的进展率和复发率，迫切需要替代治疗。 microRNA-21 (miR-21) 在许多恶性肿瘤中超表达，并与细胞侵袭和进展相关。其作用机制之一是调节 RECK，这是一种肿瘤抑制基因，负责抑制金属蛋白酶，包括 MMP9。在高级尿路上皮癌细胞系中，我们旨在评估 miR-21 下调是否会促进 RECK 表达并降低 MMP9 表达。我们还通过抑制该途径评估了细胞迁移和增殖潜力。在 T24 细胞系中，我们通过转染特定的 microRNA 抑制剂（抗 miR-21）来抑制 miR-21 表达。还有对照组和混杂组，最后一组转染了阴性 microRNA。手术后，我们通过 qPCR 对 miR-21、RECK 和 MMP9 进行基因表达分析。通过伤口愈合实验、集落形成实验、流式细胞术和免疫荧光评估迁移、增殖和蛋白表达。抗miR-21转染后，随着RECK上调和MMP9下调，miR-21表达下降。免疫荧光检测显示 RECK 蛋白表达显着增加 ( p  < 0.0001)，MMP9 蛋白表达显着降低 ( p  = 0.0101)。在伤口愈合试验中，抗 miR-21 转染显着减少了细胞迁移 ( p  < 0.0001)。此外，在集落形成测定中，抗 miR-21 组表现出细胞增殖减少 ( p  = 0.0008)，流式细胞术的细胞周期分析也显示出这一点 ( p  = 0.0038)。我们的结果证实了 miR-21 与 BC 细胞迁移和增殖相关的假设，揭示了其作为这种病理学新的有效治疗方法的潜力。