Laboratory of Pathology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA.
Urologic Oncology Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA.
Genes (Basel). 2024 Jul 11;15(7):905. doi: 10.3390/genes15070905.
Renal cell carcinoma is one of the ten more common malignant tumors worldwide, with a high incidence and mortality rate. Kidney cancer frequently presents at an advanced stage, and it is almost invariably fatal. Much progress has been made in identifying molecular targets for therapy in the hope of improving survival rates, but still, we have no good markers for early detection or progression of the disease. Von Hippel Lindau syndrome (VHL) is an autosomal dominant cancer hereditary syndrome in which affected individuals are at risk of developing bilateral and multifocal renal cell carcinomas (RCC) as well as other tumors. These patients provide an ideal platform to investigate the potential of urinary exosomal miRNA biomarkers in the early development of ccRCC, as these patients are regularly imaged and tumors are actively monitored until the tumor reaches 3 cm before surgical excision. This allows for pre- and post-surgical urine collection and comparison to excised tumor tissues. Studying different biomarkers in urine can provide comprehensive molecular profiling available to patients and physicians and can be a great source of additional tumor genetic information.
Pre- and postoperative urine samples were obtained from a cohort of VHL patients undergoing surveillance and surgical excision of ccRCCs, and exosomes were extracted. MicroRNA-Seq analysis was performed on miRNA extracted from both urine-derived exosomes and FFPE material from excised ccRCCs.
MicroRNA-Seq analysis highlighted a significant difference in the urinary exosome-derived miRNA expression profiles between VHL patients and normal control individuals. This included decreased expression of the miR-320 family, such as miR-320a, known to be decreased in sporadic ccRCC and suppressed by the HIF1α transcription factor activated by the loss of the VHL gene. MiR-542-5p represented a potential marker of VHL-associated ccRCC that was lowly expressed in normal control urinary exosomes, significantly increased in the preoperative urinary exosomes of tumor-bearing VHL patients, and subsequently reduced to normal levels of expression after tumor excision. In concordance with this, the expression of miR-542-5p was increased in the VHL-associated ccRCC in comparison to the normal kidney.
This study shows the potential for miRNA profiling of exosomes from readily available biofluids to both distinguish VHL patient urine from normal control urine microRNAs and to provide biomarkers for the presence of VHL syndrome-associated ccRCC. Further validation studies are necessary to demonstrate the utility of urinary exosome-derived miRNAs as biomarkers in kidney cancer.
肾细胞癌是全球十大常见恶性肿瘤之一，发病率和死亡率都很高。肾癌常发生在晚期，几乎总是致命的。在确定治疗的分子靶标方面已经取得了很大进展，希望能提高生存率，但我们仍然没有用于早期发现或疾病进展的良好标志物。von Hippel-Lindau 综合征（VHL）是一种常染色体显性遗传性癌症综合征，受影响的个体有发生双侧和多灶性肾细胞癌（RCC）以及其他肿瘤的风险。这些患者为研究尿液外泌体 miRNA 标志物在 ccRCC 早期发展中的潜力提供了理想的平台，因为这些患者定期进行影像学检查，并积极监测肿瘤，直到肿瘤达到 3 厘米后再进行手术切除。这允许在手术前和手术后采集尿液并与切除的肿瘤组织进行比较。研究尿液中的不同生物标志物可以为患者和医生提供全面的分子谱，并可以成为额外肿瘤遗传信息的重要来源。
从接受 VHL 患者的监测和 ccRCC 手术切除的队列中获得术前和术后尿液样本，并提取外泌体。对从尿液衍生的外泌体和从切除的 ccRCC 的 FFPE 材料中提取的 miRNA 进行 miRNA-Seq 分析。
miRNA-Seq 分析突出了 VHL 患者和正常对照个体之间尿液外泌体衍生 miRNA 表达谱的显著差异。这包括 miR-320 家族的表达降低，如 miR-320a，在散发性 ccRCC 中降低，并被 VHL 基因缺失激活的 HIF1α 转录因子抑制。miR-542-5p 是 VHL 相关 ccRCC 的一个潜在标志物，在正常对照尿外泌体中表达水平低，在肿瘤携带 VHL 患者的术前尿外泌体中显著增加，并且在肿瘤切除后恢复到正常表达水平。与此一致的是，miR-542-5p 在 VHL 相关 ccRCC 中的表达高于正常肾脏。
这项研究表明，从易于获得的生物体液中对 exosomes 进行 miRNA 谱分析，不仅可以区分 VHL 患者尿液与正常对照尿液中的 miRNAs，还可以为 VHL 综合征相关 ccRCC 的存在提供生物标志物。需要进一步的验证研究来证明尿液外泌体衍生的 miRNAs 作为肾癌生物标志物的效用。
