Nadeau Amélie, Tsering Thupten, Abdouh Mohamed, Kienzle Laura, Cleyle Jenna, Taylor Lorne, Douanne Noélie, Dickinson Kyle, Siegel Peter M, Burnier Julia V
Cancer Research Program, Research Institute of the McGill University Health Centre, Montreal, QC, Canada.
Department of Pathology, McGill University, Montreal, QC, Canada.
J Exp Clin Cancer Res. 2025 May 23;44(1):157. doi: 10.1186/s13046-025-03418-3.
While primary breast cancer (BC) is often effectively managed, metastasis remains the primary cause of BC-related fatalities. Gaps remain in our understanding of the mechanisms regulating cancer cell organotropism with predilection to specific organs. Unraveling mediators of site-specific metastasis could enhance early detection and enable more tailored interventions. Liquid biopsy represents an innovative approach in cancer involving the analysis of biological materials such as circulating tumor DNA and tumor-derived extracellular vesicles (EV) found in body fluids like blood or urine. This offers valuable insights for characterizing and monitoring tumor genomes to advance personalized medicine in metastatic cancers.
We performed in-depth analyses of EV cargo associated with BC metastasis using eight murine cell line models with distinct metastatic potentials and organotropism to the lung, the bone, the liver, and the brain. We characterized the secretome of these cells to identify unique biomarkers specific to metastatic sites.
Small EVs isolated from all cell lines were quantified and validated for established EV markers. Tracking analysis and electron microscopy revealed EV secretion patterns that differed according to cell line. Cell-free (cf)DNA and EV-associated DNA (EV-DNA) were detected from all cell lines with varying concentrations. We detected a TP53 mutation in both EV-DNA and cfDNA. Mass spectrometry-based proteomics analyses identified 698 EV-associated proteins, which clustered according to metastatic site. This analysis highlighted both common EV signatures and proteins involved in cancer progression and organotropism unique to metastatic cell lines. Among these, 327 significantly differentially enriched proteins were quantified with high confidence levels across BC and metastatic BC cells. We found enrichment of specific integrin receptors in metastatic cancer EVs compared to EVs secreted from non-transformed epithelial cells and matched tumorigenic non-metastatic cells. Pathway analyses revealed that EVs derived from parental cancer cells display a cell adhesion signature and are enriched with proteins involved in cancer signaling pathways.
Taken together, the characterization of EV cargo in a unique model of BC organotropism demonstrated that EV-DNA and EV proteomes were informative of normal and cancer states. This work could help to identify BC biomarkers associated with site-specific metastasis and new therapeutic targets.
虽然原发性乳腺癌（BC）通常能得到有效治疗，但转移仍然是BC相关死亡的主要原因。我们对调节癌细胞器官趋向性（倾向于特定器官）的机制的理解仍存在差距。阐明位点特异性转移的介质可以加强早期检测并实现更具针对性的干预措施。液体活检是癌症领域的一种创新方法，涉及分析生物材料，如在血液或尿液等体液中发现的循环肿瘤DNA和肿瘤来源的细胞外囊泡（EV）。这为表征和监测肿瘤基因组以推进转移性癌症的个性化医疗提供了有价值的见解。
我们使用八个具有不同转移潜能和对肺、骨、肝和脑的器官趋向性的小鼠细胞系模型，对与BC转移相关的EV货物进行了深入分析。我们对这些细胞的分泌组进行了表征，以鉴定特定于转移部位的独特生物标志物。
从所有细胞系中分离出的小EV被定量并针对已确定的EV标志物进行了验证。追踪分析和电子显微镜显示，EV分泌模式因细胞系而异。在所有细胞系中均检测到游离（cf）DNA和与EV相关的DNA（EV-DNA），其浓度各不相同。我们在EV-DNA和cfDNA中均检测到TP53突变。基于质谱的蛋白质组学分析鉴定出698种与EV相关的蛋白质，这些蛋白质根据转移部位进行了聚类。该分析突出了常见的EV特征以及参与癌症进展和转移性细胞系特有的器官趋向性的蛋白质。其中，在BC细胞和转移性BC细胞中，有327种显著差异富集的蛋白质被高置信度定量。与非转化上皮细胞和匹配的致瘤性非转移性细胞分泌的EV相比，我们发现转移性癌症EV中特定整合素受体富集。通路分析表明，源自亲代癌细胞的EV表现出细胞粘附特征，并富含参与癌症信号通路的蛋白质。
总之，在独特的BC器官趋向性模型中对EV货物的表征表明，EV-DNA和EV蛋白质组能够反映正常和癌症状态。这项工作有助于识别与位点特异性转移相关的BC生物标志物和新的治疗靶点。
