PO.CL01.23 · 临床研究
用于转移性前列腺癌循环肿瘤细胞检测的下一代液体活检
Next-generation liquid biopsy for circulating tumor cell detection in metastatic prostate cancer
作者与单位 Authors & Affiliations
摘要 Abstract
中文摘要
前列腺癌(PCa)是加拿大男性中最常被诊断出的恶性肿瘤,而转移性疾病(mPCa)预后不良。分析循环肿瘤细胞(CTCs)的液体活检提供了一种微创的疾病评估工具,但常用的CTC标志物(如EpCAM)在PCa中表达差异较大,尤其是在晚期或治疗抵抗的情况下。需要更可靠的生物标志物来改善CTC检测和患者分层。我们使用了针对STEAP1(一种在PCa中高度过表达而在正常组织中极少存在的跨膜蛋白)的单克隆抗体,并将其整合到成像流式细胞术(imFC)CTC检测中,以检测和表征CTCs。来自局限性和转移性PCa患者的CTCs通过Ficoll密度梯度分离,并用DAPI、CD45、EpCAM和STEAP1抗体染色。高内涵图像通过一个结合了机器学习分类的计算流程进行分析,以识别并分类完整的CTCs、CTC碎片以及被免疫细胞内化的肿瘤来源细胞外囊泡(EVs)。在大多数转移性患者中检测到STEAP1⁺ CTCs,包括那些未检测到EpCAM⁺ CTCs的个体,这凸显了仅依赖EpCAM检测的局限性。与局限性或稳定性疾病患者相比,活动性疾病患者表现出更高的STEAP1⁺ CTC计数。此外,在CD45⁺免疫细胞内观察到STEAP1⁺细胞外囊泡和CTC碎片,提示可通过该平台测量更广泛的肿瘤-免疫相互作用。我们进一步将该工作流程拓展到一项临床研究中,评估接受Pluvicto治疗的患者中表达不同PCa生物标志物(PSMA、STEAP1和STEAP2)的CTC丰度的治疗相关变化。在该研究中,CTCs使用Parsortix微流控捕获平台进行富集。早期结果表明,在PSMA表达低或波动的患者中,STEAP家族标志物仍可检测到,支持其在监测治疗反应中的价值。综上所述,这些发现将STEAP1、STEAP2和PSMA定位为下一代基于CTC的液体活检的可靠生物标志物,并展示了它们在提高mPCa诊断敏感性和治疗监测方面的潜力。
查看英文原文 English abstract
Prostate cancer (PCa) is the most frequently diagnosed malignancy among Canadian men, and metastatic disease (mPCa) carries a poor prognosis. Liquid biopsy that analyzing circulating tumor cells (CTCs) provide a minimally invasive tool for disease assessment, yet commonly used CTC markers such as EpCAM show variable expression in PCa, especially in advanced or treatment-resistant settings. More reliable biomarkers are needed to improve CTC detection and patient stratification. We use monoclonal antibodies against STEAP1, a transmembrane protein highly overexpressed in PCa but minimally present in normal tissues, and integrated them into an imaging flow cytometry (imFC) CTC assay to detect and characterize CTCs. CTCs from localized and metastatic PCa patients were isolated using Ficoll density gradients and stained with DAPI, CD45, EpCAM, and STEAP1 antibodies. High-content images were analyzed through a computational pipeline incorporating machine-learning classification to identify and classify intact CTCs, CTC fragments, and tumor-derived extracellular vesicles (EVs) internalized by immune cells. STEAP1⁺ CTCs were detected in most metastatic patients, including individuals who lacked detectable EpCAM⁺ CTCs, highlighting the limitations of EpCAM-only assays. Patients with active disease exhibited higher STEAP1⁺ CTC counts compared with those with localized or stable disease. Additionally, STEAP1⁺ extracellular vesicles and CTC fragments were observed within CD45⁺ immune cells, suggesting broader tumor-immune interactions measurable through this platform. We further extended this workflow to a clinical study evaluating treatment-associated changes in abundance of CTC expressed with different PCa biomarkers, PSMA, STEAP1, and STEAP2 in patients receiving Pluvicto therapy. In this study, CTCs were enriched using the Parsortix microfluidic capture platform. Early results indicate that STEAP-family markers remain detectable in patients with low or fluctuating PSMA expression, supporting their value in monitoring therapeutic response. Together, these findings position STEAP1, STEAP2 and PSMA as robust biomarkers for next-generation CTC-based liquid biopsy assays and demonstrate their potential to enhance diagnostic sensitivity and treatment monitoring in mPCa.
利益披露 Disclosure
M. Sheng, None..
O. Alawamry, None..
S. Feng, None..
U. Emmenegger, None..
K. Cimolini, None..
D. Vesprini, None..
A. Loblaw, None..
C. S. Lim, None..
S. K. Liu, None.