A Circulating Tumor Cell-RNA Assay for Assessment of Androgen Receptor Signaling Inhibitor Sensitivity in Metastatic Castration-Resistant Prostate Cancer
A Circulating Tumor Cell-RNA Assay for Assessment of Androgen Receptor Signaling Inhibitor Sensitivity in Metastatic Castration-Resistant Prostate Cancer
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DOI：
10.7150/thno.34485
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发表时间：
2019-01-01
期刊：
影响因子：
12.4
通讯作者：
Posadas, Edwin M.
中科院分区：
文献类型：
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作者：
Jan, Yu Jen;Yoon, Junhee;Posadas, Edwin M.
基本原理：我们的目标是开发一种循环肿瘤细胞（CTC）-RNA测定法，用于表征临床相关的RNA特征，以评估转移性去势抵抗性前列腺癌（mCRPC）患者对雄激素受体信号传导抑制剂（ARSI）的敏感性。我们开发了NanoVelcro CTC-RNA检测，通过结合热响应（TR）-NanoVelcro CTC纯化系统与NanoString nCounter平台用于细胞纯化和RNA分析。基于经过充分验证的基于组织的前列腺癌分类系统（PCS），我们专注于最具侵袭性和ARSI抗性的PCS亚型，即，PCS 1，用于CTC分析。我们应用严格的生物信息学过程来开发CTC-PCS 1组，其由前列腺癌（PCa）CTC特异性RNA特征组成，在背景白色血细胞（WBC）中具有最小表达。我们使用充分表征的PCa细胞系验证了NanoVelcro CTC-RNA检测试剂盒和CTC-PCS 1样本组，以证明该检测试剂盒的灵敏度和动态范围，以及PCS 1 Z评分（PCS 1亚型的似然估计值）用于鉴别PCS 1亚型和ARSI耐药性的特异性。然后，我们从23名接受ARSI的PCa患者中选择了31份血液样本进行检测。结果：使用PCa细胞系样本的验证研究表明，NanoVelcro CTC-RNA检测可以检测CTC-PCS 1组中的RNA转录本，在5-100个细胞的动态范围内具有高灵敏度和线性。我们还表明，CTC-PCS 1组中的基因在PCa细胞系中高度表达，而在背景WBC中低表达。使用模拟血液样本条件的人工CTC样本，我们进一步证明了CTC-PCS 1面板在识别PCS 1样样本方面具有高度特异性，并且高PCS 1 Z评分与ARSI耐药样本相关。在患者血液中，与ARSI敏感样本（ARSI-S，n= 17）相比，ARSI耐药样本（ARSI-R，n= 14）具有显著更高的PCS 1 Z评分（秩和检验，P=0.003）。在对8例最初对ARSI敏感（ARSI-S），后来发展为耐药（ARSI-R）的患者的分析中，我们发现从ARSI-S到ARSI-R的时间，PCS 1 Z评分增加（成对T检验，P=0.016）。使用我们的新方法，我们开发了一流的CTC-RNA分析，并证明了将临床相关的基于组织的RNA分析如PCS转化为CTC测试的可行性。这种方法允许以非侵入性方式检测与临床耐药性相关的RNA表达，这可以促进患者特异性治疗选择和耐药性的早期检测，这是精确肿瘤学的目标。
Rationale: Our objective was to develop a circulating tumor cell (CTC)-RNA assay for characterizing clinically relevant RNA signatures for the assessment of androgen receptor signaling inhibitor (ARSI) sensitivity in metastatic castration-resistant prostate cancer (mCRPC) patients.Methods: We developed the NanoVelcro CTC-RNA assay by combining the Thermoresponsive (TR)-NanoVelcro CTC purification system with the NanoString nCounter platform for cellular purification and RNA analysis. Based on the well-validated, tissue-based Prostate Cancer Classification System (PCS), we focus on the most aggressive and ARSI-resistant PCS subtype, i.e., PCS1, for CTC analysis. We applied a rigorous bioinformatic process to develop the CTC-PCS1 panel that consists of prostate cancer (PCa) CTC-specific RNA signature with minimal expression in background white blood cells (WBCs). We validated the NanoVelcro CTC-RNA assay and the CTC-PCS1 panel with well-characterized PCa cell lines to demonstrate the sensitivity and dynamic range of the assay, as well as the specificity of the PCS1 Z score (the likelihood estimate of the PCS1 subtype) for identifying PCS1 subtype and ARSI resistance. We then selected 31 blood samples from 23 PCa patients receiving ARSIs to test in our assay. The PCS1 Z scores of each sample were computed and compared with ARSI treatment sensitivity.Results: The validation studies using PCa cell line samples showed that the NanoVelcro CTC-RNA assay can detect the RNA transcripts in the CTC-PCS1 panel with high sensitivity and linearity in the dynamic range of 5-100 cells. We also showed that the genes in CTC-PCS1 panel are highly expressed in PCa cell lines and lowly expressed in background WBCs. Using the artificial CTC samples simulating the blood sample conditions, we further demonstrated that the CTC-PCS1 panel is highly specific in identifying PCS1-like samples, and the high PCS1 Z score is associated with ARSI resistance samples. In patient bloods, ARSI-resistant samples (ARSI-R, n=14) had significantly higher PCS1 Z scores as compared with ARSI-sensitive samples (ARSI-S, n=17) (Rank-sum test, P=0.003). In the analysis of 8 patients who were initially sensitive to ARSI (ARSI-S) and later developed resistance (ARSI-R), we found that the PCS1 Z score increased from the time of ARSI-S to the time of ARSI-R (Pairwise T-test, P=0.016).Conclusions: Using our new methodology, we developed a first-in-class CTC-RNA assay and demonstrated the feasibility of transforming clinically-relevant tissue-based RNA profiling such as PCS into CTC tests. This approach allows for detecting RNA expression relevant to clinical drug resistance in a non-invasive fashion, which can facilitate patient-specific treatment selection and early detection of drug resistance, a goal in precision oncology.