Cancer Letters 469 (2020) 355–366 Contents lists available at ScienceDirect Cancer Letters journal homepage: www.elsevier.com/locate/canlet Original Articles PD-L1+ aneuploid circulating tumor endothelial cells (CTECs) exhibit T resistance to the checkpoint blockade immunotherapy in advanced NSCLC patients Lina Zhanga,1, Xinyong Zhangb,1, Yanxia Liua,b, Tongmei Zhangb, Ziyu Wanga, Meng Gua, ∗∗ ∗ Yilin Lic, Daisy Dandan Wangd, Weiying Lia, , Peter Ping Lind, a Department of Cellular and Molecular Biology, Beijing Chest Hospital, Capital Medical University, Beijing Tuberculosis and Thoracic Tumor Research Institute, Beijing, China b Department of Medical Oncology, Beijing Chest Hospital, Capital Medical University, Beijing Tuberculosis and Thoracic Tumor Research Institute, Beijing, China c Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Department of GI Oncology, Peking University Cancer Hospital & Institute, Beijing, China d Cytelligen, San Diego, CA, USA ARTICLE INFO ABSTRACT Keywords: Sustained angiogenesis and increased PD-L1 expression on endothelial and carcinoma cells contribute toward Aneuploid CTC and CTEC fostering an immunosuppressive microenvironment suitable for tumor growth. PD-L1+ CTCs were reported to Post-therapeutic karyotype shifting associate with poor prognosis in NSCLC patients. However, whether or not aneuploid circulating tumor en- Cellular circulating tumor biomarker dothelial cells (CTECs) express PD-L1, then serve as a surrogate biomarker to evaluate immunotherapy efficacy Liquid biopsy remains unknown. In this study, a novel SE-iFISH strategy was established to comprehensively quantify and SE-iFISH characterize a full spectrum of aneuploid CTCs and CTECs in advanced NSCLC patients subjected to second-line anti-PD-1 (nivolumab) immunotherapy. In situ co-detection of diverse subtypes of aneuploid CTCs and CTECs expressing PD-L1 and Vimentin was performed. The present clinical study demonstrated that significant amounts of PD-L1+ aneuploid CTCs and CTECs could be detected in histopathologic hPD-L1- patients. In contrast to decreased PD-L1+ CTCs, the number of multiploid PD-L1+ CTECs (≥tetrasomy 8) undergoing post-therapeutic karyotype shifting increased in patients along with tumor progression following anti-PD-1 treatment. Progressive disease (PD) lung cancer patients possessing multiploid PD-L1+ CTECs had a significantly shorter PFS compared to those without PD-L1+ CTECs. In carcinoma patients, aneuploid CTCs and CTECs may exhibit a functional interplay with respect to tumor angiogenesis, progression, metastasis, and response to immunotherapy. 1. Introduction lymphocytes, T cells are the major component [2]. Cytotoxic T-lymphocyte-associate protein 4 (CTLA-4, CD152), CD80 Aberrant immune cells, sustained angiogenesis, dysfunctional an- (B7-1), and programmed cell death 1 protein (PD-1, CD279), known as giogenic vasculatures in solid tumors, and increased PD-L1 expression immune checkpoints, are inhibitory receptors expressed on diverse T on endothelial as well as neoplastic cells, all contribute toward con- cell subpopulations [3,4]. Those immune checkpoint receptors interact stituting an immunosuppressive microenvironment suitable for tumor with their relevant ligands in the tumor microenvironment, and sub- growth. In the primary lesion, where tumor cells and the host's immune sequently down-regulate T cell activation and cytolytic activity of system interact, a microenvironment favorable for cancer development tumor-infiltrating CD4+/CD8+ T cells in response to inflammatory and metastasis is fostered [1]. It has been illustrated that the tumor stimuli, thus rendering malignant cancer cells the ability to resist and microenvironment is mainly constituted by proliferating tumor cells, evade immune attack [5]. Ligands for PD-1 receptor and CD80 are infiltrating inflammatory cells, blood vessels, stroma cells andsur- programmed death-ligand 1 (PD-L1, CD274, B7–H1) and PD-L2 rounding tissue cells. Among the tumor infiltrating inflammatory (CD273, B7-DC). PD-L1 is the primary ligand for PD-1, and is ∗ Corresponding author. ∗∗ Corresponding author. E-mail addresses: [email protected] (W. Li), [email protected] (P.P. Lin). 1 These authors contributed equally to this work. https://doi.org/10.1016/j.canlet.2019.10.041 Received 25 July 2019; Received in revised form 22 October 2019; Accepted 27 October 2019 0304-3835/ © 2019 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/BY-NC-ND/4.0/). L. Zhang, et al. Cancer Letters 469 (2020) 355–366 Abbreviations LCTC/CTEC large CTC/CTEC EMT epithelial-to-mesenchymal transition ap aneuploid EndoMT endothelial-to-mesenchymal transition TEC tumor endothelial cell hPD-L1 histopathological PD-L1 expression CTEC circulating tumor endothelial cell PD progressive disease CTC circulating tumor cell iFISH immunostaining-fluorescence in situ hybridization sCTC/CTEC small CTC/CTEC overexpressed on a series of solid tumor cells, endothelial cells [6], and morphological characterized of a full spectrum of aneuploid circulating other cells in the tumor microenvironment [7]. rare cells, including CTCs and particularly CTECs in advanced NSCLC A great endeavor of cancer immunotherapies, which effectively in- patients treated with second-line anti-PD-1 (nivolumab). Expression of terrupt and inhibit the binding of immune checkpoint receptors to their PD-L1 and the mesenchymal marker Vimentin (Vim) on aneuploid ligands, have been shown to enhance T cell response to malignant CTECs and CTCs was co-detected in lung cancer patients. PD-L1+ carcinoma cells in the tumor microenvironment. USFDA approved im- CTECs, identified and characterize for the first time in the current mune checkpoint inhibitors, including immunotherapeutic monoclonal study, were found to undergo both post-therapeutic karyotype and antibodies against checkpoint receptors such as PD-1 (Keytruda pem- morphology shifting following immunotherapy. Although second-line brolizumab by Merck; Opdivo nivolumab by Bristol-Meyers Squibb), anti-PD-1 could effectively deplete the specific subtype of haploid small CTAL-4 (Yervoy ipilimumab by BMS), or against the ligand PD-L1 cell size CTCs and CTECs (≤5 μm WBCs), the quantity of multiploid (Tecentriq atezolizumab by Roche; Imfinzi durvalumab by AstraZeneca; large PD-L1+ CTECs (≥tetrasomy 8) significantly increased in im- Bavencio avelumab by Merck and Pfizer), have demonstrated unique munotherapeutic patients. Post-therapeutic NSCLC progressive disease advantages in restoring and facilitating appropriate immune response, (PD) patients possessing the specific subtype of multiploid PD-L1+ ultimately eliminating carcinoma cells [8]. CTECs showed a significantly shorter PFS compared to those who had It has been reported that among non-small cell lung cancer (NSCLC) no PD-L1+ CTEC detected, indicating that PD-L1+ CTECs were asso- patients subjected to anti-PD-1 checkpoint blockade immunotherapy, ciated with anti-PD-1 resistance and tumor progression. longer progression-free survival (PFS) and overall survival (OS) were Unlike small fragments of circulating tumor nucleic acids (ctDNA) observed in patients whose tumor cells highly expressed PD-L1 (tumor that are diluted in peripheral circulation, both CTCs and tumor angio- proportion score > 50%) [9]. Examination of PD-L1 expression on genesis related CTECs constitute a category of viable, real time “cellular cancer cells is pivotal for guiding administration of anti-PD-1 to cancer circulating tumor biomarkers”, which contain intact contents of patients. However, distribution of PD-L1+ neoplastic cells in tumors is genomic and protein expression profiles or the signatures along with not homogeneous, as those cells are clustered in the specific region tumor progression. Each sub-category of those non-hematologic aneu- where IFNγ−activated T cells infiltrate rather than diffuse in tumor ploid circulating rare cells may distinctively possess diverse clinical tissue [10]. Conventional histopathologic needle biopsy thus may bring utilities, and manifest a functional interplay with respect to facilitating a non-negligible false negative hPD-L1 detection [4]. Moreover, similar tumor progression, circulation, seeding as well as implantation of me- to the conventional detection of histopathologic hHER2 expression, tastatic cancer cells in carcinoma patients. invasive needle biopsy, routinely performed only once, is evidently not suitable for dynamically monitoring the expression of HER2 or PD-L1on 2. Materials and methods cancer cells. Recent progress in non-invasive liquid biopsy has made it feasible to periodically or constantly monitor dynamic expression of 2.1. Patients’ enrollment and specimen collection PD-L1 or HER2 on circulating tumor cells (CTCs) [11], which could serve as a surrogate marker available for frequent detections in cancer SE-iFISH was applied to comprehensively detect and characterize patients. PD-L1+ and Vimentin+ aneuploid CTCs and CTECs. A total of 16 ad- CTCs, cancer cells that are shed from primary or metastatic solid vanced NSCLC patients were enrolled. Fourteen patients failed first-line tumors into peripheral blood, are relevant to tumor metastasis and chemotherapy and received second-line anti-PD-1 nivolumab treat- + progression [12–14]. Aneuploid CD31 circulating tumor endothelial ment. Remaining 2 patients were subjected to first-line nivolumab + cells (CTECs) [15,16], are derived