Heterogeneity Of Circulating Tumor Cells Research Articles

Engineered Leukocyte Biomimetic Colorimetric Sensor Enables High-Efficient Detection of Tumor Cells Based on Bioorthogonal Chemistry.

Accurate detection of heterogeneous circulating tumor cells (CTCs) is critical as they can make tumor cells more aggressive, drug-resistant, and metastasizing. Although the leukocyte membrane coating strategy is promising in meeting the challenge of detecting heterogeneous CTCs due to its inherent antiadhesive properties, it is still limited by the reduction or loss of expression of known markers. Bioorthogonal glycol-metabolic engineering is expected to break down this barrier by feeding the cells with sugar derivatives with a unique functional group to establish artificial targets on the surface of tumor cells. Herein, an engineered leukocyte biomimetic colorimetric sensor was accordingly fabricated for high-efficient detection of heterogeneous CTCs. Compared with conventional leukocyte membrane coating, the sensor could covalently bound to the heterogeneous CTCs models fed with Ac4ManNAz in vitro through the synergy of bioorthogonal chemistry and metabolic glycoengineering, ignoring the phenotypic changes of heterogeneous CTCs. Meanwhile, a sandwich structure composed of leukocyte biomimetic layer/CTCs/MoS2 nanosheet was formed for visual detection of HeLa cells as low as 10 cells mL-1. Overall, this approach can overcome the dependence of conventional cell membrane biomimetic technology on specific cell phenotypes and provide a new viewpoint to highly efficiently detect heterogeneous CTCs.

Dual targeting negative enrichment strategy for highly sensitive and purity detection of CTCs.

Circulating tumor cells (CTCs) have significant clinical value in early tumor detection, dynamic monitoring and immunotherapy. CTC detection stands out as a leading non-invasive approach for tumor diagnostics and therapeutics. However, the high heterogeneity of CTCs and the occurrence of epithelial-mesenchymal transition (EMT) during metastasis pose challenges to methods relying on EpCAM-positive enrichment. To address these limitations, a method based on negative enrichment of CTCs using specific leukocyte targets has been developed. In this study, aiming to overcome the low purity associated with immunomagnetic beads targeting solely the leukocyte common antigen CD45, we introduced CD66b-modified immunomagnetic beads. CD66b, a specific target for neutrophils with abundant residues, was chosen as a complementary approach. The process involved initial collection of nucleated cells from whole blood samples using density gradient centrifugation. Subsequently, magnetically labeled leukocytes were removed by magnetic field, enabling the capture of CTCs with higher sensitivity and purity while retaining their activity. Finally, we selected 20 clinical blood samples from patients with various cancers to validate the effectiveness of this strategy, providing a new generalized tool for the clinical detection of CTCs.

Greatly isolated heterogeneous circulating tumor cells using hybrid engineered cell membrane-camouflaged magnetic nanoparticles

BackgroundCirculating tumor cells (CTCs) are considered as a useful biomarker for early cancer diagnosis, which play a crucial role in metastatic process. Unfortunately, the tumor heterogeneity and extremely rare occurrence rate of CTCs among billions of interfering leukocytes seriously hamper the sensitivity and purity of CTCs isolation.MethodsTo address these, we firstly used microfluidic chips to detect the broad-spectrum of triple target combination biomarkers in CTCs of 10 types of cancer patients, including EpCAM, EGFR and Her2. Then, we constructed hybrid engineered cell membrane-camouflaged magnetic nanoparticles (HE-CM-MNs) for efficient capture of heterogeneous CTCs with high-purity, which was enabled by inheriting the recognition ability of HE-CM for various CTCs and reducing homologous cell interaction with leukocytes. Compared with single E-CM-MNs, HE-CM-MNs showed a significant improvement in the capture efficiency for a cell mixture, with an efficiency of 90%. And the capture efficiency of HE-CM-MNs toward 12 subpopulations of tumor cells was ranged from 70 to 85%. Furthermore, by using HE-CM-MNs, we successfully isolated heterogeneous CTCs with high purity from clinical blood samples. Finally, the captured CTCs by HE-CM-MNs could be used for gene mutation analysis.ConclusionsThis study demonstrated the promising potential of HE-CM-MNs for heterogeneous CTCs detection and downstream analysis.Graphical abstract

Circulating Tumor Cell Phenotype Detection and Epithelial-Mesenchymal Transition Tracking Based on Dual Biomarker Co-Recognition in an Integrated PDMS Chip.

Circulating tumor cells (CTCs) are widely considered as a reliable and promising class of markers in the field of liquid biopsy. As CTCs undergo epithelial-mesenchymal transition (EMT), phenotype detection of heterogeneous CTCs based on EMT markers is of great significance. In this report, an integrated analytical strategy that can simultaneously capture and differentially detect epithelial- and mesenchymal-expressed CTCs in bloods of non-small cell lung cancer (NSCLS) patients is proposed. First, a commercial biomimetic polycarbonate (PCTE) microfiltration membrane is employed as the capture interface for heterogenous CTCs. Meanwhile, differential detection of the captured CTCs is realized by preparing two distinct CdTe quantum dots (QDs) with red and green emissions, attached with EpCAM and Vimentin aptamers, respectively. For combined analysis, a polydimethylsiloxane (PDMS) chip with simple structure is designed, which integrates the membrane capture and QDs-based phenotype detection of CTCs. This chip not only implements the analysis of the number of CTCs down to 2 cellsmL-1, but enables EMT process tracking according to the specific signals of the two QDs. Finally, this method is successfully applied to inspect the correlations of numbers or proportions of heterogenous CTCs in 94 NSCLS patients with disease stage and whether there is distant metastasis.

Acoustic Enrichment of Heterogeneous Circulating Tumor Cells and Clusters from Metastatic Prostate Cancer Patients.

There are important unmet clinical needs to develop cell enrichment technologies to enable unbiased label-free isolation of both single cell and clusters of circulating tumor cells (CTCs) manifesting heterogeneous lineage specificity. Here, we report a pilot study based on the microfluidic acoustophoresis enrichment of CTCs using the CellSearch CTC assay as a reference modality. Acoustophoresis uses an ultrasonic standing wave field to separate cells based on biomechanical properties (size, density, and compressibility), resulting in inherently label-free and epitope-independent cell enrichment. Following red blood cell lysis and paraformaldehyde fixation, 6 mL of whole blood from 12 patients with metastatic prostate cancer and 20 healthy controls were processed with acoustophoresis and subsequent image cytometry. Acoustophoresis enabled enrichment and characterization of phenotypic CTCs (EpCAM+, Cytokeratin+, DAPI+, CD45-/CD66b-) in all patients with metastatic prostate cancer and detected CTC-clusters composed of only CTCs or heterogeneous aggregates of CTCs clustered with various types of white blood cells in 9 out of 12 patients. By contrast, CellSearch did not detect any CTC clusters, but detected comparable numbers of phenotypic CTCs as acoustophoresis, with trends of finding a higher number of CTCs using acoustophoresis. Our preliminary data indicate that acoustophoresis provides excellent possibilities to detect and characterize CTC clusters as a putative marker of metastatic disease and outcomes. Moreover, acoustophoresis enables the sensitive label-free enrichment of cells with epithelial phenotypes in blood and offers opportunities to detect and characterize CTCs undergoing epithelial-to-mesenchymal transitioning and lineage plasticity.

Circulating tumor cells shielded with extracellular vesicle-derived CD45 evade T cell attack to enable metastasis

Circulating tumor cells (CTCs) are precursors of distant metastasis in a subset of cancer patients. A better understanding of CTCs heterogeneity and how these CTCs survive during hematogenous dissemination could lay the foundation for therapeutic prevention of cancer metastasis. It remains elusive how CTCs evade immune surveillance and elimination by immune cells. In this study, we unequivocally identified a subpopulation of CTCs shielded with extracellular vesicle (EVs)-derived CD45 (termed as CD45+ CTCs) that resisted T cell attack. A higher percentage of CD45+ CTCs was found to be closely correlated with higher incidence of metastasis and worse prognosis in cancer patients. Moreover, CD45+ tumor cells orchestrated an immunosuppressive milieu and CD45+ CTCs exhibited remarkably stronger metastatic potential than CD45− CTCs in vivo. Mechanistically, CD45 expressing on tumor surfaces was shown to form intercellular CD45-CD45 homophilic interactions with CD45 on T cells, thereby preventing CD45 exclusion from TCR-pMHC synapse and leading to diminished TCR signaling transduction and suppressed immune response. Together, these results pointed to an underappreciated capability of EVs-derived CD45-dressed CTCs in immune evasion and metastasis, providing a rationale for targeting EVs-derived CD45 internalization by CTCs to prevent cancer metastasis.

Abstract 2771: Increased mtDNA copy number via EPOR signaling: A potential mechanism for metastatic dissemination in head and neck squamous cell carcinoma

Abstract Introduction: Head and Neck Squamous cell carcinoma (HNSCC) is characterized by high degree of invasion, locoregional metastasis, relapse which leads to overall poor prognosis. The molecular mechanism responsible for aggressiveness is poorly understood. A better understanding of molecular pathways involved shall precede the identification of newer diagnostic tools and therapeutic targets. We explored EPOR signaling pathway in Circulating tumor cells (CTCs) and HNSCC cell lines. Methods and Results: By using a validated in-house CTC isolation protocol, which addresses various drawbacks of currently available techniques and isolates CTCs suitable for various downstream molecular analysis, we isolated CTCs from HNSCC patients. The whole transcriptome analysis was performed from CTCs using ultra-low cell number RNA sequencing and corresponding primary tumors in 24 paired samples. We found a significant transcriptomic heterogeneity in CTCs, which are associated with overall disease outcome in HNSCC patients. To explore the plausible molecular pathways, we also identified 521 differentially expressed genes in CTCs with respect to primary tumors and various canonical pathways including oxidative phosphorylation, TCA cycle, cytokine-cytokine receptor interaction signaling, and ECM receptor interaction were enriched in CTC samples. Overexpression of erythropoietin receptor (EPOR) along with various genes encoded by mitochondrial genome and genes involved in maintenance of mtDNA in CTCs as compared to primary tumors was an important finding from our data. When analyzed in depth, there was a significant positive correlation between various genes involved in mtDNA maintenance (ABAT, NT5M) and encoded by mitochondrial genome (MT-ND1, MT-ND2, MT-ND4, MT-ND5, MT-ND6, MT-CO1, MT-CO2, MT-ATP6, MT-CYTB) with EPOR expression in our RNA seq data which is also substantiated by analyzing TCGA data. We confirmed these findings experimentally in HNSCC cell lines Cal 27 and FaDu. It was also observed that metastatic cell line FaDu has significantly higher mtDNA content as compared to non-metastatic cell line Cal 27, which was correlated with EPOR expression. Treatment with low dose Erythropoietin (0.1IU/mL) which a natural ligand for EPOR, enhanced mtDNA content in both the cell lines at low doses and boosted the metastatic capability while minimal effect on cell proliferation was observed. Conclusion: EPOR signaling might promote the metastatic ability of cancer cells and may act as a potential target for cancer dissemination and metastasis. Citation Format: Anshika Chauhan, Geeta S. Boora, Sahana Ghosh, Subrata K. Patra, Roshan K. Verma, Jaimanti Bakshi, Debajyoti Chatterjee, Radhika Srinivasan, Sushmita Ghoshal, Arindam Maitra, Arnab Pal. Increased mtDNA copy number via EPOR signaling: A potential mechanism for metastatic dissemination in head and neck squamous cell carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2771.

Abstract 2822: Heterogeneity of CD56+ circulating tumor cells and derived xenografts and response to treatment in small cell lung cancer

Abstract Small cell lung cancer (SCLC) represents the most aggressive subtype of lung cancer, comprising 15% of all cases. Clinical advancements in SCLC have been hindered by slow progress, attributed to significant tumor heterogeneity and early metastasis. The majority of patients experience relapse within a few months post-treatment, with 20% exhibiting chemorefractory characteristics. Recent identification of molecular subtypes in SCLC, dependent on predominant transcription factors ASCL1, NEUROD1, and POU2F3, has opened avenues for potential therapeutic targets. Preliminary studies on these transcriptomic subtypes suggest distinct therapeutic susceptibilities, and intriguingly, chemotherapy may induce alterations in transcriptomic subtypes.In the context of SCLC, diagnosis reveals a substantial presence of circulating tumor cells (CTCs) in the patient's bloodstream, which can be efficiently isolated. A previously published method allowed us to isolate CD56+ CTCs with high specificity (Ricordel et al., 2023). Our overarching hypothesis posits a connection between chemosensitivity and the heterogeneity of CTCs, leading us to seek bioclinical markers predictive of chemotherapy response. The clinical study, named CTC-CPC, is a monocentric prospective non-interventional investigation involving treatment-naïve SCLC patients. Blood samples were collected at the time of diagnosis for subsequent analysis. In our study, whole exome sequencing data from isolated CD56+ CTCs of 22 SCLC patients were analyzed. Various methods were employed to characterize inter-tumoral heterogeneity, including the identification of genetic alterations (SSMs and Indels), mutational signatures, and disrupted pathways. Prominently affected pathways included ECM organization, axon guidance, Rho GTPases, and Wnt signaling. Additionally, we unveiled substantial intra-tumoral heterogeneity using PhyloWGS, a technique for reconstructing subclonal composition and evolution from tumor sample sequencing. To further explore the impact of treatment, we aimed to clarify the expression of ASCL1, NEUROD1, and POU2F3 transcription markers in xenografts generated from patient CTCs at the time of diagnosis. Immunohistochemical studies were performed to identify potential changes in molecular subtypes at the protein level. The molecular subtypes of the four CDX we generated were characterized, revealing heterogeneity in the intratumoral expression of transcription markers for some xenografts. Subsequently, CTC-derived xenografts were subjected to chemotherapy, with observations indicating a change in the number of cells positive for ASCL1 and NEUROD1 after treatment, particularly in the CEM51.01 line treated with carboplatin, suggesting a potential modification in the tumor subtype induced by the treatment Citation Format: Laëtitia Martinetti, Pierre Montagne, Marlène Davilma, Ulrich Jarry, Aristotelis Chatziioannou, Marc Aubry, Charles Ricordel, Rémy Pedeux. Heterogeneity of CD56+ circulating tumor cells and derived xenografts and response to treatment in small cell lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2822.

Abstract 2304: Detection of early-disseminated cancer cells with deep learning-enabled holographic imaging

Abstract Recent research increasingly validates the early dissemination of tumor cells in peripheral blood during the nascent stages of cancer, often preceding clinical identification of the primary tumor. This emerging evidence emphasizes the potential of Circulating Tumor Cells (CTCs) as early indicators for cancer. Despite their significance, CTCs are exceptionally rare compared to normal blood cells, which presents a considerable challenge in detection, particularly during early stages of cancer. Traditional detection methods, such as those based on nucleated cell enrichment, antibody labeling and fluorescence imaging, encounter notable limitations when applied in the context of early detection. These limitations arise from the inherent heterogeneity of CTCs, and the multistep process involved in labeling and manual enumeration, compromising cell viability and resulting in cell loss. This loss becomes particularly problematic in the context of early cancer detection scenarios where the tumor burden is extremely low, and any cell loss can significantly impact assay sensitivity. To overcome these challenges, we propose an innovative CTC detection approach employing a deep learning framework combined with holographic imaging. This technique utilizes coherent light to generate holograms from cell samples, capturing detailed 3D morphological and optical properties of individual cells. We developed a custom convolutional neural network designed to facilitate high-throughput cell sorting in real-time. Trained on healthy blood samples and diverse cancer cell lines, the dataset consists of more than 50 million cellular holograms enhanced by proprietary Gaussian annotation and image augmentation strategies. Moreover, by combining the morphological signatures from holography with antigen signatures (e.g. HER2/ER/PR) in real-time, our model demonstrates the ability to detect less than 1 false positive per 1 million nucleated cells, highlighting its potential as a robust tool for targeted early-stage breast cancer detection. Our technology represents highly sensitive alternative to traditional screening methods, with the promise of enhancing patient outcomes. Citation Format: Nicholas Heller, Kevin Mallery, Nathaniel Bristow, Yash Travadi, Eng Hock Lee, Jiarong Hong. Detection of early-disseminated cancer cells with deep learning-enabled holographic imaging [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2304.

A Detachable Magnetic Nanodevice for the Efficient Capture and Subtype Identification of Circulating Tumor Cells

AbstractThe effective capture and accurate identification of heterogeneous circulating tumor cells (CTCs) aid in guiding clinical diagnosis and personalized treatment of tumors. Herein, a core‐satellite‐sized magnetic separable nanodevice (denoted as MS‐RI) is developed for the capture and subtype identification of heterogeneous CTCs by identifying the protein targets of CTCs in vitro and imaging intracellular nucleic acid targets of CTCs in situ. Upon the separation of CTCs by MS‐RI using aptamers as capture elements, the programmatically dissociated satellite particles aim to internalize into the cells for simultaneous profiling of microRNA‐21 and microRNA‐141. By virtue of the validated magnetic separation of the core structure, the high affinity of the aptamer, and the high sensitivity of the recognition imaging (RI) module, MS‐RI allows the isolation and subtyping of CTCs in clinical samples from breast cancer patients. This strategy of combining extracellular recognition and intracellular imaging pioneers a new paradigm for the capture and precision subtyping of heterogeneous CTCs.

Abstract 7504: Longitudinal multi-omics characterization of circulating tumor cells from ALK positive NSCLC patients

Abstract Introduction: Anaplastic lymphoma kinase positive non-small cell lung cancer (ALK+NSCLC) represents a distinct subtype of NSCLC characterized by oncogenic ALK gene mutations leading to ALK overexpression and activation in tumor cells. ALK+ NSCLC will frequently develop mutations during treatment, leading to nonresponse and eventually cancer relapse. Therefore, there is a critical need for sensitive technologies to monitor ALK+ NSCLC disease status in patients over time. To facilitate longitudinal monitoring, there has been a rapid evolution in diagnostic technologies leveraging circulating tumor cells (CTCs) as a liquid biopsy tool. CTCs can be collected non-invasively at various intervals throughout patient treatment. Moreover, they shed from solid tumors and disseminate into the bloodstream, which makes isolating CTCs a valuable source of genomic, transcriptomic, and proteomic insights pertaining to the primary tumor. In this study, we present a comprehensive workflow for conducting multi-omic analysis on CTCs derived from ALK+ NSCLC patients. Methods: Blood samples were collected from a cohort of ALK+ NSCLC patients, and CTCs were isolated using a high throughput, label free microfluidic device, Labyrinth. Enriched CTCs were immunofluorescently stained for cytokeratin, CD45, DAPI, epithelial cell adhesion molecule (EpCAM), and vimentin markers. Heterogeneous CTC populations with hybrid epithelial/mesenchymal (EM) phenotypes are reported. Fluorescence in situ hybridization (FISH) was performed on enriched CTC samples. DNA was extracted and sequenced using a 523 gene targeted sequencing panel. Single cell RNA-seq technology was performed in parallel on CTC samples to investigate the gene expression throughout treatment. Results: The median concentration of CTCs in the ALK+ NSCLC cohort (n=33) is 137 CTCs per ml of blood, and 64% of CTCs are in an EM hybrid state. In ALK+ NSCLC patients (n=3) with an average of 4.6 visits per sample, we observed a trend of decreasing CTC concentration for patients with partial response to the treatment. The presence of ALK fusion in ALK+ NSCLC patient’s CTC is confirmed by FISH. Oncogenic mutations (JAK1, SPEN, ERBB4, NTRK3) are observed in bulk CTC samples from two NSCLC patients. Single cell RNA sequencing was performed on three ALK+ NSCLC patients; 58, 199, and 700 potential CTCs were detected with positive cytokeratin expression and no white blood cell marker expression. Conclusions: This study examined the feasibility of using CTCs for studying and monitoring the clinical status of the ALK+ NSCLC patients as well as the genomic and transcriptomic signatures within their tumors. More patients will need to be processed in order to validate our workflow and reinforce our conclusions. Citation Format: Yuru Chen, Shamileh Fouladdel, Harrison Ball, Zhaoping Qin, Albert Liu, Xu Cheng, Liwei Bao, Habib Serhan, Bryce Vandenburg, Varun Kathawate, Larua Goo, Peter Ulintz, Nathan Merrill, Aaron Udager, Angel Qin, Sofia D. Merajver, Sunitha Nagrath. Longitudinal multi-omics characterization of circulating tumor cells from ALK positive NSCLC patients [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 7504.

A FACS-based novel isolation technique identifies heterogeneous CTCs in oral squamous cell carcinoma.

Isolating circulating tumour cells (CTCs) from the blood is challenging due to their low abundance and heterogeneity. Limitations of conventional CTC detection methods highlight the need for improved strategies to detect and isolate CTCs. Currently, the Food and Drug Administration (FDA)-approved CellSearch™ and other RUO techniques are not available in India. Therefore, we wanted to develop a flexible CTC detection/isolation technique that addresses the limitation(s) of currently available techniques and is suitable for various downstream applications. We developed a novel, efficient, user-friendly CTC isolation strategy combining density gradient centrifugation and immuno-magnetic hematogenous cell depletion with fluorescence-activated cell sorting (FACS)-based positive selection using multiple CTC-specific cell-surface markers. For FACS, a stringent gating strategy was optimised to exclude debris and doublets by side scatter/forward scatter (SSC/FSC) discriminator, remove dead cells by 4',6-diamidino-2-phenylindole (DAPI) staining, and eliminate non-specific fluorescence using a "dump" channel. APC-labelled anti-CD45mAB was used to gate remaining hematogenous cells, while multiple epithelial markers (EpCAM, EGFR, and Pan-Cytokeratin) and an epithelial-mesenchymal transition (EMT) marker (Vimentin) labelled with fluorescein isothiocyanate (FITC) were used to sort cancer cells. The technique was initially developed by spiking Cal 27 cancer cells into the blood of healthy donors and then validated in 95 biopsy-proven oral squamous cell carcinoma (OSCC) patients. CTCs isolated from patients were reconfirmed by Giemsa staining, immuno-staining, and whole transcriptome amplification (WTA), followed by qRT-PCR. In vitro culture and RNA sequencing (RNA-Seq) were also performed to confirm their suitability for various downstream applications. The mean detection efficiency for the Cal 27 tongue cancer cells spiked in the whole blood of healthy donors was 32.82% ± 12.71%. While ~75% of our patients (71/95) had detectable CTCs, the CTC positivity was independent of the TNM staging. The isolated potential cancer cells from OSCC patients were heterogeneous in size. They expressed different CTC-specific markers in various combinations as identified by qRT-PCR after WTA in different patients. Isolated CTCs were also found to be suitable for downstream applications like short-term CTC culture and RNA-Seq. We developed a sensitive, specific, flexible, and affordable CTC detection/isolation technique, which is scalable to larger patient cohorts, provides a snapshot of CTC heterogeneity, isolates live CTCs ready for downstream molecular analysis, and, most importantly, is suitable for developing countries.

A novel electrochemiluminescent cytosensor using 3D multivalent aptamer recognition and covalent organic frameworks-associated DNA walker for highly efficient capture and detection of rare CTCs

Circulating tumor cells (CTCs) are regarded as promising biomarkers for early clinical diagnosis, prognosis evaluation, and treatment monitoring. However, their limited abundance in peripheral blood and phenotypic heterogeneity resulting from epithelial-mesenchymal transition (EMT) present significant challenges for accurate detection of CTCs. Herein, we developed an ultrasensitive and highly specific cytosensor to address these limitations. Firstly, to overcome the EMT property of CTCs, we designed a novel 3D multivalent aptamer recognition strategy (MARS), which not only contributed to highly efficient capture of heterogeneous CTCs, but also guaranteed detection sensitivity of the developed cytosensor. Meanwhile, we integrated an exonuclease III (Exo III)-mediated DNA walking signal amplification strategy into the electrochemiluminescence (ECL) cytosensor, enhancing its sensitivity in detecting rare CTCs. Furthermore, in combination with the excellent ECL performance of the luminescent nanomaterials (Au@COF-LZU1@Ru), the cytosensor exhibited a wide detection range from 8 to 1 × 105 cells/mL with a detection limit as low as 2 cells/mL. The analytical performance of the constructed cytosensor was validated through real sample analysis (AUC = 0.97), demonstrating its potential for clinical applications. The novel cytosensor offers an effective and reliable tool for the detection of rare CTCs, thereby paving the way for improved clinical significance.

Enumeration and Molecular Characterization of Circulating Tumor Cell Using an Epithelial Cell Adhesion Molecule/Vimentin/Epidermal Growth Factor Receptor Joint Capture System in Lung Cancer.

Detection rate and isolation yield of circulating tumor cells (CTCs) are low in lung cancer with approaches due to CTC invasiveness and heterogeneity. In this study, on the basis of the epithelial cell adhesion molecule (EpCAM) phenotype, markers of vimentin and epidermal growth factor receptor (EGFR) phenotype were added to jointly construct a precise and efficient CTC capture system for capture of lung cancer CTCs. A CTC capture system combined with EpCAM lipid magnetic bead (Ep-LMB)/vimentin lipid magnetic bead (Vi-LMB)/EGFR lipid magnetic bead (EG-LMB) was constructed, and its performance was tested. The amount of CTC captured in the blood of patients with lung cancer was detected by immunofluorescence identification and analyzed for clinical relevance. The constructed CTC capture system has low cytotoxicity. The capture efficiency of lung cancer cells in phosphate belanced solution (PBS) system was 95.48%. The capture efficiency in the blood simulation system is 94.55%. The average number of CTCs in the blood of patients with lung cancer was 9.73/2 mL. The quantity distribution of CTCs is significantly correlated with tumor staging and metastasis. The area under the curve (AUC) of CTCs for the diagnosis of lung cancer was 0.9994 (95% CI = 0.9981-1.000, P < .0001). The cutoff value was 4.5/2 mL. The sensitivity was 99.39%, and the specificity was 96.88%. The EpCAM/vimentin/EGFR combined capture system has feasibility and high sensitivity in the detection of lung cancer CTC typing, which can be used as an auxiliary diagnostic indicator for lung cancer and is expected to promote the clinical application of CTCs.

Generally applicable circulating tumor cell enrichment and identification through a membrane glycoprotein-targeting strategy combining magnetic isolation and biological orthogonality labeling.

Although the importance of circulating tumor cells (CTCs) has been widely recognized, it is still a challenge to realize high-efficiency and accurate enrichment and identification of highly heterogeneous CTCs derived from various types of tumors in complex cancer processes. Currently, the most widely used methods follow the general idea of sequential immunoaffinitive capture and immunostaining to achieve the abovementioned goal. However, different organ/tissue origins as well as the inherent heterogeneity of CTCs would lead to the missed detection of certain CTC subtypes using such methods. Further, immunocytochemistry (ICC) immunostaining disrupts the physiological structure of cells, severely limiting the detection and application scenarios that require the participation of live cells. To address these limitations, we have developed a generally applicable strategy for the isolation and labeling of CTCs. This strategy focuses on targeting the universal characteristics of all tumor cells, specifically the abnormally expressed cell membrane glycoproteins, such as the transferrin receptor and sialic acid. Strategically, transferrin-functionalized magnetic beads (TMBs) were applied to enrich CTCs, and azide-based bioorthogonal chemistry was employed to label target CTCs. Accordingly, the membrane glycoprotein-targeting strategy achieved unbiased enrichment and labeling of broad-spectrum CTCs that were both epithelial and non-epithelial phenotypic populations with varied organ/tissue origins (MCF-7, HepG2, A549, Jurkat, and B16), with a capture efficiency of >95% and a detection limit as low as 5 cells per mL in artificial blood. In particular, our developed strategy displayed excellent specificity, and the CTCs under capture and fluorescence labelling remained with good viability and could be further cultivated and analyzed. Finally, the membrane glycoprotein-targeting strategy successfully detected and identified 33-223 CTCs from 1 mL patient blood samples.

Abstract LB_B05: Mapping therapy resistant phenotypes in SCLC liquid biopsies with single-cell proteomics at a personalized level

Abstract Small-cell lung cancer (SCLC) accounts for ~15% cases of all lung cancer cases and is characterized by aggressive growth and dismal prognosis. Although patients initially respond favorably to platinum and immune checkpoint blockade therapy, most develop therapy resistance and relapse within 1 year. Leveraging liquid biopsies and circulating tumor cells (CTCs) for evaluating SCLC status is regarded as a promising approach especially in SCLC where biopsies are scarce. SCLC CTC numbers are higher compared to other cancers, presenting a unique opportunity to utilize them for assessing SCLC therapy response and resistance and identifying new targetable markers. In this study we leverage mass cytometry (i.e., CyTOF), a multiplex cytometric approach that enables interrogation of 30-50 protein markers per single cell, allowing us to identify and analyze a significant number of CTCs and their heterogeneous expression profiles. Our goal was to utilize CyTOF to help us map changes in CTC expression profiles in the treatment naïve and relapsed setting and thus be able to assess therapy response and resistance at a personalized level. To achieve this, we optimized a CyTOF antibody panel by using SCLC cell lines and blood specimens from healthy donors and SCLC patients. We show that by using this approach, we are able to identify and phenotype SCLC CTCs by using the combination of CD45 (negative expression) and CD56 positive expression with further validation achieved by TTF1 and SCLC subtype transcription factor expression (e.g. NEUROD1, POU2F3). This approach avoids enriching for specific CTC epithelial phenotypes that express surface markers that fluctuate during epithelial-mesenchymal transition (EMT) (e.g. EpCAM, a common marker for isolating CTCs). We also evaluated markers that describe immune suppression activity (PD-L1), EMT status (E-Cadherin, Vimentin, MUC1, Slug), as well as markers that can be therapeutically targeted/are indicative of resistance (e.g., p-YAP). For parallel immune profiling we assessed among others CD8/CD4 (T-cytotoxic/T-helpers respectively) and CD11b and HLA-DR (Myeloid-derived suppressor cells, MDSCs) expression. We found that p-YAP and MUC1 are significantly increased in CTCs detected in blood specimens from SCLC relapsed patients compared to treatment naïve patients. Both YAP and MUC1 have been shown to be play a role in therapy resistance and YAP inhibition is considered a promising therapeutic target. Our analysis also showed a significant increase of MDSC (CD33+CD11b+HLA-DR-) percentages and a decrease in the CD4/CD8 T cell ratio in the relapsed setting. Finally, when we used PHENOSTAMP, a previously developed reference EMT map for assessing EMT phenotypes in lung cancer clinical specimens at a personalized level, we observed an increase of EMT heterogeneity in CTCs in relapsed patients. Our data highlight the translational power of our approach in tracking therapy resistant cells during therapy directly in SCLC patient liquid biopsies towards assessing therapy resistance at a personalized level. Citation Format: Sayantan Bhattacharyya, Catherine A Stewart, Ashley M Victorian, Shafqat F Ehsan, Ester F Lujan, Alberto Duarte, John V Heymach, Jing Wang, Lauren A Byers, Loukia G Karacosta. Mapping therapy resistant phenotypes in SCLC liquid biopsies with single-cell proteomics at a personalized level [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2023 Oct 11-15; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2023;22(12 Suppl):Abstract nr LB_B05.

Advances in the role of circulating tumor cell heterogeneity in metastatic small cell lung cancer

AbstractSmall cell lung cancer (SCLC), a highly aggressive malignancy, is rapidly at an extensive stage once diagnosed and is one of the leading causes of death from malignancy. In the past decade, the treatment of SCLC has largely remained unchanged, and chemotherapy remains the cornerstone of SCLC treatment. The therapeutic value of adding immune checkpoint inhibitors to chemotherapy for SCLC is low, and only a few SCLC patients have shown a response to immune checkpoint inhibitors. Circulating tumor cells (CTCs) are tumor cells shed from solid tumor masses into the peripheral circulation and are key to tumor metastasis. Single‐cell sequencing has revealed that the genetic profiles of individual CTCs are highly heterogeneous and contribute to the poor outcome and prognosis of SCLC patients. Theoretically, phenotypic analysis of CTCs may be able to predict the diagnostic significance of new potential targets for metastatic tumors. In this paper, we will discuss in depth the heterogeneity of CTCs in SCLC and the value of CTCs for the diagnosis and prognosis of SCLC and as relevant tumor markers in metastatic SCLC.

Recent Progress in Enhanced Cancer Diagnosis, Prognosis, and Monitoring Using a Combined Analysis of the Number of Circulating Tumor Cells (CTCs) and Other Clinical Parameters.

Analysis of circulating tumor cells (CTCs) holds promise to diagnose cancer or monitor its development. Among the methods, counting CTC numbers in blood samples could be the simplest way to implement it. Nevertheless, its clinical utility has not yet been fully accepted. The reasons could be due to the rarity and heterogeneity of CTCs in blood samples that could lead to misleading results from assays only based on single CTC counts. To address this issue, a feasible direction is to combine the CTC counts with other clinical data for analysis. Recent studies have demonstrated the use of this new strategy for early detection and prognosis evaluation of cancers, or even for the distinguishment of cancers with different stages. Overall, this approach could pave a new path to improve the technical problems in the clinical applications of CTC counting techniques. In this review, the information relevant to CTCs, including their characteristics, clinical use of CTC counting, and technologies for CTC enrichment, were first introduced. This was followed by discussing the challenges and new perspectives of CTC counting techniques for clinical applications. Finally, the advantages and the recent progress in combining CTC counts with other clinical parameters for clinical applications have been discussed.

A microfluidic device for enhanced capture and high activity release of heterogeneous CTCs from whole blood

Circulating tumor cells (CTCs) are tumor cells that spontaneously detach from the primary focus, and early detection and characterization of CTCs is vital for cancer diagnosis and appropriate treatment. Current methods commonly use EpCAM to capture CTCs, but this results in a loss of information on other CTC subsets (EpCAM-negative cells) due to the heterogeneity of CTCs. Here, we report a novel microfluidic device that integrates the capture and release of heterogeneous CTCs directly from whole blood. A spiral chip was designed for the separation of differently sized cells, and larger CTCs were effectively separated from smaller blood cells with a 98% recovery rate. CD146-containing magnetic beads were used to complement the EpCAM-based CTC capture methods, and the capture efficiency of Fe3O4@Gelatin@CD146/EpCAM increased by 20% over Fe3O4@Gelatin@EpCAM. Finally, MMP-9 was employed to release CTCs with high efficiency and less damage by degrading gelatins on the surface of Fe3O4. The established method was successfully applied to CTC capture and release in a simulated patient's whole blood. The developed method achieved enhanced capture and high activity release of heterogeneous CTCs with less interference by blood cells, which contributes to the early detection and clinical downstream analysis of CTCs.

Establishment of a cascaded microfluidic single cell analysis system for molecular and functional heterogeneity analysis of circulating tumor cells

Single cell heterogeneity analysis of circulating tumor cells (CTCs) is expected to reveal important tumor biological information for the evaluation and prediction of tumor stage and metastatic progression. Although various methods have been proposed to isolate and detect CTCs, consecutive CTCs sorting and in-situ multi-dimensional heterogeneity analysis in a cascaded system remain challenging. Here, a cascaded microfluidic chip was constructed, successively integrating a spiral structure for size-based removal of blood cells and a single cell array structure for the subsequent capture of CTCs, complementing the advantages of high throughput and high separation purity for both structures. Importantly, the molecular and functional heterogeneity analysis of CTCs can be in-situ realized and real-time observed at the single-cell level. Using this system, we captured CTCs and situ-analyzed the heterogeneity of single CTCs from different types of cancer patients, finding that mesenchymal phenotype is present in more CTCs at the advanced stage, and CTCs show active motility and division ability in metastatic patients. Therefore, the cascaded microfluidic chip offers an effective strategy for studying the molecular and functional heterogeneity of single CTCs, providing critical information for the evaluation of tumor progression and metastasis.