Ex vivo expansion of circulating lung tumor cells based on one-step microfluidics-based immunomagnetic isolation

Circulating tumor cell-derived preclinical models: current status and future perspectives

Despite the advancements made in the diagnosis and treatment of cancer, the stages associated with metastasis remain largely incurable and represent the primary cause of cancer-related deaths. The dissemination of cancer is facilitated by circulating tumor cells (CTCs), which originate from the primary tumor or metastatic sites and enter the bloodstream, subsequently spreading to distant parts of the body. CTCs have garnered significant attention in research due to their accessibility in peripheral blood, despite their low abundance. They are being extensively studied to gain a deeper understanding of the mechanisms underlying cancer dissemination and to identify effective therapeutic strategies for advanced stages of the disease. Therefore, substantial efforts have been directed towards establishing and characterizing relevant experimental models derived from CTCs, aiming to provide relevant tools for research. In this review, we provide an overview of recent progress in the establishment of preclinical CTC-derived models, such as CTC-derived xenografts (CDX) and cell cultures, which show promise for the study of CTCs. We discuss the advantages and limitations of these models and conclude by summarizing the potential future use of CTCs and CTC-derived models in cancer treatment decisions and their utility as precision medicine tools.

Models to study CTCs and CTC culture methods

The vast majority of cancer-related deaths are due to the presence of disseminated disease. Understanding the metastatic process is key to achieving a reduction in cancer mortality. Particularly, there is a need to understand the molecular mechanisms that drive cancer metastasis, which will allow the identification of curative treatments for metastatic cancers. Liquid biopsies have arisen as a minimally invasive approach to gain insights into the biology of metastasis. Circulating tumour cells (CTCs), shed to the circulation from the primary tumour or metastatic lesions, are a key component of liquid biopsy. As metastatic precursors, CTCs hold the potential to unravel the mechanisms involved in metastasis formation as well as new therapeutic strategies for treating metastatic disease. However, the complex biology of CTCs together with their low frequency in circulation are factors hampering an in-depth mechanistic investigation of the metastatic process. To overcome these problems, CTC-derived models, including CTC-derived xenograft (CDX) and CTC-derived ex vivo cultures, in combination with more traditional in vivo models of metastasis, have emerged as powerful tools to investigate the biological features of CTCs facilitating cancer metastasis and uncover new therapeutic opportunities. In this chapter, we provide an up to date view of the diverse models used in different cancers to study the biology of CTCs, and of the methods developed for CTC culture and expansion, in vivo and ex vivo. We also report some of the main challenges and limitations that these models are facing.

Microfluidic-Assisted CTC Isolation and In Situ Monitoring Using Smart Magnetic Microgels

Capturing rare disease-associated biomarkers from body fluids can offer an early-stage diagnosis of different cancers. Circulating tumor cells (CTCs) are one of the major cancer biomarkers that provide insightful information about the cancer metastasis prognosis and disease progression. The most common clinical solutions for quantifying CTCs rely on the immunomagnetic separation of cells in whole blood. Microfluidic systems that perform magnetic particle separation have reported promising outcomes in this context, however, most of them suffer from limited efficiency due to the low magnetic force generated which is insufficient to trap cells in a defined position within microchannels. In this work, a novel method for making soft micromagnet patterns with optimized geometry and magnetic material is introduced. This technology is integrated into a bilayer microfluidic chip to localize an external magnetic field, consequently enhancing the capture efficiency (CE) of cancer cells labeled with the magnetic nano/hybrid microgels that are developed in the previous work. A combined numerical-experimental strategy is implemented to design the microfluidic device and optimize the capturing efficiency and to maximize the throughput. The proposed design enables high CE and purity of target cells and real-time time on-chip monitoring of their behavior. The strategy introduced in this paper offers a simple and low-cost yet robust opportunity for early-stage diagnosis and monitoring of cancer-associated biomarkers.

Near-Infrared Light-Responsive Size-Selective Lateral Flow Chip for Single-Cell Manipulation of Circulating Tumor Cells

Accurately obtaining information on the heterogeneity of CTCs at the single-cell level is a very challenging task that may facilitate cancer pathogenesis research and personalized therapy. However, commonly used multicellular population capture and release assays tend to lose effective information on heterogeneity and cannot accurately assess molecular-level studies and drug resistance assessment of CTCs in different stages of tumor metastasis. Herein, we designed a near-infrared (NIR) light-responsive microfluidic chip for biocompatible single-cell manipulation and study the heterogeneity of CTCs by a combination of the lateral flow microarray (LFM) chip and photothermal response system. First, immunomagnetic labeling and a gradient magnetic field were combined to distribute CTCs in different regions of the chip according to the content of surface markers. Subsequently, the LFM chip achieves high single-cell capture efficiency and purity (even as low as 5 CTCs per milliliter of blood) under the influence of lateral fluid and magnetic fields. Due to the rapid dissolution of the gelatin capture structure at 37 °C and the photothermal properties of gold nanorods, the captured single CTC cell can be recovered in large quantities at physiological temperature or released individually at a specific point by NIR. The multifunctional NIR-responsive LFM chip demonstrates excellent performance in capture and site release of CTCs with high viability, which provides a robust and versatile means for CTCs heterogeneity study at the single-cell level.

Electric field-assisted MnO2 nanomaterials for rapid capture and in situ delivery of circulating tumour cells

The heterogeneity of cancer has become a major obstacle to treatment, and the development of an efficient, fast, and accurate drug delivery system is even more urgent. In this work, we designed a device that integrated multiple functions of cell capture, in situ manipulation, and non-destructive release on a single device. With an applied electric field, an intelligent device based on MnO₂ nanomaterials was used to realize efficient and rapid capture of cancer cells in both patients' blood and artificial blood samples. This device could capture cancer cells with high efficiency (up to about 93%) and strong specificity in blood samples, the capture time was nearly 50 min faster than that of natural sedimentation, and reduce the effects on cells caused by long-time in vitro culture. In addition, Mn³⁺ on the surface of the MnO₂ substrate was reduced to Mn²⁺ by an electrochemical method, partial dissolution occurred, and then the captured cells were non-destructively released with rapid speed (about 8 s) and high efficiency (about 94 ± 2%). For in situ regulation, upon applying a pulse electric field, the captured cells were perforated nondestructively, and extracellular molecules could be delivered to the captured cells with well-performed dose and temporal controls. As a proof-of-concept application, we proved that the device could capture circulating tumor cells in peripheral blood faster and achieve in situ drug delivery. Finally, it can also quickly release circulating tumour cells for subsequent analysis, highlighting its accuracy, due to which it is widely used in medical treatment, basic tumor research and drug development.

Functional analysis of circulating tumour cells: the KEY to understand the biology of the metastatic cascade

Metastasis formation is the main cause of cancer-related death in patients with solid tumours. At the beginning of this process, cancer cells escape from the primary tumour to the blood circulation where they become circulating tumour cells (CTCs). Only a small subgroup of CTCs will survive during the harsh journey in the blood and colonise distant sites. The in-depth analysis of these metastasis-competent CTCs is very challenging because of their extremely low concentration in peripheral blood. So far, only few groups managed to expand in vitro and in vivo CTCs to be used as models for large-scale descriptive and functional analyses of CTCs. These models have shown already the high variability and complexity of the metastatic cascade in patients with cancer, and open a new avenue for the development of new diagnostic and therapeutic approaches.

Cell Lines of Circulating Tumor Cells: What Is Known and What Needs to Be Resolved

The importance of circulating tumor cells (CTC) is well recognized. However, the biological characteristics of CTC in the bloodstream have not yet been examined in detail, due to the limited number of CTC cell lines currently available. Thirty-nine CTC cell lines were reported by 2021. For successful cell culturing, these CTC cell lines were reviewed. Previous studies on short-term cultures of CTC also analyzed approaches for establishing the long-term culture of CTC. Negative selection, hypoxic conditions, three-dimensional conditions, and careful management are preferable for the long-term culture of CTC. However, the establishment of CTC cell lines is dependent on the specific characteristics of each cell type. Therefore, a method to establish CTC cell lines has not yet been developed. Further efforts are needed to resolve this issue.

Circulating Tumor Cells in Hepatocellular Carcinoma: A Comprehensive Review and Critical Appraisal

Hepatocellular carcinoma (HCC) is the fifth most common neoplasm and a major cause of cancer-related death worldwide. There is no ideal biomarker allowing early diagnosis of HCC and tumor surveillance in patients receiving therapy. Liquid biopsy, and particularly circulating tumor cells (CTCs), have emerged as a useful tool for diagnosis and monitoring therapeutic responses in different tumors. In the present manuscript, we evaluate the current evidence supporting the quantitative and qualitative assessment of CTCs as potential biomarkers of HCC, as well as technical aspects related to isolation, identification, and classification of CTCs. Although the dynamic assessment of CTCs in patients with HCC may aid the decision-making process, there are still many uncertainties and technical caveats to be solved before this methodology has a true impact on clinical practice guidelines. More studies are needed to identify the optimal combination of surface markers, to increase the efficiency of ex-vivo expansion of CTCs, or even to target CTCs as a potential therapeutic strategy to prevent HCC recurrence after surgery or to hamper tumor progression and extrahepatic spreading.

In Vitro Magnetic Techniques for Investigating Cancer Progression

Worldwide, there are currently around 18.1 million new cancer cases and 9.6 million cancer deaths yearly. Although cancer diagnosis and treatment has improved greatly in the past several decades, a complete understanding of the complex interactions between cancer cells and the tumor microenvironment during primary tumor growth and metastatic expansion is still lacking. Several aspects of the metastatic cascade require in vitro investigation. This is because in vitro work allows for a reduced number of variables and an ability to gather real-time data of cell responses to precise stimuli, decoupling the complex environment surrounding in vivo experimentation. Breakthroughs in our understanding of cancer biology and mechanics through in vitro assays can lead to better-designed ex vivo precision medicine platforms and clinical therapeutics. Multiple techniques have been developed to imitate cancer cells in their primary or metastatic environments, such as spheroids in suspension, microfluidic systems, 3D bioprinting, and hydrogel embedding. Recently, magnetic-based in vitro platforms have been developed to improve the reproducibility of the cell geometries created, precisely move magnetized cell aggregates or fabricated scaffolding, and incorporate static or dynamic loading into the cell or its culture environment. Here, we will review the latest magnetic techniques utilized in these in vitro environments to improve our understanding of cancer cell interactions throughout the various stages of the metastatic cascade.

Personalized Therapy and Liquid Biopsy-A Focus on Colorectal Cancer

(1) Background: Resistance mechanisms represent a barrier to anti-cancer therapies. Liquid biopsies would allow obtaining additional information in order to develop targeted therapies to thwart the resistance phenomena but also to follow in time real response to treatment and be able to adapt it the most quickly possible way in case of resistance. (2) Methods: herein we summarize the different liquid biopsies which are currently under research; we then review the literature and focalize on one of their potential roles: the theranostic one and especially in the cases of colorectal cancers. (3) Results: few studies targeting liquid biopsy as a potential tool to adapt cancer treatments are present in the literature and encompass few patients. (4) Conclusions: further research is needed to prove the efficiency of LB. Indeed, it seems a promising tool to guide treatment by targeting actionable mutations with detection of resistant mutations.

Jinfukang regulates integrin/Src pathway and anoikis mediating circulating lung cancer cells migration

ETHNOPHARMACOLOGICAL RELEVANCE

Metastasis is the main cause of death in lung cancer patients. Circulating tumor cells (CTCs) may be an important target of metastasis intervention. Previous studies have shown that Jinfukang could prevent the recurrence and metastasis of lung cancer, and we have established a circulating lung tumor cell line CTC-TJH-01. However, whether Jinfukang inhibition of lung cancer metastasis is related to CTCs is still unknown.

AIM OF THE STUDY

To further explore the mechanism of Jinfukang in anti-metastasis of lung cancer from the perspective of intervention of CTCs.

MATERIALS AND METHODS

CTC-TJH-01 and H1975 cells were treated with Jinfukang. Cell viability was detected by CCK8, and the cell apoptosis was detected by flow cytometry. Transwell was used to detected cell migration and invasion. Cell anoikis was detected by anoikis detection kit. Protein expression was analysis by Western blot.

RESULTS

Jinfukang could inhibit the proliferation, migration and invasion of CTC-TJH-01 and H1975 cells. Besides, Jinfukang could also induce anoikis in CTC-TJH-01 and H1975 cells. Analysis of the mRNA expression profile showed ECM-receptor interaction and focal adhesion were regulated by Jinfukang. Moreover, it was also find that Jinfukang significantly inhibited integrin/Src pathway in CTC-TJH-01 and H1975 cells. When suppress the expression of integrin with ATN-161, it could promote Jinfukang to inhibit migration and induce anoikis in CTC-TJH-01 and H1975 cells.

CONCLUSIONS

Our results indicate that the migration and invasion of CTCs are inhibited by Jinfukang, and the mechanism may involve the suppression of integrin/Src axis to induce anoikis. These data suggest that Jinfukang exerts anti-metastatic effects in lung cancer may through anoikis.

Proteomics analysis of tumor exosomes reveals vital pathways of Jinfukang inhibiting circulating tumor cells metastasis in lung cancer

ETHNOPHARMACOLOGICAL RELEVANCE

Jinfukang has long been used for the clinical treatment of lung cancer. Previous studies have shown that Jinfukang can induce the apoptosis of circulating tumor cells by intervening ROS-mediated DNA damage pathway. However, whether Jinfukang can inhibit the metastasis of circulating tumor cells and its mechanism are still unclear.

AIM OF THE STUDY

To further investigate the mechanism of Jinfukang in anti-metastasis of lung cancer from the perspective of intervention of tumor exosomes.

MATERIALS AND METHODS

The invadopodia formation was determined with immunofluorescence. Invasion and migration were detected using the Transwell assay. Ultracentrifugation was used to isolate exosomes. Exosomes were characterized by electron microscopy, nanoparticle tracking analysis and immunoblotting, and the protein profile was evaluated by proteomic analysis. The molecular functions, biological processes and signaling pathway enrichment analysis were performed using Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG). Key differentially expressed proteins were verified by Western blot.

RESULTS

Jinfukang can inhibit the expression of MMP14, cortactin, Tks5 and the formation of invadopodia of CTC-TJH-01 cells. Furthermore, Jinfukang can significantly inhibit the invasion and migration of CTC-TJH-01 cells. The diameter of exosomes extracted from the CTC-TJH-01 cells treated by Jinfukang was 30-100 nm, and the exosomal markers CD63, CD81 and TSG101 were expressed. We identified 680 deferentially expressed proteins. Gene oncology analysis indicated that exosomes were mostly derived from plasma membrane and mainly involved in protein localization and intracellular signaling. The ingenuity pathway analysis showed that the EGF pathway was significantly inhibited, whereas the GP6 signaling pathway was significantly activated. We also confirmed that Jinfukang inhibited the expression of EGF pathway-related proteins in CTC-TJH-01 cells. Besides, when EGF was used to activate EGF signaling pathway, the inhibition of Jinfukang on CTC cell metastasis was reversed.

CONCLUSION

Jinfukang inhibits the metastasis of CTC-TJH-01 cells through the EGF pathway.

Negative depletion mediated brightfield circulating tumour cell identification strategy on microparticle-based microfluidic chip

Background

The most convenient circulating tumor cells (CTCs) identification method is direct analysis of cells under bright field microscopy by which CTCs can be comprehensive studied based on morphology, phenotype or even cellular function. However, universal cell markers and a standard tumour cell map do not exist, thus limiting the clinical application of CTCs.

Results

This paper focuses on an automatic and convenient negative depletion strategy for circulating tumour cell identification under bright field microscopy. In this strategy, immune microparticles (IMPs) are applied to negatively label white blood cells rather than the tumour cells, such that tumour cells can be directly distinguished under brightfield of the microscopy. In this way, all of the heterogeneous tumour cells and their phenotype properties can be retained for further cancer-related studies. In addition, a wedge-shaped microfluidic chip is constructed for heterogeneous CTC pre-purification and enrichment by size, thus significantly decreasing the interference of haematological cells. Additionally, all cell treatments are processed automatically, and the tumour cells can be rapidly counted and distinguished via customized cell analytical software, showing high detection efficiency and automation. This IMPs based negative cell labelling strategy can also be combined with other classic cell identification methods, thus demonstrating its excellent compatibility.

Conclusion

This identification strategy features simple and harmless for tumour cells, as well as excellent accuracy and efficiency. And the low equipment demand and high automation level make it promise for extensive application in basic medical institutions.

Microfluidics for personalized drug screening of cancer

Resistance to targeted therapies is a major clinical challenge in cancer treatment. Despite technological advances, robust biomarkers or platforms predictive of treatment response are lacking owing to the inherent nature of complex genomic landscape of carcinoma. Nevertheless, recent efforts centred on performing direct drug screening on patient-derived cells through their ex vivo expansion and maintenance have enabled personalized stratification of treatment modalities. Microfluidics is one such technology that allows high-throughput drug screening through parallelization and automation using small-volume sample. In this review, we present recent microfluidic platforms that have been successfully applied for the maintenance and expansion of patient-derived tumor cells spanning diverse cancer types and sources (solid tumors or liquid biopsies (circulating tumor cells)) for personalized drug screening applications.

Circulating Tumour Cells in Lung Cancer

Circulating tumour cells (CTCs) constitute a potential tumour surrogate that could serve as "liquid biopsy" with the advantage to be a minimally invasive approach compared to traditional tissue biopsies. As CTCs are thought to be the source of metastatic lesions, their analysis represents a potential means of tracking cancer cells from the primary tumour en route to distant sites, thus providing valuable insights into the metastatic process. However, several problems, such as their rarity in the peripheral blood, the technical limitations of single-cell downstream analysis and their phenotypic variability, make CTC detection and molecular characterisation very challenging. Nevertheless, in the last decade, there has been an exponential increase of interest in the development of powerful cellular and molecular methodologies applied to CTCs. In this chapter, we focus on the recent advances of functional studies and molecular profiling of CTCs. We will also highlight the clinical relevance of CTC detection and enumeration, and discuss their potential as tumour biomarkers with special focus on lung cancer.

Electrochemical Detection of Circulating Tumor Cells Based on DNA Generated Electrochemical Current and Rolling Circle Amplification

Circulating tumor cells (CTCs) are important indicators for tumor diagnosis and tumor metastasis. However, the extremely low levels of CTCs in peripheral blood challenges the precise detection of CTCs. Herein, we report DNA generated electrochemical current combined with rolling circle amplification (RCA) as well as magnetic nanospheres for highly efficient magnetic capture and ultrasensitive detection of CTCs. The antiepithelial cell adhesion molecule (EpCAM) antibody-modified magnetic nanospheres were used to capture and enrich CTCs. The following binding of an aptamer onto the CTC surface and the subsequent RCA assembled a significant amount of DNA molecules onto the electrode. The reaction of the DNA molecules with molybdate can then form redox molybdophosphate and produce an electrochemical current. Using the breast cancer cell MCF-7 as a model, the sensor displays good performances toward detection of MCF-7 that was spiked into peripheral blood. The signal amplification strategy integrated with a magnetic nanosphere platform exhibits good performance in the efficient capture and detection of CTCs, which may find wide potential in cancer diagnostics and therapeutics.

Jingfukang induces anti-cancer activity through oxidative stress-mediated DNA damage in circulating human lung cancer cells

Background

Metastasis is the main cause of lung cancer death. As a seed of metastasis, circulating tumor cells are an important target for metastasis intervention. The traditional Chinese medicine, Jinfukang, has been clinically available for the treatment of non-small cell lung cancer (NSCLC). In this study, we investigated the action and underlying mechanisms of Jinfukang against circulating lung tumor cells.

Methods

The cell counting kit-8 (CCK-8), colony formation and cell cycle assays were used to study the cell proliferation ability. Flow cytometry was used to detect the apoptosis and the expression level of ROS and Caspase-3. Comet and TUNEL assays were used to detect DNA damage. DNA damage related pathway protein was detected by western blot.

Results

Jinfukang significantly inhibits the proliferation of CTC-TJH-01 cells by inducing G1 phase arrest and inhibits their colony formation in a dose-dependent manner. Moreover, Jinfukang induces apoptosis in CTC-TJH-01 cells through the ROS-mediated ATM/ATR-p53 pathway and DNA damage.

Conclusions

Our findings suggest that Jinfukang may be a potential drug for lung cancer metastasis.

Electronic supplementary material

The online version of this article (10.1186/s12906-019-2601-x) contains supplementary material, which is available to authorized users.

Rapid Formation of Arrayed Cells on an Electrode with Microwells by a Scanning Electrode Based on Positive Dielectrophoresis

We have developed a simple and rapid formation of a cell-based array on microwell array electrodes by an attractive force of positive dielectrophoresis (p-DEP), even after removing an upper disk electrode stick that was used as a counter electrode to the microwell array electrodes. The attractive force of p-DEP generated by the scanning of the disk electrode allows the formation of a cell-based array on all microwell arrays. We demonstrated an exploration of target cells spiked with a low ratio after removing the disk electrode.

Establishment and characterization of a patient-derived circulating lung tumor cell line in vitro and in vivo

BACKGROUND

Circulating tumor cells (CTCs) have been described as a population of cells that may seed metastasis, which is a reliable target for the prevention of metastases in lung cancer patients at the early stage. The culturing of CTCs in vitro can be used to study the mechanism of lung cancer metastasis and to screen antimetastasis drugs. This study aims to establish CTC cell line in vitro and explore the potential mechanism of its metastasis.

METHODS

A mixture of EpCAM- and EGFR-coated immunomagnetic microbeads in microfluidic Herringbone-Chip was used to capture CTCs. The CTCs, 95-D and A549 cells was evaluated by cell proliferation assays, clonal formation assays, migration assays and drug resistance. Flow cytometry and cytokine protein chip were used to detect the difference in phenotype and cytokine secretion between CTCs, 95-D and A549 cells. The NOD/SCID mice were used to study tumorigenicity, lung organ colonization and metastasis of CTCs. The H&E staining, immunohistochemistry and immunofluorescence assay were used to detect the pathological status of CTCs.

RESULTS

The number of EpCAM(+)/EGFR(+)/CK(+)/CD45(-) lung CTCs showed a weak negative correlation with clinical stages in patients with non-small cell lung cancer (NSCLC). In a phase IIa lung cancer patient, we successfully establish a permanent CTC cell line, named CTC-TJH-01. In vitro studies showed the CTC-TJH-01 cells were in the intermediate stage of epithelial to mesenchymal transition (EMT), had stem cell characteristics and were drug resistant. In vivo studies showed that CTC-TJH-01 cells can induce tumorigenesis, lung organ colonization and metastasis after xenografting in immunodeficient mice. In addition, the low expression level of CX3CL1 and high expression level of CXCL5 in the CTC-TJH-01 cells may be an important mechanism for their metastasis.

CONCLUSIONS

We successfully established a permanent CTC cell line with metastatic ability, which can be used to screen antimetastatic drugs and study the mechanism of lung cancer metastasis.

A Microwell-Assisted Multiaptamer Immunomagnetic Platform for Capture and Genetic Analysis of Circulating Tumor Cells

Detection of circulating tumor cells (CTCs) in peripheral blood is of paramount significance for cancer diagnosis, progress evaluation, and individualized therapy. However, the rareness and heterogeneity of CTCs introduces significant challenges in the capture of cancer cells as well as downstream genetic analysis. In this work, a microwell-assisted multiaptamer immunomagnetic platform (MMAIP) is proposed for highly efficient capture of CTCs with minimum influence of heterogeneity. Assisted by a microwell chip, the purity of CTCs is greatly improved, thus meeting the requirement of downstream gene analysis. This is, as far as is known, the first aptamer based platform enabling mutation analysis of the captured CTCs from cancer patients, which will contribute to the practical application of aptamers in clinics.

Exploring sialyl-Tn expression in microfluidic-isolated circulating tumour cells: A novel biomarker and an analytical tool for precision oncology applications

Circulating tumour cells (CTCs) originating from a primary tumour, lymph nodes and distant metastases hold great potential for liquid biopsies by providing a molecular fingerprint for disease dissemination and its temporal evolution through the course of disease management. CTC enumeration, classically defined on the basis of surface expression of Epithelial Cell Adhesion Molecule (EpCAM) and absence of the pan-leukocyte marker CD45, has been shown to correlate with clinical outcome. However, existing approaches introduce bias into the subsets of captured CTCs, which may exclude biologically and clinically relevant subpopulations. Here we explore the overexpression of the membrane protein O-glycan sialyl-Tn (STn) antigen in advanced bladder and colorectal tumours, but not in blood cells, to propose a novel CTC isolation technology. Using a size-based microfluidic device, we show that the majority (>90%) of CTCs isolated from the blood of patients with metastatic bladder and colorectal cancers express the STn antigen, supporting a link with metastasis. STn⁺ CTC counts were significantly higher than EpCAM-based detection in colorectal cancer, providing a more efficient cell-surface biomarker for CTC isolation. Exploring this concept, we constructed a glycan affinity-based microfluidic device for selective isolation of STn⁺ CTCs and propose an enzyme-based strategy for the recovery of viable cancer cells for downstream investigations. Finally, clinically relevant cancer biomarkers (transcripts and mutations) in bladder and colorectal tumours, were identified in cells isolated by microfluidics, confirming their malignant origin and highlighting the potential of this technology in the context of precision oncology.

An efficient method for CTCs screening with excellent operability by integrating Parsortix™-like cell separation chip and selective size amplification

In this article, an attempt for efficient screening of circulating tumor cells (CTCs) with excellent operability on microfluidic chips was reported. A Parsortix™-like cell separation chip was manufactured in our lab. This chip allowed lateral flow of fluid which increased the flow rate of blood. And, an air valve controlled injection pump was manufactured which allowed eight chips working simultaneously. This greatly facilitated the blood treatment process and saved time. As for the mechanism of screening circulating tumor cells, selective size amplification was utilized. By size amplification of cancer cells, both the hardness and the size of CTCs increased which differentiated them from blood cells. And the modification procedure of beads used for size amplification of cancer cells was optimized. Finally, by integrating the commercialized Parsortix™-like cell separation chip and selective size amplification, a practical method for screening circulating tumor cells was established.

Fluorometric detection of EGFR exon 19 deletion mutation in lung cancer cells using graphene oxide

Mutations in epidermal growth factor receptor (EGFR) are known as biomarkers that cause non-small cell lung cancer. Particularly, approximately 45% of non-small cell lung cancer patients possess a deletion in exon 19 of the EGFR gene. A less invasive method for detecting the EGFR mutation is required; thus, we developed a simple polymerase chain reaction (PCR)-based method for detecting EGFR exon 19 deletion by using a quencher-free fluorescent probe DNA and graphene oxide (GO). In the presence of the exon 19 deletion mutation, the fluorophore-labeled DNA probe was designed to be fully complementary to the mutant sequences. The fully annealed DNA probe was degraded by the 5' to 3' exonuclease activity of Taq DNA polymerase during PCR, releasing the fluorophore from the probe DNA. In contrast, a wild-type gene only allowed partial annealing of the probe DNA to the amplicon because of the absence of the deletion sequences, with Taq polymerase digestion releasing unannealed fragments of probe DNA. When GO was added to each reaction solution, starkly different fluorescence signals were obtained; enhanced fluorescence was observed because of the released fluorophore from the probe DNA that was not adsorbed onto GO, whereas fluorescence was quenched when the fragmented single-stranded probe DNA was readily adsorbed onto GO. Our method enabled the detection of as low as 49 pg of EGFR exon 19 deletion DNA with a detection limit of 0.1% when the mutant genomic DNA was mixed with wild-type DNA.

Circulating tumor cells in bladder cancer: Emerging technologies and clinical implications foreseeing precision oncology

CONTEXT

Circulating tumor cells (CTC) in peripheral blood of cancer patients provide an opportunity for real-time liquid biopsies capable of aiding early intervention, therapeutic decision, response to therapy, and prognostication. Nevertheless, the rare and potentially heterogeneous molecular nature of CTC has delayed the standardization of robust high-throughput capture/enrichment and characterization technologies.

OBJECTIVE

This review aims to systematize emerging solutions for CTC analysis in bladder cancer (BC), their opportunities and limitations, while providing key insights on specific technologic aspects that may ultimately guide molecular studies and clinical implementation.

EVIDENCE ACQUISITION

State-of-the-art screening for CTC technologies and clinical applications in BC was conducted in MEDLINE through PubMed.

EVIDENCE SYNTHESIS

From 200 records identified by the search query, 25 original studies and 1 meta-analysis met the full criteria for selection. A significant myriad of CTC technological platforms, including immunoaffinity, biophysical, and direct CTC detection by molecular methods have been presented. Despite their preliminary nature and irrespective of the applied technology, most studies concluded that CTC counts in peripheral blood correlated with metastasis. Associations with advanced tumor stage and grade and worst prognosis have been suggested. However, the unspecific nature, low sensitivity, and the lack of standardization of current methods still constitutes a major drawback. Moreover, few comprehensive molecular studies have been conducted on these poorly known class of malignant cells.

CONCLUSION

The current rationale supports the importance of moving the CTC field beyond proof of concept studies toward molecular-based solutions capable of improving disease management. The road has been paved for identification of highly specific CTC biomarkers and novel targeted approaches, foreseeing successful clinical applications.

Comprehensive Mutation and Copy Number Profiling in Archived Circulating Breast Cancer Tumor Cells Documents Heterogeneous Resistance Mechanisms

Addressing drug resistance is a core challenge in cancer research, but the degree of heterogeneity in resistance mechanisms in cancer is unclear. In this study, we conducted next-generation sequencing (NGS) of circulating tumor cells (CTC) from patients with advanced cancer to assess mechanisms of resistance to targeted therapy and reveal opportunities for precision medicine. Comparison of the genomic landscapes of CTCs and tissue metastases is complicated by challenges in comprehensive CTC genomic profiling and paired tissue acquisition, particularly in patients who progress after targeted therapy. Thus, we assessed by NGS somatic mutations and copy number alterations (CNA) in archived CTCs isolated from patients with metastatic breast cancer who were enrolled in concurrent clinical trials that collected and analyzed CTCs and metastatic tissues. In 76 individual and pooled informative CTCs from 12 patients, we observed 85% concordance in at least one or more prioritized somatic mutations and CNA between paired CTCs and tissue metastases. Potentially actionable genomic alterations were identified in tissue but not CTCs, and vice versa. CTC profiling identified diverse intra- and interpatient molecular mechanisms of endocrine therapy resistance, including loss of heterozygosity in individual CTCs. For example, in one patient, we observed CTCs that were either wild type for ESR1 (n = 5/32), harbored the known activating ESR1 p.Y537S mutation (n = 26/32), or harbored a novel ESR1 p.A569S (n = 1/32). ESR1 p.A569S was modestly activating in vitro, consistent with its presence as a minority circulating subclone. Our results demonstrate the feasibility and potential clinical utility of comprehensive profiling of archived fixed CTCs. Tissue and CTC genomic assessment are complementary, and precise combination therapies will likely be required for effective targeting in advanced breast cancer patients.Significance: These findings demonstrate the complementary nature of genomic profiling from paired tissue metastasis and circulating tumor cells from patients with metastatic breast cancer. Cancer Res; 78(4); 1110-22. ©2017 AACR.

Short term ex-vivo expansion of circulating head and neck tumour cells

Minimally invasive techniques are required for the identification of head and neck cancer (HNC) patients who are at an increased risk of metastasis, or are not responding to therapy. An approach utilised in other solid cancers is the identification and enumeration of circulating tumour cells (CTCs) in the peripheral blood of patients. Low numbers of CTCs has been a limiting factor in the HNC field to date. Here we present a methodology to expand HNC patient derived CTCs ex-vivo. As a proof of principle study, 25 advanced stage HNC patient bloods were enriched for circulating tumour cells through negative selection and cultured in 2D and 3D culture environments under hypoxic conditions (2% O₂, 5% CO₂). CTCs were detected in 14/25 (56%) of patients (ranging from 1–15 CTCs/5 mL blood). Short term CTC cultures were successfully generated in 7/25 advanced stage HNC patients (5/7 of these cultures were from HPV+ patients). Blood samples from which CTC culture was successful had higher CTC counts (p = 0.0002), and were predominantly from HPV+ patients (p = 0.007). This is, to our knowledge, the first pilot study to culture HNC CTCs ex-vivo. Further studies are warranted to determine the use of short term expansion in HNC and the role of HPV in promoting culture success.

Microfluidic Techniques for Analytes Concentration

Microfluidics has been undergoing fast development in the past two decades due to its promising applications in biotechnology, medicine, and chemistry. Towards these applications, enhancing concentration sensitivity and detection resolution are indispensable to meet the detection limits because of the dilute sample concentrations, ultra-small sample volumes and short detection lengths in microfluidic devices. A variety of microfluidic techniques for concentrating analytes have been developed. This article presents an overview of analyte concentration techniques in microfluidics. We focus on discussing the physical mechanism of each concentration technique with its representative advancements and applications. Finally, the article is concluded by highlighting and discussing advantages and disadvantages of the reviewed techniques.

The promise of circulating tumor cells for precision cancer therapy

The rapidly growing array of therapeutic options in cancer requires informative biomarkers to guide the rational selection and precision application of appropriate therapies. Circulating biomarkers such as circulating tumor cells have immense potential as noninvasive, serial 'liquid biopsies' that may be more representative of the complete spectrum of a patient's individual malignancy than spatially and temporally restricted tumor biopsies. In this review, we discuss the current state-of-the-art in the isolation and molecular characterization of circulating tumor cells as well as their utility in a wide range of clinical applications such as prognostics, treatment monitoring and identification of novel therapeutic targets and resistance mechanisms to enable real-time adjustments in the clinical management of cancer.

Single-Cell, Multiplexed Protein Detection of Rare Tumor Cells Based on a Beads-on-Barcode Antibody Microarray

Circulating tumor cells (CTCs) shed from tumor sites and represent the molecular characteristics of the tumor. Besides genetic and transcriptional characterization, it is important to profile a panel of proteins with single-cell precision for resolving CTCs' phenotype, organ-of-origin, and drug targets. We describe a new technology that enables profiling multiple protein markers of extraordinarily rare tumor cells at the single-cell level. This technology integrates a microchip consisting of 15000 60 pL-sized microwells and a novel beads-on-barcode antibody microarray (BOBarray). The BOBarray allows for multiplexed protein detection by assigning two independent identifiers (bead size and fluorescent color) of the beads to each protein. Four bead sizes (1.75, 3, 4.5, and 6 μm) and three colors (blue, green, and yellow) are utilized to encode up to 12 different proteins. The miniaturized BOBarray can fit an array of 60 pL-sized microwells that isolate single cells for cell lysis and the subsequent detection of protein markers. An enclosed 60 pL-sized microchamber defines a high concentration of proteins released from lysed single cells, leading to single-cell resolution of protein detection. The protein markers assayed in this study include organ-specific markers and drug targets that help to characterize the organ-of-origin and drug targets of isolated rare tumor cells from blood samples. This new approach enables handling a very small number of cells and achieves single-cell, multiplexed protein detection without loss of rare but clinically important tumor cells.