Rapid translation of circulating tumor cell biomarkers into clinical practice: technology development, clinical needs and regulatory requirements

Development of a multiplex assay to assess activated p300/CBP in circulating prostate tumor cells

Reduced SIRT2 deacetylation and increased p300 acetylation activity leads to a concerted mechanism of hyperacetylation at specific histone lysine sites (H3K9, H3K14, and H3K18) in castration-resistant prostate cancer (CRPC). We examined whether circulating tumor cells (CTCs) identify patients with altered p300/CBP acetylation. CTCs were isolated from 13 advanced PC patients using Exclusion-based Sample Preparation (ESP) technology. Bound cells underwent immunofluorescent staining for histone modifying enzymes (HMEs) of interest and image capture with NIS-Elements software. Using the cBioPortal PCF/SU2C dataset, the response of CRPC to androgen receptor signaling inhibitors (ARSI) was analyzed in 50 subjects. Staining optimization and specificity revealed clear expression of acetyl-p300, acetyl-H3K18, and SIRT2 on CTCs (CK positive, CD45 negative cells). Exposure to A-485, a selective p300/CBP catalytic inhibitor, reduced p300 and H3K18 acetylation. In CRPC patients, a-p300 strongly correlated with its target acetylated H3k18 (Pearson's R = 0.61), and SIRT2 expression showed robust negative correlation with a-H3k18 (R = -0.60). A subgroup of CRPC patients (6/11; 55%) demonstrated consistent upregulation of acetylation based on these markers. To examine the clinical impact of upregulation of the CBP/p300 axis, CRPC patients with reduced deacetylase SIRT2 expression demonstrate shorter response times to ARSI therapy (5.9 vs. 12 mo; p = 0.03). A subset of CRPC patients demonstrate increased p300/CBP activity based on a novel CTC biomarker assay. With further development, this biomarker suite may be used to identify candidates for CBP/p300 acetylation inhibitors in clinical development.

Measurement of Exhaled Nitric Oxide in 456 Lung Cancer Patients Using a Ringdown FENO Analyzer

The objective of this study was to investigate the clinical value of exhaled nitric oxide (NO) for diagnosing lung cancer patients by using a relatively large sample. An online and near-real-time ringdown exhaled NO analyzer calibrated by an electrochemical sensor at clinical was used for breath analysis. A total of 740 breath samples from 284 healthy control subjects (H) and 456 lung cancer patients (LC) were collected. The recorded data included exhaled NO, medications taken within the last half month, demographics, fasting status and smoking status. The LC had a significantly higher level of exhaled NO than the H (H: 21.0 ± 12.1 ppb vs. LC: 34.1 ± 17.2 ppb). The area under the receiver operating characteristic curve for exhaled NO predicting LC and H was 0.728 (sensitivity was 0.798; specificity was 0.55). There was no significant difference in exhaled NO level between groups divided by different types of LC, tumor node metastasis (TNM) stage, sex, smoking status, age, body mass index (BMI) or fasting status. Exhaled NO level alone is not a useful clinical tool for identifying lung cancer, but it should be considered when developing a diagnosis model of lung cancer by using breath analysis.

OPENchip: an on-chip in situ molecular profiling platform for gene expression analysis and oncogenic mutation detection in single circulating tumour cells

Liquid biopsy holds promise towards practical implementation of personalized theranostics of cancer. In particular, circulating tumour cells (CTCs) can provide clinically actionable information that can be directly linked to prognosis or therapy decisions. In this study, gene expression patterns and genetic mutations in single CTCs are simultaneously analysed by strategically combining microfluidic technology and in situ molecular profiling technique. Towards this, the development and demonstration of the OPENchip (On-chip Post-processing ENabling chip) platform for single CTC analysis by epithelial CTC enrichment and subsequent in situ molecular profiling is reported. For in situ molecular profiling, padlock probes that identify specific desired targets to examine biomarkers of clinical relevance in cancer diagnostics were designed and used to create libraries of rolling circle amplification products. We characterize the OPENchip in terms of its capture efficiency and capture purity, and validate the probe design using different cell lines. By integrating the obtained results, molecular analyses of CTCs from metastatic breast cancer (HER2 (ERBB2) gene expression and PIK3CA mutations) and metastatic pancreatic cancer (KRAS gene mutations) patients were demonstrated without any off-chip processes. The results substantiate the potential implementation of early molecular detection of cancer through sequencing-free liquid biopsy.

Breath analysis of cancer in the present and the future

Most of the currently used diagnostics for cancerous diseases have yet to meet the standards of screening, as they are insufficiently accurate and/or invasive and risky. In this review, we describe the rationale, the progress made to date, and the potential of analysing the exhaled volatile organic compounds as a pathway for enabling early diagnosis of cancer and, therefore, for achieving better clinical prognosis and survival rates. The review highlights the major advancements made in this field, from fundamentals, up to translational phases and clinical trials, with a special emphasis on sensing platforms based on nanomaterials. The prospects for breath analysis in early cancerous disease are presented and discussed.

Distribution of circulating tumor cell phenotype in early cervical cancer

Background and objective: Circulating tumor cells (CTCs) can be classified into three phenotypes based on epithelial-to-mesenchymal transition (EMT) markers, including epithelial CTCs, mesenchymal CTCs, and mixed phenotypic CTCs. This study is aimed to analyze the correlation between CTC phenotypes and the clinicopathological features of patients with early cervical cancer.

Methods: Peripheral blood samples were obtained from 90 patients with early cervical cancer. CTCs were isolated and classified. The correlations of CTC counts and CTC phenotypes with clinicopathological features of patients were analyzed.

Results: The positivity rate for CTCs in patients with stage I-IIA cervical cancer was 90%. An increased CTC number was observed in patients with FIGO stage II, pelvic lymph node metastasis, and lymphovascular involvement. There were 38.89% epithelial CTCs, 23.33% mesenchymal CTCs, and 14.44% mixed phenotypic CTCs, Mesenchymal CTCs were more common in patients with FIGO stage II, pelvic lymph node metastasis, lymphovascular involvement, and deep stromal invasion.

Conclusion: CTCs with mesenchymal phenotypes are closely related to pelvic lymph node metastasis and lymphatic vascular invasion in stage I-IIA cervical cancer. Detection of circulating tumor cell phenotypes is helpful for the early diagnosis of cervical cancer micro-metastasis and for the assessment of disease status.

Development and translation of novel therapeutics targeting tumor-associated macrophages

Tumor-associated macrophages (TAMs) regulate an array of tumor functions and have critical roles in both the progression and the eradication of cancer. Numerous therapies targeting TAMs are under development in cancer and many have demonstrated success at the preclinical and clinical levels. Most of these therapies fall within 3 main categories: systemic depletion of TAMs, inhibition of TAM recruitment and polarization, and promoting the antitumor functions of TAMs. In this article, the rationale behind these various therapies and approaches is reviewed along with supporting preclinical and clinical data.

Versatile exclusion-based sample preparation platform for integrated rare cell isolation and analyte extraction

Rare cell populations provide a patient-centric tool to monitor disease treatment, response, and resistance. However, understanding rare cells is a complex problem, which requires cell isolation/purification and downstream molecular interrogation - processes challenged by non-target populations, which vary patient-to-patient and change with disease. As such, cell isolation platforms must be amenable to a range of sample types while maintaining high efficiency and purity. The multiplexed technology for automated extraction (mTAE) is a versatile magnetic bead-based isolation platform that facilitates positive, negative, and combinatorial selection with integrated protein staining and nucleic acid isolation. mTAE is validated by isolating circulating tumor cells (CTCs) - a model rare cell population - from breast and prostate cancer patient samples. Negative selection yielded high efficiency capture of CTCs while positive selection yielded higher purity with an average of only 95 contaminant cells captured per milliliter of processed whole blood. With combinatorial selection, an overall increase in capture efficiency was observed, highlighting the potential significance of integrating multiple capture approaches on a single platform. Following capture (and staining), on platform nucleic acid extraction enabled the detection of androgen receptor-related transcripts from CTCs isolated from prostate cancer patients. The flexibility (e.g. negative, positive, combinatorial selection) and capabilities (e.g. isolation, protein staining, and nucleic acid extraction) of mTAE enable users to freely interrogate specific cell populations, a capability required to understand the potential of emerging rare cell populations and readily adapt to the heterogeneity presented across clinical samples.

Methods for the evaluation of biomarkers in patients with kidney and liver diseases: multicentre research programme including ELUCIDATE RCT

Background

Protein biomarkers with associations with the activity and outcomes of diseases are being identified by modern proteomic technologies. They may be simple, accessible, cheap and safe tests that can inform diagnosis, prognosis, treatment selection, monitoring of disease activity and therapy and may substitute for complex, invasive and expensive tests. However, their potential is not yet being realised.

Design and methods

The study consisted of three workstreams to create a framework for research: workstream 1, methodology – to define current practice and explore methodology innovations for biomarkers for monitoring disease; workstream 2, clinical translation – to create a framework of research practice, high-quality samples and related clinical data to evaluate the validity and clinical utility of protein biomarkers; and workstream 3, the ELF to Uncover Cirrhosis as an Indication for Diagnosis and Action for Treatable Event (ELUCIDATE) randomised controlled trial (RCT) – an exemplar RCT of an established test, the ADVIA Centaur® Enhanced Liver Fibrosis (ELF) test (Siemens Healthcare Diagnostics Ltd, Camberley, UK) [consisting of a panel of three markers – (1) serum hyaluronic acid, (2) amino-terminal propeptide of type III procollagen and (3) tissue inhibitor of metalloproteinase 1], for liver cirrhosis to determine its impact on diagnostic timing and the management of cirrhosis and the process of care and improving outcomes.

Results

The methodology workstream evaluated the quality of recommendations for using prostate-specific antigen to monitor patients, systematically reviewed RCTs of monitoring strategies and reviewed the monitoring biomarker literature and how monitoring can have an impact on outcomes. Simulation studies were conducted to evaluate monitoring and improve the merits of health care. The monitoring biomarker literature is modest and robust conclusions are infrequent. We recommend improvements in research practice. Patients strongly endorsed the need for robust and conclusive research in this area. The clinical translation workstream focused on analytical and clinical validity. Cohorts were established for renal cell carcinoma (RCC) and renal transplantation (RT), with samples and patient data from multiple centres, as a rapid-access resource to evaluate the validity of biomarkers. Candidate biomarkers for RCC and RT were identified from the literature and their quality was evaluated and selected biomarkers were prioritised. The duration of follow-up was a limitation but biomarkers were identified that may be taken forward for clinical utility. In the third workstream, the ELUCIDATE trial registered 1303 patients and randomised 878 patients out of a target of 1000. The trial started late and recruited slowly initially but ultimately recruited with good statistical power to answer the key questions. ELF monitoring altered the patient process of care and may show benefits from the early introduction of interventions with further follow-up. The ELUCIDATE trial was an ‘exemplar’ trial that has demonstrated the challenges of evaluating biomarker strategies in ‘end-to-end’ RCTs and will inform future study designs.

Conclusions

The limitations in the programme were principally that, during the collection and curation of the cohorts of patients with RCC and RT, the pace of discovery of new biomarkers in commercial and non-commercial research was slower than anticipated and so conclusive evaluations using the cohorts are few; however, access to the cohorts will be sustained for future new biomarkers. The ELUCIDATE trial was slow to start and recruit to, with a late surge of recruitment, and so final conclusions about the impact of the ELF test on long-term outcomes await further follow-up. The findings from the three workstreams were used to synthesise a strategy and framework for future biomarker evaluations incorporating innovations in study design, health economics and health informatics.

Trial registration

Current Controlled Trials ISRCTN74815110, UKCRN ID 9954 and UKCRN ID 11930.

Funding

This project was funded by the NIHR Programme Grants for Applied Research programme and will be published in full inProgramme Grants for Applied Research; Vol. 6, No. 3. See the NIHR Journals Library website for further project information.

Circulating tumor cells in clinical research and monitoring patients with colorectal cancer

Colorectal cancer remains a frequent disease to which screening and target therapy exist, but despite this is still marked by a high mortality rate. Even though radical surgery may be performed in many cases, patients relapse with metastatic disease. Circulating tumor cells were incriminated for tumor recurrence, that's why vigorous research started on their field. Owning prognostic and predictive value, it was revealed their usefulness in disease monitoring. Moreover, they may serve as liquid biopsies for genetic tests in cases where tissue biopsy is contraindicated or cannot be performed. In spite of these advantages, they were not included in clinical guidelines, despite CellSearch and many other detection methods were developed to ease the identification of circulating tumor cells. This review highlights the implication of circulating tumor cells in metastasis cascade, intrinsic tumor cells mechanisms and correlations with clinical parameters along with their utility for medical practice and detection techniques.

Size-based separation methods of circulating tumor cells

Circulating tumor cells (CTCs) originate from the primary tumor mass and enter into the peripheral bloodstream. Compared to other "liquid biopsy" portfolios such as exosome, circulating tumor DNA/RNA (ctDNA/RNA), CTCs have incomparable advantages in analyses of transcriptomics, proteomics, and signal colocalization. Hence, CTCs hold the key to understanding the biology of metastasis and play a vital role in cancer diagnosis, treatment monitoring, and prognosis. Size-based enrichment features are prominent in CTC isolation. It is a label-free, simple and fast method. Enriched CTCs remain unmodified and viable for a wide range of subsequent analyses. In this review, we comprehensively summarize the differences of size and deformability between CTCs and blood cells, which would facilitate the development of technologies of size-based CTC isolation. Then we review representative size-/deformability-based technologies available for CTC isolation and highlight the recent achievements in molecular analysis of isolated CTCs. To wrap up, we discuss the substantial challenges facing the field, and elaborate on prospects.

Circulating Tumor Cells and Circulating Tumor DNA: Challenges and Opportunities on the Path to Clinical Utility

Recent technological advances have enabled the detection and detailed characterization of circulating tumor cells (CTC) and circulating tumor DNA (ctDNA) in blood samples from patients with cancer. Often referred to as a "liquid biopsy," CTCs and ctDNA are expected to provide real-time monitoring of tumor evolution and therapeutic efficacy, with the potential for improved cancer diagnosis and treatment. In this review, we focus on these opportunities as well as the challenges that should be addressed so that these tools may eventually be implemented into routine clinical care.

Organ-Tumor-on-a-Chip for Chemosensitivity Assay: A Critical Review

With a mortality rate over 580,000 per year, cancer is still one of the leading causes of death worldwide. However, the emerging field of microfluidics can potentially shed light on this puzzling disease. Unique characteristics of microfluidic chips (also known as micro-total analysis system) make them excellent candidates for biological applications. The ex vivo approach of tumor-on-a-chip is becoming an indispensable part of personalized medicine and can replace in vivo animal testing as well as conventional in vitro methods. In tumor-on-a-chip, the complex three-dimensional (3D) nature of malignant tumor is co-cultured on a microfluidic chip and high throughput screening tools to evaluate the efficacy of anticancer drugs are integrated on the same chip. In this article, we critically review the cutting edge advances in this field and mainly categorize each tumor-on-a-chip work based on its primary organ. Specifically, design, fabrication and characterization of tumor microenvironment; cell culture technique; transferring mechanism of cultured cells into the microchip; concentration gradient generators for drug delivery; in vitro screening assays of drug efficacy; and pros and cons of each microfluidic platform used in the recent literature will be discussed separately for the tumor of following organs: (1) Lung; (2) Bone marrow; (3) Brain; (4) Breast; (5) Urinary system (kidney, bladder and prostate); (6) Intestine; and (7) Liver. By comparing these microchips, we intend to demonstrate the unique design considerations of each tumor-on-a-chip based on primary organ, e.g., how microfluidic platform of lung-tumor-on-a-chip may differ from liver-tumor-on-a-chip. In addition, the importance of heart–liver–intestine co-culture with microvasculature in tumor-on-a-chip devices for in vitro chemosensitivity assay will be discussed. Such system would be able to completely evaluate the absorption, distribution, metabolism, excretion and toxicity (ADMET) of anticancer drugs and more realistically recapitulate tumor in vivo-like microenvironment.

Circulating Tumor Cell Isolation and Analysis

Isolation and analysis of cancer cells from body fluids have significant implications in diagnosis and therapeutic treatment of cancers. Circulating tumor cells (CTCs) are cancer cells circulating in the peripheral blood or spreading iatrogenically into blood vessels, which is an early step in the cascade of events leading to cancer metastasis. Therefore, CTCs can be used for diagnosing for therapeutic treatment, prognosing a given anticancer intervention, and estimating the risk of metastatic relapse. However, isolation of CTCs is a significant technological challenge due to their rarity and low recovery rate using traditional purification techniques. Recently microfluidic devices represent a promising platform for isolating cancer cells with high efficiency in processing complex cellular fluids, with simplicity, sensitivity, and throughput. This review summarizes recent methods of CTC isolation and analysis, as well as their applications in clinical studies.

Alternating current electrohydrodynamics in microsystems: Pushing biomolecules and cells around on surfaces

Electrohydrodynamics (EHD) deals with the fluid motion induced by an electric field. This phenomenon originally developed in physical science, and engineering is currently experiencing a renaissance in microfluidics. Investigations by Taylor on Gilbert's theory proposed in 1600 have evolved to include multiple contributions including the promising effects arising from electric field interactions with cells and particles to influence their behaviour on electrode surfaces. Theoretical modelling of electric fields in microsystems and the ability to determine shear forces have certainly reached an advanced state. The ability to deftly manipulate microscopic fluid flow in bulk fluid and at solid/liquid interfaces has enabled the controlled assembly, coagulation, or removal of microstructures, nanostructures, cells, and molecules on surfaces. Furthermore, the ability of electrohydrodynamics to generate fluid flow using surface shear forces generated within nanometers from the surface and their application in bioassays has led to recent advancements in biomolecule, vesicle and cellular detection across different length scales. With the integration of Alternating Current Electrohydrodynamics (AC-EHD) in cellular and molecular assays proving to be highly fruitful, challenges still remain with respect to understanding the discrepancies between each of the associated ac-induced fluid flow phenomena, extending their utility towards clinical diagnostic development, and utilising them in tandem as a standard tool for disease monitoring. In this regard, this article will review the history of electrohydrodynamics, followed by some of the recent developments in the field including a new dimension of electrohydrodynamics that deals with the utilization of surface shear forces for the manipulation of biological cells or molecules on electrode surfaces. Recent advances and challenges in the use of electrohydrodynamic forces such as dielectrophoresis and ac electrosmosis for the detection of biological analytes are also reviewed. Additionally, the fundamental mechanisms of fluid flow using electrohydrodynamics forces, which are still evolving, are reviewed. Challenges and future directions are discussed from the perspective of both fundamental understanding and potential applications of these nanoscaled shear forces in diagnostics.

3D Silicon Microstructures: A New Tool for Evaluating Biological Aggressiveness of Tumor Cells

In this work, silicon micromachined structures (SMS), consisting of arrays of 3- μ m-thick silicon walls separated by 50- μm-deep, 5- μ m-wide gaps, were applied to investigate the behavior of eight tumor cell lines, with different origins and biological aggressiveness, in a three-dimensional (3D) microenvironment. Several cell culture experiments were performed on 3D-SMS and cells grown on silicon were stained for fluorescence microscopy analyses. Most of the tumor cell lines recognized in the literature as highly aggressive (OVCAR-5, A375, MDA-MB-231, and RPMI-7951) exhibited a great ability to enter and colonize the narrow deep gaps of the SMS, whereas less aggressive cell lines (OVCAR-3, Capan-1, MCF7, and NCI-H2126) demonstrated less penetration capability and tended to remain on top of the SMS. Quantitative image analyses of several fluorescence microscopy fields of silicon samples were performed for automatic cell recognition and count, in order to quantify the fraction of cells inside the gaps, with respect to the total number of cells in the examined field. Our results show that higher fractions of cells in the gaps are obtained with more aggressive cell lines, thus supporting in a quantitative way the observation that the behavior of tumor cells on the 3D-SMS depends on their aggressiveness level.

Sampling circulating tumor cells for clinical benefits: how frequent?

Circulating tumor cells (CTCs) are cells shed from tumors or metastatic sites and are a potential biomarker for cancer diagnosis, management, and prognostication. The majority of current studies use single or infrequent CTC sampling points. This strategy assumes that changes in CTC number, as well as phenotypic and molecular characteristics, are gradual with time. In reality, little is known today about the actual kinetics of CTC dissemination and phenotypic and molecular changes in the blood of cancer patients. Herein, we show, using clinical case studies and hypothetical simulation models, how sub-optimal CTC sampling may result in misleading observations with clinical consequences, by missing out on significant CTC spikes that occur in between sampling times. Initial studies using highly frequent CTC sampling are necessary to understand the dynamics of CTC dissemination and phenotypic and molecular changes in the blood of cancer patients. Such an improved understanding will enable an optimal, study-specific sampling frequency to be assigned to individual research studies and clinical trials and better inform practical clinical decisions on cancer management strategies for patient benefits.

Pharmacologic biomarkers in the development of stratified cancer medicine

Clinical pharmacologic research plays a vital role in cancer drug development. In recent years, biomarker studies have become integral to this process, specifically the use of pharmacologic biomarkers in the development of targeted therapies and their translation to clinical practice. In this overview, we discuss the validation of pharmacodynamics (PD) biomarkers and highlight the circulating tumor DNA as a promising cancer biomarker to illustrate how PD biomarkers can be powerful tools for guiding treatment strategies. We provide insights into PD biomarker approaches for future development of novel therapies and their role in cancer medicine. See all articles in this CCR focus section, "Progress in pharmacodynamic endpoints."

Emerging role of nanomaterials in circulating tumor cell isolation and analysis

Circulating tumor cells (CTCs) are low frequency cells found in the bloodstream after having been shed from a primary tumor. These cells are research targets because of the information they may potentially provide about both an individual cancer as well as the mechanisms through which cancer spreads in the process of metastasis. Established technologies exist for CTC isolation, but the recent progress and future of this field lie in nanomaterials. In this review, we provide perspective into historical CTC capture as well as current research being conducted, emphasizing the significance of the materials being used to fabricate these devices. The modern investigation into CTCs initially featured techniques that have since been commercialized. A major innovation in the field was the development of a microfluidic capture device, first fabricated in silicon and followed up with glass and thermopolymer devices. We then specifically highlight the technologies incorporating magnetic nanoparticles, carbon nanotubes, nanowires, nanopillars, nanofibers, and nanoroughened surfaces, graphene oxide and their fabrication methods. The nanoscale provides a new set of tools that has the potential to overcome current limitations associated with CTC capture and analysis. We believe the current trajectory of the field is in the direction of nanomaterials, allowing the improvements necessary to further CTC research.