Ex vivo culture of circulating tumour cells derived from non-small cell lung cancer

Circulating tumour cells predict recurrences and survival in head and neck squamous cell carcinoma patients

Patients with head and neck squamous cell carcinoma (HNSCC) are at a high risk of developing recurrence and secondary cancers. This study evaluates the prognostic and surveillance utilities of circulating tumour cells (CTCs) in HNSCC. A total of 154 HNSCC patients were recruited and followed up for 4.5 years. Blood samples were collected at baseline and follow-up. CTCs were isolated using a spiral microfluid device. Recurrence and death due to cancer were assessed during the follow-up period. In patients with HNSCC, the presence of CTCs at baseline was a predictor of recurrence (OR = 8.40, p < 0.0001) and death (OR= ∞, p < 0.0001). Patients with CTCs at baseline had poor survival outcomes (p < 0.0001). Additionally, our study found that patients with CTCs in a follow-up appointment were 2.5 times more likely to experience recurrence or death from HNSCC (p < 0.05) prior to their next clinical visit. Our study highlights the prognostic and monitoring utilities of CTCs' in HNSCC patients. Early identification of CTCs facilitates precise risk assessment, guiding treatment choices and ultimately enhancing patient outcomes.

Phenotyping neuroblastoma cells through intelligent scrutiny of stain-free biomarkers in holographic flow cytometry

To efficiently tackle certain tumor types, finding new biomarkers for rapid and complete phenotyping of cancer cells is highly demanded. This is especially the case for the most common pediatric solid tumor of the sympathetic nervous system, namely, neuroblastoma (NB). Liquid biopsy is in principle a very promising tool for this purpose, but usually enrichment and isolation of circulating tumor cells in such patients remain difficult due to the unavailability of universal NB cell-specific surface markers. Here, we show that rapid screening and phenotyping of NB cells through stain-free biomarkers supported by artificial intelligence is a viable route for liquid biopsy. We demonstrate the concept through a flow cytometry based on label-free holographic quantitative phase-contrast microscopy empowered by machine learning. In detail, we exploit a hierarchical decision scheme where at first level NB cells are classified from monocytes with 97.9% accuracy. Then we demonstrate that different phenotypes are discriminated within NB class. Indeed, for each cell classified as NB its belonging to one of four NB sub-populations (i.e., CHP212, SKNBE2, SHSY5Y, and SKNSH) is evaluated thus achieving accuracy in the range 73.6%-89.1%. The achieved results solve the realistic problem related to the identification circulating tumor cell, i.e., the possibility to recognize and detect tumor cells morphologically similar to blood cells, which is the core issue in liquid biopsy based on stain-free microscopy. The presented approach operates at lab-on-chip scale and emulates real-world scenarios, thus representing a future route for liquid biopsy by exploiting intelligent biomedical imaging.

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.

The application, safety, and future of ex vivo immune cell therapies and prognosis in different malignancies

Introduction

Immunotherapy has revolutionized how cancer is treated. Many of these immunotherapies rely on ex vivo expansion of immune cells, classically T cells. Still, several immunological obstacles remain, including tumor impermeability by immune cells and the immunosuppressive nature of the tumor microenvironment (TME). Logistically, high costs of treatment and variable clinical responses have also plagued traditional T cell-based immunotherapies.

Methods

To review the existing literature on cellular immunotherapy, the PubMed database was searched for publications using variations of the phrases "cancer immunotherapy", "ex vivo expansion", and "adoptive cell therapy". The Clinicaltrials.gov database was searched for clinical trials related to ex vivo cellular therapies using the same phrases. The National Comprehensive Cancer Network guidelines for cancer treatment were also referenced.

Results

To circumvent the challenges of traditional T cell-based immunotherapies, researchers have developed newer therapies including tumor infiltrating lymphocyte (TIL), chimeric antigen receptor (CAR), T cell receptor (TCR) modified T cell, and antibody-armed T cell therapies. Additionally, newer immunotherapeutic strategies have used other immune cells, including natural killer (NK) and dendritic cells (DC), to modulate the T cell immune response to cancers. From a prognostic perspective, circulating tumor cells (CTC) have been used to predict cancer morbidity and mortality.

Conclusion

This review highlights the mechanism and clinical utility of various types of ex vivo cellular therapies in the treatment of cancer. Comparing these therapies or using them in combination may lead to more individualized and less toxic chemotherapeutics.

Preclinical models to study patient-derived circulating tumor cells and metastasis

Circulating tumor cells (CTCs) that are detached from the tumor can be precursors of metastasis. The majority of studies focus on enumeration of CTCs from patient blood to predict recurrence and therapy outcomes. Very few studies have managed to expand CTCs to investigate their functional dynamics with respect to genetic changes, tumorigenic potential, and response to drug treatment. A growing amount of evidence based on successful CTC expansion has revealed novel therapeutic targets that are associated with the process of metastasis. In this review, we summarize the successes, challenges, and limitations that collectively contribute to the better understanding of metastasis using patient-derived CTCs as blood-borne seeds of metastasis. The roadblocks and future avenues to move CTC-based scientific discoveries forward are also discussed.

Ex vivo expansion of circulating tumour cells (CTCs)

Circulating tumour cells (CTCs) are a critical intermediate step in the process of cancer metastasis. The reliability of CTC isolation/purification has limited both the potential to report on metastatic progression and the development of CTCs as targets for therapeutic intervention. Here we report a new methodology, which optimises the culture conditions for CTCs using primary cancer cells as a model system. We exploited the known biology that CTCs thrive in hypoxic conditions, with their survival and proliferation being reliant on the activation of hypoxia-inducible factor 1 alpha (HIF-1α). We isolated epithelial-like and quasi-mesenchymal CTC phenotypes from the blood of a cancer patient and successfully cultured these cells for more than 8 weeks. The presence of CTC clusters was required to establish and maintain long-term cultures. This novel methodology for the long-term culture of CTCs will aid in the development of downstream applications, including CTC theranostics.

Deep learning assisted holography microscopy for in-flow enumeration of tumor cells in blood

Currently, detection of circulating tumor cells (CTCs) in cancer patient blood samples relies on immunostaining, which does not provide access to live CTCs, limiting the breadth of CTC-based applications. Here, we take the first steps to address this limitation, by demonstrating staining-free enumeration of tumor cells spiked into lysed blood samples using digital holographic microscopy (DHM), microfluidics and machine learning (ML). A 3D-printed module for laser assembly was developed to simplify the optical set up for holographic imaging of cells flowing through a sheath-based microfluidic device. Computational reconstruction of the holograms was performed to localize the cells in 3D and obtain the plane of best focus images to train deep learning models. We developed a custom-designed light-weight shallow Network dubbed s-Net and compared its performance against off-the-shelf CNN models including ResNet-50. The accuracy, sensitivity and specificity of the s-Net model was found to be higher than the off-the-shelf ML models. By applying an optimized decision threshold to mixed samples prepared in silico, the false positive rate was reduced from 1 × 10^-2 to 2.77 × 10^-4. Finally, the developed DHM-ML framework was successfully applied to enumerate spiked MCF-7 breast cancer cells and SkOV3 ovarian cancer cells from lysed blood samples containing white blood cells (WBCs) at concentrations typical of label-free enrichment techniques. We conclude by discussing the advances that need to be made to translate the DHM-ML approach to staining-free enumeration of actual CTCs in cancer patient blood samples.

Prognostic value of integrating circulating tumour cells and cell-free DNA in non-small cell lung cancer

Background

Non-small cell lung cancer (NSCLC) often presents at an incurable stage, and majority of patients will be considered for palliative treatment at some point in their disease. Despite recent advances, the prognosis remains poor, with a median overall survival of 12–18 months. Liquid biopsy-based biomarkers have emerged as potential candidates for predicting prognosis and response to therapy in NSCLC patients. This pilot study evaluated whether combining circulating tumour cells and clusters (CTCs) and cell-free DNA (cfDNA) can predict progression-free survival (PFS) in NSCLC patients.

Methods

CTC and cfDNA/ctDNA from advanced stage NSCLC patients were measured at study entry (T⁰) and 3-months post-treatment (T¹). CTCs were enriched using a spiral microfluidic chip and characterised by immunofluorescence. ctDNA was assessed using an UltraSEEK® Lung Panel. Kaplan-Meier plots were generated to investigate the contribution of the presence of CTC/CTC clusters and cfDNA for PFS. Cox proportional hazards analysis compared time to progression versus CTC/CTC cluster counts and cfDNA levels.

Results

Single CTCs were found in 14 out of 25 patients, while CTC clusters were found in 8 out of the 25 patients at T⁰. At T¹, CTCs were found in 7 out of 18 patients, and CTC clusters in 1 out of the 18 patients. At T⁰, CTC presence and the combination of CTC cluster counts with cfDNA levels were associated with shorter PFS, p = 0.0261, p = 0.0022, respectively.

Conclusions

Combining CTC cluster counts and cfDNA levels could improve PFS assessment in NSCLC patients. Our results encourage further investigation on the combined effect of CTC/cfDNA as a prognostic biomarker in a large cohort of advanced stage NSCLC patients.

Application of circulating tumour cells to predict response to treatment in head and neck cancer

Background

Local recurrence and metastasis remain the major causes of death in head and neck cancer (HNC) patients. Circulating tumour cells (CTCs) are shed from primary and metastatic sites into the circulation system and have been reported to play critical roles in the metastasis and recurrence of HNC. Here, we explored the use of CTCs to predict the response to treatment and disease progression in HNC patients.

Methods

Blood samples were collected at diagnosis from HNC patients (n = 119). CTCs were isolated using a spiral microfluidic device and were identified using immunofluorescence staining. Correlation of baseline CTC numbers to 13-week PET-CT data and multidisciplinary team consensus data were conducted.

Results

CTCs were detected in 60/119 (50.4%) of treatment naïve HNC patients at diagnosis. Baseline CTC numbers were higher in stage III vs. stage I-II p16-positive oropharyngeal cancers (OPCs) and other HNCs (p = 0.0143 and 0.032, respectively). In addition, we found that baseline CTC numbers may serve as independent predictors of treatment response, even after adjusting for other conventional prognostic factors. CTCs were detected in 10 out of 11 patients exhibiting incomplete treatment responses.

Conclusions

We found that baseline CTC numbers are correlated with treatment response in patients with HNC. The expression level of cell-surface vimentin (CSV) on CTCs was significantly higher in patients with persistent or progressive disease, thus providing additional prognostic information for stratifying the risk at diagnosis in HNC patients. The ability to detect CTCs at diagnosis allows more accurate risk stratification, which in the future may be translated into better patient selection for treatment intensification and/or de-intensification strategies.

Supplementary information

The online version contains supplementary material available at 10.1007/s13402-022-00681-w.

In vitro cultures of circulating tumor cells: a potential tool to unravel drug sensitivity

Since taking part as leading actors in driving the metastatic process, circulating tumor cells (CTCs) have displayed a wide range of potential applications in the cancer-related research field. Besides their well-proved prognostic value, the role of CTCs in both predictive and diagnostics terms might be extremely informative about cancer properties and therefore highly helpful in the clinical decision-making process. Unfortunately, CTCs are scarcely released in the blood circulation and their counts vary a lot among different types of cancer, therefore CTC detection and consequent characterization are still highly challenging. In this context, in vitro CTC cultures could potentially offer a great opportunity to expand the number of tumor cells isolated at different stages of the disease and thus simplify the analysis of their biological and molecular features, allowing a deeper comprehension of the nature of neoplastic diseases. The aim of this review is to highlight the main attempts to establish in vitro CTC cultures from patients harboring different tumor types in order to highlight how powerful this practice could be, especially in optimizing the therapeutic strategies available in clinical practice and potentially preventing or contrasting the development of treatment resistance.

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.

Clinical Applications of Circulating Tumour Cells and Circulating Tumour DNA in Non-Small Cell Lung Cancer-An Update

Despite efforts to improve earlier diagnosis of non-small cell lung cancer (NSCLC), most patients present with advanced stage disease, which is often associated with poor survival outcomes with only 15% surviving for 5 years from their diagnosis. Tumour tissue biopsy is the current mainstream for cancer diagnosis and prognosis in many parts of the world. However, due to tumour heterogeneity and accessibility issues, liquid biopsy is emerging as a game changer for both cancer diagnosis and prognosis. Liquid biopsy is the analysis of tumour-derived biomarkers in body fluids, which has remarkable advantages over the use of traditional tumour biopsy. Circulating tumour cells (CTCs) and circulating tumour DNA (ctDNA) are two main derivatives of liquid biopsy. CTC enumeration and molecular analysis enable monitoring of cancer progression, recurrence, and treatment response earlier than traditional biopsy through a minimally invasive liquid biopsy approach. CTC-derived ex-vivo cultures are essential to understanding CTC biology and their role in metastasis, provide a means for personalized drug testing, and guide treatment selection. Just like CTCs, ctDNA provides opportunity for screening, monitoring, treatment evaluation, and disease surveillance. We present an updated review highlighting the prognostic and therapeutic significance of CTCs and ctDNA in NSCLC.

Modulation of Biological Responses of Tumor Cells Adhered to Poly(2-methoxyethyl acrylate) with Increasing Cell Viability under Serum-Free Conditions

Circulating tumor cells in body fluids are important biomarkers in cancer diagnosis. The culture of tumor cells isolated from body fluids can provide intrinsic information about tumors and can be used to screen for the best anticancer drugs. However, the culture of primary tumor cells has been hindered by their low viability and difficulties in recapitulating the phenotype of primary tumors in in vitro culture. The culture of tumor cells under serum-free conditions is one of the methodologies to maintain the phenotype and genotype of primary tumors. Poly(2-methoxyethyl acrylate) (PMEA)-coated substrates have been investigated to prolong the proliferation of tumor cells under serum-free conditions. In this study, we investigated the detailed behavior and the mechanism of the increase in tumor cell viability after adherence to PMEA substrates. The blebbing formation of tumor cells on PMEA was attributed not to apoptosis but to the low adhesion strength of cells on PMEA. Moreover, blebbing tumor cells showed amoeboid movement and formed clusters with other cells via N-cadherin, leading to an increase in tumor cell viability. Furthermore, the behaviors of tumor cells adhered to PMEA under serum-free conditions were involved in the activation of the PI3K and Rho-associated protein kinase pathways. Thus, we propose that PMEA would be suitable for the development of devices to cultivate primary tumor cells under serum-free conditions for the label-free diagnosis of cancer.

Generation and Culture of Organotypic Breast Carcinoma Spheroids for the Study of Drug Response in a 3D Microfluidic Device

Breast cancer (BC) is a leading cause of cancer death among women worldwide. To better understand and predict therapeutic response in BC patient developing a fast, low-cost, and reliable preclinical tumor from patient's tumor specimen is needed. Here, we describe the development of a preclinical model of BC through the generation and ex vivo culture of patient-derived organotypic tumor spheroids (PDOTS) in a 3D microfluidic device. Moreover, the real-time screening of conventional chemotherapy agents on cultured PDOTS is also described.

Lensless imaging-based discrimination between tumour cells and blood cells towards circulating tumour cell cultivation

Circulating tumour cells (CTCs) are recognized as important markers for cancer research. Nonetheless, the extreme rarity of CTCs in blood samples limits their availability for multiple characterization. The cultivation of CTCs is still technically challenging due to the lack of information of CTC proliferation, and it is difficult for conventional microscopy to monitor CTC cultivation owing to low throughput. In addition, for precise monitoring, CTCs need to be distinguished from the blood cells which co-exist with CTCs. Lensless imaging is an emerging technique to visualize micro-objects over a wide field of view, and has been applied for various cytometry analyses including blood tests. However, discrimination between tumour cells and blood cells was not well studied. In this study, we evaluated the potential of the lensless imaging system as a tool for monitoring CTC cultivation. Cell division of model tumour cells was examined using the lensless imaging system composed of a simple setup. Subsequently, we confirmed that tumour cells, JM cells (model lymphocytes), and erythrocytes exhibited cell line-specific patterns on the lensless images. After several discriminative parameters were extracted, discrimination between the tumour cells and other blood cells was demonstrated based on linear discriminant analysis. We also combined the highly efficient CTC recovery device, termed microcavity array, with the lensless-imaging to demonstrate recovery, monitoring and discrimination of the tumour cells spiked into whole blood samples. This study indicates that lensless imaging can be a powerful tool to investigate CTC proliferation and cultivation.

Clinical Utility of Circulating Tumor Cells in the Early Detection of Lung Cancer in Patients with a Solitary Pulmonary Nodule

Objective: Lung cancer is the most common cancer and can appear as a solitary pulmonary nodule. Early detection of lung cancer in this patient population would be beneficial for the disease management. In this study, the potential application of circulating tumor cells (CTCs) on early detection of lung cancer in this population was investigated. Methods: The number of CTCs in bronchoalveolar lavage fluid and serum levels of tumor-related markers, cancer antigen 125 (CA125), carcinoembryonic antigen (CEA) and neuron-specific enolase (NSE) were measured in patients with a solitary pulmonary nodule. The association between CTCs and lung cancer was examined. The diagnosis performances of CTCs and selected tumor-related markers were compared. Results: The CTC positivity was significantly associated with lung cancer (P = .009). The sensitivity of CTCs and CA125, CEA, NSE, and CA125/CEA/NSE was 75%, 5.6%, 0%, 25%, and 33%, respectively. The sensitivity of CTCs was improved from 75% to 83% by the combination with CA125 or NSE. Conclusion: CTCs may be helpful for the early detection of lung cancer in patients with a solitary pulmonary nodule.

Bridging the Gaps between Circulating Tumor Cells and DNA Methylation in Prostate Cancer

Prostate cancer is the second most common male malignancy, with a highly variable clinical presentation and outcome. Therefore, diagnosis, prognostication, and management remain a challenge, as available clinical, imaging, and pathological parameters provide limited risk assessment. Thus, many biomarkers are under study to fill this critical gap, some of them based on epigenetic aberrations that might be detected in liquid biopsies. Herein, we provide a critical review of published data on the usefulness of DNA methylation and circulating tumor cells in diagnosis and treatment decisions in cases of prostate cancer, underlining key aspects and discussing the importance of these advances to the improvement of the management of prostate cancer patients. Using minimally invasive blood tests, the detection of highly specific biomarkers might be crucial for making therapeutic decisions, determining response to specific treatments, and allowing early diagnosis.

Detection of EGFR Mutations in Plasma cfDNA and Paired CTCs of NSCLC Patients before and after Osimertinib Therapy Using Crystal Digital PCR

Circulating tumor DNA (ctDNA) analysis has clinical utility in EGFR mutant NSCLC. Circulating tumor cells (CTCs) consist a unique source of information at the cellular level. Digital PCR (dPCR) is a valuable tool for accurate and valid analysis of gene mutations in liquid biopsy analysis. In the present study we detected EGFR mutations in ctDNA and paired CTCs under osimertinib therapy at two time points using crystal dPCR and the naica® system (Stilla Technologies). We quantified mutation allele frequencies (MAF) of EGFR mutations in 91 plasma cfDNA samples of 48 EGFR mutant NSCLC patients and in 64 matched CTC-derived genomic DNA samples, and the FDA-cleared cobas® EGFR mutation test in 80 identical plasma samples. Direct comparison between crystal dPCR and the cobas EGFR assay revealed a high concordance for all EGFR mutations. Our comparison of crystal dPCR results in ctDNA with the corresponding primary tissue has shown a strong correlation. EGFR mutations analysis in paired CTC-derived gDNA revealed a high heterogeneity. Crystal dPCR offers the unique advantages of high analytical sensitivity, precision, and accuracy for detecting and quantifying multiple EGFR mutations in plasma cfDNA and CTCs of NSCLC patients.

Short-Term Ex Vivo Culture of CTCs from Advance Breast Cancer Patients: Clinical Implications

Simple Summary

Circulating tumor cells (CTCs) are responsible for metastasis, they represent tumor biology and have also predictive value for therapy monitoring and prognosis of metastatic breast cancer patients. In the blood, CTCs are found in low frequency and a small percentage of them survive. Therefore, achieving their expansion in vitro will allow performing characterization and functional analysis. In this work, we used growth factors and Nanoemulsions to support CTCs culture. We have seen that the CTCs subpopulation capable of ex vivo expanding presented mesenchymal and stem characteristics and loss of epithelial markers. Besides, CTC culture predicted progression-free survival.

Abstract

Background: Circulating tumor cells (CTC) have relevance as prognostic markers in breast cancer. However, the functional properties of CTCs or their molecular characterization have not been well-studied. Experimental models indicate that only a few cells can survive in the circulation and eventually metastasize. Thus, it is essential to identify these surviving cells capable of forming such metastases. Methods: We isolated viable CTCs from 50 peripheral blood samples obtained from 35 patients with advanced metastatic breast cancer using RosetteSep^TM for ex vivo culture. The CTCs were seeded and monitored on plates under low adherence conditions and with media supplemented with growth factors and Nanoemulsions. Phenotypic analysis was performed by immunofluorescence and gene expression analysis using RT-PCR and CTCs counting by the Cellsearch^® system. Results: We found that in 75% of samples the CTC cultures lasted more than 23 days, predicting a shorter Progression-Free Survival in these patients, independently of having ≥5 CTC by Cellsearch^®. We also observed that CTCs before and after culture showed a different gene expression profile. Conclusions: the cultivability of CTCs is a predictive factor. Furthermore, the subset of cells capable of growing ex vivo show stem or mesenchymal features and may represent the CTC population with metastatic potential in vivo.

Circulating tumor cells as a promising target for individualized drug susceptibility tests in cancer therapy

Circulating tumor cells (CTCs) play a crucial role in metastasis and became an emerging topic in today's cancer research. In addition, the analysis of CTCs in liquid biopsies will be a valuable tool for prognosis prediction and real time therapy monitoring. The characterization of CTCs may open up a new field of treatment strategy to prevent metastasis or maintain a stable disease. In 2013, the first cell cultures of CTCs have been established in vitro. Additionally, functional studies have been successfully performed over the last years. Meanwhile, more than 300 short-term CTC cultures and 42 long-term CTC cultures from a variety of tumor entities have been described. More than 45 inhibitors have already been tested for their efficacy to target CTCs in several studies in vitro as well as in xenograft mouse models in vivo. Here, we summarize the currently available data of these inhibition experiments and their effects in targeting CTCs. The results suggest that CTCs may be useful for individualized drug susceptibility testing.