EMT-independent detection of circulating tumor cells in human blood samples and pre-clinical mouse models of metastasis

Circulating tumor cells are a good predictor of tumor recurrence in clinical patients with gastric cancer

Circulating tumor cells (CTCs) as a liquid biopsy have great potential in clinical applications and basic cancer research, but their clinical use in gastric cancer remains unclear. This study investigated whether CTCs could be used as a potential prognosis predictor in patients with gastric cancer. A total of 120 patients with pathologically confirmed gastric cancer were enrolled from January 1, 2015, to December 1, 2019. All patients were initially diagnosed without previous treatment, and then the number of CTCs was detected using the NEimFISH method before radical surgical resection. Regular follow-up was performed in all patients, and the correlations between the number of CTCs and clinical endpoints, such as disease-free survival (DFS) and overall survival (OS), were evaluated. The univariate and multivariate hazard ratios were calculated using the Cox proportional hazard model. Based on the number of CTCs, we defined CTCs ≥ 2 per 7.5 mL of whole blood as the positive group and CTCs < 2 as the negative group. Among the 120 patients who underwent CTC detection before surgery, the rate of CTC-positive patients was 64.17% (77/120) of which stage I and II patients accounted for 22.50% and stage III patients accounted for 41.67% (P = 0.014). By detecting CTCs before surgery and at the time of recurrence, the number of CTCs tends to increase concomitantly with disease progression (median: 2 VS 5 per 7.5 mL). Multivariate analysis showed that age (HR, 0.259; 95% CI, 0.101-0.662; P = 0.005), D-dimer (HR, 3.146; 95% CI, 1.169-8.461; P = 0.023), and lymph node metastasis (HR, 0.207; 95% CI, 0.0071-0.603; P = 0.004) were factors correlated with CTCs. In addition, the median follow-up of all the patients was 38.0 months (range of 28-80 months); the DFS in CTC-positive patients was significantly shorter than that of the CTC-negative patients, and a significant difference was found based on the Cox proportional hazard regression model analysis (44.52 ± 2.83 m vs. 74.99 ± 2.78 m, HR = 4.550, P = 0.018). The OS was shorter in the CTC-positive group than in the CTC-negative group before the operation, but the result was not significant based on the Cox proportional hazard regression model analysis (47.58 ± 2.46 m vs. 70.68 ± 3.53 m, HR = 2.261, P = 0.083). The number of CTCs tends to increase concomitantly with disease progression. In addition, the detection of CTCs was an independent predictor of shorter DFS in gastric cancer. However, the relationship between CTCs and OS needs to be determined in future studies.

Poor patient outcome correlates with active engulfment of cytokeratin positive CTCs within cancer-associated monocyte population in lung cancer

High rates of mortality in non-small cell lung cancer lung cancer is due to inherent and acquired resistance to systemic therapies and subsequent metastatic burden. Metastasis is supported by suppression of the immune system at secondary organs and within the circulation. Modulation of the immune system is now being exploited as a therapeutic target with immune checkpoint inhibitors. The tracking of therapeutic efficacy in a real-time can be achieved with liquid biopsy, and evaluation of circulating tumour cells and the associated immune cells. A stable liquid biopsy biomarker for non-small cell lung cancer lung cancer has yet to be approved for clinical use. We performed a cross-sectional single-site study, and collected liquid biopsies from patients diagnosed with early, locally advanced, or metastatic lung cancer, undergoing surgery, or systemic therapy (chemotherapy/checkpoint inhibitors). Evaluation of overall circulating tumour cell counts, or cluster counts did not correlate with patient outcome. Interestingly, the numbers of Pan cytokeratin positive circulating tumour cells engulfed by tumour associated monocytes correlated strongly with patient outcome independent of circulating tumour cell counts and the use of checkpoint inhibitors. We suggest that Pan cytokeratin staining within monocytes is an important indicator of tumour-associated inflammation post-therapy and an effective biomarker with strong prognostic capability for patient outcome.

Analyzing circulating tumor cells and epithelial-mesenchymal transition status of papillary thyroid carcinoma patients following thyroidectomy: a prospective cohort study

BACKGROUND

This study investigated the prevalence and subtype distribution of circulating tumor cells (CTCs) in patients with papillary thyroid cancer (PTC) before and after thyroidectomy to determine the potential of CTC count as a noninvasive marker of the efficacy of surgical treatment in PTC.

MATERIALS AND METHODS

Between January 2021 and January 2022, 62 PTC patients who underwent thyroidectomy at Seoul National University Bundang Hospital were prospectively evaluated. Peripheral blood samples (7.5 ml) were collected from each patient for CTC analysis before surgery and at 2 weeks and 3 months after surgery. CTC count and the distribution of CTC subtypes, including epithelial, epithelial-mesenchymal, and mesenchymal phenotypes, were analyzed using the negative selection method and immunofluorescence staining. The relationship between CTC count and clinicopathological characteristics was analyzed before and after surgery.

RESULTS

Before surgery, CTCs were detected in 87% (54/62) of patients; the mean CTC count was 8.0 and the median was 5.0 in 7.5 ml of peripheral blood. The mesenchymal or epithelial-mesenchymal phenotypes were predominant. After thyroidectomy, the mean and median CTC count values decreased to 5.3 and 2.5, respectively, at 2 weeks and to 4.3 and 3.0, respectively, at 3 months. This postoperative reduction in CTCs was more pronounced in patients with lymphatic invasion, lymph node metastasis, or BRAF V600E mutation.

CONCLUSION

CTCs were detected in patients with PTC with a predominance of cells undergoing epithelial-mesenchymal transition. The CTC count decreased postoperatively, suggesting that liquid biopsy with CTC detection could be a valuable noninvasive tool for monitoring the efficacy of surgery in PTC.

Circulating tumor cells as liquid biopsy markers in cancer patients

Over the past decade, novel methods for enrichment and identification of cancer cells circulating in the blood have been established. Blood-based detection of cancer cells and other tumor-associated products can be summarized under the term of Liquid Biopsy. Circulating tumor cells (CTCs) have been used for diagnosis, risk stratification and treatment selection as well as treatment monitoring in several studies over the past years, thus representing a valuable biomarker for cancer patients. A plethora of methods to enrich, detect and analyze CTCs has been established. In contrast to other liquid biopsy analytes (e.g. ctDNA), CTCs represent a viable analyte that provides a unique opportunity to understand the underlaying biology of cancer and the metastatic cascade on the molecular level. In this review, we provide an overview on the current methods used for enrichment, detection, molecular and functional characterization of CTCs.

Microfluidics-Based Technologies for the Assessment of Castration-Resistant Prostate Cancer

Castration-resistant prostate cancer remains a significant clinical challenge, wherein patients display no response to existing hormone therapies. The standard of care often includes aggressive treatment options using chemotherapy, radiation therapy and various drugs to curb the growth of additional metastases. As such, there is a dire need for the development of innovative technologies for both its diagnosis and its management. Traditionally, scientific exploration of prostate cancer and its treatment options has been heavily reliant on animal models and two-dimensional (2D) in vitro technologies. However, both laboratory tools often fail to recapitulate the dynamic tumor microenvironment, which can lead to discrepancies in drug efficacy and side effects in a clinical setting. In light of the limitations of traditional animal models and 2D in vitro technologies, the emergence of microfluidics as a tool for prostate cancer research shows tremendous promise. Namely, microfluidics-based technologies have emerged as powerful tools for assessing prostate cancer cells, isolating circulating tumor cells, and examining their behaviour using tumor-on-a-chip models. As such, this review aims to highlight recent advancements in microfluidics-based technologies for the assessment of castration-resistant prostate cancer and its potential to advance current understanding and to improve therapeutic outcomes.

Microfluidic Isolation of Disseminated Tumor Cells from the Bone Marrow of Breast Cancer Patients

Disseminated tumor cells (DTCs) in the bone marrow (BM) of breast cancer (BC) patients are putative precursors of metastatic disease, and their presence is associated with an adverse clinical outcome. To achieve the personalization of therapy on a clinical routine level, the characterization of DTCs and in vitro drug testing on DTCs are of great interest. Therefore, biobanking methods, as well as novel approaches to DTC isolation, need to be developed. In this study, we established a protocol for the biobanking of BM samples and evaluated a microfluidic-based separation system (Parsortix®) for the enrichment of cryopreserved DTCs. We were able to successfully isolate viable DTCs after the prior cryopreservation of BM samples. We calculated a significant increase of up to 90-fold in harvested DTCs with the proposed method compared to the current standard techniques, opening up new analysis possibilities for DTCs. Our advanced method further presents options for 3D DTC cultures, enabling the individualized testing of targeted therapies for BC patients. In conclusion, we present a novel approach for DTC enrichment, with possibilities for future clinical implications.

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.

High-performance glass filters for capturing and culturing circulating tumor cells and cancer-associated fibroblasts

Various liquid biopsy methods have been developed for the non-invasive and early detection of diseases. In particular, the detection of circulating tumor cells (CTCs) and cancer-associated fibroblasts (CAFs) in blood has been receiving a great deal of attention. We have been developing systems and materials to facilitate such liquid biopsies. In this study, we further developed glass filters (with various patterns of holes, pitches, and non-adhesive coating) that can capture CTCs, but not white blood cells. We optimized the glass filters to capture CTCs, and demonstrated that they could be used to detect CTCs from lung cancer patients. We also used the optimized glass filters for detecting CAFs. Additionally, we further developed a system for visualizing the captured cells on the glass filters. Finally, we demonstrated that we could directly culture the captured cells on the glass filters. Based on these results, our high-performance glass filters appear to be useful for capturing and culturing CTCs and CAFs for further examinations.

Recent Advances in Methods for Circulating Tumor Cell Detection

Circulating tumor cells (CTCs) are released from primary tumors and transported through the body via blood or lymphatic vessels before settling to form micrometastases under suitable conditions. Accordingly, several studies have identified CTCs as a negative prognostic factor for survival in many types of cancer. CTCs also reflect the current heterogeneity and genetic and biological state of tumors; so, their study can provide valuable insights into tumor progression, cell senescence, and cancer dormancy. Diverse methods with differing specificity, utility, costs, and sensitivity have been developed for isolating and characterizing CTCs. Additionally, novel techniques with the potential to overcome the limitations of existing ones are being developed. This primary literature review describes the current and emerging methods for enriching, detecting, isolating, and characterizing CTCs.

Microfluidic techniques for isolation, formation, and characterization of circulating tumor cells and clusters

Circulating tumor cell (CTC) clusters that are shed from the primary tumor into the bloodstream are associated with a poor prognosis, elevated metastatic potential, higher proliferation rate, and distinct molecular features compared to single CTCs. Studying CTC clusters may give us information on the differences in the genetic profiles, somatic mutations, and epigenetic changes in circulating cells compared to the primary tumor and metastatic sites. Microfluidic systems offer the means of studying CTC clusters through the ability to efficiently isolate these rare cells from the whole blood of patients in a liquid biopsy. Microfluidics can also be used to develop in vitro models of CTC clusters and make possible their characterization and analysis. Ultimately, microfluidic systems can offer the means to gather insight on the complexities of the metastatic process, the biology of cancer, and the potential for developing novel or personalized therapies. In this review, we aim to discuss the advantages and challenges of the existing microfluidic systems for working with CTC clusters. We hope that an improved understanding of the role microfluidics can play in isolation, formation, and characterization of CTC clusters, which can lead to increased sophistication of microfluidic platforms in cancer research.

Clinical Utility of Circulating Tumor Cells in Patients With Esophageal Cancer

Background

As one of the most aggressive gastrointestinal tract cancers, esophageal carcinoma (EC) had the tenth morbidity and sixth mortality rate globally in 2020. This study was conducted to investigate whether circulating tumor cells (CTCs) could be used as diagnostic and prognostic tools for patients with EC.

Methods

Peripheral blood samples were collected from 129 patients newly diagnosed with EC, 17 individuals with benign diseases, and 75 healthy donors for CTC analysis using the negative enrichment-fluorescence in situ hybridization (NE-FISH) approach. The relationship between CTCs (counts and karyotypes) and clinicopathological features was then investigated. Moreover, overall survival (OS) and progression-free survival (PFS) were analyzed to evaluate the predictive value of CTCs.

Results

The detection of CTCs using the NE-FISH approach helped in differentiating patients with EC from benign or healthy controls at a threshold of 2 per 3.2 ml peripheral blood with a sensitivity and specificity of 70.54% and 96.74%, respectively (area under the curve = 0.826, 95% CI 0.770–0.874, p < 0.001). The CTC count was associated with tumor depth (p = 0.012), but there was no correlation with other clinicopathological characteristics. Furthermore, the proportion of CTCs with chromosome 7 triploidy was linked to distant metastasis (p = 0.033) and TNM stage (p = 0.002). The OS was significantly shorter for patients with CTCs ≥ 3 than for those with CTCs < 3. Univariate analysis revealed that sex, vascular invasion, distant metastasis, tumor depth, lymph node metastasis, and TNM stage were the significant prognostic factors for patients with EC. Multivariate analysis demonstrated that distant metastasis (hazard ratio (HR) 3.262, 95% CI 1.671–6.369, p = 0.001 for PFS; HR 3.759, 95% CI 1.867–7.571, p < 0.001 for OS) was a significant prognostic factor for patients with EC.

Conclusions

Detection of CTCs using NE-FISH could be helpful in the diagnosis of EC. The proportion of CTCs with chromosome 7 triploidy was related to distant metastasis and TNM stage. Patients with CTCs ≥ 3 had short OS, while distant metastasis was an independent factor indicating a poor prognosis for patients with EC.

MicroRNA-148a Inhibits Hepatocellular Carcinoma Cell Growth via Epithelial-to-Mesenchymal Transition and PI3K/AKT Signaling Pathways by Targeting Death Receptor-5

The purpose of this study was to investigate the role of microRNA-148a (miR-148a) in hepatocellular carcinoma (HCC) metastasis and explore its potential mechanism in HCC cells. Expression levels of miR-148a were measured using qRT-PCR in 120 HCC tissue samples and two HCC cell lines. Migration and invasion assays were used to determine the role of miR-148a in HCC cells. Flow cytometry was used to access the effect of miR-148a on cell cycle of HCC cells. Western blot was performed to analyze the effect of miR-148a on epithelial-to-mesenchymal transition (EMT) and PI3K/AKT signaling pathways in HCC cells. Luciferase reporter assay was conducted to explore the downstream targets and biological function of miR-148a in HCC cells. The results showed that level of miR-148a was significantly downregulated in both HCC tissue and plasma samples in HCC patients. A higher level of miR-148a was positively correlated with better survival time and prognosis of HCC patients. Transfection of miR-148a inhibited the proliferation, migration and invasion of HCC cell lines. Transfection of miR-148a arrested HCC cells at S phase and promoted apoptosis of HCC cells. Death receptor-5 (DR-5) was identified as a direct target of miR-148a in HCC cell lines. Western blot and qRT-PCR analyses showed that miR-148a upregulated EMT and downregulated PI3K/AKT signaling pathways in HCC cell lines. In conclusion, data in the current study indicate that miR-148a inhibits HCC cells growth via downregulation of EMT and PI3K/AKT signaling pathways by targeting death receptor. These data suggest that miR-148a may serve as a therapeutic target for HCC cancer therapy in the future.

Breast cancer circulating tumor cells with mesenchymal features-an unreachable target?

Circulating tumor cells (CTCs) mediate dissemination of solid tumors and can be an early sign of disease progression. Moreover, they show a great potential in terms of non-invasive, longitudinal monitoring of cancer patients. CTCs have been extensively studied in breast cancer (BC) and were shown to present a significant phenotypic plasticity connected with initiation of epithelial-mesenchymal transition (EMT). Apart from conferring malignant properties, EMT affects CTCs recovery rate, making a significant portion of CTCs from patients’ samples undetected. Wider application of methods and markers designed to isolate and identify mesenchymal CTCs is required to expand our knowledge about the clinical impact of mesenchymal CTCs. Therefore, here we provide a comprehensive review of clinical significance of mesenchymal CTCs in BC together with statistical analysis of previously published data, in which we assessed the suitability of a number of methods/markers used for isolation of CTCs with different EMT phenotypes, both in in vitro spike-in tests with BC cell lines, as well as clinical samples. Results of spiked-in cell lines indicate that, in general, methods not based on epithelial enrichment only, capture mesenchymal CTCs much more efficiently that CellSearch^® (golden standard in CTCs detection), but at the same time are not much inferior to Cell Search^®, though large variation in recovery rates of added cells among the methods is observed. In clinical samples, where additional CTCs detection markers are needed, positive epithelial-based CTCs enrichment was the most efficient in isolating CTCs with mesenchymal features from non-metastatic BC patients. From the marker side, PI3K and VIM were contributing the most to detection of CTCs with mesenchymal features (in comparison to SNAIL) in non-metastatic and metastatic BC patients, respectively. However, additional data are needed for more robust identification of markers for efficient detection of CTCs with mesenchymal features.

Cancer nanotechnology: current status and perspectives

Modern medicine has been waging a war on cancer for nearly a century with no tangible end in sight. Cancer treatments have significantly progressed, but the need to increase specificity and decrease systemic toxicities remains. Early diagnosis holds a key to improving prognostic outlook and patient quality of life, and diagnostic tools are on the cusp of a technological revolution. Nanotechnology has steadily expanded into the reaches of cancer chemotherapy, radiotherapy, diagnostics, and imaging, demonstrating the capacity to augment each and advance patient care. Nanomaterials provide an abundance of versatility, functionality, and applications to engineer specifically targeted cancer medicine, accurate early-detection devices, robust imaging modalities, and enhanced radiotherapy adjuvants. This review provides insights into the current clinical and pre-clinical nanotechnological applications for cancer drug therapy, diagnostics, imaging, and radiation therapy.

Morphological features of breast cancer circulating tumor cells in blood after physical and biological type of isolation

BACKGROUND

Circulating tumor cells (CTCs) have become an important biomarker in breast cancer. Different isolation tech-niques based on their biological or physical features were established. Currently, the most widely used methods for visualization after their separation are based on immunofluorescent staining, which does not provide the information on the morphology.

MATERIALS AND METHODS

The aim of this study was to evaluate how two different separation techniques affect cell morphology and to analyse cell morphology with techniques used in routine cytopathological laboratory. A direct side-by-side comparison of physical (Parsortix®) and biological (MACS®) separation technique was performed.

RESULTS

In the preclinical setting, both isolation techniques retained the viability and antigenic characteristics of MCF7 breast cancer cells. Some signs of degeneration such as cell swelling, cytoplasmic blebs, villous projections and vacuolization were observed. In metastatic breast cancer patient cohort, morphological features of isolated CTCs were dependent on the separation technique. After physical separation, CTCs with preserved cell morphology were detected. After biological separation the majority of the isolated CTCs were so degenerated that their identity was difficult to confirm.

CONCLUSIONS

Taken together, physical separation is a suitable technique for detection of CTCs with preserved cell morphology for the use in a routine cytopathological laboratory.