Ultra-sensitive CTC-based liquid biopsy for pancreatic cancer enabled by large blood volume analysis.

The limited sensitivity of circulating tumor cell (CTC) detection in pancreatic adenocarcinoma (PDAC) stems from their extremely low concentration in the whole circulating blood, necessitating enhanced detection methodologies. This study sought to amplify assay-sensitivity by employing diagnostic leukapheresis (DLA) to screen large blood volumes. Sixty patients were subjected to DLA, with a median processed blood volume of ~ 2.8 L and approximately 5% of the resulting DLA-product analyzed using CellSearch (CS). Notably, DLA significantly increased CS-CTC detection to 44% in M0-patients and 74% in M1-patients, yielding a 60-fold increase in CS-CTC enumeration. DLA also provided sufficient CS-CTCs for genomic profiling, thereby delivering additional genomic information compared to tissue biopsy samples. DLA CS-CTCs exhibited a pronounced negative prognostic impact on overall survival (OS), evidenced by a reduction in OS from 28.6 to 8.5 months (univariate: p = 0.002; multivariable: p = 0.043). Additionally, a marked enhancement in sensitivity was achieved (by around 3-4-times) compared to peripheral blood (PB) samples, with positive predictive values for OS being preserved at around 90%. Prognostic relevance of CS-CTCs in PDAC was further validated in PB-samples from 228 PDAC patients, consolidating the established association between CTC-presence and reduced OS (8.5 vs. 19.0 months, p < 0.001). In conclusion, DLA-derived CS-CTCs may serve as a viable tool for identifying high-risk PDAC-patients and aiding the optimization of multimodal treatment strategies. Moreover, DLA enables comprehensive diagnostic profiling by providing ample CTC material, reinforcing its utility as a reliable liquid-biopsy approach. This high-volume liquid-biopsy strategy presents a potential pathway for enhancing clinical management in this malignancy.

In Vitro Analysis of the Effect of SARS-CoV-2 Non-VOC and four Variants of Concern on MHC-Class-I Expression on Calu-3 and Caco-2 Cells.

As the MHC-I-pathway is key to antigen presentation to cytotoxic T-cells and, therefore, recognition by the host adaptive immune system, we hypothesized that SARS-CoV-2 including its Variants of Concern (VOCs), influences MHC-I expression on epithelial cell surfaces as an immune evasion strategy. We conducted an in vitro time course experiment with the human airway epithelial cell line Calu-3 and the human colorectal adenocarcinoma cell line Caco-2. Cells were infected with SARS-CoV-2 strains non-VOC/B.1.1, Alpha/B.1.1.7, Beta/B.1.351, Gamma/P.1, and Delta/B.1.617.2. At 2, 24, 48 and 72 h post-infection we performed RT-qPCR to track viral replication. Simultaneously, we performed intracellular staining with a serum of a double-vaccinated healthy adult containing a high amount of spike protein antibody. In flow cytometry experiments, we differentiated between infected (spike protein positive) and bystander (spike protein negative) cells. To compare their HLA expression levels, cells were stained extracellularly with anti-HLA-A-IgG and anti-HLA-B,C-IgG. While HLA-A expression was stable on infected Calu-3 cells for all variants, it increased to different degrees on bystander cells in samples infected with VOCs Beta, Gamma, Delta, or non-VOC over the time course analyzed. In contrast, HLA-A levels were stable in bystander Calu-3 cells in samples infected with the Alpha variant. The upregulation of MHC-I on spike protein negative bystander cells in Calu-3 cell cultures infected with Beta, Gamma, Delta, and partly non-VOC might suggest that infected cells are still capable of secreting inflammatory cytokines like type-I interferons stimulating the MHC-I expression on bystander cells. In comparison, there was no distinct effect on HLA expression level on Caco-2 cells of any of the VOCs or non-VOC. Further investigations of the full range of immune evasion strategies of SARS-CoV-2 variants are warranted.

Sequence diversity of hepatitis D virus in Mongolia.

Introduction: The Hepatitis Delta Virus (HDV) is a defective, single-stranded RNA virusoid encoding for a single protein, the Hepatitis Delta Antigen (HDAg), which requires the hepatitis B virus (HBV) envelope protein (HBsAg) for its transmission. Currently, hepatitis D is the most aggressive form of viral hepatitis and treatment options are limited. Worldwide 12 million people are chronically infected with HDV being at high risk for progression to cirrhosis and development of liver cancer. Objectives: Although it is well established that Mongolia is the country with the highest prevalence of HDV infections, the information on the molecular epidemiology and factors contributing to HDV sequence diversity are largely unclear. The aim of the study was to characterize the sequence diversity of HDV in rural areas from Mongolia and to determine the extent of HLA class I-associated selection pressure. Patients and methods: From the HepMongolia cohort from rural areas in Mongolia, 451 HBsAg-positive individuals were selected and anti-HDV, HDV-RNA and the sequence of the large HDAg was determined. For all individuals the HLA class I locus was genotyped. Residues under selection pressure in the presence of individual HLA class I types were identified with the recently published analysis tool HAMdetector. Results: Of 431 HBsAg positive patients, 281 were anti-HDV positive (65%), and HDV-RNA could be detected in 207 of 281 (74%) of patients. The complete large HDAg was successfully sequenced from 131 samples. Phylogenetic analysis revealed that all Mongolian HDV isolates belong to genotype 1, however, they separate into several different clusters without clear regional association. In turn, from phylogeny there is strong evidence for recent local transmission events. Importantly, we found multiple residues with strong support for HLA class I-associated selection pressure consistent with a functional CD8+ T cell response directed against HDV. Conclusion: HDV isolates from Mongolia are highly diverse. The molecular epidemiology suggests circulation of multiple subtypes and provides evidence for ongoing recent transmissions.

In-depth virological and immunological characterization of HIV-1 cure after CCR5Δ32/Δ32 allogeneic hematopoietic stem cell transplantation.

Despite scientific evidence originating from two patients published to date that CCR5Δ32/Δ32 hematopoietic stem cell transplantation (HSCT) can cure human immunodeficiency virus type 1 (HIV-1), the knowledge of immunological and virological correlates of cure is limited. Here we characterize a case of long-term HIV-1 remission of a 53-year-old male who was carefully monitored for more than 9 years after allogeneic CCR5Δ32/Δ32 HSCT performed for acute myeloid leukemia. Despite sporadic traces of HIV-1 DNA detected by droplet digital PCR and in situ hybridization assays in peripheral T cell subsets and tissue-derived samples, repeated ex vivo quantitative and in vivo outgrowth assays in humanized mice did not reveal replication-competent virus. Low levels of immune activation and waning HIV-1-specific humoral and cellular immune responses indicated a lack of ongoing antigen production. Four years after analytical treatment interruption, the absence of a viral rebound and the lack of immunological correlates of HIV-1 antigen persistence are strong evidence for HIV-1 cure after CCR5Δ32/Δ32 HSCT.

Identification of new RAD51D-regulating microRNAs that also emerge as potent inhibitors of the Fanconi anemia/homologous recombination pathways.

The Fanconi anemia (FA) and homologous recombination (HR) pathways, which partially overlap and include RAD51 and its paralogs, are key for the repair of different types of DNA damage, such as DNA interstrand crosslinks. First, to broadly assess the impact of microRNA-mediated regulation, we examined microRNA expression profiles in five isogenic fibroblast cell pairs, either deficient in DNA repair due to germline mutations in FANCA, FANCB, FANCC, FANCI or BRIP1/FANCJ or proficient due to correction with retroviral vectors. In each pair, we observed lower abundance of specific microRNAs in the FA-deficient cells. From the list of microRNAs, we experimentally confirmed the effects of miR-141-3p and miR-369-3p targeting RAD51B and miR-15a-5p, miR-494-3p as well as miR-544a targeting RAD51D. However, by western blotting, only RAD51D protein was reduced by a mixture of its regulating microRNAs. Gene ontology analyses and identification of additional FA/HR factors as targets of miR-15a-5p, miR-494-3p and miR-544a strongly suggested the widespread influence of these microRNAs on HR. Interestingly, only miR-494-3p directly reduced RAD51 foci formation, while a mixture of miR-15a-5p, miR-494-3p and miR-544a strongly reduced HR activity in green fluorescent protein (GFP) repair assays. In summary, by successfully employing this novel loss- and gain-of-function strategy, we have identified new microRNAs strongly inhibiting HR in mammalian cells. Understanding and modulating such miRNA regulation of DNA repair genes/pathways might help to overcome the reduced repair capacity of FA patients with biallelic hypomorphic mutations or help to engineer synthetic lethality strategies for patients with mutations in cancer-associated FA/HR genes.

The Effect of Pre-Thyroidectomy Calcitriol Prophylaxis on Post-Thyroidectomy Hypocalcaemia in Children.

INTRODUCTION: Transient or persistent hypoparathyroidism is one of the most well-known complications of total thyroidectomy and may lead to symptomatic hypocalcaemia. In children, treatment of post-thyroidectomy hypocalcaemia usually consists of postoperative calcium and/or vitamin D supplementation. In 2013, we implemented prophylactic pre-thyroidectomy calcitriol supplementation for all children undergoing total thyroidectomy at the Amsterdam UMC. The objective of this study was to evaluate the efficacy of this prophylactic calcitriol supplementation in preventing post-thyroidectomy hypocalcaemia in children. METHODS: In a retrospective case study, we included all children (age <18 years), who underwent a total or completion thyroidectomy in the Amsterdam UMC, between 2000 and 2020. Patients were divided into two groups, patients with preoperative calcitriol supplementation and those without (controls). Hypocalcaemia was defined as total serum calcium concentration of <2.0 mmol/L. The primary outcome measure was the occurrence of hypocalcaemia in the first 72 h after surgery. Secondary outcome measures were occurrence of symptomatic hypocalcaemia, need for medical intervention within the first 72 h after surgery, and length of hospitalization. RESULTS: A total of 51 patients were included; 26 with calcitriol prophylaxis and 25 controls. There was no significant difference in occurrence of hypocalcaemia (17/26 prophylaxis group; 18/25 control group). Median postoperative calcium concentrations in the first 72 h were significantly higher in the group with prophylaxis at 30-35 h (2.26 vs. 2.01 mmol/L) and 36-41 h (2.17 vs. 1.92 mmol/L). Occurrence of symptomatic hypocalcaemia, need for medical intervention, and length of hospitalization were not significantly different between the groups. CONCLUSION: Calcitriol prophylaxis resulted in somewhat higher postoperative calcium concentrations but did not reduce the occurrence of hypocalcaemia or affect clinical outcome measures such as occurrence of symptomatic hypocalcaemia and length of postoperative hospitalization.

Reconvalescent plasma/camostat mesylate in early SARS-CoV-2 Q-PCR positive high-risk individuals (RES-Q-HR): a structured summary of a study protocol for a randomized controlled trial.

OBJECTIVES: Currently, there are no approved treatments for early disease stages of COVID-19 and few strategies to prevent disease progression after infection with SARS-CoV-2. The objective of this study is to evaluate the safety and efficacy of convalescent plasma (CP) or camostat mesylate administered within 72 h of diagnosis of SARS-CoV-2 infection in adult individuals with pre-existing risk factors at higher risk of getting seriously ill with COVID-19. Camostat mesylate acts as an inhibitor of the host cell serine protease TMPRSS2 and prevents the virus from entering the cell. CP represents another antiviral strategy in terms of passive immunization. The working hypothesis to be tested in the RES-Q-HR study is that the early use of CP or camostat mesylate reduces the likelihood of disease progression to (modified) WHO stages 4b-8 in SARS-CoV-2-positive adult patients at high risk of moderate or severe COVID-19 progression. TRIAL DESIGN: This study is a 4-arm (parallel group), multicenter, randomized (2:2:1:1 ratio), partly double-blind, controlled trial to evaluate the safety and efficacy of convalescent plasma (CP) or camostat mesylate with control or placebo in adult patients diagnosed with SARS-CoV-2 infection and high risk for progression to moderate/severe COVID-19. Superiority of the intervention arms will be tested. PARTICIPANTS: The trial is conducted at 10-15 tertiary care centers in Germany. Individuals aged 18 years or above with ability to provide written informed consent with SARS-CoV-2 infection, confirmed by PCR within 3 days or less before enrolment and the presence of at least one SARS-CoV-2 symptom (such as fever, cough, shortness of breath, sore throat, headache, fatigue, smell/and or taste disorder, diarrhea, abdominal symptoms, exanthema) and symptom duration of not more than 3 days. Further inclusion criteria comprise: Presence of at least one of the following criteria indicating increased risk for severe COVID-19: Age > 75 years Chronic obstructive pulmonary disease (COPD) and/or pulmonary fibrosis BMI > 40 kg/m2 Age > 65 years with at least one other risk factor (BMI > 35 kg/m2, coronary artery disease (CAD), chronic kidney disease (CKD) with GFR < 60 ml/min but ≥ 30 ml/min, diabetes mellitus, active tumor disease) BMI > 35 kg/m2 with at least one other risk factor (CAD, CKD with GFR < 60 ml/min but ≥ 30 ml/min, diabetes mellitus, active tumor disease) Exclusion criteria: 1. Age < 18 years 2. Unable to give informed consent 3. Pregnant women or breastfeeding mothers 4. Previous transfusion reaction or other contraindication to a plasma transfusion 5. Known hypersensitivity to camostat mesylate and/or severe pancreatitis 6. Volume stress due to CP administration would be intolerable 7. Known IgA deficiency 8. Life expectancy < 6 months 9. Duration SARS-CoV-2 typical symptoms > 3 days 10. SARS-CoV-2 PCR detection older than 3 days 11. SARS-CoV-2 associated clinical condition ≥ WHO stage 3 (patients hospitalized for other reasons than COVID-19 may be included if they fulfill all inclusion and none of the exclusion criteria) 12. Previously or currently hospitalized due to SARS-CoV-2 13. Previous antiviral therapy for SARS-CoV-2 14. ALT or AST > 5 x ULN at screening 15. Liver cirrhosis > Child A (patients with Child B/C cirrhosis are excluded from the trial) 16. Chronic kidney disease with GFR < 30 ml/min 17. Concurrent or planned anticancer treatment during trial period 18. Accommodation in an institution due to legal orders (§40(4) AMG). 19. Any psycho-social condition hampering compliance with the study protocol. 20. Evidence of current drug or alcohol abuse 21. Use of other investigational treatment within 5 half-lives of enrolment is prohibited 22. Previous use of convalescent plasma for COVID-19 23. Concomitant proven influenza A infection 24. Patients with organ or bone marrow transplant in the three months prior to screening visit INTERVENTION AND COMPARATOR: Participants will be randomized to the following 4 groups: 1) Convalescent plasma (CP), 2 units at screening/baseline visit (day 0) or day 1; CP is defined by the presence of neutralizing anti-SARS-CoV-2 antibodies with titers ≥ 1:160; individuals with body weight ≥ 150 kg will receive a third unit of plasma on day 3 2) Camostat mesylate (200 mg per capsule, one capsule taken each in the morning, afternoon and evening on days 1-7) 3) Standard of care (SOC, control for CP) 4) Placebo (identical in appearance to camostat mesylate capsules, one capsule taken each morning, afternoon and evening on days 1-7; for camostat mesylate control group) Participants will be monitored after screening/baseline on day 3, day 5, day 8, and day 14. On day 28 and day 56, telephone visits and on day 90, another outpatient visit are scheduled. Adverse events and serious adverse events will be monitored and reported until the end of the study. An independent data safety monitoring committee will review trial progression and safety. MAIN OUTCOMES: The primary endpoint of the study is the cumulative number of individuals who progress to or beyond category 4b on the modified WHO COVID-19 ordinal scale (defined as hospitalization with COVID-19 pneumonia and additional oxygen demand via nasal cannula or mask) within 28 days after randomization. RANDOMIZATION: Participants will be randomized using the Alea-Tool ( aleaclinical.com ) in a 2:2:1:1 ratio to the treatment arms (1) CP, (2) camostat mesylate, (3) standard of care (SoC), and (4) placebo matching camostat mesylate. Randomization will be stratified by study center. BLINDING (MASKING): The camostat mesylate treatment arm and the respective placebo will be blinded for participants, caregivers, and those assessing outcomes. The treatment arms convalescent plasma and standard of care will not be blinded and thus are open-labeled, unblinded. NUMBERS TO BE RANDOMIZED (SAMPLE SIZE): Overall, n = 994 participants will be randomized to the following groups: n = 331 to convalescent plasma (CP), n = 331 to camostat mesylate, n = 166 to standard of care (SoC), and n = 166 to placebo matching camostat mesylate. TRIAL STATUS: The RES-Q-HR protocol (V04F) was approved on the 18 December 2020 by the local ethics committee and by the regulatory institutions PEI/BfARM on the 2 December 2020. The trial was opened for recruitment on 26 December 2020; the first patient was enrolled on 7 January 2021 and randomized on 8 January 2021. Recruitment shall be completed by June 2021. The current protocol version RES-Q HR V05F is from 4 January 2021, which was approved on the 18 January 2021. TRIAL REGISTRATION: EudraCT Number 2020-004695-18 . Registered on September 29, 2020. ClinicalTrial.gov NCT04681430 . Registered on December 23, 2020, prior to the start of the enrollment (which was opened on December 26, 2020). FULL PROTOCOL: The full protocol (V05F) is attached as an additional file, accessible from the Trials website (Additional file 1). In the interest in expediting dissemination of this material, the familiar formatting has been eliminated; this letter serves as a summary of the key elements of the full protocol. The study protocol has been reported in accordance with the Standard Protocol Items: Recommendations for Clinical Interventional Trials (SPIRIT) guidelines (Additional file 2).

CD33 Delineates Two Functionally Distinct NK Cell Populations Divergent in Cytokine Production and Antibody-Mediated Cellular Cytotoxicity.

The generation and expansion of functionally competent NK cells in vitro is of great interest for their application in immunotherapy of cancer. Since CD33 constitutes a promising target for immunotherapy of myeloid malignancies, NK cells expressing a CD33-specific chimeric antigen receptor (CAR) were generated. Unexpectedly, we noted that CD33-CAR NK cells could not be efficiently expanded in vitro due to a fratricide-like process in which CD33-CAR NK cells killed other CD33-CAR NK cells that had upregulated CD33 in culture. This upregulation was dependent on the stimulation protocol and encompassed up to 50% of NK cells including CD56dim NK cells that do generally not express CD33 in vivo. RNAseq analysis revealed that upregulation of CD33+ NK cells was accompanied by a unique transcriptional signature combining features of canonical CD56bright (CD117high, CD16low) and CD56dim NK cells (high expression of granzyme B and perforin). CD33+ NK cells exhibited significantly higher mobilization of cytotoxic granula and comparable levels of cytotoxicity against different leukemic target cells compared to the CD33- subset. Moreover, CD33+ NK cells showed superior production of IFNγ and TNFα, whereas CD33- NK cells exerted increased antibody-dependent cellular cytotoxicity (ADCC). In summary, the study delineates a novel functional divergence between NK cell subsets upon in vitro stimulation that is marked by CD33 expression. By choosing suitable stimulation protocols, it is possible to preferentially generate CD33+ NK cells combining efficient target cell killing and cytokine production, or alternatively CD33- NK cells, which produce less cytokines but are more efficient in antibody-dependent applications.

Aging-associated distinctive DNA methylation changes of LINE-1 retrotransposons in pure cell-free DNA from human blood.

LINE-1 hypomethylation of cell-free DNA has been described as an epigenetic biomarker of human aging. However, in the past, insufficient differentiation between cellular and cell-free DNA may have confounded analyses of genome-wide methylation levels in aging cells. Here we present a new methodological strategy to properly and unambiguously extract DNA methylation patterns of repetitive, as well as single genetic loci from pure cell-free DNA from peripheral blood. Since this nucleic acid fraction originates mainly in apoptotic, senescent and cancerous cells, this approach allows efficient analysis of aged and cancerous cell-specific DNA methylation patterns for diagnostic and prognostic purposes. Using this methodology, we observe a significant age-associated erosion of LINE-1 methylation in cfDNA suggesting that the threshold of hypomethylation sufficient for relevant LINE-1 activation and consequential harmful retrotransposition might be reached at higher age. We speculate that this process might contribute to making aging the main risk factor for many cancers.

Measures of infection prevention and incidence of SARS-CoV-2 infections in cancer patients undergoing radiotherapy in Germany, Austria and Switzerland.

PURPOSE: COVID-19 infection has manifested as a major threat to both patients and healthcare providers around the world. Radiation oncology institutions (ROI) deliver a major component of cancer treatment, with protocols that might span over several weeks, with the result of increasing susceptibility to COVID-19 infection and presenting with a more severe clinical course when compared with the general population. The aim of this manuscript is to investigate the impact of ROI protocols and performance on daily practice in the high-risk cancer patients during this pandemic. METHODS: We addressed the incidence of positive COVID-19 cases in both patients and health care workers (HCW), in addition to the protective measures adopted in ROIs in Germany, Austria and Switzerland using a specific questionnaire. RESULTS: The results of the questionnaire showed that a noteworthy number of ROIs were able to complete treatment in SARS-CoV­2 positive cancer patients, with only a short interruption. The ROIs reported a significant decrease in patient volume that was not impacted by the circumambient disease incidence, the type of ROI or the occurrence of positive cases. Of the ROIs 16.5% also reported infected HCWs. About half of the ROIs (50.5%) adopted a screening program for patients whereas only 23.3% also screened their HCWs. The range of protective measures included the creation of working groups, instituting home office work and protection with face masks. Regarding the therapeutic options offered, curative procedures were performed with either unchanged or moderately decreased schedules, whereas palliative or benign radiotherapy procedures were more often shortened. Most ROIs postponed or cancelled radiation treatment for benign indications (88.1%). The occurrence of SARS-CoV­2 infections did not affect the treatment options for curative procedures. Non-university-based ROIs seemed to be more willing to change their treatment options for curative and palliative cases than university-based ROIs. CONCLUSION: Most ROIs reported a deep impact of SARS-CoV­2 infections on their work routine. Modification and prioritization of treatment regimens and the application of protective measures preserved a well-functioning radiation oncology service and patient care.

Diagnostic Leukapheresis Enables Reliable Transcriptomic Profiling of Single Circulating Tumor Cells to Characterize Inter-Cellular Heterogeneity in Terms of Endocrine Resistance.

Circulating tumor cells (CTCs) hold great promise with regard to prognosis, treatment optimization, and monitoring of breast cancer patients. Single CTC transcriptome profiling might help reveal valuable information concerning intra-patient heterogeneity relevant to therapeutic interventions. In this study, we combined Diagnostic Leukapheresis (DLA), which is a microfluidic enrichment using the ParsortixTM system, micromanipulation with CellCelectorTM and subsequent single cell multi-marker transcriptome profiling. First, a PCR panel consisting of 30 different endocrine resistance and phenotypic marker genes was validated for single cell profiling by using different breast cancer cell lines. Second, this panel was applied to characterize uncultured and cultured CTCs, which were enriched from a cryopreserved DLA product obtained from a patient suffering from metastatic breast cancer resistant to endocrine therapy. Gene expression profiles of both CTC populations uncovered inter CTC heterogeneity for transcripts, which are associated with response or resistance to endocrine therapy (e.g., ESR1, HER2, FGFR1). Hierarchical clustering revealed CTC subpopulations with different expressions of transcripts regarding the CTCs' differential phenotypes (EpCAM, CD44, CD24, MYC, MUC1) and of transcripts involved in endocrine signaling pathways (FOXO, PTEN). Moreover, ER-positive CTCs exhibited significant higher expression of Cyclin D1, which might be relevant for CDK4/6 inhibitor therapies. Overall, gene expression profiles of uncultured and cultured CTCs resulted in a partly combined grouping. Our findings demonstrate that multi-marker RNA profiling of enriched single uncultured CTCs and cultured CTCs form cryopreserved DLA samples may provide important insights into intra-patient heterogeneity relevant for targeted therapies and therapy resistance.

From in vitro to ex vivo: subcellular localization and uptake of graphene quantum dots into solid tumors.

Among various nanoparticles tested for pharmacological applications over the recent years, graphene quantum dots (GQDs) seem to be promising candidates for the construction of drug delivery systems due to their superior biophysical and biochemical properties. The subcellular fate of incorporated nanomaterial is decisive for transporting pharmaceuticals into target cells. Therefore a detailed characterization of the uptake of GQDs into different breast cancer models was performed. The demonstrated accumulation inside the endolysosomal system might be the reason for the particles' low toxicity, but has to be overcome for cytosolic or nuclear drug delivery. Furthermore, the penetration of GQDs into precision-cut mammary tumor slices was studied. These constitute a far closer to reality model system than monoclonal cell lines. The constant uptake into the depth of the tissue slices underlines the systems' potential for drug delivery into solid tumors.

Label-Free Enrichment and Molecular Characterization of Viable Circulating Tumor Cells from Diagnostic Leukapheresis Products.

INTRODUCTION: Circulating tumor cells (CTCs) may be used to improve cancer diagnosis, prognosis, and treatment. However, because knowledge regarding CTC biology is limited and the numbers of CTCs and CTC-positive cancer patients are low, progress in this field is slow. We addressed this limitation by combining diagnostic leukapheresis (DLA) and microfluidic enrichment to obtain large numbers of viable CTCs from metastasized breast cancer patients. METHODS: DLA was applied to 9 patients, and 7.5 mL of peripheral blood was drawn. CTCs were enriched with the Parsortix™ system. The quality of CTCs from fresh and cryopreserved DLA products was tested, and CTCs were cultured in vitro. Single uncultured and cultured CTCs were isolated by micromanipulation to determine different parameters, such as genomic aberrations and mutation profiles of selected tumor-associated genes. Expression levels of estrogen receptor and HER2/neu were monitored during in vitro culture. RESULTS: Viable CTCs from peripheral blood and fresh or frozen DLA products could be enriched. DLA increased the likelihood of successful CTC culture. Cryopreserved DLA products could be stored with minimal CTC loss and no overt reduction in the tumor cell quality and viability during an observation period of up to 3 years. The analyzed parameters did not change during in vitro culture. DLA samples with high CTC numbers and lower ratios of apoptotic CTCs were more likely to grow in culture. CONCLUSIONS: The increased CTC numbers from fresh or cryopreserved DLA products facilitate multiple functional and molecular analyses and, thus, could improve our knowledge of their biology.

Biomechanical Stability and Osteogenesis in a Tibial Bone Defect Treated by Autologous Ovine Cord Blood Cells-A Pilot Study.

The aim of this study was to elucidate the impact of autologous umbilical cord blood cells (USSC) on bone regeneration and biomechanical stability in an ovine tibial bone defect. Ovine USSC were harvested and characterized. After 12 months, full-size 2.0 cm mid-diaphyseal bone defects were created and stabilized by an external fixateur containing a rigidity measuring device. Defects were filled with (i) autologous USSC on hydroxyapatite (HA) scaffold (test group), (ii) HA scaffold without cells (HA group), or (iii) left empty (control group). Biomechanical measures, standardized X-rays, and systemic response controls were performed regularly. After six months, bone regeneration was evaluated histomorphometrically and labeled USSC were tracked. In all groups, the torsion distance decreased over time, and radiographies showed comparable bone regeneration. The area of newly formed bone was 82.5 ± 5.5% in the control compared to 59.2 ± 13.0% in the test and 48.6 ± 2.9% in the HA group. Labeled cells could be detected in lymph nodes, liver and pancreas without any signs of tumor formation. Although biomechanical stability was reached earliest in the test group with autologous USSC on HA scaffold, the density of newly formed bone was superior in the control group without any bovine HA.

Diagnostic leukapheresis for CTC analysis in breast cancer patients: CTC frequency, clinical experiences and recommendations for standardized reporting.

Diagnostic leukapheresis (DLA) is based on continuous centrifugation that collects mononuclear cells from peripheral blood with a density of 1.055-1.08 g/ml. As epithelial cells have a similar density, DLA cocollects circulating tumor cell (CTCs) along with the targeted mononuclear cells. Here, we report on our single center experience applying DLA in 40 nonmetastatic and metastatic breast cancer patients and its impact on CTC detection. We found that the use of just 5% of the DLA product (corresponding to a median peripheral blood volume of around 60 ml) in the CellSearch® assay already leads to a significant increase in CTC detection frequency and yield. The implementation of the method was unproblematic, and we did not observe any adverse events in our patient cohort. Extrapolating the CTC counts in the DLA samples to the whole DLA product indicated that enormous CTC numbers could be harvested by this approach (around 205x more CTCs than in the 7.5 ml blood sample in M1 patients). In conclusion, DLA is a clinically safe method to collect CTCs from liters of blood enabling a real liquid biopsy. Yet, further technical developments are required to process whole DLA products and exploit the full potential of this approach. As it is foreseeable that DLA will be used by several groups, and hopefully ultimately brought to the patients in a routine setting, we discuss recommendations on the minimum of required information for reporting on DLAs to allow comparison across different approaches. © 2018 International Society for Advancement of Cytometry.

Genome-wide hypomethylation of LINE-1 and Alu retroelements in cell-free DNA of blood is an epigenetic biomarker of human aging.

Aging associated DNA hypomethylation of LINE-1 and Alu retroelements may be a crucial determinant of loss of genomic integrity, deterioration and cancer. In peripheral blood LINE-1 hypomethylation has been reported to increase during aging, but other studies did not observe significant changes. We hypothesized that these apparently inconsistent reports might relate to differences between cellular and cell-free DNA. Using the technique of idiolocal normalization of real-time methylation-specific PCR (IDLN-MSP) for genetic imbalanced DNA specimens we obtained evidence that LINE-1 hypomethylation in cell-free DNA, but not cellular DNA from peripheral blood is an epigenetic biomarker for human aging. Furthermore, hypomethylation of cell-free DNA is more extensive in smokers, suggesting that it might be used as a surrogate marker for monitoring the improvement of smoking-induced adverse effects after cancelling smoking.

Toward a real liquid biopsy in metastatic breast and prostate cancer: Diagnostic LeukApheresis increases CTC yields in a European prospective multicenter study (CTCTrap).

Frequently, the number of circulating tumor cells (CTC) isolated in 7.5 mL of blood is too small to reliably determine tumor heterogeneity and to be representative as a "liquid biopsy". In the EU FP7 program CTCTrap, we aimed to validate and optimize the recently introduced Diagnostic LeukApheresis (DLA) to screen liters of blood. Here we present the results obtained from 34 metastatic cancer patients subjected to DLA in the participating institutions. About 7.5 mL blood processed with CellSearch® was used as "gold standard" reference. DLAs were obtained from 22 metastatic prostate and 12 metastatic breast cancer patients at four different institutions without any noticeable side effects. DLA samples were prepared and processed with different analysis techniques. Processing DLA using CellSearch resulted in a 0-32 fold increase in CTC yield compared to processing 7.5 mL blood. Filtration of DLA through 5 µm pores microsieves was accompanied by large CTC losses. Leukocyte depletion of 18 mL followed by CellSearch yielded an increase of the number of CTC but a relative decrease in yield (37%) versus CellSearch DLA. In four out of seven patients with 0 CTC detected in 7.5 mL of blood, CTC were detected in DLA (range 1-4 CTC). The CTC obtained through DLA enables molecular characterization of the tumor. CTC enrichment technologies however still need to be improved to isolate all the CTC present in the DLA.

Isolation of circulating tumor cells from pancreatic cancer by automated filtration.

It is now widely recognized that the isolation of circulating tumor cells based on cell surface markers might be hindered by variability in their protein expression. Especially in pancreatic cancer, isolation based only on EpCAM expression has produced very diverse results. Methods that are independent of surface markers and therefore independent of phenotypical changes in the circulating cells might increase CTC recovery also in pancreatic cancer. We compared an EpCAM-dependent (IsoFlux) and a size-dependent (automated Siemens Healthineers filtration device) isolation method for the enrichment of pancreatic cancer CTCs. The recovery rate of the filtration based approach is dramatically superior to the EpCAM-dependent approach especially for cells with low EpCAM-expression (filtration: 52%, EpCAM-dependent: 1%). As storage and shipment of clinical samples is important for centralized analyses, we also evaluated the use of frozen diagnostic leukapheresis (DLA) as source for isolating CTCs and subsequent genetic analysis such as KRAS mutation detection analysis. Using frozen DLA samples of pancreatic cancer patients we detected CTCs in 42% of the samples by automated filtration.

Disseminated tumour cells with highly aberrant genomes are linked to poor prognosis in operable oesophageal adenocarcinoma.

BACKGROUND: Chromosomal instability (CIN) has repeatedly been identified as a prognostic marker. Here we evaluated the percentage of aberrant genome per cell (PAG) as a measure of CIN in single disseminated tumour cells (DTC) isolated from patients with operable oesophageal adenocarcinoma (EAC), to assess the impact of CINhigh DTCs on prognosis. METHODS: We isolated CK18positive DTCs from bone marrow (BM) or lymph node (LN) preparations of operable EAC patients. After whole-genome amplification, single DTCs were analysed for chromosomal gains and losses using metaphase-based comparative genomic hybridisation (mCGH). We calculated the PAG for each DTC and determined the critical threshold value that identifies high-risk patients by STEPP (Subpopulation Treatment Effect Pattern Plot) analysis in two independent EAC patient cohorts (cohort #1, n=44; cohort #2; n=29). RESULTS: The most common chromosomal alterations observed among the DTCs were typical for EAC, but the DTCs showed a varying PAG between individual patients. Generally, LNDTCs displayed a significantly higher PAG than BMDTCs. STEPP analysis revealed an increasing PAG of DTCs to be correlated with an increased risk for short survival in two independent EAC cohorts as well as in the corresponding pooled analysis. In all three data sets (cohort #1, cohort #2 and pooled cohort), PAGhigh DTCs conferred an independent risk for a significantly decreased survival. CONCLUSIONS: The analysis of PAG/CIN in solitary marker-positive DTCs identifies operable EAC patients with poor prognosis, indicating a more aggressive minimal residual disease.

Recipient HLA-C Haplotypes and microRNA 148a/b Binding Sites Have No Impact on Allogeneic Hematopoietic Cell Transplantation Outcomes.

Natural killer cells are important in graft-versus-leukemia responses after hematopoietic cell transplantation (HCT). A variety of surface receptors dictates natural killer cell function, including killer cell immunoglobulin-like receptor recognition of HLA-C. Previous single-center studies show that HLA-C epitopes, designated C1 and C2, were associated with allogeneic HCT outcomes; specifically, recipients homozygous for the C1 epitope (C1/C1) experienced a survival benefit. Additionally, mismatching at HLA-C was beneficial in recipients possessing at least 1 C2 allele, whereas the opposite was true for homozygous C1 (C1/C1) recipients where HLA-C mismatching resulted in worse outcomes. In this analysis we aimed to validate these findings in a large multicenter study. We also set out to determine whether surface expression of recipient HLA-C, determined by polymorphism in a microRNA (miR-148a/b) binding site within the 3'-region of the HLA-C transcript, was associated with transplant outcomes. In this large registry cohort, we were unable to confirm the prior findings regarding recipient HLA-C epitope status and outcome. Additionally, HLA-C surface expression (ie, surface density), as predicted by the miR-148a/b binding single nucleotide polymorphism, was also not with associated transplant outcomes. Collectively, neither HLA-C surface expression, as determined by miR-148a/b, nor recipient HLA-C epitopes (C1, C2) are associated with allogeneic HCT outcomes.