GEMA-An Automatic Segmentation Method for Real-Time Analysis of Mammalian Cell Growth in Microfluidic Devices.

Nowadays, image analysis has a relevant role in most scientific and research areas. This process is used to extract and understand information from images to obtain a model, knowledge, and rules in the decision process. In the case of biological areas, images are acquired to describe the behavior of a biological agent in time such as cells using a mathematical and computational approach to generate a system with automatic control. In this paper, MCF7 cells are used to model their growth and death when they have been injected with a drug. These mammalian cells allow understanding of behavior, gene expression, and drug resistance to breast cancer. For this, an automatic segmentation method called GEMA is presented to analyze the apoptosis and confluence stages of culture by measuring the increase or decrease of the image area occupied by cells in microfluidic devices. In vitro, the biological experiments can be analyzed through a sequence of images taken at specific intervals of time. To automate the image segmentation, the proposed algorithm is based on a Gabor filter, a coefficient of variation (CV), and linear regression. This allows the processing of images in real time during the evolution of biological experiments. Moreover, GEMA has been compared with another three representative methods such as gold standard (manual segmentation), morphological gradient, and a semi-automatic algorithm using FIJI. The experiments show promising results, due to the proposed algorithm achieving an accuracy above 90% and a lower computation time because it requires on average 1 s to process each image. This makes it suitable for image-based real-time automatization of biological lab-on-a-chip experiments.

Metronomic doses and drug schematic combination response tested within chambered coverslips for the treatment of breast cancer cells (JIMT-1).

Low-dose metronomic (LDM) chemotherapy is an alternative to conventional chemotherapy and is the most frequently used approach in low dose chemotherapy regimens. The selection of patients, drug dosages, and dosing intervals in LDM is empirical. In this study, we systematically examined the schedule-dependent interaction of drugs on a breast cancer cell line (BCC) cultured in chambered coverslips. The LDM studies were combined with cell staining in order to better characterize different cell states and cell death modes, including caspase-dependent apoptosis, caspase-independent cell death and autophagy-dependent cell death. Microscope images were examined using the Fiji Trainable Weka Segmentation plugin to analyse cell area in 7500 images showing different modes of cell death. Paclitaxel combined with LDM chemotherapy demonstrated a reduction in the area covered by live cells. In contrast, there was an induction of high levels of cell death due to caspase-dependent apoptosis.

Learning deep features for dead and living breast cancer cell classification without staining.

Automated cell classification in cancer biology is a challenging topic in computer vision and machine learning research. Breast cancer is the most common malignancy in women that usually involves phenotypically diverse populations of breast cancer cells and an heterogeneous stroma. In recent years, automated microscopy technologies are allowing the study of live cells over extended periods of time, simplifying the task of compiling large image databases. For instance, there have been several studies oriented towards building machine learning systems capable of automatically classifying images of different cell types (i.e. motor neurons, stem cells). In this work we were interested in classifying breast cancer cells as live or dead, based on a set of automatically retrieved morphological characteristics using image processing techniques. Our hypothesis is that live-dead classification can be performed without any staining and using only bright-field images as input. We tackled this problem using the JIMT-1 breast cancer cell line that grows as an adherent monolayer. First, a vast image set composed by JIMT-1 human breast cancer cells that had been exposed to a chemotherapeutic drug treatment (doxorubicin and paclitaxel) or vehicle control was compiled. Next, several classifiers were trained based on well-known convolutional neural networks (CNN) backbones to perform supervised classification using labels obtained from fluorescence microscopy images associated with each bright-field image. Model performances were evaluated and compared on a large number of bright-field images. The best model reached an AUC = 0.941 for classifying breast cancer cells without treatment. Furthermore, it reached AUC = 0.978 when classifying breast cancer cells under drug treatment. Our results highlight the potential of machine learning and computational image analysis to build new diagnosis tools that benefit the biomedical field by reducing cost, time, and stimulating work reproducibility. More importantly, we analyzed the way our classifiers clusterize bright-field images in the learned high-dimensional embedding and linked these groups to salient visual characteristics in live-dead cell biology observed by trained experts.

A stochastic model of myeloid cell lineages in hematopoiesis and pathway mutations in acute myeloid leukemia.

A model for hematopoiesis is presented that explicitly includes the erythrocyte, granulocyte, and thrombocyte lineages and their common precursors. A small number of stem cells proliferate and differentiate through different compartments to produce the vast number of blood cells needed every day. Growth factors regulate the proliferation of cells dependent on the current demand. We provide a steady state analysis of the model and rough parameter estimates. Furthermore, we extend the model to include mutations that alter the replicative capacity of cells and introduce differentiation blocks. With these mutations the model develops signs of acute myeloid leukemia.

Favourable outcomes of poor prognosis diffuse large B-cell lymphoma patients treated with dose-dense Rituximab, high-dose Methotrexate and six cycles of CHOP-14 compared to first-line autologous transplantation.

The optimal therapeutic approach for young diffuse large B-cell lymphoma (DLBCL) patients with high-intermediate and high-risk age-adjusted international prognostic index (aaIPI) remains unknown. Hereby we report a 10-year single-centre study of 63 consecutively treated patients. To optimize outcome, two approaches were carried out: Cohort 1 patients received four cycles R-CHOP-21 (rituximab, cyclophosphamide, daunorubicin, vincristine, prednisolone over 21 days) followed by first-line high-dose chemotherapy with autologous stem-cell support (HDCT-ASCT), resulting in 2-year progression-free (PFS) and overall survival (OS) of 60·6% and 67·9%. 39·4% of those patients were not transplanted upfront, mainly due to early progressive disease (24·2%). Cohort 2 patients received an early intensified protocol of six cycles of CHOP-14 (cyclophosphamide, daunorubicin, vincristine, prednisolone over 14 days) with dose-dense rituximab and high-dose methotrexate resulting in promising overall response- (93·3%) and complete remission (90%) rates and sustained survival (2-year PFS and OS: 93·3%). In an intention-to-treat analysis, 2-year PFS (60·6% vs. 93·3%, hazard ratio [HR] 7·2, P = 0·009) and OS (69·7% vs. 93·3%, HR 4·95, P = 0·038) differed significantly, in favour of the early intensified protocol (Cohort 2). In a multivariate Cox-regression model, PFS (HR 8·12, 95% confidence interval [CI] 1·83-35·9, P = 0·006) and OS (HR 5·86, 95% CI 1·28-26·8, P = 0·02) remained superior for Cohort 2 when adjusted for aaIPI3 as the most important prognostic factor. Survival of young poor-prognosis DLBCL patients appears superior after early therapy intensification.

Neutrophil granulocytes recruited upon translocation of intestinal bacteria enhance graft-versus-host disease via tissue damage.

Acute graft-versus-host disease (GVHD) considerably limits wider usage of allogeneic hematopoietic cell transplantation (allo-HCT). Antigen-presenting cells and T cells are populations customarily associated with GVHD pathogenesis. Of note, neutrophils are the largest human white blood cell population. The cells cleave chemokines and produce reactive oxygen species, thereby promoting T cell activation. Therefore, during an allogeneic immune response, neutrophils could amplify tissue damage caused by conditioning regimens. We analyzed neutrophil infiltration of the mouse ileum after allo-HCT by in vivo myeloperoxidase imaging and found that infiltration levels were dependent on the local microbial flora and were not detectable under germ-free conditions. Physical or genetic depletion of neutrophils reduced GVHD-related mortality. The contribution of neutrophils to GVHD severity required reactive oxygen species (ROS) because selective Cybb (encoding cytochrome b-245, beta polypeptide, also known as NOX2) deficiency in neutrophils impairing ROS production led to lower levels of tissue damage, GVHD-related mortality and effector phenotype T cells. Enhanced survival of Bcl-xL transgenic neutrophils increased GVHD severity. In contrast, when we transferred neutrophils lacking Toll-like receptor-2 (TLR2), TLR3, TLR4, TLR7 and TLR9, which are normally less strongly activated by translocating bacteria, into wild-type C57BL/6 mice, GVHD severity was reduced. In humans, severity of intestinal GVHD strongly correlated with levels of neutrophils present in GVHD lesions. This study describes a new potential role for neutrophils in the pathogenesis of GVHD in both mice and humans.

NT-pro-BNP: not the prognostic all-rounder in elderly patients undergoing allogeneic stem cell transplantation.

Allogeneic hematopoietic cell transplantation (HCT) is a curative approach for several diseases predominantly affecting elderly patients. Overall survival is compromised by treatment-related mortality (TRM), GvHD, and relapse. Pretransplant clinical risk indicators in elderly patients qualifying for HCT are highly desirable. Pro-BNP is known as a predictor of death in patients with an increasing variety of clinical conditions and frequently used as a routine parameter for organ complications in the allogeneic transplant setting without well-established scientific evidence. Our hypothesis was that pre-HCT NT-pro-BNP could aid in identifying elderly patients at risk for early mortality. We retrospectively evaluated NT-pro-BNP values in 177 consecutive patients of ≥60 years HCT (2005-2010). In 29.4 % of cases, NT-pro-BNP values were within our institute's normal range (<125 pg/ml). Analysis of different NT-pro-BNP cutoff points by receiver operating characteristics curve for mortality at day +100 revealed no single cutoff value with satisfying specificity and sensitivity. The individual outcome of patients with extremely high NT-pro-BNP values was not associated with an increase in mortality or cardiovascular morbidity. NT-pro-BNP values of patients succumbing to TRM did not differ significantly from those alive or having died of relapse-median 276 vs. 217 pg/ml. In conclusion, pre-HCT NT-pro-BNP was of no convincing prognostic relevance for day 100 mortality.

Anti-tumor activity of a B-cell receptor-targeted peptide in a novel disseminated lymphoma xenograft model.

Receptor-targeted therapies have become standard in the treatment of various lymphomas. In view of its unparalleled specificity for the malignant B-cell clone, the B-cell receptor (BCR) on B cell lymphoma cells is a potential therapeutic target. We have used two BCR epitope mimicking peptides binding to the Burkitt's lymphoma cell lines CA46 and SUP-B8. We proved their functionality by demonstrating calcium flux and BCR-mediated endocytosis upon peptide receptor binding. Toxicity experiments in vitro via cross-linking of the BCR with tetramerized epitope mimics lead to apoptosis in both cell lines but was far more effective in SUP-B8 cells. We established a SUP-B8-based disseminated Burkitt's lymphoma model in NOD/SCID mice. Treatment of tumor-bearing mice with tetramerized epitope mimics had significant anti-tumor effects in vivo. We conclude that peptide-mediated, BCR-targeted therapy is a promising approach which may be explored and further developed for application in highly aggressive lymphoma.

B-cell receptor epitope recognition correlates with the clinical course of chronic lymphocytic leukemia.

BACKGROUND: B-cell receptors (BCRs) and their recognition of specific epitopes may play a pivotal role in the development and progression of chronic lymphocytic leukemia (CLL). In this study, the authors set up a model system to explore epitope reactivity and its clinical relevance in CLL. METHODS: Epitope-mimicking peptides were selected from phage display libraries on 6 CLL BCRs from randomly chosen patients. The binding of the 6 index epitope mimics was evaluated in a set of 100 unrelated CLL samples. Epitope recognition patterns were correlated with the clinical course of the disease. RESULTS: Surprisingly, all CLL samples recognized 1 or several index epitopes, and some revealed marked polyreactivity. Patients with CLL who expressed BCRs that reacted with ≥5 epitope mimics had a significantly worse clinical course than less polyreactive patients (median time to first treatment, 24 months vs 102 months). This effect was independent of otherwise known prognostic markers. CONCLUSIONS: The authors introduced a system with which to model epitope reactivity of CLL BCRs without previous knowledge of potential antigens. The findings indicated that a polyreactive epitope recognition pattern may be a determinant of an aggressive clinical course in this disease. This further emphasizes the functional and prognostic relevance of BCR epitope recognition in CLL.

The microenvironment differentially impairs passive and active immunotherapy in chronic lymphocytic leukaemia - CXCR4 antagonists as potential adjuvants for monoclonal antibodies.

Direct contact with stromal cells protects chronic lymphocytic leukaemia (CLL) B cells from chemotherapy-induced apoptosis in vitro. Blockade of CXCR4 signalling antagonizes stroma-mediated interactions and restores CLL chemosensitivity. In vivo, administration of CXCR4 antagonists effectively mobilizes haematopoietic progenitor cells. Therefore, combinations of CXCR4 blockade and cytoreductive treatment with selective activity on CLL cells may avoid potential haematotoxicity. Hence, we tested CXCR4 antagonists in the context of passive and active immunotherapeutic approaches. We evaluated how efficiently rituximab, alemtuzumab and cytotoxic T cells killed CLL cells cocultured with stromal cells in the presence and absence of a CXCR4 antagonist. Stromal cell contact attenuated rituximab- and alemtuzumab-induced complement-dependent cytotoxicity of CLL cells. Addition of CXCR4 antagonists abrogated the protective effect of stroma. In contrast, stromal cells did not impair antibody-dependent cell-mediated cytotoxicity and cytotoxicity induced by activated T cells. Destruction of microtubules in CLL target cells restored the protective effect of stroma coculture for CLL cells during Natural Killer cell attack by preventing mitochondrial relocalization towards the immunological synapse. Our data identify the combination of CXCR4 antagonists with passive - but not active - immunotherapy as a promising potential treatment concept in CLL.

Six versus eight cycles of bi-weekly CHOP-14 with or without rituximab in elderly patients with aggressive CD20+ B-cell lymphomas: a randomised controlled trial (RICOVER-60).

BACKGROUND: Cyclophosphamide, doxorubicin, vincristine, and prednisolone (CHOP) is used to treat patients with non-Hodgkin lymphoma. Interval decrease from 3 weeks of treatment (CHOP-21) to 2 weeks (CHOP-14), and addition of rituximab to CHOP-21 (R-CHOP-21) has been shown to improve outcome in elderly patients with diffuse large B-cell lymphoma (DLBCL). This randomised trial assessed whether six or eight cycles of R-CHOP-14 can improve outcome of these patients compared with six or eight cycles of CHOP-14. METHODS: 1222 elderly patients (aged 61-80 years) were randomly assigned to six or eight cycles of CHOP-14 with or without rituximab. Radiotherapy was planned to sites of initial bulky disease with or without extranodal involvement. The primary endpoint was event-free survival; secondary endpoints were response, progression during treatment, progression-free survival, overall survival, and frequency of toxic effects. Analyses were done by intention to treat. The trial is registered on National Cancer Institute website, number NCT00052936 and as EU-20243. FINDINGS: 3-year event-free survival was 47.2% after six cycles of CHOP-14 (95% CI 41.2-53.3), 53.0% (47.0-59.1) after eight cycles of CHOP-14, 66.5% (60.9-72.0) after six cycles of R-CHOP-14, and 63.1% (57.4-68.8) after eight cycles of R-CHOP-14. Compared with six cycles of CHOP-14, the improvement in 3-year event-free survival was 5.8% (-2.8-14.4) for eight cycles of CHOP-14, 19.3% (11.1-27.5) for six cycles of R-CHOP-14, and 15.9% (7.6-24.2) for eight cycles of R-CHOP-14. 3-year overall survival was 67.7% (62.0-73.5) for six cycles of CHOP-14, 66.0% (60.1-71.9) for eight cycles of CHOP-14, 78.1% (73.2-83.0) for six cycles of R-CHOP-14, and 72.5% (67.1-77.9) for eight cycles of R-CHOP-14. Compared with treatment with six cycles of CHOP-14, overall survival improved by -1.7% (-10.0-6.6) after eight cycles of CHOP-14, 10.4% (2.8-18.0) after six cycles of R-CHOP-14, and 4.8% (-3.1-12.7) after eight cycles of R-CHOP-14. In a multivariate analysis that used six cycles of CHOP-14 without rituximab as the reference, and adjusting for known prognostic factors, all three intensified regimens improved 3-year event-free survival (eight cycles of CHOP-14: RR [relative risk] 0.76 [0.60-0.95], p=0.0172; six cycles of R-CHOP-14: RR 0.51 [0.40-0.65], p<0.0001; eight cycles of R-CHOP-14: RR 0.54 [0.43-0.69], p<0.0001). Progression-free survival improved after six cycles of R-CHOP-14 (RR 0.50 [0.38-0.67], p<0.0001), and eight cycles of R-CHOP-14 (RR 0.59 [0.45-0.77], p=0.0001). Overall survival improved only after six cycles of R-CHOP-14 (RR 0.63 [0.46-0.85], p=0.0031). In patients with a partial response after four cycles of chemotherapy, eight cycles were not better than six cycles. INTERPRETATION: Six cycles of R-CHOP-14 significantly improved event-free, progression-free, and overall survival over six cycles of CHOP-14 treatment. Response-adapted addition of chemotherapy beyond six cycles, though widely practiced, is not justified. Of the four regimens assessed in this study, six cycles of R-CHOP-14 is the preferred treatment for elderly patients, with which other approaches should be compared.

Essential role of stromally induced hedgehog signaling in B-cell malignancies.

Interaction of cancer cells with their microenvironment generated by stromal cells is essential for tumor cell survival and influences the localization of tumor growth. Here we demonstrate that hedgehog ligands secreted by bone-marrow, nodal and splenic stromal cells function as survival factors for malignant lymphoma and plasmacytoma cells derived from transgenic Emu-Myc mice or isolated from humans with these malignancies. Hedgehog pathway inhibition in lymphomas induced apoptosis through downregulation of Bcl2, but was independent of p53 or Bmi1 expression. Blockage of hedgehog signaling in vivo inhibited expansion of mouse lymphoma cells in a syngeneic mouse model and reduced tumor mass in mice with fully developed disease. Our data indicate that stromally induced hedgehog signaling may provide an important survival signal for B- and plasma-cell malignancies in vitro and in vivo. Disruption of this interaction by hedgehog pathway inhibition could provide a new strategy in lymphoma and multiple myeloma therapy.

Identification of their epitope reveals the structural basis for the mechanism of action of the immunosuppressive antibodies basiliximab and daclizumab.

Interleukin-2 (IL-2) and its receptor (IL-2R) play a major role in cellular immunity. The monoclonal antibodies basiliximab and daclizumab directed against the IL-2R subunit CD25 are widely used to prevent graft or host rejection after allogeneic tissue transplantation. Although these antibodies have been used for this purpose for many years, their common epitope within the CD25 protein is unknown. We screened a random phage display library to isolate peptides specifically binding to basiliximab. A striking amino acid sequence motif was enriched. This motif is homologous to the peptide ERIYHFV comprising amino acid positions 116 to 122 within the extracellular domain of CD25, suggesting that this is the basiliximab epitope. Basiliximab and daclizumab binding of selected phage was specific, as no binding was observed to isotype antibody controls. Phage binding could be inhibited by the cognate peptide. In cells expressing mutant CD25, binding of basiliximab was abolished when two or more amino acids of the suspected epitope were changed. In contrast, basiliximab binding remained unaffected in cells expressing CD25 versions with mutations outside this epitope. We therefore conclude that the (116)ERIYHFV(122) string within CD25 is the epitope recognized by basiliximab and daclizumab. This epitope overlaps with the interaction site of CD25 and IL-2, thus revealing the structural basis for the inhibition of IL-2R binding by this class of immunosuppressive antibodies.

Treatment decision-making for older patients with high-risk myelodysplastic syndrome or acute myeloid leukemia: problems and approaches.

BACKGROUND AND OBJECTIVES: High-risk myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML) are mainly diseases of patients over the age of 60 years. In these patients, intensive chemotherapy and/or allogeneic blood stem cell transplantation are the only curative treatment approaches, while non-curative options include low-dose chemotherapy or best supportive care alone. The basis for treatment decision-making in this clinically and biologically heterogeneous group is not well defined. DESIGN AND METHODS: In order to investigate treatment stratification patterns and outcomes in this population, we performed a systematic literature search in MedLine for relevant clinical reports published between 1989 and 2006. Only large population-based investigations and publications of clinical trials with more than 40 patients were analyzed. RESULTS: In 36 AML studies involving a total of 12,370 patients (median age 70 years) median overall survival approached 30 weeks for intensively treated patients. In patients receiving best supportive care alone, or best supportive care plus non-intensive treatment, median overall survival was 7.5 and 12 weeks, respectively. The complete remission rate after induction was 44%, and in those patients who achieved complete remission age no longer influenced prognosis. In 18 large studies approximately 50% of AML patients received induction therapy, 30% non-intensive chemotherapy and 20% supportive care only. INTERPRETATION AND CONCLUSIONS: Due to the scarcity of randomized AML/MDS trials in which older patients are assigned to either induction or less intense therapy, predictors to identify older patients most likely to benefit from intensive therapy and novel tools to optimize (or even standardize) recommendations are needed. We propose that in this patient population in the future, geriatric assessment instruments and comorbidity scoring are implemented in treatment decision-making.

The epitope recognized by rituximab.

Rituximab is a monoclonal antibody widely used in the treatment of malignant lymphoma and autoimmunity. Its epitope within the B-cell antigen CD20 is largely unknown. We used phage display libraries to select peptides binding to rituximab. Enriched peptides showed 2 sequence patterns: one motif (CALMIANSC) is related to (170)ANPS(173) within CD20, while another motif (WEWTI) may mimic the CD20 segment (182)YCYSI(185). Phages displaying either motif specifically bound rituximab. Binding to rituximab by the CD20 peptides ANPS and YCYSI was weak when used separately and enhanced when both peptides were linked. Recombinant CD20 extracellular loop proteins blocked binding of the selected CWWEWTIGC phage to rituximab, suggesting that CWWEWTIGC mimics the epitope. Blocking capacity was strongly reduced upon mutation of the CD20 strings ANPS or YCYSI. We conclude that rituximab binds a discontinuous epitope in CD20, comprised of (170)ANPS(173) and (182)YCYSI(185), with both strings brought in steric proximity by a disulfide bridge between C(167) and C(183).