Microfluidic device with integrated microfilter of conical-shaped holes for high efficiency and high purity capture of circulating tumor cells.

Capture of circulating tumor cells (CTCs) from peripheral blood of cancer patients has major implications for metastatic detection and therapy analyses. Here we demonstrated a microfluidic device for high efficiency and high purity capture of CTCs. The key novelty of this approach lies on the integration of a microfilter with conical-shaped holes and a micro-injector with cross-flow components for size dependent capture of tumor cells without significant retention of non-tumor cells. Under conditions of constant flow rate, tumor cells spiked into phosphate buffered saline could be recovered and then cultured for further analyses. When tumor cells were spiked in blood of healthy donors, they could also be recovered at high efficiency and high clearance efficiency of white blood cells. When the same device was used for clinical validation, CTCs could be detected in blood samples of cancer patients but not in that of healthy donors. Finally, the capture efficiency of tumor cells is cell-type dependent but the hole size of the filter should be more closely correlated to the nuclei size of the tumor cells. Together with the advantage of easy operation, low-cost and high potential of integration, this approach offers unprecedented opportunities for metastatic detection and cancer treatment monitoring.

Rapid separation of mononuclear hodgkin from multinuclear reed-sternberg cells.

We describe a method to isolate small mononucleated Hodgkin (H) cells from multinucleated Reed Sternberg (RS) cells of Hodgkin lymphoma using the ScreenCell filter device. This filtration-based approach lends itself to future clinical applications in that it enables the separation of H and RS cells from lymph node biopsies, bone marrow aspirates, pleural effusions, and blood, including the isolation of monoclonal Hodgkin precursor cells from the blood.

Three-Dimensional Telomeric Analysis of Isolated Circulating Tumor Cells (CTCs) Defines CTC Subpopulations.

Circulating tumor cells (CTCs) have been identified with the potential to serve as suitable biomarkers for tumor stage and progression, but the availability of effective isolation technique(s) coupled with detailed molecular characterization have been the challenges encountered in making CTCs clinically relevant. For the first time, we combined isolation of CTCs using the ScreenCell filtration technique with quantitative analysis of CTC telomeres by TeloView. This resulted in the identification and molecular characterization of different subpopulations of CTCs in the same patient. Three-dimensional (3D) telomeric analysis was carried out on isolated CTCs of 19 patients that consisted of four different tumor types, namely, prostate, colon, breast, melanoma, and one lung cancer cell line. With telomeric analysis of the filter-isolated CTCs, the level of chromosomal instability (CIN) of the CTCs can be determined. Our study shows that subpopulations of CTCs can be identified on the basis of their 3D telomeric properties.

A new device for rapid isolation by size and characterization of rare circulating tumor cells.

BACKGROUND: Circulating tumor cells (CTCs) likely derive from clones in the primary tumor, suggesting that they can be used for all biological tests applying to the primary cells. MATERIALS AND METHODS: The ScreenCell® devices are single-use and low-cost innovative devices that use a filter to isolate and sort tumor cells by size. RESULTS: The ScreenCell® Cyto device is able to isolate rare, fixed, tumor cells, with a high recovery rate. Cells are well preserved morphologically. Immunocytochemistry and FISH assays can be performed directly on the filter. The ScreenCell® CC device allows isolation of live cells able to grow in culture. High quality genetic materials can be obtained directly from tumor cells isolated on the ScreenCell® MB device filter. CONCLUSION: Due to their reduced size, versatility, and capacity to isolate CTCs within minutes, the ScreenCell® devices may be able to simplify and improve non-invasive access to tumor cells.

Dasatinib inhibits the growth of molecularly heterogeneous myeloid leukemias.

PURPOSE: Dasatinib is a dual Src/Abl inhibitor recently approved for Bcr-Abl+ leukemias with resistance or intolerance to prior therapy. Because Src kinases contribute to multiple blood cell functions by triggering a variety of signaling pathways, we hypothesized that their molecular targeting might lead to growth inhibition in acute myeloid leukemia (AML). EXPERIMENTAL DESIGN: We studied growth factor-dependent and growth factor-independent leukemic cell lines, including three cell lines expressing mutants of receptor tyrosine kinases (Flt3 or c-Kit) as well as primary AML blasts for responsiveness to dasatinib. RESULTS: Dasatinib resulted in the inhibition of Src family kinases in all cell lines and blast cells at approximately 1 x 10(-9) mol/L. It also inhibited mutant Flt3 or Kit tyrosine phosphorylation at approximately 1 x 10(-6) mol/L. Mo7e cells expressing the activating mutation (codon 816) of c-Kit were most sensitive to growth inhibition with a GI(50) of 5 x 10(-9) mol/L. Primary AML blast cells exhibited a growth inhibition of <1 x 10(-6) mol/L. Cell lines that showed growth inhibition at approximately 1 x 10(-6) mol/L showed a G(1) cell cycle arrest and correlated with accumulation of p21 and p27 protein. The addition of rapamycin or cytotoxic agents enhanced growth inhibition. Dasatinib also caused the apoptosis of Mo7e cells expressing oncogenic Kit. CONCLUSIONS: Although all of the precise targets for dasatinib are not known, this multikinase inhibitor causes either growth arrest or apoptosis in molecularly heterogeneous AML. The addition of cytotoxic or targeted agents can enhance its effects.

Contribution and limit of the model of perfused cotyledon to the study of placental transfer of drugs. Example of a protease inhibitor of HIV: nelfinavir.

OBJECTIVES: The perfused cotyledon model is a very useful method to study placental transfer of drugs. Here we studied placental transfer of the human immunodeficiency virus protease inhibitor nelfinavir using the non-recirculating dual human placental perfusion with a main goal to determining the clearance index of nelfinavir as related to maternal concentrations, and analyze the conditions under which ex vivo and in vivo data can be correlated. STUDY DESIGN: Thirteen human cotyledons, obtained after uneventful term pregnancies, were perfused in an open double circuit with nelfinavir (320-4436 microg/l) and a freely diffusing marker antipyrine 20 mg/l, in the presence of an albumin concentration of 2 g/l. Drug concentrations were determined by high-performance liquid chromatography. RESULTS: The mean clearance index of nelfinavir was very weak when maternal concentrations were under 500 microg/l (0.03+/-0.05). For maternal concentrations above 1200 microg/l, the mean fetal transfer rate was 14+/-3.4%, the mean clearance index was 0.39+/-0.10 and the fetal concentrations were between 133 and 671 microg/l. There was a good correlation between maternal and fetal concentrations (r=0.86; p<0.001). CONCLUSIONS: Our study with nelfinavir has achieved a good correlation between ex vivo and in vivo data. Our results also indicate that studies must be conducted under well defined conditions to obtain accurate and comparable data, underlining the fact that the ex vivo perfused cotyledon remains difficult to standardize as a model system.

PRAM-1 potentiates arsenic trioxide-induced JNK activation.

The promyelocytic leukemia RARalpha target gene encoding an adaptor molecule-1 (PRAM-1) is involved in a signaling pathway induced by retinoic acid in acute promyelocytic leukemia (APL) cells. To better understand the function of PRAM-1, we have undertaken the identification of its partners through a yeast two-hybrid screen. Here, we show that the proline-rich domain of PRAM-1 interacted with the Src homology 3 (SH3) domain of hematopoietic progenitor kinase 1 (HPK-1)-interacting protein of 55 kDa (HIP-55, also called SH3P7 and Abp1) known to stimulate the activity of HPK-1 and c-Jun N-terminal kinase (JNK). Overexpression of PRAM-1 in the NB4 APL cell line increased arsenic trioxide-induced JNK activation through a caspase 3-like-dependent activity. Dissociation of the SH3 domain from the rest of the HIP-55 protein was observed in the NB4 APL cell line treated with arsenic trioxide due to specific cleavage by caspase 3-like enzymes. The cleavage of HIP-55 correlated with the induction of PRAM-1 mRNA and protein expression. Taken together, our results suggest that the caspase 3-cleaved SH3 domain of HIP-55 is likely involved in PRAM-1-mediated JNK activation upon arsenic trioxide-induced differentiation of NB4 cells.

ASB2 is an Elongin BC-interacting protein that can assemble with Cullin 5 and Rbx1 to reconstitute an E3 ubiquitin ligase complex.

The ankyrin repeat-containing protein with a suppressor of cytokine signaling box-2 (ASB2) gene was identified as a retinoic acid-response gene and a target of the promyelocytic leukemia-retinoic acid receptor-alpha oncogenic protein characteristic of acute promyelocytic leukemia. Expression of ASB2 in myeloid leukemia cells inhibits growth and promotes commitment, recapitulating an early step known to be critical for differentiation. Here we show that ASB2, by interacting with the Elongin BC complex, can assemble with Cullin5.Rbx1 to form an E3 ubiquitin ligase complex that stimulates polyubiquitination by the E2 ubiquitin-conjugating enzyme Ubc5. This is a first indication that a member of the ASB protein family, ASB2, is a subunit of an ECS (Elongin C-Cullin-SOCS box)-type E3 ubiquitin ligase complex. Altogether, our results strongly suggest that ASB2 targets specific proteins to destruction by the proteasome in leukemia cells that have been induced to differentiate.

JAML, a novel protein with characteristics of a junctional adhesion molecule, is induced during differentiation of myeloid leukemia cells.

Retinoic acid induces clinical remission in acute promyelocytic leukemia (APL) by triggering differentiation of leukemia promyelocytes. Here, we have characterized a gene encoding a member of the immunoglobulin superfamily, among novel retinoic acid-induced genes identified in APL cells. This protein, which was named JAML (junctional adhesion molecule-like), contains 2 extracellular immunoglobulin-like domains, a transmembrane segment, and a cytoplasmic tail. JAML mRNA is expressed in hematopoietic tissues and is prominently expressed in granulocytes. The fact that JAML protein is localized at the cell plasma membrane in the areas of cell-cell contacts, whereas it is not detected at free cell borders, suggests that JAML is engaged in homophilic interactions. Furthermore, a conserved dimerization motif among JAM members was shown to be important for JAML localization at the cell membrane. Finally, exogenous expression of JAML in myeloid leukemia cells resulted in enhanced cell adhesion to endothelial cells. Altogether, our results point to JAML as a novel member of the JAM family expressed on leukocytes with a possible role in leukocyte transmigration.

ASB-2 inhibits growth and promotes commitment in myeloid leukemia cells.

In acute promyelocytic leukemia (APL) cells harboring the promyelocytic leukemia retinoic acid receptor alpha (PML-RARalpha) chimeric protein, retinoic acid (RA)-induced differentiation is triggered through a PML-RARalpha signaling resulting in activation of critical target genes. Induced differentiation of APL cells is always preceded by withdrawal from the cell cycle and commitment events leading to terminal differentiation. Here we have identified the human ankyrin repeat-containing protein with a suppressor of cytokine signaling box-2 (ASB-2) cDNA, as a novel RA-induced gene in APL cells. PML-RARalpha strongly enhanced RA-induced ASB-2 mRNA expression. In myeloid leukemia cells, ASB-2 expression induced growth inhibition and chromatin condensation recapitulating early events critical to RA-induced differentiation of APL cells.