Uptake of functionalized, fluorescent-labeled polymeric particles in different cell lines and stem cells

Labeling of cells with particles for in-vivo detection is interesting for various biomedical applications. The objective of this study was to evaluate the feasibility and efficiency labeling of cells with polymeric particles without the use of transfection agents. We hypothesized that surface charge would influence cellular uptake. The submicron particles were synthesized by the miniemulsion process. A fluorescent dye which served as reporter was embedded in these particles. The surface charge was varied by adjusting the amount of copolymerized monomer with amino group thus enabling to study the cellular uptake in correlation to the surface charge. Fluorescent-activated cell sorter (FACS) measurements were performed for detecting the uptake of the particles or attachment of particles in mesenchymal stem cells (MSC), and the three cell lines HeLa, Jurkat, and KG1a. These cell lines were chosen as they can serve as models for clinically interesting cellular targets. For these cell lines-with the exception of MSCs-a clear correlation of surface charge and fluorescence intensity could be shown. For an efficient uptake of the submicron particles, no transfection agents were needed. Confocal laser scanning microscopy and transmission electron microscopy (TEM) revealed differences in subcellular localization of the particles. In MSCs and HeLa particles were mostly located inside of cellular compartments resembling endosomes, while in Jurkat and KG1a, nanoparticles were predominantly located in clusters on the cell surface. Scanning electron microscopy showed microvilli to be involved in this process.

Miniemulsion Droplets as Single Molecule Nanoreactors for Polymerase Chain Reaction

Polymerase chain reaction (PCR) was successfully carried out inside stable and narrowly distributed water-in-oil nanodroplets with a size of 100-300 nm in diameter. The droplets were obtained by the miniemulsion process. Each aqueous droplet serves as a single nanoreactor for the PCR. It was found that the size of the droplets highly depends on the sonication parameters (i.e., time and amplitude) and that these parameters have a great influence on the final concentration of the PCR product. The parameters were chosen that way that conditions for single molecule chemistry were obtained, since the 3D-space is compartimentalized in small nanoreactors in each of which the same reaction takes place in a highly parallel fashion on every single DNA molecule.

Severe Pulmonary Toxicity in Patients With Advanced-Stage Hodgkin's Disease Treated With a Modified Bleomycin, Doxorubicin, Cyclophosphamide, Vincristine, Procarbazine, Prednisone, and Gemcitabine (BEACOPP) Regimen Is Probably Related to the Combination of Gemcitabine and Bleomycin: A Report of the German Hodgkin's Lymphoma Study Group

Purpose

To investigate a new effective, nonleukemogenic polychemotherapy regimen, BAGCOPP (bleomycin, doxorubicin, cyclophosphamide, vincristine, procarbazine, prednisone, gemcitabine) in a phase I/II dose-escalation study in patients with advanced-stage Hodgkin's disease (HD).

Patients and Methods

Patients in clinical stages IIB with risk factors III and IV were enrolled in this nonrandomized, multicenter trial aimed at defining the maximum-tolerated dose of gemcitabine within a modified escalated BEACOPP regimen. Gemcitabine was given at a starting dose of 800 mg/m2 on days 1 and 4 of each cycle.

Results

Twenty-seven patients (eight female, 19 male) were enrolled with a median age of 33 years (range, 19 to 65 years). Due to a higher than expected hematotoxicity, the day-4 application of gemcitabine was omitted after 14 patients were included and 59 cycles were given. A total of eight patients developed lung toxicity, mainly pneumonitis (six of eight), which led to the termination of the study. With a median follow-up of 27 months, 25 patients are in continuing complete remission.

Conclusion

The substitution of etoposide by gemcitabine in the escalated BEACOPP schema is not feasible and leads to severe pulmonary toxicity. This toxicity is probably related to the concomittant application of gemcitabine and bleomycin.

Possible regulation of Wilms' tumour gene 1 (WT1) expression by the paired box genes PAX2 and PAX8 and by the haematopoietic transcription factor GATA-1 in human acute myeloid leukaemias

Overexpression of the embryonic transcription factor, Wilms' tumour protein 1 (WT1), is common in acute myeloid leukaemias (AML). Mutations of Wilms' tumour gene 1 (WT1) in AML are rare and WT1 expression may be increased by other transcription factors. PAX2, PAX8 and GATA-1 are known physiological regulators of WT1. In the present study, we analysed either bone marrow or blood samples of 43 AML patients for the expression levels of WT1, PAX2, PAX8 and GATA-1 by real-time reverse transcription polymerase chain reaction (LightCycler). Bone marrow samples of patients without haematological malignancies and stem cell preparation samples from healthy donors and lymphoma patients served as controls. PAX2 expression was found in 11 of 43 AML samples, with a clear correlation of PAX2 with WT1 expression levels observed. PAX8 expression was found in two additional samples. GATA-1 expression was detectable in 41 of 43 AML samples and also in all control samples; no significant differences between these groups were observed and no correlation of GATA-1 expression with WT1 expression levels was apparent. In conclusion, PAX2, and possibly PAX8, appears to be a candidate for the upregulation of WT1 in a proportion of AML, whereas GATA-1 expression cannot be explained as an inducer of WT1. In two-thirds of leukaemias from our series, the basis of WT1 upregulation cannot be explained by the simple upregulation of the known WT1 activators.

Bone marrow contains melanoma-reactive CD8+ effector T cells and, compared with peripheral blood, enriched numbers of melanoma-reactive CD8+ memory T cells

Circulating melanoma-specific T cells can be frequently detected in patients with melanoma. Effective T-cell immunity and tumor surveillance, however, requires the presence of specific T cells in tissues populated by tumor cells. The bone marrow (BM) is a compartment frequently harboring micrometastatic tumor cells. Here, we compared directly ex vivo in peripheral blood (PB) and BM frequencies and differentiation phenotypes of T cells reactive with the melanoma-associated antigen tyrosinase and with autologous melanoma cells. Using intracellular cytokine and tetramer staining, we detected tyrosinase- and melanoma-reactive CD3+CD8+ T cells in the BM in similar or enhanced frequencies as in PB. Additional characterization of the differentiation subset using CD45RA and CCR7 revealed the presence of specific effector and memory T cells in the BM in all five patients analyzed. Remarkably, the frequency of tyrosinase- and melanoma-specific memory T cells was significantly increased in BM compared with PB. Thus, the BM may be an important compartment for tumor surveillance harboring a tumor-specific memory T-cell pool in addition to effector T cells.

Resistance of ex vivo expanded CD3+CD56+ T cells to Fas-mediated apoptosis

A variety of malignancies express Fas ligand (FasL), which can induce apoptosis in effector lymphocytes and may limit the success of cellular immunotherapy. Our laboratory has been investigating a population of ex vivo activated T cells, termed cytokine-induced killer (CIK) cells. These cells share functional and phenotypic properties with natural killer cells and a subset of cytolytic cells have the phenotype CD3+CD56+. CIK cells expand in culture, have significant antitumor activity and are presently being tested in phase I/II clinical trials. In this study, we investigated the sensitivity of CIK cells to Fas-mediated apoptosis. Fas engagement leads to apoptosis in small numbers of CIK cells and does not significantly influence antitumor cytotoxicity. CIK cells will undergo apoptosis following Fas engagement when protein synthesis is inhibited, suggesting the expression of antiapoptotic genes. Evaluation of antiapoptotic gene transcripts shows an upregulation in the expression of cFLIP, Bcl-2, Bcl-xL, DAD1 and survivin. Resistance to Fas-mediated apoptosis may come about through an in vitro selection for Fas resistance, since CIK cells synthesize FasL and supernatant from CIK cultures contains biologically active soluble FasL, which can be inhibited with Fas:Fc. These results indicate that CIK cells are a suitable form of immunotherapy against FasL-positive tumors.

Visualizing the kinetics of tumor-cell clearance in living animals

Evaluation of potential antineoplastic therapies would be enhanced by noninvasive detection of tumor cells in living animals. Because light is transmitted through mammalian tissues, it was possible to use bioluminescence to monitor (both externally and quantitatively) growth and regression of labeled human cervical carcinoma (HeLa) cells engrafted into immunodeficient mice. The efficacy of both chemotherapy and immunotherapeutic treatment with ex vivo expanded human T cell-derived effector cells was evaluated. In the absence of therapy, animals showed progressive increases in signal intensity over time. Animals treated with cisplatin had marked reductions in tumor signal; 5'-fluorouracil was less effective, and cyclophosphamide was ineffective. Immunotherapy dramatically reduced signals at high effector-to-target cell ratios, and significant decreases were observed with lower ratios. This model system allowed sensitive, quantitative, real-time spatiotemporal analyses of the dynamics of neoplastic cell growth and facilitated rapid optimization of effective treatment regimens.

Novel muscle chloride channel mutations and their effects on heterozygous carriers

Mutations within CLCN1, the gene encoding the major skeletal muscle chloride channel, cause either dominant Thomsen disease or recessive Becker-type myotonia, which are sometimes difficult to discriminate, because of reduced penetrance or lower clinical expressivity in females. We screened DNA of six unrelated Becker patients and found four novel CLCN1 mutations (Gln-74-Stop, Tyr-150-Cys, Tyr-261-Cys, and Ala-415-Val) and a previously reported 14-bp deletion. Five patients were homozygous for the changes (Gln-74-Stop, Ala-415-Val, and 14-bp deletion), four of them due to parental consanguinity. The sixth patient revealed compound heterozygosity for Tyr-150-Cys and Tyr-261-Cys. Heterozygous carriers of the Becker mutations did not display any clinical symptoms of myotonia. However, all heterozygous males, but none of the heterozygous females, exhibited myotonic discharges in the electromyogram suggesting (i) a gene dosage effect of the mutations on the chloride conductance and (ii) male predominance of subclinical myotonia. Furthermore, we report a novel Gly-200-Arg mutation resulting in a dominant phenotype in a male and a partially dominant phenotype in his mother. We discuss potential causes of the gender preference and the molecular mechanisms that may determine the mode of inheritance.

Myotonia levior is a chloride channel disorder

The group of dominant non-dystrophic myotonias, comprising disorders characterized by clinically similar forms of myogenic muscle stiffness, is genetically inhomogeneous. Dominant myotonia congenita (Thomsen's disease) is linked to CLCN1, the gene encoding the major muscle chloride channel, localized on chromosome 7q35. In contrast, dominant myotonias sensitive to potassium are caused by point mutations in SCN4A on chromosome 17q, the gene for the alpha subunit of the adult skeletal muscle sodium channel. No linkage or molecular genetic data are as yet available on 'myotonia levior' characterized by milder symptoms and later onset of myotonia than in Thomsen's disease, and absence of muscle hypertrophy. We report a CLCN1 Gln-552-Arg substitution for a family with dominant inheritance previously diagnosed to have myotonia levior. Thus, this disorder appears as a variant of Thomsen's disease due to mutations leading to low clinical expressivity. In addition, we report a novel Ile-290-Met CLCN1 mutation for a typical Thomsen pedigree. In another family previously diagnosed as having Thomsen's disease, we unexpectedly found a CLCN1 14 bp deletion known to cause recessive myotonia, and a rare Trp-118-Gly polymorphism.

Effect of heavy metals on cellular growth, metabolism and integrity of cultured Chinese hamster kidney cells

The effects of CdCl2, Na2CrO4, NaAsO2 and NiSO4 on cultured Chinese hamster kidney cells were studied over a concentration range for 48 h. Release of lactate dehydrogenase, a parameter of cell viability, was not closely related to cell proliferation except for Na2CrO4. A better correlation was obtained between glucose consumption and lactate production, and cellular growth. When studying toxic effects of metals in cell-culture systems, metabolic parameters should be determined in addition to cell viability and cellular growth. The results indicate that Chinese hamster kidney cells in culture might be useful to study mechanisms of metal-induced toxicity.