CD133 Expression Is Not Synonymous to Immunoreactivity for AC133 and Fluctuates throughout the Cell Cycle in Glioma Stem-Like Cells

A transmembrane protein CD133 has been implicated as a marker of stem-like glioma cells and predictor for therapeutic response in malignant brain tumours. CD133 expression is commonly evaluated by using antibodies specific for the AC133 epitope located in one of the extracellular domains of membrane-bound CD133. There is conflicting evidence regarding the significance of the AC133 epitope as a marker for identifying stem-like glioma cells and predicting the degree of malignancy in glioma cells. The reasons for discrepant results between different studies addressing the role of CD133/AC133 in gliomas are unclear. A possible source for controversies about CD133/AC133 is the widespread assumption that expression patterns of the AC133 epitope reflect linearly those of the CD133 protein. Consequently, the readouts from AC133 assessments are often interpreted in terms of the CD133 protein. The purpose of this study is to determine whether and to what extent do the readouts obtained with anti-AC133 antibody correspond to the level of CD133 protein expressed in stem-like glioma cells. Our study reveals for the first time that CD133 expressed on the surface of glioma cells is poorly immunoreactive for AC133. Furthermore, we provide evidence that the level of CD133 occupancy on the surface of glioma cells fluctuates during the cell cycle. Our results offer a new explanation for numerous inconsistencies regarding the biological and clinical significance of CD133/AC133 in human gliomas and call for caution in interpreting the lack or presence of AC133 epitope in glioma cells.     

Biosimilars 2.0: Guiding principles for a global “patients first” standard

In the European Union, biosimilar products have been approved since 2006 under an abbreviated pathway that leverages their similarity to an existing “reference” biological product. The products approved to date are based on recombinant versions of endogenous proteins with well-understood structures and pharmacology, but complicated safety and immunogenicity profiles. The period during the 2000s that included the first reviews, approvals, sale and use of biosimilars is referred to herein as “Biosimilars 1.0.” Over the next several years, a new and advanced tranche of biosimilars will be developed for complex reference products, including medicines used in the treatment of cancer and autoimmune diseases. A global market for biosimilars is developing and this may well foreshadow the beginning of the second era of product development. This Biosimilars 2.0 period will likely be characterized by the development of complex products, global harmonization of standards and the increasing demand for long-term monitoring of pharmaceuticals. The products developed in this period should exhibit high levels of fidelity to the reference products and should be rigorously evaluated in analytical, non-clinical and clinical comparisons. Additionally, Biosimilars 2.0 manufacturers should strive for transparency in their labels and take proactive strides to be accountable to providers and patients for the quality of their products. An important opportunity now exists for the healthcare community, industry and regulators to work in partnership, to outline the appropriate standards for these products and to facilitate increased access while meeting patients'' needs.Key words: biotechnology, biosimilars, generic drugs, monoclonal antibodies, pharmacodynamics, pharmacokinetics     

Lysosomal storage disorder in non-immunological hydrops fetalis (NIHF) - more common than assumed? Report of four cases with transient NIHF and a review of the literature

Background

Lysosomal storage disorders (LSD) are a rare cause of non immunological hydrops fetalis (NIHF) and congenital ascites. The reported incidence is about 1%. The incidence of idiopathic NIHF is estimated to be about 18%.

Patients and methods

We report four cases with transient hydrops fetalis resulting from LSD and performed a literature review on LSD with NIHF and congenital ascites in combination.

Results

At present, 12 different LSDs are described to be associated with NIHF or congenital ascites. Most patients had a family history of NIHF, where the preceding sibling had not been examined. A diagnostic approach to the fetus with NIHF due to suspected LSD either in utero or postnatal is suggested. Transient forms of NIHF and/or ascites in association with MPS IVA, MPS VII and NPC are described for the first time in this publication.

Conclusions

LSD should be considered in transient hydrops. Enzymatic studies in chorionic villous sample or amniotic cultured cells, once the most common conditions associated with fetal ascites or hydrops have been ruled out, are important. This paper emphasizes the fact that LSD is significantly higher than the estimated 1% in previous studies, which is important for genetic counseling as there is a high risk of recurrence and the availability of enzyme replacement therapy for an increasing number of LSD.

     

Spondylocheiro dysplastic form of the Ehlers-Danlos syndrome--an autosomal-recessive entity caused by mutations in the zinc transporter gene SLC39A13

We present clinical, radiological, biochemical, and genetic findings on six patients from two consanguineous families that show EDS-like features and radiological findings of a mild skeletal dysplasia. The EDS-like findings comprise hyperelastic, thin, and bruisable skin, hypermobility of the small joints with a tendency to contractures, protuberant eyes with bluish sclerae, hands with finely wrinkled palms, atrophy of the thenar muscles, and tapering fingers. The skeletal dysplasia comprises platyspondyly with moderate short stature, osteopenia, and widened metaphyses. Patients have an increased ratio of total urinary pyridinolines, lysyl pyridinoline/hydroxylysyl pyridinoline (LP/HP), of approximately 1 as opposed to approximately 6 in EDS VI or approximately 0.2 in controls. Lysyl and prolyl residues of collagens were underhydroxylated despite normal lysyl hydroxylase and prolyl 4-hydroxylase activities; underhydroxylation was a generalized process as shown by mass spectrometry of the alpha1(I)- and alpha2(I)-chain-derived peptides of collagen type I and involved at least collagen types I and II. A genome-wide SNP scan and sequence analyses identified in all patients a homozygous c.483_491 del9 SLC39A13 mutation that encodes for a membrane-bound zinc transporter SLC39A13. We hypothesize that an increased Zn(2+) content inside the endoplasmic reticulum competes with Fe(2+), a cofactor that is necessary for hydroxylation of lysyl and prolyl residues, and thus explains the biochemical findings. These data suggest an entity that we have designated "spondylocheiro dysplastic form of EDS (SCD-EDS)" to indicate a generalized skeletal dysplasia involving mainly the spine (spondylo) and striking clinical abnormalities of the hands (cheiro) in addition to the EDS-like features.     

Biofilm and Diatom Succession on Polyethylene (PE) and Biodegradable Plastic Bags in Two Marine Habitats: Early Signs of Degradation in the Pelagic and Benthic Zone?

The production of biodegradable plastic is increasing. Given the augmented littering of these products an increasing input into the sea is expected. Previous laboratory experiments have shown that degradation of plastic starts within days to weeks. Little is known about the early composition and activity of biofilms found on biodegradable and conventional plastic debris and its correlation to degradation in the marine environment. In this study we investigated the early formation of biofilms on plastic shopper bags and its consequences for the degradation of plastic. Samples of polyethylene and biodegradable plastic were tested in the Mediterranean Sea for 15 and 33 days. The samples were distributed equally to a shallow benthic (sedimentary seafloor at 6 m water depth) and a pelagic habitat (3 m water depth) to compare the impact of these different environments on fouling and degradation. The amount of biofilm increased on both plastic types and in both habitats. The diatom abundance and diversity differed significantly between the habitats and the plastic types. Diatoms were more abundant on samples from the pelagic zone. We anticipate that specific surface properties of the polymer types induced different biofilm communities on both plastic types. Additionally, different environmental conditions between the benthic and pelagic experimental site such as light intensity and shear forces may have influenced unequal colonisation between these habitats. The oxygen production rate was negative for all samples, indicating that the initial biofilm on marine plastic litter consumes oxygen, regardless of the plastic type or if exposed in the pelagic or the benthic zone. Mechanical tests did not reveal degradation within one month of exposure. However, scanning electron microscopy (SEM) analysis displayed potential signs of degradation on the plastic surface, which differed between both plastic types. This study indicates that the early biofilm formation and composition are affected by the plastic type and habitat. Further, it reveals that already within two weeks biodegradable plastic shows signs of degradation in the benthic and pelagic habitat.     

Pseudodeficiency of arylsulfatase A: a common genetic polymorphism with possible disease implications

Summary The distribution and frequency of aphidicolin-induced common fragile sites were studied in chromosomes of cultured skin fibroblasts and PHA-stimulated lymphocytes from five normal individuals; 0.2 M aphidicolin was added for the last 26 h of culture. Skin fibroblasts from five fra(X)-positive patients were also studied in the same manner. Fragile sites most frequently found in fibroblasts from normal individuals were 3q26.2, 7q11.23, 16q23, 1p31, 10q11.2, 12q23 and 7q31, whereas those in lymphocytes from the same individuals were 3p14, 16q23, Xp22, 7q32 and 14q24. The distribution of fragile sites in fibroblasts from fra(X)-positive patients was essentially identical with that in normal individuals. The average number of gaps and breaks in 100 metaphases was 36.8 in fibroblasts from normal individuals, 113.8 in those from fra(X)-positive patients, and 279 in lymphocytes from normal individuals. Their rates of chromosome-type breaks and gaps were 7.9%, 29.7% and 54.5%, respectively. Thus, the distribution and frequency of aphidicolin-induced fragile sites were different between skin fibroblasts and lymphocytes, possibly reflecting differences in their DNA replication sequence or gene activity.     

Evaluation of Different Biomarkers to Predict Individual Radiosensitivity in an Inter-Laboratory Comparison–Lessons for Future Studies

Radiotherapy is a powerful cure for several types of solid tumours, but its application is often limited because of severe side effects in individual patients. With the aim to find biomarkers capable of predicting normal tissue side reactions we analysed the radiation responses of cells from individual head and neck tumour and breast cancer patients of different clinical radiosensitivity in a multicentric study. Multiple parameters of cellular radiosensitivity were analysed in coded samples of peripheral blood lymphocytes (PBLs) and derived lymphoblastoid cell lines (LCLs) from 15 clinical radio-hypersensitive tumour patients and compared to age- and sex-matched non-radiosensitive patient controls and 15 lymphoblastoid cell lines from age- and sex- matched healthy controls of the KORA study. Experimental parameters included ionizing radiation (IR)-induced cell death (AnnexinV), induction and repair of DNA strand breaks (Comet assay), induction of yH2AX foci (as a result of DNA double strand breaks), and whole genome expression analyses. Considerable inter-individual differences in IR-induced DNA strand breaks and their repair and/or cell death could be detected in primary and immortalised cells with the applied assays. The group of clinically radiosensitive patients was not unequivocally distinguishable from normal responding patients nor were individual overreacting patients in the test system unambiguously identified by two different laboratories. Thus, the in vitro test systems investigated here seem not to be appropriate for a general prediction of clinical reactions during or after radiotherapy due to the experimental variability compared to the small effect of radiation sensitivity. Genome-wide expression analysis however revealed a set of 67 marker genes which were differentially induced 6 h after in vitro-irradiation in lymphocytes from radio-hypersensitive and non-radiosensitive patients. These results warrant future validation in larger cohorts in order to determine parameters potentially predictive for clinical radiosensitivity.