[Show abstract][Hide abstract] ABSTRACT: Valproic acid (VPA), an histone deacetylase inhibitor (HDCAi), is emerging as a promising therapeutic agent for the treatments of gliomas by virtue of its ability to reactivate the expression of epigenetically silenced genes. VPA induces the unfolded protein response (UPR), an adaptive pathway displaying a dichotomic yin yang characteristic: it initially contributes in safeguarding the malignant cell survival while long lasting activation favors proapoptotic response. By triggering UPR, VPA might tip the balance between cellular adaptation and programmed cell death via the deregulation of protein homeostasis and induction of proteotoxicity. Here we aimed to investigate the impact of proteostasis on glioma stem cells (GSC) using VPA treatment combined with subversion of SEL1L, a crucial protein involved in homeostatic pathways, cancer aggressiveness and stem cell state maintenance. We investigated the global expression of GSC lines untreated and treated with VPA, SEL1L interference and GSC line response to VPA treatment by analyzing cell viability via MTT assay, neurosphere formation and ER stress/UPR responsive proteins. Moreover, SEL1L immunohistochemistry was performed on primary glial tumors. The results show that i. VPA affects GSC lines viability and anchorage dependent growth by inducing differentiative programs and cell cycle progression ii. SEL1L downmodulation synergically enhances VPA cytotoxic effects by influencing GSCs proliferation and self-renewal properties, iii. SEL1L expression is indicative of glioma rate of proliferation, malignancy a endoplasmic reticulum (ER) stress statuses. Targeting the proteostasis network in association to VPA treatment may provide an alternative approach to deplete GSC and improve glioma treatments.
[Show abstract][Hide abstract] ABSTRACT: Tissue microarray (TMA) and cell microarray (CMA) are two powerful techniques that allow for the immunophenotypical characterization of hundreds of samples simultaneously. In particular, the CMA approach is particularly useful for immunophenotyping new stem cell lines (e.g., cardiac, neural, mesenchymal) using conventional markers, as well as for testing the specificity and the efficacy of newly developed antibodies. We propose the use of a tissue arrayer not only to perform protein expression profiling by immunohistochemistry but also to carry out molecular genetics studies. In fact, starting with several tissues or cell lines, it is possible to obtain the complete signature of each sample, describing the protein, mRNA and microRNA expression, and DNA mutations, or eventually to analyze the epigenetic processes that control protein regulation. Here we show the results obtained using the Galileo CK4500 TMA platform.
Journal of Histochemistry and Cytochemistry 11/2012; DOI:10.1369/0022155412470455 · 2.40 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The use of human stem cells in biomedical research projects is increasing steadily and the number of cells that are being derived develops at a remarkable pace. However, stem cells around the world are vastly different in their provenance, programming, and potentials. Furthermore, knowledge on the actual number of cell types, their derivation, availability, and characteristics is rather sparse. Usually, "colleague-supply" avenues constantly furnish cells to laboratories around the world without ensuring their correct identity, characterization, and quality. These parameters are critical if the cells will be eventually used in toxicology studies and drug discovery. Here, we outline some basic principles in establishing a stem cell-specific bank.
[Show abstract][Hide abstract] ABSTRACT: The potential use of neural stem cells (NSCs) in basic research, drug testing, and for the development of therapeutic strategies is dependent on their large scale in vitro amplification which, however, introduces considerable risks of genetic instability and transformation. NSCs have been derived from different sources, but the occurrence of chromosomal instability has been monitored only to a limited extent in relationship to the source of derivation, growth procedure, long-term culture, and genetic manipulation. Here we have systematically investigated the effect of these parameters on the chromosomal stability of pure populations of mouse NSCs obtained after neuralization from embryonic stem cells (ESCs) or directly from fetal or adult mouse brain. We found that the procedure of NSCs establishment is not accompanied by genetic instability and chromosomal aberration. On the contrary, we observed that a composite karyotype appears in NSCs above extensive passaging. This phenomenon is more evident in ESC- and adult sub-ventricular zone-derived NSCs and further deteriorates after genetic engineering of the cells. Fetal-derived NSCs showed the greatest euploidy state with negligible clonal structural aberrations, but persistent clonal numerical abnormalities. It was previously published that long-term passaged ESC- and adult sub-ventricular zone-derived NSCs did not show any defects in the cells' proliferative and differentiative capacity nor induced in vivo tumour formation, although we here report on the chromosomal abnormalities of these cells. Although chromosomal aberrations are known to occur less frequently in human cells, studies performed on murine stem cells provide an important complement to understand the biological events occurring in human lines.
Stem cells and development 08/2011; 20(8):1411-23. DOI:10.1089/scd.2010.0359 · 4.20 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The validity of results from biomarker studies using archived specimens depends on the integrity of the specimens and the manner in which they are collected, processed, and stored. The management of a huge amount of biomaterial generated from research studies and clinical trials is becoming a very demanding task and many organizations are facing the choice between in-house storage and processing and outsourcing some activities. Storage and logistic functions are the prime targets for outsourcing, because to sustain these critical assets organizations must have the expertise, the dedicated qualified personnel, the proper quality control programs, and available resources to fulfill the mandatory requirements to maintain the integrity of the samples. External biobanks are dedicated and certified infrastructures (ISO, GMP, etc.) that apply efficient logistic and shipping activities, use validated standard operating procedures, install appropriate monitoring back-up systems, and, most of all, have room for expansion. Thus, the choice between in-house biobanking and outsourcing cannot be exclusively based on a financial decision; it must also consider (i) type of collection/project, (ii) logistic complexity (number and locations of collection sites), (iii) safety requirements, (iv) functional expertise, and (v) business priorities.
Biopreservation and Biobanking 06/2011; 9(2):191-4. DOI:10.1089/bio.2011.0002 · 1.58 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Murine SEL-1L (mSEL-1L) is a key component of the endoplasmic reticulum-associated degradation pathway. It is essential during development as revealed by the multi-organ dysfunction and in uterus lethality occurring in homozygous mSEL-1L-deficient mice. Here we show that mSEL-1L is highly expressed in pluripotent embryonic stem cells and multipotent neural stem cells (NSCs) but silenced in all mature neural derivatives (i.e. astrocytes, oligodendrocytes, and neurons) by mmu-miR-183. NSCs derived from homozygous mSEL-1L-deficient embryos (mSEL-1L(-/-) NSCs) fail to proliferate in vitro, show a drastic reduction of the Notch effector HES-5, and reveal a significant down-modulation of the early neural progenitor markers PAX-6 and OLIG-2, when compared with the wild type (mSEL-1L(+/+) NSCs) counterpart. Furthermore, these cells are almost completely deprived of the neural marker Nestin, display a significant decrease of SOX-2 expression, and rapidly undergo premature astrocytic commitment and apoptosis. The data suggest severe self-renewal defects occurring in these cells probably mediated by misregulation of the Notch signaling. The results reported here denote mSEL-1L as a primitive marker with a possible involvement in the regulation of neural progenitor stemness maintenance and lineage determination.
[Show abstract][Hide abstract] ABSTRACT: Quality-assessed biomedical samples are essential for academia- and industry driven research on human diseases. The etiologies and the molecular genetic factors relevant in African diseases, including both infections and complex degenerative diseases as well as cancer, need to be studied using well annotated and well-preserved biosamples acquired from native African ethnic groups and compare the results with non-African populations and/or with Afro-Americans. However, a number of difficulties negatively impact on the possibility to obtain clinically annotated biological samples in most Sub-Saharan African countries. This is mainly due to major organizational problems, lack of clinical centres that can dedicate resources to research, as well as lack of facilities in which biomaterials can be properly processed and safely stored. Harmonization of biosample acquisition, storage phenotyping schemes and biocomputer infrastructures are the principal objectives of biological resource centers (BRCs). BRCs comprise biobanks of different formats (collection of blood, DNA, tissues, etc., annotated with medical, environmental, life-style and follow up data) a fundamental tool for molecular epidemiological studies aiming to increase excellence and efficacy of biomedical results, drug development and public health. BRCs provide large and highly controlled biomolecular resources necessary to meet the "omics" scientific platforms. Sudan may be a candidate nation to host such infrastructure, in view of its strategic geographical position and the already existing simple biobanking experiences connected with research groups in Central Sudan. Here, we describe the potential role of biobanks in African genetic studies aiming to dissect the eziopathogenesis of complex diseases in relation to environmental and life-style factors.
Science of The Total Environment 02/2011; 423:210-3. DOI:10.1016/j.scitotenv.2010.07.054 · 4.10 Impact Factor