Heterogeneities in Cell Cycle Checkpoint Activation Following Doxorubicin Treatment Reveal Targetable Vulnerabilities in Mutated Ultra High-Risk Neuroblastoma Cell Lines.

Most chemotherapeutics target DNA integrity and thereby trigger tumour cell death through activation of DNA damage responses that are tightly coupled to the cell cycle. Disturbances in cell cycle regulation can therefore lead to treatment resistance. Here, a comprehensive analysis of cell cycle checkpoint activation following doxorubicin (doxo) treatment was performed using flow cytometry, immunofluorescence and live-cell imaging in a panel of mutated ultra high-risk neuroblastoma (NB) cell lines, SK-N-DZ, Kelly, SK-N-AS, SK-N-FI, and BE(2)-C.

Doxorubicin-provoked increase of mitotic activity and concomitant drain of G0-pool in therapy-resistant BE(2)-C neuroblastoma.

In this study chemotherapy response in neuroblastoma (NB) was assessed for the first time in a transplantation model comprising non-malignant human embryonic microenvironment of pluripotent stem cell teratoma (PSCT) derived from diploid bona fide hESC. Two NB cell lines with known high-risk phenotypes; the multi-resistant BE(2)-C and the drug sensitive IMR-32, were transplanted to the PSCT model and the tumour growth was exposed to single or repeated treatments with doxorubicin, and thereafter evaluated for cell death, apoptosis, and proliferation. Dose dependent cytotoxic effects were observed, this way corroborating the experimental platform for this type of analysis.

Loss of miR-514a-3p regulation of PEG3 activates the NF-kappa B pathway in human testicular germ cell tumors.

Deregulation of microRNAs (miRNAs) contributes to the development and progression of many cancer types; however, their functions in the pathogenesis of testicular germ cell tumor (TGCT) remain unclear. Here, we determined miRNA expression profiles of TGCTs and normal testes using small RNA sequencing, and identified several deregulated miRNAs in TGCTs, including the miR-506~514 cluster. In functional studies in vitro we demonstrated that miR-514a-3p induced apoptosis through direct regulation of the paternally expressed gene 3 (PEG3), and ectopically expressed PEG3 could rescue the apoptotic effect of miR-514a-3p overexpression.

Induction of sensory neurons from neuroepithelial stem cells by the ISX9 small molecule.

Hearing impairment most often involves loss of sensory hair cells and auditory neurons. As this loss is permanent in humans, a cell therapy approach has been suggested to replace damaged cells. It is thus of interest to generate lineage restricted progenitor cells appropriate for cell based therapies.

Non-CG DNA methylation is a biomarker for assessing endodermal differentiation capacity in pluripotent stem cells.

Non-CG methylation is an unexplored epigenetic hallmark of pluripotent stem cells. Here we report that a reduction in non-CG methylation is associated with impaired differentiation capacity into endodermal lineages. Genome-wide analysis of 2,670 non-CG sites in a discovery cohort of 25 phenotyped human induced pluripotent stem cell (hiPSC) lines revealed unidirectional loss (Δβ=13%, P<7.

Stem Cell Therapy in Injured Vocal Folds: A Three-Month Xenograft Analysis of Human Embryonic Stem Cells.

We have previously shown that human embryonic stem cell (hESC) therapy to injured rabbit vocal folds (VFs) induces human tissue generation with regained VF vibratory capacity. The aims of this study were to test the sustainability of such effect and to what extent derivatives of the transplanted hESCs are propagated in the VFs. The VFs of 14 New Zealand rabbits were injured by a localized resection.

Experimental teratoma: at the crossroad of fetal- and onco-development.

Xenografting is the so far only available in vivo model for assessing pluripotency of human stem cells. This review describes known biological features of experimental teratoma from human pluripotent stem cells. We focus on the dual nature mimicking both normal and abnormal development, and propose this model system to be particularly interesting for investigations of the relationship between developmentally controlled differentiation and neoplasia of embryonic origin.

Glial origin of mesenchymal stem cells in a tooth model system.

Mesenchymal stem cells occupy niches in stromal tissues where they provide sources of cells for specialized mesenchymal derivatives during growth and repair. The origins of mesenchymal stem cells have been the subject of considerable discussion, and current consensus holds that perivascular cells form mesenchymal stem cells in most tissues. The continuously growing mouse incisor tooth offers an excellent model to address the origin of mesenchymal stem cells.

Tropism of the in situ growth from biopsies of childhood neuroectodermal tumors following transplantation into experimental teratoma.

Experimental teratoma induced from human pluripotent stem cells with normal karyotype can be described as a failed embryonic process and includes besides advanced organoid development also large elements of tissue with a prolonged occurrence of immature neural components. Such immature components, although benign, exhibit strong morphological resemblance with tumors of embryonic neuroectodermal origin. Here, we demonstrate that biopsy material from childhood tumors of neural embryonic origin transplanted to mature experimental teratoma can show an exclusive preference for matching tissue.

Nodal expression and detection in cancer: experience and challenges.

Nodal is a TGF-β-related embryonic morphogen that is expressed in multiple human cancers. Detection of Nodal expression in these tissues can be challenging if issues related to Nodal transcription and protein processing are not considered. Here, we discuss certain characteristics related to Nodal expression and function and how these can facilitate acquisition and interpretation of expression data, contributing to our understanding of the potential role of Nodal in human cancer.

Early events in xenograft development from the human embryonic stem cell line HS181--resemblance with an initial multiple epiblast formation.

Xenografting is widely used for assessing in vivo pluripotency of human stem cell populations. Here, we report on early to late events in the development of mature experimental teratoma from a well-characterized human embryonic stem cell (HESC) line, HS181. The results show an embryonic process, increasingly chaotic.

Concise review: Cord blood banking, transplantation and induced pluripotent stem cell: success and opportunities.

Hematopoietic cell transplantation (HCT) has become a standard practice to treat a number of malignant and nonmalignant hematologic diseases. Bone marrow, mobilized peripheral blood, and umbilical cord blood can all serve as primary sources of cells for HCT. The number of cord blood units currently stored is large, although it represents only a fraction of potential collections.

Injection of human mesenchymal stem cells improves healing of vocal folds after scar excision--a xenograft analysis.

Objectives: Using a xenograft model the aim was to analyze if injection of human mesenchymal stem cells (hMSC) into the rabbit vocal fold (VF), after excision of an established scar, can improve the functional healing of the VF.

Study Design: Prospective design with an experimental xenograft model.

Methods: The VFs of 12 New Zealand rabbits were injured by a bilateral localized resection.

Modeling inherited metabolic disorders of the liver using human induced pluripotent stem cells.

Human induced pluripotent stem (iPS) cells hold great promise for advancements in developmental biology, cell-based therapy, and modeling of human disease. Here, we examined the use of human iPS cells for modeling inherited metabolic disorders of the liver. Dermal fibroblasts from patients with various inherited metabolic diseases of the liver were used to generate a library of patient-specific human iPS cell lines.

Injection of human mesenchymal stem cells improves healing of scarred vocal folds: analysis using a xenograft model.

Objectives/hypothesis: The aims were to analyze if improved histological and viscoelastic properties seen after injection of human mesenchymal stem cells (hMSCs) in scarred vocal folds (VFs) of rabbits are sustainable and if the injected hMSCs survive 3 months in the VFs.

Study Design: Experimental xenograft model.

Methods: Eighteen VFs of 11 New Zealand white rabbits were scarred by a bilateral localized resection.

Lineage-specific promoter DNA methylation patterns segregate adult progenitor cell types.

Mesenchymal stem cells (MSCs) can differentiate into multiple mesodermal cell types in vitro; however, their differentiation capacity is influenced by their tissue of origin. To what extent epigenetic information on promoters of lineage-specification genes in human progenitors influences transcriptional activation and differentiation potential remains unclear. We produced bisulfite sequencing maps of DNA methylation in adipogenic, myogenic, and endothelial promoters in relation to gene expression and differentiation capacity, and unravel a similarity in DNA methylation profiles between MSCs isolated from human adipose tissue, bone marrow (BM), and muscle.

Liver X receptors and oxysterols promote ventral midbrain neurogenesis in vivo and in human embryonic stem cells.

Control over progenitor proliferation and neurogenesis remains a key challenge for stem cell neurobiology and a prerequisite for successful stem cell replacement therapies for neurodegenerative diseases like Parkinson's disease (PD). Here, we examined the function of two nuclear receptors, liver X receptors (Lxralpha and beta) and their ligands, oxysterols, as regulators of cell division, ventral midbrain (VM) neurogenesis, and dopaminergic (DA) neuron development. Deletion of Lxrs reduced cell cycle progression and VM neurogenesis, resulting in decreased DA neurons at birth.

Signaling pathways controlling pluripotency and early cell fate decisions of human induced pluripotent stem cells.

Human pluripotent stem cells from embryonic origins and those generated from reprogrammed somatic cells share many characteristics, including indefinite proliferation and a sustained capacity to differentiate into a wide variety of cell types. However, it remains to be demonstrated whether both cell types rely on similar mechanisms to maintain their pluripotent status and to control their differentiation. Any differences in such mechanisms would suggest that reprogramming of fibroblasts to generate induced pluripotent stem cells (iPSCs) results in novel states of pluripotency.

Melatonin promotes the cumulus-oocyte complexes quality of vitrified-thawed murine ovaries; with increased mean number of follicles survival and ovary size following heterotopic transplantation.

We have tested the protective effect of melatonin on neonate murine ovarian tissue after vitrification, thawing and heterotopic transplantation into ovariectomized recipient mice. Vitrified ovaries from neonate (CBA x C57Bl/6) F1 hybrid mice were thawed under standard condition with or without the addition of 100 microM melatonin. Following transplantation, melatonin (20 mg/kg/day) or saline solution (physiological saline) was injected i.

Species-specific in vivo engraftment of the human BL melanoma cell line results in an invasive dedifferentiated phenotype not present in xenografts.

For clinically relevant studies on melanoma progression and invasiveness, in vivo experimental systems with a human cellular microenvironment would be advantageous. We have compared tumor formation from a human cutaneous malignant melanoma cell line (BL), after injection as conventional xenografts in the mouse, or when injected into a predominantly species-specific environment of human embryonic stem cell-derived teratoma induced in the mouse (the hEST model). The resulting melanoma histology was generally analogous, both systems showing delimited densely packed areas with pleomorphic cells of malignant appearance.

Isolation and production of cells suitable for human therapy: challenges ahead.

Considerable practical hurdles must be overcome prior to the broad application of stem cell therapies. We outline challenges that may vary across different models of cell therapy, including the following broad concepts: issues related to the sourcing of material, and issues related to product manufacturing, shipping, storage and tracking, and standardization.

New ISSCR guidelines underscore major principles for responsible translational stem cell research.

The International Society for Stem Cell Research (ISSCR) task force that developed new Guidelines for the Clinical Translation of Stem Cells discusses core principles that should guide the responsible transition of basic stem cell research into appropriate clinical applications.

Dynamics of gene expression during bone matrix formation in osteogenic cultures derived from human embryonic stem cells in vitro.

Characterization of directed differentiation protocols is a prerequisite for understanding embryonic stem cell behavior, as they represent an important source for cell-based regenerative therapies. Studies have investigated the osteogenic potential of human embryonic stem cells (HESCs), building upon those using pre-osteoblastic cells, however no consensus exists as to whether differentiating HESCs behave in a similar manner to the traditionally used osteoblastic progenitors. Thus, the aim of the current investigation was to define the gene expression pattern of osteoblastic differentiating HESCs, treated with ascorbic acid phosphate, beta-glycerophosphate and dexamethasone over a 25 day period.