Preclinical investigation of anti-tumor efficacy of allogeneic natural killer cells combined with cetuximab for head and neck squamous cell carcinoma.

Head and neck squamous cell carcinoma (HNSCC) presents a significant therapeutic challenge because of the limited effectiveness of current treatments including immunotherapy and chemotherapy. This study investigated the potential of a novel combination therapy using allogeneic natural killer (NK) cells and cetuximab, an anti-epidermal growth factor receptor monoclonal antibody, to enhance anti-tumor efficacy in HNSCC. Allogeneic NK cells were tested against HNSCC cells in vitro and NOG (NOD/Shi-scid/IL-2Rγ null) xenograft mouse models for cytotoxicity.

Treatment of Alzheimer's Disease subjects with expanded non-genetically modified autologous natural killer cells (SNK01): a phase I study.

Background: The importance of natural killer (NK) cells of the innate immune system in neurodegenerative disease has largely been overlooked despite studies demonstrating their ability to reduce neuroinflammation (thought to be mediated by the elimination of activated T cells, degradation of protein aggregates and secretion of anti-inflammatory cytokines). SNK01 is an autologous non-genetically modified NK cell product showing increased activity in vitro. We hypothesized that SNK01 can be safely infused to reduce neuroinflammation in Alzheimer's Disease (AD) patients.

Efficient Neural Differentiation of hPSCs by Extrinsic Signals Derived from Co-cultured Neural Stem or Precursor Cells.

In this study, we found that undifferentiated human pluripotent stem cells (hPSCs; up to 30% of total cells) present in the cultures of neural stem or precursor cells (NPCs) completely disappeared within several days when cultured under neural differentiation culture conditions. Intriguingly, the disappearance of undifferentiated cells was not due to cell death but was instead mediated by neural conversion of hPSCs. Based on these findings, we propose pre-conditioning of donor NPC cultures under terminal differentiation culture conditions as a simple but efficient method of eliminating undifferentiated cells to treat neurologic disorders.

Vitamin C-Induced Epigenetic Modifications in Donor NSCs Establish Midbrain Marker Expressions Critical for Cell-Based Therapy in Parkinson's Disease.

Cultured neural stem/precursor cells (NSCs) are regarded as a potential systematic cell source to treat Parkinson's disease (PD). However, the therapeutic potential of these cultured NSCs is lost during culturing. Here, we show that treatment of vitamin C (VC) enhances generation of authentic midbrain-type dopamine (mDA) neurons with improved survival and functions from ventral midbrain (VM)-derived NSCs.

Neural stem cells secrete factors facilitating brain regeneration upon constitutive Raf-Erk activation.

The intracellular Raf-Erk signaling pathway is activated during neural stem cell (NSC) proliferation, and neuronal and astrocytic differentiation. A key question is how this signal can evoke multiple and even opposing NSC behaviors. We show here, using a constitutively active Raf (ca-Raf), that Raf-Erk activation in NSCs induces neuronal differentiation in a cell-autonomous manner.

LIN28A enhances the therapeutic potential of cultured neural stem cells in a Parkinson's disease model.

The original properties of tissue-specific stem cells, regardless of their tissue origins, are inevitably altered during in vitro culturing, lessening the clinical and research utility of stem cell cultures. Specifically, neural stem cells derived from the ventral midbrain lose their dopamine neurogenic potential, ventral midbrain-specific phenotypes, and repair capacity during in vitro cell expansion, all of which are critical concerns in using the cultured neural stem cells in therapeutic approaches for Parkinson's disease. In this study, we observed that the culture-dependent changes of neural stem cells derived from the ventral midbrain coincided with loss of RNA-binding protein LIN28A expression.

Combined Nurr1 and Foxa2 roles in the therapy of Parkinson's disease.

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Doxycycline supplementation allows for the culture of human ESCs/iPSCs with media changes at 3-day intervals.

Culturing human embryonic stem and induced pluripotent stem cells (hESCs/iPSCs) is one of the most costly and labor-intensive tissue cultures, as media containing expensive factors/cytokines should be changed every day to maintain and propagate undifferentiated hESCs/iPSCs in vitro. We recently reported that doxycycline, an anti-bacterial agent, had dramatic effects on hESC/iPSC survival and promoted self-renewal. In this study, we extended the effects of doxycycline to a more practical issue to save cost and labor in hESC/iPSC cultures.

Vitamin C facilitates dopamine neuron differentiation in fetal midbrain through TET1- and JMJD3-dependent epigenetic control manner.

Intracellular Vitamin C (VC) is maintained at high levels in the developing brain by the activity of sodium-dependent VC transporter 2 (Svct2), suggesting specific VC functions in brain development. A role of VC as a cofactor for Fe(II)-2-oxoglutarate-dependent dioxygenases has recently been suggested. We show that VC supplementation in neural stem cell cultures derived from embryonic midbrains greatly enhanced differentiation toward midbrain-type dopamine (mDA) neurons, the neuronal subtype associated with Parkinson's disease.

Doxycycline enhances survival and self-renewal of human pluripotent stem cells.

We here report that doxycycline, an antibacterial agent, exerts dramatic effects on human embryonic stem and induced pluripotent stem cells (hESC/iPSCs) survival and self-renewal. The survival-promoting effect was also manifest in cultures of neural stem cells (NSCs) derived from hESC/iPSCs. These doxycycline effects are not associated with its antibacterial action, but mediated by direct activation of a PI3K-AKT intracellular signal.

Foxa2 acts as a co-activator potentiating expression of the Nurr1-induced DA phenotype via epigenetic regulation.

Understanding how dopamine (DA) phenotypes are acquired in midbrain DA (mDA) neuron development is important for bioassays and cell replacement therapy for mDA neuron-associated disorders. Here, we demonstrate a feed-forward mechanism of mDA neuron development involving Nurr1 and Foxa2. Nurr1 acts as a transcription factor for DA phenotype gene expression.

Dynamic changes in DNA methylation and hydroxymethylation when hES cells undergo differentiation toward a neuronal lineage.

DNA methylation and hydroxymethylation have been implicated in normal development and differentiation, but our knowledge is limited about the genome-wide distribution of 5-methylcytosine (5 mC) and 5-hydroxymethylcytosine (5 hmC) during cellular differentiation. Using an in vitro model system of gradual differentiation of human embryonic stem (hES) cells into ventral midbrain-type neural precursor cells and terminally into dopamine neurons, we observed dramatic genome-wide changes in 5 mC and 5 hmC patterns during lineage commitment. The 5 hmC pattern was dynamic in promoters, exons and enhancers.

Inhibition of pluripotent stem cell-derived teratoma formation by small molecules.

The future of safe cell-based therapy rests on overcoming teratoma/tumor formation, in particular when using human pluripotent stem cells (hPSCs), such as human embryonic stem cells (hESCs) and human induced pluripotent stem cells (hiPSCs). Because the presence of a few remaining undifferentiated hPSCs can cause undesirable teratomas after transplantation, complete removal of these cells with no/minimal damage to differentiated cells is a prerequisite for clinical application of hPSC-based therapy. Having identified a unique hESC signature of pro- and antiapoptotic gene expression profile, we hypothesized that targeting hPSC-specific antiapoptotic factor(s) (i.

In vitro generation of mature dopamine neurons by decreasing and delaying the expression of exogenous Nurr1.

Neural stem/progenitor cell (NSC/NPC) cultures can be a source of dopamine (DA) neurons for experimental and transplantation purposes. Nurr1, a steroid receptor transcription factor, can overcome the limitations associated with differentiation of cultured NPCs into DA neurons. However, forced Nurr1 expression in NPC cultures generates non-neuronal and/or immature DA cells.

Prolonged membrane depolarization enhances midbrain dopamine neuron differentiation via epigenetic histone modifications.

Understanding midbrain dopamine (DA) neuron differentiation is of importance, because of physiological and clinical implications of this neuronal subtype. We show that prolonged membrane depolarization induced by KCl treatment promotes DA neuron differentiation from neural precursor cells (NPCs) derived from embryonic ventral midbrain (VM). Interestingly, the depolarization-induced increase of DA neuron yields was not abolished by L-type calcium channel blockers, along with no depolarization-mediated change of intracellular calcium level in the VM-derived NPCs (VM-NPCs), suggesting that the depolarization effect is due to a calcium-independent mechanism.

Protein-based human iPS cells efficiently generate functional dopamine neurons and can treat a rat model of Parkinson disease.

Parkinson disease (PD) involves the selective loss of midbrain dopamine (mDA) neurons and is a possible target disease for stem cell-based therapy. Human induced pluripotent stem cells (hiPSCs) are a potentially unlimited source of patient-specific cells for transplantation. However, it is critical to evaluate the safety of hiPSCs generated by different reprogramming methods.

Foxa2 and Nurr1 synergistically yield A9 nigral dopamine neurons exhibiting improved differentiation, function, and cell survival.

Effective dopamine (DA) neuron differentiation from neural precursor cells (NPCs) is prerequisite for precursor/stem cell-based therapy of Parkinson's disease (PD). Nurr1, an orphan nuclear receptor, has been reported as a transcription factor that can drive DA neuron differentiation from non-dopaminergic NPCs in vitro. However, Nurr1 alone neither induces full neuronal maturation nor expression of proteins found specifically in midbrain DA neurons.

Generation of dopamine neurons with improved cell survival and phenotype maintenance using a degradation-resistant nurr1 mutant.

Nurr1 is a transcription factor specific for the development and maintenance of the midbrain dopamine (DA) neurons. Exogenous Nurr1 in neural precursor (NP) cells induces the differentiation of DA neurons in vitro that are capable of reversing motor dysfunctions in a rodent model for Parkinson disease. The promise of this therapeutic approach, however, is unclear due to poor cell survival and phenotype loss of DA cells after transplantation.