• Asian Pacific Journal of Cancer Prevention
• /
• v.13 no.6
• /
• pp.2485-2489
• /
• 2012

Purpose: Notch is an important signaling pathway that regulates cell fate, stem cell maintenance and the initiation of differentiation in many tissues. It has been reported that activation of Notch-1 contributes to tumorigenesis. However, whether Notch signaling might have a role in chemoresistance of prostate cancer is unclear. This study aimed to investigate the effects of Notch-1 silencing on the sensitivity of prostate cancer cells to docetaxel treatment. Methods: siRNA against Notch-1 was transfected into PC-3 prostate cancer cells. Proliferation, apoptosis and cell cycle distribution were examined in the presence or absence of docetaxel by MTT and flow cytometry. Expression of $p21^{waf1/cip1}$ and Akt as well as activation of Akt in PC-3 cells were detected by Western blot and Real-time PCR. Results: Silencing of Notch-1 promoted docetaxel induced cell growth inhibition, apoptosis and cell cycle arrest in PC-3 cells. In addition, these effects were associated with increased $p21^{waf1/cip1}$ expression and decreased Akt expression and activation in PC-3 cells. Conclusion: Notch-1 promotes chemoresistance of prostate cancer and could be a potential therapeutic target.

• Animal cells and systems
• /
• v.6 no.1
• /
• pp.69-74
• /
• 2002

Recent evidence has suggested that trunk neural crest cell generally assumed to have equivalent differentiation potentials, demonstrate differentiation bias along the anterior/posterior axis. In amphibian and fish, neural crest cells give rise to three chromatophore types, melanophores, xantho-phores, and iridophores. Each pigment cell type has distinct characteristics but there is speculation about the cellular plasticity that exists among them. Neural crest cells migrate along specific routes, ventromedially and dorsolaterally. Neural crest cells that travel dorsolaterally are the first cells to begin migration in the axolotl and are the major contributors to the visible pigment pattern. Many factors and mechanisms that are responsible for guiding migratory neural crest cells along potential pathways or determining their fate remain unknown. A single lineage of the crest, which becomes restricted to one of the three pigment cell types, gives us the opportunity to examine the existence of neural crest stem cell populations and cellular plasticity. Study presented here showed results from recent in vitro studies designed to identify parameters influencing differentiation events of individual neural crest-derived pigment cell lineages. Melanophore production from neural crest explants originating from different levels along the anterior/posterior axis of wild type-axolotl embryos were compared and demonstrate that the differentiation of melanophores is enhanced in subpopulation of neural crest treated with forskolin. Forskolin (an adenylate cyclase activator) increases intracellular CAMP concentration and eventually activates the protein kinase-A signaling pathway. Melanophore number, melanin content, and tyrosinase activity in explants taken from the anterior-most region of the crest increased significantly in response to forskolin treatment. This study suggests implications of region specific influences and developmental regulation in the development of pigment pattern.

• The Korean Journal of Physiology and Pharmacology
• /
• v.24 no.6
• /
• pp.463-472
• /
• 2020

Direct reprogramming, also known as a trans-differentiation, is a technique to allow mature cells to be converted into other types of cells without inducing a pluripotent stage. It has been suggested as a major strategy to acquire the desired type of cells in cell-based therapies to repair damaged tissues. Studies related to switching the fate of cells through epigenetic modification have been progressing and they can bypass safety issues raised by the virus-based transfection methods. In this study, a protocol was established to directly convert fully differentiated fibroblasts into diverse mesenchymal-lineage cells, such as osteoblasts, adipocytes, chondrocytes, and ectodermal cells, including neurons, by means of DNA demethylation, immediately followed by culturing in various differentiating media. First, 24 h exposure of 5-azacytidine (5-aza-CN), a well-characterized DNA methyl transferase inhibitor, to NIH-3T3 murine fibroblast cells induced the expression of stem-cell markers, that is, increasing cell plasticity. Next, 5-aza-CN treated fibroblasts were cultured in osteogenic, adipogenic, chondrogenic, and neurogenic media with or without bone morphogenetic protein 2 for a designated period. Differentiation of each desired type of cell was verified by quantitative reverse transcriptase-polymerase chain reaction/western blot assays for appropriate marker expression and by various staining methods, such as alkaline phosphatase/alizarin red S/oil red O/alcian blue. These proposed procedures allowed easier acquisition of the desired cells without any transgenic modification, using direct reprogramming technology, and thus may help make it more available in the clinical fields of regenerative medicine.

• Proceedings of the Korean Institute of Surface Engineering Conference
• /
• 2016.11a
• /
• pp.122.2-122.2
• /
• 2016

Surface topographical cues has been highlighted to control the fate of neural stem cells (NSCs). Herein we developed a hierarchically patterned substrate (HPS) platform for regulating NSC differentiation. The HPS induced cytoskeleton alignment and highly activated focal adhesion in hNSCs as indicated by enhanced expression of focal adhesion proteins such as focal adhesion kinase (FAK) and vinculin. hNSCs cultured on HPS exhibited enhanced neuronal differentiation compared to flat group. We also developed a graphene oxide (GO)-based hierarchically patterned substrates (GPS) that promote focal adhesion formation and neuronal differentiation of hNSCs. Enhanced focal adhesion and differentiation of hNSCs on the HPS was reversed by blocking the ${\beta}1$ integrin binding and mechanotransduction-associated signals including Rho-associated protein kinase (ROCK) and extracellular-regulated kinase (ERK) pathway, which may suggest a potential mechanism of beneficial effects of HPS. In addition, hNSCs on the HPS differentiated into functional neurons exhibiting sodium currents and action potentials as confirmed by whole cell patch-clamping analysis. The hierarchical topography can direct differentiation of NSCs towards functional neurons, and therefore would be an important element for the design of functional biomaterials for neural tissue regeneration applications.

• Reproductive and Developmental Biology
• /
• v.37 no.4
• /
• pp.219-224
• /
• 2013

Muscular satellite cell (SC), which is stem cell of postnatal pig, is an important for study of differentiation into adipogenesis, myogenesis, and osteoblastogenesis. In this study, we isolated and examined from pig muscle tissue to determine capacity in proliferate, differentiate, and expression of various genes. Porcine satellite cells (PSC) were isolated from semimembranosus (SM) muscles of 90~100 days old pigs according to standard conditions. The cell proliferation increased in multi-potent cell by Masson's, oil red O, and Alizarin red staining respectively. We performed the expression levels of differentiation related genes using real-time PCR. We found that the differentiation into adipocyte increased expression levels of both fatty acid binding protein 4 (FABP4) and peroxisome proliferator-activated receptor gamma ($PPAR{\gamma}$) genes (p<0.01). Myocyte increased the expression levels of the myosin heavy chain (MHC), myogenic factor 5 (Myf5), myogenic regulatory factor (MyoD), and Myogenic factor 4 (myogenin) (p<0.01). Osteoblast increased the expression levels of alkaline phosphatase (ALP) (p<0.01). Finally, porcine satellite cells were induced to differentiate towards adipogenic, myogenic, and osteoblastogenic lineages. Our results suggest that muscle satellite cell in porcine may influence cell fate. Understanding the progression of PSC may lead to improved strategies for augmenting meat quality.

• Neonatal Medicine
• /
• v.15 no.1
• /
• pp.22-31
• /
• 2008

Purpose : Bronchopulmonary dysplasia (BPD) is characterized by arrested vascular and alveolar growth in the premature lung. Considering the consequences of arrested lung growth, the idea of administering bone marrow cells to enhance the inborn repair mechanism is promising as this may reduce the morbidity and mortality of BPD. We followed enhanced green fluorescent protein (EGFP)-labeled bone marrow cells (BMC) injected intraperitoneally into non-EGFP mice in order to determine their fate after transplantation. Methods : An angiogenesis inhibitor, SU1498, was injected subcutaneously on day 3 in non-EGFP C57BL/6 newborn mice to create a model of arrested alveolar development. On the following day, $1{\times}10^6$ BMCs isolated from major histocompatibility complex (MHC)- matched syngenic EGFP mice were injected intraperitoneally to non-EGFP BPD mice. Morphometric analysis, immunostaining, and confocal microscopy were performed to determine the fate of EGFP-positive stem cells in the injured lung. Results : SU1498 injection reduced alveolar surface area and mean alveolar volume in newborn mice. BMC injection resulted in recovery of lung structure comparable to controls. EGFP-positive BMCs were identified in the lungs of the recipient mice after intraperitoneal injection. The injected EGFP cells were co-stained with endothelial and epithelial cells of the developing lung as determined by confocal microscopy. Conclusion : Our results illustrated that EGFP-positive BMCs engrafted and trans-differentiated into epithelial and endothelial cells after intraperitoneal injection in a mouse model of arrested alveolar development.

• Journal of Korean Ophthalmic Optics Society
• /
• v.18 no.4
• /
• pp.541-548
• /
• 2013

Purpose: Marrow stromal cells (MSCs) have been known for their potential to trans-differentiate into neural and glial cells in vitro and in vivo. To investigate the influence of the developing host environment on the survival and morphological and molecular differentiation, murine MSCs transplanted into the eye of Brazilian opossum (Monodelphis domestica). Methods: Enhanced green fluorescent protein (GFP) - expressing MSCs were transplanted into developing Brazilian opossums. Animals were allowed to survive for up to 4 weeks after transplantation, at which time the eyes were prepared for immunohistochemical analysis. Results: Some transplanted MSCs survived and showed morphological differentiation into neural cells with some processes within the host vitreous chamber. Some transplanted cells expressed class III ${\beta}$-tubulin (TuJ1, a marker for neuronal cells) or glial fibrillary acid protein (GFAP, a marker for glial cells) or Nestin (a marker for neural stem cells). In addition, some transplanted cells were located in ganglion cell layer but did not show morphological and molecular differentiation. Conclusions: Our result show that the most effective stage of development for transplantation into the retina was postnatal day 16, which retinas developmentally corresponded to postnatal day 4-5 days mouse retina based on cell differentiation and lamination patterns. The present findings suggest that the age of the host appears to play a key role in determining cell fate in vivo.

• Journal of Life Science
• /
• v.32 no.2
• /
• pp.108-118
• /
• 2022

The subventricular zone (SVZ) in the brain contains neural stem cells (NSCs) that generate new neurons throughout one's lifetime. Many extracellular and intracellular factors that affect cell proliferation and neuronal differentiation of NSCs are already well-known. Recently, L-type calcium channels have been reported to regulate neural development and are present in NSCs, differentiating neuroblasts, and mature neurons in the SVZ. Nifedipine, a blocker of L-type calcium channels, has been long used as a therapeutic drug for hypertension. However, studies on the use of nifedipine to inhibit L-type calcium channels of NSCs are lacking. Herein, we treated NSCs cultured from mouse postnatal SVZ with nifedipine during neuronal differentiation. Nifedipine increased the number of Tuj1-positive neurons but did not significantly change the number of Olig2-positive oligodendrocytes. Nifedipine increased cell division during early differentiation, which was detected using the 5-ethynyl-2'-deoxyuridine incorporation assay and immunocytochemistry assessment by staining the cells with phosphorylated histone H3, a mitosis marker. Nifedipine increased the transcription of Dlx2, a neurogenic transcription factor, and the level of Mash1, a marker for early neurogenesis. In addition to nifedipine, verapamil, which is also an L-type calcium channel blocker, showed a slight increase in neurogenesis, but its statistical significance was very low. In contrast, pimozide, a T-type calcium channel blocker, did not affect neurogenesis, although T-type calcium channel genes Cav3.1, Cav3.2, and Cav3.3 were expressed. In summary, nifedipine might promote the neuronal fate of NSCs during early differentiation and calcium signaling through L-type calcium channels might be involved in neuronal differentiation, especially during the early stages of differentiation.