OBJECTIVETo establish the co-culture model of cancer cells and nerve, and to study the influence of esophageal cancer on nerve fibers.

METHODSMouse dorsal root ganglion (DRG) was cultured in sterile conditions by primary isolation. Co-culture model was established using matrigel matrix-embedded DRG and EC109 (esophageal cancer cell line) transfected with green fluorescent protein. Morphological changes of DRG, number and area of neurites were quantified with microscopy and image analysis. Furthermore, the mRNA expression of nerve growth factor(NGF) and brain derived neurotrophic factor(BDNF) was detected by real-time PCR.

RESULTSIn mixture cultivation model of EC109 and DRG cells, directional outgrowth of neurite projecting to EC109 was observed, and the length of neurite was markedly longer in proximal field compared to distal field. The number and area of neurite were 87 and 346 μm(2) in proximal field respectively, and 23 and 141 μm(2) in distal field on the 7th day. The expressions of NGF and BDNF were up-regulated in esophageal cancer cells.

CONCLUSIONSThe esophageal cancer may play an important role in nerve fiber growth and guidance, which may be associated with the up-regulation of NGF and BDNF expressions.

Animals ; Coculture Techniques ; Esophageal Neoplasms ; metabolism ; Ganglia, Spinal ; Humans ; Neurites ; Rats, Sprague-Dawley ; Up-Regulation

OBJECTIVETo investigate the role of iASPP as the target gene of miR-124a in neural development.

METHODSUsing the online bioinformatical tool (TargetScan) and by reviewing the relevant studies, we selected iASPP as the candidate target gene of miR-124a involved in early-stage neuronal differentiation. Luciferase reporter assay was used to verify the candidate gene. We transfected M17 cells with a miR-124a overexpression plasmid and detected the changes in the protein expression of iASPP using Western blotting. With retinoic acid-induced M17 cells as the neuronal differentiation model, the role of iASPP in early-stage neuronal differentiation was investigated by gene overexpression and gene interference techniques.

RESULTSmiR-124a inhibited the expression of iASPP in M17 cells by interacting with the 3'UTR of iASPP gene. miR-124a promoted neurite outgrowth of the cells, which was blocked by iASPP overexpression.

CONCLUSIONmiR-124a promotes neurite outgrowth of M17 cells by inhibiting iASPP expression.

3' Untranslated Regions ; Gene Expression ; Humans ; Intracellular Signaling Peptides and Proteins ; genetics ; metabolism ; MicroRNAs ; genetics ; Neurites ; metabolism ; Repressor Proteins ; genetics ; metabolism ; Transfection

Homophilic interaction of the L1 family of cell adhesion molecules plays a pivotal role in regulating neurite outgrowth and neural cell networking in vivo. Functional defects in L1 family members are associated with neurological disorders such as X-linked mental retardation, multiple sclerosis, low-IQ syndrome, developmental delay, and schizophrenia. Various human tumors with poor prognosis also implicate the role of L1, a representative member of the L1 family of cell adhesion molecules, and ectopic expression of L1 in fibroblastic cells induces metastasis-associated gene expression. Previous studies on L1 homologs indicated that four N-terminal immunoglobulin-like domains form a horseshoe-like structure that mediates homophilic interactions. Various models including the zipper, domain-swap, and symmetry-related models are proposed to be involved in structural mechanism of homophilic interaction of the L1 family members. Recently, cryo-electron tomography of L1 and crystal structure studies of neurofascin, an L1 family protein, have been performed. This review focuses on recent discoveries of different models and describes the possible structural mechanisms of homophilic interactions of L1 family members. Understanding structural mechanisms of homophilic interactions in various cell adhesion proteins should aid the development of therapeutic strategies for L1 family cell adhesion molecule-associated diseases.
Cell Adhesion ; Crystallography, X-Ray ; Escherichia coli ; Humans ; Immunoglobulins/chemistry ; Neural Cell Adhesion Molecule L1/*chemistry/*metabolism ; *Neurites/chemistry/metabolism ; Protein Conformation ; *Protein Interaction Domains and Motifs

The present study was designed to investigate the role of quercetin on neurite growth in N1E-115 cells and the underlying mechanisms. Quercetin was evaluated for its effects on cell numbers of neurites, neurite length, intracellular cAMP content, and Gap-43 expression in N1E-115 cells in vitro by use of microscopy, LANCE(tm) cAMP 384 kit, and Western blot analysis, respectively. Our results showed that quercetin could increase the neurite length in a concentration-dependent manner, but had no effect on the numbers of cells. Quercetin significantly increased the expression of cellular cAMP in a time- and concentration-dependent manner. The Gap-43 expression was up-regulated in a time-dependent manner. In conclusion, quercetin could promote neurite growth through increasing the intracellular cAMP level and Gap-43 expression.
Cell Line ; Cyclic AMP ; metabolism ; GAP-43 Protein ; metabolism ; Nerve Regeneration ; Neurites ; drug effects ; Plant Extracts ; pharmacology ; Quercetin ; pharmacology ; Signal Transduction

OBJECTIVETo study the role of adaptor protein Dok6 in neurite outgrowth in PC12 cells.

METHODSSeries of fusion clones were constructed by fusing different domains of Dok6 into mutant TrkC/Y516F. These constructs were transiently transfected into PC12 cells separately and the expression levels of fusion proteins were detected by Western blot. Neurite outgrowth in these PC12 cells was tested after stimulation of NT-3.

RESULTSEach fusion clone was stably expressed in PC12 cells. The fusion clones that fused both TrkC/Y516F-Dok6 (PTB+C) and TrkC/Y516F-Dok6C rescued the loss of neurite outgrowth in PC12 cells resulting from the mutation in tyrosine 516, while fusion clones that fused with single TrkC/Y516F-Dok6PTB did not show such effect.

CONCLUSIONDok6 can promote neurite outgrowth induced by NT-3 stimulation through its C-terminal in TrkC-positive PC12 cells.

Adaptor Proteins, Signal Transducing ; genetics ; metabolism ; Animals ; Neurites ; drug effects ; physiology ; Neurotrophin 3 ; pharmacology ; PC12 Cells ; Rats ; Receptor, trkC ; metabolism ; Transfection

Lysophosphatidylcholine (LPC) is a bioactive lipid generated by phospholipase A2-mediated hydrolysis of phosphatidylcholine. In the present study, we demonstrate that LPC stimulates phospholipase D2 (PLD2) activity in rat pheochromocytoma PC12 cells. Serum deprivation induced cell death of PC12 cells, as demonstrated by decreased viability, DNA fragmentation, and increased sub-G1 fraction of cell cycle. LPC treatment protected PC12 cells partially from the cell death and induced neurite outgrowth of the cells. Overexpression of PLD2 drastically enhanced the LPC-induced inhibition of apoptosis and neuritogenesis. Pretreatment of the cells with 1-butanol, a PLD inhibitor, completely abrogated the LPC-induced inhibition of apoptosis and neurite outgrowth in PC12 cells overexpressing PLD2. These results indicate that LPC possesses the neurotrophic effects, such as anti-apoptosis and neurite outgrowth, through activation of PLD2.
Starvation ; Rats ; Phospholipase D/antagonists & inhibitors/*metabolism ; PC12 Cells ; Neurites/*drug effects ; Lysophosphatidylcholines/*pharmacology ; Cell Survival/drug effects ; Apoptosis/*drug effects ; Animals

OBJECTIVETo establish an in vitro model of perineural invasion (PNI) with co-culture of human pancreatic cancer cells and rat root ganglion, to observe the neurite outgrowth and pancreatic cancer cell proliferation and migration, and to explore the molecular basis of perineural invasion (PNI) of pancreatic cancer.

METHODSHuman pancreatic cancer cell line (MIA PaCa-2) and rat dorsal root ganglion (DRG) were co-cultured in Matrigel matrix to generate the PNI model. The neurite outgrowth, pancreatic cancer cell colony formation, neurite-colony contact and retrograde migration were observed under an inverted microscope. The data were analyzed with the Image-Pro Plus 5.0 system. The proliferative index (PI) was measured by immunohistochemical staining with the Ki-67 antibody. In order to determine the absorbance (A) of the pancreatic cancer cells, MTT assay was used. The apoptotic index (AI) was evaluated by flow cytometry.

RESULTSNeurite outgrowth was stimulated in the presence of pancreatic cancer cells. After 72 hours of the co-culture, MIA PaCa colonies co-cultured with DRG exhibited a significantly larger colony area (242.83 ± 4.92) than that of the control (182.50 ± 5.39, P < 0.001). In the MIA PaCa-2/DRG co-culture system, the neurites exhibited a trend of growing towards the pancreatic cancer cell colony. However, the pancreatic cancer cells showed a trend of retrogradely migrating to the DRG along the neurite outgrowth, when MIA PaCa-2 colonies touched the DRG. The positive rate of Ki-67 nuclear antigen was significantly higher than in the co-culture group. The PI value was higher in the experimental group (12.80%) than that in the control group (6.81%, P < 0.01). The MTT assay showed that proliferation of the pancreatic cancer cells was more active than that in the control group. Flow cytometry analysis showed that the apoptosis rate of the pancreatic cancer cell was 2.46%, significantly lower than that of the control group (4.89%, P < 0.001).

CONCLUSIONSAn in vitro co-culture model of rat dorsal root ganglion and human pancreatic cancer cell line is successfully established in this study. This MIA PaCa-2/DRG co-culture system demonstrates that the neural-pancreatic carcinoma cell interaction is a mutually beneficial process for the growth of neurites and pancreatic carcinoma cells. The pancreatic cancer cells show a trend of migrating to the DRG along the neurite outgrowth.

Animals ; Apoptosis ; Cell Communication ; Cell Line, Tumor ; Cell Movement ; Cell Proliferation ; Coculture Techniques ; Ganglia, Spinal ; cytology ; metabolism ; Humans ; Neoplasm Invasiveness ; Neurites ; physiology ; Pancreatic Neoplasms ; pathology ; Rats ; Rats, Wistar

In the experiment, we designed and synthesized two siRNAs based on the sequence of nuclear receptor-related factor 1 (Nurr1) mRNA. They were separately subcloned into the plasmid of pSilenCircle (pSC) containing U6 promoter. The pSC-Nurr1 vectors (pSC-N1 and pSC-N2) specific to Nurr1 gene and the negative control vector of short-hairpin RNA (shRNA) eukaryotic expression vector were constructed. We cultured the dopaminergic cell line MN9D and the verified vectors were transfected with LipofectamineTM 2000 in vitro. The positive cell clones transfected with pSC were obtained after being screened with 500 mug/ml G418. After that, the silencing effects of Nurr1 and TH mRNA or protein were detected by real time RT-PCR and Western blot. The neurite extension of MN9D cells was observed and photographed by inverted microscope. The results showed that Nurr1 mRNA expression in MN9D cells was specifically down-regulated by the vectors of pSC-N1 and pSC-N2, and the silencing effects were 62.3% and 45.6%, respectively. The dopaminergic phenotype of TH mRNA was also suppressed significantly and the silencing effects were 76.3% and 62.6%, respectively. Meanwhile, the expressions of Nurr1 and TH proteins were also significantly suppressed, and the silencing effects of Nurr1 and TH protein were 57.4%, 72.0% and 79.1%, 70.1% respectively. The negative control and liposome groups had no effect on the two genes. In conclusion, Nurr1 shRNA expressing vectors can inhibit the expressions of Nurr1 and TH mRNA or protein in MN9D cells, and Nurr1 might play a role in neurite extension of MN9D cells. Nurr1 shRNA expressing vector may provide a novel applicable strategy for the study on the function of the genes associated with Parkinson disease and the development of dopaminergic neuron.
Cell Line ; Dopaminergic Neurons ; cytology ; metabolism ; Down-Regulation ; Fetus ; Humans ; Mesencephalon ; cytology ; Neurites ; physiology ; Nuclear Receptor Subfamily 4, Group A, Member 2 ; genetics ; metabolism ; RNA, Messenger ; genetics ; metabolism ; RNA, Small Interfering ; genetics ; Transfection ; Tyrosine 3-Monooxygenase ; genetics ; metabolism

Small ubiquitin-related modifiers (SUMOs) belong to an important class of ubiquitin like proteins. SUMOylation is a post-translational modification process that regulates the functional properties of many proteins, among which are several proteins implicated in neurodegenerative diseases. This study was aimed to investigate the changes of SUMO-1 expression and modification, and the relationship between SUMO-1 and Alzheimer's disease (AD) pathology in APP/PS1 transgenic AD mice. Using Western blot, co-immunoprecipitation and immunofluorescent staining methods, the SUMO-1 expression and modification and its relation to tau, amyloid precursor protein (APP) and β-amyloid protein (Aβ) in the 12-month-old APP/PS1 transgenic AD mice were analyzed. The results showed that: (1) Compared with the normal wild-type mice, the expression and modification of SUMO-1 increased in brain of AD mice, which was accompanied by an increase of ubiquitination; (2) In RIPA soluble protein fraction of cerebral cortex, co-immunoprecipitation analysis showed tau SUMOylated by SUMO-1 increased in AD mice, however, AT8 antibody labeled phosphorylated tau was less SUMOylated whereas PS422 antibody labeled phosphorylated tau was similar to control mice; (3) Double immunofluorescent staining showed that SUMO-1 could distributed in amyloid plaques, appearing that some of SUMO-1 diffused in centre of some plaques and some of SUMO-1 co-localized with AT8 labeled phosphorylated tau forming punctate aggregates around amyloid plaques which was concerned as dystrophic neurites, however, less Aβ, APP and PS422 labeled phosphorylated tau were found co-localized with SUMO-1. These results suggest that SUMO-1 expression and modification increase abnormally in transgenic AD mice, which may participate in modulation of the formation of senile plaques and dystrophic neurites.
Alzheimer Disease ; physiopathology ; Amyloid beta-Peptides ; metabolism ; Amyloid beta-Protein Precursor ; metabolism ; Animals ; Brain ; pathology ; Mice ; Mice, Transgenic ; Neurites ; pathology ; Phosphorylation ; Plaque, Amyloid ; physiopathology ; SUMO-1 Protein ; metabolism ; Sumoylation ; tau Proteins ; metabolism

To investigate the potential ability of the nitrite to induce neuronal differentiation of PC12 cells, cultured PC12 cells planted on matrigel in the presence or absence of sodium nitrite were employed as model, nerve growth factor (NGF) served as a positive control. After 48 h, sodium nitrite enhanced cell viability and vascular endothelial growth factor (VEGF) secretion. Same as the effect of NGF, sodium nitrite (1.4 mmol x L(-1)) treated cultures contained a greater proportion of cells bearing neurites and neurites were much longer than those found in negative control cultures (P < 0.05). Compared with the negative control, sodium nitrite (1.4 mmol x L(-1)) also upregulated the expression of VEGF mRNA (P < 0.05) and hypoxia inducible factor 1 alpha (HIF-1 alpha) or VEGF protein expression (P < 0.05) in cultures of PC12 cells. On the other hand, these effects of the sodium nitrite were likely mediated by HIF-1alpha, since their effects were antagonized by addition of HIF-1alpha inhibitor YC-1. Taken together, these results suggest that low doses of sodium nitrite could induce neurite outgrowth in PC12 cells by activating the HIF-1alpha-VEGF pathway.
Animals ; Cell Differentiation ; drug effects ; Cell Survival ; drug effects ; Food Preservatives ; pharmacology ; Hypoxia-Inducible Factor 1, alpha Subunit ; genetics ; metabolism ; Neurites ; drug effects ; PC12 Cells ; RNA, Messenger ; metabolism ; Rats ; Sodium Nitrite ; pharmacology ; Up-Regulation ; Vascular Endothelial Growth Factor A ; genetics ; secretion