Neural Cell Adhesion Molecule Expression Research Articles

Causal evidence for the involvement of the neural cell adhesion molecule, NCAM, in chronic stress‐induced cognitive impairments

In rodents, chronic stress induces long-lasting structural and functional alterations in the hippocampus, as well as learning and memory impairments. The neural cell adhesion molecule (NCAM) was previously hypothesized to be a key molecule in mediating the effects of stress due to its role in neuronal remodeling and since chronic stress diminishes hippocampal NCAM expression in rats. However, since most of the evidence for these effects is correlative or circumstantial, we tested the performance of conditional NCAM-deficient mice in the water maze task to obtain causal evidence for the role of NCAM. We first validated that exposure to chronic unpredictable stress decreased hippocampal NCAM expression in C57BL/6 wild-type mice, inducing deficits in reversal learning and mild deficits in spatial learning. Similar deficits in water maze performance were found in conditional NCAM-deficient mice that could not be attributed to increased anxiety or enhanced corticosterone responses. Importantly, the performance of both the conditional NCAM-deficient mice and chronically stressed wild-type mice in the water maze was improved by post-training injection of the NCAM mimetic peptide, FGLs. Thus, these findings support the functional involvement of NCAM in chronic stress-induced alterations and highlight this molecule as a potential target to treat stress-related cognitive disturbances.

Impact of maternal separation on neural cell adhesion molecules expression in dopaminergic brain regions of juvenile, adolescent and adult rats

Stressful experiences in the early stages of life can influence brain development and maturation, and they can also increase the risk for some psychiatric disorders; however, the specific mechanisms of this effect are still poorly understood. Neural cell adhesion molecules (NCAM 120, 140, 180kDa) are known to play an important role in normal brain development and synaptic plasticity. Therefore, we decided to investigate whether maternal separation (MS) in rats, a paradigm which models an early life stress, has any impact on the expression of NCAM proteins in the juvenile, adolescent and adult brains of both male and female rats. Specifically, we focused our efforts on the brain regions associated with dopaminergic neurotransmission. In juvenile rats, MS decreased the levels of NCAM-140 in the substantia nigra (SN) of females and NCAM-180 in the ventral tegmental area of males. During adolescence, a reduction in NCAM-180 levels in the SN and medial prefrontal cortex (mPFC) of MS females was revealed. Finally, in adulthood, a decrease in NCAM-180 expression was observed in the mPFC of MS males. The results that we obtained indicate that early life stress can affect maturation and NCAM-driven plasticity in dopaminergic brain areas at different stages of ontogenesis and with a sex-specific manner.

Sequences from the First Fibronectin Type III Repeat of the Neural Cell Adhesion Molecule Allow O-Glycan Polysialylation of an Adhesion Molecule Chimera

Polysialic acid is a developmentally regulated, anti-adhesive polymer that is added to N-glycans on the fifth immunoglobulin domain (Ig5) of the neural cell adhesion molecule (NCAM). We found that the first fibronectin type III repeat (FN1) of NCAM is required for the polysialylation of N-glycans on the adjacent Ig5 domain, and we proposed that the polysialyltransferases recognize specific sequences in FN1 to position themselves for Ig5 N-glycan polysialylation. Other studies identified a novel FN1 acidic surface patch and α-helix that play roles in NCAM polysialylation. Here, we characterize the contribution of two additional FN1 sequences, Pro(510)-Tyr(511)-Ser(512) (PYS) and Gln(516)-Val(517)-Gln(518) (QVQ). Replacing PYS or the acidic patch dramatically decreases the O-glycan polysialylation of a truncated NCAM protein, and replacing the α-helix or QVQ shifts polysialic acid to FN1 O-glycans in full-length NCAM. We also found that the FN1 domain of the olfactory cell adhesion molecule, a homologous but unpolysialylated protein, could partially replace NCAM FN1. Inserting Pro(510)-Tyr(511) eliminated N-glycan polysialylation and enhanced O-glycosylation of an NCAM- olfactory cell adhesion molecule chimera, and inserting other FN1 sequences unique to NCAM, predominantly the acidic patch, created a new polysialyltransferase recognition site. Taken together, our results highlight the role of the FN1 α-helix and QVQ sequences in N-glycan polysialylation and demonstrate that the acidic patch primarily functions in O-glycan polysialylation.

Does Valproic Acid Induce Neuroendocrine Differentiation in Prostate Cancer?

Valproic Acid (VPA) is a histone deacetylase inhibitor that holds promise for cancer therapy. Here, we investigate whether VPA treatment induces neuroendocrine differentiation of Prostate Cancer (PCa). A tissue microarray of VPA-treated and untreated tumor xenografts and cell lines of human PCa (LNCaP, C4-2, DU145, and PC-3) were generated and were analyzed by immunohistochemical analysis (IHC) for NE markers chromogranin A (CgA), synaptophysin, and NCAM (neural cell adhesion molecule). Western blot analysis for CgA was performed to confirm the results of the TMA. IHC analysis did not reveal any induction of CgA, synaptophysin, or NCAM in any xenograft after VPA treatment in vivo. In vitro, VPA treatment induced little synaptophysin expression in C4-2 and PC-3 cells and NCAM expression in LNCaP and PC-3 cells. In the case of CgA, VPA treatment decreased its expression in vitro in a dose-dependent manner, as determined by western blot analysis. Thus our data demonstrates that VPA does not induce NE differentiation of PCa cells in the physiologically relevant in vivo setting.

The inhibitory effect of acrylamide on NCAM expression in human neuroblastoma cells: Involvement of CK2/Ikaros signaling pathway

Acrylamide has been known to have a neurotoxic effect which is associated with nerve damage in both the central and peripheral nervous systems. Since neural cell adhesion molecule (NCAM) plays an important role in the processes of neuronal development and synaptic plasticity, the down-regulation of NCAM may lead impaired spatial memory and reduced long-term potentiation. We examined the effect of acrylamide on NCAM expression and the mechanisms of its effect in human neuroblastoma cells. Treatment with acrylamide resulted in the decrease of NCAM expression, which was reversed by CK2 inhibitor, 4,5,6,7-tetrabromobenzotriazole (TBB). Moreover, Western blot analysis showed that acrylamide induced the expression of CK2. Acrylamide dose-dependently decreased the DNA binding affinity of the Ikaros transcription factor, which is a bifunctional differentiation factor. In addition, the cells treated with acrylamide and CK2 inhibitor showed increased Ikaros activity compared with the acrylamide treatment only. Small interfering RNA-mediated depletion of CK2-α also increased Ikaros activity in acrylamide-treated cells. Overall, these data suggest that acrylamide decreases the Ikaros DNA binding activity via the CK2 pathway, resulting in a decrease of NCAM expression and provide further insight into the mechanisms underlying acrylamide actions.

The expression of PSA-NCAM in pituitary adenomas and its clinical implication

Objective To investigate the expression of polysialylated neural cell adhesion molecule(PSA-NCAM) and its relation with invasion, histology type and Ki-67 antigen. Methods Sixty specimens and clinical data of pituitary adenomas were collected after operation, and 3 cadaveric specimens of normal pituitary tissues were obtained. The expression of PSA-NCAM was detected by immunohistochem-isty. Results The positive expression rate of PSA-NCAM was 52. 6% in all pituitary adenomas, but no expression was detected in normal pituitary tissues. Of 25 male and 36 female patients with pituitary adenoma, the positive expression rate of PSA-NCAM was 44.0% and 41.7% respectively (P>0.05). The mean age was 42. 1 ± 11. 2 in PSA-NCAM expression group, and that was 44. 7 ± 12. 4 in PSA-NCAM no expression group (P>0.05 ). The Ki-67 label index ( Ki-67LI) was(3. 6±1. 3 ) % in PSA-NCAM expression group, and that was (2.7±1.4) % in PSA-NCAM no expression group (P <0. 05). The average tumor width was (2. 5±0. 9) cm in PSA-NCAM expression group, and that was (1.6±1.2) cm in PSA-NCAM no expression group (P<0.05). The positive expression rate of PSA-NCAM was 62. 5% in invasive pituitary adenomas, and that was 20. 7% in no invasive pituitary adenomas (P<0.01). Conclusion The PSA-NCAM expression of pituitary adenomas was related to its size, invasion, and proliferation index, but not to gender and age of the patients. Key words: Pituitary adenoma; Adhesion molecule; Ki-67; Invasion

A peptide derived from a trans‐homophilic binding site in neural cell adhesion molecule induces neurite outgrowth and neuronal survival

The neural cell adhesion molecule (NCAM) plays a key role in neural development, regeneration, and synaptic plasticity. The crystal structure of a fragment of NCAM comprising the three N-terminal immunoglobulin (Ig)-like modules indicates that the first and second Ig modules bind to each other, thereby presumably mediating dimerization of NCAM molecules expressed on the same cell surface (cis-interactions), whereas the third Ig module, through interactions with the first or second Ig module, mediates interactions between NCAM molecules expressed on the surface of opposing cells (trans-interactions). We have designed a new potent peptide ligand of NCAM, termed plannexin, based on a discontinuous sequence in the second NCAM Ig module that represents a homophilic binding site for an opposing third Ig module. The peptide was found by surface plasmon resonance analysis to bind the third NCAM Ig module. It promoted survival of cultured cerebellar granule neurons (CGNs) and also induced neurite extension in cultures of dopaminergic neurons and CGNs; the latter effect was shown to be dependent on NCAM expression, indicating that plannexin mimics the neuritogenic effect of homophilic NCAM binding.

The role of NCAM in auditory fear conditioning and its modulation by stress: a focus on the amygdala

Chronic stress in rodents was shown to induce structural shrinkage and functional alterations in the hippocampus that were linked to spatial memory impairments. Effects of chronic stress on the amygdala have been linked to a facilitation of fear conditioning. Although the underlying molecular mechanisms are still poorly understood, increasing evidence highlights the neural cell adhesion molecule (NCAM) as an important molecular mediator of stress-induced structural and functional alterations. In this study, we investigated whether altered NCAM expression levels in the amygdala might be related to stress-induced enhancement of auditory fear conditioning and anxiety-like behavior. In adult C57BL/6J wild-type mice, chronic unpredictable stress resulted in an isoform-specific increase of NCAM expression (NCAM-140 and NCAM-180) in the amygdala, as well as enhanced auditory fear conditioning and anxiety-like behavior. Strikingly, forebrain-specific conditional NCAM-deficient mice (NCAM-floxed mice that express the cre-recombinase under the control of the promoter of the alpha-subunit of the calcium-calmodulin-dependent protein kinase II), whose amygdala NCAM expression levels are reduced, displayed impaired auditory fear conditioning which was not altered following chronic stress exposure. Likewise, chronic stress in these conditional NCAM-deficient mice did not modify NCAM expression levels in the amygdala or hippocampus, while they showed enhanced anxiety-like behavior, questioning the involvement of NCAM in this type of behavior. Together, our results strongly support the involvement of NCAM in the amygdala in the consolidation of auditory fear conditioning and highlight increased NCAM expression in the amygdala among the mechanisms whereby stress facilitates fear conditioning processes.

Effect of Human Colorectal Carcinogenesis on the Neural Cell Adhesion Molecule Expression and Polysialylation

Objective: Although downregulation of neural cell adhesion molecule (NCAM) has been correlated with poor prognosis in colorectal cancer (CRC), it is also possible that colon cancer spreading comes from reducing tumor cell adhesion through NCAM polysialylation, as occurs in lung carcinoma or Wilms’ tumor. Methods: To prove this hypothesis, we have performed a prospective study on tumor and control specimens from 39 CRC patients, which were immunostained for NCAM and PSA (polysialic acid) expression. Results: Tumor versus control expression of NCAM and PSA epitopes in tissue specimens, as well as correlation between tumor expression and clinicopathological features, were statistically analyzed. Results showed a low constitutive expression of NCAM and PSA (PSA-NCAM) in control tissue, which reached a statistically significant increase in the tumor tissue. Likewise, the presence and number of lymph node metastases at surgery were correlated with NCAM expression and PSA/NCAM coexpression. Conclusions: These data highlight the importance of taking into account PSA-associated epitopes when dealing with NCAM cell expression studies in tumor development and progression. The analysis of PSA and NCAM expression in CRC suggests a new way, other than downregulation of NCAM, in order to escape contact inhibition and promote cell tumor spreading in colorectal cancer.

Electrical stimulation impairs early functional recovery and accentuates skeletal muscle atrophy after sciatic nerve crush injury in rats

Neuromuscular recovery after peripheral nerve lesion depends on the regeneration of severed axons that re-establish their functional connection with the denervated muscle. The aim of this study was to determine the effects of electrical stimulation (ES) on the neuromuscular recovery after nerve crush injury in rats. Electrical stimulation was carried out on the tibialis anterior (TA) muscle after sciatic nerve crush injury in a rat model. Six ES sessions were administered every other day starting from day 3 postinjury until the end of the experiment (day 14). The sciatic functional index was calculated. Muscle excitability, neural cell adhesion molecule (N-CAM) expression, and muscle fiber cross-sectional area (CSA) were accessed from TA muscle. Regenerated sciatic nerves were analyzed by light and confocal microscopy. Both treated (crush+ES) and untreated (crush) groups had their muscle weight and CSA decreased compared with the normal group (P < 0.05). Electrical stimulation accentuated muscle fiber atrophy more in the crush+ES than in the crush group (P < 0.05). N-CAM expression increased in both crush and crush+ES groups compared with the normal group (P < 0.05). Regenerated nerves revealed no difference between the crush and crush+ES groups. Nevertheless, functional recovery at day 14 post-injury was significantly lower in crush+ES group compared with the crush group. In addition, the crush+ES group had chronaxie values significantly higher on days 7 and 13 compared with the crush group, which indicates a decrease in muscle excitability in the crush+ES animals. The results of this study do not support a benefit of the tested protocol of ES during the period of motor nerve recovery following injury.

Neural Cell Adhesion Molecule-Associated Polysialic Acid Regulates Synaptic Plasticity and Learning by Restraining the Signaling through GluN2B-Containing NMDA Receptors

The neural cell adhesion molecule (NCAM) is the predominant carrier of alpha2,8 polysialic acid (PSA) in the mammalian brain. Abnormalities in PSA and NCAM expression are associated with schizophrenia in humans and cause deficits in hippocampal synaptic plasticity and contextual fear conditioning in mice. Here, we show that PSA inhibits opening of recombinant NMDA receptors composed of GluN1/2B (NR1/NR2B) or GluN1/2A/2B (NR1/NR2A/NR2B) but not of GluN1/2A (NR1/NR2A) subunits. Deficits in NCAM/PSA increase GluN2B-mediated transmission and Ca(2+) transients in the CA1 region of the hippocampus. In line with elevation of GluN2B-mediated transmission, defects in long-term potentiation in the CA1 region and contextual fear memory in NCAM/PSA-deficient mice are abrogated by application of a GluN2B-selective antagonist. Furthermore, treatment with the glutamate scavenger glutamic-pyruvic transaminase, ablation of Ras-GRF1 (a mediator of GluN2B signaling to p38 MAPK), or direct inhibition of hyperactive p38 MAPK can restore impaired synaptic plasticity in brain slices lacking PSA/NCAM. Thus, PSA carried by NCAM regulates plasticity and learning by inhibition of the GluN2B-Ras-GRF1-p38 MAPK signaling pathway. These findings implicate carbohydrates carried by adhesion molecules in modulating NMDA receptor signaling in the brain and demonstrate reversibility of cognitive deficits associated with ablation of a schizophrenia-related adhesion molecule.

Stretching and electrical stimulation reduce the accumulation of MyoD, myostatin and atrogin-1 in denervated rat skeletal muscle

Denervation causes muscle atrophy and incapacity in humans. Although electrical stimulation (ES) and stretching (St) are commonly used in rehabilitation, it is still unclear whether they stimulate or impair muscle recovery and reinnervation. The purpose of this study was to evaluate the effects of ES and St, alone and combined (ES + St), on the expression of genes that regulate muscle mass (MyoD, Runx1, atrogin-1, MuRF1 and myostatin), on muscle fibre cross-sectional area and excitability, and on the expression of the neural cell adhesion molecule (N-CAM) in denervated rat muscle. ES, St and ES + St reduced the accumulation of MyoD, atrogin-1 and MuRF1 and maintained Runx1 and myostatin expressions at normal levels in denervated muscles. None of the physical interventions prevented muscle fibre atrophy or N-CAM expression in denervated muscles. In conclusion, although ES, St and ES + St changed gene expression, they were insufficient to avoid muscle fibre atrophy due to denervation.

The neural cell adhesion molecule is involved in the metastatic capacity in a murine model of lung cancer

Neural cell adhesion molecule (NCAM) is involved in cell growth, migration, and differentiation. Its expression and/or polysialylation appear to be deregulated in many different cancer types. We employed the lung tumor cell line LP07, syngeneic in BALB/c mice to investigate the role of NCAM in malignant progression. LP07 cells express the three main NCAM isoforms, all of them polysialylated. This cells line, pretreated with an anti-NCAM antibody and inoculated intravenously (i.v.) into syngeneic mice, developed less and smaller lung metastases. In vitro studies showed that NCAM bound antibody inhibited cell growth, mainly due to an increase in apoptosis, associated with a decrease of cyclin D1 and enhanced expression of active caspase 3 and caspase 9. Anti-NCAM-treated LP07 cells showed impairment in their ability to migrate and adhere to several extracellular matrix components. Secreted uPA activity was also reduced. NCAM-140 knocked-down by siRNA in LP07 cells pretreated or not with anti-NCAM showed an impaired metastasizing ability upon i.v. inoculation into mice. These results suggest that anti-NCAM treatment could be mimicking homophilic trans-interactions and NCAM-140 knocked-down impairs heterophilic interactions, both leading to inhibition of metastatic dissemination. The involvement of NCAM in lung tumor progression was confirmed in human NSCLC tumors. Sixty percent of the cases expressed NCAM at tumor cell level. A multivariate analysis indicated that NCAM expression was associated with a shorter overall survival in this homogeneous series of Stages I and II NSCLC patients. NCAM may be able to modulate mechanisms involved in lung carcinoma progression and represents an attractive target to control metastatic progression.

Angiogenesis and blood vessel stability in inflammatory arthritis

To assess blood vessel stability in inflammatory synovial tissue (ST) and to examine neural cell adhesion molecule (NCAM), oxidative DNA damage, and hypoxia in vivo. Macroscopic vascularity and ST oxygen levels were determined in vivo in patients with inflammatory arthritis who were undergoing arthroscopy. Vessel maturity/stability was quantified in matched ST samples by dual immunofluorescence staining for factor VIII (FVIII)/alpha-smooth muscle actin (alpha-SMA). NCAM and 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG) were examined by immunohistochemistry. Angiogenesis was assessed in vitro, using human dermal endothelial cells (HDECs) in a Matrigel tube formation assay. A significant number of immature vessels (showing no pericyte recruitment) was observed in tissue from patients with inflammatory arthritis (P < 0.001), in contrast to osteoarthritic and normal tissue, which showed complete recruitment of pericytes. Low in vivo PO(2) levels in the inflamed joint (median [range] 22.8 [3.2-54.1] mm Hg) were inversely related to increased macroscopic vascularity (P < 0.04) and increased microscopic expression of FVIII and alpha-SMA (P < 0.04 and P < 0.03, respectively). A significant proportion of vessels showed focal expression of NCAM and strong nuclear 8-oxodG expression, implicating a loss of EC-pericyte contact and increased DNA damage, levels of which were inversely associated with low in vivo PO(2) (P = 0.04 for each comparison). Circulating cells were completely negative for 8-oxodG. Exposure of HDEC to 3% O(2) (reflecting mean ST in vivo measurements) significantly increased EC tube formation (P < 0.05). Our findings indicate the presence of unstable vessels in inflamed joints associated with hypoxia, incomplete EC-pericyte interactions, and increased DNA damage. These changes may further contribute to persistent hypoxia in the inflamed joint to further drive this unstable microenvironment.

Pathological classification of intrahepatic cholangiocarcinoma based on a new concept

Intrahepatic cholangiocarcinoma (ICC) arises from the lining epithelium and peribiliary glands of the intrahepatic biliary tree and shows variable cholangiocytic differentiation. To date, ICC was largely classified into adenocarcinoma and rare variants. Herein, we propose to subclassify the former, based on recent progress in the study of ICC including the gross classification and hepatic progenitor/stem cells and on the pathological similarities between biliary and pancreatic neoplasms. That is, ICC is classifiable into the conventional (bile duct) type, the bile ductular type, the intraductal neoplasm type and rare variants. The conventional type is further divided into the small duct type (peripheral type) and large bile duct type (perihilar type). The former is a tubular or micropapillary adenocarcinoma while the latter involves the intrahepatic large bile duct. Bile ductular type resembles proliferated bile ductules and shows a replacing growth of the hepatic parenchyma. Hepatic progenitor cell or stem cell phenotypes such as neural cell adhesion molecule expression are frequently expressed in the bile ductular type. Intraductal type includes papillary and tubular neoplasms of the bile duct (IPNBs and ITNBs) and a superficial spreading type. IPNB and ITNB show a spectrum from a preneoplastic borderline lesion to carcinoma and may have pancreatic counterparts. At invasive sites, IPNB is associated with the conventional bile duct ICC and mucinous carcinoma. Biliary mucinous cystic neoplasm with ovarian-like stroma in its wall is different from IPNB, particularly IPNB showing cystic dilatation of the affected ducts. Rare variants of ICC include squamous/adenosquamous cell carcinoma, mucinous/signet ring cell carcinoma, clear cell type, undifferentiated type, neuroendocrine carcinoma and so on. This classification of ICC may open up a new field of research of ICC and contribute to the clinical approach to ICC.

Expression of Nestin, Vimentin, and NCAM by Renal Interstitial Cells after Ischemic Tubular Injury

This work explores the distribution of various markers expressed by interstitial cells in rat kidneys after ischemic injury (35 minutes) during regeneration of S3 tubules of outer stripe of outer medulla (OSOM). Groups of experimental animals (n = 4) were sacrificed every two hours during the first 24 hours post-ischemia as well as 2, 3, 7, 14 days post-ischemia. The occurrence of lineage markers was analyzed on kidney sections by immunohistochemistry and morphometry during the process of tubular regeneration. In postischemic kidneys, interstitial cell proliferation, assessed by 5-bromo-2′-deoxyuridine (BrdU) and Proliferating Cell Nuclear Antigen (PCNA) labeling, was prominent in outer medulla and reach a maximum between 24 and 72 hours after reperfusion. This population was characterized by the coexpression of vimentin and nestin. The density of -Neural Cell Adhesion Molecule (NCAM) positive interstitial cells increased transiently (18–72 hours) in the vicinity of altered tubules. We have also localized a small population of α-Smooth Muscle Actin (SMA)-positive cells confined to chronically altered areas and characterized by a small proliferative index. In conclusion, we observed in the postischemic kidney a marked proliferation of interstitial cells that underwent transient phenotypical modifications. These interstitial cells could be implicated in processes leading to renal fibrosis.

Boundary Cap Cells are Highly Competitive for CNS Remyelination: Fast Migration and Efficient Differentiation in PNS and CNS Myelin-Forming Cells

During development, boundary cap cells (BC) and neural crest cell (NCC) derivatives generate Schwann cells (SC) of the spinal roots and a subpopulation of neurons and satellite cells in the dorsal root ganglia. Despite their stem-like properties, their therapeutic potential in the diseased central nervous system (CNS) was never explored. The aim of this work was to explore BC therapeutic potential for CNS remyelination. We derived BC from Krox20(Cre) x R26R(Yfp) embryos at E12.5, when Krox20 is exclusively expressed by BC. Combining microdissection and cell fate mapping, we show that acutely isolated BC are a unique population closely related but distinct from NCC and SC precursors. Moreover, when grafted in the demyelinated spinal cord, BC progeny expands in the lesion through a combination of time-regulated processes including proliferation and differentiation. Furthermore, when grafted away from the lesion, BC progeny, in contrast to committed SC, show a high migratory potential mediated through enhanced interactions with astrocytes and white matter, and possibly with polysialylated neural cell adhesion molecule expression. In response to demyelinated axons of the CNS, BC progeny generates essentially myelin-forming SC. However, in contact with axons and astrocytes, some of them generate also myelin-forming oligodendrocytes. There are two primary outcomes of this study. First, the high motility of BC and their progeny, in addition to their capacity to remyelinate CNS axons, supports the view that BC are a reservoir of interest to promote CNS remyelination. Second, from a developmental point of view, BC behavior in the demyelinated CNS raises the question of the boundary between central and peripheral myelinating cells.

ERK signalling pathway is not involved in PSANCAM-dependent alterations of hippocampal plasticity evoked by CB1 receptor activation

The present study investigated the potential role of the extracellular signal-regulated kinase (ERK) pathway in the alternation of polysialylated neural cell adhesion molecule (PSA-NCAM) expression and proliferation rates in the dentate gyrus (DG) evoked by activation of the CB1 receptor. When given at a dose of 0.1mg/kg, the CB1 receptor agonist, 3-(1,1-dimethylheptyl)-11-hydroxy-Δ8-tetrahydrocannabinol (HU-210), increased the levels of the phosphorylated forms of ERK (pERK1 and pERK2) in the hippocampus when measured 30 min after injection. This HU-210-induced effect was inhibited by α-(amino[(4-aminophenyl)thio]methylene}-2-(trifluoromethyl) benzeneacetonitrile (SL327, 30mg/kg) – an inhibitor of mitogen-activated protein kinase kinase (MEK1/2), the upstream kinase of ERK – given 1h before HU-210 administration. Additionally, SL327 alone significantly attenuated the basal level of both pERK1 and pERK2. HU-210 (0.1mg/kg) decreased the number of PSA-NCAM-immunoreactive (IR) cells but did not affect the rate of proliferation, which was analyzed as the number of Ki-67-IR cells measured in the DG 2 days after HU-210 administration. The data indicated that SL327 (30mg/kg) alone decreased the number of PSA-NCAM-IR cells 2 days after treatment. Joint administration of SL327 and HU-210 decreased the number of PSA-NCAM cells more robustly than did the administration of either alone. In addition, SL327 did not decrease the number of Ki-67-IR cells, while pretreatment with SL32 7 1h before HU-210 administration did. These results suggest that stimulation of the ERK cascade caused by CB1 receptor activation is not involved in hippocampal plasticity governed by PSA-NCAM expression.

Growth pattern in the muscular layer reflects the biological behaviour of colorectal cancer

To determine the clinical value of evaluating the cancer morphology in muscularis propria (MP) for colorectal cancer (CRC) patients. A total of 994 patients with advanced CRC were reviewed in terms of two distinctive growth patterns in the MP: (i) horizontal spread between the circular and longitudinal muscle layers (H-spread) and (ii) 'streaming' spread between the muscle bundles of the circular muscle layer (S-spread). The incidence of H-spread (n = 153) and S-spread (n = 150) showed a positive correlation with tumour-node-metastasis (TNM) stage and both exerted a negative impact on postoperative survival. Adverse morphology in the MP (H-spread and/or S-spread) was consistent with a high grade of vascular invasion and budding in the extramural layer, as also with unfavourable fibrotic stromas in the reactive fibrous zone; the 5-year survival rate in patients with such features was 64.2%, which was lower than that in those without (86.5%, P < 0.0001). Multivariate analysis demonstrated that adverse morphology was an independent prognostic determinant, along with T- and N -stage. As the mode of H-spread, perineural invasion in the myenteric plexus was found to be predominant over lymphatic spread on the basis of S100 and CD34 immunostaining, but neural cell adhesion molecule expression, whether on cancer cells or on neural cells, was not significant for this growth pattern. A particular group of CRCs ingeniously utilizes the thin space between muscle fascicles for development in the MP. Although the biological mechanism remains unknown, this distinctive growth pattern could be a useful indicator to identify CRC patients at high risk of recurrence.

NCAM expression induces neurogenesis in vivo

Neural cell adhesion molecule (NCAM) plays an important role during neural development and in the adult brain, whereby most functions of NCAM have been ascribed to its unique polysialic acid (PSA) modification. Recently we presented evidence suggesting that expression of NCAM in vivo interferes with the maintenance of forebrain neuronal stem cells. We here aimed at investigating the fate of cells generated from NCAM-overexpressing stem cells in postnatal mouse brain and at elucidating the functional domains of NCAM mediating this effect. We show that ectopic expression of the NCAM140 isoform in radial glia and type C cells induces an increase in cell proliferation and consequently the presence of additional neuronal type A cells in the rostral migratory stream. A mutant NCAM protein comprising only fibronectin type III repeats and immunoglobulin-like domain 5 was sufficient to induce this effect. Furthermore, we show that the neurogenic effect is independent of PSA, as transgenic NCAM is not polysialylated in radial glia and type C cells. These results suggest that heterophilic interactions of NCAM with other components of the cell membrane must be involved.