Contribution of the neural cell recognition molecule NB‐3 to synapse formation between parallel fibers and Purkinje cells in mouse

The neural cell recognition molecule NB‐3, also referred to as contactin‐6, is expressed prominently in the developing nervous system after birth and its deficiency has been shown to cause impairment in motor coordination. Here, we investigated the contribution of NB‐3 to cerebellar development, focusing on lobule 3 where NB‐3 was expressed in granule cells but not in Purkinje cells. In the developing molecular layer, the neural cell recognition molecules TAG‐1, L1, and NB‐3 formed distinct expression zones from the external granule cell layer to the internal granule cell layer (IGL), respectively. The NB‐3‐immunoreactive zone did not overlap with TAG‐1‐immunoreactive zone. By contrast, the L1‐immunoreactive zone overlapped with both the TAG‐1‐ and NB‐3‐immunoreactive zones. NB‐3‐positive puncta overlapped with vesicular glutamate transporter 1, a presynaptic marker and were apposed close to metabotropic glutamate receptor 1A, a postsynaptic marker, indicating that NB‐3 is localized presynaptically at glutamatergic synapses between parallel fibers and Purkinje cells. In NB‐3 knockout mice, L1 immunoreactive signals were increased in the IGL at postnatal day (P) 5, suggesting the increase in the number of immature granule cells of the IGL. In addition, the density of parallel fiber synaptic terminals was reduced in NB‐3 knockout mice relative to wild‐type mice at P5 to P10. In parallel with these findings, caspase‐dependent cell death was significantly increased in the NB‐ 3‐deficient cerebellum at P15. Collectively, our results indicate that NB‐3 deficiency affects synapse formation during postnatal cerebellar development. © 2009 Wiley Periodicals, Inc. Develop Neurobiol, 2009     

Cerebellar granule cells show age‐dependent migratory differences in vitro

Developmental differences between cerebellar granule cells during their migratory period were revealed using dissociated granule cell cultures isolated from 4, 7, or 10 days old (P4, P7, P10) mice. Under all culture conditions, the great majority of cultivated cell populations consisted of those granule cells that had not reach their final destination in the internal granule cell layer (IGL) by the age of isolation. In vitro morphological development and the expression of migratory markers (TAG‐1, astrotactin, or EphB2) showed similar characteristics between the cultures. The migration of 1008 granule cells isolated from P4, P7, and P10 cerebella and cultivated under identical conditions were analyzed using statistical methods. In vitro time‐lapse videomicroscopy revealed that P4 cells possessed the fastest migratory speed while P10 granule cells retained their migratory activity for the longest time in culture. Cultures obtained from younger postnatal ages showed more random migratory trajectories than P10 cultures. Our observations indicate that despite similar morphological and molecular properties, migratory differences exist in granule cell cultures isolated from different postnatal ages. Therefore, the age of investigation can substantially influence experimental results on the regulation of cell migration. © 2005 Wiley Periodicals, Inc. J Neurobiol, 2005     

Spatiotemporal expression and functional implication of CXCL14 in the developing mice cerebellum

Cerebellar granule neurons migrate from the external granule cell layer (EGL) to the internal granule cell layer (IGL) during postnatal morphogenesis. This migration process through 4 different layers is a complex mechanism which is highly regulated by many secreted proteins. Although chemokines are well-known peptides that trigger cell migration, but with the exception of CXCL12, which is responsible for prenatal EGL formation, their functions have not been thoroughly studied in granule cell migration. In the present study, we examined cerebellar CXCL14 expression in neonatal and adult mice. CXCL14 mRNA was expressed at high levels in adult mouse cerebellum, but the protein was not detected. Nevertheless, Western blotting analysis revealed transient expression of CXCL14 in the cerebellum in early postnatal days (P1, P8), prior to the completion of granule cell migration. Looking at the distribution of CXCL14 by immunohistochemistry revealed a strong immune reactivity at the level of the Purkinje cell layer and molecular layer which was absent in the adult cerebellum. In functional assays, CXCL14 stimulated transwell migration of cultured granule cells and enhanced the spreading rate of neurons from EGL microexplants. Taken together, these results revealed the transient expression of CXCL14 by Purkinje cells in the developing cerebellum and demonstrate the ability of the chemokine to stimulate granule cell migration, suggesting that it must be involved in the postnatal maturation of the cerebellum.     

Cardiotoxin III suppresses hepatocyte growth factor–stimulated migration and invasion of MDA‐MB‐231 cells

The hepatocyte growth factor (HGF)/c‐Met signalling pathway is deregulated in most cancers and associated with a poor prognosis in breast cancer. Cardiotoxin III (CTX III), a basic polypeptide isolated from Naja naja atra venom, has been shown to exhibit anticancer activity. In this study, we use HGF as an invasive inducer to investigate the effect of CTX III on MDA‐MB‐231 cells. When cells were treated with non‐toxic doses of CTX III, CTX III inhibited the HGF‐promoted cell migration and invasion. CTX III significantly suppressed the HGF‐induced c‐Met phosphorylation and downstream activation of phosphatidylinositol 3‐kinase (PI3k)/Akt and extracellular signal‐regulated kinase (ERK) 1/2. Additionally, CTX III similar to wortmannin (a PI3K inhibitor) and U0126 (an upstream kinase regulating ERK1/2 inhibitor) attenuated cell migration and invasion induced by HGF. This effect was paralleled by a significant reduction in phosphorylation of IκBα kinase and IκBα and nuclear translocation of nuclear factor κB (NF‐κB) as well as a reduction of matrix metalloproteinase‐9 (MMP‐9) activity. Furthermore, the c‐Met inhibitor PHA665752 inhibited HGF‐induced MMP‐9 expression, cell migration and invasion, as well as the activation of ERK1/2 and PI3K/Akt, suggesting that ERK1/2 and PI3K/Akt activation occurs downstream of c‐Met activation. Taken together, these findings suggest that CTX III inhibits the HGF‐induced invasion and migration of MDA‐MB‐231 cells via HGF/c‐Met‐dependent PI3K/Akt, ERK1/2 and NF‐κB signalling pathways, leading to the downregulation of MMP‐9 expression. Copyright © 2014 John Wiley & Sons, Ltd.     

Differential expression of T‐type calcium channels in P/Q‐type calcium channel mutant mice with ataxia and absence epilepsy

Mutations in P/Q‐type calcium channels generate common phenotypes in mice and humans, which are characterized by ataxia, paroxysmal dyskinesia, and absence seizures. Subsequent functional changes of T‐type calcium channels in thalamus are observed in P/Q‐type calcium channel mutant mice and these changes play important roles in generation of absence seizures. However, the changes in T‐type calcium channel function and/or expression in the cerebellum, which may be related to movement disorders, are still unknown. The leaner mouse exhibits severe ataxia, paroxysmal dyskinesia, and absence epilepsy due to a P/Q‐type calcium channel mutation. We investigated changes in T‐type calcium channel expression in the leaner mouse thalamus and cerebellum using quantitative real‐time polymerase chain reaction (qRT‐PCR) and quantitative in situ hybridization histochemistry (ISHH). qRT‐PCR analysis showed no change in T‐type calcium channel α1G subunit (Cav3.1) expression in the leaner thalamus, but a significant decrease in α1G expression in the whole leaner mouse cerebellum. Interestingly, quantitative ISHH revealed differential changes in α1G expression in the leaner cerebellum, where the granule cell layer showed decreased α1G expression while Purkinje cells showed increased α1G expression. To confirm these observations, the granule cell layer and the Purkinje cell layer were laser capture microdissected separately, then analyzed with qRT‐PCR. Similar to the observation obtained by ISHH, the leaner granule cell layer showed decreased α1G expression and the leaner Purkinje cell layer showed increased α1G expression. These results suggest that differential expression of T‐type calcium channels in the leaner cerebellum may be involved in the observed movement disorders. © 2004 Wiley Periodicals, Inc. J Neurobiol, 2005     

Transgenic mice expressing F3/contactin from the TAG-1 promoter exhibit developmentally regulated changes in the differentiation of cerebellar neurons

F3/contactin (CNTN1) and TAG-1 (CNTN2) are closely related axonal glycoproteins that are differentially regulated during development. In the cerebellar cortex TAG-1 is expressed first as granule cell progenitors differentiate in the premigratory zone of the external germinal layer. However, as these cells begin radial migration, TAG-1 is replaced by F3/contactin. To address the significance of this differential regulation, we have generated transgenic mice in which F3/contactin expression is driven by TAG-1 gene regulatory sequences, which results in premature expression of F3/contactin in granule cells. These animals (TAG/F3 mice) display a developmentally regulated cerebellar phenotype in which the size of the cerebellum is markedly reduced during the first two postnatal weeks but subsequently recovers. This is due in part to a reduction in the number of granule cells, most evident in the external germinal layer at postnatal day 3 and in the inner granular layer between postnatal days 8 and 11. The reduction in granule cell number is accompanied by a decrease in precursor granule cell proliferation at postnatal day 3, followed by an increase in the number of cycling cells at postnatal day 8. In the same developmental window the size of the molecular layer is markedly reduced and Purkinje cell dendrites fail to elaborate normally. These data are consistent with a model in which deployment of F3/contactin on granule cells affects proliferation and differentiation of these neurons as well as the differentiation of their synaptic partners, the Purkinje cells. Together, these findings indicate that precise spatio-temporal regulation of TAG-1 and F3/contactin expression is critical for normal cerebellar morphogenesis.     

Cdk5 activity is required for Purkinje cell dendritic growth in cell‐autonomous and non‐cell‐autonomous manners

Cyclin‐dependent kinase 5 (Cdk5) is recognized as a unique member among other Cdks due to its versatile roles in many biochemical processes in the nervous system. The proper development of neuronal dendrites is required for the formation of complex neural networks providing the physiological basis of various neuronal functions. We previously reported that sparse dendrites were observed on cultured Cdk5‐null Purkinje cells and Purkinje cells in Wnt1^cre‐mediated Cdk5 conditional knockout (KO) mice. In the present study, we generated L7^cre‐mediated p35; p39 double KO (L7^cre‐p35^f/f; p39^–/–) mice whose Cdk5 activity was eliminated specifically in Purkinje cells of the developing cerebellum. Consequently, these mice exhibited defective Purkinje cell migration, motor coordination deficiency and a Purkinje dendritic abnormality similar to what we have observed before, suggesting that dendritic growth of Purkinje cells was cell‐autonomous in vivo . We found that mixed and overlay cultures of WT cerebellar cells rescued the dendritic deficits in Cdk5‐null Purkinje cells, however, indicating that Purkinje cell dendritic development was also supported by non‐cell‐autonomous factors. We then again rescued these abnormalities in vitro by applying exogenous brain‐derived neurotrophic factor (BDNF). Based on the results from culture experiments, we attempted to rescue the developmental defects of Purkinje cells in L7^cre‐p35^f/f; p39^–/– mice by using a TrkB agonist. We observed partial rescue of morphological defects of dendritic structures of Purkinje cells. These results suggest that Cdk5 activity is required for Purkinje cell dendritic growth in cell‐autonomous and non‐cell‐autonomous manners. © 2017 Wiley Periodicals, Inc. Develop Neurobiol 77: 1175–1187, 2017     

The calcium‐sensing receptor and integrins modulate cerebellar granule cell precursor differentiation and migration

In the developing cerebellum granule cell precursors (GCPs) proliferate in the external granule cell layer before differentiating and migrating to the inner granule cell layer. Aberrant GCP proliferation leads to medulloblastoma, the most prevalent form of childhood brain cancer. Here, we demonstrate that the calcium‐sensing receptor (CaSR), a homodimeric G‐protein coupled receptor, functions in conjunction with cell adhesion proteins, the integrins, to enhance GCP migration and cell homing by promoting GCP differentiation. During the second postnatal week a robust peak in CaSR expression was observed in GCPs; reciprocal immunoprecipitation experiments conducted during this period established that the CaSR and β1 integrins are present together in a macromolecular protein complex. Analysis of cell‐surface proteins demonstrated that activation of the CaSR by positive allosteric modulators promoted plasma membrane expression of β1 integrins via ERK2 and AKT phosphorylation and resulted in increased GCP migration toward an extracellular matrix protein. The results of in vivo experiments whereby CaSR modulators were injected i.c.v. revealed that CaSR activation promoted radial migration of GCPs by enhancing GCP differentiation, and conversely, a CaSR inhibitor disrupted GCP differentiation and promoted GCP proliferation. Our results demonstrate that an ion‐sensing G‐protein coupled receptor acts to promote neuronal differentiation and homing during cerebellar maturation. These findings together with those of others also suggest that CaSR/integrin complexes act to transduce extracellular calcium signals into cellular movement, and may function in this capacity as a universal cell migration/homing complex in the developing brain. © 2015 Wiley Periodicals, Inc. Develop Neurobiol 76: 375–389, 2016     

Deficits of olfactory interneurons in polysialyltransferase‐ and NCAM‐deficient mice

The neurogenic niche of the anterior subventricular zone (SVZ) persistently generates neuroblasts, which migrate along the rostral migratory stream (RMS) into the olfactory bulb (OB), where they differentiate into granule and periglomerular cells. Loss of the neural cell adhesion molecule NCAM or its post‐translational modification polysialic acid (polySia) impairs migration causing accumulations of cells in the proximal RMS and decreased OB volume. Polysialylation of NCAM is implemented by two polysialyltransferases, ST8SIA2 and ST8SIA4, with overlapping functions. Here, we used mice with Ncam1 and polysialyltransferase deletions to analyze how partial or complete loss of polySia synthesis or a combined loss of polySia and NCAM affects the RMS and the interneuron composition in the OB. Numerous calretinin (CR)‐positive cells were detected dispersed around the RMS in Ncam1 knockout, St8sia2, St8sia4 double‐knockout, and St8sia2, St8sia4, Ncam1 triple‐knockout mice, as well as in St8sia2 ^?/? but not in St8sia4 ^?/? mice. These changes were not reflected by reductions of CR‐positive cells in the granule or glomerular layer of the OB. Instead, calbindin‐positive periglomerular interneurons were strongly reduced in all polySia‐NCAM negative mice and slightly attenuated in St8sia2 ^?/? as well as in the St8sia4 ^?/? mice, which were devoid of ectopic CR‐positive cells along the RMS. Consistent with the early developmental generation of calbindin‐ as compared with CR‐positive OB interneurons, this phenotype was fully developed at postnatal day 5. Together, these results demonstrate that the early development of calbindin‐positive periglomerular interneurons depends on the presentation of polySia on NCAM and requires the activity of both polysialyltransferases. © 2015 Wiley Periodicals, Inc. Develop Neurobiol 76: 421–433, 2016     

MMP‐2 and MMP‐13 affect vasculogenic mimicry formation in large cell lung cancer

Matrix metalloproteinases (MMPs) have critical functions in tumour vasculogenic mimicry (VM). This study explored the mechanisms underlying MMP‐13 and MMP‐2 regulation of tumour VM formation in large cell lung cancer (LCLC). In our study, laminin5 (Ln‐5) fragments cleaved by MMP‐2 promoted tubular structure formation by the LCLC cell lines H460 and H661 in three‐dimensional (3D) cultures. Transient up‐regulation of MMP‐13 or treatment with recombinant MMP‐13 protein abrogated tubular structure formation of H460 cells in 3D culture. Treated cells with Ln‐5 fragments cleaved by MMP‐2 stimulated EGFR and F‐actin expression. Ln‐5 fragments cleaved by MMP‐13 decreased EGFR/F‐actin expression and disrupted VM formation. MMP‐13 expression was negatively correlated with VM, Ln‐5 and EGFR in LCLC tissues and xenograft. In vivo experiments revealed that VM was decreased when the number of endothelium‐dependent vessels (EDVs) increased during xenograft tumour growth, whereas MMP‐13 expression was progressively increased. In conclusion, MMP‐2 promoted and MMP‐13 disrupted VM formation in LCLC by cleaving Ln‐5 to influence EGFR signal activation. MMP‐13 may regulate VM and EDV formation.     

c‐Cbl regulates glioma invasion through matrix metalloproteinase 2

c‐Cbl, a multifunctional adaptor and an E3 ubiquitin ligase, plays a role in such cytoskeleton‐mediated events as cell adhesion and migration. Invasiveness of human glioma is dependent on cell adhesion, migration, and degradation of extracellular matrix (ECM). However, the function of c‐Cbl in glioma invasion has never been investigated. We report here, for the first time, that c‐Cbl plays a positive role in the invasion of ECM by SNB19 glioma cells. RNAi‐mediated depletion of c‐Cbl decreases SNB19 cell invasion and expression of matrix metalloproteinase 2 (MMP2). Consistent with these findings, SNB19 cells expressing wild‐type, but not mutant c‐Cbl show increased invasion and MMP2 expression. We demonstrate that the observed role of c‐Cbl in invasion of SNB19 cells is not mediated by the previously shown effects of c‐Cbl on cell adhesion and migration or on EGFR signaling. Together, our results suggest that c‐Cbl promotes glioma invasion through up‐regulation of MMP2. J. Cell. Biochem. 111: 1169–1178, 2010. © 2010 Wiley‐Liss, Inc.     

Potential regulatory network in the PSG10P/miR‐19a‐3p/IL1RAP pathway is possibly involved in preeclampsia pathogenesis

Preeclampsia (PE), a pregnancy‐specific disorder, is a leading cause of perinatal maternal‐fetal mortality and morbidity. Impaired cell migration and invasion of trophoblastic cells and an imbalanced systemic maternal inflammatory response have been proposed as potential mechanisms of PE pathogenesis. Comparative analysis between PE placentas and normal placentas profiled differentially expressed miRNAs, lncRNAs, and mRNAs, including miR‐19a‐3p (miRNA), PSG10P (lncRNA), and IL1RAP (mRNA). This study was conducted to investigate their potential roles in PE pathogenesis. The expression of miR‐19a‐3p, PSG10P, and IL1RAP was examined in PE and normal placentas using RT‐qPCR. An in vitro experiment was performed in human trophoblast HET8/SVneo and TEV‐1 cells cultured in normoxic and hypoxic conditions. MiR‐19a‐3p targets were identified using Targetscan, miRanda, and PicTar analysis as well as luciferase reporter assays. The mouse model of PE was conducted using sFlt‐1 for in vivo tests. Lower levels of miR‐19a‐3p, but higher levels of PSG10P and IL1RAP were observed in PE placentas and the trophoblast cells in hypoxia. Luciferase reporter assays confirmed that PSG10P and IL1RAP were both direct targets of miR‐19a‐3p. Exposure to hypoxia inhibited cell viability, migration, and invasion of HET8/SVneo and TEV‐1 cells. Knocking out PSG10P and IL1RAP or overexpressing miR‐19a‐3p rescued the inhibition caused by hypoxia. In vivo experiments showed that IL1RAP promoted the expression of caspase‐3, a key apoptosis enzyme, but inhibited MMP9, which is responsible for degrading the extracellular matrix, suggesting a significant role of IL1RAP in cell proliferation, migration, and invasion. miR‐19a‐3p, PSG10P, and IL1RAP were all found to be involved in PE pathogenesis. With a common targeting region in their sequences, a regulatory network in the PSG10P/miR‐19a‐3p/IL1RAP pathway may contribute to PE pathogenesis during pregnancy.     

Role of GPER on proliferation,migration and invasion in ligand‐independent manner in human ovarian cancer cell line SKOV3

G protein‐coupled estrogen receptor (GPER) is identified as a critical estrogen receptor, in addition to the classical estrogen receptors ERα and ERβ. In ERα‐negative ovarian cancer cells, our previous studies have found that estrogen stimulated cell proliferation and metastasis via GPER. However, the ligand‐independent function of GPER in ovarian cancer cells is still not clear. Herein, we describe that GPER has a co‐expression with ERα and ERβ, which are first determined in SKOV3 ovarian cancer cell line. In the absence of estrogen, GPER depletion by specific siRNA inhibits the proliferation, migration and invasion of SKOV3 cells. Whereas abrogation of ERα or ERβ by specific antagonist MPP and PHTPP has the opposite effects for stimulation of cell growth. Markedly, GPER knockdown attenuates MPP or PHTPP‐induced cell proliferation, migration and invasion. Furthermore, GPER modulates protein expression of the cell cycle critical components, c‐fos and cyclin D1 and factors for cancer cell invasion and metastasis, matrix metalloproteinase 2 (MMP‐2) and MMP‐9. These findings establish that GPER ligand‐independently stimulates the proliferation, migration and invasion of SKOV3 cells. Knockdown of GPER attenuates the progression of ovarian cancer that caused by functional loss of ERα or ERβ. Targeting GPER provides new aspect as a potential therapeutic strategy in ovarian cancer. Copyright © 2015 John Wiley & Sons, Ltd.     

Down‐regulating Myoferlin inhibits the vasculogenic mimicry of melanoma via decreasing MMP‐2 and inducing mesenchymal‐to‐epithelial transition

Vasculogenic mimicry (VM) constitutes a novel approach for tumour blood supply and contributes to tumour metastasis and poor prognosis in patients with melanoma. Myoferlin (MYOF), a type II membrane protein involved in membrane regeneration and repair, is elevated in several malignant tumours, especially in advanced melanomas. This study aims to investigate the role and mechanism of MYOF in the regulation of VM. VM structures were found in 14 of 52 tested melanoma samples, and high MYOF expression correlated with VM structures. According to Kaplan–Meier survival curves, VM channels and elevated MYOF expression both correlated with poor prognosis in melanoma patients. Down‐regulation of MYOF by siRNA severely impaired the capability of A375 cells to form VM structures in vitro. Further studies demonstrated MYOF knockdown inhibited cell migration and invasion, which is required for VM formation, via decreasing MMP‐2 expression as evidenced by Western blotting, RT‐RCP and ELISA results. SB‐3CT, a specific inhibitor of MMP‐2, showed similar inhibiting effects with siMYOF, further supporting that MYOF down‐regulation inhibits MMP‐2 expression to affect VM formation. Moreover, MYOF knockdown suppress VM formation by A375 cells by inducing mesenchymal‐to‐epithelial transition (MET). After down‐regulating MYOF, focal adhesions were enlarged and A375 cells developed into a clear epithelial morphology. Such cells acquired the expression of E‐cadherin at adherens junctions along with a loss of mesenchymal markers, such as Vimentin and Twist1. In conclusion, MYOF plays an important role in VM and knockdown of MYOF suppresses VM formation via decreasing MMP‐2 and inducing MET in A375 melanoma cells.     

The lncRNA TP73‐AS1 promotes ovarian cancer cell proliferation and metastasis via modulation of MMP2 and MMP9

Ovarian cancer is one of the most common gynecologic malignancy with poor prognosis. Recently, long noncoding RNAs (lncRNAs) have been identified as key regulators in cancer development. The current study investigated the role of lncRNA P73 antisense RNA 1T (TP73‐AS1) in ovarian cancer. Quantitative real‐time polymerase chain reaction determined the expression levels of TP‐73AS1, matrix metallopeptidases (MMPs) messenger RNA. Cell proliferative ability, cell invasion, and migration were CCK‐8 and colony formation, and transwell invasion and migration assays, respectively. The protein levels of matrix metallopeptidase 2 (MMP2) and MMP9 were measured by Western blot. TP73‐AS1 was upregulated in the ovarian cancer tissues and ovarian cancer cells, and upregulation of TP73‐AS1 was associated with poor prognosis. Knockdown of TP73‐AS1 significantly suppressed cell proliferation, invasion, and migration of SKOV3 cells, and overexpression of TP73‐AS1 promoted cell proliferation, invasion, and migration of OVCA429 cells. In addition, knockdown of TP73‐AS1 suppressed the in vivo tumor growth. Tumor metastasis RT² profiler polymerase chain reaction array showed that MMP2 and MMP9 was significantly upregulated by TP73‐AS1 overexpression in ovarian cancer cells. TP73‐AS1 overexpression enhanced the expression of MMP2 and MMP9 in ovarian cancer cells. Knockdown of MMP2 and MMP9 attenuated the effects of TP73‐AS1 overexpression on cell invasion and migration. The clinical data showed that MMP2 and MMP9 were upregulated and positively correlated with TP73‐AS1 expression in ovarian cancer tissues. Collectively, our results demonstrated the oncogenic role of TP73‐AS1 in ovarian cancer, and targeting TP73‐AS1 may represent a novel approach in battling against ovarian cancer.     

Different regulation of Purkinje cell dendritic development in cerebellar slice cultures by protein kinase Cα and ‐β

Activity of protein kinase C (PKC), and in particular the PKCγ‐isoform, has been shown to strongly affect and regulate Purkinje cell dendritic development, suggesting an important role for PKC in activity‐dependent Purkinje cell maturation. In this study we have analyzed the role of two additional Ca²⁺‐dependent PKC isoforms, PKCα and ‐β, in Purkinje cell survival and dendritic morphology in slice cultures using mice deficient in the respective enzymes. Pharmacological PKC activation strongly reduced basal Purkinje cell dendritic growth in wild‐type mice whereas PKC inhibition promoted branching. Purkinje cells from mice deficient in PKCβ, which is expressed in two splice forms by granule but not Purkinje cells, did not yield measurable morphological differences compared to respective wild‐type cells under either experimental condition. In contrast, Purkinje cell dendrites in cultures from PKCα‐deficient mice were clearly protected from the negative effects on dendritic growth of pharmacological PKC activation and showed an increased branching response to PKC inhibition as compared to wild‐type cells. Together with our previous work on the role of PKCγ, these data support a model predicting that normal Purkinje cell dendritic growth is mainly regulated by the PKCγ‐isoform, which is highly activated by developmental processes. The PKCα isoform in this model forms a reserve pool, which only becomes activated upon strong stimulation and then contributes to the limitation of dendritic growth. The PKCβ isoform appears to not be involved in the signaling cascades regulating Purkinje cell dendritic maturation in cerebellar slice cultures. © 2003 Wiley Periodicals, Inc. J Neurobiol 57: 95–109, 2003     

Aromatic‐turmerone attenuates invasion and expression of MMP‐9 and COX‐2 through inhibition of NF‐κB activation in TPA‐induced breast cancer cells

Recent evidence suggests that breast cancer is one of the most common forms of malignancy in females, and metastasis from the primary cancer site is the main cause of death. Aromatic (ar)‐turmerone is present in Curcuma longa and is a common remedy and food. In the present study, we investigated the inhibitory effects of ar‐turmerone on expression and enzymatic activity levels of 12‐O‐tetradecanoylphorbol‐13‐acetate (TPA)‐induced matrix metalloproteinase (MMP)‐9 and cyclooxygenaase‐2 (COX‐2) in breast cancer cells. Our data indicated that ar‐turmerone treatment significantly inhibited enzymatic activity and expression of MMP‐9 and COX‐2 at non‐cytotoxic concentrations. However, the expression of tissue inhibitor of metalloproteinase (TIMP)‐1, TIMP‐2, MMP‐2, and COX‐1 did not change upon ar‐turmerone treatment. We found that ar‐turmerone inhibited the activation of NF‐κB, whereas it did not affect AP‐1 activation. Moreover, The ChIP assay revealed that in vivo binding activities of NF‐κB to the MMP‐9 and COX‐2 promoter were significantly inhibited by ar‐turmerone. Our data showed that ar‐turmerone reduced the phosphorylation of PI3K/Akt and ERK1/2 signaling, whereas it did not affect phosphorylation of JNK or p38 MAPK. Thus, transfection of breast cancer cells with PI3K/Akt and ERK1/2 siRNAs significantly decreased TPA‐induced MMP‐9 and COX‐2 expression. These results suggest that ar‐turmerone suppressed the TPA‐induced up‐regulation of MMP‐9 and COX‐2 expression by blocking NF‐κB, PI3K/Akt, and ERK1/2 signaling in human breast cancer cells. Furthermore, ar‐turmerone significantly inhibited TPA‐induced invasion, migration, and colony formation in human breast cancer cells. J. Cell. Biochem. 113: 3653–3662, 2012. © 2012 Wiley Periodicals, Inc.