| 1. |
- Ding, W Q, et al.
(författare)
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Effects of ethanol on muscarinic receptor-stimulated c-fos expression in human neuroblastoma cells
- 1997
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Ingår i: Brain Research. Molecular Brain Research. - 0169-328X. ; 46:1-2, s. 77-84
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Tidskriftsartikel (refereegranskat)abstract
- The effect of ethanol exposure on muscarinic receptor-stimulated expression of c-fos was investigated in SH-SY5Y cells. Four days of ethanol exposure enhanced carbachol-stimulated c-fos mRNA expression, analyzed with Northern blot, and Fos/AP-1 binding activity, measured with gel mobility super shift assay. Pre-incubation with muscarinic antagonists or the protein kinase C inhibitor GF109203X demonstrated that, in both control and ethanol-treated cells, carbachol-induced c-fos expression was mediated via muscarinic M1 receptors and to a large extent through protein kinase C. However, phorbol ester-induced c-fos expression was unaffected in ethanol-treated cells. Acute exposure to ethanol caused a suppression of both carbachol- and phorbol ester-stimulated c-fos expression. These results demonstrate that muscarinic receptor-stimulated gene expression is sensitive to both acute and long-term ethanol exposure.
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| 2. |
- Ding, W Q, et al.
(författare)
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Acute ethanol exposure attenuates expression of junD in human neuroblastoma cells
- 1998
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Ingår i: Neurochemistry International. - 0197-0186. ; 33:6, s. 525-530
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Tidskriftsartikel (refereegranskat)abstract
- This study describes the effects of acute ethanol exposure on the mRNA levels of c-jun,junB and junD in the human neuroblastoma SH-SY5Y cell line. An acute exposure to 100 mM ethanol did not influence the basal and phorbol ester-induced expression of c-jun and junB, whereas the basal mRNA level of junD was attenuated by 30%. This effect was dose- and time-dependent with maximal inhibition being detected 2 h after 100 mM ethanol treatment and the mRNA levels gradually returned towards normal afterwards. Ethanol also inhibited phorbol ester-induced expression of junD. The fact that ethanol did not influence degradation of the junD mRNA suggests that acute ethanol suppresses the transcription of the gene. These results indicate that acute ethanol exerts different effects on expression of Jun transcription factors, suggesting that as compared to c-jun and junB, the junD gene may be more sensitive to acute ethanol treatment in neuronal cells.
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| 3. |
- Zeidman, Ruth, et al.
(författare)
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PKCepsilon, via its regulatory domain and independently of its catalytic domain, induces neurite-like processes in neuroblastoma cells
- 1999
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Ingår i: Journal of Cell Biology. - 0021-9525. ; 145:4, s. 713-726
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Tidskriftsartikel (refereegranskat)abstract
- To investigate the role of protein kinase C (PKC) isoforms in regulation of neurite outgrowth, PKCalpha, betaII, delta, and epsilon fused to enhanced green fluorescent protein (EGFP) were transiently overexpressed in neuroblastoma cells. Overexpression of PKCepsilon-EGFP induced cell processes whereas the other isoforms did not. The effect of PKCepsilon-EGFP was not suppressed by the PKC inhibitor GF109203X. Instead, process formation was more pronounced when the regulatory domain was introduced. Overexpression of various fragments from PKCepsilon regulatory domain revealed that a region encompassing the pseudosubstrate, the two C1 domains, and parts of the V3 region were necessary and sufficient for induction of processes. By deleting the second C1 domain from this construct, a dominant-negative protein was generated which suppressed processes induced by full-length PKCepsilon and neurites induced during retinoic acid- and growth factor-induced differentiation. As with neurites in differentiated neuroblastoma cells, processes induced by the PKCepsilon- PSC1V3 protein contained alpha-tubulin, neurofilament-160, and F-actin, but the PKCepsilon-PSC1V3-induced processes lacked the synaptic markers synaptophysin and neuropeptide Y. These data suggest that PKCepsilon, through its regulatory domain, can induce immature neurite-like processes via a mechanism that appears to be of importance for neurite outgrowth during neuronal differentiation.
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| 4. |
- Gestblom, C, et al.
(författare)
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The basic helix-loop-helix transcription factor dHAND, a marker gene for the developing human sympathetic nervous system, is expressed in both high- and low-stage neuroblastomas
- 1999
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Ingår i: Laboratory Investigation. - 1530-0307 .- 0023-6837. ; 79, s. 67-
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Tidskriftsartikel (refereegranskat)abstract
- Neuroblastoma is derived from the sympathetic nervous system and might arise as a result of impaired differentiation, retaining the neuroblastic tumor cells in the cell cycle. Thus, to understand the genesis of neuroblastoma, the study of mechanisms and genes regulating normal sympathetic development is of potential interest. The basic helix-loop-helix transcription factors human achaete-scute homolog-1 (HASH-1) and deciduum, heart, autonomic nervous system, and neural crest derivatives (dHAND) are expressed in the sympathetic nervous system of embryonic mice and chicken, with undetectable postnatal expression. By in situ hybridization technique, we show that dHAND was expressed by human sympathetic neuronal and extra-adrenal chromaffin cells throughout embryonic and fetal life, and was initially expressed in immature chromaffin cells of the adrenal gland. With overt chromaffin differentiation, dHAND was down-regulated. HASH-1, in contrast, was expressed in human sympathetic cells only at the earliest embryonic ages examined (Week 6.5 to 7). All examined neuroblastoma specimens (25/25) and all cell lines (5/5) had detectable dHAND mRNA levels. HASH-1 expression in tumor specimens was more restricted, although all cell lines (5/5) were HASH-1-positive. These results show that neuroblastoma tumors have retained embryonic features, suggesting that many neuroblastomas are blocked at an early stage of normal development when HASH-1 and dHAND are expressed. dHAND also appears to be a reliable and potentially useful clinical diagnostic marker for neuroblastoma, because expression was not dependent on tumor or differentiation stages and other pediatric tumors were dHAND-negative.
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| 5. |
- Gustavsson, Lena, et al.
(författare)
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Regulation of phospholipase D activity in neuroblastoma cells
- 1996
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Ingår i: Journal of Lipid Mediators and Cell Signalling. - : Elsevier BV. - 0929-7855. ; 14:1-3, s. 229-235
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Tidskriftsartikel (refereegranskat)abstract
- The regulation of phospholipase D was studied in human neuroblastoma cells using phosphatidylethanol as a marker of the enzyme activity. Carbachol induced phospholipase D activity in SH-SY5Y cells. Muscarinic antagonists inhibited the response with potencies suggesting that muscarinic M1 receptors are responsible for the activation. In permeabilized SH-SY5Y cells, both the carbachol- and GTP gamma S-induced Peth formation was inhibited by GDP beta S, indicating that both responses are mediated via a G-protein. The protein kinase C inhibitors, bisindolylmaleimide and staurosporine significantly inhibited the carbachol-induced Peth formation whereas H7 had no effect. Thus, the cholinergic activation of phospholipase D in SH-SY5Y cells is probably mediated via a direct receptor-G-protein coupling but an involvement of protein kinase C cannot be excluded. Calmidazolium, a calmodulin antagonist, induced an increase in phosphatidylethanol formation in both SH-SY5Y and IMR-32 cells. This effect was inhibited by genistein and tyrphostin, indicating a tyrosine kinase dependent pathway for phospholipase D activation in neuroblastoma cells.
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| 6. |
- IzquierdoClaros, R.M., et al.
(författare)
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Acute effects of D-1 and D-2-receptor agonist and antagonist drugs on somatostatin binding, inhibition of adenylyl cyclase activity and accumulation of inositol 1,4,5-trisphosphate in the rat striatum
- 1997
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Ingår i: Brain Research. Molecular Brain Research. - 0169-328X. ; 47:1-2, s. 99-107
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Tidskriftsartikel (refereegranskat)abstract
- A recent study carried out by our group demonstrated that exogenous dopamine increases the somatostatin (SS) receptor–effector system in the rat striatum. The present study examined the participation of the D1- and D2-dopaminergic systems in the modulation of the rat striatal SS receptor–effector system by use of the D1-receptor agonist and antagonist SKF 38393 and SCH 23390, respectively, and the D2-receptor agonist and antagonist bromocriptine and raclopride, respectively. In view of the rapid onset of dopamine action, the effect of dopaminergic agents on the SS mechanism of action were studied 3 h after their administration. SKF 38393 (4 mg/kg i.p.) or bromocriptine (2 mg/kg i.p.) administered to male Wistar rats increased the number of 125I-Tyr3-SMS receptors in the striatum (52 and 30%, respectively) without changing the affinity constant. The effect of SKF 38393 on 125I-Tyr3-SMS binding was antagonized by the D1-specific antagonist SCH 23390 (0.25 mg/kg i.p.) whereas the effect of bromocriptine was abolished by the D2-specific antagonist raclopride (5 mg/kg i.p.). No change in binding was produced when SKF 38393 or bromocriptine were added directly to the incubation medium. The acute systemic administration of SCH 23390 or raclopride alone had no effect on the binding of 125I-Tyr3-SMS to its receptors. The increase of the number of 125I-Tyr3-SMS receptor induced by SKF 38393 or bromocriptine was accompanied by an increase in the capacity of SMS 201-995 to inhibit basal and forskolin (FK)-stimulated adenylyl cyclase (AC) activity when compared to the control groups. In addition, the effect of SMS 201-995 on the mass accumulation of inositol 1,4,5-trisphosphate (IP3) was investigated. SKF 38393 as well as bromocriptine increased the capacity of SMS 201-995 to accumulate IP3 in the rat striatum although this effect was only statistically significant in the case of SKF 38393. These results suggest that the activation of D1 and D2 receptors increases the activity of the SS receptor–effector system, the effect being greater in the case of D1 receptors. These findings are consistent with a functional interaction between dopamine and SS in the rat striatum.
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| 7. |
- Zeidman, Ruth, et al.
(författare)
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Novel and classical protein kinase C isoforms have different functions in proliferation, survival and differentiation of neuroblastoma cells
- 1999
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Ingår i: International Journal of Cancer. - 0020-7136. ; 81:3, s. 494-501
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Tidskriftsartikel (refereegranskat)abstract
- To elucidate the possibility of utilizing protein kinase C (PKC) isoforms as target genes in neuroblastoma therapy, 5 neuroblastoma cell lines and neuroblastoma tumor specimens were examined for PKC isoform expression pattern and the cell lines were analyzed for sensitivity to PKC inhibition. All cell lines [IMR-32, LAN-2, LAN-5, SH-SY5Y and SK-N-BE(2)] expressed alpha, betaII, delta and epsilon isoforms of PKC, while no PKCeta or theta protein was detected in any cell line. PKCgamma was found only in LAN-2 cells. PKCalpha, betaII and delta were detected in 5 neuroblastoma tumors and PKCepsilon in 4 out of 5 tumors. Exposure to the PKC inhibitors GF109203X, Go 6976 or Go 6983 caused a decrease whereas activation of PKC with 12-O-tetradecanoyl phorbol 13-acetate caused an increase in the number of neuroblastoma cells. The effect of Go 6976 was due to both inhibited proliferation and to increased apoptosis. While GF109203X suppressed neurite outgrowth induced by a growth factor combination, Go 6976 potentiated neurite outgrowth. Our data suggest a role for classical PKC isoforms in neuroblastoma growth and survival and for novel isoforms in neurite outgrowth.
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