The Somatostatin receptor subtypes SSTR2 and SSTR5 mediate the inhibition of cell proliferation

Buscail, Louis; Esteve, J; Saint-Laurent, Nathalie; Bertrand, Viviane; Chastre, Eric; Gespach, Christian; Reisine, T; O'Carroll, A-M; Kalthof, H.; Bell, G. I.; Schally, A.V.; Vaysse, Nicole; Susini, C.

doi:10.1016/0016-5085(95)28124-x

Cited by 21 publications

(72 citation statements)

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“…The prominence of the SSTR2 subtype in neuroblastoma tumors is in agreement with other studies [25,26]. Interestingly both the SSTR2 and SSTR5 subtypes have been demonstrated to inhibit cell proliferation, although by distinct intracellular mechanisms [27].…”

Section: Discussionsupporting

confidence: 91%

Coexistence of somatostatin receptor subtypes in the human neuroblastoma cell line LA‐N‐2

Nilsson

Folkesson

1997

FEBS Letters

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Five distinct human somatostatin receptor subtypes have recently been cloned and characterized. Previous studies have suggested that these receptor subtypes might display coexistent localization, based on in situ hybridization or immunoblockage experiments. Here we provide evidence for coexistence of somatostatin receptor subtypes 2 and 5 in the human neuroblastoma cell line LA-N-2, using a combined approach with RT-PCR and receptor binding studies with somatostatin analogues. Somatostatin receptor subtypes simultaneously localized to a single cell might serve distinct functions in terms of targeting to different intraneuronal compartments or subtype specificity against so far unidentified somatostatinrelated peptides.

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Section: Discussionsupporting

confidence: 91%

Coexistence of somatostatin receptor subtypes in the human neuroblastoma cell line LA‐N‐2

Nilsson

Folkesson

1997

FEBS Letters

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“…Cell Culture and Growth Assay-CHO cells and its derivatives were cultured in ␣MEM containing 10% FCS and G418 (200 g/ml) as described previously (14). For cell treatment, cells were plated in 100-mm dishes (10 6 cells/dish) in ␣MEM containing 10% FCS, and after an overnight attachment phase, cells were cultured for 24 h, washed, and cultured overnight in serum-free ␣MEM.…”

Section: Materials-smsmentioning

confidence: 99%

“…Binding Studies- [Tyr 11 ]somatostatin was radioiodinated and purified by reverse phase-high performance liquid chromatography as described previously (14). Cells were grown in 75-cm 2 flasks for 48 h and lysed by freezing in liquid nitrogen in 50 mM Tris-HCl (pH 7.8) containing soybean trypsin inhibitor (0.3 mg/ml).…”

Section: Materials-smsmentioning

confidence: 99%

“…After thawing, the cell lyzate was centrifuged at 26,000 ϫ g for 30 min at 4°C, and the pellet was resuspended in the same buffer. Binding studies were performed on the resultant crude membranes as described previously (14). Briefly, 5 g of membrane proteins were incubated with 30 pM [ 125 I-Tyr 11 ]somatostatin at 25°C for 90 min in 50 mM Tris-HCl (pH 7.8) containing bovine serum albumin (1 mg/ml), soybean trypsin inhibitor (0.3 mg/ml), bacitracin (0.5 mg/ml), 5 mM MgSO 4 (binding buffer).…”

Section: Materials-smsmentioning

confidence: 99%

“…Although the molecular events leading to the inhibition of cell proliferation are still poorly understood, it has been shown that, after binding to somatostatin receptors, somatostatin analogues cause a rapid stimulation of a membrane proteintyrosine phosphatase (PTPase) 1 activity and dephosphorylate phosphorylated epidermal growth factor receptors (9,11,12) suggesting that a PTPase may participate in the somatostatininduced inhibition of growth factor-mediated mitogenic signal. Recently, the expression of the sst2 somatostatin receptor subtype in NIH3T3 and Chinese hamster ovary (CHO) cells led us to the demonstration of the direct involvement of sst2 in both the antiproliferative effect of somatostatin and its stimulatory effect on PTPase activity (13,14). Incubation of cells expressing sst2 with the PTPase inhibitor, vanadate, prevented both effects suggesting that a PTPase may be implicated in the negative growth signal induced by activation of sst2.…”

mentioning

confidence: 99%

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The Tyrosine Phosphatase SHP-1 Associates with the sst2 Somatostatin Receptor and Is an Essential Component of sst2-mediated Inhibitory Growth Signaling

Lopez

Estève

Buscail

et al. 1997

Journal of Biological Chemistry

162

116

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Activation of the somatostatin receptor sst2, a member of the G i protein-coupled receptor family, results in the stimulation of a protein-tyrosine phosphatase activity involved in the sst2-mediated growth inhibitory signal. Here, we report that SHP-1, a cytoplasmic proteintyrosine phosphatase containing two Src homology 2 domains constitutively associated with sst2 as evidence by coprecipitation of SHP-1 protein with sst2, in Chinese hamster ovary cells coexpressing sst2 and SHP-1. Activation of sst2 by somatostatin resulted in a rapid dissociation of SHP-1 from sst2 accompanied by an increase of SHP-1 activity. SHP-1 was phosphorylated on tyrosine in control cells and somatostatin induced a rapid and transient dephosphorylation on tyrosine residues of the enzyme. Stimulation of SHP-1 activity by somatostatin was abolished by pertussis toxin pretreatment of cells. G i␣3 was specifically immunoprecipitated by anti-sst2 and anti-SHP-1 antibodies, and somatostatin induced a rapid dissociation of G i␣3 from sst2, suggesting that G i␣3 may be involved in the sst2⅐SHP-1 complexes. Finally, somatostatin inhibited the proliferation of cells coexpressing sst2 and SHP-1, and this effect was suppressed in cells coexpressing sst2 and the catalytic inactive SHP-1 (C453S mutant). Our data identify SHP-1 as the tyrosine phosphatase associated with sst2 and demonstrate that this enzyme may be an initial key transducer of the antimitogenic signaling mediated by sst2.

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Somatostatin inhibits PDGF‐stimulated Ras activation in human neuroblastoma cells

1999

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The main physiological role of somatostatin (SST) is the control of hormone secretion. Recently, SST has been shown to exert antiproliferative effects on some human tumors via both direct and indirect mechanisms. We have previously found that in the human neuroblastoma cell line SY5Y the SST analogue lanreotide (BIM 23014) inhibited serum-stimulated cell proliferation and MAP kinase activity. Here, we examine the effect of SST on PDGF-induced Ras activation. We found that SST suppressed PDGF-induced Ras activation in a pertussis toxin (PTx)-independent and peroxovanadate-dependent manner. Rasspecific GTPase activating protein (GAP) activities were not altered by SST treatment. On the contrary, PDGF-induced PDGF receptor phosphorylation was decreased by SST in a PTx-independent, peroxovanadate-dependent manner, likely accounting for the SST-mediated inhibition of PDGF-induced Ras activation.z 1999 Federation of European Biochemical Societies.

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The Somatostatin receptor subtypes SSTR2 and SSTR5 mediate the inhibition of cell proliferation

Cited by 21 publications

References 0 publications

Coexistence of somatostatin receptor subtypes in the human neuroblastoma cell line LA‐N‐2

Coexistence of somatostatin receptor subtypes in the human neuroblastoma cell line LA‐N‐2

The Tyrosine Phosphatase SHP-1 Associates with the sst2 Somatostatin Receptor and Is an Essential Component of sst2-mediated Inhibitory Growth Signaling

Somatostatin inhibits PDGF‐stimulated Ras activation in human neuroblastoma cells

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