Temporal relationship between inositol polyphosphate formation and increases in cytosolic Ca2+ in quiescent 3T3 cells stimulated by platelet-derived growth factor, bombesin and vasopressin.

Nånberg, Eewa

doi:10.1002/j.1460-2075.1988.tb03128.x

Cited by 123 publications

(48 citation statements)

References 47 publications

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“…One is from bombesin or thrombin, and the other is from PDGF. The former is disrupted by pertussis toxin, which suggests the involvement of a G protein, and the latter is insensitive to the toxin (26)(27)(28)(29)(30)(31). Our results presented in Fig.…”

Section: Discussionsupporting

confidence: 49%

Platelet-derived growth factor stimulates formation of active p21ras.GTP complex in Swiss mouse 3T3 cells.

Satoh

Endo

Nakafuku

et al. 1990

Proc. Natl. Acad. Sci. U.S.A.

256

139

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The ras gene product (p21) is a GTP-binding protein and is thought to play an important role in signal transduction of growth and differentiation in many types of mammalian cells. The p2FGTP complex is an active conformation, as described previously for polypeptide chain elongation factors (EF-Tu and EF-G) and heterotrimeric GTPbinding proteins (G proteins). In the study reported here, we measured the amounts ofp21-bound guanine nucleotides under various conditions in the G54 cell line, a derivative of Swiss 3T3 cells that overexpresses normal c-Ha-ras. More p21GTP complexes were present in growing cells than in quiescent cells. When quiescent cells were stimulated with fetal bovine serum to promote DNA synthesis, p2l-GTP increased --fold. Among a number of purified growth factors, platelet-derived growth factor enhanced the formation of p2lFGTP, whereas the combination of bombesin and insulin, which also induces DNA synthesis, did not. These results strongly suggest that p21 is a transducer of the growth signal from the platelet-derived growth factor receptor in Swiss 3T3 cells and that the signal is transmitted through a p2FGTP complex.The ras protooncogene product (p21) is a GTP-binding protein involved in the transduction of signals controlling cellular proliferation and differentiation (1). The activity of a GTPbinding protein is regulated by the bound guanine nucleotide, GDP or GTP. The protein-GDP complex is an inactive conformation and nucleotide exchange from GDP to GTP activates the protein. The active protein-GTP complex specifically interacts with an effector molecule, which transduces the signal downstream. Hydrolysis of the bound GTP to GDP and Pi converts the protein-guanine nucleotide complex to an inactive form. Thus, the activity of a GTPbinding protein is regulated at two steps-i.e., the GDP/GTP

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Section: Discussionsupporting

confidence: 49%

Platelet-derived growth factor stimulates formation of active p21ras.GTP complex in Swiss mouse 3T3 cells.

Satoh

Endo

Nakafuku

et al. 1990

Proc. Natl. Acad. Sci. U.S.A.

256

139

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“…PLC␤ produces inositol 1,4,5-triphosphate which mobilizes Ca 2ϩ from internal VOL. 21,2001 EFFECTS OF NEUROPEPTIDES ON PROSTATE CANCER CELL LINEstores and diacylglycerol which in turn, activates PKC (23,35,59). A recent study by Buhl et al showed that G␣12 is also activated by bombesin (18).…”

Section: Discussionmentioning

confidence: 99%

Neuropeptide-Induced Androgen Independence in Prostate Cancer Cells: Roles of Nonreceptor Tyrosine Kinases Etk/Bmx, Src, and Focal Adhesion Kinase

Lee

Guan

Qiu

et al. 2001

Molecular and Cellular Biology

163

152

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The bombesin/gastrin-releasing peptide (GRP) family of neuropeptides has been implicated in various in vitro and in vivo models of human malignancies including prostate cancers. It was previously shown that bombesin and/or neurotensin (NT) acts as a survival and migratory factor(s) for androgen-independent prostate cancers. However, a role in the transition from an androgen-dependent to -refractory state has not been addressed. In this study, we investigate the biological effects and signal pathways of bombesin and NT on LNCaP, a prostate cancer cell line which requires androgen for growth. We show that both neurotrophic factors can induce LNCaP growth in the absence of androgen. Concurrent transactivation of reporter genes driven by the prostate-specific antigen promoter or a promoter carrying an androgen-responsive element (ARE) indicate that growth stimulation is accompanied by androgen receptor (AR) activation. Furthermore, neurotrophic factor-induced gene activation was also present in PC3 cells transfected with the AR but not in the parental line which lacks the AR. Given that bombesin does not directly bind to the AR and is known to engage a G-protein-coupled receptor, we investigated downstream signaling events that could possibly interact with the AR pathway. We found that three nonreceptor tyrosine kinases, focal adhesion kinase (

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“…Excess Fura-2/AM was removed by washing with HBSS. Intracellular calcium measurements were carried out using 2 ml of cell suspension at 37 Њ C within 2 h of loading as described earlier (27,28). Briefly, the fluorescence was monitored in a luminescence spectrometer (LS-5; Perkin-Elmer, Norwalk, CT) with an excitation wavelength of 336 nm and an emission wavelength of 510 nm using leptin (1 nmol и liter .…”

Section: Methodsmentioning

confidence: 99%

Leptin rapidly suppresses insulin release from insulinoma cells, rat and human islets and, in vivo, in mice.

Kulkarni¹,

Wang²,

Wang³

et al. 1997

J. Clin. Invest.

284

216

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Obesity is associated with diabetes, and leptin is known to be elevated in obesity. To investigate whether leptin has a direct effect on insulin secretion, isolated rat and human islets and cultured insulinoma cells were studied. In all cases, mouse leptin inhibited insulin secretion at concentrations within the plasma range reported in humans. Insulin mRNA expression was also suppressed in the cultured cells and rat islets. The long form of the leptin receptor (OB-Rb) mRNA was present in the islets and insulinoma cell lines. To determine the significance of these findings in vivo, normal fed mice were injected with two doses of leptin. A significant decrease in plasma insulin and associated rise in glucose concentration were observed. Fasted normal and leptin receptor-deficient db/db mice showed no response to leptin. A dose of leptin, which mimicked that found in normal mice, was administered to leptin-deficient, hyperinsulinemic ob/ob mice. This caused a marked lowering of plasma insulin concentration and a doubling of plasma glucose. Thus, leptin has a powerful acute inhibitory effect on insulin secretion. These results suggest that the action of leptin may be one mechanism by which excess adipose tissue could acutely impair carbohydrate metabolism. ( J. Clin. Invest. 1997. 100:2729-2736.)

show abstract

Temporal relationship between inositol polyphosphate formation and increases in cytosolic Ca2+ in quiescent 3T3 cells stimulated by platelet-derived growth factor, bombesin and vasopressin.

Cited by 123 publications

References 47 publications

Platelet-derived growth factor stimulates formation of active p21ras.GTP complex in Swiss mouse 3T3 cells.

Platelet-derived growth factor stimulates formation of active p21ras.GTP complex in Swiss mouse 3T3 cells.

Neuropeptide-Induced Androgen Independence in Prostate Cancer Cells: Roles of Nonreceptor Tyrosine Kinases Etk/Bmx, Src, and Focal Adhesion Kinase

Leptin rapidly suppresses insulin release from insulinoma cells, rat and human islets and, in vivo, in mice.

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