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Wu F, He J, Deng Q, Chen J, Peng M, Xiao J, Zeng Y, Yi L, Li Z, Tian R, Jiang Z. Neuroglobin inhibits pancreatic cancer proliferation and metastasis by targeting the GNAI1/EGFR/AKT/ERK signaling axis. Biochem Biophys Res Commun 2023; 664:108-116. [PMID: 37141638 DOI: 10.1016/j.bbrc.2023.04.080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Revised: 04/11/2023] [Accepted: 04/23/2023] [Indexed: 05/06/2023]
Abstract
Pancreatic cancer is an extremely aggressive malignancy with a very disappointing prognosis. Neuroglobin (NGB), a member of the globin family, has been demonstrated to have a significant role in a variety of tumor forms. The possible role of NGB as a tumor suppressor gene in pancreatic cancer was investigated in this work. Information from the public dataset TCGA combined with GTEx was used to analyze the finding that NGB was commonly downregulated in pancreatic cancer cell lines and tissues, correlating with patient age and prognosis. The expression of NGB in pancreatic cancer was investigated via RT-PCR, qRT-PCR, and Western blot experiments. In-vitro and in-vivo assays, NGB elicited cell cycle arrest in the S phase and apoptosis, hindered migration and invasion, reversed the EMT process, and suppressed cell proliferation and development. The mechanism of action of NGB was predicted via bioinformatics analysis and validated using Western blot and co-IP experiments revealed that NGB inhibited the EGFR/AKT/ERK pathway by binding to and reducing expression of GNAI1 and p-EGFR. In addition, pancreatic cancer cells overexpressing NGB showed increased drug sensitivity to gefitinib (EGFR-TKI). In conclusion, NGB inhibits pancreatic cancer progression by specifically targeting the GNAI1/EGFR/AKT/ERK signaling axis.
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Affiliation(s)
- Fan Wu
- Department of Gastroenterology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, 400016, China
| | - Jin He
- Department of Gastroenterology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, 400016, China
| | - Qianxi Deng
- Department of Gastroenterology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, 400016, China
| | - Jun Chen
- Department of Gastroenterology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, 400016, China
| | - Mingyu Peng
- Department of Respiratory & Critical Care Medicine, The First Affiliated Hospital of Chongqing Medical University, Chongqing, 400016, China
| | - Jiayi Xiao
- West China School of Medicine and West China Hospital, Sichuan University, #37 Guoxue Alley, Wuhou District, Chengdu, Sichuan Province, PR China
| | - Yiwei Zeng
- CHINA MEDICAL UNIVERSITY, No.77 Puhe Road, Shenyang North New Area, Shenyang, Liaoning Province, PR China
| | - Lin Yi
- CHONGQING MEDICAL UNIVERSITY, 1 Yixueyuan Road, Yuzhong District, Chongqing, 400016, PR China
| | - Zhuoqing Li
- Chongqing Key Laboratory of Translational Research for Cancer Metastasis and Individualized Treatment, Chongqing University Cancer Hospital, Chongqing, 400030, China
| | - Rui Tian
- Chongqing Key Laboratory of Translational Research for Cancer Metastasis and Individualized Treatment, Chongqing University Cancer Hospital, Chongqing, 400030, China
| | - Zheng Jiang
- Department of Gastroenterology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, 400016, China.
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Abstract
Embryogenesis can be paralleled and contrasted with cancerous cell proliferation; both embryogenesis and cancer are associated with extremely rapid cell proliferation. However, unlike cancer, embryogenesis is characterized by a delicate balance of proliferative and anti-proliferative processes. We have found two chromatographically separated fractions derived from human embryonal neural tissue extracts that significantly suppress the proliferation of human breast cancer cells. The reduction in cell number was time dependent, with maximal inhibition (70%) observed after 4 days of incubation while maintaining cell viability. The anti-proliferative effect was also evidenced by decreased [3H]-thymidine incorporation. Significant inhibition of proliferation of osteosarcoma, fibrosarcoma, and Balb/c 3T3 cell lines was also obtained with a low concentration of the active fractions. Embryonal factors inhibited mouse and rat cell lines, indicating cross-species effectiveness. The SDS-PAGE of the biologically active approximately 10.7 kDa region revealed several protein bands, while the biologically active approximately 4.5 kDa fraction contained only weakly stainable bands. Thus, the embryo contains factors that control the proliferation of malignant cells. These potent and possibly novel compounds should be investigated for their potential therapeutic role in cancer and other proliferative disorders.
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Affiliation(s)
- E R Barnea
- Biospectrum Medical Corporation, Cherry Hill, New Jersey, USA
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3
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Kitten AM, Hymer TK, Katz MS. Bidirectional modulation of parathyroid hormone-responsive adenylyl cyclase by protein kinase C. THE AMERICAN JOURNAL OF PHYSIOLOGY 1994; 266:E897-904. [PMID: 8023920 DOI: 10.1152/ajpendo.1994.266.6.e897] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The temporal pattern with which phorbol 12-myristate 13-acetate (PMA), an activator of protein kinase C (PKC), modulates parathyroid hormone (PTH)-responsive adenylyl cyclase (AC) was evaluated in a clonal osteoblast-like cell line (UMR-106). Brief (< or = 1 h) exposure of UMR-106 cells to PMA enhanced PTH stimulation of AC, whereas more prolonged PMA treatment decreased the PTH response, with maximum inhibition occurring at < or = 6 h. PMA treatment also resulted in initial activation followed by downregulation of PKC. Exposure of cells to 1,2-dioctanoyl-sn-glycerol, which activated but did not downregulate PKC, resulted in bidirectional modulation of PTH-responsive AC identical to that produced by PMA. Prolonged PMA exposure decreased PTH receptor number, as determined by radioligand binding studies, and reduced PTH receptor mRNA levels, assessed by Northern blot analysis. Forskolin activation of the catalytic subunit of AC was also decreased after prolonged PMA treatment. The results suggest that activation of PKC sequentially stimulates and then inhibits PTH responsiveness. Inhibition of the PTH response occurs by PKC actions exerted on the PTH receptor and the AC catalytic subunit.
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Affiliation(s)
- A M Kitten
- Department of Physiology, University of Texas Health Science Center, San Antonio
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4
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Rao LG, Wylie JN. Modulation of parathyroid hormone-sensitive adenylate cyclase in ROS 17/2.8 cells by dexamethasone 1,25-dihydroxyvitamin D3 and protein kinase C. BONE AND MINERAL 1993; 23:35-47. [PMID: 8274878 DOI: 10.1016/s0169-6009(08)80089-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
We tested whether the protein kinase C (PKC) modulation of PTH-sensitive adenylate cyclase in ROS 17/2.8 cells is affected by the glucocorticoid dexamethasone and the vitamin D hormone 1,25-dihydroxyvitamin D3 [1,25(OH)2D3]. Basal and PTH- and forskolin-stimulated adenylate cyclase activities were determined in the presence or absence of 100 nM phorbol 12-myristate 13-acetate (PMA), the activator of PKC, in ROS 17/2.8 cells that had been previously cultured with or without dexamethasone or 1,25(OH)2D3. Dexamethasone treatment increased the basal, PMA-, PTH-, (PTH + PMA)- and (forskolin + PMA)-sensitive adenylate cyclase while 1,25(OH)2D3 decreased these effects. The stimulatory and inhibitory effects were dose-dependent with respect to dexamethasone and 1,25(OH)2D3, respectively. Dexamethasone increased, while 1,25(OH)2D3 decreased the maximal activity of both PTH-sensitive and PKC-modulated PTH-sensitive adenylate cyclase without affecting the half-maximal concentration (ED50) of PTH required for the activation of the enzyme. Additionally, dexamethasone, 1,25(OH)2D3 and PKC did not affect each other's ED50. Our results suggest that the effects of dexamethasone, 1,25(OH)2D3 and PKC on PTH-sensitive adenylate cyclase in ROS 17/2.8 cells are independent of each other.
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Affiliation(s)
- L G Rao
- Division of Endocrinology and Metabolism, St. Michael's Hospital, Toronto, Ontario, Canada
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5
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Freyaldenhoven AM, Gutierrez GE, Lifschitz MD, Katz MS. Protein kinase C differentially modulates PTH- and PGE2-sensitive adenylate cyclase in osteoblast-like cells. THE AMERICAN JOURNAL OF PHYSIOLOGY 1992; 262:E87-95. [PMID: 1733255 DOI: 10.1152/ajpendo.1992.262.1.e87] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The effects of phorbol 12-myristate 13-acetate (PMA), a known activator of protein kinase C, on receptor-mediated stimulation of adenylate cyclase were evaluated in a rat osteosarcoma cell line (UMR-106) with the osteoblast phenotype. Pretreatment of UMR-106 cells with PMA increased parathyroid hormone (PTH)-stimulated adenylate cyclase activity and inhibited prostaglandin E2 (PGE2)-responsive enzyme activity. In addition, PMA enhanced enzyme activation by forskolin, which is thought to exert a direct stimulatory action on the catalytic subunit of adenylate cyclase. The regulatory effects of PMA were concentration dependent and of rapid onset (less than or equal to 1 min). Treatment with PMA also resulted in translocation of protein kinase C activity from the cytosol to the particulate cell fraction. Pertussis toxin, which attenuates inhibition of adenylate cyclase mediated by the inhibitory guanine nucleotide-binding regulatory protein (Gi), augmented PTH-sensitive adenylate cyclase activity and reduced the incremental increase in PTH response produced by PMA. The results suggest that activation of protein kinase C increases PTH-stimulated adenylate cyclase activity by actions on Gi and/or the catalytic subunit and decreases PGE2 responsiveness by a mechanism involving the PGE2 receptor.
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Affiliation(s)
- A M Freyaldenhoven
- Department of Medicine, University of Texas Health Science Center, San Antonio
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6
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Ransjö M, Lerner UH. Effects of phorbol esters and pertussis toxin on calcitonin-stimulated accumulation of cyclic AMP in neonatal mouse calvarial bones. Calcif Tissue Int 1991; 49:284-7. [PMID: 1662113 DOI: 10.1007/bf02556219] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Calcitonin (CT) is a well-known inhibitor of osteoclastic bone resorption both in vivo and in vitro. The effect is mediated by activation of adenylate cyclase and subsequent increased levels of cyclic AMP (cAMP). We report here that CT-induced (30 nmol/liter) accumulation of cAMP in cultured neonatal mouse calvaria is enhanced two-fold by 12-O-tetradecanoylphorbol-13-acetate (TPA; 100 nmol/liter) and phorbol 12,13-dibutyrate (PDBU; 100 nmol/liter), two protein kinase C (PKC)-activating phorbol esters, whereas phorbol 13-monoacetate (phorb-13; 100 nmol/liter), a related compound that does not activate PKC, has no effect. The ability of TPA and PDBU to enhance CT-stimulated cAMP accumulation was obtained also in the presence of indomethacin (1 mumol/liter). Kinetic studies revealed that TPA enhanced the cAMP response to CT at all the time points at which CT had a significant effect per se and that TPA did not alter the time-course of the cAMP response to CT. Treatment with pertussis toxin (100 ng/ml) enhanced cAMP response to parathyroid hormone (10 nmol/liter) and prostaglandin E2, but not to CT. From these data it is concluded that PKC, but not pertussis toxin-sensitive guanyl nucleotide-binding proteins (G-proteins), can interact with and modify the signal transducing system for CT in osteoclasts.
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Affiliation(s)
- M Ransjö
- Department of Orthodontics, University of Umeå, Sweden
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7
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Ransjö M. Protein kinase C activating phorbolesters enhance the cyclic AMP response to parathyroid hormone, forskolin and choleratoxin in mouse calvarial bones and rat osteosarcoma cells. Biosci Rep 1991; 11:203-11. [PMID: 1662087 DOI: 10.1007/bf01136854] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The protein kinase C-(PKC) activating phorbol esters 12-O-tetradecanoylphorbol-13-acetate (TPA; 100 nmol/l) and phorbol 12,13-dibutyrate (PDBU; 100 nmol/l) enhanced basal cyclin AMP accumulation in cultured neonatal mouse calvaria. The cyclic AMP response to parathyroid hormone (PTH; 10 nmol/l) and the adenylate cyclase activators forskolin (1-3 mumol/l) and choleratoxin (0.1 mumg/ml) was potentiated in a more than additive manner by TPA and PDBU. In contrast, phorbol 13-monoacetate (phorb-13; 100 nmol/l), a related compound but inactive on PKC, had no effect on basal or stimulated cyclic AMP accumulation. In the presence of indomethacin (1 mumol/l), TPA and PDBU had no effect on cyclic AMP accumulation in calvarial bones per se, but were still able to cause a significant enhancement of the response to PTH, forskolin and choleratoxin. PTH-, forskolin- and choleratoxin-stimulated cyclic AMP accumulation in rat osteosarcoma cells UMR 106-01 was synergistically potentiated by TPA and PDBU, but not by phorb.-13. These data indicate that PKC enhances cyclic AMP formation and that the level of interaction may be at, or distal to, adenylate cyclase.
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Affiliation(s)
- M Ransjö
- Department of Oral Pathology, University of Umeå, Sweden
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8
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Bos MP, van Leeuwen JP, Herrmann-Erlee MP. Modulation of responsiveness to cAMP stimulating agonists by phorbol ester in fetal rat osteoblasts. J Cell Physiol 1991; 147:87-92. [PMID: 1709941 DOI: 10.1002/jcp.1041470112] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
We studied the effect of activation of protein kinase C (PKC) by a phorbol ester on cAMP accumulation in fetal rat osteoblasts. Activation of PKC by phorbol 12-myristate 13-acetate (PMA) caused a potentiation of cAMP accumulation induced by parathyroid hormone (PTH), forskolin, and cholera toxin. The results suggest that the potentiating effect of PMA on PTH-induced cAMP accumulation was not due to an effect on the PTH-receptor nor to an effect on cAMP degradation, as the effect of PMA persisted in the presence of a phosphodiesterase inhibitor. Pretreatment of the cells with pertussis toxin did not prevent the action of PMA, indicating that PMA does not act via the inhibitory G-protein. PMA had a biphasic effect on prostaglandin E2 (PGE2)-induced cAMP accumulation; i.e., at concentrations greater than or equal to 10(-6) M, PMA potentiated the PGE2-induced cAMP response but PMA attenuated cAMP accumulation induced by concentrations of PGE2 less than or equal to 5.10(77) M. From our data we conclude that PKC can interact with a stimulated cAMP pathway in a stimulatory and inhibitory manner. Potentiation of cAMP accumulation is probably due to modification of the adenylate cyclase complex, whereas attenuation of stimulated cAMP accumulation appears to be due to an effect on a different site of the cAMP generating pathway, which may be specific to PGE2-induced cAMP accumulation.
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Affiliation(s)
- M P Bos
- Laboratory of Cell Biology and Histology, University of Leiden, The Netherlands
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9
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Houslay MD. 'Crosstalk': a pivotal role for protein kinase C in modulating relationships between signal transduction pathways. EUROPEAN JOURNAL OF BIOCHEMISTRY 1991; 195:9-27. [PMID: 1846812 DOI: 10.1111/j.1432-1033.1991.tb15671.x] [Citation(s) in RCA: 273] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- M D Houslay
- Department of Biochemistry, University of Glasgow, Scotland, UK
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10
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Abstract
In a human B cell line in which we previously demonstrated an inverse relationship between cyclic adenosine monophosphate (cAMP) content and immunoglobulin secretion, the phorbol ester, phorbol myristate acetate, (PMA), was shown to augment the cAMP elevating ability of cholera toxin (CT), suggesting a regulatory linkage between the two transmembrane signaling pathways, cAMP and phospholipid (J. Immunol. 141, 1678-1686, 1988). We now extend these studies and provide additional evidence that activated protein kinase C, a principal product of the activation of the hydrolytic phospholipid pathway, plays a direct role in the augmentation of cAMP levels in cells stimulated by diverse cAMP-elevating ligands. Prostaglandin E1 (PGE1), forskolin (FSK) and CT, all of which demonstrated a concentration and time-dependent elevation of intracellular cAMP, produced even greater (up to twofold) elevations of cAMP in the presence of PMA or the diacylglycerol analogs, 1,2-dioctanoylglycerol (DiC8), and 1-oleoyl-2-acetylglycerol (OAG). In the absence of CT, PGE1, or FSK, these protein kinase C activators produced only small increases in cAMP content of the cells. Several tests of protein kinase C specificity in these PMA-, DiC8-, and OAG-induced augmentations were made: (i) only phorbol esters known to activate protein kinase C worked, (ii) PMA augmentation was abolished by down-regulation of protein kinase C, (iii) Staurosporine (a known inhibitor of protein kinase C) selectively inhibited the effects of PMA on cAMP generation and on immunoglobulin secretion in the LA350 cell line.
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Affiliation(s)
- C L Patke
- Department of Pediatrics, Baylor College of Medicine, Houston, Texas 77030
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11
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Dobson PR, Brown BL, Michelangeli VP, Short AD, Moseley JM, Russell RG, Martin TJ. Interactive regulation of signalling pathways in bone cells: possible modulation of PGE2-stimulated adenylyl cyclase activity by protein kinase C. BIOCHIMICA ET BIOPHYSICA ACTA 1990; 1052:323-6. [PMID: 2334740 DOI: 10.1016/0167-4889(90)90228-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
We have reported previously that tumour-promoting phorbol esters modulate both basal and vasoactive intestinal polypeptide (VIP)-stimulated adenylyl cyclase activity in GH3 (an established pituitary cell line). Here, we probe the receptor and cell specificity of this response. Experiments were performed in the presence of isobutylmethylxanthine. Unlike the response in GH3 cells, the tumour-promoting phorbol ester (tetradecanoyl phorbol acetate (TPA] did not affect either basal adenylyl cyclase activity nor VIP-stimulated activity in the rat osteosarcoma subclones UMR 106-01 and UMR 106-06. In addition, the cyclase responses to parathyroid hormone (PTH), and, in the case of UMR 106-06, to calcitonin were unaffected by tumour-promoting phorbol ester. However, prostaglandin E2-stimulated cyclase activity in both of these subclones was attenuated in a dose-dependent manner.
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Affiliation(s)
- P R Dobson
- Department of Human Metabolism and Clinical Biochemistry, University of Sheffield Medical School, U.K
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12
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Rao LG, Murray TM. Calcium and protein kinase C enhance parathyroid hormone- and forskolin-stimulated adenylate cyclase in ROS 17/2.8 cells. Calcif Tissue Int 1989; 45:354-9. [PMID: 2509026 DOI: 10.1007/bf02556006] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Both parathyroid hormone (PTH)- and forskolin-stimulated adenylate cyclase activities in ROS 17/2.8 cells are enhanced by increasing the medium concentrations of CaCl2 from 10(-5) M to 3 x 10(-3) M. The ED50 for CaCl2 for both PTH- and forskolin-stimulated activities are similar. The tumor-promoting phorbol ester phorbol 12-myristate 13-acetate (PMA), a known activator of protein kinase C, also enhanced both PTH- and forskolin-stimulated adenylate cyclase. This action of PMA is specific for protein kinase C as phorbol esters that are not activators of protein kinase C had no effect on the system. The combined effects of PMA and CaCl2 were more than additive. The separate and combined effects of PMA and CaCl2 changed the rate of activation of the enzyme (Vmax) but did not modify the ED50 for PTH or for forskolin. PMA and CaCl2 both enhanced the potentiating effect of submaximal dose of forskolin on PTH-stimulated adenylate cyclase. It is concluded that calcium and PMA enhance PTH-sensitive adenylate cyclase and increase the production of cAMP by a mechanism that appears to involve the catalytic subunit of the enzyme and probably its interaction with a guanine nucleotide regulatory protein.
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Affiliation(s)
- L G Rao
- Division of Endocrinology and Metabolism, St. Michael's Hospital, Toronto, Ontario, Canada
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13
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Evans DB, Russell RG, Brown BL, Dobson PR. Agents affecting adenylate cyclase activity modulate the stimulatory action of 1,25-dihydroxyvitamin D3 on the production of osteocalcin by human bone cells. Biochem Biophys Res Commun 1989; 164:1076-85. [PMID: 2480111 DOI: 10.1016/0006-291x(89)91779-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The stimulation of osteocalcin synthesis by human osteoblast-like cells in response to 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) is antagonised by several bone regulatory agents. We have shown that agents which activate adenylate cyclase inhibit this action of 1,25(OH)2D3 on human osteoblast-like cells. Activation of adenylate cyclase, either via the stimulatory GTP-binding protein using cholera toxin, or directly at the catalytic via the stimulatory GTP-binding protein using cholera toxin, or directly at the catalytic subunit using forskolin, results in a suppression of osteocalcin synthesis. Whilst the activation of adenylate cyclase induces this inhibitory response, neither exogenous dibutyryl cyclic AMP nor the phosphodiesterase inhibitor, IBMX, exerted any apparent effect on the production of osteocalcin. The tumour promoting phorbol ester, 4 beta-phorbol 12,13-dibutyrate, also inhibited 1,25(OH)2D3-stimulated osteocalcin production. This was not apparent in response to the non-tumour promoting phorbol ester 4 beta-phorbol suggesting the involvement of protein kinase C.
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Affiliation(s)
- D B Evans
- Department of Human Metabolism and Clinical Biochemistry, University of Sheffield Medical School, UK
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14
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Rao LG, March M, Murray TM. Calcium modulation of the parathyroid hormone-sensitive adenylate cyclase in ROS 17/2.8 cells: effects of N-(6-aminohexyl-5-Cl-naphthalene sulfonamide) (W-7) and trifluoperazine (TFP). BONE AND MINERAL 1989; 7:191-204. [PMID: 2558749 DOI: 10.1016/0169-6009(89)90077-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The calcium modulation of the cyclic 3',5'-adenosine monophosphate (cAMP) response to parathyroid hormone (PTH) was studied in a clonal osteosarcoma cell line ROS 17/2.8. CaCl2 was found to stimulate the PTH-sensitive cAMP response of intact cells. At the maximal concentration of 1 mM CaCl2, the maximum response to PTH was increased, but the ED50 for PTH and the time course of maximal cAMP production were not affected. Verapamil blunted, while the cation ionophore A23187 enhanced, the stimulatory effect of CaCl2. Trifluoperazine (TFP) and N-(6-aminohexyl-5-Cl-naphthalene sulfonamide) (W-7) inhibited the stimulatory effect of CaCl2. In membranes prepared in the presence of 0.1 mM CaCl2, a biphasic effect of CaCl2 was demonstrated: stimulation at concentrations of 60-100 microM, and an inhibition above 200 microM, when adenylate cyclase was assayed in the presence of 200 microM EGTA. Addition of exogenous calmodulin to membranes prepared in the presence of EGTA did not have any effect on the PTH-sensitive adenylate cyclase activity, suggesting that endogenous calmodulin was not effectively stripped from the membranes by EGTA treatment. It is concluded that Ca2+ has both a stimulatory and an inhibitory role in modulating PTH-sensitive adenylate cyclase in ROS 17/2.8 cells by as yet unknown mechanisms, and that the involvement of endogenous calmodulin is implicated.
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Affiliation(s)
- L G Rao
- Division of Endocrinology and Metabolism, St. Michael's Hospital, Toronto, Ontario, Canada
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15
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Pines M, Yosif B, Hurwitz S. Modulation of responsiveness of the adenylate cyclase system in avian chondroprogenitor cells by pertussis toxin, PTH, and PGE2. J Bone Miner Res 1989; 4:743-50. [PMID: 2554689 DOI: 10.1002/jbmr.5650040514] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Chondroprogenitor cells, derived from avian tibia epiphyseal growth plate, were cultured in vitro. Incubation of these cells with pertussis toxin augmented their cAMP response to parathyroid hormone (PTH), attenuated the response to forskolin, but did not modify the response to PGE2. Pertussis toxin modulation of the cAMP response was accompanied by ADP ribosylation of two proteins with molecular weights of 39 and 40 kD. Using specific antibodies, the 39 kD protein was identified as the inhibitory guanine nucleotide binding protein (Gi) of the adenylate cyclase system. The other ADP-ribosylated protein has not been identified. Preincubation of the chondroprogenitor cells with PTH or PGE2 resulted in time-dependent heterologous desensitization of the cAMP response to a second challenge of either hormone. The cells did not recover from the densitization for at least 18 h after removal of the hormones. PTH and PGE2 treatment did not affect the cAMP response to forskolin and cholera toxin. The PTH-dependent cAMP production was also not altered by forskolin treatment. PTH homologous desensitization was not affected by pertussis toxin treatment, but the heterologous desensitization due to PGE2 was significantly attenuated. These results suggest that exposure of chondroprogenitor cells to PTH and PGE2 results in heterologous desensitization of the cAMP response. The desensitization is not due to changes in the adenylate cyclase activity. The pertussis toxin-sensitive G proteins are involved in the PTH heterologous rather than homologous desensitization of the cAMP response.
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Affiliation(s)
- M Pines
- Institute of Animal Science, Volcani Center, Bet Dagan, Israel
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16
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Orr GL, Gole JW, Gupta J, Downer RG. Modulation of octopamine-mediated production of cyclic AMP by phorbol-ester-sensitive protein kinase C in an insect cell line. BIOCHIMICA ET BIOPHYSICA ACTA 1988; 970:324-32. [PMID: 2840971 DOI: 10.1016/0167-4889(88)90132-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The presence of protein kinase C (EC 2.7.1.37) in an insect cell line has been demonstrated. Phorbol 12-myristate 13-acetate (PMA), in micromolar concentrations, activated protein kinase C with a translocation of the enzyme from the cytosol to the particulate fraction. Cyclic AMP production in the presence of PMA, octopamine and a combination of both increased in a dose-dependent and time-dependent fashion. The biologically inactive 4 alpha-phorbol 12,13-didecanoate had no effect on protein kinase C activity or on octopamine-mediated cyclic AMP production. Pretreatment of the cells with pertussis toxin had no effect on the response of cells to octopamine or PMA. However, pretreatment with cholera toxin resulted in increased cyclic AMP production which was further enhanced when both cholera toxin and PMA were used in combination. Our data indicate that the octopamine-mediated cyclic AMP production is modulated by protein kinase C.
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Affiliation(s)
- G L Orr
- Department of Biology, University of Waterloo, Canada
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17
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Spiegel AM. Guanine nucleotide binding proteins and signal transduction. VITAMINS AND HORMONES 1988; 44:47-101. [PMID: 2853488 DOI: 10.1016/s0083-6729(08)60693-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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Spiegel A, Carter A, Brann M, Collins R, Goldsmith P, Simonds W, Vinitsky R, Eide B, Rossiter K, Weinstein L. Signal transduction by guanine nucleotide-binding proteins. RECENT PROGRESS IN HORMONE RESEARCH 1988; 44:337-75. [PMID: 3146116 DOI: 10.1016/b978-0-12-571144-9.50015-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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Escudero F, Carmena MJ, Prieto JC. Tumor-promoting phorbol esters interfere with the vasoactive intestinal peptide receptor/effector system in rat prostatic epithelial cells. Biochem Biophys Res Commun 1987; 149:221-6. [PMID: 2825698 DOI: 10.1016/0006-291x(87)91627-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Pretreatment of rat prostatic epithelial cells with the tumor-promoting phorbol ester 4 beta-phorbol 12-myristate 13-acetate resulted in a decrease of both the potency of vasoactive intestinal peptide (VIP) upon the stimulation of cyclic AMP accumulation and the affinity of the receptors of this peptide. These effects were dose-dependent and could be reproduced by other stimulators of protein kinase C (PKC). Thus, it is conceivably that phosphorylation of VIP receptors by PKC regulates VIP receptor function in the prostate gland.
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Affiliation(s)
- F Escudero
- Departamento de Bioquímica y Biología Molecular, Universidad de Alcalá de Henares, Madrid, Spain
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