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Nůsková H, Serebryakova MV, Ferrer-Caelles A, Sachsenheimer T, Lüchtenborg C, Miller AK, Brügger B, Kordyukova LV, Teleman AA. Stearic acid blunts growth-factor signaling via oleoylation of GNAI proteins. Nat Commun 2021; 12:4590. [PMID: 34321466 PMCID: PMC8319428 DOI: 10.1038/s41467-021-24844-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Accepted: 07/08/2021] [Indexed: 01/13/2023] Open
Abstract
Covalent attachment of C16:0 to proteins (palmitoylation) regulates protein function. Proteins are also S-acylated by other fatty acids including C18:0. Whether protein acylation with different fatty acids has different functional outcomes is not well studied. We show here that C18:0 (stearate) and C18:1 (oleate) compete with C16:0 to S-acylate Cys3 of GNAI proteins. C18:0 becomes desaturated so that C18:0 and C18:1 both cause S-oleoylation of GNAI. Exposure of cells to C16:0 or C18:0 shifts GNAI acylation towards palmitoylation or oleoylation, respectively. Oleoylation causes GNAI proteins to shift out of cell membrane detergent-resistant fractions where they potentiate EGFR signaling. Consequently, exposure of cells to C18:0 reduces recruitment of Gab1 to EGFR and reduces AKT activation. This provides a molecular mechanism for the anti-tumor effects of C18:0, uncovers a mechanistic link how metabolites affect cell signaling, and provides evidence that the identity of the fatty acid acylating a protein can have functional consequences.
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Affiliation(s)
- Hana Nůsková
- German Cancer Research Center (DKFZ), Heidelberg, Germany
- Heidelberg University, Heidelberg, Germany
| | - Marina V Serebryakova
- A.N. Belozersky Institute of Physico-Chemical Biology, M.V. Lomonosov Moscow State University, Moscow, Russia
| | - Anna Ferrer-Caelles
- German Cancer Research Center (DKFZ), Heidelberg, Germany
- Heidelberg University, Heidelberg, Germany
| | | | | | - Aubry K Miller
- German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Britta Brügger
- Heidelberg University Biochemistry Center (BZH), Heidelberg, Germany
| | - Larisa V Kordyukova
- A.N. Belozersky Institute of Physico-Chemical Biology, M.V. Lomonosov Moscow State University, Moscow, Russia
| | - Aurelio A Teleman
- German Cancer Research Center (DKFZ), Heidelberg, Germany.
- Heidelberg University, Heidelberg, Germany.
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The biological activities of protein/oleic acid complexes reside in the fatty acid. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2013; 1834:1125-43. [DOI: 10.1016/j.bbapap.2013.02.041] [Citation(s) in RCA: 70] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2013] [Revised: 02/18/2013] [Accepted: 02/20/2013] [Indexed: 12/12/2022]
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Hang TC, Lauffenburger DA, Griffith LG, Stolz DB. Lipids promote survival, proliferation, and maintenance of differentiation of rat liver sinusoidal endothelial cells in vitro. Am J Physiol Gastrointest Liver Physiol 2012; 302:G375-88. [PMID: 22075778 PMCID: PMC3287397 DOI: 10.1152/ajpgi.00288.2011] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Primary rat liver sinusoidal endothelial cells (LSEC) are difficult to maintain in a differentiated state in culture for scientific studies or technological applications. Relatively little is known about molecular regulatory processes that affect LSEC differentiation because of this inability to maintain cellular viability and proper phenotypic characteristics for extended times in vitro, given that LSEC typically undergo death and detachment around 48-72 h even when treated with VEGF. We demonstrate that particular lipid supplements added to serum-free, VEGF-containing medium increase primary rat liver LSEC viability and maintain differentiation. Addition of a defined lipid combination, or even oleic acid (OA) alone, promotes LSEC survival beyond 72 h and proliferation to confluency. Moreover, assessment of LSEC cultures for endocytic function, CD32b surface expression, and exhibition of fenestrae showed that these differentiation characteristics were maintained when lipids were included in the medium. With respect to the underlying regulatory pathways, we found lipid supplement-enhanced phosphatidylinositol 3-kinase and MAPK signaling to be critical for ensuring LSEC function in a temporally dependent manner. Inhibition of Akt activity before 72 h prevents growth of SEC, whereas MEK inhibition past 72 h prevents survival and proliferation. Our findings indicate that OA and lipids modulate Akt/PKB signaling early in culture to mediate survival, followed by a switch to a dependence on ERK signaling pathways to maintain viability and induce proliferation after 72 h. We conclude that free fatty acids can support maintenance of liver LSEC cultures in vitro; key regulatory pathways involved include early Akt signaling followed by ERK signaling.
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Affiliation(s)
- Ta-Chun Hang
- 1Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts; and
| | - Douglas A. Lauffenburger
- 1Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts; and
| | - Linda G. Griffith
- 1Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts; and
| | - Donna B. Stolz
- 2Department of Cell Biology & Physiology, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania
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Yano K. Lipid metabolic pathways as lung cancer therapeutic targets: a computational study. Int J Mol Med 2011; 29:519-29. [PMID: 22211244 PMCID: PMC3573709 DOI: 10.3892/ijmm.2011.876] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2011] [Accepted: 12/13/2011] [Indexed: 12/20/2022] Open
Abstract
Inhibitors of lipid metabolic pathways, particularly drugs targeting the mevalonate pathway, have been suggested to be valuable in enhancing the effectiveness of epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) and these compounds may also be effective in patients with inherent or acquired resistance to EGFR-TKIs. The present study examined gene expression profiles in lung adenocarcinoma to characterize the interaction between growth factor signals and lipid metabolic pathways at the transcriptional level. Gene expression correlation analysis showed that genes involved in the mevalonate pathway and unsaturated fatty acid synthesis were negatively correlated with the expression of EGFR, MET and other growth factor receptor genes, as well as with the expression of genes involved in cell migration and adhesion. On the other hand, the expression of genes related to cell cycle progression, DNA repair and DNA replication were positively correlated with the metabolic pathway genes mentioned above, and a significant number of such genes had promoter domains for nuclear factor Y (NFY). Genes whose expression showed a positive correlation with NFY expression and mevalonate pathway genes were found to exhibit protein-protein interactions with several 'hub' genes, including BRCA1, that have been associated with both lung cancer and cell division. These results support the idea that inhibition of lipid metabolic pathways may be valuable as an alternative therapeutic option for the treatment of lung adenocarcinoma, and suggest that NFY is a possible molecular target for such efforts.
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Affiliation(s)
- Kojiro Yano
- Faculty of Information Science and Technology, Osaka Institute of Technology, Hirakata-City, Osaka, Japan.
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Huang P, Hawthorne WJ, Peng A, Angeli GL, Medbury HJ, Fletcher JP. Calcium channel antagonist verapamil inhibits neointimal formation and enhances apoptosis in a vascular graft model. Am J Surg 2001; 181:492-8. [PMID: 11513772 DOI: 10.1016/s0002-9610(01)00615-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
BACKGROUND The potential of the calcium channel antagonist verapamil to cause apoptosis (programmed cell death) is of considerable importance in arterial injury where the loss of smooth muscle cells may contribute to a reduction in intimal hyperplasia development. The aim of this study was to determine whether verapamil induces vascular cell apoptosis after carotid artery synthetic grafting. METHODS Thirty-two adult-female Merino sheep received gelatin sealed fusiform shape-Dacron grafts into the left common carotid artery at day 0. After operation animals were randomly allocated to either a control group or one of three treatment groups (groups 2, 3, and 4). Group 1 animals (n = 9) received no treatment. For the treatment groups, intravenous verapamil was given at a rate of 0.5 mg/kg per day in two divided doses. Group 2, 3, and 4 sheep were treated for 1, 2, and 4 weeks, respectively. Animals were sacrificed at 4 weeks. Apoptosis was detected by terminal deoxynucleotidyl transferase-mediated dUTP-fluorescent labelling. Proliferating cells and their phenotype were determined by doublestaining with antiproliferation cellular nuclei antigen and anti-alpha-actin or anti-HAM-56. RESULTS There were significantly more apoptotic cells in the perigraft adventitia in the 4-week treatment group than in the control group (P <0.05). The average number of proliferating cells at 2 and 4 weeks in the intima were significantly less than in the control (P <0.05). The average numbers of macrophages inside graft matrix in the 2 and 4 weeks treatment groups were significantly less than for the control (P <0.05). The number of proliferating cells inside the graft was significantly lower at 4 weeks compared with control (P <0.05). There was negative correlation between intimal PCNA expression and perigraft apoptotic expression level (P <0.05). CONCLUSION The antihypertensive agent verapamil inhibits intimal hyperplasia through enhancing adventitial cell apoptosis and inhibiting intimal cell proliferation after vascular grafting.
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Affiliation(s)
- P Huang
- Department of Surgery, University of Sydney, Westmead Hospital, NSW, 2145, Westmead, Australia
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Cordido F, Peñalva A, Martinez T, Casanueva FF, Dieguez C. Effect of acute pharmacological modulation of plasma free fatty acids on GH secretion in acromegalic patients. Clin Endocrinol (Oxf) 2001; 54:509-13. [PMID: 11318787 DOI: 10.1046/j.1365-2265.2001.01249.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVES In acromegaly GH secretion is markedly increased due in most cases to a GH secreting pituitary adenoma. GH secretion is modulated by variations in the levels of free fatty acids (FFA). Recent studies in different clinical situations, have shown that reduction in FFA with acipimox (A) modifies somatotroph cell responsiveness. The aim of the present study was to evaluate the effect of acute pharmacological reduction of plasma FFA on both basal GH levels and GHRH-mediated GH secretion in acromegalic patients. PATIENTS Six acromegalic patients (four female, two male) aged 57 +/- 4 years., with active disease due to pituitary adenomas were studied. Four of the patients had been treated previously by surgery and/or radiotherapy. The diagnosis of active acromegaly was established by clinical assessment, increased serum IGF-I and impaired GH suppression after oral glucose. MEASUREMENTS Four tests were performed: placebo, A (250 mg, orally, - 210 minutes and - 60 minutes), GHRH (100 microg, iv, 0 minutes) and GHRH plus A. The different tests on each subject were performed in random order one week apart, each subject served as their own control. Serum GH was measured by RIA at appropriate intervals. The area under the curve (AUC) was calculated by the trapezoidal METHOD Statistical analysis was performed by Wilcoxon test. P < 0.05 was considered significant. RESULTS The administration of A induced a FFA reduction during the entire test both when administered with placebo and with GHRH: AUC (mmol/l x 90 minutes): placebo plus placebo: 88.2 +/- 7.3. Placebo plus A: 23.2 +/- 4.6 (P < 0.05). Placebo plus GHRH: 85.4 +/- 6.9. A plus GHRH: 21.8 +/- 3.8 (P < 0.05). Mean peak GH level (microg/l) after placebo plus placebo was 5.0 +/- 1.8 not significantly different than after placebo plus A with a mean peak of 6.2 +/- 2 (P = ns). Mean peak GHRH-induced GH secretion was 26.0 +/- 15.4 and was not modified by previous A administration with mean peak of 24.4 +/- 11.8 (P = ns). CONCLUSIONS In acromegalic patients acute pharmacological reduction of FFA with acipimox did not modify basal GH levels or GHRH-induced GH secretion, suggesting that the adenomatous somatotroph cell is unresponsive to physiological signals such as FFA which act at a pituitary level. These data support the hypothesis of an intrinsic neoplastic pituitary defect for the pathogenesis of acromegaly.
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Affiliation(s)
- F Cordido
- Department of Endocrinology, Hospital Juan Canalejo, La Coruña, Spain.
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Casanueva FF, Dieguez C. Interaction between body composition, leptin and growth hormone status. BAILLIERE'S CLINICAL ENDOCRINOLOGY AND METABOLISM 1998; 12:297-314. [PMID: 10083898 DOI: 10.1016/s0950-351x(98)80024-4] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Administration of growth hormone (GH) induces changes in body composition, namely, increases in both bone and lean mass and a decrease in fatty tissue. However, the contrary issue, i.e. the way in which body composition affects the secretion of GH, is highly controversial. Disease states such as obesity and chronic hypercortisolism are associated with increased adiposity and/or the central distribution of fat. Ageing, characterized by excess adiposity, is also associated with impaired secretion of GH. In these states, both spontaneous and stimulated secretion of GH is severely impeded. At the other extreme, malnutrition and fasting are both associated with increased secretion of GH when confronted with most, if not all, stimuli. As the common factor in all of these situations is the increased or decreased adiposity, or the changes in energy homeostasis, it has been postulated that adipose tissue exerts a relevant role in the control of GH secretion in man. The link between adipose tissue and GH seems to be exerted through at least two signals produced by adipocytes: free fatty acids (FFA) and the recently cloned protein, leptin. An increase in FFA blocks secretion of GH, while a decrease in FFA enhances secretion. Leptin, a hormone whose main role is to regulate the intake of food and energy expenditure, seems to regulate GH secretion by acting at the hypothalamic level. In summary, body composition affects GH secretion by way of the degree of adiposity, and free fatty acids and leptin would appear to be the messages through which adipocytes participate in the regulation of GH secretion. This framework clarifies the metabolic control of GH, a hormone with profound metabolic activities.
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Affiliation(s)
- F F Casanueva
- Department of Medicine, University of Santiago de Compostela, Spain
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Garcia-Mayor RV, Leal-Cerro A, Perez FR, Menendez C, Micic D, Pombo M, Dieguez C, Casanueva FF. Theoretical considerations in estimating the growth hormone axis in adults. Growth Horm IGF Res 1998; 8 Suppl B:93-6. [PMID: 10990140 DOI: 10.1016/s1096-6374(98)80029-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Pérez FR, Camiña JP, Menéndez C, Beiras A, Casabiell X, Casanueva FF. Cis-unsaturated free fatty acids block VIP-mediated GH and PRL secretion by perturbing the cAMP/protein kinase A pathway. Pituitary 1998; 1:25-32. [PMID: 11081180 DOI: 10.1023/a:1009962624036] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Cis-unsaturated free fatty acids (FFA) like oleic acid are strong blockers of both basal and stimulated GH secretion in vivo by acting directly on the somatotroph cell. Several lines of evidence suggest that this inhibitory action is the result of a perturbation of the function of several plasma membrane integral proteins. It has been reported recently that cis-FFA are able to block several steps in the inositolphosphates/phospholipase C/Ca2+ (InsPs/PLC/Ca2+) signal transduction pathway triggered by the activation of the TRH receptor. In this paper we present evidence showing that the inhibition of growth hormone (GH) and prolactin (PRL) secretion by cis-FFA in vitro is also exerted at several different levels on the cAMP-protein kinase A (cAMP/PKA) pathway triggered by the stimulation of the vasoactive intestinal peptide (VIP) receptor in pituitary clonal cells. By means of a sequential analysis of signal transduction events, we observed that cis-unsaturated FFA; (1) reduce the activity of adenylate cyclase; (2) perturb the activity of protein kinase A; (3) suppress the VIP-triggered Ca2+ influx, and (4) do not perturb VIP binding or the homologous desensitization of the VIP receptor.
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Affiliation(s)
- F R Pérez
- Department of Medicine, Compostela University School of Medicine, Santiago de Compostela, Spain
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Ahmed A, Kobayashi S, Shikasho T, Nishimura J, Kanaide H. Differential effects of Ca2+ channel blockers on Ca2+ transients and cell cycle progression in vascular smooth muscle cells. Eur J Pharmacol 1998; 344:323-31. [PMID: 9600669 DOI: 10.1016/s0014-2999(97)01597-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
We examined the differential effects of Ca2+ channel blockers on the elevation of the cytosolic Ca2+ concentration ([Ca2+]i) and G0/G1 transition induced by platelet-derived growth factor (PDGF) in rat aortic smooth muscle cells in primary culture. The phase of the cell cycle was determined by an immunocytochemical analysis of cell cycle-specific nuclear antigens. [Ca2+]i was monitored by fura-2 microfluorometry. The efficacy of Ca2+ channel blockers for the inhibition of [Ca2+]i elevation induced by PDGF (NiCl2 > isradipine > verapamil = diltiazem) did not parallel that for the inhibition of cell cycle progression induced by PDGF (verapamil = diltiazem > NiCl2 > isradipine). In addition, no significant correlation was observed between the extent of [Ca2+]i elevation and the extent of G0/G1 transition. We thus conclude that the inhibitory effects of Ca2+ channel blockers on the G0)/G1 transition induced by PDGF are not simply due to their inhibitory action on the [Ca2+]i elevations but instead are due to more complex unknown factors.
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Affiliation(s)
- A Ahmed
- Division of Molecular Cardiology, Research Institute of Angiocardiology, Faculty of Medicine, Kyushu University, Fukuoka, Japan
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Carro E, Señaris R, Peino R, Leal-Cerro A, Popovic V, Micic D, Dieguez C, Casanueva FF. Neuropharmacological assessment of growth hormone secretion. ACTA PAEDIATRICA (OSLO, NORWAY : 1992). SUPPLEMENT 1997; 423:12-6. [PMID: 9401532 DOI: 10.1111/j.1651-2227.1997.tb18362.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The biochemical diagnosis of individuals who are either deficient in growth hormone (GH) or who have alterations in the normal pattern of GH secretion is difficult. The uncertainty surrounding diagnosis reflects the lack of a thorough understanding of the physiology of GH secretion and of the hypothalamic hormones involved. At least three hormones are implicated: GH-releasing hormone (GHRH), somatostatin and the endogenous ligand of the GH secretagogue receptor, although the role that each plays in the release of GH is not clear from the available experimental evidence. In such a situation, most of the dynamic tests of GH secretory capacity in humans need to undergo a 'trial and error' process before being validated. The search for the 'gold standard' test of GH secretion is ongoing, and the combination of GHRH plus GH secretagogues will probably play an important role in future clinical diagnosis.
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Affiliation(s)
- E Carro
- Department of Physiology, Complejo Hospitalario de Santiago, Santiago de Compostela University, Spain
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Pérez FR, Camiña JP, Zugaza JL, Lage M, Casabiell X, Casanueva FF. cis-FFA do not alter membrane depolarization but block Ca2+ influx and GH secretion in KCl-stimulated somatotroph cells. Suggestion for a direct cis-FFA perturbation of the Ca2+ channel opening. BIOCHIMICA ET BIOPHYSICA ACTA 1997; 1329:269-77. [PMID: 9371418 DOI: 10.1016/s0005-2736(97)00111-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
It has been reported that cis-unsaturated free fatty acids (cis-FFA) block intracellular Ca2+ rise in EGFR T17 and GH3 cells by perturbing the generation of Ins(1,4,5)P3. In the present work, it was found that cis-FFA did not alter potassium-induced cell depolarization in GH3 cells, while blocking Ca2+ rise and GH secretion. Interestingly enough, saturated or trans-unsaturated FFA exert the opposite actions, i.e., they block cell depolarization without altering Ca2+ rise and hormone secretion. As depolarization activates GH3 cells via direct opening of Ca2+ channels with no generation of intracellular mediators, these results suggest that cis-FFA act by a direct perturbation of the Ca2+ channel opening.
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Affiliation(s)
- F R Pérez
- Department of Medicine, Compostela University School of Medicine and Complejo Hospitalario Universitario de Santiago, Santiago de Compostela, Spain
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Poiraudeau S, Lieberherr M, Kergosie N, Corvol MT. Different mechanisms are involved in intracellular calcium increase by insulin-like growth factors 1 and 2 in articular chondrocytes: Voltage-gated calcium channels, and/or phospholipase C coupled to a pertussis-sensitive G-protein. J Cell Biochem 1997. [DOI: 10.1002/(sici)1097-4644(19970301)64:3<414::aid-jcb8>3.0.co;2-y] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Pombo C, Bokser L, Casabiell X, Zugaza J, Capeans M, Salorio M, Casanueva F. Partial characterization of a putative new growth factor present in pathological human vitreous. Graefes Arch Clin Exp Ophthalmol 1996; 234:155-63. [PMID: 8720714 DOI: 10.1007/bf00462027] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
BACKGROUND Several growth factors have been implicated in the development of proliferative eye diseases, and some of those are present in human vitreous (HV). The effects of HV on cellular responses which modulate proliferative cell processes were studied. This study describes the partial characterization of a vitreous factor activity which does not correspond to any of the previously reported growth factors in pathological HV. METHODS Vitreous humour was obtained from medical vitrectomies, from patients with PDR and PVR. The biological activity of the vitreous factor was determined by its ability to increase cytosolic calcium concentration ([Ca2+]i), increase production of inositol phosphates, and induce cell proliferation in the cell line EGFR T17. In some experiments other cell lines, such as NIH 3T3, 3T3-L1, FRTL5, A431, PC12, Y79, and GH3, were also employed. Measurement of [Ca2+]i in cell suspensions was performed using the fluorescent Ca2+ indicator fura-2. The activity of the factor present in HV was compared with other growth factors by means of: (a) [Ca2+]i mobilization pattern, (b) sequential homologous and heterologous desensitization of receptors, (c) effects of phorbol esters on their action, and (d) inactivation after treatment with different proteolytic enzymes. RESULTS The HV-induced cell proliferation and increases in [Ca2+]i concentration were characterized by a peculiar time pattern. The different approaches used ruled out its identity with PDGF, bFGF, EGF, TGF-beta, IGFs, TNF-alpha, NGF, and other compounds such as ATP, angiotensin I, and bradykinin. Vitreous factor actions are mediated by specific receptors apparently regulated by PKC. This factor is able to induce [Ca2+]i mobilization in most of the cell lines studied, indicating that its effects are not tissue specific. CONCLUSIONS These results suggest the presence of a growth factor activity in pathological HV which may be due to the presence of an undescribed growth factor in the eye.
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Affiliation(s)
- C Pombo
- Department of Medicine, Faculty of Medicine, University of Santiago de Compostela, Spain
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15
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Casanueva FF, Perez FR, Casabiell X, Camiña JP, Cai RZ, Schally AV. Correlation between the effects of bombesin antagonists on cell proliferation and intracellular calcium concentration in Swiss 3T3 and HT-29 cell lines. Proc Natl Acad Sci U S A 1996; 93:1406-11. [PMID: 8643644 PMCID: PMC39951 DOI: 10.1073/pnas.93.4.1406] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Bombesin (BN) acts as an autocrine mitogen in various human cancers. Several pseudononapeptide BN-(6-14) analogs with a reduced peptide bond between positions 13 and 14 have been shown to suppress the mitogenic activity of BN or gastrin-releasing peptide (GRP) when assessed by radioreceptor or proliferation assays and may have significant clinical applications. The search for potent and safe BN antagonists requires the evaluation of a large series of analogs in radioreceptor and proliferation assays. In this paper, we report that the ability of BN analogs to inhibit BN-induced calcium transients in Swiss 3T3 cells shows a high correlation with their inhibitory potency as evaluated by classical proliferation tests. The assay of calcium transients allows a rapid characterization of new BN analogs (in terms of minutes rather than days) and can be adapted as a labor and cost-effective screening step in the selection of potentially relevant BN antagonists for further characterization in cell proliferation systems. We also observed that results from the assay of calcium transients in Swiss 3T3 cells can be correlated with the results of the proliferative response in HT-29 cells, a cell line that does not seem to use the same early transmembrane ionic signal system. This result suggests that the calcium pathway is not mandatory for triggering cell division by the BN receptor.
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Affiliation(s)
- F F Casanueva
- Department of Medicine, Complejo Hospitalario de Santiago, Spain
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