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Trosko JE, Chang CC. Potential Role of Intercellular Communication in the Rate-Limiting Step in Carcinogenesis. ACTA ACUST UNITED AC 2016. [DOI: 10.3109/10915818309140689] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
In order to ascertain whether there might be a scientific basis for determining practical “thresholds” for “carcinogens,” the concepts of thresholds and carcinogens were examined in the context of some current ideas on cardnogenesis. The observation that cardnogenesis seems to involve the donal expansion of a pre-malignant cell through a series of pheno-typic changes was explained by the initiation/promotion model of cardnogenesis. Unrepaired DNA lesions, acting as substrates for mutations in dividing cells, were speculated to play a role in the initiation phase of cardnogenesis (and indirectly to the promotion phase if the lesions lead to significant cell killing, forcing “compensatory hyperplasia”). Inhibition of intercellular communication, either by cell removal, cell death, growth factors or chemical promoters, was speculated to allow the donal expansion of initiated cells to reach a “critical mass.” During that donal expansion of initiated cells, additional phenotypic changes were speculated to occur during cell replication by mutational and/or epigenetic events. Therefore, it was concluded, on the basis of this model, that conditions which prevented the inhibition of intercellular communication between normal cells and the initiated cell(s) contributed to the rate limiting step of cardnogenesis.Assuming the initiation and promotion model of cardnogenesis, the classical concepts of “thresholds” and “carcinogens” were viewed as grossly inadequate because they did not symbolically represent the known determinants of the complex carcinogenic process. Unless genetic, developmental stage, tissue, nutritional, stress, life style, as well as concurrent antagonists and/or synergists, factors are known, extrapolation about the potential carcinogenicity of a given chemical from molecular, in vitro or even in vivo experiments or epidemiological data would be extremely risky. It was concluded that, at this stage of our understanding of the mech-anism(s) of carcinogenesis, attempts to determine “thresholds” for “carcinogens” naively assume “carcinogens” are the single determinants for carcinogenesis, and that all chemicals which might influence the appearance of tumors act the same way.
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Affiliation(s)
- James E. Trosko
- Department of Pediatrics and Human Development Division of Human Genetics, Genetic Toxicology, Endocrinology and Oncology. Michigan State University
| | - Chia-cheng Chang
- Department of Pediatrics and Human Development Division of Human Genetics, Genetic Toxicology, Endocrinology and Oncology. Michigan State University
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Baldanzi G. Inhibition of diacylglycerol kinases as a physiological way to promote diacylglycerol signaling. Adv Biol Regul 2014; 55:39-49. [PMID: 24582387 DOI: 10.1016/j.jbior.2014.02.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2013] [Revised: 01/02/2014] [Accepted: 02/02/2014] [Indexed: 01/12/2023]
Abstract
Diacylglycerol is a key regulator of cell physiology, controlling the membrane recruitment and activation of signaling molecules. Accordingly, diacylglycerol generation and metabolism are strictly controlled, allowing for localized regulation of its concentration. While the increased production of diacylglycerol upon receptor triggering is well recognized, the modulation of diacylglycerol metabolism by diacylglycerol kinases (DGKs) is less characterized. Some agonists induce DGK activation and recruitment to the plasma membrane, promoting diacylglycerol metabolism to phosphatidic acid. Conversely, several reports indicate that signaling pathways that selectively inhibits DGK isoforms can enhance cellular diacylglycerol levels and signal transduction. For example, the impairment of DGKθ activity by RhoA binding to the catalytic domain represents a conserved mechanism controlling diacylglycerol signaling from Caenorhabditis elegans motoneurons to mammalian hepatocytes. Similarly, DGKα activity is inhibited in lymphocytes by TCR signaling, thus contributing to a rise in diacylglycerol concentration for downstream signaling. Finally, DGKμ activity is inhibited by ischemia-reperfusion-generated reactive oxygen species in airway endothelial cells, promoting diacylglycerol-mediated ion channel opening and edema. In those systems, DGKs provide a gatekeeper function by blunting diacylglycerol levels or possibly establishing permissive domains for diacylglycerol signaling. In this review, I discuss the possible general relevance of DGK inhibition to enhanced diacylglycerol signaling.
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Affiliation(s)
- Gianluca Baldanzi
- University "A. Avogadro" del Piemonte Orientale, Department of Translational Medicine, via Solaroli 17, 28100 Novara, Italy.
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3
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Abstract
The last 10 years have seen a significant expansion in the scope of attempts to manipulate the growth of animals (Buttery, Lindsay and Haynes, 1986). The expansion of interest has been driven by a number of factors, both economic and theoretical. At the economic level the need to develop energetically and economically efficient strategies of animal production has been coupled with a renewed awareness of the implications for human health of excessive intakes of saturated fats. Emphasis then has switched from the maximization of weight gain as an end in itself towards a need to promote protein deposition at any given intake and, at the same time, to reduce the fat content of meat and meat products. These twin objectives might be achieved by one of three strategies: the promotion of protein deposition alone, because at any given rate of weight gain this will tend to minimize the rate of fat deposition (the so-called repartitioning effect); the reduction of fat gain (an approach that has received particularly close attention by those concerned primarily with human obesity); or ideally the simultaneous promotion of protein accretion and depression of that of fat.
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Sivak A. An evaluation of assay procedures for detection of tumor promotors. ACTA PHARMACOLOGICA ET TOXICOLOGICA 2009; 55 Suppl 2:69-88. [PMID: 6385623 DOI: 10.1111/j.1600-0773.1984.tb02483.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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5
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Abstract
An increasing body of evidence indicates that the response to genotoxic agents such as radiation or drugs is a group phenomenon, rather than the summed response of individual independent cells to injury. Thus, a complex contagion-like response may spread beyond the initial impact of an agent to enlarge its effect. This indirect effect, termed "Bystander Effect," is multifaceted and may play a significant role in the therapy of tumors and in carcinogenesis. A better understanding of this phenomenon is needed in order to modulate treatment protocols to therapeutic advantage and to provide more rational guidelines for the evaluation of environmental hazards.
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Affiliation(s)
- B Djordjevic
- Department of Radiation Oncology, Health Science Center at Brooklyn, State University of New York, Brooklyn, NY 11203, USA
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Jahan I, Iijima M, Kondo T, Namba M. Effects of okadaic acid on cell growth, anchorage-independent growth, and co-cultures of normal (KMS-6), immortalized (KMST-6), and neoplastically transformed (KMST-6T and KMST-6/RAS) human fibroblasts. J Cancer Res Clin Oncol 1996; 122:249-53. [PMID: 8601579 DOI: 10.1007/bf01209654] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The effects of okadaic acid (OA) on normal human (KMS-6), its immortalized (KMST-6) and neoplastically transformed (KMST-6T and KMST-6/RAS) cells were investigated as a model of two stage carcinogenesis. The presence of OA inhibited cell growth of the normal and immortalized cells but not that of the neoplastic KMST-6T cells. In contrast, cell growth of the other neoplastic KMST-6/RAS cells transformed with the Ha-ras oncogene was inhibited by OA. OA enhanced colony formation of KMST-6T cells in soft agar, but it suppressed that of KMST-6/RAS cells. Co-cultures of KMST-6T cells with normal KMS-6 cells showed an increase in focus formation of KMST-6T cells in the presence of OA, whereas focus formation of KMST-6/RAS cells decreased. These results indicate that OA has growth-promoting effects on certain types of transformed human cells.
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Affiliation(s)
- I Jahan
- Department of Cell Biology, Institute of Cellular and Molecular Biology, Okayama Univeristy Medical School, Japan
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Matthews EJ. Transformation of BALB/c-3T3 cells: I. Investigation of experimental parameters that influence detection of spontaneous transformation. ENVIRONMENTAL HEALTH PERSPECTIVES 1993; 101 Suppl 2:277-91. [PMID: 8243398 PMCID: PMC1519958 DOI: 10.1289/ehp.93101s2277] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
The frequency of spontaneous morphological transformation is an important variable in measuring chemical-induced transformation in BALB/c-3T3 clone A-31-1-13 cell cultures. Data from 110 experiments, which included benzo[a]pyrene control groups and other chemical treatment groups, were analyzed for factors that influenced spontaneous transformation. Spontaneous transformants demonstrated a continuum of morphological variants (type I, II, and III foci) that fit a normal distribution if converted to log10. The magnitude of transformation depended on the ampule of cryopreserved cells and the serum lot. Although the average frequency was approximately 0.71 x 10(-6) (type III foci/cell that survived and proliferated to confluence), the absolute number of foci/vessel increased in proportion to the surface area of the culture vessel. Thus, the frequency of spontaneous transformation was directly related to the cumulative number of mitoses that occurred in forming the contact-inhibited monolayer. These data are consistent with a hypothesis that spontaneous transformation in BALB/c-3T3 cells is a mutational event or some other single-step phenomenon.
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Affiliation(s)
- E J Matthews
- Center for Food Safety and Applied Nutrition, Food and Drug Administration, Washington, DC 20204
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Matthews EJ. Transformation of BALB/c-3T3 cells: II. Investigation of experimental parameters that influence detection of benzo[a]pyrene-induced transformation. ENVIRONMENTAL HEALTH PERSPECTIVES 1993; 101 Suppl 2:293-310. [PMID: 8243399 PMCID: PMC1519957 DOI: 10.1289/ehp.93101s2293] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Benzo[a]pyrene (BaP) induced significant morphological transformation of clone A31-1-13 BALB/c-3T3 cells without exogenous activation. Therefore, BaP was selected as a model to determine the internal consistency of detection of chemical-induced transformation. BaP induced a continuum of type I-III foci of different sizes, and the ratio of type I-III to type III foci/vessel was usually about 2-fold. The major finding was that BaP induced highly significant transformation responses, and the magnitude of these responses were inversely correlated with the cytotoxicity of the treatment doses. Thus, the induction of BaP-induced transformation behaved as though it was caused by a mutational event. Variability among responses were shown to depend on the serum lot and the cryopreserved ampule of cells. In addition, experiments with low spontaneous transformation responses had an impaired ability to detect BaP; however, experiments with high or normal spontaneous responses had a normal ability to detect BaP. Because the expression of BaP-induced transformation depended on both the cytotoxicity of the treatment and the cumulative number of mitoses, the frequency of BaP-induced transformation should be reported as the number of foci/vessel, but not expressed as the number of foci/viable cell surviving the chemical treatment. These conclusions are important because the same 110 experiments described in this report were also used to evaluate the transformation responses of many different carcinogenic and noncarcinogenic chemicals. These data are being reported separately.
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Affiliation(s)
- E J Matthews
- Center for Food Safety and Applied Nutrition, Food and Drug Administration, Washington, DC 20204
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Fitzgerald DJ, Yamasaki H. Tumor promotion: models and assay systems. TERATOGENESIS, CARCINOGENESIS, AND MUTAGENESIS 1990; 10:89-102. [PMID: 1973858 DOI: 10.1002/tcm.1770100205] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Tumor promotion is defined operationally from two-stage models of experimental carcinogenesis. It is, therefore, in a strict sense, possible to identify tumor promoters only from such models. The development and use of in vitro two-stage cell transformation assays was a logical extension toward in vitro short-term testing for tumor promoters. Another approach is to apply mechanistic knowledge of the tumor promotion process in developing end points for such assays. In this context, we have been examining the role of blocked gap-junctional intercellular communication (GJIC) in tumor promotion, using in vitro and in vivo systems. Many promoters have been shown to block GJIC in vitro; our studies support the idea that inhibition of GJIC does play an important role in the promotion stage of BALB/c 3T3 cell transformation. In animal studies, we have shown that the rat liver tumor promoter phenobarbital can decrease the level of expression of the 32 Kd gap junction protein gene specifically in liver upon systemic exposure in rats. Further examination of the role of GJIC in tumor promotion is indeed warranted. Also, deployment of in vitro GJIC and transformation assay systems should provide useful short-term tests for detecting tumor promoting activity of environmental chemicals.
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Affiliation(s)
- D J Fitzgerald
- Programme of Multistage Carcinogenesis, International Agency for Research on Cancer, Lyon, France
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Abstract
Tumor-promoting phorbol ester derivatives are known to stimulate as well as inhibit the cell cycle traverse of many kinds of cells, but it is not known whether or how these effects are related to tumor promotion. It is shown here that the potency of the phorbol diester PMA (phorbol myristate acetate) to cause a delay of cell division depends on the cell cycle position at the beginning of exposure to the PMA. Quiescent human fibroblasts were stimulated with epidermal growth factor, and PMA was added to the cultures at different times after stimulation. The later PMA was added, the stronger was the mitotic delay it caused. This means that cells which become exposed while they are in an early stage of the cycle are less effectively delayed and reach mitosis earlier than those for which exposure begins at a later stage of the cycle. The data indicate that PMA is actually able to reverse the order in which the cells of a normally growing population divide. In organized tissues this could disturb the intercellular communication which may be linked to the relative cell cycle positions of neighboring cells.
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Affiliation(s)
- R M Böhmer
- Ludwig Institute for Cancer Research, Melbourne Tumour Biology Branch, Victoria, Australia
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11
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Affiliation(s)
- A Balmain
- Beatson Institute for Cancer Research, Garscube Estate, Bearsden, Glkasgow, Scotland
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Herschman HR, Brankow DW. Ultraviolet irradiation transforms C3H10T1/2 cells to a unique, suppressible phenotype. Science 1986; 234:1385-8. [PMID: 3787250 DOI: 10.1126/science.3787250] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Transformation of C3H10T1/2 cells by exposure to ultraviolet (UV) irradiation followed by tetradecanoyl phorbol acetate (TPA) has been used as a model of two-stage carcinogenesis. However, cells cloned from UV-TPA-induced foci (UV-TDTx cells) had a unique phenotype. Cloned UV-TDTx cells appeared transformed in pure culture but were unable to form foci when cocultured with C3H10T1/2 cells. However, in the presence of TPA, UV-TDTx cells form foci in mixed culture with C3H10T1/2 cells. This phenotype was the only one observed for UV-TPA transformants. These data suggest that communal suppression of cell division is a discrete phenomenon that must be overcome as one step in the multistage process of transformation, and this protocol permits the routine isolation of transformed cells responsive to density-dependent growth suppression.
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Tran PL, Sala M, Chouroulinkov I. In vitro and in vivo activity of 12-O-3-N-dansylamino TPA. EUROPEAN JOURNAL OF CANCER & CLINICAL ONCOLOGY 1986; 22:1157-63. [PMID: 3816908 DOI: 10.1016/0277-5379(86)90316-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Dansyl-TPA, a fluorescent TPA analogue, which is a label with a high affinity for C3H/10T1/2 cells and induces 3H-choline release from these cells (Tran et al. Nouv. J. Chim 1984, 8, 751-757), has been studied for in vitro promoting activity in the same cell line initiated by a carcinogen MNNG and in vivo short-term mouse skin tests. In vitro, dansyl-TPA expresses transforming effect in its own (without MNNG pretreatment) as well as increases the production of transformed foci in MNNG-treated cells. In in vivo skin tests, dansyl-TPA displays lower effects than TPA on mouse skin. These results indicate a low promoting potential of dansyl-TPA.
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Fey EG, Penman S. Tumor promoters induce a specific morphological signature in the nuclear matrix-intermediate filament scaffold of Madin-Darby canine kidney (MDCK) cell colonies. Proc Natl Acad Sci U S A 1984; 81:4409-13. [PMID: 6431407 PMCID: PMC345599 DOI: 10.1073/pnas.81.14.4409] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Tumor promoters such as phorbol 12-tetradecanoate 13-acetate (TPA), mezerein, teleocidin, aplysiatoxin, and benzoyl peroxide, although structurally unrelated, induce similar, profound changes in morphology in differentiated epithelial Madin-Darby canine kidney (MDCK) cell colonies. The alteration is evident in the organization of intermediate filaments in intact cells and in whole mounts of the nuclear matrix-intermediate filament (NM-IF) scaffold of the epithelial sheet. This substructure, obtained by salt extraction of the cytoskeletal framework, represents only 5% of the total cell protein but contains all of the intermediate filaments, nuclear matrix, and desmosomal core proteins arranged essentially as in the intact cell. The NM-IF is profoundly reorganized after exposure to TPA and retains the morphological changes observed in intact cells. These include bundling of the intermediate filaments, disruption of cell-cell borders, and marked deformation of the polygonal geometry of epithelia. Thus, TPA and all other complete or second-stage tumor promoters examined have a characteristic morphological signature that is not induced by mitogens, metabolic inhibitors, or agents known to disrupt microtubules or microfilaments. This signature, characteristic of tumor promoters, occurs in the absence of both protein and RNA synthesis. These results suggest that this response is prior to and independent of other biochemical markers for tumor promoters. Of the major filament systems, the cytokeratin network is implicated as an early or possibly primary site of tumor-promoter action because characteristics of the promoted cytoskeletal signature are observed in epithelial colonies after prior exposure to colchicine or cytochalasin D. Despite the massive reorganization of cytoskeletal morphology induced by TPA, the distribution of prelabeled proteins into structural fractions (i.e., cytoskeletal, chromatin, and the NM-IF) remains essentially unchanged. The sensitivity and specificity of the epithelial cell response suggest its possible use as a screen for promoting compounds.
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Grotendorst GR. Alteration of the chemotactic response of NIH/3T3 cells to PDGF by growth factors, transformation, and tumor promoters. Cell 1984; 36:279-85. [PMID: 6607119 DOI: 10.1016/0092-8674(84)90221-6] [Citation(s) in RCA: 105] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The platelet-derived growth factor (PDGF) is a potent chemoattractant for cells that respond to PDGF as a mitogen. The chemotactic response of these cells to PDGF is inversely related to their rate of proliferation, with quiescent cells exhibiting a 25-fold greater chemotactic response than exponentially growing cells. Factors that stimulate the growth of quiescent cells (EGF, FGF, PDGF, and serum) decrease the cells' migratory response to PDGF but not to fibronectin, suggesting that the decreased migration is not due to a general paralysis of cell motility. Transformed lines of NIH/3T3 cells lose their ability to respond to PDGF as a chemoattractant but can still migrate in response to fibronectin. Similarly, after treatment of 3T3 cells with the tumor-promoter phorbol myristate acetate, which induces a transformation-like phenotype, the cells no longer respond to PDGF as a chemoattractant but retain their migratory response to fibronectin. Thus it appears that the growth state of the cells can alter their migratory response to PDGF. These data suggest that growth factors, transformation, and tumor promoters specifically alter the cells' ability to respond to the PDGF-mediated chemotactic signal. It appears that both transformation and tumor promoters accomplish this by altering PDGF-binding to the cell surface.
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Trosko JE, Chang CC, Medcalf A. Mechanisms of tumor promotion: potential role of intercellular communication. Cancer Invest 1983; 1:511-26. [PMID: 6365277 DOI: 10.3109/07357908309020276] [Citation(s) in RCA: 91] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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Bohrman JS. Identification and assessment of tumor-promoting and cocarcinogenic agents: state-of-the-art in vitro methods. Crit Rev Toxicol 1983; 11:121-67. [PMID: 6340968 DOI: 10.3109/10408448309089850] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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Sivak A. International Commission for Protection against Environmental Mutagens and Carcinogens ICPEMC working paper 2/8: An evaluation of assay procedures for detection of tumor promotors. Mutat Res 1982; 98:377-87. [PMID: 7050698 DOI: 10.1016/0165-1110(82)90041-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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Kopelovich L. Hereditary adenomatosis of the colon and rectum: relevance to cancer promotion and cancer control in humans. CANCER GENETICS AND CYTOGENETICS 1982; 5:333-52. [PMID: 7046911 DOI: 10.1016/0165-4608(82)90099-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
We propose that SF derived from normal-appearing biopsies of ACR gene carriers exist in an initiated state as the result of a dominant mutation. Based on our studies with the ACR cell system, we further suggest that, although an initiated state is essential to cancer development, not all initiated cells necessarily develop into cancerous cells. The genetic makeup of an initiated cell has been established through linkage between abnormal phenotypic markers and pedigree profiles and through cell hybridization, including initial analysis of gene products. We believe that it is consistent with an autosomal dominant trait. In contrast, cells from patients who are homozygous for chromosomal breakage syndromes, including those with xeroderma pigmentosum, represent an experiment of nature which presumably underlies factors associated with cancer promotion in humans. We have demonstrated that ACR cells can be differentially transformed by oncogenic viruses, a carcinogen (MNNG), and gamma-ray irradiation, and that they can proliferate in vitro after exposure to a tumor promoter (TPA. This simple experimental model provides a novel system for the study of tumor promotion in vitro. We further suggest that, through the use of TPA, various stages associated with cancer development in humans, i.e., initiation through promotion and progression, can be identified in vitro. Attempts to apply these results in vivo are currently in progress. The apparent susceptibility of ACR cells to further transformation by oncogenic viruses and chemical and physical agents indicates that genetic information residing within these cells, probably in the form of a relatively limited and specific number of DNA sequences associated with the ACR mutation, renders them more sensitive to these three distinct classes of carcinogens. We submit that, through our tests on SF, and ACR gene carriers within recognized ACR clusters can be diagnosed at present with sufficient certainty to warrant immediate action. In addition, it seems that the time has arrived for a major undertaking to screen for persons who are likely to be at increased risk of cancer, perhaps through walk-in clinics. An underlying assumption in these studies is that predisposition to cancer, in general, is associated with an autosomal dominant trait in obligatory heterozygote gene carriers.
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Lin JC, Smith MC, Pagano JS. Effects of 12-O-tetradecanoyl-phorbol-13-acetate on cell proliferation and Epstein-Barr virus DNA replication. Virology 1982; 117:186-94. [PMID: 6278735 DOI: 10.1016/0042-6822(82)90518-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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Bertram JS, Bertram BB, Janik P. Inhibition of neoplastic cell growth by quiescent cells is mediated by serum concentration and cAMP phosphodiesterase inhibitors. J Cell Biochem 1982; 18:515-38. [PMID: 6282911 DOI: 10.1002/jcb.1982.240180412] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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22
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Trosko JE, Chang CC, Netzloff M. The role of inhibited cell-cell communication in teratogenesis. TERATOGENESIS, CARCINOGENESIS, AND MUTAGENESIS 1982; 2:31-45. [PMID: 6122278 DOI: 10.1002/1520-6866(1990)2:1<31::aid-tcm1770020105>3.0.co;2-2] [Citation(s) in RCA: 57] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
A mechanistic link between teratogenesis and carcinogenesis has been suggested by a wide variety of scientific observations. This report attempts to provide a theoretical explanation for one of the several possible mechanisms which might be shared during carcinogenesis and teratogenesis. The initiation and promotion concept of carcinogenesis was briefly reviewed and the role of intercellular communication during the complex tumor promotion phase was discussed. Inhibition of intercellular communication by a wide variety of physical, chemical and biological factors was speculated to disrupt the regulation of proliferation and differentiation in stem cells. Chemicals, which interfered with intercellular communication during early organogenesis, have the potential of being teratogens, while if they are present in the developed, initiated organisms have the potential of being tumor promoters. Evidence was presented showing that known tumor promoters which inhibited intercellular communication also had been shown to be teratogens. It was concluded that in vitro assays, designed to measure intercellular communication, although having known limitations, might be used as an in vitro means to screen for potential teratogens.
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Påhlman S, Odelstad L, Larsson E, Grotte G, Nilsson K. Phenotypic changes of human neuroblastoma cells in culture induced by 12-O-tetradecanoyl-phorbol-13-acetate. Int J Cancer 1981; 28:583-9. [PMID: 7309295 DOI: 10.1002/ijc.2910280509] [Citation(s) in RCA: 195] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
SK-N-SH and SH-SY5Y human neuroblastoma cells treated by 12-)-tetradecanoyl-phorbol-13-acetate(TPA) express morphological and biochemical changes, which indicate that differentiation towards more mature cells has occurred. The most prominent morphological changes were the development in 40-60% of the cells of cell-surface projections longer than 50 micrometers and cytoplasmic neurosecretory granules demonstrated by electron microscopy. At the biochemical level, TPA induced a two-fold increase in the relative activity of neuron-specific enolase and 30- to 40-fold increase in noradrenaline and adrenaline concentrations. A decrease in proliferation rate of TPA-treated cells was observed. The biological effects of TPA were slightly potentiated by nerve growth factor.
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Colburn NH, Wendel EJ, Abruzzo G. Dissociation of mitogenesis and late-stage promotion of tumor cell phenotype by phorbol esters: mitogen-resistant variants are sensitive to promotion. Proc Natl Acad Sci U S A 1981; 78:6912-6. [PMID: 6947266 PMCID: PMC349162 DOI: 10.1073/pnas.78.11.6912] [Citation(s) in RCA: 153] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
The JB-6 mouse epidermal cell line has been used as a model system for studying the mechanism of late-stage promoter-dependent preneoplastic progression. The studies reported here are concerned with determining whether there is a requirement for mitogenic stimulation in promotion of anchorage independence and tumorigenicity in JB-6 cells. Such a requirement would predict that variants selected for 12-O-tetradecanoylphorbol 13-acetate (TPA) mitogen resistance would also be promotion resistant. Promotion-responsive cell lines have been selected for resistance to TPA-induced mitogenic stimulation at plateau density by cotreatment with colchicine and removal of mitogen-responsive colchicine-detached cells. The selected TPA-resistant population of cells showed a mitogenic response that was diminished by a factor of four but showed no diminution in the promotion-of-anchorage-independence response to TPA. Mitogen-resistant clonal lines derived from the selected population fell into three phenotypic classes when assayed in soft agar: (i) anchorage-independent transformants; (ii) variants resistant to promotion of anchorage independence by TPA; and (iii) variants sensitive to promotion by TPA. The existence of the latter class (i.e., the mitogen-resistant promotable variants) indicates a lack of obligatory causal relationship between TPa-induced mitogenesis and late-stage promotion and, thereby suggests that the two events can be dissociated.
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Enomoto T, Sasaki Y, Shiba Y, Kanno Y, Yamasaki H. Tumor promoters cause a rapid and reversible inhibition of the formation and maintenance of electrical cell coupling in culture. Proc Natl Acad Sci U S A 1981; 78:5628-32. [PMID: 6946500 PMCID: PMC348809 DOI: 10.1073/pnas.78.9.5628] [Citation(s) in RCA: 74] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
The effect of tumor promoters on electrical coupling between human FL cells was investigated with a microelectrode technique. When a low concentration (100 ng/ml) of 12-O-tetradecanoylphorbol 13-acetate (TPA) was added to culture medium, only 6% of the cells showed electrical coupling after 5 hr, whereas in control medium more than 90% of the cells were coupled. In the presence of TPA, cell coupling remained suppressed for at least another 19 hr. When TPA was washed out from the culture medium, the cells commenced electrical coupling: 90% of the cells were coupled within 4 hr of the removal of TPA, a rate very similar to that of nontreated control cells. Therefore, TPA-mediated inhibition of cell coupling is reversible. When TPA was added to a culture in which more than 90% of the cells had already established electrical coupling, the percentage of coupled cells decreased to 6% within 8 hr, indicating that TPA can also diminish already established cell coupling. Inhibition of cell coupling also was achieved with other mouse skin tumor promoters--phorbol 12,13-didecanoate, ingenol dibenzoate, and mezerein--whereas nonpromoting derivatives--phorbol and 4 alpha-phorbol 12,13-didecanoate-showed no effect. None of these compounds changed the membrane potential, membrane resistance, or growth rate of FL cells. Thus, it appears that TPA and structurally-related tumor promoters specifically disturb the formation or function, or both, of cell-cell junctions, without significantly affecting the general properties of the surface membrane or the growth of FL cells.
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Blumberg PM. In vitro studies on the mode of action of the phorbol esters, potent tumor promoters, part 2. Crit Rev Toxicol 1981; 8:199-234. [PMID: 7018838 DOI: 10.3109/10408448109109658] [Citation(s) in RCA: 140] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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Fisher PB, Dorsch-Häsler K, Weinstein IB, Ginsberg HS. Interactions between initiating chemical carcinogens, tumor promoters, and adenovirus in cell transformation. TERATOGENESIS, CARCINOGENESIS, AND MUTAGENESIS 1981; 1:245-57. [PMID: 6119815 DOI: 10.1002/tcm.1770010302] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Cell culture systems that respond to the combined action of initiating chemical carcinogens, tumor promoters, and transforming viruses represent useful model systems for studying the complex multifactor nature of the carcinogenic process. We have utilized both secondary rat embryo (2 degrees RE) and a clonal population of established Fischer rat embryo (CREF) cells to study the effect of multiple agents on the process of adenovirus transformation. In the present review we summarize our investigations on the effects of polycyclic aromatic hydrocarbons, tumor promoters, a bee venom polypeptide-melittin (MEL), and the polypeptide hormone epidermal growth factor (EGF) on transformation of rat embryo cells by a temperature-sensitive mutant of human adenovirus type 5 (H5ts125). We also describe the effect of tumor promoters on the progression of the transformed phenotype, ie the temporal acquisition of anchorage-independent growth in adenovirus-transformed clones and the ability of MEL and EGF to elicit effects similar to those of tumor promoters in adenovirus-transformed cells.
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Shiba Y. Modulatory action of 12-O-tetradecanoylphorbol-13-acetate on bud production inHydra. ACTA ACUST UNITED AC 1981; 190:305-307. [DOI: 10.1007/bf00863266] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/1981] [Accepted: 12/02/1981] [Indexed: 12/01/2022]
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Trosko JE, Chang CC. The Role of Radiation and Chemicals in the Induction of Mutations and Epigenetic Changes during Carcinogenesis. ACTA ACUST UNITED AC 1981. [DOI: 10.1016/b978-0-12-035409-2.50006-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/12/2023]
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30
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Zbinden G, Maier P, Alder S. Granuloma pouch assay. III. Enhancement of the carcinogenic effect of N-methyl-N'-nitro-N-nitrosoguanidine. Arch Toxicol 1980; 45:227-32. [PMID: 7458672 DOI: 10.1007/bf02419003] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Proliferation of granulation tissue on the inside of a subcutaneous (s.c.) air pocket was induced in rats by administration of 0.5 ml of 0.25% croton oil (granuloma pouch). Two days after induction of the granuloma, i.e., during the period of maximal cell growth, a single dose of 0.6 mg or 0.1 mg N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) was administered into the pouch. Fibrosarcomas of various histopathological types developed in 87% of the rats receiving the high dose and in 64% of the low dose animals. The mean latency period was 47.5 and 51.7 weeks respectively. Only one local sarcoma developed in rats treated with 0.6 mg MNNG by the s.c. route, and no tumors were observed in the groups treated with 0.1 mg s.c. The appearance of local sarcomas in the granuloma pouch tissue is correlated with previously reported frequency of point mutations (OUAR and HGPRT-) induced in granuloma fibroblasts with the same doses of MNNG. Possible mechanisms explaining the marked enhancement of the carcinogenic effect of MNNG in the granuloma pouch assay are discussed.
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31
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Trosko JE, Chang CC. An integrative hypothesis linking cancer, diabetes and atherosclerosis: the role of mutations and epigenetic changes. Med Hypotheses 1980; 6:455-68. [PMID: 7412638 DOI: 10.1016/0306-9877(80)90098-5] [Citation(s) in RCA: 73] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
It appears that the disease states of cancer, altherosclerosis and diabetes might share a common etiology. These chronic diseases appear to be multi-staged in their progression, with genetic, nutritional, psycho-social, environmental and viral factors influencing their appearance. We offered a hypothesis (a "mutation theory of disease"), stating that these diseases can be described by initiation and promotion phases; initiation being the result of the production of mutated cells after unrepaired damaged DNA is replicated; promotion being the selective proliferation of the initiated cells to form clones of mutated cells. It was further postulated that promotion affects cell proliferation by altering a membrane-Ca++ regulatory system. Depending on the nature of the mutation in the clone of cells, specific disease states would result. The roles of radiations, chemicals, viruses, genes, nutrition and psycho-social stress were related to either the initiation (mutation production) or the promotion (cell proliferation) phase of these diseases.
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Dulbecco R, Bologna M, Unger M. Control of differentiation of a mammary cell line by lipids. Proc Natl Acad Sci U S A 1980; 77:1551-5. [PMID: 6929508 PMCID: PMC348534 DOI: 10.1073/pnas.77.3.1551] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
A rat mammary cell line (LA7) undergoes spontaneous differentiation into domes due to production of specific inducers by the cells. Some of these inducers may be lipids, and we show that lipids regulate this differentiation as both inducers and inhibitors. One inhibitor is the tumor promoter tetradecanoyl-13 phorbol 12-acetate. The inducers are saturated fatty acids of two groups: butyric acid and acids with chain lengths from C13 to C16, especially myristic acid (C14). Other inducers are myristoyl and palmitoyl lysolecithins, myristic acid methyl ester, and two cationic detergents with a tetradecenyl chain. We propose that the lipids with a C14-C16 alkyl chain affect differentiation by recognition specific receptors through their alkyl chains and that the effects obtained depend on the head groups. These lipids may be physiological regulators in the mammary gland.
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Gottesman MM, Sobel ME. Tumor promoters and Kirsten sarcoma virus increase synthesis of a secreted glycoprotein by regulating levels of translatable mRNA. Cell 1980; 19:449-55. [PMID: 6244111 DOI: 10.1016/0092-8674(80)90519-x] [Citation(s) in RCA: 120] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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34
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Rochette-Egly C, Chouroulinkov I, Castagna M. Early inhibition of thymidine uptake and stimulation of cell proliferation in rat embryo fibroblasts treated with tumor-promoting 12-O-tetradecanoyl-phorbol-13-acetate. Eur J Cancer 1980; 16:229-38. [PMID: 7371680 DOI: 10.1016/0014-2964(80)90155-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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The Effect of 12-0-Tetradecanoyl-Phorbol-13-Acetate (TPA) on Cell Transformation by Simian Virus 40 Mutants. ACTA ACUST UNITED AC 1980. [DOI: 10.1007/978-94-009-9104-0_30] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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37
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Yotti LP, Chang CC, Trosko JE. Elimination of metabolic cooperation in Chinese hamster cells by a tumor promoter. Science 1979; 206:1089-91. [PMID: 493994 DOI: 10.1126/science.493994] [Citation(s) in RCA: 442] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Wild-type Chinese hamster V79 cells (6-thioguanine-sensitive) reduce the recovery of 6-thioguanine-resistant cells when they are cultured together at high densities, through a form of intercellular communication (metabolic cooperation). Cooperation is inhibited by 12-O-tetradecanoyl phorbol-13-acetate, rescuing the 6-thioguanine-resistant cells. These results may be useful in the study of an aspect of the mechanism of tumor promotion and in assaying for promoters.
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Lee LS, Weinstein IB. Membrane effects of tumor promoters: stimulation of sugar uptake in mammalian cell cultures. J Cell Physiol 1979; 99:451-60. [PMID: 457799 DOI: 10.1002/jcp.1040990319] [Citation(s) in RCA: 86] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Phorbol esters stimulate 2-deoxy-D-glucose (DG) uptake in rodent and human cell cultures. The potent tumor promoting agent, 12-0-tetradecanoyl phorbol-13 acetate (TPA), induces a 12-fold stimulation in confluent 3T3 cells and 2.5-fold stimulation in HeLa cells. When a series of macrocyclic deterpenes are assayed, their relative potencies in stimulating DG uptake in 3T3 cells correlate with other known biologic effects of these compounds. On a molar basis, TPA is a much more potent stimulator of DG transport than insulin or epidermal growth factor. In HeLa cells, the ED50 value of the TPA effect is 0.2 nM. The increase in DG uptake occurs immediately after the addition of TPA, reaches a maximum at 90 minutes, persists for at least three hours after removal of TPA from the medium, and is temperature dependent. The stimulation is not inhibited by cycloheximide or actinomycin D. As in control cells, DG uptake in TPA treated cells is inhibited by p-hydroxymercuribenzoate, phyloridzin, cytochalasin B, and dexamethasone. Although the precise mechanism is not known, evidence is presented that the TPA stimulation of DG uptake is due to enhanced transport of the sugar rather than to effects on intracellular metabolism. The enhanced transport may be secondary to a more generalized change in membrane structure.
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40
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Castagna M, Rochette-Egly C, Rosenfeld C, Mishal Z. Altered lipid microviscosity in lymphoblastoid cells treated with 12-O-tetradecanoyl phorbol 13-acetate, a tumor promoter. FEBS Lett 1979; 100:62-6. [PMID: 437111 DOI: 10.1016/0014-5793(79)81131-x] [Citation(s) in RCA: 39] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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Weinstein IB, Lee LS, Fisher PB, Mufson A, Yamasaki H. Action of phorbol esters in cell culture: mimicry of transformation, altered differentiation, and effects on cell membranes. JOURNAL OF SUPRAMOLECULAR STRUCTURE 1979; 12:195-208. [PMID: 397370 DOI: 10.1002/jss.400120206] [Citation(s) in RCA: 148] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The carcinogenic process is usually multifactor in its causation and multistep in its evolution. It is likely that entirely different molecular mechanisms underlie the many steps in this process. In contrast to initiating carcinogens, the action of the tumor-promoting phorbol esters does not appear to involve covalent binding to cellular DNA and they are not mutagenic. Recent studies in cell culture have revealed two interesting biologic effects of the phorbol esters and related macrocyclic plant diterpenes. The first is that at nanomolar concentrations they induce several changes that resemble those seen in cells transformed by chemical carcinogens or tumor viruses. These include altered morphology and increased saturation density, altered cell surface fucose-glycopeptides, decrease in the LETS protein, increased transport of deoxyglucose, and increased levels of plasminogen activator and ornithine decarboxylase. In transformed cells exposed to phorbol esters the expression of these features is further accentuated. Phorbol esters do not induce normal cells to grow in agar but they do enhance the growth in agar of certain transformed cells. The second effect of the phorbol esters is inhibition of terminal differentiation. This effect extends to a variety of programs of differentiation and is reversible when the agent is removed. With certain cell culture systems induction of differentiation, rather than inhibition, is observed. Both the transformation mimetic and the differentiation effects are exerted by plant diterpenes that have tumor-promoting activity but not by congeners that lack such activity. The primary target of phorbol esters appears to be the cell membrane. Early membrane-related effects include enhanced uptake of 2-deoxyglucose and other nutrients, altered cell adhesion, induction of arachidonic acid release and prostaglandin synthesis, inhibition of the binding of epidermal growth factor to cell surface receptors, altered lipid metabolism, and modifications in the activities of other cell surface receptors. A model of "two stage" carcinogenesis encompassing the known molecular and cellular effects of initiating carcinogens and tumor promoters is presented. According to this model, initiating carcinogens induce stable alterations in the cellular genome but these are not manifested until tumor promoters modulate programs of gene expression and induce the clonal outgrowth of the initiated cell.
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Miskin R, Easton TG, Maelicke A, Reich E. Metabolism of acetylcholine receptor in chick embryo muscle cells: effects of RSV and PMA. Cell 1978; 15:1287-300. [PMID: 215321 DOI: 10.1016/0092-8674(78)90054-5] [Citation(s) in RCA: 40] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
We have investigated some aspects of the metabolism of the integral membrane protein acetylcholine receptor (AChR) in normal and transformed cultures of chick embryo muscle cells. Turnover of AChR in control muscle cell cultures was compared with turnover in cultures infected and transformed by a temperature-sensitive mutant of Rous sarcoma virus (RSV) and with cultures treated with the tumor promoter phorbol myristate acetate (PMA). The parameters of AChR metabolism were estimated using 125I-alpha-bungarotoxin as a stoichiometric high affinity ligand for the AChR. We found that both RSV transformation and PMA increased the rate of degradation and decreased the rate of synthesis of AChR. The consequent reduction in steady state receptor levels suggests that oncogenic transformation and tumor promoter significantly alter the metabolism of cell surface membranes. We also observed that parameters of AChR metabolism in control cultures changed systematically in a pattern which depended upon the age of the culture as well as the use of embryo extract or fetal bovine serum as medium supplements. The muscle cell system allows quantitative measurement of an integral membrane protein and its metabolism, and may serve as a more general model for alterations in membrane and surface receptor metabolism associated with the transformed state.
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Todaro GJ, De Larco JE, Sporn MB. Retinoids block phenotypic cell transformation produced by sarcoma growth factor. Nature 1978; 276:272-4. [PMID: 213728 DOI: 10.1038/276272a0] [Citation(s) in RCA: 98] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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45
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Ishii DN, Fibach E, Yamasaki H, Weinstein IB. Tumor promoters inhibit morphological differentiation in cultured mouse neuroblastoma cells. Science 1978; 200:556-9. [PMID: 644318 DOI: 10.1126/science.644318] [Citation(s) in RCA: 90] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
When added to mouse neuroblastoma cultures, the potent tumor promoter 12-O-tetradecanoyl-phorbol-13-acetate (TPA) inhibits spontaneous neurite formation as well as that induced in response to serum deprivation, prostaglandin E1, 5-bromo-2'-deoxyuridine, and papaverine. Other tumor-promoting macrocyclic plant diterpenes also inhibit neurite formation, whereas nonpromoting diterpenes do not. Inhibition by TPA was reversible and was unrelated to toxicity.
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Sivak A. Induction of cell division in BALB/c-3T3 cells by phorbol myristate acetate or bovine serum: effects of inhibitors of cyclic AMP phosphodiesterase and Na+-K+-ATPase. IN VITRO 1977; 13:337-43. [PMID: 195894 DOI: 10.1007/bf02615093] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Cell division is induced in stationary cultures of BALB/c-3T3 mouse embryo cells without renewal of medium by addition of the tumor promoter, phorbol myristate acetate (PMA), or bovine serum. The addition of dbcAMP (10(-3) M) or other inhibitors of cAMP phosphodiesterase, papaverine (6.7 X 10(-6) M), Persantin (5 X 10(-5) M) or RO-20-1724 (10(-4) M), prevents cell replication induced by PMA or serum. In contrast, ouabain (10(-4) M) and N,N'-dicyclohexylcarbodiimide (10(-5) M), inhibitors of Na+-K+-ATPase activity, block the PMA-stimulated effect but do not inhibit serum-stimulated cell division. Several stages in the cell cycle are sensitive to dbcAMP addition. One is early in the G1 phase at the time of reinitiation of the cell cycle from a stationary (Go) phase, a second is associated with the G1-S transition, and a third with passage of cells from a post-S phase to mitosis. Based on observations of early morphological changes, responses of plasma membrane enzymes and effects of enzyme inhibitors, the stimulation of cell division in BALB/c-3T3 cells by PMA or serum appears to involve several membrane functions which may act in a cooperative manner.
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Cohen R, Pacifici M, Rubinstein N, Biehl J, Holtzer H. Effect of a tumour promoter on myogenesis. Nature 1977; 266:538-40. [PMID: 859620 DOI: 10.1038/266538a0] [Citation(s) in RCA: 200] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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48
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van Duuren BL, Banerjee S, Witz G. Fluorescence studies on the interaction of the tumor promoter phorbol myristate acetate and related compounds with rat liver plasma membranes. Chem Biol Interact 1976; 15:233-46. [PMID: 187350 DOI: 10.1016/0009-2797(76)90149-6] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The interaction of the potent tumor-promoting agent phorbol myristate acetate (PMA) with purified rat liver plasma membranes suspended in phosphate-buffered saline (PBS), pH 7.4, was studied by fluorescence spectrophotometry. Exposure of membranes to PMA caused up to 21% decrease of the native membrane emission, i.e. the fluorescence of both tryptophan and tyrosine, compared to non-treated membranes. The decrease in the membrane emission varied with both the PMA and the membrane concentration. Treatment of rat liver plasma membranes with biologically less active analogs of PMA, phorbolol myristate acetate (PHMA) and 4a alpha-phorbol didecanoate (4a alpha-PDD), resulted in a 5-10% decrease of the native membrane emission. These studies suggest that PMA causes alterations in membrane structure which are due, at least in part, to conformational changes in the membrane proteins.
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Barton MA, Diener E. A new perspective on B cell triggering: control of the immune response by organizational changes in the lipid bilayer. Immunol Rev 1975; 23:5-22. [PMID: 49106 DOI: 10.1111/j.1600-065x.1975.tb00145.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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