1
|
Pinchuk AN, Rampy MA, Longino MA, Durkee BY, Counsell RE, Weichert JP. Effect of Polar Head Group Modifications on the Tumor Retention of Phospholipid Ether Analogs: Role of the Quaternary Nitrogen. Pharmaceutics 2023; 15:pharmaceutics15010171. [PMID: 36678801 PMCID: PMC9865954 DOI: 10.3390/pharmaceutics15010171] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Revised: 12/19/2022] [Accepted: 12/21/2022] [Indexed: 01/05/2023] Open
Abstract
We have previously described the remarkable capacity of radioiodinated alkyl phospholipids to be sequestered and retained by a variety of tumors in vivo. We have already established the influence of certain structural parameters of iodinated alkyl phospholipids on tumor avidity, such as stereochemistry at the sn-2 carbon of alkylglycerol phosphocholines, meta-or para-position of iodine in the aromatic ring of phenylalkyl phosphocholines, and the length of the alkyl chain in alkyl phospholipids. In order to determine the additional structural requirements for tumor uptake and retention, three new radioiodinated alkylphospholipid analogs, 2-4, were synthesized as potential tumor imaging agents. Polar head groups were modified to determine structure-tumor avidity relationships. The trimethylammonio group in 1 was substituted with a hydrogen atom in 2, an ammonio group in 3 and a tertiary butyl group in 4. All analogs were separately labeled with iodine-125 or iodine-124 and administered to Walker 256 tumor-bearing rats or human PC-3 tumor-bearing SCID mice, respectively. Tumor uptake was assessed by gamma-camera scintigraphy (for [I-125]-labeled compounds) and high-resolution micro-PET scanning (for [I-124]-labeled compounds). It was found that structural modifications in the polar head group of alkyl phospholipids strongly influenced the tumor uptake and tissue distribution of these compounds in tumor-bearing animals. Phosphoethanolamine analog 3 (NM401) displayed a very slight accumulation in tumor as compared with phosphocholine analog 1 (NM346). Analogs 2 (NM400) and 4 (NM402) lacking the positively charged nitrogen atom failed to display any tumor uptake and localized primarily in the liver. This study provided important insights regarding structural requirements for tumor uptake and retention. Replacement of the quaternary nitrogen in the alkyl phospholipid head group with non-polar substituents resulted in loss of tumor avidity.
Collapse
Affiliation(s)
- Anatoly N. Pinchuk
- Department of Radiology, University of Wisconsin School of Medicine and Public Health, 1111 Highland Ave., WIMR, Madison, WI 53705, USA
- Correspondence:
| | - Mark A. Rampy
- Department of Pharmacology, The University of Michigan Medical School, 1150 W. Medical Center Drive, Ann Arbor, MI 48109, USA
| | - Marc A. Longino
- Department of Radiology, University of Wisconsin School of Medicine and Public Health, 1111 Highland Ave., WIMR, Madison, WI 53705, USA
| | - Ben Y. Durkee
- Department of Radiology, University of Wisconsin School of Medicine and Public Health, 1111 Highland Ave., WIMR, Madison, WI 53705, USA
| | - Raymond E. Counsell
- Department of Pharmacology, The University of Michigan Medical School, 1150 W. Medical Center Drive, Ann Arbor, MI 48109, USA
| | - Jamey P. Weichert
- Department of Radiology, University of Wisconsin School of Medicine and Public Health, 1111 Highland Ave., WIMR, Madison, WI 53705, USA
| |
Collapse
|
2
|
Schwartze W, Roos W. The signal molecule lysophosphatidylcholine in Eschscholzia californica is rapidly metabolized by reacylation. PLANTA 2008; 229:183-91. [PMID: 18807068 DOI: 10.1007/s00425-008-0819-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2008] [Accepted: 09/04/2008] [Indexed: 05/08/2023]
Abstract
In cultured cells of California poppy (Eschscholzia californica), lysophosphatidylcholine (LPC) triggers a signal path that finally induces alkaloid biosynthesis. LPC is transiently generated by elicitor-activated phospholipase A(2) of the plasma membrane. Externally added LPC is rapidly acylated by a membrane-bound enzyme that shows the highest specific activity in the purified plasma membrane. The fatty acid incorporated into the sn-2 position of LPC is preferentially linoleic (18:2), which is the most abundant acyl component in the PC species of Eschscholzia cells, but a minor component of the pool of free fatty acids. The fatty acid at the sn-1 position of LPC is less important for substrate specificity. The capacity of LPC acylation by intact cells or isolated plasma membranes by far exceeds the rate of LPC generation by activated phospholipase A(2) and is not limited by the availability of acyl donors. Metabolites other than phosphatidylcholine (PC) were not significantly produced from labeled LPC within 20 min, indicating that lysophospholipases are not significantly contributing to the short-time metabolism of LPC. It is concluded that reacylation to PC is the dominating process in the detoxication of LPC and ensures the transient character of its steady state concentrations, even at maximum phospholipase A(2) activities.
Collapse
Affiliation(s)
- Wieland Schwartze
- Fakultät Biowissenschaften, Institut für Pharmazie, Bereich Pharmazeutische Biologie und Pharmakologie, Abteilung Molekulare Zellbiologie, Martin-Luther-Universität Halle-Wittenberg, Kurt-Mothes-Str. 3, 06120 Halle, Germany
| | | |
Collapse
|
3
|
Mollinedo F. Antitumour ether lipids: proapoptotic agents with multiple therapeutic indications. Expert Opin Ther Pat 2007. [DOI: 10.1517/13543776.17.4.385] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
|
4
|
Conesa-Zamora P, Mollinedo F, Corbalán-García S, Gómez-Fernández JC. A comparative study of the effect of the antineoplastic ether lipid 1-O-octadecyl-2-O-methyl-glycero-3-phosphocholine and some homologous compounds on PKCα and PKCɛ. Biochim Biophys Acta Mol Cell Biol Lipids 2005; 1687:110-9. [PMID: 15708359 DOI: 10.1016/j.bbalip.2004.11.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2004] [Revised: 11/11/2004] [Accepted: 11/11/2004] [Indexed: 11/25/2022]
Abstract
The effects of the anti-neoplastic ether lipid ET-18-OCH3 and some structural homologues on the activity of protein kinase C alpha (PKC alpha) were studied and compared with the effects the same had on the activity of PKC epsilon. ET-18-OCH3 progressively inhibited the activity of PKC alpha as the concentration was increased up to 30 mol% of the total lipid, above which the effect was one of activation. The experiments carried out with the homologues showed that the methoxy group bound at the sn-2 position of the glycerol of ET-18-OCH3 is essential for both the initial inhibitory effect and the subsequent activation effect. On the other hand, variations in the type of bond linking substitutions in the sn-1 position, ether or ester, do not seem to play an important role in determining the activity of the enzyme. The effects were different on PKC epsilon since ET-18-OCH3 had a triphasic effect, activating the enzyme at low concentrations, inhibiting it at slightly higher concentrations and then activating it again at higher concentrations. In this case, when the homologues were used, it was observed that the presence of the methoxy group linked to the sn-2 position of glycerol and the type of bond linking substitutions to the sn-1 position were important for activating the enzyme, so that only homologues with ester bonds as LPC and PAPC were able to induce the initial activation step in a way similar to ET-18-OCH3. Substitution of the phosphocholine group of ET-18-OCH3 by phosphoserine led to a greater activation of PKC alpha, an effect that comes from the Ca(2+)-phospholipid binding site probably because of the specific interaction of this site with the phosphoserine group. The action of ET-18-OCH3 and its homologues, as demonstrated in this paper, may permit the selective inhibition or activation of PKC alpha and PKC epsilon by using the most suitable range of concentrations.
Collapse
Affiliation(s)
- Pablo Conesa-Zamora
- Departamento de Bioquímica y Biología Molecular A, Facultad de Veterinaria, Universidad de Murcia, Apartado de Correos 4021, E-30080-Murcia, Spain
| | | | | | | |
Collapse
|
5
|
Wright MM, Howe AG, Zaremberg V. Cell membranes and apoptosis: role of cardiolipin, phosphatidylcholine, and anticancer lipid analogues. Biochem Cell Biol 2004; 82:18-26. [PMID: 15052325 DOI: 10.1139/o03-092] [Citation(s) in RCA: 119] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The apoptotic program utilizes cellular membranes to transduce and generate operative signals. Lipids are major components of cellular membranes and have the potential to control the effectiveness of the signal by directing it to the proper location, being a source of new signals or as mediators in the response. These possible lipid functions are illustrated in the present review, focussing on the role that two different phospholipids, cardiolipin and phosphatidyl choline, play in apoptosis. Mitochondria have a central role in apoptosis, and many important aspects of the process mediated by this organelle converge through its distinctive lipid cardiolipin. Specifically, changes in cardiolipin metabolism have been detected in early steps of the death program and it is postulated (i) to mediate recruitment of pro apoptotic proteins like Bid to the mitochondria surface and (ii) to actively participate in the release of proteins relevant for the execution phase of apoptosis, like cytochrome c. Unlike the organelle specific distribution of cardiolipin, phosphatidylcholine is widely distributed among all organelles of the cell. The importance of phosphatidylcholine in apoptosis has been approached mainly through the study of the mode of action of (i) phosphatidylcholine anticancer analogues such as edelfosine and (ii) molecules that alter phosphatidylcholine metabolism, such as farnesol. The contribution of phosphatidylcholine metabolism to the apoptotic program is discussed, analyzing the experimental evidence available and pointing out some controversies in the proposed mechanisms of action.
Collapse
Affiliation(s)
- Marcia M Wright
- Department of Pediatrics, Atlantic Research Centre, Dalhousie University, Halifax, NS, Canada
| | | | | |
Collapse
|
6
|
Aroca JD, Sánchez-Piñera P, Corbalán-García S, Conesa-Zamora P, de Godos A, Gómez-Fernández JC. Correlation between the effect of the anti-neoplastic ether lipid 1-O-octadecyl-2-O-methyl-glycero-3-phosphocholine on the membrane and the activity of protein kinase Calpha. EUROPEAN JOURNAL OF BIOCHEMISTRY 2001; 268:6369-78. [PMID: 11737191 DOI: 10.1046/j.0014-2956.2001.02554.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The antineoplastic ether phospholipid 1-O-octadecyl-2-O-methyl-sn-glycero-3-phophocholine (ET-18-OCH3) was incorporated into dimyristoylglycerophosphocholine (Myr2Gro-PCho)/dimyristoylglycerophosphoserine (Myr2Gro-PSer) (4 : 1 molar ratio) mixtures. Electron microscopy showed that the addition of ET-18-OCH3 reduced the size of the vesicles. Small vesicles could be detected even at 60 mol% ET-18-OCH3. Sedimentation studies showed the increasing presence of phospholipids in the supernatant, while turbidity measurements indicated a decrease in absorbance as the ET-18-OCH3 concentration was increased. These findings may be explained by the formation of small vesicles and/or mixed micelles. Infrared spectroscopy showed that at 60 mol% the fluidity of the membrane was considerably increased at temperatures below the phase transition, with only a small increase in the proportion of gauche isomers after the gel-to-fluid phase transition of this sample. On the other hand, protein kinase Calpha (PKCalpha) activity progressively decreased when ET-18-OCH3 was incorporated into multilamellar vesicles, reaching a minimum value at 20 mol%, this inhibition being attributed to the modification of the membrane produced by a cone-shaped molecule. At higher concentrations, however, ET-18-OCH3 activated the enzyme with a maximum being attained at 50 mol%. This activation being attributed to the formation of small vesicles and/or micelles. At still higher concentrations of ET-18-OCH3 the enzyme was once again inhibited, inhibition being almost complete at 80 mol%. When PKC was assayed using large unilamellar vesicles a slight activation was observed at very low ET-18-OCH3 concentrations.
Collapse
Affiliation(s)
- J D Aroca
- Departamento de Bioquímica y Biología Molecular 'A', Facultad de Veterinaria, Universidad de Murcia, Apartado de Correos, Murcia, Spain
| | | | | | | | | | | |
Collapse
|
7
|
Lykidis A, Jackowski S. Regulation of mammalian cell membrane biosynthesis. PROGRESS IN NUCLEIC ACID RESEARCH AND MOLECULAR BIOLOGY 2000; 65:361-93. [PMID: 11008493 DOI: 10.1016/s0079-6603(00)65010-9] [Citation(s) in RCA: 89] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
This review explores current information on the interrelationship between phospholipid biochemistry and cell biology. Phosphatidylcholine is the most abundant phospholipid and it biosynthesis has been studied extensively. The choline cytidylyltransferase regulates phosphatidylcholine production, and recent advances in our understanding of the mechanisms that govern cytidylyltransferase include the discovery of multiple isoforms and a more complete understanding of the lipid regulation of enzyme activity. Similarities between phosphatidylcholine formation and the phosphatidylethanolamine and phosphatidylinositol biosynthetic pathways are discussed, together with current insight into control mechanisms. Membrane phospholipid doubling during cell cycle progression is a function of periodic biosynthesis and degradation. Membrane homeostasis is maintained by a phospholipase A-mediated degradation of excess phospholipid, whereas insufficient phosphatidylcholine triggers apoptosis in cells.
Collapse
Affiliation(s)
- A Lykidis
- Department of Biochemistry, St. Jude Children's Research Hospital, Memphis, Tennessee 38105, USA
| | | |
Collapse
|
8
|
Spiegel S, Olah Z, Cuvillier O, Edsall LC, Janoff AS. Differential effects of free and liposome-associated 1-O-octadecyl-2-O-methylglycerophosphocholine on protein kinase C. FEBS Lett 1999; 454:137-41. [PMID: 10413111 DOI: 10.1016/s0014-5793(99)00796-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Incorporation of ET-18-OCH3 into well-characterized liposomes known as ELL-12 has eliminated its gastrointestinal and hemolytic toxicity without loss of growth inhibiting activity. ET-18-OCH3, but not ELL-12, blunted the increase in membrane protein kinase C (PKC) activity induced by 12-O-tetradecanoylphorbol 13-myristate (TPA) and markedly reduced levels of PKC alpha in NIH 3T3 fibroblasts. Furthermore, prolonged treatment with ELL-12 neither inhibited TPA-induced translocations of PKC alpha and PKC delta to the particulate fraction nor caused down-regulation, and did not affect the cellular distribution of TPA-insensitive PKC zeta. In Jurkat T cells, where ELL-12 markedly induced apoptosis that was blocked by an inhibitor of caspase-3-like activities, it had no effect on PKC activity or translocation induced by TPA. Thus, it seems unlikely that PKC is involved in the therapeutic effects of ELL-12.
Collapse
Affiliation(s)
- S Spiegel
- Department of Biochemistry and Molecular Biology, Georgetown University Medical Center, Washington, DC 20007, USA.
| | | | | | | | | |
Collapse
|
9
|
Koller-Lucae SK, Schott H, Schwendener RA. Low density lipoprotein and liposome mediated uptake and cytotoxic effect of N4-octadecyl-1-beta-D-arabinofuranosylcytosine in Daudi lymphoma cells. Br J Cancer 1999; 80:1542-9. [PMID: 10408395 PMCID: PMC2363091 DOI: 10.1038/sj.bjc.6690558] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Low density lipoprotein (LDL) receptor-mediated uptake and cytotoxic effects of N4-octadecyl-1-beta-D-arabinofuranosylcytosine (NOAC) were studied in Daudi lymphoma cells. NOAC was either incorporated into LDL or liposomes to compare specific and unspecific uptake mechanisms. Binding of LDL to Daudi cells was not altered after NOAC incorporation (K(D) 60 nM). Binding of liposomal NOAC was not saturable with increasing concentrations. Specific binding of NOAC-LDL to Daudi cells was five times higher than to human lymphocytes. LDL receptor binding could be blocked and up- or down-regulated. Co-incubation with colchicine reduced NOAC-LDL uptake by 36%. These results suggested that NOAC-LDL is taken up via the LDL receptor pathway. In an in vitro cytotoxicity test, the IC50 of NOAC-LDL was about 160 microM, whereas with liposomal NOAC the IC50 was 40 microM. Blocking the LDL receptors with empty LDL protected 50% of the cells from NOAC cytotoxicity. The cellular distribution of NOAC-LDL or NOAC-liposomes differed only in the membrane and nuclei fraction with 13% and 6% respectively. Although it is more convenient to prepare NOAC-liposomes as compared to the loading of LDL particles with the drug, the receptor-mediated uptake of NOAC-LDL provides an interesting rationale for the specific delivery of the drug to tumours that express elevated numbers of LDL receptors.
Collapse
Affiliation(s)
- S K Koller-Lucae
- Department of Pathology, University Hospital, Zurich, Switzerland
| | | | | |
Collapse
|
10
|
Botzler C, Ellwart J, Günther W, Eissner G, Multhoff G. Synergistic effects of heat and ET-18-OCH3 on membrane expression of hsp70 and lysis of leukemic K562 cells. Exp Hematol 1999; 27:470-8. [PMID: 10089909 DOI: 10.1016/s0301-472x(98)00055-1] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
We previously reported that cell surface expression of hsp70, the major stress inducible member of the 70-kDa heat shock protein family, is inducible by nonlethal heat as well as by treatment with the membrane-interactive compound alkyl-lysophospholipid 1-octadecyl-2-methyl-rac-glycero-3-phosphocholine (ET-18-OCH3) selectively on human tumor cell lines. Plasma membrane expression of hsp70 increases selectively the sensitivity of tumor cells to lysis and, therefore, might play an important role in the antitumor immune response. Here, we demonstrate that a combined treatment consisting of sublethal heat (41.8 degrees C) and a noncytotoxic concentration of ET-18-OCH3 (25 micrograms/mL) results in a synergistic increase in the amount of cell membrane-bound hsp70 on leukemic K562 cells and on freshly isolated bone marrow of a chronic myelogeneous leukemia (CML) patient, but not on peripheral blood lymphocytes or CD34+ hematopoietic progenitor cells of healthy human individuals. Under these conditions the repopulating capacity of progenitor cells was not influenced. The increased hsp70 membrane expression on leukemic K562 cells results in a significantly increased sensitivity to lysis mediated by natural killer cells. In contrast to leukemic cells, the lysis of peripheral blood lymphocytes and CD34+ progenitor cells that lack expression of hsp70 on their plasma membrane was not negatively influenced by this treatment. A nonspecific disruption of the plasma membrane could be excluded, because treatment with a nontoxic concentration of the detergent Tween20 did not have an influence on hsp70 cell surface expression or on the sensitivity to lysis. Our findings might have further clinical implications with respect to purging of bone marrow from patients suffering from leukemia at sublethal conditions to induce a tumor-selective immune response.
Collapse
Affiliation(s)
- C Botzler
- GSF-Institute of Molecular Immunology, Munich, Germany
| | | | | | | | | |
Collapse
|
11
|
Boucrot P, Bobin-Dubigeon C, Elkihel L, Letourneux Y, Jugé M, Gandemer G, Petit JY. Secreted and intracellular phospholipases A2 inhibition by 1-decyl 2-octyl-glycerophosphocholine in rat peritoneal macrophages. Fundam Clin Pharmacol 1998; 12:433-41. [PMID: 9711466 DOI: 10.1111/j.1472-8206.1998.tb00968.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Compounds able to inhibit phospholipases A2 can be considered as potential anti-inflammatory drugs. In this respect, the inhibitory effect of the phospholipid analogue 1-decyl 2-octyl-rac-glycero-3-phosphocholine (decyloctyl-GPC) added to the culture medium of rat peritoneal macrophages stimulated with ionophore A23187 was determined. (a) The substrate of phospholipase A2 1-octadecanoyl 2-[14C]eicosatetraenoyl-sn-glycero-3-phosphocholine ([14C]20:4-GPC) was added to the culture medium. In macrophages + extracellular fluids, its hydrolysis at the 2-position, produced [14C]non-phosphorous lipids which reached 12% of the dose at 0.14 microM, 73% at 0.9 and > 90% at 1.6 microM; in experiments where macrophages and extracellular fluids were analyzed separately, decyloctyl-GPC initially added at 4 microM, significantly inhibited the release of [14C]fatty acids and the eicosanoid synthesis, demonstrating its ability to inhibit secreted and/or intracellular phospholipases A2. (b) Extracellular fluids were separated from the macrophages and incubated with [14C]20:4-GPC: 48% of the dose was hydrolyzed by extracellular fluid-associated secreted phospholipase A2 and decyloctyl-GPC at 3 microM, reduced this hydrolysis by 50%. (c) [3H]arachidonic acid ([3H]20:4) was added to the culture medium and was esterified in the macrophage membrane phospholipids. Activation of intracellular phospholipase A2 induced the release of [3H] fatty acids and eicosanoid synthesis. These releases were inhibited by 50% with decyloctyl-GPC added at 4 microM. (d) [3H]20:4 and [14C]20:4-GPC were added to the culture medium of the macrophages. [3H] and [14C] fatty acids and eicosanoids were released in macrophages or extracellular fluids. They were significantly reduced by the phospholipid analogue added at 4 microM. It is concluded that secreted and intracellular phospholipases A2 were both inhibited by decyloctyl-GPC which extensively reduced the 20:4 release from exogenous and membrane phospholipids and therefore eicosanoid synthesis.
Collapse
Affiliation(s)
- P Boucrot
- Laboratoire d'étude des interactions des molécules alimentaires, INRA, Nantes, France
| | | | | | | | | | | | | |
Collapse
|
12
|
Baburina I, Jackowski S. Apoptosis triggered by 1-O-octadecyl-2-O-methyl-rac-glycero-3-phosphocholine is prevented by increased expression of CTP:phosphocholine cytidylyltransferase. J Biol Chem 1998; 273:2169-73. [PMID: 9442058 DOI: 10.1074/jbc.273.4.2169] [Citation(s) in RCA: 88] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
A HeLa cell line was constructed for the regulation of CTP:phosphocholine cytidylyltransferase (CCT) expression via a tetracycline-responsive promoter to test the role of CCT in apoptosis triggered by exposure of cells to the antineoplastic phospholipid 1-O-octadecyl-2-O-methyl-rac-glycero-3-phosphocholine (ET-18-OCH3). Basal CCT expression in the engineered HeLa cell line was the same as in control HeLa cells lines, and CCT activity and protein were elevated 25-fold following 48 h of induction with doxycycline. Increased CCT expression prevented ET-18-OCH3-induced apoptosis. Acylation of exogenous lysophosphatidylcholine circumvented the requirement for CCT activity by providing an alternate route to phosphatidylcholine, and heightened CCT expression and lysophosphatidylcholine supplementation were equally effective in reversing the cytotoxic effect of ET-18-OCH3. Neither CCT overexpression nor lysophosphatidylcholine supplementation allowed the HeLa cells to proliferate in the presence of ET-18-OCH3, indicating that the cytostatic property of ET-18-OCH3 was independent of its effect on membrane phospholipid synthesis. These data provide compelling genetic evidence to support the conclusion that the interruption of phosphatidylcholine synthesis at the CCT step by ET-18-OCH3 is the primary physiological imbalance that accounts for the cytotoxic action of the drug.
Collapse
Affiliation(s)
- I Baburina
- Department of Biochemistry, St. Jude Children's Research Hospital, Memphis, Tennessee 38105, USA
| | | |
Collapse
|
13
|
Boggs K, Rock CO, Jackowski S. The antiproliferative effect of hexadecylphosphocholine toward HL60 cells is prevented by exogenous lysophosphatidylcholine. BIOCHIMICA ET BIOPHYSICA ACTA 1998; 1389:1-12. [PMID: 9443598 DOI: 10.1016/s0005-2760(97)00145-8] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The mechanisms that account for the anti-proliferative properties of the biologically active lysophospholipid analog hexadecylphosphocholine (HexPC) were investigated in HL60 cells. HexPC inhibited the incorporation of choline into phosphatidylcholine and the pattern of accumulation of soluble choline-derived metabolites pinpointed CTP:phosphocholine cytidylyltransferase (CT) as the inhibited step in vivo. HexPC also inhibited recombinant CT in vitro. HexPC treatment led to accumulation of cells in G2/M phase, triggered DNA fragmentation and caused morphological changes associated with apoptosis. The supplementation of HexPC-treated cells with exogenous lysophosphatidylcholine (LPC) completely reversed the cytotoxic effects of HexPC and restored HL60 cell proliferation in the presence of the drug. LPC provided an alternate pathway for phosphatidylcholine synthesis via the acylation of exogenous LPC. This result contrasted with the response of HL60 cells to 1-O-octadecyl-2-O-methyl-rac-glycero-3-phosphocholine (ET-18-OCH3) where LPC overcame the cytotoxic effects but did not support continued cell proliferation. Morphological integrity, DNA stability and cell viability were maintained in cells treated with LPC plus either antineoplastic agent. Thus the inhibition of phosphatidylcholine biosynthesis at the CT step accounts for the cytotoxicity of both HexPC and ET-18-OCH3 which is overridden by providing an alternate pathway for phosphatidylcholine synthesis via the acylation of exogenous LPC.
Collapse
Affiliation(s)
- K Boggs
- Department of Biochemistry, St. Jude Children's Research Hospital, Memphis, TN 38101-3018, USA
| | | | | |
Collapse
|
14
|
Mayhew E, Ahmad I, Bhatia S, Dause R, Filep J, Janoff AS, Kaisheva E, Perkins WR, Zha Y, Franklin JC. Stability of association of 1-O-octadecyl-2-O-methyl-sn-glycero-3-phosphocholine with liposomes is composition dependent. BIOCHIMICA ET BIOPHYSICA ACTA 1997; 1329:139-48. [PMID: 9370251 DOI: 10.1016/s0005-2736(97)00102-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The ether lipid, 1-O-octadecyl-2-O-methyl-sn-glycero-3-phosphocholine (ET-18-OCH3), has anticancer activity, but it has serious side-effects, including hemolysis, which prevent its optimal use. We surmised if ET-18-OCH3 could be stably associated with liposomes, less free ET-18-OCH3 would be available for lytic interaction with red cells. Liposome composition variables investigated included acyl chain saturation, phospholipid head group and mole ratio of Chol and ET-18-OCH3. It was found that attenuation of hemolysis was strongly liposome composition dependent. Some ET-18-OCH3 liposome compositions were minimally hemolytic. For example, whereas the HI5 (drug concentration required to cause 5% human red cell lysis) was 5-6 microM for free ET-18-OCH3, it was approximately 250 microM for DOPC (dioleoylphosphatidylcholine):Chol (cholesterol):DOPE-GA (glutaric acid derivatized DOPE):ET-18-OCH3, (4:3:1:2) and 640 microM for DOPE (dioleyolphosphatidylethanolamine):Chol:DOPE-GA:ET-18-OCH3 (4:3:1:2) liposomes. Efflux of carboxyfluorescein (CF) from liposomes and Langmuir trough determinations of mean molecular area of lipids in monolayers (MMAM) were used as indicators of membrane packing and stability. Incorporation of ET-18-OCH3 in liposomes reduced the MMAM. Reduction in CF permeation was correlated with reduction in hemolysis. The most stable liposomes included components, such as cholesterol, DOPC and DOPE, which have complementary shapes to ET-18-OCH3.
Collapse
Affiliation(s)
- E Mayhew
- The Liposome Company Inc., Princeton Forrestal Center, NJ 08540-6619, USA
| | | | | | | | | | | | | | | | | | | |
Collapse
|
15
|
Boggs KP, Rock CO, Jackowski S. Lysophosphatidylcholine attenuates the cytotoxic effects of the antineoplastic phospholipid 1-O-octadecyl-2-O-methyl-rac-glycero-3- phosphocholine. J Biol Chem 1995; 270:11612-8. [PMID: 7744800 DOI: 10.1074/jbc.270.19.11612] [Citation(s) in RCA: 73] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
A colony-stimulating factor 1-dependent cell line was used to determine the relationship between the inhibition of phospholipid synthesis and the cytotoxic activity of the antineoplastic ether lipid, 1-O-octadecyl-2-O-methyl-rac-glycero-3-phosphocholine (ET-18-OCH3). ET-18-OCH3 inhibited choline incorporation into phosphatidylcholine as well as total phospholipid synthesis. Exposure to ET-18-OCH3 at the G1/S boundary led to the accumulation of cells in G2, whereas the addition of ET-18-OCH3 in the G1 phase of the cell cycle prevented entry into the S phase. In both cases, ET-18-OCH3 treatment triggered DNA fragmentation and morphological changes associated with apoptosis within 10 h. The addition of lysophosphatidylcholine provided an exogenous source of cellular phospholipid and prevented ET-18-OCH3-dependent accumulation of cells in G2 and apoptosis. However, lysophosphatidylcholine did not overcome the ET-18-OCH3-dependent G1 block, although the growth-arrested cells remained viable. These data indicate that restoring phosphatidylcholine synthesis by supplementation with lysophosphatidylcholine overrides the cytotoxic but not the cytostatic activity of ET-18-OCH3.
Collapse
Affiliation(s)
- K P Boggs
- Department of Biochemistry, St. Jude Children's Research Hospital, Memphis, Tennessee 38101, USA
| | | | | |
Collapse
|
16
|
Affiliation(s)
- W J Houlihan
- Charles A. Dana Research Institute for Scientists Emeriti, Drew University, Madison, New Jersey 07940-4000, USA
| | | | | | | |
Collapse
|
17
|
Brachwitz H, Vollgraf C. Analogs of alkyllysophospholipids: chemistry, effects on the molecular level and their consequences for normal and malignant cells. Pharmacol Ther 1995; 66:39-82. [PMID: 7630930 DOI: 10.1016/0163-7258(95)00001-w] [Citation(s) in RCA: 81] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
In the search for new approaches to cancer therapy, the first alkyllysophospholipid (ALP) analogs were designed and studied about two decades ago, either as potential immunomodulators or as antimetabolites of phospholipid metabolism. In the meantime, it has been demonstrated that they really act in this way. However, their special importance is based on the fact that, in addition, they interfere with key events of signal transduction, such as hormone (or cytokine)-receptor binding or processing, protein kinase C or phospholipase C function and phosphatidylinositol and calcium metabolism. There are no strict structural requirements for their activity. Differences in the cellular uptake or the state of cellular differentiation seem to be mainly responsible for higher or lower sensitivities of cells towards ALP analogs. Consequences of the molecular effects mentioned on the cellular level are cytostasis, induction of differentiation (while in contrast the effects of known inducers of differentiation such as 12-O-tetradecanoylphorbol-13-acetate are inhibited, probably as a consequence of protein kinase C inhibition) and loss of invasive properties. Already in sublytic concentrations, alterations in the membrane structure were observed, and lysis may begin at concentrations not much higher than those causing the other effects described. Few ALP analogs have already entered clinical studies or are in clinical use. ALP analogs are the only antineoplastic agents that do not act directly on the formation and function of the cellular replication machinery. Therefore, their effects are independent of the proliferative state of the target cells. Because of their interference with cellular regulatory events, including those failing in cancer cells, ALP analogs, beyond their clinical importance, are interesting model compounds for the development of new, more selective drugs for cancer therapy.
Collapse
Affiliation(s)
- H Brachwitz
- Department of Hematology and Oncology, Klinikum Steglitz, Freie Universität Berlin, Germany
| | | |
Collapse
|
18
|
Boggs KP, Rock CO, Jackowski S. Lysophosphatidylcholine and 1-O-octadecyl-2-O-methyl-rac-glycero-3-phosphocholine inhibit the CDP-choline pathway of phosphatidylcholine synthesis at the CTP:phosphocholine cytidylyltransferase step. J Biol Chem 1995; 270:7757-64. [PMID: 7706325 DOI: 10.1074/jbc.270.13.7757] [Citation(s) in RCA: 123] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The regulation of the CDP-choline pathway of phosphatidylcholine synthesis at the CTP:phosphocholine cytidylyltransferase (CT) step by lysophosphatidylcholine (LPC) and the nonhydrolyzable LPC analog, 1-O-octadecyl-2-O-methyl-rac-glycero-3-phosphocholine (ET-18-OCH3), was investigated in a colony-stimulating factor 1-dependent murine macrophage cell line. LPC inhibited phosphatidylcholine synthesis in vivo and led to the accumulation of choline and phosphocholine coupled to the disappearance of CDP-choline pointing to CT as the intracellular target. LPC neither inhibited cell growth nor decreased the cellular content of CT or altered the distribution of CT between soluble and particulate subcellular fractions. The inhibition of phosphatidylcholine synthesis was specific for LPC since lysophospholipids lacking the choline headgroup were not inhibitors. ET-18-OCH3 was a more potent inhibitor of phosphatidylcholine synthesis than LPC and caused the translocation of CT from the soluble compartment to the particulate compartment. Both LPC and ET-18-OCH3 were inhibitors of CT activity in vitro and kinetic analysis showed competitive inhibition with respect to the lipid activator. These data point to LPC as a negative regulator of de novo phosphatidylcholine synthesis that acts at the CT step and establish the mechanism for the inhibition of phosphatidylcholine biosynthesis by antineoplastic phospholipids.
Collapse
Affiliation(s)
- K P Boggs
- Department of Biochemistry, St. Jude Children's Research Hospital, Memphis, Tennessee 38101, USA
| | | | | |
Collapse
|
19
|
Synthesis of 1-O-alkyl-2-methoxy-sn-glycero-3-phosphocholine from alkylglyceryl ethers of Commander Island squid liver and its biological activity. Pharm Chem J 1995. [DOI: 10.1007/bf02226517] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
|
20
|
Adany I, Yazlovitskaya EM, Haug JS, Voziyan PA, Melnykovych G. Differences in sensitivity to farnesol toxicity between neoplastically- and non-neoplastically-derived cells in culture. Cancer Lett 1994; 79:175-9. [PMID: 8019976 DOI: 10.1016/0304-3835(94)90257-7] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Six neoplastically-derived cell lines and three cell lines derived from normal tissues were compared for their sensitivity to isoprenoid trans-trans farnesol. Assays of cell numbers and of protein concentrations per culture revealed greater sensitivity of neoplastic cells than of the normal cells. Similar differences were obtained from the comparison of incorporation of [methyl-3H]choline into cellular lipids, with neoplastic cells showing greater inhibition than normal cells.
Collapse
Affiliation(s)
- I Adany
- Department of Microbiology, Molecular Genetics and Immunology, University of Kansas Medical Center, Kansas City 66103
| | | | | | | | | |
Collapse
|
21
|
|
22
|
Affiliation(s)
- F Paltauf
- Institut für Biochemie und Lebensmittelchemie der Technischen Universität Graz, Austria
| | | |
Collapse
|
23
|
Abstract
Many investigators have embarked upon the search for novel cellular targets for the treatment of cancer. A popular therapeutic strategy is to intervene with the components of cellular signalling systems that are altered during malignancy. The molecular heterogeneity of the protein kinase C (PKC) family and their functional divergence make them attractive targets for anticancer drug development. PKC can also influence the sensitivity of tumor tissue to conventional cytotoxic drugs. As discussed in this review, a complete understanding of the PKC signal transduction pathway is obligatory for the selective destruction of tumor tissue by exploiting PKC as either a target or a modulator of cancer chemotherapeutic agents.
Collapse
Affiliation(s)
- A Basu
- Department of Pharmacology, University of Pittsburgh School of Medicine, PA 15261
| |
Collapse
|
24
|
Vogler WR, Berdel WE. Autologous bone marrow transplantation with alkyl-lysophospholipid-purged marrow. JOURNAL OF HEMATOTHERAPY 1993; 2:93-102. [PMID: 7921970 DOI: 10.1089/scd.1.1993.2.93] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Autologous bone marrow transplantation (ABMT) appears to offer clinical benefit to leukemia patients, but the major reason for failure is relapse. This may be related to the presence of residual leukemic cells in the harvested marrow. To circumvent this problem, various procedures have been developed to purge ex vivo residual leukemic cells from the marrow. The alkyl-lysophospholipids are a new group of anticancer drugs that target membranes as their major site of action. They are unique in that they are relatively selectively toxic to neoplastic cells and spare normal marrow stem cells and progenitor cells. The most active compound is edelfosine. Twenty-nine patients with acute leukemia in second or subsequent remission or early relapse or in first remission, either with a history of treated extramedullary relapse, or requiring more than one induction program to achieve remission, underwent ablative therapy followed by infusion of autologous marrow which had been purged by a 4-hour exposure to edelfosine prior to cryopreservation. Thirty-one percent of the patients are alive and free of leukemia for a median of 630 days (range 185-1,613). These results in this high-risk group of patients warrant further investigation.
Collapse
Affiliation(s)
- W R Vogler
- Department of Medicine, Emory University, Atlanta, GA 30322
| | | |
Collapse
|
25
|
Herrmann DB, Opitz HG, Munder PG. Antitumor activity of Ilmofosine (BM 41.440) in the 3Lewis-lung carcinoma model. Lipids 1991; 26:1431-6. [PMID: 1819746 DOI: 10.1007/bf02536581] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Ilmofosine (1-hexadecylthio-2-methoxymethyl-1,3-propanediol-phosphocholine, BM 41.440) is a thioether phospholipid with cytostatic/cytotoxic properties. The antineoplastic activity of this compound was investigated in vivo in the 3Lewis-lung carcinoma system. 3Lewis lung tumor-bearing C57Bl/6 mice were treated with 0.625 to 40 mg Ilmofosine/kg per day p.o. either from days 1 to 9 or from days 11 to 28 after intrafoot-pad tumor cell inoculation. Ilmofosine caused a significant dose-related response on tumor growth and metastases, expressed in terms of tumor diameter, tumor weight, survival time and number of metastases-free animals as compared to sham-treated and positive (cyclophosphamide) controls. The results suggest that direct cytostatic/cytotoxic effects, rather than immune-modulatory mechanisms, preferentially contribute to the antitumor activity of Ilmofosine in vivo.
Collapse
Affiliation(s)
- D B Herrmann
- Boehringer Mannheim GmbH, Department of Immunopharmacology, Germany
| | | | | |
Collapse
|