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V Liebl

Publications and source records attributed to V Liebl.

6 recordsLinked to original sources
PubMed1993

New tumoricidal semisynthetic ether phospholipid, plasmanyl-(N-acyl)ethanolamine (PNAE(s)) and enhancement of its tumoricidal activity by calcium ions.

Recently we described a novel, nontoxic, natural ether phospholipid with selective antitumor activity, 1-0-alkyl-2-acyl-sn-glycero-3-phospho-(N-acyl)ethanolamine, i.e., plasmanyl-(N-acyl)ethanolamine (PNAE), isolated from ischemic tissue of chick embryo. The chemical structure of PNAE has been confirmed by partial synthesis. The semisynthetic preparation PNAE(s), 1-0-octadecyl-2-oleoyl-sn-glycero-3-phospho-(N-palmitoyl)ethanolamine, exhibited tumoricidal activity against human tumor cells T24 and mouse sarcoma cells Mcll as well as in vivo against murine sarcomas S-180 and Mcll. PNAE(s) selectively destroyed tumor cell membranes as has been demonstrated by scanning electron microscopy. The antitumor activity of PNAE(s) in vitro and in vivo was significantly enhanced by Ca2+ ions. These results may be explained by selective damage of tumor cell membranes by PNAE(s), increasing also the tumor cell membrane permeability for exogenous Ca2+ ions and altering the intracellular calcium homeostasis in tumor cells. By increased concentration of Ca2+ in tumor cell cytosol selective damage and lysis of tumor cells was induced. The combined use of parenteral administration of PNAE(s) and peroral doses of calcium gluconate may provide a new approach to enhancement of antitumor activity of PNAE(s) by Ca2+ in a very selective and nontoxic antitumor therapy.

Animals↗
PubMed1986

A novel nontoxic alkyl-phospholipid with selective antitumor activity, plasmanyl-(N-acyl)-ethanolamine (PNAE), isolated from degenerating chick embryonal tissues and from an anticancer biopreparation cACPL.

A novel alkyl-phospholipid with selective antitumor activity was isolated from an anticancer biopreparation cACPL (crude anticancer phospholipids) and from tissues of degenerating chick embryos. The alkyl-phospholipid was isolated and purified by chromatographic methods using silicic acid column chromatography and thin layer chromatography. The chemical structure of the alkyl-phospholipid was characterized by thin-layer chromatographic analysis of the degradation products after enzymatic digestion with phospholipase C from Bacillus cereus and with phospholipase D, by two-dimensional thin-layer chromatography, infrared spectrum, and mass spectrometric analysis. The alkyl-phospholipid was identified as 1-O-alkyl-2-acyl-sn-glycero-3-phospho-(N-acyl)-ethanolamine, i.e. plasmanyl-(N-acyl)-ethanolamine (PNAE), the main molecular species being 1-O-octadecyl-2-oleoyl-sn-glycero-3-phospho-(N-palmitoyl)-ethanol-amine. PNAE exhibits a selective cytolytic effect on human tumor cells HEp-2, HeLa and T24 in tissue cultures at the concentration of 25 micrograms PNAE per ml and 66-98% inhibition of DNA synthesis in the human tumor cells at concentration as low as 2.5 micrograms/ml, but it does not inhibit at a 50-fold higher concentration the DNA synthesis and normal growth of human fibroblasts (cell line LEP). PNAE represents the main biologically active antitumor component of the cACPL biopreparation and exhibits a significant antitumor effect in vivo in B10/An mice bearing Mc11 fibrosarcoma. Possible molecular mechanism of the selective antitumor activity of PNAE is discussed, involving the selective disturbance of phospholipid metabolism in tumor cells, leading to progressive destruction of tumor cell membranes. The fact that PNAE is nontoxic and selectively active against tumor cells at nanomolar concentrations in vitro as well as in vivo, indicates the possibility of its clinical use. PNAE and cACPL biopreparation might provide a very useful new tool for human anticancer chemotherapy.

Animals↗
PubMed1984

The evolution of prebiological self-organization: probable colloid-chemical evolution of first prokaryotic cells.

This is an attempt to analyse the mechanisms of self-assembly in the course of the origin and early evolution of life on the Earth. A special attention is paid to the investigation of transient stages between the physico-chemical and biological bases of self-assembly, including experimental models and paleontological results. The theory of coacervate-in-coacervate is discussed from the point of view of evolution of first procaryotic cells. Many of the high developed structures of the contemporary cells, such as ribosomes, chromosomes, lipid membranes, some other organelles etc., are claimed to posses a rudimentary polyionic coacervate character.

Biological Evolution↗