Synthetic bryostatin analogues activate the RasGRP1 signaling pathway

J Med Chem. 2004 Dec 16;47(26):6638-44. doi: 10.1021/jm0495069.

Abstract

The functional properties of four diacylglycerol (DAG) analogues were compared using cell-signaling assays based on the protein RasGRP1, a DAG-regulated Ras activator. Compounds 1 and 2, synthetic analogues of bryostatin 1, were compared to authentic bryostatin 1 and phorbol 12-myristate-13-acetate (PMA). The two "bryologues" were able to activate RasGRP1 signaling rapidly in cultured cells and isolated mouse thymocytes. They elicited expression of the T cell activation marker CD69 in human T cells. DAG analogues promptly recruited RasGRP1 to cell membranes, but they did not induce RasGRP1 proteolysis. Bryostatin 1 and compounds 1 and 2 appeared to be less potent than PMA at inducing aggregation of mouse thymocytes, a PKC-dependent, RasGRP1-independent response. In addition to sharing potential anticancer properties with bryostatin 1, compounds 1 and 2 might be clinically useful as modulators of the immune system.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Antigens, CD / biosynthesis
  • Antigens, Differentiation, T-Lymphocyte / biosynthesis
  • Bryostatins
  • Cell Aggregation / drug effects
  • Cell Membrane / metabolism
  • Cells, Cultured
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / physiology*
  • Extracellular Signal-Regulated MAP Kinases / metabolism
  • Guanine Nucleotide Exchange Factors / genetics
  • Guanine Nucleotide Exchange Factors / physiology*
  • Humans
  • Immunologic Factors / chemical synthesis*
  • Immunologic Factors / chemistry
  • Immunologic Factors / pharmacology
  • Lactones / chemical synthesis*
  • Lactones / chemistry
  • Lactones / pharmacology
  • Lectins, C-Type
  • Macrolides
  • Mice
  • Mutation
  • Phosphorylation
  • Protein Kinase C / physiology
  • Protein Transport / drug effects
  • Signal Transduction / drug effects
  • T-Lymphocytes / drug effects
  • T-Lymphocytes / metabolism
  • T-Lymphocytes / physiology
  • Tetradecanoylphorbol Acetate / pharmacology
  • Thymus Gland / cytology
  • Transfection

Substances

  • Antigens, CD
  • Antigens, Differentiation, T-Lymphocyte
  • Bryostatins
  • CD69 antigen
  • DNA-Binding Proteins
  • Guanine Nucleotide Exchange Factors
  • Immunologic Factors
  • Lactones
  • Lectins, C-Type
  • Macrolides
  • RASGRP1 protein, human
  • Rasgrp1 protein, mouse
  • bryostatin 1
  • Protein Kinase C
  • Extracellular Signal-Regulated MAP Kinases
  • Tetradecanoylphorbol Acetate