A molecular analysis of PGE receptor (EP) expression on normal and transformed B lymphocytes: Coexpression of EP1, EP2, EP and EP4

Eric R. Fedyk, John M. Ripper, Deborah M. Brown, Richard P. Phipps

Research output: Contribution to journalArticle

49 Scopus citations

Abstract

The E-series prostaglandins (PGEs) are complex lipid regulators of B lymphocyte function. They inhibit the growth of certain B lymphoma lines. We report that heterogeneity with respect to PGE-induced growth inhibition correlates with the maturation state of the B cell lines. Specifically, the pre-B cell line 70Z/3 and the immature lymphoma CH31 are extremely sensitive to PGE2. To a lesser degree, other immature lymphomas (CH33, ECH408.1 and WEHI-231) are sensitive to PGE2. More mature lymphomas (BAL-17, CH12 and CH27) and fully differentiated myelomas (J558 and MOPC-315) are insensitive to PGE2. It is unknown what subtype of PGE receptor(s) (EPs) are expressed by B lymphocytes. It is also unknown if modulation of EP receptor expression could account for the differences in the sensitivity of these B cell lines to PGE2. To investigate these issues, reverse transcriptase polymerase chain reaction, Northern blot and DNA sequencing analyses were employed to obtain a definitive EP receptor subtype profile for these B cell lines, and for normal splenic B lymphocytes. Both normal and transformed B lymphocytes express mRNA encoding EP1, EP and EP4 subtypes of PGE receptors. The B lineage cells do not express EP nor EP mRNA. The B cell lines are clonal, indicating that EP1, EP and EP4 mRNA are coexpressed. Surprisingly, quantitative differences in basal EP1, EP and EP4 expression were not observed between B cell lines despite their differing susceptibilities to PGE-induced growth inhibition. Conversely, the polyclonal activator LPS selectively upregulates EP4 mRNA expression in the mature B cell line CH12, but not in the LPS-sensitive pre-B cell line, 70Z/3. The activator LPS does not affect EP1 nor EP mRNA expression. Treatment with dbcAMP, an analog of cAMP, mimics PGE-induced growth inhibition indicating that Gs-coupled EP2 and/or EP4 receptors mediate this inhibitory signal. Indeed, EP2 agonists mimic PGE2-induced growth inhibition unlike IP, EP1 and EP3-selective agonists. These data indicate that EP2 receptors are sufficient for mediating PGE-induced growth inhibition of susceptible B lineage cells.

Original languageEnglish (US)
Pages (from-to)33-45
Number of pages13
JournalMolecular Immunology
Volume33
Issue number1
DOIs
StatePublished - Jan 1996

Keywords

  • B lymphocyte
  • B lymphoma
  • EP
  • EP
  • EP
  • EP
  • Growth inhibition
  • LPS
  • Mouse
  • Myeloma
  • PGE
  • Prostaglandin

ASJC Scopus subject areas

  • Immunology
  • Molecular Biology

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