Differential sensitivity of chemoresistant neuroblastoma subtypes to MAPK-targeted treatment correlates with ERK, p53 expression, and signaling response to U0126

Andrew C. Eppstein, John A. Sandoval, Patrick J. Klein, Heather A. Woodruff, Jay L. Grosfeld, Robert J. Hickey, Linda H. Malkas, C. Max Schmidt

Research output: Contribution to journalArticle

17 Scopus citations

Abstract

Purpose: Neuroblastoma tumors are comprised of neuroblastic (N), substrate-adherent (S), and intermediate (I) cells. Because cell growth and differentiation often involve p44/p42 mitogen-activated protein kinase (MAPK) pathway signaling, we explored MAPK signaling and growth response in three NB cell types after MAPK kinase (MEK) inhibition to evaluate the feasibility of MAPK-targeted treatment strategies. Methods: Three human NB cell cultures, SH-SY5Y (N-type), BE(2)-C (I-type), and SK-N-AS (S-type), were treated in monolayer cultures with increasing concentrations of the MEK inhibitor U0126. MAPK pathway intermediates MEK and ERK, their activated (phosphorylated) forms p-MEK and p-ERK, and p53 expression were assessed by Western blot at 1 and 24 hours. At 72 hours, cell counts determined growth inhibition and DNA fragmentation ELISA assessed apoptosis. Results: Among all three lines, total ERK and MEK expression were unaffected by U0126. However, constitutive total ERK and p53 expression were significantly greater in BE(2)-C (I-type) cells than in SH-SY5Y (N-type) and SK-N-AS (S-type). Active ERK (p-ERK) levels decreased in dose response to U0126 at 1 and 24 hours in all lines. Conversely, p-MEK levels increased with increasing U0126 concentrations at 1 hour in SH-SY5Y (N-type) and at 24 hours in all lines. BE(2)-C (I-type) cell counts decreased in concentration-dependent fashion with U0126, whereas SH-SY5Y (N-type) and SK-N-AS (S-type) showed a biphasic response with increased cell counts at 1 μmol/L U0126 and slightly decreased cell counts at 10 μmol/L U0126. Conclusion: This study demonstrates that BE(2)-C (I-type) cells exhibit greater constitutive total ERK and p53 expression than SH-SY5Y (N-type) and SK-N-AS (S-type). Although all three lines exhibit p-ERK decreases with MEK inhibition, only BE(2)-C (I-type) cells significantly decrease their proliferation with U0126 treatment. Although MEK inhibition holds promise in targeting I-type NB cells, successfully treating this heterogeneous tumor may require combining agents against N- and S-type cells.

Original languageEnglish (US)
Pages (from-to)252-259
Number of pages8
JournalJournal of Pediatric Surgery
Volume41
Issue number1
DOIs
StatePublished - Jan 1 2006

    Fingerprint

Keywords

  • MAPK resistance
  • Mitogen-activated protein kinase (MAPK)
  • N-type, S-type, I-type
  • Neuroblastoma

ASJC Scopus subject areas

  • Surgery

Cite this