Retinoic-acid-resistant neuroblastoma cell lines show altered MYC regulation and high sensitivity to fenretinide

Med Pediatr Oncol. 2000 Dec;35(6):597-602. doi: 10.1002/1096-911x(20001201)35:6<597::aid-mpo23>;2-b.


Background: High-dose, pulse-13-cis-retinoic acid (13-cis-RA) given after intensive cytotoxic therapy improves event-free survival for high-risk neuroblastoma (NB), but more than 50% of patients have tumor recurrence.

Procedure: We conducted multistep selection for resistance to all-trans-retinoic acid (ATRA) in NB cell lines with (SMS-KCNR and LA-N-5) or without (SMS-LHN) MYCN genomic amplification.

Results: After 12 exposures to 10 microM ATRA, the two MYCN-amplified cell lines (KCNR 12X RR and LA-N-5 12X RR) showed partial resistance to the cytostatic/differentiation effects of ATRA; complete resistance was seen in LHN 12X RR. ATRA-selected cells showed general RA resistance (cross-resistance to 13-cis-RA). Transient (KCNR 12 X RR, LA-N-5 12X RR) or sustained (LHN 12X RR) novel overexpression of c-myc was associated with RA resistance. RA-insensitive overexpression of MYCN by transduction in SMS-LHN also conferred RA resistance. Both parental and RA-resistant lines showed 2-4 logs of cell kill in response to N-(4-hydroxyphenyl)retinamide (4- HPR, fenretinide). Compared to parental lines, 4-HPR achieved 1-3 log greater cell kills in RA-resistant LHN 12X RR, LA-N-5 12X RR, KCNR 12X RR, and MYCN-transduced SMS-LHN or SK-N-RA. NB cell lines (n = 26) from 21 different patients showed that 16 of 26 (62%) were sensitive to 4-HPR (LC(90) < 10 microM), including lines established at relapse after myeloablative and/or 13-cis-RA therapy.

Conclusion: Thus, RA-resistant NB cell lines can be sensitive (and in some cases collaterally hypersensitive) to 4-HPR.

Publication types

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

MeSH terms

  • Antineoplastic Agents / therapeutic use*
  • Drug Resistance, Neoplasm
  • Fenretinide / therapeutic use*
  • Gene Expression Regulation, Neoplastic*
  • Genes, myc / genetics*
  • Humans
  • Neuroblastoma / drug therapy*
  • Tretinoin / therapeutic use*
  • Tumor Cells, Cultured


  • Antineoplastic Agents
  • Fenretinide
  • Tretinoin