Metabolic characteristics of 13-cis-retinoic acid (isotretinoin) and anti-tumour activity of the 13-cis-retinoic acid metabolite 4-oxo-13-cis-retinoic acid in neuroblastoma.

Abstract

BACKGROUND AND PURPOSE:

Isotretinoin (13-cis-retinoic acid; 13-cRA) is a differentiation inducer used to treat minimal residual disease after myeloablative therapy for high-risk neuroblastoma. However, more than 40% of children develop recurrent disease during or after 13-cRA treatment. The plasma concentrations of 13-cRA in earlier studies were considered subtherapeutic while 4-oxo-13-cis-RA (4-oxo-13-cRA), a metabolite of 13-cRA considered by some investigators as inactive, were greater than threefold higher than 13-cRA. We sought to define the metabolic pathways of 13-cRA and investigated the anti-tumour activity of its major metabolite, 4-oxo-13-cRA.

EXPERIMENTAL APPROACH:

Effects of 13-cRA and 4-oxo-13-cRA on human neuroblastoma cell lines were assessed by DIMSCAN and flow cytometry for cell proliferation, MYCN down-regulation by reverse transcription PCR and immunoblotting, and neurite outgrowth by confocal microscopy. 13-cRA metabolism was determined using tandem MS in human liver microsomes and in patient samples.

KEY RESULTS:

Six major metabolites of 13-cRA were identified in patient samples. Of these, 4-oxo-13-cRA was the most abundant, and 4-oxo-13-cRA glucuronide was also detected at a higher level in patients. CYP3A4 was shown to play a major role in catalysing 13-cRA to 4-oxo-13-cRA. In human neuroblastoma cell lines, 4-oxo-13-cRA and 13-cRA were equi-effective at inducing neurite outgrowth, inhibiting proliferation, decreasing MYCN mRNA and protein, and increasing the expression of retinoic acid receptor-β mRNA and protein levels.

CONCLUSIONS AND IMPLICATIONS:

We showed that 4-oxo-13-cRA is as active as 13-cRA against neuroblastoma cell lines. Plasma levels of both 13-cRA and 4-oxo-13-cRA should be evaluated in pharmacokinetic studies of isotretinoin in neuroblastoma.

• Authors: Poonam Sonawane, Hwang Eui Cho, Ashujit Tagde, Dattesh Verlekar, Alice L Yu, C Patrick Reynolds, Min H Kang
• Journal: British journal of pharmacology (Br J Pharmacol) Vol. 171 Issue 23 Pg. 5330-44 (Dec 2014) ISSN: 1476-5381 [Electronic] England
• PMID: 25039756 (Publication Type: Clinical Trial, Phase III, Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't)
• Copyright: © 2014 The British Pharmacological Society.

Chemical References

• Antineoplastic Agents
• MYCN protein, human
• N-Myc Proto-Oncogene Protein
• Nuclear Proteins
• Oncogene Proteins
• RNA, Messenger
• Receptors, Retinoic Acid
• retinoic acid receptor beta
• 4-oxoretinoic acid
• Tretinoin
• CYP3A5 protein, human
• Cytochrome P-450 CYP3A
• CYP3A4 protein, human
• Isotretinoin

Topics

• Animals
• Antineoplastic Agents (blood, pharmacokinetics, pharmacology)
• Cell Line, Tumor
• Cell Proliferation (drug effects)
• Central Nervous System Neoplasms (blood, drug therapy, metabolism)
• Chromatography, High Pressure Liquid
• Cytochrome P-450 CYP3A (metabolism)
• Humans
• Isotretinoin (blood, pharmacokinetics, pharmacology)
• Mice, Inbred BALB C
• Microsomes (drug effects, metabolism)
• N-Myc Proto-Oncogene Protein
• Neurites (drug effects)
• Neuroblastoma (blood, drug therapy, metabolism)
• Nuclear Proteins (genetics, metabolism)
• Oncogene Proteins (genetics, metabolism)
• RNA, Messenger (metabolism)
• Receptors, Retinoic Acid (genetics, metabolism)
• Tandem Mass Spectrometry
• Tretinoin (analogs & derivatives, blood, pharmacology)