A G316A Polymorphism in the Ornithine Decarboxylase Gene Promoter Modulates MYCN-Driven Childhood Neuroblastoma

Abstract

Ornithine decarboxylase (ODC1), a critical regulatory enzyme in polyamine biosynthesis, is a direct transcriptional target of MYCN, amplification of which is a powerful marker of aggressive neuroblastoma. A single nucleotide polymorphism (SNP), G316A, within the first intron of ODC1, results in genotypes wildtype GG, and variants AG/AA. CRISPR-cas9 technology was used to investigate the effects of AG clones from wildtype MYCN-amplified SK-N-BE(2)-C cells and the effect of the SNP on MYCN binding, and promoter activity was investigated using EMSA and luciferase assays. AG clones exhibited decreased ODC1 expression, growth rates, and histone acetylation and increased sensitivity to ODC1 inhibition. MYCN was a stronger transcriptional regulator of the ODC1 promoter containing the G allele, and preferentially bound the G allele over the A. Two neuroblastoma cohorts were used to investigate the clinical impact of the SNP. In the study cohort, the minor AA genotype was associated with improved survival, while poor prognosis was associated with the GG genotype and AG/GG genotypes in MYCN-amplified and non-amplified patients, respectively. These effects were lost in the GWAS cohort. We have demonstrated that the ODC1 G316A polymorphism has functional significance in neuroblastoma and is subject to allele-specific regulation by the MYCN oncoprotein.

Phase 1 study of high-dose DFMO, celecoxib, cyclophosphamide and topotecan for patients with relapsed neuroblastoma: a New Approaches to Neuroblastoma Therapy trial

“…Responses were seen in patients with MYCN amplified and non-amplified tumors. Both functional ODC1 SNP risk alleles, G316 (rs2302615) [ 41 ] and T263 (rs2302616), were overrepresented in our relapsed/refractory patient cohort compared with population data though our study is underpowered to assess correlation with response or toxicity. In patients treated at the MTD of 6750 mg/m 2 /day, the mean trough DFMO concentration was >70 µmol/L, above that obtained in TH-MYCN mice treated with 1% DFMO in preclinical studies showing anti-tumor efficacy.…”

Acupuncture Synergized With Bortezomib Improves Survival of Multiple Myeloma Mice via Decreasing Metabolic Ornithine

“…Arginine metabolism is considered to be an important regulator in controlling immune response ( 48 , 49 ), inhibiting antitumor immune response ( 50 , 51 ), and promoting tumor development ( 34 , 52 ). Ornithine is decarboxylated by ODC1 to produce putrescine, which is the rate-limiting step in polyamine biosynthesis ( 53 , 54 ). Combined with cellular proliferation results ( Figures 7A–D ), we speculate that inhibiting arginine-ornithine metabolism can reduce ornithine content, thus decrease polyamine biosynthesis.…”

Polyamines and Their Metabolism: From the Maintenance of Physiological Homeostasis to the Mediation of Disease

“…Genetic polymorphisms in ODC genes are also associated with a number of cancers including neuroblastomas, as well as gastric, colorectal, breast and prostate cancers [ 144 , 145 , 146 , 147 , 148 ]. Yet, maintaining physiological levels of ODC is vital for cell growth and function, as demonstrated through in vitro studies [ 134 , 135 ].…”