Supplementary Figure S1. MYCN-amplified neuroblastoma cell lines are addicted to MYCN. Supplementary Figure S2. Cytotoxic evaluation of PI polyamides targeting the MYCN gene. Supplementary Figure S3. Direct alkylation of the targeted DNA of MYCN gene. Supplementary Figure S4. MYCN-A3 and MYCN-A4 inhibit MYCN expression and cell proliferation in MYCN-amplified neuroblastoma cell lines. Supplementary Figure S5. Global impact of MYCN-A3 on gene expression in MYCN-amplified neuroblastoma cells is comparable to that of CRISPR/Cas9 targeting MYCN. Supplementary Figure S6. MYCN-A3 induces cell cycle arrest and the expression levels of p53 family genes in neuroblastoma cell lines. Supplementary Figure S7. MYCN-A3 suppresses tumor growth in human neuroblastoma xenograft mouse models. Supplementary Figure S8. Pharmacological effects of MYCN-A3 on human MYCN-amplified neuroblastoma xenograft models in vivo. Supplementary Figure S9. MYCN-A3 affects the MYCN gene loci and not non-targeted gene loci.
Funding
Japan Agency for Medical Research and Development
MEXT
Takeda Science Foundation
Princess Takamatsu Cancer Research Fund
JSPS
AMED
ARTICLE ABSTRACT
Amplification of MYCN plays a pivotal role in multiple types of tumors and correlates with poor prognosis in high-risk neuroblastoma. Despite recent advances in the treatment of neuroblastoma, no approaches directly target the master oncogene MYCN. Difficulties in targeting the MYCN protein inspired us to develop a new gene-level–inhibitory strategy using a sequence-specific gene regulator. Here, we generated a MYCN-targeting pyrrole-imidazole (PI) polyamide, MYCN-A3, which directly binds to and alkylates DNA at homing motifs within the MYCN transcript. Pharmacologic suppression of MYCN inhibited the proliferation of cancer cells harboring MYCN amplification compared with MYCN nonamplified cancer cells. In neuroblastoma xenograft mouse models, MYCN-A3 specifically downregulated MYCN expression and suppressed tumor progression with no detectable adverse effects and resulted in prolonged overall survival. Moreover, treatment with MYCN-A3, but not MYCN nontargeting PI polyamide, precipitated a copy number reduction of MYCN in neuroblastoma cells with MYCN amplification. These findings suggest that directly targeting MYCN with MYCN-A3 is a novel therapeutic approach to reduce copy number of the MYCN gene for MYCN-amplified neuroblastoma.
This study presents a novel approach to drugging an amplified oncogene by showing that targeting gene amplification of MYCN suppresses MYCN expression and neuroblastoma growth.
