Chemical Biology Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702-1201, USA.
Pediatric Oncology Branch, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892-1928, USA.
Nucleic Acids Res. 2021 Aug 20;49(14):7856-7869. doi: 10.1093/nar/gkab594.
The MYCN gene encodes the transcription factor N-Myc, a driver of neuroblastoma (NB). Targeting G-quadruplexes (G4s) with small molecules is attractive strategy to control the expression of undruggable proteins such as N-Myc. However, selective binders to G4s are challenging to identify due to the structural similarity of many G4s. Here, we report the discovery of a small molecule ligand (4) that targets the noncanonical, hairpin containing G4 structure found in the MYCN gene using small molecule microarrays (SMMs). Unlike many G4 binders, the compound was found to bind to a pocket at the base of the hairpin region of the MYCN G4. This compound stabilizes the G4 and has affinity of 3.5 ± 1.6 μM. Moreover, an improved analog, MY-8, suppressed levels of both MYCN and MYCNOS (a lncRNA embedded within the MYCN gene) in NBEB neuroblastoma cells. This work indicates that the approach of targeting complex, hybrid G4 structures that exist throughout the human genome may be an applicable strategy to achieve selectivity for targeting disease-relevant genes including protein coding (MYCN) as well as non-coding (MYCNOS) gene products.
MYCN 基因编码转录因子 N-Myc，是神经母细胞瘤（NB）的驱动基因。用小分子靶向 G-四链体（G4s）是一种控制 N-Myc 等难以成药蛋白表达的有吸引力的策略。然而，由于许多 G4s 的结构相似，因此难以识别选择性结合 G4s 的小分子。在这里，我们报告了一种小分子配体（4）的发现，该配体使用小分子微阵列（SMMs）针对 MYCN 基因中存在的非典型发夹状 G4 结构。与许多 G4 结合物不同，该化合物被发现结合到 MYCN G4 发夹区域底部的一个口袋中。该化合物稳定 G4，亲和力为 3.5±1.6μM。此外，一种改进的类似物 MY-8，可抑制 NBEB 神经母细胞瘤细胞中 MYCN 和 MYCNOS（嵌入 MYCN 基因内的长非编码 RNA）的水平。这项工作表明，针对存在于整个人类基因组中的复杂、混合 G4 结构的方法可能是一种可行的策略，可实现针对包括编码蛋白（MYCN）和非编码（MYCNOS）基因产物在内的与疾病相关基因的选择性。
