Hongxia Sun1, Junfeng Xiang2, Yunhua Shi3, Qianfan Yang2, Aijiao Guan2, Qian Li2, Lijia Yu3, Qian Shang2, Hong Zhang2, Yalin Tang4, Guangzhi Xu2. 1. Beijing National Laboratory for Molecular Sciences, State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, PR China. Electronic address: hongxsun@iccas.ac.cn. 2. Beijing National Laboratory for Molecular Sciences, State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, PR China. 3. Beijing National Laboratory for Molecular Sciences, State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, PR China; University of Chinese Academy of Sciences, Yuquan Road 19(A), Shijingshan District, Beijing 100049, PR China. 4. Beijing National Laboratory for Molecular Sciences, State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, PR China. Electronic address: tangyl@iccas.ac.cn.
Abstract
BACKGROUND: A new G-quadruplex structure located in the B-cell CLL/lymphoma 2 (Bcl-2) P1 promoter and its physiological function related to Bcl-2 transcription have been studied to find a potential anticancer therapeutic target. METHODS: Absorption, polyacrylamide gel electrophoresis, fluorescence, circular dichroism, and nuclear magnetic resonance spectra have been employed to determine G-quadruplex structure and the interaction between G-quadruplex and phenanthrolin-dicarboxylate. Real time polymerase chain reaction and luciferase assay were done to assess the physiological function of the G-quadruplex structure. RESULTS: The UV-melting and polyacrylamide gel electrophoresis studies show that the p32 DNA sequence forms an intramolecular G-quadruplex structure. Circular dichroism and nuclear magnetic resonance spectra indicate that the G-quadruplex is a hybrid-type structure with four G-tetrads. Fluorescence spectra show that a phenanthroline derivative has a higher binding affinity for p32 G-quadruplex than duplex. Further circular dichroism and nuclear magnetic resonance studies indicate that the phenanthroline derivative can regulate p32 G-quadruplex conformation. Real time polymerase chain reaction and luciferase assays show that the phenanthroline derivative has down-modulated Bcl-2 transcription activity in a concentration-dependent manner. However, no such effect was observed when p32 G-quadruplex was denatured through base mutation. CONCLUSION: The newly identified G-quadruplex located in the P1 promoter of Bcl-2 oncogene is intimately related with Bcl-2 transcription activity, which may be a promising anticancer therapeutic target. GENERAL SIGNIFICANCE: The newly identified G-quadruplex in the Bcl-2 P1 promoter may be a novel anticancer therapeutic target.
BACKGROUND: A new G-quadruplex structure located in the B-cell CLL/lymphoma 2 (Bcl-2) P1 promoter and its physiological function related to Bcl-2 transcription have been studied to find a potential anticancer therapeutic target. METHODS: Absorption, polyacrylamide gel electrophoresis, fluorescence, circular dichroism, and nuclear magnetic resonance spectra have been employed to determine G-quadruplex structure and the interaction between G-quadruplex and phenanthrolin-dicarboxylate. Real time polymerase chain reaction and luciferase assay were done to assess the physiological function of the G-quadruplex structure. RESULTS: The UV-melting and polyacrylamide gel electrophoresis studies show that the p32 DNA sequence forms an intramolecular G-quadruplex structure. Circular dichroism and nuclear magnetic resonance spectra indicate that the G-quadruplex is a hybrid-type structure with four G-tetrads. Fluorescence spectra show that a phenanthroline derivative has a higher binding affinity for p32 G-quadruplex than duplex. Further circular dichroism and nuclear magnetic resonance studies indicate that the phenanthroline derivative can regulate p32 G-quadruplex conformation. Real time polymerase chain reaction and luciferase assays show that the phenanthroline derivative has down-modulated Bcl-2 transcription activity in a concentration-dependent manner. However, no such effect was observed when p32 G-quadruplex was denatured through base mutation. CONCLUSION: The newly identified G-quadruplex located in the P1 promoter of Bcl-2 oncogene is intimately related with Bcl-2 transcription activity, which may be a promising anticancer therapeutic target. GENERAL SIGNIFICANCE: The newly identified G-quadruplex in the Bcl-2 P1 promoter may be a novel anticancer therapeutic target.
Authors: Stephan A Ohnmacht; Chiara Marchetti; Mekala Gunaratnam; Rachael J Besser; Shozeb M Haider; Gloria Di Vita; Helen L Lowe; Maria Mellinas-Gomez; Seckou Diocou; Mathew Robson; Jiri Šponer; Barira Islam; R Barbara Pedley; John A Hartley; Stephen Neidle Journal: Sci Rep Date: 2015-06-16 Impact factor: 4.379