1. The novel BH3 α-helix mimetic JY-1-106 induces apoptosis in a subset of cancer cells (lung cancer, colon cancer and mesothelioma) by disrupting Bcl-xL and Mcl-1 protein-protein interactions with Bak
- Author
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Paul T. Wilder, Roy W. Smythe, M. Karen Newell-Rogers, Xiaobo Cao, Kwan-Young Jung, Jeremy L. Yap, Arun Rai, Weihua Jiang, Steven Fletcher, Wenbo Yu, Dan Jupitor, Alexander D. MacKerell, Harry T. Papaconstantinou, Richard P Tubin, Chander Peddaboina, Kenno Vanommeslaeghe, Chemistry, Pathology/molecular and cellular medicine, and Analytical Chemistry and Pharmaceutical Technology
- Subjects
Mesothelioma ,Cancer Research ,Programmed cell death ,BH3 mimetic ,Lung Neoplasms ,Immunoprecipitation ,bcl-X Protein ,Bcl-xL ,Antineoplastic Agents ,Apoptosis ,Molecular Dynamics Simulation ,Protein Structure, Secondary ,Mice ,Nude mouse ,Cell Line, Tumor ,para-Aminobenzoates ,Animals ,Humans ,Cancer ,A549 cell ,biology ,Research ,Molecular Mimicry ,Mcl-1 ,biology.organism_classification ,Ligand (biochemistry) ,Xenograft Model Antitumor Assays ,Cell biology ,Protein Structure, Tertiary ,bcl-2 Homologous Antagonist-Killer Protein ,Oncology ,Cancer cell ,Benzamides ,Colonic Neoplasms ,biology.protein ,Cancer research ,Molecular Medicine ,Myeloid Cell Leukemia Sequence 1 Protein ,Small molecule inhibitor ,Bcl-2 Homologous Antagonist-Killer Protein - Abstract
Background It has been shown in many solid tumors that the overexpression of the pro-survival Bcl-2 family members Bcl-2/Bcl-xL and Mcl-1 confers resistance to a variety of chemotherapeutic agents. We designed the BH3 α-helix mimetic JY-1-106 to engage the hydrophobic BH3-binding grooves on the surfaces of both Bcl-xL and Mcl-1. Methods JY-1-106–protein complexes were studied using molecular dynamics (MD) simulations and the SILCS methodology. We have evaluated the in vitro effects of JY-1-106 by using a fluorescence polarization (FP) assay, an XTT assay, apoptosis assays, and immunoprecipitation and western-blot assays. A preclinical human cancer xenograft model was used to test the efficacy of JY-1-106 in vivo. Results MD and SILCS simulations of the JY-1-106–protein complexes indicated the importance of the aliphatic side chains of JY-1-106 to binding and successfully predicted the improved affinity of the ligand for Bcl-xL over Mcl-1. Ligand binding affinities were measured via an FP assay using a fluorescently labeled Bak-BH3 peptide in vitro. Apoptosis induction via JY-1-106 was evidenced by TUNEL assay and PARP cleavage as well as by Bax–Bax dimerization. Release of multi-domain Bak from its inhibitory binding to Bcl-2/Bcl-xL and Mcl-1 using JY-1-106 was detected via immunoprecipitation (IP) western blotting. At the cellular level, we compared the growth proliferation IC50s of JY-1-106 and ABT-737 in multiple cancer cell lines with various Bcl-xL and Mcl-1 expression levels. JY-1-106 effectively induced cell death regardless of the Mcl-1 expression level in ABT-737 resistant solid tumor cells, whilst toxicity toward normal human endothelial cells was limited. Furthermore, synergistic effects were observed in A549 cells using a combination of JY-1-106 and multiple chemotherapeutic agents. We also observed that JY-1-106 was a very effective agent in inducing apoptosis in metabolically stressed tumors. Finally, JY-1-106 was evaluated in a tumor-bearing nude mouse model, and was found to effectively repress tumor growth. Strong TUNEL signals in the tumor cells demonstrated the effectiveness of JY-1-106 in this animal model. No significant side effects were observed in mouse organs after multiple injections. Conclusions Taken together, these observations demonstrate that JY-1-106 is an effective pan-Bcl-2 inhibitor with very promising clinical potential.
- Published
- 2013