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.

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TitleThe 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.
Publication TypeJournal Article
Year of Publication2013
AuthorsCao, X, Yap, JL, M Newell-Rogers, K, Peddaboina, C, Jiang, W, Papaconstantinou, HT, Jupitor, D, Rai, A, Jung, K-Y, Tubin, RP, Yu, W, Vanommeslaeghe, K, Wilder, PT, Mackerell, AD, Fletcher, S, Smythe, RW
JournalMol Cancer
Volume12
Issue1
Pagination42
Date Published2013 May 16
ISSN1476-4598
KeywordsAnimals, Antineoplastic Agents, Apoptosis, bcl-2 Homologous Antagonist-Killer Protein, bcl-X Protein, Benzamides, Cell Line, Tumor, Colonic Neoplasms, Humans, Lung Neoplasms, Mesothelioma, Mice, Molecular Dynamics Simulation, Molecular Mimicry, Myeloid Cell Leukemia Sequence 1 Protein, para-Aminobenzoates, Protein Structure, Secondary, Protein Structure, Tertiary, Xenograft Model Antitumor Assays
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.

DOI10.1186/1476-4598-12-42
Alternate JournalMol. Cancer
PubMed ID23680104
PubMed Central IDPMC3663763