Inhibition of NUPR1-Karyopherin β1 Binding Increases Anticancer Drug Sensitivity

• Published in: International journal of molecular sciences 2021-03, Vol.22 (6), p.2794
• Main Authors: Park, Chanhee, Oh, Jiwon, Lee, Won Mo, Koh, Hye Ran, Sohn, Uy Dong, Ham, Seung Wook, Oh, Kyungsoo
• Format: Article
• Language: English
• Subjects: Acrylamides - chemistry; Acrylamides - pharmacology; Active Transport, Cell Nucleus - drug effects; Antibiotics, Antineoplastic - chemistry; Antibiotics, Antineoplastic - pharmacology; Basic Helix-Loop-Helix Transcription Factors - metabolism; Benzothiazoles - chemistry; Benzothiazoles - pharmacology; beta Karyopherins - metabolism; Cell Line, Tumor; Cell Nucleus - drug effects; Cell Nucleus - metabolism; Cell Survival - drug effects; combination; Doxorubicin - chemistry; Doxorubicin - pharmacology; drug sensitivity; Drug Synergism; Humans; KPNB1; MCF-7 Cells; Microscopy, Confocal; Molecular Structure; Neoplasm Proteins - metabolism; NUPR1; protein binding; Protein Binding - drug effects
• ISSN: 1422-0067; 1661-6596; 1422-0067
• DOI: 10.3390/ijms22062794

Nuclear protein-1 (NUPR1, also known as p8/Com-1) is a transcription factor involved in the regulation of cellular stress responses, including serum starvation and drug stimulation. We investigated the mechanism of NUPR1 nuclear translocation involving karyopherin β1 (KPNB1), using a single-molecule binding assay and confocal microscopy. The cellular effects associated with NUPR1-KPNB1 inhibition were investigated by gene expression profiling and cell cycle analysis. The single-molecule binding assay revealed that KPNB1 bound to NUPR1 with a binding affinity of 0.75 nM and that this binding was blocked by the aminothiazole ATZ-502. Following doxorubicin-only treatment, NUPR1 was translocated to the nucleus in more than 90% and NUPR1 translocation was blocked by the ATZ-502 combination treatment in MDA-MB-231 with no change in NUPR1 expression, providing strong evidence that NUPR1 nuclear translocation was directly inhibited by the ATZ-502 treatment. Inhibition of KPNB1 and NUPR1 binding was associated with a synergistic anticancer effect (up to 19.6-fold) in various cancer cell lines. NUPR1-related genes were also downregulated following the doxorubicin-ATZ-502 combination treatment. Our current findings clearly demonstrate that NUPR1 translocation into the nucleus requires karyopherin β1 binding. Inhibition of the KPNB1 and NUPR1 interaction may constitute a new cancer therapeutic approach that can increase the drug efficacy while reducing the side effects.