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Updated: Jan 28, 2026
Biotinylated Cell-penetrating Peptides to Study Intracellular Protein-protein Interactions
Published on: December 20, 2017
Design of CK2β-Mimicking Peptides as Tools To Study the CK2α/CK2β Interaction in Cancer Cells
Dirk Lindenblatt1, Mareike Horn1, Claudia Götz2
1Department of Chemistry, Institute of Biochemistry, University of Cologne, Zülpicher Straße 47, 50674, Cologne, Germany.
Abstract:
The ubiquitously expressed Ser/Thr kinase CK2 is a key regulator in a variety of key processes in normal and malignant cells. Due to its distinctive anti-apoptotic and tumor-driving properties, elevated levels of CK2 have frequently been found in tumors of different origin. In recent years, development of CK2 inhibitors has largely been focused on ATP-competitive compounds; however, targeting the CK2α/CK2β interface has emerged as a further concept that might avoid selectivity issues. To address the CK2 subunit interaction site, we have synthesized halogenated CK2β-mimicking cyclic peptides modified with the cell-penetrating peptide sC18 to mediate cellular uptake. We investigated the binding of the resulting chimeric peptides to recombinant human CK2α using a recently developed fluorescence anisotropy assay. The iodinated peptide sC18-I-Pc was identified as a potent CK2α ligand (Ki =0.622 μm). It was internalized in cells to a high extent and exhibited significant cytotoxicity toward cancerous HeLa cells (IC50 =37 μm) in contrast to non-cancerous HEK-293 cells. The attractive features and functionalities of sC18-I-Pc offer the opportunity for further improvement.
Insights
Novel peptide inhibitors targeting the CK2 kinase show promise for cancer therapy. The synthesized sC18-I-Pc peptide effectively targets cancer cells, offering a new strategy against tumors.
Area of Science:
- Biochemistry
- Molecular Biology
- Medicinal Chemistry
Background:
- Protein kinase CK2 (Casein Kinase 2) is crucial for cell regulation and often overexpressed in cancers.
- Targeting the CK2α/CK2β subunit interface offers an alternative to ATP-competitive inhibitors for improved selectivity.
- Developing cell-penetrating peptides can enhance drug delivery and efficacy.
Purpose of the Study:
- To design and synthesize novel CK2 inhibitors targeting the CK2α/CK2β interface.
- To evaluate the binding affinity, cellular uptake, and cytotoxicity of these peptide inhibitors.
- To explore the therapeutic potential of CK2β-mimicking peptides in cancer treatment.
Main Methods:
- Synthesis of halogenated, cyclic CK2β-mimicking peptides conjugated with the cell-penetrating peptide sC18.
- Investigation of peptide binding to recombinant human CK2α using a fluorescence anisotropy assay.
- Assessment of cellular internalization and cytotoxicity against cancerous (HeLa) and non-cancerous (HEK-293) cell lines.
Main Results:
- The iodinated peptide sC18-I-Pc demonstrated potent binding to CK2α with a Ki of 0.622 μm.
- sC18-I-Pc exhibited high cellular internalization.
- Significant cytotoxicity was observed in HeLa cancer cells (IC50 = 37 μm) but not in HEK-293 cells.
Conclusions:
- The peptide sC18-I-Pc effectively inhibits CK2α and shows selective cytotoxicity towards cancer cells.
- This CK2β-mimicking peptide represents a promising lead compound for developing targeted cancer therapies.
- Further optimization of sC18-I-Pc may lead to enhanced therapeutic efficacy.
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