Related Experiment Video
Updated: Jun 27, 2026
Biotinylated Cell-penetrating Peptides to Study Intracellular Protein-protein Interactions
Published on: December 20, 2017
Targeting a c-Myc inhibitory polypeptide to specific intracellular compartments using cell penetrating peptides
Gene L Bidwell1, Aisha N Davis, Drazen Raucher
1Department of Biochemistry, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS 39216, USA.
Abstract:
The therapeutic index of current anti-cancer chemotherapeutics can be improved by two major mechanisms: 1) developing drugs which are specifically toxic to the cancer cells and 2) developing methods to deliver drugs to the tumor site. In an attempt to combine these approaches, we developed a thermally responsive polypeptide inhibitor of c-Myc. This polypeptide is based on the thermally responsive Elastin-like polypeptide (ELP). When injected systemically, ELP-fused drugs will aggregate and accumulate at the tumor site where local hyperthermia is applied. ELP was fused to a peptide which blocks c-Myc/Max dimerization (H1), thereby inhibiting transcription activation by c-Myc (ELP-H1). In this study, the cellular uptake, intracellular distribution, and potency of the Pen, Tat and Bac cell penetrating peptides fused to ELP-H1 were evaluated. While Pen-ELP-H1 and Tat-ELP-H1 were localized in the cytoplasm, Bac-ELP-H1 localized to the nucleus in a subset of the cells and was the most potent inhibitor of MCF-7 cell proliferation. This data demonstrates that ELP can be targeted to the desired cellular compartment simply by choice of the CPP used, resulting in a more potent nuclear targeted c-Myc inhibitory polypeptide which may be beneficial in cancer therapy.
Insights
This study developed a novel polypeptide inhibitor targeting c-Myc, a key cancer protein. By fusing it with cell-penetrating peptides, researchers achieved targeted delivery and enhanced anti-cancer potency, showing promise for improved cancer therapy.
Area of Science:
- Biotechnology
- Molecular Biology
- Cancer Therapeutics
Background:
- Current anti-cancer drugs have limited therapeutic indices.
- Drug delivery and cancer cell specificity are key areas for improvement.
- c-Myc is a crucial transcription factor in cancer development.
Purpose of the Study:
- To develop a thermally responsive polypeptide inhibitor of c-Myc.
- To combine targeted drug delivery with specific cancer cell toxicity.
- To evaluate the efficacy of different cell-penetrating peptides (CPPs) fused to the inhibitor.
Main Methods:
- Development of a thermally responsive Elastin-like polypeptide (ELP) fused to a c-Myc/Max dimerization inhibitor (H1), creating ELP-H1.
- Fusion of ELP-H1 with three different CPPs: Pen, Tat, and Bac.
- Evaluation of cellular uptake, intracellular distribution, and anti-proliferative potency of the resulting constructs in MCF-7 cells.
Main Results:
- Pen-ELP-H1 and Tat-ELP-H1 localized to the cytoplasm.
- Bac-ELP-H1 demonstrated nuclear localization in a subset of cells.
- Bac-ELP-H1 exhibited the most potent inhibition of MCF-7 cell proliferation.
Conclusions:
- ELP-based drug targeting can be modulated by the choice of CPP.
- Nuclear-targeted ELP-H1 via Bac CPP shows enhanced potency as a c-Myc inhibitor.
- This approach offers a promising strategy for developing more effective cancer therapies.
Related Concept Videos
02:57Targeted Cancer Therapies
There are several types of targeted therapies against specific...
01:06Induced Pluripotent Stem Cells
Somatic cells are...
01:19Translocation of Proteins into the Mitochondria
Sorting of outer membrane proteins:
Mitochondrial outer membrane proteins are of two types: the transmembrane, beta-barrel porins, and the membrane-anchored, alpha-helical proteins. Beta-barrel porin precursors are translocated by the TOM complex and inserted into the outer mitochondrial membrane by the SAM complex. In contrast,...