Characterization of a Novel Cytotoxic Cell-penetrating Peptide Derived From p14ARF Protein
Henrik J Johansson1, Samir El-Andaloussi1, Tina Holm1
1Department of Neurochemistry, Stockholm University, Stockholm, Sweden.
Abstract:
The tumor suppressor p14ARF is widely deregulated in many types of cancers and is believed to function as a failsafe mechanism, inhibiting proliferation and inducing apoptosis as cellular response to a high oncogene load. We have found that a 22-amino-acid-long peptide derived from the N-terminal part of p14ARF, denoted ARF(1-22), which has previously been shown to mimic the function of p14ARF, has cell-penetrating properties. This peptide is internalized to the same extent as the cell-penetrating peptide (CPP) TP10 and dose-dependently decreases proliferation in MCF-7 and MDA MB 231 cells. Uptake of the ARF(1-22) peptide is associated with low membrane disturbance, measured by deoxyglucose and lactate dehydrogenase (LDH) leakage, as compared to its scrambled peptide. Also, flow cytometric analysis of annexin V/propidium iodide (PI) binding and Hoechst staining of nuclei suggest that ARF(1-22) induces apoptosis, whereas scrambled or inverted peptide sequences have no effect. The ARF(1-22) peptide mainly translocates cells through endocytosis, and is found intact inside cells for at least 3 hours. To our knowledge, this is the first time a CPP having pro-apoptopic activity has been designed from a protein.
Insights
Researchers developed a novel cell-penetrating peptide (CPP) from the tumor suppressor p14ARF. This peptide, ARF(1-22), effectively enters cells and induces apoptosis, offering a new strategy for cancer therapy.
Area of Science:
- Molecular Biology
- Cancer Research
- Biochemistry
Background:
- The tumor suppressor p14ARF is frequently deregulated in cancers, acting as a failsafe against oncogene-induced proliferation.
- p14ARF's function involves inhibiting cell proliferation and inducing apoptosis.
- Developing therapeutic agents that mimic p14ARF's function is a key area in cancer research.
Purpose of the Study:
- To investigate the cell-penetrating and pro-apoptotic properties of a peptide derived from p14ARF.
- To determine if the ARF(1-22) peptide can be internalized by cells and affect their proliferation.
- To explore the mechanism of uptake and cellular effects of the ARF(1-22) peptide.
Main Methods:
- Synthesis and characterization of the ARF(1-22) peptide.
- Cellular uptake studies using flow cytometry and comparison with a known cell-penetrating peptide (TP10).
- Assays for cell proliferation, membrane integrity (deoxyglucose and LDH leakage), and apoptosis (annexin V/PI staining, Hoechst staining).
Main Results:
- The ARF(1-22) peptide demonstrated significant cell penetration, comparable to TP10.
- ARF(1-22) dose-dependently reduced proliferation in MCF-7 and MDA MB 231 cancer cell lines.
- Apoptosis was induced by ARF(1-22), with minimal membrane disturbance, and uptake occurred primarily via endocytosis.
- The peptide remained intact within cells for at least 3 hours post-treatment.
Conclusions:
- The ARF(1-22) peptide is a novel cell-penetrating peptide with intrinsic pro-apoptotic activity derived from p14ARF.
- This peptide represents a new class of therapeutic agents designed from a tumor suppressor protein.
- ARF(1-22) shows potential for cancer therapy due to its ability to induce apoptosis and penetrate cells effectively.
