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Published on: June 6, 2022
Optimizing Phosphopeptide Structures That Target 14-3-3ε in Cutaneous Squamous Cell Carcinoma
Seraphine Kamayirese1, Sibaprasad Maity1, Lynne M Dieckman2
1Department of Biomedical Sciences, Creighton University, Omaha, Nebraska 68178, Unites States.
Abstract:
14-3-3ε is involved in various types of malignancies by increasing cell proliferation, promoting cell invasion or inhibiting apoptosis. In cutaneous squamous cell carcinoma (cSCC), 14-3-3ε is over expressed and mislocalized from the nucleus to the cytoplasm where it interacts with the cell division cycle 25 A (CDC25A) and suppresses apoptosis. Hence inhibition of the 14-3-3ε - CDC25A interaction is an attractive target for promoting apoptosis in cSCC. In this work, we optimized the structure of our previously designed inhibitor of 14-3-3ε - CDC25A interaction, pT, a phosphopeptide fragment corresponding to one of the two binding regions of CDC25A to 14-3-3ε. Starting from pT, we developed peptide analogs that bind 14-3-3ε with nanomolar affinities. Peptide analogs were designed by shortening the pT peptide, and introducing modifications at position 510 of the pT(502-510) analog. Both molecular dynamics (MD) simulations and biophysical methods were used to determine peptides binding to 14-3-3ε. Shortening the pT peptide from 14 to 9 amino acid residues resulted in a peptide (pT(502-510)) that binds 14-3-3ε with a KD value of 45.2 nM. Gly to Phe substitution in position 510 of pT(502-510) led to further improvement in affinity (KD: 22.0 nM) of the peptide for 14-3-3ε. Our results suggest that the designed peptide analogs are potential candidates for inhibiting 14-3-3ε -CDC25A interactions in cSCC cells; thus, inducing their apoptosis.
Insights
Researchers developed new peptide analogs that inhibit the 14-3-3ε - CDC25A interaction, a key factor in cutaneous squamous cell carcinoma (cSCC) progression. These optimized peptides show high affinity, offering a potential new therapeutic strategy to induce apoptosis in cSCC cells.
Area of Science:
- Oncology
- Molecular Biology
- Biochemistry
Background:
- 14-3-3ε protein is implicated in various cancers, including cutaneous squamous cell carcinoma (cSCC), by promoting cell survival and invasion.
- In cSCC, 14-3-3ε overexpression and cytoplasmic mislocalization lead to the suppression of apoptosis through interaction with CDC25A.
- Inhibiting the 14-3-3ε - CDC25A interaction presents a promising therapeutic target for inducing apoptosis in cSCC.
Approach:
- The study optimized a previously designed phosphopeptide inhibitor (pT) targeting the 14-3-3ε - CDC25A interaction.
- Peptide analogs were designed by truncating the pT sequence and introducing specific amino acid substitutions.
- Molecular dynamics simulations and biophysical methods were employed to assess the binding affinities of the designed peptides to 14-3-3ε.
Key Points:
- A shortened peptide analog, pT(502-510), demonstrated significant binding affinity to 14-3-3ε with a KD of 45.2 nM.
- A further modification, substituting Glycine with Phenylalanine at position 510, enhanced the binding affinity to 22.0 nM.
- These optimized peptide analogs effectively inhibit the 14-3-3ε - CDC25A interaction.
Conclusions:
- The developed peptide analogs exhibit high affinity for 14-3-3ε, indicating their potential as inhibitors.
- These findings suggest that the designed peptides could serve as novel therapeutic agents for cSCC by inducing apoptosis.
- Further investigation into these peptide analogs may lead to new treatment strategies for cutaneous squamous cell carcinoma.
