Targeting c-Myc with a novel Peptide Nuclear Delivery Device

Area of Science:

• Molecular Biology
• Cell Biology
• Drug Delivery

Background:

• Biologics like peptides and antibodies are effective therapeutics, but intracellular delivery, especially to the nucleus, is challenging.
• Efficient methods for inhibiting intra-nuclear targets are currently lacking.
• Pseudomonas Exotoxin A (PE) utilizes an endosome-to-nucleus pathway for nucleoplasmic entry.

Purpose of the Study:

• To develop a novel system for efficient nuclear delivery of polypeptidic cargos.
• To create a Peptide Nuclear Delivery Device (PNDD) capable of transporting large molecules to the nucleoplasm.
• To evaluate the therapeutic potential of a PNDD-based c-Myc inhibitor (PNDD1) against cancer, particularly lymphoma.

Main Methods:

• Coupling a non-toxic truncated form of PE to peptides to create the PNDD.
• Utilizing the endosome-to-nucleus trafficking pathway for nuclear import.
• Fusing the PNDD with the c-myc inhibitor peptide H1 to create PNDD1.
• Assessing PNDD1's efficacy in inhibiting c-Myc dependent transcription and its effects on cancer cell proliferation and survival.

Main Results:

• The PNDD successfully delivered polypeptidic cargos, including Glutathione-S-transferase (GST), to the nucleus.
• PNDD1 demonstrated potent inhibition of c-Myc dependent transcription at nanomolar concentrations, significantly more effective than H1 fused to cell-penetrating peptides.
• PNDD1 induced cell death in various tumor cell lines, including patient-derived Diffuse Large B-Cell Lymphomas, while sparing normal B-cells.

Conclusions:

• The PNDD is a highly effective tool for delivering active cargo into the nucleus.
• PNDD1 shows significant promise as a novel therapeutic agent for lymphoma and potentially other cancers by targeting nuclear pathways.