Anti-Cancer Peptide PNC-27 Kills Cancer Cells by Unique Interactions with Plasma Membrane-Bound hdm-2 and with Mitochondrial Membranes Causing Mitochondrial Disruption.
Krzesaj. Patryk P; Adler. Victor V; Feinman. Richard D RD; Miller. Anna A; Silberstein. Miriam M; Yazdi. Ehsan E; Pincus. Matthew R MR
Key Findings
- PNC‑27 binds to the p53‑binding region of membrane‑bound HDM‑2 and triggers pore formation that kills cancer cells
- An antibody that blocks the HDM‑2 p53‑binding site stops PNC‑27‑induced cell death, confirming the target
- PNC‑27 enters cancer cells, attaches to mitochondrial membranes, and disrupts them, as shown by loss of Mitotracker staining and gold‑label electron microscopy
Practical Outcomes
- The findings are interesting for understanding how PNC‑27 works, but they don’t translate into a usable protocol for self‑experimenters yet. No dosage, safety, or human data are available, so the peptide remains a laboratory tool rather than a ready‑to‑use anti‑cancer supplement.
Summary
The peptide PNC-27 can stick to a protein called HDM‑2 on the surface of cancer cells, make holes in the cell membrane, and also get inside the cell to damage the mitochondria, which leads to the cancer cells dying. This was shown in lab experiments with pancreatic cancer cells, but it hasn’t been tested in people yet.
Abstract
We have previously shown that the anti-cancer peptide PNC-27 kills cancer cells by co-localizing with membrane-expressed HDM-2, resulting in transmembrane pore formation causing extrusion of intracellular contents. We have also observed cancer cell mitochondrial disruption in PNC-27-treated cancer cells. Our objectives are to determine: 1. if PNC-27 binds to the p53 binding site of HDM-2 (residues 1-109) in the cancer cell membrane and 2. if this peptide causes selective disruption of cancer cell mitochondria. For aim 1, we incubated MIA-PaCa-2 human pancreatic carcinoma cells with PNC-27 in the presence of a monoclonal antibody against the amino terminal p53 binding site of HDM-2 to determine if it, but not negative control immune serum, blocks PNC-27-induced tumor cell necrosis. For the second aim, we incubated these cells with PNC-27 in the presence of two specific dyes that highlight normal organelle function: mitotracker for mitochondria and lysotracker for lysosomes. We also performed immuno-electron microscopy (IEM) with gold-labeled anti-PNC-27 antibody on the mitochondria of these cells treated with PNC-27. Monoclonal antibody to the p53 binding site of HDM-2 blocks PNC-27-induced cancer cell necrosis, whereas negative control immune serum does not. The mitochondria of PNC-27-treated cancer cells fail to retain mitotracker dye while their lysosomes retain lysotracker dye. IEM of the mitochondria cancer cells reveals gold particles present on the mitochondrial membranes. PNC-27 binds to the p53 binding site of HDM-2 (residues 1-109) inducing transmembrane pore formation and cancer cell necrosis. Furthermore, this peptide enters cancer cells and binds to the membranes of mitochondria, resulting in their disruption.
Study Information
pubmed
2024