PNC‑27 (also written PNC27 or PNC 27) is a 32–amino acid chimeric peptide that fuses the p53 transactivation segment (residues 12–26) to a cell‑penetrating leader. In tumor models, it binds membrane HDM2/MDM2, assembles transmembrane pores, and causes rapid necrosis while largely sparing normal cells. After this brief standardization, this article uses PNC‑27 consistently. (PMC)
Fast Answer / Executive Summary (40–60 words)
PNC‑27 is a research‑only anticancer peptide that targets membrane‑localized HDM2 (also called MDM2) on some tumor cells, forms pore‑like complexes, and triggers necrotic death in preclinical models. It is not FDA‑approved, lacks published human efficacy trials, and has drawn regulatory warnings about unapproved patient use. Reserve it strictly for laboratory research. (PMC)
Entity Properties (for researchers)
| Property | Details |
|---|---|
| Aliases / Synonyms | PNC‑27; p53(12–26)–penetratin/MRP chimera; HDM2‑targeted lytic peptide |
| Family / Pathway | Membrane‑active oncolytic peptide; interacts with HDM2/MDM2 (p53 negative regulator); induces necrotic death via pore formation |
| Sequence (AA) | PPLSQETFSDLWKLLKKWKMRRNQFWVKVQRG (32 aa) |
| Molecular Weight (Da) | ~4031 (from sequence) |
| CAS | Not assigned (research peptide) |
| Typical Diluent(s) | Aqueous buffers (e.g., sterile water, PBS); validate solubility and compatibility for your assay |
| Example Concentration(s) (educational) | Reported in vitro ranges ~10–100 µg/mL (≈2.5–25 µM) with time‑dependent LDH release/necrosis; optimize empirically per model |
| Storage | Lyophilized at ≤ –20 °C (preferably colder), desiccated, protected from light; after reconstitution, aliquot and refrigerate/freeze to avoid repeated freeze–thaw |
Notes & sources: The sequence/size are reported in peer‑reviewed literature and databases; concentration bands reflect doses used across leukemia and solid‑tumor cell models; storage practices follow peer‑reviewed/consensus guidance for peptides/lyophilized biologics. (PMC)
Core Concepts & Key Entities
What is PNC‑27—and how does it work?
PNC‑27 is a 32‑residue chimeric peptide that binds HDM2/MDM2 in tumor‑cell membranes and forms transmembrane pores that precipitate necrotic cell death. The p53(12–26) segment confers HDM2 binding, while the leader sequence supports membrane engagement. Electron microscopy, co‑localization, and LDH‑release assays demonstrate pore‑associated necrosis in cancer cells but not in matched normal cells under identical conditions. (PMC)
Why target HDM2/MDM2 at the membrane?
HDM2/MDM2 is best known as an intracellular E3 ligase that suppresses p53. Several groups report aberrant HDM2 at the tumor plasma membrane, enabling extracellular targeting. PNC‑27 leverages this to bind membrane HDM2, co‑localize at the surface, and assemble pore‑like structures visualized by immuno‑EM—a mechanism independent of p53 status. (PMC)
What does the experimental evidence show?
- Broad in‑vitro cytotoxicity with selectivity claims: PNC‑27 kills diverse tumor cell lines (e.g., pancreatic, melanoma, breast, ovarian, leukemia) while sparing normal cells in the same assays; pores lined by PNC‑27–HDM2 complexes have been reported by immuno‑SEM and related imaging. (Annals of Clinical Laboratory Science)
- p53‑independent activity: PNC‑27 efficiently lyses K562 leukemia cells, which are p53‑null, supporting membrane‑targeted rather than nuclear p53‑dependent activity. (PubMed)
- Leukemia models: In U937, OCI‑AML3, HL‑60 and other leukemia lines, PNC‑27 co‑localizes with membrane HDM2, triggers LDH release within hours, and reduces colony formation; normal hematopoietic cells are comparatively resistant under matched conditions. (PubMed)
- Patient‑derived ovarian cancer (ex vivo): Primary epithelial ovarian cancer cultures (including chemoresistant subsets) showed selective cytotoxicity to PNC‑27; this has been cited in oncology reviews discussing peptide strategies for ovarian tumors. (PubMed)
- Mechanistic updates (2024): Antibody‑blocking/epitope mapping indicates PNC‑27 binds the p53 site on HDM2 (residues 1–109); mitochondrial disruption appears downstream of membrane pore formation. (PubMed)
Key takeaway: PNC‑27 consistently shows HDM2‑dependent, membrane‑pore formation and necrotic killing of tumor cells in preclinical models—with relative sparing of normal cells—independent of tumor p53 status. (PMC)
What are the limitations and safety signals?
- Regulatory status: No FDA approval or authorization exists for PNC‑27. In 2017, the FDA warned cancer patients not to use PNC‑27 products, citing contamination (e.g., Ralstonia insidiosa) in an inhalation sample and the lack of established safety/efficacy. Any use must remain laboratory‑only. (U.S. Food and Drug Administration)
- Human data: No randomized or prospective human efficacy trials have been published. A 2017 case report described massive gastrointestinal hemorrhage after experimental PNC‑27 administration abroad; causality is uncertain but underscores risk and the need for ethical oversight. (Lippincott Journals)
- Reproducibility/independence: A substantial portion of the literature comes from a limited set of laboratories; broader, independent replications with standardized protocols are essential. (See citations throughout.)
- Generalizability: Activity appears to correlate with membrane HDM2; tumor types without this feature may be insensitive. (PubMed)
Step‑by‑Step / How‑To (Educational): Designing a Rigorous PNC‑27 In‑Vitro Study
Goal: Determine whether membrane HDM2–dependent pore formation explains PNC‑27 response in your model—while quantifying selectivity vs. normal cells.
1) Select biologically justified models
Choose tumor lines with evidence of membrane HDM2 (literature or your own screening). Include matched normal cell counterparts and at least one p53‑null tumor line (e.g., K562) to test p53‑independence directly. (PubMed)
2) Verify target exposure: surface HDM2
Confirm plasma‑membrane HDM2 by flow cytometry/surface immunostaining prior to dosing. In leukemia models and solid tumors, PNC‑27 response tracks with membrane HDM2 presence. (PubMed)
3) Prepare peptide stocks with stability in mind
Reconstitute in compatible aqueous buffer (e.g., sterile water or PBS) appropriate to your assay; prepare single‑use aliquots; store cold and avoid repeated freeze–thaw to preserve integrity—best practices documented in Clinical Chemistry (CPTAC consensus) and lyophilized product stability literature. (PubMed)
4) Design dose–response and time course
Anchor initial ranges to peer‑reviewed reports: ~10–100 µg/mL (≈2.5–25 µM) with sampling at 0.5–24 h to capture LDH release and rapid necrosis. Calibrate around EC50 and time‑to‑lysis for your specific lines. (PubMed)
5) Run the right controls
Include: vehicle, negative‑control peptide (e.g., PNC‑29), and mechanism comparators (e.g., nutlin as an intracellular HDM2 inhibitor) to contrast with membrane‑pore activity. Use isotype or anti‑HDM2 blocking to test target dependence. (MDPI)
6) Measure orthogonal outcomes
Primary: LDH release (necrosis) and viability assays (MTT/CellTiter). Secondary: co‑localization imaging of PNC‑27 + HDM2 at the membrane and, where feasible, immuno‑EM for pore structures. (Annals of Clinical Laboratory Science)
7) Quantify selectivity
Apply the same protocol to normal cells. Report tumor‑to‑normal kill ratios and HDM2 surface levels to contextualize selectivity claims for your system. (PubMed)
8) Explore downstream effects (optional)
Track mitochondrial integrity (e.g., Mitotracker retention) and other organellar changes reported downstream of pore formation in recent mechanistic work. (PubMed)
9) Document and pre‑register internally
Given active debate and translational interest, transparent, reproducible methods (including negative results) add field value.
Information‑gain framework: HDM2‑Gate → Pore‑Proof → Selectivity‑Score
HDM2‑Gate: Only proceed when surface HDM2 is verified.
Pore‑Proof: Pair LDH↑ with co‑localization/pore imaging.
Selectivity‑Score: Quantify tumor vs. normal kill and relate to HDM2 levels. (PubMed)
Comparison / Alternatives (“X vs Y” context)
Where does PNC‑27 sit among membrane‑active/peptide oncology approaches?
| Peptide | Core Mechanism | Primary Target/Context | Selectivity Claim (models) | Clinical Status (Oct 2025) | Notes & sources |
|---|---|---|---|---|---|
| PNC‑27 | Binds membrane HDM2/MDM2 → pore formation → necrosis | Tumor cells with surface HDM2 | Spares normal cells lacking membrane HDM2 | No human efficacy trials; not FDA‑approved | Multiple in‑vitro/ex‑vivo studies; antibody blocking and pore visualization; regulatory warning for patient use (2017). (PMC) |
| LTX‑315 | Cationic membranolytic oncolytic peptide → immunogenic cell death | Negatively charged tumor membranes; TME remodeling | Tumor‑selective membranolysis with T‑cell infiltration | Phase I monotherapy/combination data; ongoing exploration | Converts “cold” to “hot” tumors; clinical signals with checkpoint blockade. (AACR Journals) |
| p28 (azurin‑derived) | Enters cancer cells; stabilizes/activates p53 (non‑HDM2 route) → apoptosis/cell‑cycle effects | Intracellular p53 interface | Cancer‑preferential uptake | Two Phase I trials (adult & pediatric) | Distinct, non‑lytic mechanism; useful comparator for p53‑modulating peptides. (PMC) |
This context emphasizes that PNC‑27 remains preclinical, whereas LTX‑315 and p28 have Phase I human data (safety, pharmacodynamics), though neither is broadly approved for cancer treatment. (AACR Journals)
Templates / Checklist / Example
Research‑Readiness Checklist for PNC‑27 (copy‑ready)
- Define scope: Restrict all work to laboratory research; no human use; document FDA warning and non‑approval status. (U.S. Food and Drug Administration)
- Choose models smartly: Select HDM2‑positive tumor lines plus matched normal cells to test selectivity. (PubMed)
- Verify target exposure: Confirm surface HDM2 by flow cytometry/surface staining before dosing. (PubMed)
- Prepare stocks carefully: Use compatible aqueous buffers; aliquot; store cold; avoid freeze–thaw per CPTAC/lyophilized stability guidance. (PubMed)
- Plan dosing/time: Start around 10–100 µg/mL (≈2.5–25 µM) with 0.5–24 h time points; refine to model‑specific kinetics. (PubMed)
- Include proper controls: PNC‑29 (negative), vehicle, anti‑HDM2 blocking, and an intracellular HDM2 inhibitor (e.g., nutlin) as a mechanistic contrast. (MDPI)
- Capture mechanism: Pair LDH release with HDM2/PNC‑27 co‑localization; add immuno‑EM for pore visualization when feasible. (Annals of Clinical Laboratory Science)
- Quantify selectivity: Report tumor‑to‑normal kill ratios and correlate with HDM2 surface levels. (PubMed)
- Report with transparency: Archive raw data and negative findings; note any off‑target cytotoxicity.
FAQs (NLP‑friendly, answer‑first)
What is PNC‑27?
PNC‑27 is a 32‑amino‑acid peptide that fuses the p53(12–26) segment to a cell‑penetrating leader and binds HDM2/MDM2 at tumor‑cell membranes to form pores, causing necrotic death in models. It is for research use only. (PMC)
How does PNC‑27 kill cancer cells?
PNC‑27 kills cancer cells by co‑localizing with membrane HDM2 and assembling transmembrane pores, which rapidly compromise membrane integrity (LDH release) and can precede mitochondrial disruption; the effect is p53‑independent. (PMC)
Is PNC‑27 FDA‑approved?
No. PNC‑27 is not FDA‑approved for any indication. In 2017 the FDA warned patients not to use PNC‑27 products marketed for cancer treatment due to contamination findings and lack of evidence. Use is restricted to controlled laboratory research. (U.S. Food and Drug Administration)
Are there human clinical trials showing PNC‑27 works?
There are no published randomized or prospective human efficacy trials of PNC‑27. A case report described massive GI hemorrhage after experimental treatment administered outside the U.S., emphasizing risk and the need for rigorous oversight. (Lippincott Journals)
Does PNC‑27 require functional p53 in tumor cells?
No—PNC‑27’s mechanism is p53‑independent because it acts at the cell membrane via HDM2. For example, p53‑null K562 leukemia cells are killed by PNC‑27 in vitro. (PubMed)
What concentrations and exposure times are typical in vitro?
Published studies often test ~10–100 µg/mL (≈2.5–25 µM) with minutes‑to‑hours exposures that produce LDH release and necrosis in responsive tumor lines; always optimize empirically for your model and assay endpoints. (PubMed)
How should researchers store and handle PNC‑27?
Store lyophilized peptide at ≤ –20 °C (preferably colder), protected from light and moisture; after reconstitution, aliquot and avoid repeated freeze–thaw. These practices follow CPTAC consensus and lyophilized drug‑product guidance. (PubMed)
Next Steps
If you’re evaluating membrane‑targeted lytic strategies in vitro, PNC‑27 offers a mechanistically distinct probe: confirm surface HDM2, visualize pore formation, and quantify necrotic kinetics. For an educational protocol overview, see: PNC‑27 30 mg Vial: Dosage Protocol (educational). For research‑grade PNC‑27 (no human use), see PureLabPeptides: PNC‑27 30 mg.
Bottom line: PNC‑27 is a research‑only peptide with a compelling membrane‑HDM2 pore‑formation mechanism and selective tumor cytotoxicity in models—but without human efficacy data and under explicit FDA warnings. Design target‑verified, control‑rich experiments before inferring translational potential. (PMC)