🔬 Research Only • Not FDA Approved

PNC-27

32-amino acid chimeric anticancer peptide that targets membrane-localized HDM2/MDM2 on tumor cells, forming pores and triggering necrotic death in preclinical models.

Length 32 aa MW ~4031 Da Target HDM2/MDM2 ⚠️

FDA Warning (2017)

The FDA has warned cancer patients not to use PNC-27 products for treatment due to contamination findings and lack of established safety/efficacy. PNC-27 is for laboratory research only — no human use is endorsed or implied.

⚡ Executive Summary

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.

Jump to section

01 Overview 02 Properties 03 Mechanism 04 Evidence 05 Limitations 06 Protocol 📋

Overview

🧬 What is PNC-27?

PNC-27 is a 32-residue chimeric peptide that fuses the p53 transactivation segment (residues 12–26) to a cell-penetrating leader.

It binds HDM2/MDM2 in tumor-cell membranes and forms transmembrane pores that precipitate necrotic cell death.

🎯 Key Features

• 🔗 Membrane HDM2 binding — targets surface protein
• 🕳️ Pore formation — transmembrane complexes
• 💀 Necrotic death — rapid LDH release

🔬

Entity Properties

Aliases	PNC-27, PNC27, p53(12–26)–penetratin/MRP chimera
Sequence	PPLSQETFSDLWKLLKKWKMRRNQFWVKVQRG
Length	32 amino acids
Molecular Weight	~4031 Da
CAS	Not assigned (research peptide)
Target	Membrane-localized HDM2/MDM2
Diluent(s)	Sterile water, PBS; validate for your assay
Concentration	~10–100 µg/mL (≈2.5–25 µM) in vitro
Storage	Lyophilized ≤ −20°C, desiccated, light-protected

⚙️

Mechanism of Action

🧠 How does PNC-27 work?

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 — it works on p53-null cells like K562 leukemia.

🔗 Step 1: Binding

p53(12–26) segment binds to HDM2 at residues 1–109 on tumor cell membrane surface

🕳️ Step 2: Pore Formation

PNC-27–HDM2 complexes assemble into transmembrane pore structures (visualized by immuno-EM)

💀 Step 3: Necrosis

Membrane integrity compromised → rapid LDH release → necrotic cell death within hours

💡

Why membrane HDM2? HDM2/MDM2 is usually intracellular, but several groups report aberrant HDM2 at tumor plasma membranes, enabling extracellular targeting independent of p53 status.

📊

Experimental Evidence

🔬 In Vitro / Preclinical Findings

🎯

Broad Cytotoxicity

Kills diverse tumor lines (pancreatic, melanoma, breast, ovarian, leukemia) while sparing normal cells

🧬

p53-Independent

Efficiently lyses K562 leukemia cells (p53-null), confirming membrane-targeted mechanism

🩸

Leukemia Models

U937, OCI-AML3, HL-60: LDH release within hours, reduced colony formation

🔬

Ovarian Cancer (ex vivo)

Primary cultures including chemoresistant subsets showed selective cytotoxicity

🔑 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.

⚠️

Limitations & Safety

🚨 Critical Limitations

• ✗ No FDA approval — explicitly warned patients not to use (2017)
• ✗ No human efficacy trials — no randomized or prospective data published
• ✗ Safety signals — case report of massive GI hemorrhage after experimental use abroad
• ✗ Limited reproducibility — substantial literature from limited set of laboratories
• ○ Generalizability — tumors without membrane HDM2 may be insensitive

🚫

Any use must remain laboratory-only. Broader, independent replications with standardized protocols are essential before any translational consideration.

🧪

Research Protocol Guidelines

📘

Educational only. Designing a rigorous PNC-27 in-vitro study to test HDM2-dependent pore formation.

1

Select Models

Choose tumor lines with membrane HDM2 + matched normal cells + p53-null line (e.g., K562)

2

Verify Target

Confirm surface HDM2 by flow cytometry/immunostaining before dosing

3

Prepare Stocks

Reconstitute in sterile water/PBS; single-use aliquots; avoid freeze-thaw

4

Dose-Response

~10–100 µg/mL (≈2.5–25 µM); time points 0.5–24h for LDH release

5

Controls

Vehicle, PNC-29 (negative), anti-HDM2 blocking, nutlin (intracellular comparator)

6

Measure Outcomes

LDH release, viability assays, co-localization imaging, immuno-EM for pores

🎯 Information-Gain Framework

• 1️⃣ HDM2-Gate: Only proceed when surface HDM2 is verified
• 2️⃣ Pore-Proof: Pair LDH↑ with co-localization/pore imaging
• 3️⃣ Selectivity-Score: Quantify tumor vs. normal kill and relate to HDM2 levels

⚖️

Comparison

Where does PNC-27 sit among membrane-active/peptide oncology approaches?

PNC-27

Membrane HDM2 → Pore → Necrosis PRECLINICAL

Targets surface HDM2 on tumor cells; pore-associated necrosis; spares normal cells lacking membrane HDM2.

LTX-315

Cationic membranolytic → ICD PHASE I

Tumor-selective membranolysis with T-cell infiltration; converts “cold” to “hot” tumors.

p28 (azurin)

Intracellular p53 stabilization PHASE I

Non-lytic mechanism; enters cancer cells and stabilizes/activates p53 → apoptosis.

ℹ️

PNC-27 remains preclinical, whereas LTX-315 and p28 have Phase I human data (safety, pharmacodynamics), though neither is broadly approved for cancer treatment.

❓

FAQ

What is PNC-27? A 32-amino-acid peptide that fuses p53(12–26) to a cell-penetrating leader, binding membrane HDM2/MDM2 to form pores and cause necrotic death in tumor cells. Research use only. How does PNC-27 kill cancer cells? By co-localizing with membrane HDM2, assembling transmembrane pores, and compromising membrane integrity (LDH release). This is p53-independent. Is PNC-27 FDA-approved? No. In 2017 the FDA warned patients NOT to use PNC-27 products for cancer treatment due to contamination and lack of evidence. Are there human clinical trials? No randomized or prospective human efficacy trials have been published. A case report described massive GI hemorrhage after experimental use abroad. Does PNC-27 require functional p53? No — the mechanism is p53-independent because it acts at the cell membrane via HDM2. P53-null K562 cells are killed by PNC-27. What concentrations are used in vitro? ~10–100 µg/mL (≈2.5–25 µM) with minutes-to-hours exposures; optimize empirically for your model and assay endpoints. ✅

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.