Educational reference only. Nothing on this page constitutes medical advice or encourages personal use of this compound. Always consult a qualified healthcare provider before any decision involving your health.

PNC-28

Animal replicated

Off-labelp53-Derived Peptide Anticancer Peptide Cell-Penetrating Peptide

RouteInjectableGray-market only

Evidence grade: Animal replicated

Effect demonstrated in multiple animal studies; human data sparse or extrapolated. Grades summarize evidence quality, not whether a compound is appropriate, legal, or risk-free.

At a glance

What it is: p53 MDM2-Binding Domain Peptide + Penetratin — Membrane-Active Anti-Cancer Peptide — Tumor-Selective — p53-Derived Peptide, Anticancer Peptide, Cell-Penetrating Peptide.
Why people use it: Used primarily for immune support.
What the evidence supports: PNC-28 is a chimeric peptide containing two distinct domains: p53 AA17-26 (TFSDLWKLL) and penetratin (RQIKIWFQNRRMKWKK). The full peptide sequence and MW require HPLC purity verification (≥98%) and mass spectrometric identity confirmation. Penetratin contains multiple arginine and lysine residues (highly positive charge) that create reconstitution and aggregation challenges. Community suppliers (Xcells) list PNC-28; verify independent third-party testing certificates before use. Storage: lyophilized; refrigerate; reconstitute in sterile water or appropriate peptide solvent. Do not reconstitute in acidic buffers that could affect the basic penetratin domain's solubility. Route: SubQ injection is the primary community route; IV or intratumoral routes were used in some research contexts.

If you only read one thing

PNC-28 inverts the standard Compound Report cancer calculus. Every other chapter warns against using its compound in cancer patients because GH, IGF-1, angiogenesis, or cell proliferation signals could feed tumor growth. PNC-28 was designed to exploit a cancer-specific surface marker (plasma membrane MDM2) to deliver a lethal pore-forming signal selectively to tumor cells. The in vitro human cancer cell data is compelling — necrosis of 20+ cancer cell lines, pore formation confirmed ultrastructurally. The in vivo mouse data shows tumor growth inhibition. What does not exist is a published human Phase 3 trial. The community using PNC-28 for general health without active cancer is using an anti-cancer peptide in a population where its primary mechanism has no pharmacological target (no plasma membrane MDM2 to bind).

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Published literature

0human trials0human studies1animal8in vitro

Evidence reality check

Human evidence

No human studies

0 observational; RCT evidence not present in corpus.

Preclinical base

9 lab signals

1 animal; 8 in-vitro/mechanistic.

Evidence snapshot

PNC-28 is a chimeric peptide containing two distinct domains: p53 AA17-26 (TFSDLWKLL) and penetratin (RQIKIWFQNRRMKWKK). The full peptide sequence and MW require HPLC purity verification (≥98%) and mass spectrometric identity confirmation. Penetratin contains multiple arginine and lysine residues (highly positive charge) that create reconstitution and aggregation challenges. Community suppliers (Xcells) list PNC-28; verify independent third-party testing certificates before use. Storage: lyophilized; refrigerate; reconstitute in sterile water or appropriate peptide solvent. Do not reconstitute in acidic buffers that could affect the basic penetratin domain's solubility. Route: SubQ injection is the primary community route; IV or intratumoral routes were used in some research contexts.

From the chapter quick-reference block.

Categories

Immune & Thymic

Properties

Active malignancy: cautionSingle-lab provenanceNot injectable

Evidence

CAnimal replicated

PNC-27 vs PNC-28

PNC-27 uses p53 AA12-26 (longer sequence: includes amino acids 12-26). PNC-28 uses p53 AA17-26 (shorter: amino acids 17-26 only). Both include the penetratin membrane insertion sequence. Both target MDM2 on cancer cell membranes. Both produce tumor cell necrosis in vitro. PNC-28 has been shown to destroy highly metastatic cancer cells with particular effectiveness. The two compounds share the same mechanism; PNC-27 is slightly longer and has a broader initial literature base; PNC-28 may have enhanced potency for some tumor types due to the shorter, more focused MDM2-binding sequence. No direct clinical head-to-head exists.

The Selectivity Mechanism

MDM2 (murine double minute 2; human homolog: hdm2) is normally a nuclear/cytoplasmic E3 ubiquitin ligase that ubiquitinates p53 for proteasomal degradation. Cancer cells constitutively overexpress MDM2 and, critically, express MDM2 on the plasma membrane. Normal cells do not express MDM2 on their plasma membrane surface. PNC-28 (and PNC-27) exploit this: the p53 domain of the peptide binds MDM2 on the cancer cell surface; the penetratin sequence inserts the peptide into the lipid bilayer; multiple PNC molecules oligomerize around the MDM2 anchor to form transmembrane pores; the pores cause direct cell lysis (necrosis) within minutes to hours.

Evidence Grade

D (in vitro human cancer cell lines): necrosis confirmed in 20+ human epithelial cancer cell lines including pancreatic, colon, lung, breast, ovarian, leukemia; pore formation confirmed ultrastructurally (AACR 2008). C (in vivo mouse): PNC-28 blocks pancreatic cancer cell growth in vivo in mouse xenograft models (Pincus 2006, Int J Cancer). No published human RCT for PNC-28 specifically. Community use: Grade E.

The Community Off-Label Reality

Community users access PNC-28 through Xcells and research chemical vendors for general 'cellular health,' 'p53 pathway support,' or adjunctive cancer support. The 'p53 activation' framing in community discussion is a mischaracterization of the mechanism: PNC-28 does not activate nuclear p53 signaling. It binds MDM2 on cancer cell surfaces and kills those cells by pore formation. In people without cancer (no MDM2-expressing cells in the plasma membrane), PNC-28's primary mechanism has no target. The compound's community use for general health is pharmacologically the most off-context application in this reference.

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