PNC-27

At a Glance

Classification: Synthetic 32-residue chimeric peptide (p53 residues 12–26 fused to a penetratin cell-penetrating sequence); experimental membrane-active anticancer peptide

PNC-27 is an experimental anticancer peptide built from two parts: • residues 12–26 of the tumor-suppressor protein p53 (PPLSQETFSDLWKLL), the stretch that normally binds MDM-2 (called HDM-2 in humans) • a penetratin "leader" sequence (KKWKMRRNQFWVKVQRG), a positively charged cell-penetrating segment originally taken from a fruit-fly protein. It was developed by Matthew Pincus, Josef Michl and colleagues at SUNY Downstate and affiliated Brooklyn institutions. The headline claim in the lab literature is selectivity. In cell experiments, PNC-27 killed many types of cancer cells while leaving normal cells largely unharmed. It also worked in cancer cells whether their p53 was normal, mutated or missing. The proposed explanation is unusual. Many cancer cells display HDM-2 on their outer membrane. PNC-27 is thought to bind that membrane HDM-2 and punch pores in the cell membrane, causing rapid necrotic cell death rather than standard apoptosis. Important reality check: PNC-27 has not been tested in any published human clinical trial. Its evidence is cell-culture work, patient-derived cells in a dish, and a small number of mouse experiments, almost all from one research network.

What Is PNC-27?

PNC-27 is a synthetic chimeric peptide: p53 residues 12–26 (MDM-2/HDM-2-binding region) + penetratin (cell-penetrating, helix-stabilizing sequence) = PNC-27. A related peptide, PNC-28, uses a shorter p53 fragment (residues 17–26) with the same penetratin sequence. Results for PNC-28 are sometimes discussed together with PNC-27 but belong to a different molecule. Despite being built from a p53 segment, PNC-27 does not act like a p53-restoring drug. Its proposed killing mechanism is membrane damage, not reactivation of p53 signaling.

What Are Researchers Studying?

How Does It Work?

Proposed mechanism (from laboratory studies): PNC-27 ↓ adopts a helical shape that matches how p53 binds HDM-2 ↓ binds HDM-2 sitting on the outer membrane of cancer cells ↓ forms transmembrane pores ↓ membrane rupture → leakage of cell contents (LDH release) → necrosis within hours. Key experimental support: when researchers forced normally resistant, non-cancerous cells to display HDM-2 on their surface, those cells became susceptible to PNC-27. Later work also described PNC-27 interacting with mitochondrial membranes. Whether this mechanism works the same way in a living person, with blood proteins, enzymes that break down peptides, and real tumors, is unknown.

What Does the Research Show?

Notable Studies

What We Still Don't Know

• Whether PNC-27 is safe or effective in any human; no clinical trials have been published • Its stability, half-life and distribution in the body • Whether it reaches solid tumors in useful amounts • Toxicity to normal tissues in living organisms, including cells that may express membrane HDM-2 • Immune reactions to a foreign (penetratin-containing) peptide • Independent replication outside the originating research network • How it compares with standard cancer treatments.

Related Compounds

Sources & References

1. Kanovsky M, Raffo A, Drew L, et al. Peptides from the amino terminal mdm-2-binding domain of p53, designed from conformational analysis, are selectively cytotoxic to transformed cells. Proc Natl Acad Sci U S A. 2001;98(22):12438–12443.
2. Sarafraz-Yazdi E, Bowne WB, Adler V, et al. Anticancer peptide PNC-27 adopts an HDM-2-binding conformation and kills cancer cells by binding to HDM-2 in their membranes. Proc Natl Acad Sci U S A. 2010;107(5):1918–1923.
3. Sookraj KA, Bowne WB, Adler V, et al. The anti-cancer peptide, PNC-27, induces tumor cell lysis as the intact peptide. Cancer Chemother Pharmacol. 2010.
4. Sarafraz-Yazdi E, Gorelick C, Wagreich AR, et al. Ex vivo efficacy of anti-cancer drug PNC-27 in the treatment of patient-derived epithelial ovarian cancer. Ann Clin Lab Sci. 2015;45(6):650–658.
5. Alagkiozidis I, Gorelick C, Shah T, et al. Synergy between paclitaxel and anti-cancer peptide PNC-27 in the treatment of ovarian cancer. Ann Clin Lab Sci. 2017;47(3):271–281.
6. Thadi A, Lewis L, Goldstein E, et al. Targeting membrane HDM-2 by PNC-27 induces necrosis in leukemia cells but not in normal hematopoietic cells. Anticancer Res. 2020;40(9):4857–4867.
7. Krzesaj P, Adler V, Feinman RD, et al. Anti-cancer peptide PNC-27 kills cancer cells by unique interactions with plasma membrane-bound hdm-2 and with mitochondrial membranes causing mitochondrial disruption. Ann Clin Lab Sci. 2024.
8. Krzesaj PK, Seydafkan S, Miller AI, et al. HDM-2-targeting peptide PNC-27 kills cervical cancer cells but not normal cervical cells. Ann Clin Lab Sci. 2025.