New Lipopeptide Platform for Delivering Peptides and Proteins Into Cells

Novel peptide gemini surfactants with lysine-based sequences outperform the established R8 cell-penetrating peptide in delivering therapeutic peptides to the cytoplasm.

Sumito, Natsumi et al.·Bioconjugate chemistry·2020·Preliminary Evidencein vitro
RPEP-05151In vitroPreliminary Evidence2020RETHINKTHC RESEARCH DATABASErethinkthc.com/research

Quick Facts

Study Type
in vitro
Evidence
Preliminary Evidence
Sample
N=not applicable
Participants
NIH3T3 cells (in vitro screening)

What This Study Found

CP-PGs with tri-lysine sequences (DKCK12-K3 and DKCK12-K5) showed lower cytotoxicity and superior peptide delivery compared to the well-established R8 cell-penetrating peptide.

Key Numbers

EC50: 5.8-6.2 µM (best) vs 6.8 µM (R8); IC50: 198-241 µM (K3) vs 88 µM (R3); two C12 chains

How They Did This

Peptide synthesis, cytotoxicity assays on NIH3T3 cells, proapoptotic peptide (PAD) delivery assays measuring cell death as a functional readout of cytosolic delivery.

Why This Research Matters

Getting therapeutic peptides inside cells remains a major drug delivery challenge. These new carriers achieve better delivery than established CPPs while maintaining low toxicity.

The Bigger Picture

This PG-surfactant molecular framework offers a new platform for designing cell-penetrating carriers, expanding the toolkit for intracellular peptide and protein drug delivery.

What This Study Doesn't Tell Us

In vitro only using a single cell line. Functional readout based on apoptotic activity rather than direct delivery measurement. No in vivo data.

Questions This Raises

  • ?Do CP-PGs maintain their carrier ability in vivo?
  • ?Can this platform deliver larger proteins effectively?
  • ?How does delivery efficiency compare across different cell types?

Trust & Context

Key Stat:
6.2 μM EC50 DKCK12-K3 carrier ability for cytosolic peptide delivery, outperforming the established R8 CPP
Evidence Grade:
In vitro proof-of-concept comparing new carriers to an established standard. Early-stage but with quantitative performance data.
Study Age:
Published in 2020. Cell-penetrating peptide research continues to advance with new delivery platforms.
Original Title:
Development of Cell-Penetration PG-Surfactants and Its Application in External Peptide Delivery to Cytosol.
Published In:
Bioconjugate chemistry, 31(3), 821-833 (2020)
Database ID:
RPEP-05151

Evidence Hierarchy

Meta-Analysis / Systematic Review
Randomized Controlled Trial
Cohort / Case-Control
Cross-Sectional / ObservationalSnapshot without intervening
This study
Case Report / Animal Study
What do these levels mean? →

Frequently Asked Questions

Why is getting peptides into cells so difficult?

Cell membranes act as barriers that prevent most peptides from entering. Peptide drugs often need to reach targets inside cells but can't cross the membrane on their own. Cell-penetrating agents like these CP-PGs help shuttle therapeutic peptides across the membrane.

What makes these new carriers better?

The CP-PG carriers combine two alkyl chains with cationic peptide sequences in a unique architecture. The best variants delivered a therapeutic peptide more efficiently than the well-established R8 peptide while causing less cell damage.

Read More on RethinkPeptides

Cite This Study

RPEP-05151·https://rethinkpeptides.com/research/RPEP-05151

APA

Sumito, Natsumi; Koeda, Shuhei; Umezawa, Naoki; Inoue, Yasumichi; Tsukiji, Shinya; Higuchi, Tsunehiko; Mizuno, Toshihisa. (2020). Development of Cell-Penetration PG-Surfactants and Its Application in External Peptide Delivery to Cytosol.. Bioconjugate chemistry, 31(3), 821-833. https://doi.org/10.1021/acs.bioconjchem.9b00877

MLA

Sumito, Natsumi, et al. "Development of Cell-Penetration PG-Surfactants and Its Application in External Peptide Delivery to Cytosol.." Bioconjugate chemistry, 2020. https://doi.org/10.1021/acs.bioconjchem.9b00877

RethinkPeptides

RethinkPeptides Research Database. "Development of Cell-Penetration PG-Surfactants and Its Appli..." RPEP-05151. Retrieved from https://rethinkpeptides.com/research/sumito-2020-development-of-cellpenetration-pgsurfactants

Access the Original Study

Study data sourced from PubMed, a service of the U.S. National Library of Medicine, National Institutes of Health.

This study breakdown was produced by the RethinkPeptides research team. We analyze and report published research findings without making health recommendations. All interpretations are based solely on the published abstract and study data.