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Updated: Mar 7, 2026
Polymalic Acid-based Nano Biopolymers for Targeting of Multiple Tumor Markers: An Opportunity for Personalized Medicine?
Published on: June 13, 2014
Tumor-Penetrating Nanosystem Strongly Suppresses Breast Tumor Growth
Shweta Sharma1, Venkata Ramana Kotamraju1,2, Tarmo Mölder3
1Sanford-Burnham-Prebys Medical Discovery Institute, Cancer Research Center , La Jolla, California 92037, United States.
Abstract:
Antiangiogenic and vascular disrupting compounds have shown promise in cancer therapy, but tend to be only partially effective. We previously reported a potent theranostic nanosystem that was highly effective in glioblastoma and breast cancer mouse models, retarding tumor growth and producing some cures [ Agemy , L. et al. Proc. Natl. Acad. Sci. U.S.A. 2011 , 108 , 17450 - 17455 . Agemy , L. et al. Mol. Ther. 2013 , 21 , 2195 - 2204 .]. The nanosystem consists of iron oxide NPs ("nanoworms") coated with a composite peptide with tumor-homing and pro-apoptotic domains. The homing component targets tumor vessels by binding to p32/gC1qR at the surface or tumor endothelial cells. We sought to further improve the efficacy nanosystem by searching for an optimally effective homing peptide that would also incorporate a tumor-penetrating function. To this effect, we tested a panel of candidate p32 binding peptides with a sequence motif that conveys tumor-penetrating activity (CendR motif). We identified a peptide designated as Linear TT1 (Lin TT1) (sequence: AKRGARSTA) as most effective in causing tumor homing and penetration of the nanosystem. This peptide had the lowest affinity for p32 among the peptides tested. The low affinity may have moderated the avidity effect from the multivalent presentation on nanoparticles (NPs), such that the NPs avoid getting trapped by the so-called "binding-site barrier", which can hinder tissue penetration of compounds with a high affinity for their receptors. Treatment of breast cancer mice with the LinTT1 nanosystem showed greatly improved efficacy compared to the original system. These results identify a promising treatment modality and underscore the value of tumor penetration effect in improving the efficacy tumor treatment.
Insights
Researchers developed an improved cancer therapy nanosystem using a novel peptide for enhanced tumor homing and penetration. This new Linear TT1 (Lin TT1) nanosystem significantly boosted treatment efficacy in preclinical breast cancer models.
Area of Science:
- Biomedical Engineering
- Nanotechnology
- Cancer Therapy
Background:
- Antiangiogenic and vascular disrupting agents show promise but have limited efficacy in cancer treatment.
- Previous theranostic nanosystems (iron oxide NPs with composite peptides) demonstrated effectiveness in glioblastoma and breast cancer models.
- The prior nanosystem's homing peptide targeted tumor vessels via p32/gC1qR, but further optimization was sought.
Purpose of the Study:
- To enhance the efficacy of a theranostic nanosystem by identifying an optimal homing peptide with tumor-penetrating capabilities.
- To investigate the role of peptide-receptor affinity and the binding-site barrier in nanoparticle tumor penetration.
- To evaluate the therapeutic potential of a novel nanosystem incorporating a tumor-penetrating peptide.
Main Methods:
- A panel of p32-binding peptides incorporating the CendR tumor-penetrating motif was synthesized and tested.
- The peptide Linear TT1 (Lin TT1) was identified as the most effective for tumor homing and penetration.
- The efficacy of the Lin TT1-modified nanosystem was assessed in preclinical breast cancer models.
Main Results:
- Linear TT1 (Lin TT1) demonstrated superior tumor homing and penetration compared to other tested peptides.
- Lin TT1 exhibited a lower affinity for p32, potentially mitigating the binding-site barrier effect.
- The Lin TT1 nanosystem showed significantly improved therapeutic efficacy in breast cancer mouse models compared to the original system.
Conclusions:
- The development of the Lin TT1 nanosystem represents a promising advancement in cancer therapy.
- Tumor penetration is a critical factor for enhancing the efficacy of nanoparticle-based cancer treatments.
- Optimizing peptide-receptor interactions and leveraging tumor-penetrating motifs can overcome delivery barriers and improve therapeutic outcomes.
