Polymer-peptide conjugates for angiogenesis targeted tumor radiotherapy

Area of Science:

• Oncology
• Radiotherapy
• Bioconjugation

Background:

• Conventional cancer therapies often fail, necessitating novel radiotherapy delivery methods.
• Tumor cells depend on angiogenesis, making tumor neovasculature a target for treatment.
• Molecularly targeted radiation aims to damage both tumor endothelial cells and neoplastic cells.

Purpose of the Study:

• To assess the effectiveness of beta-emitter radiotherapy delivered by polymer-peptide conjugates targeting tumor neovasculature.
• To evaluate a novel N-(2-Hydroxypropyl) methacrylamide (HPMA) copolymer-RGD4C conjugate for cancer treatment.

Main Methods:

• HPMA copolymer was derivatized for (99m)Tc and (90)Y chelation and conjugated to an alpha(V)beta(3) integrin-targeting peptide (RGD4C).
• The conjugate's side-chain contents, in vitro endothelial cell adhesion, biodistribution, and antitumor effectiveness were evaluated.
• Studies were conducted in a SCID mouse xenograft model of human prostate carcinoma.

Main Results:

• The HPMA copolymer-RGD4C conjugate demonstrated significant tumor accumulation over 72 hours.
• Activity in normal tissues decreased significantly, indicating targeted delivery.
• Tumor volume decreased by up to 63% in (90)Y treatment groups, with increased apoptosis and no acute organ toxicity.

Conclusions:

• The copolymer-peptide conjugate successfully targets tumor angiogenic vessels.
• Sufficient radiotherapy was delivered to arrest tumor growth.
• This targeted approach offers a promising strategy for cancer treatment.