Transport-driven engineering of liposomes for delivery of α-particle radiotherapy to solid tumors: effect on inhibition of tumor progression and onset delay of spontaneous metastases.

Abstract

PURPOSE:

Highly cytotoxic α-particle radiotherapy delivered by tumor-selective nanocarriers is evaluated on metastatic Triple Negative Breast Cancer (TNBC). On vascularized tumors, the limited penetration of nanocarriers (<50-80 μm) combined with the short range of α-particles (40-100 μm) may, however, result in only partial tumor irradiation, compromising efficacy. Utilizing the α-particle emitter Actinium-225 (225Ac), we studied how the therapeutic potential of a general delivery strategy using nanometer-sized engineered liposomes was affected by two key transport-driven properties: (1) the release from liposomes, when in the tumor interstitium, of the highly diffusing 225Ac-DOTA that improves the uniformity of tumor irradiation by α-particles and (2) the adhesion of liposomes on the tumors' ECM that increases liposomes' time-integrated concentrations within tumors and, therefore, the tumor-delivered radioactivities.

METHODS:

On an orthotopic MDA-MB-231 TNBC murine model forming spontaneous metastases, we evaluated the maximum tolerated dose (MTD), biodistributions, and control of tumor growth and/or spreading after administration of 225Ac-DOTA-encapsulating liposomes, with different combinations of the two transport-driven properties.

RESULTS:

At 83% of MTD, 225Ac-DOTA-encapsulating liposomes with both properties (1) eliminated formation of spontaneous metastases and (2) best inhibited the progression of orthotopic xenografts, compared to liposomes lacking one or both properties. These findings were primarily affected by the extent of uniformity of the intratumoral microdistributions of 225Ac followed by the overall tumor uptake of radioactivity. At the MTD, long-term toxicities were not detected 9.5 months post administration.

CONCLUSION:

Our findings demonstrate the potential of a general, transport-driven strategy enabling more uniform and prolonged solid tumor irradiation by α-particles without cell-specific targeting.

• Authors: Aprameya Prasad, Rajiv Nair, Omkar Bhatavdekar, Alaina Howe, Dominick Salerno, Michelle Sempkowski, Anders Josefsson, Jesus Pacheco-Torres, Zaver M Bhujwalla, Kathleen L Gabrielson, George Sgouros, Stavroula Sofou
• Journal: European journal of nuclear medicine and molecular imaging (Eur J Nucl Med Mol Imaging) Vol. 48 Issue 13 Pg. 4246-4258 (12 2021) ISSN: 1619-7089 [Electronic] Germany
• PMID: 34117896 (Publication Type: Journal Article)
• Copyright: © 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.

Chemical References

• Antineoplastic Agents
• Liposomes

Topics

• Alpha Particles (therapeutic use)
• Animals
• Antineoplastic Agents (therapeutic use)
• Cell Line, Tumor
• Humans
• Liposomes
• Mice
• Triple Negative Breast Neoplasms (drug therapy, radiotherapy)