018 | BSA nanoparticles containing collagenases and doxorubicin to enhance therapeutic efficacy in 3D models of solid tumor

Gabriele Lo Buglio^1|2, Alessandra Lo Cicero¹, Simona Campora¹, Paolo Cinà³Samuel Lenton², Vito Foderà², Giulio Ghersi^1|3 | ¹Department of Biological, Chemical and Pharmaceutical Sciences and Technologies STEBICEF, University of Palermo, Italy; ²Department of Pharmacy, University of Copenhagen, Denmark; ³Abiel srl, Palermo, Italy.

Solid tumors are characterized by a complex acidic microenvironment dominated by a dense collagen-rich extracellular matrix (ECM), that act as a major physical barrier to drug penetration, thereby limiting therapeutic efficacy. In this context, strategies that combine ECM remodeling with anticancer drugs represent a promising approach for the cancer treatment [1]. This project aimed to develop bovine serum albumin (BSA)–based nanoparticles loaded with the anticancer drug doxorubicin (BSA–DOX NPs) exhibiting pH-responsive behavior, and to evaluate their therapeutic potential in synergy with BSA-based collagenases nanoparticles designed to remodel the ECM and enhance drug uptake in solid tumors. The BSA–DOX nanoparticles displayed spherical morphology and uniform nanoscale dimensions, achieving a drug loading efficiency of approximately 50%. Under acidic conditions, they exhibit pronounced aggregation, suggesting that this behavior could promote selective intratumoral retention, offering a mechanism that may enhance therapeutic outcomes while reducing off-target effects. In primary breast cancer spheroids, pretreatment with free ultrapure recombinant collagenases significantly increased doxorubicin cytotoxicity, particularly when delivered via BSA–DOX nanoparticles, highlighting a synergistic effect obtained by ECM degradation and nanoparticles conjugated with chemotherapies. Since ultrapure recombinant collagenases (COL H and COL G) are characterized by low immunocompatibility due to their bacterial origin, BSA NPs encapsulating COLH and COLG were developed. Thermal crosslinking strategy enabled the production of BSA-COLH and BSA-COLG NPs with nanoscale dimensions, spherical morphology and good dispersion, preserving enzymatic activity, as shown by zymography assay. Overall, these results indicate that the combination of pH-responsive BSA nanoparticles loaded with doxorubicin and thermally crosslinked collagenase-containing BSA nanoparticles could represents a promising strategy for improving drug delivery and specificity in solid tumors by overcoming stromal barriers and enhancing intratumoral drug accumulation.