Lactoferrin-Decorated PLGA Nanoparticles for Targeted Tamoxifen Repurposing in Glioblastoma Cells

Glioblastoma (GB) classical treatment with the alkylating drug temozolomide (TMZ) is not effective mainly due to chemoresistance mechanisms, particularly those mediated by O6-methylguanine-DNA methyltransferase (MGMT). In this context, polyethylene glycol (PEG)-coated poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) were developed to deliver tamoxifen (TAX), a clinically approved non-alkylating drug with reported anti-GB activity. The NP formulation was optimized using a factorial design and subsequently functionalized with lactoferrin (Lf) to enhance GB targeting. The Lf-conjugated optimized formulation exhibited a mean diameter of 193 ± 6 nm, a polydispersity index (PDI) of 0.11 ± 0.04, a zeta potential of -18.2 ± 6.8 mV, and an encapsulation efficiency (EE) of 68.6 ± 1.8%. The NPs exhibited a sustained release profile for up to 23 days, and remained stable under physiological conditions. Cell uptake studies, conducted in human GB cells (U87, U251, and T98G) and healthy astrocytes, demonstrated enhanced internalization of Lf-NPs in GB cells compared with non-conjugated NPs, suggesting uptake through Lf-binding site-mediated endocytosis. Cytotoxicity assays further indicated that Lf-conjugation improved the antiproliferative efficacy of TAX-loaded NPs relative to non-functionalized formulations, particularly in GB cells. Moreover, combination studies with TMZ showed that the developed NPs were able to sensitize GB cells to treatment with this alkylating agent. In sum, this work supports the potential of the developed Lf-decorated TAX-loaded PLGA NPs as a nanoplatform for targeted delivery against GB.