Targeted and synergic glioblastoma treatment: multifunctional nanoparticles delivering verteporfin as adjuvant therapy for temozolomide chemotherapy

摘要： Despite advances in cancer therapies, glioblastoma multiforme treatment remains inefficient due to the brain-blood barrier (BBB) inhibitory activity and to the low Temozolomide (TMZ) chemotherapeutic selectivity. To improve therapeutic outcomes, in this work we propose two strategies: (i) photodynamic therapy (PDT) as adjuvant treatment and (ii) engineering of multifunctional theranostic/targeted nanoparticles (m-NPs) that integrate biotin as a targeting moiety with rhodamine-B as a theranostic agent in Pluronic P85/F127 copolymers. These smart m-NPs can surmount the BBB and co-encapsulate multiple cargoes under optimized conditions. Overall, the present study conducts a rational m-NP design, characterization, and optimizes the formulation conditions. Confocal microscopy studies on T98-G, U87-MG, and U343 glioblastoma cells and on NIH-3T3 normal fibroblast cells show that the m-NPs and the encapsulated drugs are selectively taken up by tumor cells presenting a broad intracellular distribution. The formulations display no toxicity in the absence of light and are not toxic to healthy cells, but they exert a robust synergic action in cancer cells in the case of concomitant PDT/TMZ treatment, especially at low TMZ concentrations and higher light doses, as demonstrated by nonlinear dose–effect curves based on Chou-Talalay method. The results evidenced different mechanisms of action related to the disjoint cell cycle phases at the optimal PDT/TMZ ratio. This effect favors synergism between the PDT and the chemotherapy with TMZ, enhances the antiproliferative effect, and overcomes cross-resistance mechanisms. These results point out that m-NP-based PDT adjuvant therapy is a promising strategy to improve TMZ-based glioblastoma multiforme treatments.