Boosting the Therapeutic Efficacy of Discoidal Nanoconstructs against Glioblastoma with Rationally Designed PEG-Docetaxel Conjugates

Polyphosphoester-stabilized cubosomes encapsulating a Ru(II) complex for the photodynamic treatment of lung adenocarcinoma

The clinical translation of photosensitizers based on ruthenium(II) polypyridyl complexes (RPCs) in photodynamic therapy of cancer faces several challenges. To address these limitations, we conducted an investigation to assess the potential of a cubosome formulation stabilized in water against coalescence utilizing a polyphosphoester analog of Pluronic F127 as a stabilizer and loaded with newly synthesized RPC-based photosensitizer [Ru(dppn)2(bpy-morph)](PF6)2 (bpy-morph = 2,2'-bipyridine-4,4'-diylbis(morpholinomethanone)), PS-Ru. The photophysical characterization of PS-Ru revealed its robust capacity to induce the formation of singlet oxygen (1O2). Furthermore, the physicochemical analysis of the PS-Ru-loaded cubosomes dispersion demonstrated that the encapsulation of the photosensitizer within the nanoparticles did not disrupt the three-dimensional arrangement of the lipid bilayer. The biological tests showed that PS-Ru-loaded cubosomes exhibited significant phototoxic activity when exposed to the light source, in stark contrast to empty cubosomes and to the same formulation without irradiation. This promising outcome suggests the potential of the formulation in overcoming the drawbacks associated with the clinical use of RPCs in photodynamic therapy for anticancer treatments.

μMESH-Enabled Sustained Delivery of Molecular and Nanoformulated Drugs for Glioblastoma Treatment

Modest tissue penetrance, nonuniform distribution, and suboptimal release of drugs limit the potential of intracranial therapies against glioblastoma. Here, a conformable polymeric implant, μMESH, is realized by intercalating a micronetwork of 3 × 5 μm poly(lactic-co-glycolic acid) (PLGA) edges over arrays of 20 × 20 μm polyvinyl alcohol (PVA) pillars for the sustained delivery of potent chemotherapeutic molecules, docetaxel (DTXL) and paclitaxel (PTXL). Four different μMESH configurations were engineered by encapsulating DTXL or PTXL within the PLGA micronetwork and nanoformulated DTXL (nanoDTXL) or PTXL (nanoPTXL) within the PVA microlayer. All four μMESH configurations provided sustained drug release for at least 150 days. However, while a burst release of up to 80% of nanoPTXL/nanoDTXL was documented within the first 4 days, molecular DTXL and PTXL were released more slowly from μMESH. Upon incubation with U87-MG cell spheroids, DTXL-μMESH was associated with the lowest lethal drug dose, followed by nanoDTXL-μMESH, PTXL-μMESH, and nanoPTXL-μMESH. In orthotopic models of glioblastoma, μMESH was peritumorally deposited at 15 days post-cell inoculation and tumor proliferation was monitored via bioluminescence imaging. The overall animal survival increased from ∼30 days of the untreated controls to 75 days for nanoPTXL-μMESH and 90 days for PTXL-μMESH. For the DTXL groups, the overall survival could not be defined as 80% and 60% of the animals treated with DTXL-μMESH and nanoDTXL-μMESH were still alive at 90 days, respectively. These results suggest that the sustained delivery of potent drugs properly encapsulated in conformable polymeric implants could halt the proliferation of aggressive brain tumors.

Boosting the Potential of Chemotherapy in Advanced Breast Cancer Lung Metastasis via Micro-Combinatorial Hydrogel Particles

Breast cancer cell colonization of the lungs is associated with a dismal prognosis as the distributed nature of the disease and poor permeability of the metastatic foci challenge the therapeutic efficacy of small molecules, antibodies, and nanomedicines. Taking advantage of the unique physiology of the pulmonary circulation, here, micro-combinatorial hydrogel particles (µCGP) are realized via soft lithographic techniques to enhance the specific delivery of a cocktail of cytotoxic nanoparticles to metastatic foci. By cross-linking short poly(ethylene glycol) (PEG) chains with erodible linkers within a shape-defining template, a deformable and biodegradable polymeric skeleton is realized and loaded with a variety of therapeutic and imaging agents, including docetaxel-nanoparticles. In a model of advanced breast cancer lung metastasis, µCGP amplified the colocalization of docetaxel-nanoparticles with pulmonary metastatic foci, prolonged the retention of chemotoxic molecules at the diseased site, suppressed lesion growth, and boosted survival beyond 20 weeks post nodule engraftment. The flexible design and modular architecture of µCGP would allow the efficient deployment of complex combination therapies in other vascular districts too, possibly addressing metastatic diseases of different origins.