Supramolecular Heterodimer Peptides Assembly for Nanoparticles Functionalization.

Nanoparticle (NP) surface functionalization with proteins, including monoclonal antibodies (mAbs), mAb fragments, and various peptides, has emerged as a promising strategy to enhance tumor targeting specificity and immune cell interaction. However, these methods often rely on complex chemistry and suffer from batch-dependent outcomes, primarily due to limited control over the protein orientation and quantity on NP surfaces. To address these challenges, a novel approach based on the supramolecular assembly of two peptides is presented to create a heterotetramer displaying VHHs on NP surfaces. This approach effectively targets both tumor-associated antigens (TAAs) and immune cell-associated antigens. In vitro experiments showcase its versatility, as various NP types are biofunctionalized, including liposomes, PLGA NPs, and ultrasmall silica-based NPs, and the VHHs targeting of known TAAs (HER2 for breast cancer, CD38 for multiple myeloma), and an immune cell antigen (NKG2D for natural killer (NK) cells) is evaluated. In in vivo studies using a HER2+ breast cancer mouse model, the approach demonstrates enhanced tumor uptake, retention, and penetration compared to the behavior of nontargeted analogs, affirming its potential for diverse applications.

Subcutaneous Administration of a Zwitterionic Chitosan-Based Hydrogel for Controlled Spatiotemporal Release of Monoclonal Antibodies.

Subcutaneous (SC) administration of monoclonal antibodies (mAbs) is a proven strategy for improving therapeutic outcomes and patient compliance. The current FDA-/EMA-approved enzymatic approach, utilizing recombinant human hyaluronidase (rHuPH20) to enhance mAbs SC delivery, involves degrading the extracellular matrix's hyaluronate to increase tissue permeability. However, this method lacks tunable release properties, requiring individual optimization for each mAb. Seeking alternatives, physical polysaccharide hydrogels emerge as promising candidates due to their tunable physicochemical and biodegradability features. Unfortunately, none have demonstrated simultaneous biocompatibility, biodegradability, and controlled release properties for large proteins (≥150 kDa) after SC delivery in clinical settings. Here, a novel two-component hydrogel comprising chitosan and chitosan@DOTAGA is introduced that can be seamlessly mixed with sterile mAbs formulations initially designed for intravenous (IV) administration, repurposing them as novel tunable SC formulations. Validated in mice and nonhuman primates (NHPs) with various mAbs, including trastuzumab and rituximab, the hydrogel exhibited biodegradability and biocompatibility features. Pharmacokinetic studies in both species demonstrated tunable controlled release, surpassing the capabilities of rHuPH20, with comparable parameters to the rHuPH20+mAbs formulation. These findings signify the potential for rapid translation to human applications, opening avenues for the clinical development of this novel SC biosimilar formulation.

Clinically Translatable Transcrocetin Delivery Platform for Correction of Tumor Hypoxia and Enhancement of Radiation Therapy Effects.

Improving the tumor reoxygenation to sensitize the tumor to radiation therapy is a cornerstone in radiation oncology. Here, the pre-clinical development of a clinically transferable liposomal formulation encapsulating trans sodium crocetinate (NP TSC) is reported to improve oxygen diffusion through the tumor environment. Early pharmacokinetic analysis of the clinical trial of this molecule performed on 37 patients orient to define the optimal fixed dosage to use in a triple-negative breast cancer model to validate the therapeutic combination of radiation therapy and NP TSC. Notably, it is reported that this formulation is non-toxic in both humans and mice at the defined fixed concentration, provides a normalization of the tumor vasculature within 72 h window after systemic injection, leads to a transient increase (50% improvement) in the tumor oxygenation, and significantly improves the efficacy of both mono-fractionated and fractionated radiation therapy treatment. Together, these findings support the introduction of a first-in-class therapeutic construct capable of tumor-specific reoxygenation without associated toxicities.

Molecular bottlebrush prodrugs as mono- and triplex combination therapies for multiple myeloma.

Cancer therapies often have narrow therapeutic indexes and involve potentially suboptimal combinations due to the dissimilar physical properties of drug molecules. Nanomedicine platforms could address these challenges, but it remains unclear whether synergistic free-drug ratios translate to nanocarriers and whether nanocarriers with multiple drugs outperform mixtures of single-drug nanocarriers at the same dose. Here we report a bottlebrush prodrug (BPD) platform designed to answer these questions in the context of multiple myeloma therapy. We show that proteasome inhibitor (bortezomib)-based BPD monotherapy slows tumour progression in vivo and that mixtures of bortezomib, pomalidomide and dexamethasone BPDs exhibit in vitro synergistic, additive or antagonistic patterns distinct from their corresponding free-drug counterparts. BPDs carrying a statistical mixture of three drugs in a synergistic ratio outperform the free-drug combination at the same ratio as well as a mixture of single-drug BPDs in the same ratio. Our results address unanswered questions in the field of nanomedicine, offering design principles for combination nanomedicines and strategies for improving current front-line monotherapies and combination therapies for multiple myeloma.

Anti-BCMA Immuno-NanoPET Radiotracers for Improved Detection of Multiple Myeloma.

Current clinical imaging modalities for the sensitive and specific detection of multiple myeloma (MM) rely on nonspecific imaging contrast agents based on gadolinium chelates for magnetic resonance imaging (MRI) or for 18 F-FDG-directed and combined positron emission tomography (PET) and computed tomography (CT) scans. These tracers are not, however, able to detect minute plasma cell populations in the tumor niche, leading to false negative results. Here, a novel PET-based anti-BCMA nanoplatform labeled with 64 Cu is developed to improve the monitoring of these cells in both the spine and femur and to compare its sensitivity and specificity to more conventional immunoPET (64 Cu labeled anti-BCMA antibody) and passively targeted PET radiotracers (64 CuCl2 and 18 F-FDG). This proof-of-concept preclinical study confirmed that by conjugating up to four times more radioisotopes per antibody with the immuno-nanoPET platform, an improvement in the sensitivity and in the specificity of PET to detect tumor cells in an orthotopic model of MM is observed when compared to the traditional immunoPET approach. It is anticipated that when combined with tumor biopsy, this immuno-nanoPET platform may improve the management of patients with MM.

Synthesis and antiproliferative activity of 6BrCaQ-TPP conjugates for targeting the mitochondrial heat shock protein TRAP1.

A series of 6BrCaQ-Cn-TPP conjugates 3a-f and 5 was designed and synthesized as a novel class of TRAP1 inhibitors. Compound 3a displayed an excellent anti-proliferative activity with mean GI50 values at a nanomolar level in a diverse set of human cancer cells (GI50 = 0.008-0.30 µM) including MDA-MB231, HT-29, HCT-116, K562, and PC-3 cancer cell lines. Moreover, the best lead compound 6BrCaQ-C10-TPP induces a significant mitochondrial membrane disturbance combined to a regulation of HSP and partner protein levels as a first evidence that his mechanism of action involves the TRAP-1 mitochondrial Hsp90 machinery.

Anti-MUC1-C Antibody-Conjugated Nanoparticles Potentiate the Efficacy of Fractionated Radiation Therapy.

PURPOSE: Heavy-metal chelators and inorganic nanoparticles (NPs) have been examined as potential radioenhancers to increase the efficacy of external beam radiation therapy for various cancers. Most of these agents have, unfortunately, displayed relatively poor pharmacokinetic properties, which limit the percentage of injected dose (%ID/g) that localizes to tumors and which shorten the window for effective radiation enhancement due to rapid tumor washout. METHODS AND MATERIALS: To address these challenges, we sought to conjugate gadolinium-based ultrasmall (<5 nm) NPs to an antibody directed against the oncogenic MUC1-C subunit that is overexpressed on the surface of many different human cancer types. The binding of the anti-MUC1-C antibody 3D1 to MUC1-C on the surface of a cancer cell is associated with its internalization and, thereby, to effective intracellular delivery of the antibody-associated payload, promoting its effective tumor retention. As such, we examined whether systemically administered anti-MUC1-C antibody-conjugated, gadolinium-based NPs (anti-MUC1-C/NPs) could accumulate within cell-line xenograft models of MUC1-C-expressing (H460) lung and (E0771) breast cancers to improve the efficacy of radiation therapy (XRT). RESULTS: The %ID/g of anti-MUC1-C/NPs that accumulated within tumors was found to be similar to that of their unconjugated counterparts (6.6 ± 1.4 vs 5.9 ± 1.7 %ID/g, respectively). Importantly, the anti-MUC1-C/NPs demonstrated prolonged retention in in vivo tumor microenvironments; as a result, the radiation boost was maintained during the course of fractionated therapy (3 × 5.2 Gy). We found that by administering anti-MUC1-C/NPs with XRT, it was possible to significantly augment tumor growth inhibition and to prolong the animals' overall survival (46.2 ± 3.1 days) compared with the administration of control NPs with XRT (31.1 ± 2.4 days) or with XRT alone (27.3 ± 1.6 days; P < .01, log-rank). CONCLUSIONS: These findings suggest that anti-MUC1-C/NPs could be used to enhance the effectiveness of radiation therapy and potentially to improve clinical outcomes.

Pro-organic radical contrast agents ("pro-ORCAs") for real-time MRI of pro-drug activation in biological systems.

Nitroxide-based organic-radical contrast agents (ORCAs) are promising as safe, next-generation magnetic resonance imaging (MRI) tools. Nevertheless, stimuli-responsive ORCAs that enable MRI monitoring of prodrug activation have not been reported; such systems could open new avenues for prodrug validation and image-guided drug delivery. Here, we introduce a novel "pro-ORCA" concept that addresses this challenge. By covalent conjugation of nitroxides and drug molecules (doxorubicin, DOX) to the same brush-arm star polymer (BASP) through chemically identical cleavable linkers, we demonstrate that pro-ORCA and prodrug activation, i.e., ORCA and DOX release, leads to significant changes in MRI contrast that correlate with cytotoxicity. This approach is shown to be general for a range of commonly used linker cleavage mechanisms (e.g., photolysis and hydrolysis) and release rates. Pro-ORCAs could find applications as research tools or clinically viable "reporter theranostics" for in vitro and in vivo MRI-correlated prodrug activation.

Antibody-targeting of ultra-small nanoparticles enhances imaging sensitivity and enables longitudinal tracking of multiple myeloma.

Monitoring malignant progression and disease recurrence post-therapy are central challenges to improving the outcomes of patients with multiple myeloma (MM). Whereas current detection methods that rely upon bone marrow examination allow for precise monitoring of minimal residual disease and can help to elucidate clonal evolution, they do not take into account the spatial heterogeneity of the tumor microenvironment. As such, they are uninformative as to the localization of malignant plasma cells and may lead to false negative results. With respect to the latter challenge, clinically-available imaging agents are neither sufficiently sensitive nor specific enough to detect minute plasma cell populations. Here, we sought to explore methods by which to improve detection of MM cells within their natural bone marrow environment, using whole-animal magnetic resonance imaging to longitudinally monitor early-stage disease as well as to enhance tumor detection after systemic therapy. We conducted a proof-of-concept study to demonstrate that ultra-small (<5 nm) gadolinium-containing nanoparticles bound to full-length antibodies against the B-cell maturation antigen (BCMA) exhibit rapid tumor uptake followed by renal clearance, improving the signal-to-noise ratio for MM detection beyond levels that are currently afforded by other FDA-approved clinical imaging modalities. We anticipate that when combined with bone marrow or blood biopsy, such imaging constructs could help to augment the effective management of patients with MM.

Cancer drug resistance: rationale for drug delivery systems and targeted inhibition of HSP90 family proteins.

Nanocarriers have been developed in order to protect drugs or to improve drugs efficiency by reaching the damaged tissue and avoiding systemic and local toxicity. By using HSP90 inhibitors, some cancer drug resistances have been overcome and the loading into nanocarriers of such drugs has shown an increase of their activities. This review will present some advantages of HSP90 inhibitors to treat resistant tumors; especially those targeting the mitochondrial protein TRAP1. We will also focus on the targeting of the primary tumors, cancer stem cells and metastatic cells.

Triply Loaded Nitroxide Brush-Arm Star Polymers Enable Metal-Free Millimetric Tumor Detection by Magnetic Resonance Imaging.

Nitroxides occupy a privileged position among plausible metal-free magnetic resonance imaging (MRI) contrast agents (CAs) due to their inherently low-toxicity profiles; nevertheless, their translational development has been hindered by a lack of appropriate contrast sensitivity. Nanostructured materials with high nitroxide densities, where each individual nitroxide within a macromolecular construct contributes to the image contrast, could address this limitation, but the synthesis of such materials remains challenging. Here, we report a modular and scalable synthetic approach to nitroxide-based brush-arm star polymer (BASP) organic radical CAs (ORCAs) with high nitroxide loadings. The optimized ∼30 nm diameter "BASP-ORCA3" displays outstanding T2 sensitivity with a very high molecular transverse relaxivity ( r2 > 1000 mM-1 s-1). BASP-ORCA3 further exhibits excellent stability in vivo, no acute toxicity, and highly desirable pharmacokinetic and biodistribution profiles for longitudinal detection of tumors by MRI. When injected intravenously into mice bearing subcutaneous plasmacytomas, BASP-ORCA3 affords distinct in vivo visualization of tumors on translationally relevant time scales. Leveraging its high sensitivity, BASP-ORCA3 enables efficient mapping of tumor necrosis, which is an important biomarker to predict therapeutic outcomes. Moreover, BASP-ORCA3 allows for detection of millimetric tumor implants in a disseminated murine model of advanced-stage human ovarian cancer that possess genetic, histological, and vascular characteristics that are similar to those seen in patients. This work establishes BASP-ORCA3 as a promising metal-free spin contrast agent for MRI.

Ultrasmall AGuIX theranostic nanoparticles for vascular-targeted interstitial photodynamic therapy of glioblastoma.

Despite combined treatments, glioblastoma outcome remains poor with frequent local recurrences, indicating that a more efficient and local therapy is needed. In this way, vascular-targeted photodynamic therapy (VTP) could help tumor eradication by destroying its neovessels. In this study, we designed a polysiloxane-based nanoparticle (NP) combining a magnetic resonance imaging (MRI) contrast agent, a photosensitizer (PS) and a new ligand peptide motif (KDKPPR) targeting neuropilin-1 (NRP-1), a receptor overexpressed by angiogenic endothelial cells of the tumor vasculature. This structure achieves the detection of the tumor tissue and its proliferating part by MRI analysis, followed by its treatment by VTP. The photophysical properties of the PS and the peptide affinity for NRP-1 recombinant protein were preserved after the functionalization of NPs. Cellular uptake of NPs by human umbilical vein endothelial cells (HUVEC) was increased twice compared to NPs without the KDKPPR peptide moiety or conjugated with a scramble peptide. NPs induced no cytotoxicity without light exposure but conferred a photocytotoxic effect to cells after photodynamic therapy (PDT). The in vivo selectivity, evaluated using a skinfold chamber model in mice, confirms that the functionalized NPs with KDKPPR peptide moiety were localized in the tumor vessel wall.