Polymer-Functionalized Mitochondrial Transplantation to Fibroblasts Counteracts a Pro-Fibrotic Phenotype.

Fibroblast-to-myofibroblast transition (FMT) leads to excessive extracellular matrix (ECM) deposition-a well-known hallmark of fibrotic disease. Transforming growth factor-ß (TGF-ß) is the primary cytokine driving FMT, and this phenotypic conversion is associated with mitochondrial dysfunction, notably a metabolic reprogramming towards enhanced glycolysis. The objective of this study was to examine whether the establishment of favorable metabolic phenotypes in TGF-ß-stimulated fibroblasts could attenuate FMT. The hypothesis was that mitochondrial replenishment of TGF-ß-stimulated fibroblasts would counteract a shift towards glycolytic metabolism, consequently offsetting pro-fibrotic processes. Isolated mitochondria, functionalized with a dextran and triphenylphosphonium (TPP) (Dex-TPP) polymer conjugate, were administered to fibroblasts (MRC-5 cells) stimulated with TGF-ß, and effects on bioenergetics and fibrotic programming were subsequently examined. Results demonstrate that TGF-ß stimulation of fibroblasts led to FMT, which was associated with enhanced glycolysis. Dex-TPP-coated mitochondria (Dex-TPP/Mt) delivery to TGF-ß-stimulated fibroblasts abrogated a metabolic shift towards glycolysis and led to a reduction in reactive oxygen species (ROS) generation. Importantly, TGF-ß-stimulated fibroblasts treated with Dex-TPP/Mt had lessened expression of FMT markers and ECM proteins, as well as reduced migration and proliferation. Findings highlight the potential of mitochondrial transfer, as well as other strategies involving functional reinforcement of mitochondria, as viable therapeutic modalities in fibrosis.

Development of lung metastases in mouse models of tongue squamous cell carcinoma.

OBJECTIVE: Oral squamous cell carcinoma (OSCC) represents 3%-4% of all cancers. Despite the increasing incidence of OSCC distant metastasis and poor prognosis, few animal models of OSCC distant metastasis have been reported. In this study, we established mouse models of OSCC lung metastasis by orthotopic and tail vein injection of new OSCC cell lines. METHODS: For the tail vein model, we used a novel cell line isolated from lung metastases reproduced in vivo after intravenous injection of HSC-3 GFP/luciferase cells and sorted for GFP expression (HSC-3 M1 GFP/luciferase). Lung metastases were assessed by imaging techniques and further confirmed by histology. For the orthotopic model, HSC-3 GFP/luciferase cells were injected into the tongue of athymic nude mice. The primary tumor and metastases were assessed by in vivo imaging, histology, and immunohistochemistry. RESULTS: The orthotopic model presented spontaneous lung metastases in 50% of the animals and lymph node metastases were present in 83% of cases. In the tail vein model, a lung metastasis rate of 60% was observed. CONCLUSIONS: Lung metastases were successfully reproduced by orthotopic and tail vein injection. Since lymph node metastases were present, the orthotopic model with HSC-3 GFP/luciferase cells may be suitable to investigate metastatic dissemination in OSCC.

Functionalization of endovascular devices with superparamagnetic iron oxide nanoparticles for interventional cardiovascular magnetic resonance imaging.

Presently, cardiovascular interventions such as stent deployment and balloon angioplasty are performed under x-ray guidance. However, x-ray fluoroscopy has poor soft tissue contrast and is limited by imaging in a single plane, resulting in imprecise navigation of endovascular instruments. Moreover, x-ray fluoroscopy exposes patients to ionizing radiation and iodinated contrast agents. Magnetic resonance imaging (MRI) is a safe and enabling modality for cardiovascular interventions. Interventional cardiovascular MR (iCMR) is a promising approach that is in stark contrast with x-ray fluoroscopy, offering high-resolution anatomic and physiologic information and imaging in multiple planes for enhanced navigational accuracy of catheter-based devices, all in an environment free of radiation and its deleterious effects. While iCMR has immense potential, its translation into the clinical arena is hindered by the limited availability of MRI-visible catheters, wire guides, angioplasty balloons, and stents. Herein, we aimed to create application-specific, devices suitable for iCMR, and demonstrate the potential of iCMR by performing cardiovascular catheterization procedures using these devices. Tools, including catheters, wire guides, stents, and angioplasty balloons, for endovascular interventions were functionalized with a polymer coating consisting of poly(lactide-co-glycolide) (PLGA) and superparamagnetic iron oxide (SPIO) nanoparticles, followed by endovascular deployment in the pig. Findings from this study highlight the ability to image and properly navigate SPIO-functionalized devices, enabling interventions such as successful stent deployment under MRI guidance. This study demonstrates proof-of-concept for rapid prototyping of iCMR-specific endovascular interventional devices that can take advantage of the capabilities of iCMR.

Enzyme-responsive multistage vector for drug delivery to tumor tissue.

Various nanodelivery systems have been designed to release therapeutic agents upon contact with specific enzymes. However, enzyme-triggered release typically takes place in the tissue interstitium, thereby resulting in the extracellular delivery of drugs. Here, we have designed an enzyme-stimulated multistage vector (ESMSV), which enables stimulus-triggered release of drug-encapsulated nanoparticles from a microparticle. Specifically, polymeric nanoparticles with a surface matrix metalloproteinase-2 (MMP2) peptide substrate were conjugated to the surface of porous silicon microparticles. In the presence of MMP2, the polymeric nanoparticles were released into the tumor interstitium. This platform can be used to attain triggered drug release, while simultaneously facilitating the cellular internalization of drugs. The results indicate that nanoparticle release was MMP2-specific and resulted in improved intracellular uptake of hydrophobic agents in the presence of MMP2. Furthermore, in a mouse model of melanoma lung metastasis, systemic delivery of ESMSVs caused a substantial increase in intracellular accumulation of agents in cancer cells in comparison to delivery with non-stimulus-responsive particles.

A pyruvate decarboxylase-mediated therapeutic strategy for mimicking yeast metabolism in cancer cells.

Cancer cells have high rates of glycolysis and lactic acid fermentation in order to fuel accelerated rates of cell division (Warburg effect). Here, we present a strategy for merging cancer and yeast metabolism to remove pyruvate, a key intermediate of cancer cell metabolism, and produce the toxic compound acetaldehyde. This approach was achieved by administering the yeast enzyme pyruvate decarboxylase to triple negative breast cancer cells. To overcome the challenges of protein delivery, a nanoparticle-based system consisting of cationic lipids and porous silicon were employed to obtain efficient intracellular uptake. The results demonstrate that the enzyme therapy decreases cancer cell viability through production of acetaldehyde and reduction of lactic acid fermentation.

Inhibition of iNOS as a novel effective targeted therapy against triple-negative breast cancer.

INTRODUCTION: Triple-negative breast cancer (TNBC) is an aggressive form of breast cancer with no effective targeted therapy. Inducible nitric oxide synthase (iNOS) is associated with poor survival in patients with breast cancer by increasing tumor aggressiveness. This work aimed to investigate the potential of iNOS inhibitors as a targeted therapy for TNBC. We hypothesized that inhibition of endogenous iNOS would decrease TNBC aggressiveness by reducing tumor initiation and metastasis through modulation of epithelial-mesenchymal transition (EMT)-inducing factors. METHODS: iNOS protein levels were determined in 83 human TNBC tissues and correlated with clinical outcome. Proliferation, mammosphere-forming efficiency, migration, and EMT transcription factors were assessed in vitro after iNOS inhibition. Endogenous iNOS targeting was evaluated as a potential therapy in TNBC mouse models. RESULTS: High endogenous iNOS expression was associated with worse prognosis in patients with TNBC by gene expression as well as immunohistochemical analysis. Selective iNOS (1400 W) and pan-NOS (L-NMMA and L-NAME) inhibitors diminished cell proliferation, cancer stem cell self-renewal, and cell migration in vitro, together with inhibition of EMT transcription factors (Snail, Slug, Twist1, and Zeb1). Impairment of hypoxia-inducible factor 1α, endoplasmic reticulum stress (IRE1α/XBP1), and the crosstalk between activating transcription factor 3/activating transcription factor 4 and transforming growth factor ß was observed. iNOS inhibition significantly reduced tumor growth, the number of lung metastases, tumor initiation, and self-renewal. CONCLUSIONS: Considering the effectiveness of L-NMMA in decreasing tumor growth and enhancing survival rate in TNBC, we propose a targeted therapeutic clinical trial by re-purposing the pan-NOS inhibitor L-NMMA, which has been extensively investigated for cardiogenic shock as an anti-cancer therapeutic.

Chloroquine eliminates cancer stem cells through deregulation of Jak2 and DNMT1.

Triple negative breast cancer (TNBC) is known to contain a high percentage of CD44(+) /CD24(-/low) cancer stem cells (CSCs), corresponding with a poor prognosis despite systemic chemotherapy. Chloroquine (CQ), an antimalarial drug, is a lysotropic reagent which inhibits autophagy. CQ was identified as a potential CSC inhibitor through in silico gene expression signature analysis of the CD44(+) /CD24(-/low) CSC population. Autophagy plays a critical role in adaptation to stress conditions in cancer cells, and is related with drug resistance and CSC maintenance. Thus, the objectives of this study were to examine the potential enhanced efficacy arising from addition of CQ to standard chemotherapy (paclitaxel) in TNBC and to identify the mechanism by which CQ eliminates CSCs in TNBCs. Herein, we report that CQ sensitizes TNBC cells to paclitaxel through inhibition of autophagy and reduces the CD44(+) /CD24(-/low) CSC population in both preclinical and clinical settings. Also, we are the first to report a mechanism by which CQ regulates the CSCs in TNBC through inhibition of the Janus-activated kinase 2 (Jak2)-signal transducer and activator of transcription 3 signaling pathway by reducing the expression of Jak2 and DNA methyltransferase 1.

Mass partitioning effects in diffusion transport.

Frequent mass exchange takes place in a heterogeneous environment among several phases, where mass partitioning may occur at the interface of phases. Analytical and computational methods for diffusion do not usually incorporate molecule partitioning masking the true picture of mass transport. Here we present a computational finite element methodology to calculate diffusion mass transport with a partitioning phenomenon included and the analysis of the effects of partitioning. Our numerical results showed that partitioning controls equilibrated mass distribution as expected from analytical solutions. The experimental validation of mass release from drug-loaded nanoparticles showed that partitioning might even dominate in some cases with respect to diffusion itself. The analysis of diffusion kinetics in the parameter space of partitioning and diffusivity showed that partitioning is an extremely important parameter in systems, where mass diffusivity is fast and that the concentration of nanoparticles can control payload retention inside nanoparticles. The computational and experimental results suggest that partitioning and physiochemical properties of phases play an important, if not crucial, role in diffusion transport and should be included in the studies of mass transport processes.

Colocalized delivery of rapamycin and paclitaxel to tumors enhances synergistic targeting of the PI3K/Akt/mTOR pathway.

Ongoing clinical trials target the aberrant PI3K/Akt/mammalian target of rapamycin (mTOR) pathway in breast cancer through administration of rapamycin, an allosteric mTOR inhibitor, in combination with paclitaxel. However, synergy may not be fully exploited clinically because of distinct pharmacokinetic parameters of drugs. This study explores the synergistic potential of site-specific, colocalized delivery of rapamycin and paclitaxel through nanoparticle incorporation. Nanoparticle drug loading was accurately controlled, and synergistic drug ratios established in vitro. Precise drug ratios were maintained in tumors 48 hours after nanoparticle administration to mice, at levels twofold greater than liver and spleen, yielding superior antitumor activity compared to controls. Simultaneous and preferential in vivo delivery of rapamycin and paclitaxel to tumors yielded mechanistic insights into synergy involving suppression of feedback loop Akt phosphorylation and its downstream targets. Findings demonstrate that a same time, same place, and specific amount approach to combination chemotherapy by means of nanoparticle delivery has the potential to successfully translate in vitro synergistic findings in vivo. Predictive in vitro models can be used to determine optimum drug ratios for antitumor efficacy, while nanoparticle delivery of combination chemotherapies in preclinical animal models may lead to enhanced understanding of mechanisms of synergy, ultimately opening several avenues for personalized therapy.

Lipid nanoparticle-mediated mRNA delivery in lung fibrosis.

mRNA delivery enables the specific synthesis of proteins with therapeutic potential, representing a powerful strategy in diseases lacking efficacious pharmacotherapies. Idiopathic pulmonary fibrosis (IPF) is a chronic lung disease characterized by excessive extracellular matrix (ECM) deposition and subsequent alveolar remodeling. Alveolar epithelial type 2 cells (AEC2) and fibroblasts represent important targets in IPF given their role in initiating and driving aberrant wound healing responses that lead to excessive ECM deposition. Our objective was to examine a lipid nanoparticle (LNP)-based mRNA construct as a viable strategy to target alveolar epithelial cells and fibroblasts in IPF. mRNA-containing LNPs measuring ∼34 nm had high encapsulation efficiency, protected mRNA from degradation, and exhibited sustained release kinetics. eGFP mRNA LNP transfection in human primary cells proved dose- and time-dependent in vitro. In a bleomycin mouse model of lung fibrosis, luciferase mRNA LNPs administered intratracheally led to site-specific lung accumulation. Importantly, bioluminescence signal was detected in lungs as early as 2 h after delivery, with signal still evident at 48 h. Of note, LNPs were found associated with AEC2 and fibroblasts in vivo. Findings highlight the potential for pulmonary delivery of mRNA in IPF, opening therapeutic avenues aimed at halting and potentially reversing disease progression.

Multi-stage delivery nano-particle systems for therapeutic applications.

BACKGROUND: The daunting task for drug molecules to reach pathological lesions has fueled rapid advances in Nanomedicine. The progressive evolution of nanovectors has led to the development of multi-stage delivery systems aimed at overcoming the numerous obstacles encountered by nanovectors on their journey to the target site. SCOPE OF REVIEW: This review summarizes major findings with respect to silicon-based drug delivery vectors for cancer therapeutics and imaging. Based on rational design, well-established silicon technologies have been adapted for the fabrication of nanovectors with specific shapes, sizes, and porosities. These vectors are part of a multi-stage delivery system that contains multiple nano-components, each designed to achieve a specific task with the common goal of site-directed delivery of therapeutics. MAJOR CONCLUSIONS: Quasi-hemispherical and discoidal silicon microparticles are superior to spherical particles with respect to margination in the blood, with particles of different shapes and sizes having unique distributions in vivo. Cellular adhesion and internalization of silicon microparticles is influenced by microparticle shape and surface charge, with the latter dictating binding of serum opsonins. Based on in vitro cell studies, the internalization of porous silicon microparticles by endothelial cells and macrophages is compatible with cellular morphology, intracellular trafficking, mitosis, cell cycle progression, cytokine release, and cell viability. In vivo studies support superior therapeutic efficacy of liposomal encapsulated siRNA when delivered in multi-stage systems compared to free nanoparticles. This article is part of a Special Issue entitled Nanotechnologies - Emerging Applications in Biomedicine.

Gadolinium metallofullerenol nanoparticles inhibit cancer metastasis through matrix metalloproteinase inhibition: imprisoning instead of poisoning cancer cells.

The purpose of this work is to study the antimetastasis activity of gadolinium metallofullerenol nanoparticles (f-NPs) in malignant and invasive human breast cancer models. We demonstrated that f-NPs inhibited the production of matrix metalloproteinase (MMP) enzymes and further interfered with the invasiveness of cancer cells in tissue culture condition. In the tissue invasion animal model, the invasive primary tumor treated with f-NPs showed significantly less metastasis to the ectopic site along with the decreased MMP expression. In the same animal model, we observed the formation of a fibrous cage that may serve as a physical barrier capable of cancer tissue encapsulation that cuts the communication between cancer- and tumor-associated macrophages, which produce MMP enzymes. In another animal model, the blood transfer model, f-NPs potently suppressed the establishment of tumor foci in lung. Based on these data, we conclude that f-NPs have antimetastasis effects and speculate that utilization of f-NPs may provide a new strategy for the treatment of tumor metastasis. FROM THE CLINICAL EDITOR: In this study utilizing metallofullerenol nanoparticles, the authors demonstrate antimetastasis effects and speculate that utilization of these nanoparticles may provide a new strategy in metastatic tumor therapy.

Targeting the Meningeal Compartment to Resolve Chemobrain and Neuropathy via Nasal Delivery of Functionalized Mitochondria.

Cognitive deficits (chemobrain) and peripheral neuropathy occur in ∼75% of patients treated for cancer with chemotherapy and persist long-term in >30% of survivors. Without preventive or curative interventions and with increasing survivorship rates, the population debilitated by these neurotoxicities is rising. Platinum-based chemotherapeutics, including cisplatin, induce neuronal mitochondrial defects leading to chemobrain and neuropathic pain. This study investigates the capacity of nasally administered mesenchymal stem cell-derived mitochondria coated with dextran-triphenylphosphonium polymer (coated mitochondria) to reverse these neurotoxicities. Nasally administered coated mitochondria are rapidly detectable in macrophages in the brain meninges but do not reach the brain parenchyma. The coated mitochondria change expression of >2400 genes regulating immune, neuronal, endocrine and vascular pathways in the meninges of mice treated with cisplatin. Nasal administration of coated mitochondria reverses cisplatin-induced cognitive deficits and resolves neuropathic pain at a >55-times lower dose compared to uncoated mitochondria. Reversal of these neuropathologies is associated with resolution of cisplatin-induced deficits in myelination, synaptosomal mitochondrial integrity and neurogenesis. These findings demonstrate that nasally administered coated mitochondria promote resolution of chemobrain and peripheral neuropathy, thereby identifying a novel facile strategy for clinical application of mitochondrial donation and treating central and peripheral nervous system pathologies by targeting the brain meninges.

Nanomedicine in cancer therapy: innovative trends and prospects.

Cancer is a leading cause of morbidity and mortality worldwide, with recent advancements resulting in modest impacts on patient survival. Nanomedicine represents an innovative field with immense potential for improving cancer treatment, having ushered in several established drug delivery platforms. Nanoconstructs such as liposomes are widely used in clinics, while polymer micelles are in advanced phases of clinical trials in several countries. Currently, the field of nanomedicine is generating a new wave of nanoscale drug delivery strategies, embracing trends that involve the functionalization of these constructs with moieties that enhance site-specific delivery and tailored release. Herein, we discuss several advancements in established nanoparticle technologies such as liposomes, polymer micelles, and dendrimers regarding tumor targeting and controlled release strategies, which are being incorporated into their design with the hope of generating a more robust and efficacious nanotherapeutic modality. We also highlight a novel strategy known as multistage drug delivery; a rationally designed nanocarrier aimed at overcoming numerous biological barriers involved in drug delivery through the decoupling of various tasks that comprise the journey from the moment of systemic administration to arrival at the tumor site.

Proteomic analysis of serum opsonins impacting biodistribution and cellular association of porous silicon microparticles.

Mass transport of drug delivery vehicles is guided by particle properties, such as size, shape, composition, and surface chemistry, as well as biomolecules and serum proteins that adsorb to the particle surface. In an attempt to identify serum proteins influencing cellular associations and biodistribution of intravascularly injected particles, we used two-dimensional gel electrophoresis and mass spectrometry to identify proteins eluted from the surface of cationic and anionic silicon microparticles. Cationic microparticles displayed a 25-fold greater abundance of Ig light variable chain, fibrinogen, and complement component 1 compared to their anionic counterparts. Anionic microparticles were found to accumulate in equal abundance in murine liver and spleen, whereas cationic microparticles showed preferential accumulation in the spleen. Immunohistochemistry supported macrophage uptake of both anionic and cationic microparticles in the liver, as well as evidence of association of cationic microparticles with hepatic endothelial cells. Furthermore, scanning electron micrographs supported cellular competition for cationic microparticles by endothelial cells and macrophages. Despite high macrophage content in the lungs and tumor, microparticle uptake by these cells was minimal, supporting differences in the repertoire of surface receptors expressed by tissue-specific macrophages. In summary, particle surface chemistry drives selective binding of serum components impacting cellular interactions and biodistribution.

Enabling individualized therapy through nanotechnology.

Individualized medicine is the healthcare strategy that rebukes the idiomatic dogma of 'losing sight of the forest for the trees'. We are entering a new era of healthcare where it is no longer acceptable to develop and market a drug that is effective for only 80% of the patient population. The emergence of "-omic" technologies (e.g. genomics, transcriptomics, proteomics, metabolomics) and advances in systems biology are magnifying the deficiencies of standardized therapy, which often provide little treatment latitude for accommodating patient physiologic idiosyncrasies. A personalized approach to medicine is not a novel concept. Ever since the scientific community began unraveling the mysteries of the genome, the promise of discarding generic treatment regimens in favor of patient-specific therapies became more feasible and realistic. One of the major scientific impediments of this movement towards personalized medicine has been the need for technological enablement. Nanotechnology is projected to play a critical role in patient-specific therapy; however, this transition will depend heavily upon the evolutionary development of a systems biology approach to clinical medicine based upon "-omic" technology analysis and integration. This manuscript provides a forward looking assessment of the promise of nanomedicine as it pertains to individualized medicine and establishes a technology "snapshot" of the current state of nano-based products over a vast array of clinical indications and range of patient specificity. Other issues such as market driven hurdles and regulatory compliance reform are anticipated to "self-correct" in accordance to scientific advancement and healthcare demand. These peripheral, non-scientific concerns are not addressed at length in this manuscript; however they do exist, and their impact to the paradigm shifting healthcare transformation towards individualized medicine will be critical for its success.

Intratumoral delivery of beta-lapachone via polymer implants for prostate cancer therapy.

PURPOSE: beta-Lapachone (ARQ 501, a formulation of beta-lapachone complexed with hydroxypropyl-beta-cyclodextrin) is a novel anticancer agent with selectivity against prostate cancer cells overexpressing the NAD(P)H:quinone oxidoreductase-1 enzyme. Lack of solubility and an efficient drug delivery strategy limits this compound in clinical applications. In this study, we aimed to develop beta-lapachone-containing polymer implants (millirods) for direct implantation into prostate tumors to test the hypothesis that the combination of a tumor-specific anticancer agent with site-specific release of the agent will lead to significant antitumor efficacy. EXPERIMENTAL DESIGN: Survival assays in vitro were used to test the killing effect of beta-lapachone in different prostate cancer cells. beta-Lapachone release kinetics from millirods was determined in vitro and in vivo. PC-3 prostate tumor xenografts in athymic nude mice were used for antitumor efficacy studies in vivo. RESULTS: beta-Lapachone killed three different prostate cancer cell lines in an NAD(P)H:quinone oxidoreductase-1-dependent manner. Upon incorporation of solid-state inclusion complexes of beta-lapachone with hydroxypropyl-beta-cyclodextrin into poly(D,L-lactide-co-glycolide) millirods, beta-lapachone release kinetics in vivo showed a burst release of approximately 0.5 mg within 12 hours and a subsequently sustained release of the drug ( approximately 0.4 mg/kg/d) comparable with that observed in vitro. Antitumor efficacy studies showed significant tumor growth inhibition by beta-lapachone millirods compared with controls (P < 0.0001; n = 10 per group). Kaplan-Meier survival curves showed that tumor-bearing mice treated with beta-lapachone millirods survived nearly 2-fold longer than controls, without observable systemic toxicity. CONCLUSIONS: Intratumoral delivery of beta-lapachone using polymer millirods showed the promising therapeutic potential for human prostate tumors.

Intratumoral injection of hydrogel-embedded nanoparticles enhances retention in glioblastoma.

Intratumoral drug delivery is a promising approach for the treatment of glioblastoma multiforme (GBM). However, drug washout remains a major challenge in GBM therapy. Our strategy, aimed at reducing drug clearance and enhancing site-specific residence time, involves the local administration of a multi-component system comprised of nanoparticles (NPs) embedded within a thermosensitive hydrogel (HG). Herein, our objective was to examine the distribution of NPs and their cargo following intratumoral administration of this system in GBM. We hypothesized that the HG matrix, which undergoes rapid gelation upon increases in temperature, would contribute towards heightened site-specific retention and permanence of NPs in tumors. BODIPY-containing, infrared dye-labeled polymeric NPs embedded in a thermosensitive HG (HG-NPs) were fabricated and characterized. Retention and distribution dynamics were subsequently examined over time in orthotopic GBM-bearing mice. Results demonstrate that the HG-NPs system significantly improved site-specific, long-term retention of both NPs and BODIPY, with co-localization analyses showing that HG-NPs covered larger areas of the tumor and the peri-tumor region at later time points. Moreover, NPs released from the HG were shown to undergo uptake by surrounding GBM cells. Findings suggest that intratumoral delivery with HG-NPs has immense potential for GBM treatment, as well as other strategies where site-specific, long-term retention of therapeutic agents is warranted.

Multifunctional micellar nanomedicine for cancer therapy.

Polymeric micelles are supramolecular, core-shell nanoparticles that offer considerable advantages for cancer diagnosis and therapy. Their relatively small size (10-100 nm), ability to solubilize hydrophobic drugs as well as imaging agents, and improved pharmacokinetics provide a useful bioengineering platform for cancer applications. Several polymeric micelle formulations are currently undergoing phase I/II clinical trials, which have shown improved antitumor efficacy and reduced systemic toxicity. This minireview will focus on recent advancements in the multifunctional design of micellar nanomedicine with tumor targeting, stimulated drug release, and cancer imaging capabilities. Such functionalization strategies result in enhanced micellar accumulation at tumor sites, higher drug bioavailability, as well as improved tumor diagnosis and visualization of therapy. Ultimately, integrated nanotherapeutic systems (e.g., theranostic nanomedicine) may prove essential to address the challenges of tumor heterogeneity and adaptive resistance to achieve efficacious treatment of cancer.

Systematic comparison of methods for determining the in vivo biodistribution of porous nanostructured injectable inorganic particles.

With a wide variety of biodistribution measurement techniques reported in the literature, it is important to perform side-by-side comparisons of results obtained with different methods on the same particle platform, to determine differences across methods, highlight advantages and disadvantages, and inform methods selection according to specific applications. Inorganic nanostructured particles (INPs) have gained a central role in the development of injectable delivery vectors thanks to their controllable design, biocompatibility, and favorable degradation kinetic. Thus, accurate determination of in vivo biodistribution of INPs is a key aspect of developing and optimizing this class of delivery vectors. In this study, a systematic comparison of spectroscopy (inductively coupled plasma optical emission spectroscopy), fluorescence (in vivo imaging system, confocal microscopy, and plate reader), and radiolabeling (gamma counter)-based techniques is performed to assess the accuracy and sensitivity of biodistribution measurements in mice. Each method is evaluated on porous silicon particles, an established and versatile injectable delivery platform. Biodistribution is evaluated in all major organs and compared in terms of absolute results (%ID/g and %ID/organ when possible) and sensitivity (σ%). Finally, we discuss how these results can be extended to inform method selection for other platforms and specific applications, with an outlook to potential benefit for pre-clinical and clinical studies. Overall, this study presents a new practical guide for selection of in vivo biodistribution methods that yield quantitative results. STATEMENT OF SIGNIFICANCE: The significance of this work lies in the use of a single platform to test performances of different biodistribution methods in vivo, with a strict quantitative metric. These results, united with the qualitative comparison of advantages and disadvantages of each technique, are aimed at supporting the rational choice of each different method according to the specific application, to improve the quantitative description of biodistribution results that will be published by others in the future.