Lysosomal-targeted doxorubicin delivery using RBC-derived vesicles to overcome drug-resistant cancer through mitochondrial-dependent cell death.

Multidrug resistance (MDR) is a major challenge in cancer chemotherapy. Nanoparticles as drug delivery systems (DDSs) show promise for MDR cancer therapy. However, current DDSs require sophisticated design and construction based on xenogeneic nanomaterials, evoking feasibility and biocompatibility concerns. Herein, a simple but versatile biological DDS (bDDS) composed of human red blood cell (RBC)-derived vesicles (RDVs) with excellent biocompatibility was surface-linked with doxorubicin (Dox) using glutaraldehyde (glu) to form Dox-gluRDVs that remarkably suppressed MDR in uterine sarcoma through a lysosomal-mitochondrial axis-dependent cell death mechanism. Dox-gluRDVs can efficiently deliver and accumulate Dox in lysosomes, bypassing drug efflux transporters and facilitating cellular uptake and retention of Dox in drug-resistant MES-SA/Dx5 cells. The transfer of lysosomal calcium to the mitochondria during mitochondria-lysosome contact due to lysosomal Dox accumulation may result in mitochondrial ROS overproduction, mitochondrial membrane potential loss, and activation of apoptotic signaling for the superior anti-MDR activity of Dox-gluRDVs in vitro and in vivo. This work highlights the great promise of RDVs to serve as a bDDS of Dox to overcome MDR cancers but also opens up a reliable strategy for lysosomal-mitochondrial axis-dependent cell death for fighting against other inoperable cancers.

A novel mouse model of sporadic colon cancer induced by combination of conditional Apc genes and chemical carcinogen in the absence of Cre recombinase.

Although valuable insights into colon cancer biology have been garnered from human colon cancer cell lines and primary colonic tissues, and animal studies using human colon cancer xenografts, immunocompetent mouse models of spontaneous or chemically induced colon cancer better phenocopy human disease. As most sporadic human colon tumors present adenomatous polyposis coli (APC) gene mutations, considerable effort has gone into developing mice that express mutant Apc alleles that mimic human colon cancer pathogenesis. A serious limitation of many of these Apc-mutant murine models, however, is that these mice develop numerous tumors in the small intestine but few, if any, in the colon. In this work, we examined three spontaneous mouse models of colon tumorigenesis based upon the widely used multiple intestinal neoplasia (Min) mouse: mice with either constitutive or conditional Apc mutations alone or in combination with caudal-related homeobox transcription factor CDX2P-Cre transgene - either with or without exposure to the potent colon carcinogen azoxymethane. Using the CDX2 promoter to drive Cre recombinase transgene expression effectively inactivated Apc in colonocytes, creating a model with earlier tumor onset and increased tumor incidence/burden, but without the Min mouse model's small intestine tumorigenesis and susceptibility to intestinal perforation/ulceration/hemorrhage. Most significantly, azoxymethane-treated mice with conditional Apc expression, but absent the Cre recombinase gene, demonstrated nearly 50% tumor incidence with two or more large colon tumors per mouse of human-like histology, but no small intestine tumors - unlike the azoxymethane-resistant C57BL/6J-background Min mouse model. As such this model provides a robust platform for chemoprevention studies.

Seeing Better and Going Deeper in Cancer Nanotheranostics.

Biomedical imaging modalities in clinical practice have revolutionized oncology for several decades. State-of-the-art biomedical techniques allow visualizing both normal physiological and pathological architectures of the human body. The use of nanoparticles (NP) as contrast agents enabled visualization of refined contrast images with superior resolution, which assists clinicians in more accurate diagnoses and in planning appropriate therapy. These desirable features are due to the ability of NPs to carry high payloads (contrast agents or drugs), increased in vivo half-life, and disease-specific accumulation. We review the various NP-based interventions for treatments of deep-seated tumors, involving "seeing better" to precisely visualize early diagnosis and "going deeper" to activate selective therapeutics in situ.

Microwave-Synthesized Platinum-Embedded Mesoporous Silica Nanoparticles as Dual-Modality Contrast Agents: Computed Tomography and Optical Imaging.

Nanoparticle-based imaging contrast agents have drawn tremendous attention especially in multi-modality imaging. In this study, we developed mesoporous silica nanoparticles (MSNs) for use as dual-modality contrast agents for computed tomography (CT) and near-infrared (NIR) optical imaging (OI). A microwave synthesis for preparing naked platinum nanoparticles (nPtNPs) on MSNs (MSNs-Pt) was developed and characterized with physicochemical analysis and imaging systems. The high density of nPtNPs on the surface of the MSNs could greatly enhance the CT contrast. Inductively coupled plasma mass spectrometry (ICP-MS) revealed the MSNs-Pt compositions to be ~14% Pt by weight and TEM revealed an average particle diameter of ~50 nm and covered with ~3 nm diameter nPtNPs. To enhance the OI contrast, the NIR fluorescent dye Dy800 was conjugated to the MSNs-Pt nanochannels. The fluorescence spectra of MSNs-Pt-Dy800 were very similar to unconjugated Dy800. The CT imaging demonstrated that even modest degrees of Pt labeling could result in substantial X-ray attenuation. In vivo imaging of breast tumor-bearing mice treated with PEGylated MSNs-Pt-Dy800 (PEG-MSNs-Pt-Dy800) showed significantly improved contrasts in both fluorescence and CT imaging and the signal intensity within the tumor retained for 24 h post-injection.

Evolution of Nanoparticle-Mediated Photodynamic Therapy: From Superficial to Deep-Seated Cancers.

Enthusiasm for photodynamic therapy (PDT) as a potential therapeutic intervention for cancer has increased exponentially in recent decades. Photodynamic therapy constitutes a clinically approved, minimally invasive treatment modality that uses a photosensitizer (light absorbing molecule) and light to kill cancer cells. The principle of PDT is, when irradiated with a light of a suitable wavelength, a photosensitizer absorbs the light energy and generates cytotoxic free radicals through various mechanisms. The overall efficiency of PDT depends on characteristics of activation light and in-situ dosimetry, including the choice of photosensitizer molecule, wavelength of the light, and tumor location and microenvironment, for instance, the use of two-photon laser or an X-ray irradiator as the light source increases tissue-penetration depth, enabling it to achieve deep PDT. In this mini-review, we discuss the various designs and strategies for single, two-photon, and X-ray-mediated PDT for improved clinical outcomes.

Lectin-functionalized mesoporous silica nanoparticles for endoscopic detection of premalignant colonic lesions.

Colorectal cancer (CRC) is one of the leading causes of cancer-deaths worldwide. Methods for the early in situ detection of colorectal adenomatous polyps and their precursors - prior to their malignancy transformation into CRC - are urgently needed. Unfortunately at present, the primary diagnostic method, colonoscopy, can only detect polyps and carcinomas by shape/morphology; with sessile polyps more likely to go unnoticed than polypoid lesions. Here we describe our development of polyp-targeting, fluorescently-labeled mesoporous silica nanoparticles (MSNs) that serve as targeted endoscopic contrast agents for the early detection of colorectal polyps and cancer. In vitro cell studies, ex vivo histopathological analysis, and in vivo colonoscopy and endoscopy of murine colorectal cancer models, demonstrate significant binding specificity of our nanoconstructs to pathological lesions via targeting aberrant α-L-fucose expression. Our findings strongly suggest that lectin-functionalized fluorescent MSNs could serve as a promising endoscopic contrast agent for in situ diagnostic imaging of premalignant colonic lesions.

Depicting Binding-Mediated Translocation of HIV-1 Tat Peptides in Living Cells with Nanoscale Pens of Tat-Conjugated Quantum Dots.

Cell-penetrating peptides (CPPs) can translocate across cell membranes, and thus have great potential for the cellular delivery of macromolecular cargoes. However, the mechanism of this cellular uptake process is not yet fully understood. In this study, a time-lapse single-particle light-sheet microscopy technique was implemented to obtain a parallel visualization of the translocating process of individual human immunodeficiency virus 1 (HIV-1) transactivator of transcription (Tat) peptide conjugated quantum dots (TatP-QDs) in complex cellular terrains. Here, TatP-QDs served as nanoscale dynamic pens, which depict remarkable trajectory aggregates of TatP-QDs on the cell surface. Spectral-embedding analysis of the trajectory aggregates revealed a manifold formed by isotropic diffusion and a fraction of directed movement, possibly caused by interaction between the Tat peptides and heparan sulfate groups on the plasma membrane. Further analysis indicated that the membrane deformation induced by Tat-peptide attachment increased with the disruption of the actin framework in cytochalasin D (cyto D)-treated cells, yielding higher interactions on the TatP-QDs. In native cells, the Tat peptides can remodel the actin framework to reduce their interaction with the local membrane environment. Characteristic hot spots for interaction were detected on the membrane, suggesting that a funnel passage may have formed for the Tat-coated particles. This finding offers valuable insight into the cellular delivery of nanoscale cargo, suggesting an avenue for direct therapeutic delivery.

Unraveling the impact of lipid domains on the dimerization processes of single-molecule EGFRs of live cells.

Epidermal growth factor receptor (EGFR/ErbB1) is a transmembrane protein that can drive cell growth and survival via the ligand-induced dimerization of receptors. Because dimerization is a common mechanism for signal transduction, it is important to improve our understanding of how the dimerization process and membrane structure regulate signal transduction. In this study, we examined the effect of lipid nanodomains on the dimerization process of EGFR molecules. We discovered that after ligand binding, EGFR molecules may move into lipid nanodomains. The lipid nanodomains surrounding two liganded EGFRs can merge during their correlated motion. The transition rates between different diffusion states of liganded EGFR molecules are regulated by the lipid domains. Our method successfully captures both the sensitivity of single-molecule processes and statistic accuracy of data analysis, providing insight into the connection between the mobile clustering process of receptors and the hierarchical structure of plasma membrane.

Energetic modeling and single-molecule verification of dynamic regulation on receptor complexes by actin corrals and lipid raft domains.

We developed an energetic model by integrating the generalized Langevin equation with the Cahn-Hilliard equation to simulate the diffusive behaviors of receptor proteins in the plasma membrane of a living cell. Simulation results are presented to elaborate the confinement effects from actin corrals and protein-induced lipid domains. Single-molecule tracking data of epidermal growth factor receptors (EGFR) acquired on live HeLa cells agree with the simulation results and the mechanism that controls the diffusion of single-molecule receptors is clarified. We discovered that after ligand binding, EGFR molecules move into lipid nanodomains. The transition rates between different diffusion states of liganded EGFR molecules are regulated by the lipid domains. Our method successfully captures dynamic interactions of receptors at the single-molecule level and provides insight into the functional architecture of both the diffusing EGFR molecules and their local cellular environment.

Nanoparticle-programmed self-destructive neural stem cells for glioblastoma targeting and therapy.

A 3-step glioblastoma-tropic delivery and therapy method using nanoparticle programmed self-destructive neural stem cells (NSCs) is demonstrated in vivo: 1) FDA-approved NSCs for clinical trials are loaded with pH-sensitive MSN-Dox; 2) the nanoparticle conjugates provide a delayed drug-releasing mechanism and allow for NSC migration towards a distant tumor site; 3) NSCs eventually undergo cell death and release impregnated MSN-Dox, which subsequently induces toxicity towards surrounding glioma cells.

Personalized Cancer Therapeutics Using Photoacoustic Imaging-Guided Sonodynamic Therapy.

Sonodynamic therapy (SDT) is a promising approach for cancer treatment that uses sonosensitizers (SNSs) to generate reactive oxygen species (ROS) in the presence of ultrasound (US). However, SDT is oxygen-dependent and requires an imaging tool to monitor the tumor microenvironment and guide treatment. Photoacoustic imaging (PAI) is a noninvasive and powerful imaging tool that offers high spatial resolution and deep tissue penetration. PAI can quantitatively assess tumor oxygen saturation (sO2) and guide SDT by monitoring time-dependent sO2 changes in the tumor microenvironment. Here, we discuss recent advances in PAI-guided SDT for cancer therapy. We discuss various exogenous contrast agents and nanomaterial-based SNSs developed for PAI-guided SDT. Additionally, combining SDT with other therapies, including photothermal (PTT) therapy, can enhance its therapeutic effect. However, the application of nanomaterial-based contrast agents in PAI-guided SDT for cancer therapy remains challenging due to the lack of simple designs, the need for extensive pharmacokinetic studies, and high production costs. Integrated efforts from researchers, clinicians, and industry consortia are necessary for the successful clinical translation of these agents and SDT for personalized cancer therapy. PAI-guided SDT shows the potential to revolutionize cancer therapy and improve patient outcomes, but further research is necessary to realize its full potential.

A Dual Concentration-Tailored Cytokine-Chemo Nanosystem to Alleviate Multidrug Resistance and Redirect Balance of Cancer Proliferation and Apoptosis.

Background: Cancer multidrug resistance (MDR) is an important factor that severely affects the chemotherapeutic efficacy. Among various methods to bypass MDR, usage of cytokines, such as tumor necrosis factor alpha (TNFα) is attractive, which exerts antitumor effects of immunotherapeutic response and apoptotic/proinflammatory pathways. Nevertheless, the challenges remain how to implement targeted delivery of TNFα to reduce toxicity and manifest the involved signaling mechanism that subdues MDR. Methods: We synthesized a multifunctional nanosytem, in which TNFα covalently bound to doxorubicin (Dox)-loaded pH-responsive mesoporous silica nanoparticles (MSN) through bi-functional polyethylene glycol (TNFα-PEG-MSN-Hydrazone-Dox) as a robust design to overcome MDR. Results: The salient features of this nanoplatform are: 1) by judicious tailoring of TNFα concentration conjugated on MSN, we observed it could lead to a contrary effect of either proliferation or suppression of tumor growth; 2) the MSN-TNFα at higher concentration serves multiple functions, besides tumor targeting and inducer of apoptosis through extrinsic pathway, it inhibits the expression level of p-glycoprotein (P-gp), a cell membrane protein that functions as a drug efflux pump; 3) the enormous surface area of MSN provides for TNFα functionalization, and the nanochannels accommodate chemotherapeutics, Dox; 4) targeted intracellular release of Dox through the pH-dependent cleavage of hydrazone bonds induces apoptosis by the specific intrinsic pathway; and 5) TNFα-PEG-MSN-Hydrazone-Dox (MSN-Dox-TNFα) could infiltrate deep into the 3D spheroid tumor model through disintegration of tight junction proteins. When administered intratumorally in a Dox-resistant mouse tumor model, MSN-Dox-TNFα exhibited a synergistic therapeutic effect through the collective performances of TNFα and Dox. Conclusion: We hereby develop and demonstrate a multifunctional MSN-Dox-TNFα system with concentration-tailored TNFα that can abrogate the drug resistance mechanism, and significantly inhibit the tumor growth through both intrinsic and extrinsic apoptosis pathways, thus making it a highly potential nanomedicine translated in the treatment of MDR tumors.

Illuminating and Radiosensitizing Tumors with 2DG-Bound Gold-Based Nanomedicine for Targeted CT Imaging and Therapy.

Although radiotherapy is one of the most important curative treatments for cancer, its clinical application is associated with undesired therapeutic effects on normal or healthy tissues. The use of targeted agents that can simultaneously achieve therapeutic and imaging functions could constitute a potential solution. Herein, we developed 2-deoxy-d-glucose (2DG)-labeled poly(ethylene glycol) (PEG) gold nanodots (2DG-PEG-AuD) as a tumor-targeted computed tomography (CT) contrast agent and radiosensitizer. The key advantages of the design are its biocompatibility and targeted AuD with excellent sensitivity in tumor detection via avid glucose metabolism. As a consequence, CT imaging with enhanced sensitivity and remarkable radiotherapeutic efficacy could be attained. Our synthesized AuD displayed linear enhancement of CT contrast as a function of its concentration. In addition, 2DG-PEG-AuD successfully demonstrated significant augmentation of CT contrast in both in vitro cell studies and in vivo tumor-bearing mouse models. In tumor-bearing mice, 2DG-PEG-AuD showed excellent radiosensitizing functions after intravenous injection. Results from this work indicate that 2DG-PEG-AuD could greatly potentiate theranostic capabilities by providing high-resolution anatomical and functional images in a single CT scan and therapeutic capability.

Recent advances in nanoparticle-based Förster resonance energy transfer for biosensing, molecular imaging and drug release profiling.

Förster resonance energy transfer (FRET) may be regarded as a "smart" technology in the design of fluorescence probes for biological sensing and imaging. Recently, a variety of nanoparticles that include quantum dots, gold nanoparticles, polymer, mesoporous silica nanoparticles and upconversion nanoparticles have been employed to modulate FRET. Researchers have developed a number of "visible" and "activatable" FRET probes sensitive to specific changes in the biological environment that are especially attractive from the biomedical point of view. This article reviews recent progress in bringing these nanoparticle-modulated energy transfer schemes to fruition for applications in biosensing, molecular imaging and drug delivery.

Assessment of Nanoparticle-Mediated Tumor Oxygen Modulation by Photoacoustic Imaging.

Photoacoustic imaging (PAI) is an invaluable tool in biomedical imaging, as it provides anatomical and functional information in real time. Its ability to image at clinically relevant depths with high spatial resolution using endogenous tissues as contrast agents constitutes its major advantage. One of the most important applications of PAI is to quantify tissue oxygen saturation by measuring the differential absorption characteristics of oxy and deoxy Hb. Consequently, PAI can be utilized to monitor tumor-related hypoxia, which is a crucial factor in tumor microenvironments that has a strong influence on tumor invasiveness. Reactive oxygen species (ROS)-based therapies, such as photodynamic therapy, radiotherapy, and sonodynamic therapy, are oxygen-consuming, and tumor hypoxia is detrimental to their efficacy. Therefore, a persistent demand exists for agents that can supply oxygen to tumors for better ROS-based therapeutic outcomes. Among the various strategies, NP-mediated supplemental tumor oxygenation is especially encouraging due to its physio-chemical, tumor targeting, and theranostic properties. Here, we focus on NP-based tumor oxygenation, which includes NP as oxygen carriers and oxygen-generating strategies to alleviate hypoxia monitored by PAI. The information obtained from quantitative tumor oxygenation by PAI not only supports optimal therapeutic design but also serves as a highly effective tool to predict therapeutic outcomes.

Industrialization's eye view on theranostic nanomedicine.

The emergence of nanomedicines (NMs) in the healthcare industry will bring about groundbreaking improvements to the current therapeutic and diagnostic scenario. However, only a few NMs have been developed into clinical applications due to a lack of regulatory experience with them. In this article, we introduce the types of NM that have the potential for clinical translation, including theranostics, multistep NMs, multitherapy NMs, and nanoclusters. We then present the clinical translational challenges associated with NM from the pharmaceutical industry's perspective, such as NMs' intrinsic physiochemical properties, safety, scale-up, lack of regulatory experience and standard characterization methods, and cost-effectiveness compared with their traditional counterparts. Overall, NMs face a difficult task to overcome these challenges for their transition from bench to clinical use.

Multimodal Magnetic Resonance and Photoacoustic Imaging of Tumor-Specific Enzyme-Responsive Hybrid Nanoparticles for Oxygen Modulation.

Multimodal imaging contrast agents for cancer that can not only perform diagnostic functions but also serve as tumor microenvironment-responsive biomaterials are encouraging. In this study, we report the design and fabrication of a novel enzyme-responsive T1 magnetic resonance imaging (MRI) contrast agent that can modulate oxygen in the tumor microenvironment via the catalytic conversion of H2O2 to O2. The T1 contrast agent is a core-shell nanoparticle that consists of manganese oxide and hyaluronic acid (HA)-conjugated mesoporous silica nanoparticle (HA-MnO@MSN). The salient features of the nanoparticle developed in this study are as follows: 1) HA serves as a targeting ligand for CD44-expressing cancer cells; 2) HA allows controlled access of water molecules to the MnO core via the digestion of enzyme hyaluronidase; 3) the generation of O2 bubbles in the tumor by consuming H2O2; and 4) the capability to increase the oxygen tension in the tumor. The r 1 relaxivity of HA-MnO@MSN was measured to be 1.29 mM-1s-1 at a magnetic field strength of 9.4 T. In vitro results demonstrated the ability of continuous oxygen evolution by HA-MnO@MSN. After intratumoral administration of HA-MnO@MSN to an HCT116 xenograft mouse model, T1 weighted MRI contrast was observed after 5 h postinjection and retained up to 48 h. In addition, in vivo photoacoustic imaging of HA-MnO@MSN demonstrated an increase in the tumor oxygen saturation over time after i. t. administration. Thus, the core-shell nanoparticles developed in this study could be helpful in tumor-targeted T1 MR imaging and oxygen modulation.

Probing the binding kinetics of proinflammatory cytokine-antibody interactions using dual color fluorescence cross correlation spectroscopy.

Dual color fluorescence cross correlation spectroscopy (FCCS) was used to investigate quantitatively the binding kinetics of tumor necrosis factor (TNFα) with TNFα antibody (anti-TNFα) following fluorescent labeling. Through the analysis of the auto correlation curves of fluorescence correlation spectroscopy (FCS), diffusion coefficients of 100.06 ± 4.9 µm(2) s(-1) and 48.96 ± 2.52 µm(2) s(-1) for Alexa488-TNFα and Atto647N-anti-TNFα were obtained. In addition, the calculated hydrodynamic diameters of the Alexa488-TNFα and Atto647N-anti-TNFα were approximately 4.89 ± 0.24 nm and 9.99 ± 0.52 nm, respectively, which agrees with the values of 5.20 ± 1.23 nm and 9.28 ± 0.86 nm for the native TNFα and the anti-TNFα as determined from dynamic light scattering measurements. For the binding kinetics, association (k(on)) and dissociation (k(off)) rate constants were (1.13 ± 0.08) × 10(4) M(-1) s(-1) and (1.53 ± 0.19) × 10(-3) s(-1) while the corresponding dissociation constant (K(d)) at 25 °C was (1.36 ± 0.10) × 10(-7) M. We believe this is the first report on the binding kinetics for TNFα-antibody recognition in the homogeneous phase. Using this technology, we have shown that controlled experiments can be performed to gain insight into molecular mechanisms involved in the immune response.

The protease-mediated nucleus shuttles of subnanometer gold quantum dots for real-time monitoring of apoptotic cell death.

Subnanometer photoluminescent gold quantum dots (GQDs) are functionalized with a peptide moiety that contains both nuclear export signal (NES) and nuclear localization signal (NLS) sequences. By taking advantage of its small size and great photostability, the functionalized GQDs are used to mimic the actions of nucleus shuttle proteins, especially of those activated during cell apoptotic death, to work as protease-mediated cytoplasm-nucleus shuttles for dynamic monitoring of apoptosis. The resulting construct demonstrates activation of the nuclear pore complex (NPC) of cells, for bidirectional transport between nucleus and cytoplasm. A caspase-3 recognition sequence (DEVD), placed within the NLS/NES peptide, serves as a proteolytic site for activated caspase-3. Upon the induction of apoptosis, the activated caspase-3 cleaves the functional peptide on GQDs resulting in changes of subcellular distribution of GQDs. Such changes can be quantified as a function of time, by the ratios of GQDs photoluminescence in nucleus to that in cytoplasm. As such, the NES-linker-DEVD-linker-NLS peptide enables the GQDs to function as molecular probes for the real-time monitoring of cellular apoptosis.

Biodegradable Polymers for Gene-Delivery Applications.

Gene-based therapies have emerged as a new modality for combating a myriad of currently incurable diseases. However, the fragile nature of gene therapeutics has significantly hampered their biomedical applications. Correspondingly, the development of gene-delivery vectors is of critical importance for gene-based therapies. To date, a variety of gene-delivery vectors have been created and utilized for gene delivery. In general, they can be categorized into viral- and non-viral vectors. Due to safety issues associated with viral vectors, non-viral vectors have recently attracted much more research focus. Of these non-viral vectors, polymeric vectors, which have been preferred due to their low immunogenicity, ease of production, controlled chemical composition and high chemical versatility, have constituted an ideal alternative to viral vectors. In particular, biodegradable polymers, which possess advantageous biocompatibility and biosafety, have been considered to have great potential in clinical applications. In this context, the aim of this review is to introduce the recent development and progress of biodegradable polymers for gene delivery applications, especially for their chemical structure design, gene delivery capacity and additional biological functions. Accordingly, we first define and categorize biodegradable polymers, followed by describing their corresponding degradation mechanisms. Various types of biodegradable polymers resulting from natural and synthetic polymers will be introduced and their applications in gene delivery will be examined. Finally, a future perspective regarding the development of biodegradable polymer vectors will be given.