alphaVbeta3-targeted copper nanoparticles incorporating an Sn 2 lipase-labile fumagillin prodrug for photoacoustic neovascular imaging and treatment

Noninvasive Visualization of Sub-5 mm Orthotopic Hepatic Tumors by a Nanoprobe-Mediated Positive and Reverse Contrast-Balanced Imaging Strategy

Delineation of small malignant lesions and their vasculature enables early and accurate diagnosis of hepatocellular carcinoma (HCC). However, it remains challenging to identify these features simultaneously by noninvasive imaging technology. Reverse contrast imaging emerges as a powerful means to detect early-stage HCC by taking inspiration from the intrinsic liver phagocytosis toward exogenous agents to generate negative tumor-to-normal tissue signals. However, this mechanism conflicts with the signal-enhancing requirements for vasculature visualization. Here, we solve this conundrum by designing a positive and reverse contrast-balanced imaging strategy based on a multifunctional PEG-Ta₂O₅@CuS nanoprobe that combines advanced gemstone spectral computer tomography (GSCT) with photoacoustic (PA) imaging. The nanoprobe exhibits preferential accumulation in Kupffer cells and hepatocytes over tumor cells, and its spectral properties are well matched with GSCT, leading to the enhancement of reverse contrast signals that enable clear delineation of 2-4 mm orthotopic HCC lesions. Meanwhile, its strong PA imaging capability at the second near-infrared (NIR-II) window makes vascular evaluation accessible by monitoring the positive signal enhancement derived from the limited tumor accumulation of the nanoprobe. In addition, the nanoprobe enables NIR-II photohyperthermia for timely tumor ablation. Overall, this proposed strategy shows potential in early detection and theranostics of HCC for improved clinical outcomes.

Synthesis and characterisation of N-gene targeted NIR-II fluorescent probe for selective localisation of SARS-CoV-2

Tracking the viral progression of SARS-CoV-2 in COVID-19 infected body tissues is an emerging need of the current pandemic. Imaging at near infrared second biological window (NIR-II) offers striking benefits over the other technologies to explore deep-tissue information. Here we design, synthesise and characterise a molecular probe that selectively targets the N-gene of SARS-CoV-2. Highly specific antisense oligonucleotides (ASOs) were conjugated to lead sulfide quantum dots using a UV-triggered thiol-ene click chemistry for the recognition of viral RNA. Our ex vivo imaging studies demonstrated that the probe exhibits aggregation induced NIR-II emission only in presence of SARS-CoV-2 RNA which can be attributed to the efficient hybridisation of the ASOs with their target RNA strands.

Organelle-Targeted Photosensitizers for Precision Photodynamic Therapy

Subcellular organelles are the cornerstones of cells, and destroying them will cause cell dysfunction and even death. Therefore, realizing precise organelle targeting of photosensitizers (PSs) can help reduce PS dosage, minimize side effects, avoid drug resistance, and enhance therapeutic efficacy in photodynamic therapy (PDT). Organelle-targeted PSs provide a new paradigm for the construction of the next generation of PSs and may provide implementable strategies for future precision medicine. In this Review, the recent targeting strategies of different organelles and the corresponding design principles of molecular and nanostructured PSs are summarized and discussed. The current challenges and opportunities in organelle-targeted PDT are also presented.

Monotherapy and Combination Therapy Using Anti-Angiogenic Nanoagents to Fight Cancer

Anti-angiogenic therapy, targeting vascular endothelial cells (ECs) to prevent tumor growth, has been attracting increasing attention in recent years, beginning with bevacizumab (Avastin) through its Phase II/III clinical trials on solid tumors. However, these trials showed only modest clinical efficiency; moreover, anti-angiogenic therapy may induce acquired resistance to the drugs employed. Combining advanced drug delivery techniques (e.g., nanotechnology) or other therapeutic strategies (e.g., chemotherapy, radiotherapy, phototherapy, and immunotherapy) with anti-angiogenic therapy results in significantly synergistic effects and has opened a new horizon in fighting cancer. Herein, clinical difficulties in using traditional anti-angiogenic therapy are discussed. Then, several promising applications of anti-angiogenic nanoagents in monotherapies and combination therapies are highlighted. Finally, the challenges and perspectives of anti-angiogenic cancer therapy are summarized. A useful introduction to anti-angiogenic strategies, which may significantly improve therapeutic outcomes, is thus provided.

Simple Equations Pertaining to the Particle Number and Surface Area of Metallic, Polymeric, Lipidic and Vesicular Nanocarriers

Introduction: Bioactive encapsulation and drug delivery systems have already found their way to the market as efficient therapeutics to combat infections, viral diseases and different types of cancer. The fields of food fortification, nutraceutical supplementation and cosmeceuticals have also been getting the benefit of encapsulation technologies. Aim: Successful formulation of such therapeutic and nutraceutical compounds requires thorough analysis and assessment of certain characteristics including particle number and surface area without the need to employ sophisticated analytical techniques. Solution: Here we present simple mathematical formulas and equations used in the research and development of drug delivery and controlled release systems employed for bioactive encapsulation and targeting the sites of infection and cancer in vitro and in vivo. Systems covered in this entry include lipidic vesicles, polymeric capsules, metallic particles as well as surfactant- and tocopherol-based micro- and nanocarriers.

An unmet clinical need: The history of thrombus imaging

Robust thrombus imaging is an unresolved clinical unmet need dating back to the mid 1970s. While early molecular imaging approaches began with nuclear SPECT imaging, contrast agents for virtually all biomedical imaging modalities have been demonstrated in vivo with unique strengths and common weaknesses. Two primary molecular imaging targets have been pursued for thrombus imaging: platelets and fibrin. Some common issues noted over 40 years ago persist today. Acute thrombus is readily imaged with all probes and modalities, but aged thrombus remains a challenge. Similarly, anti-coagulation continues to interfere with and often negate thrombus imaging efficacy, but heparin is clinically required in patients suspected of pulmonary embolism, deep venous thrombosis or coronary ruptured plaque prior to confirmatory diagnostic studies have been executed and interpreted. These fundamental issues can be overcome, but an innovative departure from the prior approaches will be needed.

pH-responsive targeted gold nanoparticles for in vivo photoacoustic imaging of tumor microenvironments

The acidic microenvironment of tumor tissues has been proven to be a major characteristic for differentiation from normal tissues, thereby providing a desirable target for both disease diagnosis and functional imaging. We herein introduce a way to endow gold nanoparticles with aggregation behaviour induced by pH tuning. The nanoparticle surface was modified with two thiol conjugate molecules, which could smartly stabilize it at the pH of blood and normal tissues but induce aggregation in response to the acidic extracellular pH in tumor. The surface conjugate molecule composition effect was studied systematically, and at the optimal surface conjugate molecule composition, a pH-responsive active tumor-targeting c(RGDyk)-MHDA/LSC@AuNP nanoprobe was successfully obtained and showed a significantly enhanced contrast effect for both in vitro and in vivo photoacoustic (PA) imaging. Intravenous administration of our nanoprobe to U87MG tumor-bearing nude mice showed PA imaging contrasts almost 3-fold higher than those for the blocking group. Quantitative biodistribution data revealed that 9.7 μg g^-1 of nanoprobe accumulated in the U87MG tumor 4 h post-injection. These findings might provide an effective strategy for developing new classes of intelligent and biocompatible contrast agents with a high efficiency for PA imaging and PA imaging-guided cancer therapy.

Theranostic Nanodots with Aggregation-Induced Emission Characteristic for Targeted and Image-Guided Photodynamic Therapy of Hepatocellular Carcinoma

Photosensitizer (PS) serves as the central element of photodynamic therapy (PDT). The use of common nanoparticles (NPs) for PDT has typically been rendered less effective by the undesirable aggregation-caused quenching (ACQ) effect, resulting in quenched fluorescence and reduced reactive oxygen species (ROS) generation that diminish the imaging quality and PDT efficacy. To overcome the ACQ effect and to enhance the overall efficacy of PDT, herein, integrin ανβ3-targeted organic nanodots for image-guided PDT were designed and synthesized based on a red emissive aggregation-induced emission (AIE) PS. Methods: The TPETS nanodots were prepared by nano-precipitation method and further conjugated with thiolated cRGD (cRGD-SH) through a click reaction to yield the targeted TPETS nanodots (T-TPETS nanodots). Nanodots were characterized for encapsulation efficiency, conjugation rate, particle size, absorption and emission spectra and ROS production. The targeted fluorescence imaging and antitumor efficacy of T-TPETS nanodot were evaluated both in vitro and in vivo. The mechanism of cell apoptosis induced by T-TPETS nanodot mediated-PDT was explored. The biocompatibility and toxicity of the nanodots was examined using cytotoxicity test, hemolysis assay, blood biochemistry test and histological staining. Results: The obtained nanodots show bright red fluorescence and highly effective 1O2 generation in aggregate state. Both in vitro and in vivo experiments demonstrate that the nanodots exhibit excellent tumor-targeted imaging performance, which facilitates image-guided PDT for tumor ablation in a hepatocellular carcinoma model. Detailed analysis reveals that the nanodot-mediated PDT is able to induce time- and concentration-dependent cell death. The use of PDT at a high PDT intensity leads to direct cell necrosis, while cell apoptosis via the mitochondria-mediated pathway is achieved under low PDT intensity. Conclusion: Our results suggest that well-designed AIE nanodots are promising for image-guided PDT applications.

Synthesis of Chiral Carbo-Nanotweezers for Enantiospecific Recognition and DNA Duplex Winding in Cancer Cells

Targeting the DNA of tumor cells with small molecules may offer effective clinical strategies for transcriptional inhibition. We unveil synthesis and characterization of ∼20 nm chiral carbon nanoparticles for enantiospecific recognition of DNA. Our approach inculcates chirality in carbon nanoparticles by controlled tethering of minor groove binders, i.e., Tröger's base (TB). The chiral particles positively enriched the cellular nucleus in MCF-7 breast cancer cells, irrespective of the TB asymmetry tethered on the particle surface, but negatively induced chiral carbon nanoparticles exhibited improved efficiency at inhibiting cell growth. Further studies indicated that these chiral particles act as nanotweezers to perturb the genomic DNA and induce apoptosis cascade in cancer cells.

Copper-Catalyzed Syntheses of Pyrene-Pyrazole Pharmacophores and Structure Activity Studies for Tubulin Polymerization

Tubulin polymerization is critical in mitosis process, which regulates uncontrolled cell divisions. Here, we report a new class of pyrene-pyrazole pharmacophore (PPP) for targeting microtubules. Syntheses of seven pyrenyl-substituted pyrazoles with side-chain modification at N-1 and C-3 positions of the pyrazole ring were accomplished from alkenyl hydrazones via C-N dehydrogenative cross-coupling using copper catalyst under aerobic condition. Tubulin polymerization with PPPs was investigated using docking and biological tools to reveal that these ligands are capable of influencing microtubule polymerization and their interaction with α-, β-tubulin active binding sites, which are substituent specific. Furthermore, cytotoxicity response of these PPPs was tested on cancer cells of different origin, such as MCF-7, MDA-MB231, and C32, and also noncancerous normal cells, such as MCF-10A. All newly synthesized PPPs showed excellent anticancer activities. The anticancer activities and half-maximal inhibitory concentration (IC₅₀) values of all PPPs across different cancer cell lines (MCF-7, MDA-MB231, and C32) have been demonstrated. 1,3-Diphenyl-5-(pyren-1-yl)-1H-pyrazole was found to be best among all other PPPs in killing significant population of all of the cancerous cell with IC₅₀ values 1 ± 0.5, 0.5 ± 0.2, and 5.0 ± 2.0 μM in MCF-7, MDA-MB231, and C32 cells, respectively.

Fluorescence Detection of Bone Microcracks Using Monophosphonated Carbon Dots

Phosphonated compounds, in particular, bisanalogs are widely applied in clinical settings for the treatment of severe bone turnovers and recently as imaging probes when conjugated with organic fluorophores. Herein, we introduce a bone seeking luminescent probe that shows a high binding affinity toward bone minerals based on monophosphonated carbon dots (CDs). Spheroidal CDs tethered with PEG monophosphates are synthesized in a one-pot hydrothermal method and are physicochemically characterized, where the retention of phosphonates is confirmed by ¹³P NMR and X-ray photoelectron spectroscopy. Interestingly, the high abundance of multiple monodentate phosphonates exhibited strong binding to hydroxyapatite, the main bone mineral constituent. The remarkable optophysical properties of monophosphonated CDs were confirmed in an ex vivo model of the bovine cortical bone where the imaging feasibility of microcracks, which are calcium-rich regions, was demonstrated. The in vivo studies specified the potential application of monophosphonated CDs for imaging when injected intramuscularly. The biodigestible nature and cytocompatibility of the probe presented here obviate the demand for a secondary fluorophore, while offering a nanoscale strategy for bone targeting and can eventually be employed for potential bone therapy in the future.

Crystalline assembly of gold nanoclusters for mitochondria targeted cancer theranostics

Herein, we report the formation of a crystalline assembly of gold (Au) nanoclusters for cancer theranostics via active targeting of mitochondria.

Current Challenges of Cancer Anti-angiogenic Therapy and the Promise of Nanotherapeutics

With growing interest in cancer therapeutics, anti-angiogenic therapy has received considerable attention and is widely administered in several types of human cancers. Nonetheless, this type of therapy may induce multiple signaling pathways compared with cytotoxics and lead to worse outcomes in terms of resistance, invasion, metastasis, and overall survival (OS). Moreover, there are important challenges that limit the translation of promising biomarkers into clinical practice to monitor the efficiency of anti-angiogenic therapy. These pitfalls emphasize the urgent need for discovering alternative angiogenic inhibitors that target multiple angiogenic factors or developing a new drug delivery system for the current inhibitors. The great advantages of nanoparticles are their ability to offer effective routes that target the biological system and regulate different vital processes based on their unique features. Limited studies so far have addressed the effectiveness of nanoparticles in the normalization of the delicate balance between stimulating (pro-angiogenic) and inhibiting (anti-angiogenic) factors. In this review, we shed light on tumor vessels and their microenvironment and consider the current directions of anti-angiogenic and nanotherapeutic treatments. To the best of our knowledge, we consider an important effort in the understanding of anti-angiogenic agents (often a small volume of metals, nonmetallic molecules, or polymers) that can control the growth of new vessels.

131I-Labeled Copper Sulfide-Loaded Microspheres to Treat Hepatic Tumors via Hepatic Artery Embolization

Purpose: Transcatheter hepatic artery embolization therapy is a minimally invasive alternative for treating inoperable liver cancer but recurrence is frequent. Multifunctional agents, however, offer an opportunity for tumor eradication. In this study, we were aim to synthesized poly (lactic-co-glycolic acid) (PLGA) microspheres encapsulating hollow CuS nanoparticles (HCuSNPs) and paclitaxel (PTX) that were then labeled with radioiodine-131 (¹³¹I) to produce ¹³¹I-HCuSNPs-MS-PTX. This compound combines the multi-theranostic properties of chemotherapy, radiotherapy and photothermal therapy. In addition, it can also be imaged with single photon emission computed tomography (SPECT) imaging and photoacoustic imaging. Methods: We investigated the value of therapeutic and imaging of ¹³¹I-HCuSNPs-MS-PTX in rats bearing Walker-256 tumor transplanted in the liver. After the intra-arterial (IA) injection of ¹³¹I-HCuSNPs-MS-PTX, ¹⁸F-Fluorodeoxyglucose (¹⁸F-FDG) micro-positron emission tomography/computed tomography (micro-PET/CT) imaging was used to monitor the therapeutic effect. PET/CT findings were verified by immunohistochemical analysis. SPECT/CT and photoacoustic imaging were performed to demonstrate the distribution of ¹³¹I-HCuSNPs-MS-PTX in vivo. Results: We found that embolization therapy in combination with chemotherapy, radiotherapy and photothermal therapy offered by ¹³¹I-HCuSNPs-MS-PTX completely ablated the transplanted hepatic tumors at a relatively low dose. In comparison, embolization monotherapy or combination with one or two other therapies had less effective anti-tumor efficacy. The combination of SPECT/CT and photoacoustic imaging effectively confirmed microsphere delivery to the targeted tumors in vivo and guided the near-infrared laser irradiation. Conclusion: Our study suggests that there is a clinical theranostic potential for imaging-guided arterial embolization with ¹³¹I-HCuSNPs-MS-PTX for the treatment of liver tumors.

Anti-angiogenic Nanotherapy Inhibits Airway Remodeling and Hyper-responsiveness of Dust Mite Triggered Asthma in the Brown Norway Rat

Although angiogenesis is a hallmark feature of asthmatic inflammatory responses, therapeutic anti-angiogenesis interventions have received little attention. Objective: Assess the effectiveness of anti-angiogenic Sn2 lipase-labile prodrugs delivered via α_vβ₃-micellar nanotherapy to suppress microvascular expansion, bronchial remodeling, and airway hyper-responsiveness in Brown Norway rats exposed to serial house dust mite (HDM) inhalation challenges. Results: Anti-neovascular effectiveness of α_vβ₃-mixed micelles incorporating docetaxel-prodrug (Dxtl-PD) or fumagillin-prodrug (Fum-PD) were shown to robustly suppress neovascular expansion (p<0.01) in the upper airways/bronchi of HDM rats using simultaneous ¹⁹F/¹H MR neovascular imaging, which was corroborated by adjunctive fluorescent microscopy. Micelles without a drug payload (α_vβ₃-No-Drug) served as a carrier-only control. Morphometric measurements of HDM rat airway size (perimeter) and vessel number at 21d revealed classic vascular expansion in control rats but less vascularity (p<0.001) after the anti-angiogenic nanotherapies. CD31 RNA expression independently corroborated the decrease in airway microvasculature. Methacholine (MCh) induced respiratory system resistance (Rrs) was high in the HDM rats receiving α_vβ₃-No-Drug micelles while α_vβ₃-Dxtl-PD or α_vβ₃-Fum-PD micelles markedly and equivalently attenuated airway hyper-responsiveness and improved airway compliance. Total inflammatory BAL cells among HDM challenged rats did not differ with treatment, but α_vβ₃⁺ macrophages/monocytes were significantly reduced by both nanotherapies (p<0.001), most notably by the α_vβ₃-Dxtl-PD micelles. Additionally, α_vβ₃-Dxtl-PD decreased BAL eosinophil and α_vβ₃⁺ CD45⁺ leukocytes relative to α_vβ₃-No-Drug micelles, whereas α_vβ₃-Fum-PD micelles did not. Conclusion: These results demonstrate the potential of targeted anti-angiogenesis nanotherapy to ameliorate the inflammatory hallmarks of asthma in a clinically relevant rodent model.

Water Soluble Melanin Derivatives for Dynamic Contrast Enhanced Photoacoustic Imaging of Tumor Vasculature and Response to Antiangiogenic Therapy

A dynamic contrast enhanced (DCE) approach for tumor photoacoustic (PA) imaging is described. Novel water soluble melanin-based derivatives are synthesized that exhibit good PA properties, stability, safety and accumulation in tumor bearing mice. This melanin derivative is capable to characterize tumor vasculature and to monitor vessel permeability changes upon antiangiogenic treatment. DCE-PA imaging can assess functional response to cancer treatments.

qFlow Cytometry-Based Receptoromic Screening: A High-Throughput Quantification Approach Informing Biomarker Selection and Nanosensor Development

Nanosensor-based detection of biomarkers can improve medical diagnosis; however, a critical factor in nanosensor development is deciding which biomarker to target, as most diseases present several biomarkers. Biomarker-targeting decisions can be informed via an understanding of biomarker expression. Currently, immunohistochemistry (IHC) is the accepted standard for profiling biomarker expression. While IHC provides a relative mapping of biomarker expression, it does not provide cell-by-cell readouts of biomarker expression or absolute biomarker quantification. Flow cytometry overcomes both these IHC challenges by offering biomarker expression on a cell-by-cell basis, and when combined with calibration standards, providing quantitation of biomarker concentrations: this is known as qFlow cytometry. Here, we outline the key components for applying qFlow cytometry to detect biomarkers within the angiogenic vascular endothelial growth factor receptor family. The key aspects of the qFlow cytometry methodology include: antibody specificity testing, immunofluorescent cell labeling, saturation analysis, fluorescent microsphere calibration, and quantitative analysis of both ensemble and cell-by-cell data. Together, these methods enable high-throughput quantification of biomarker expression.

Green synthesis of silver nanoparticles via plant extracts: beginning a new era in cancer theranostics

With the development of the latest technologies, scientists are looking to design novel strategies for the treatment and diagnosis of cancer. Advances in medicinal plant research and nanotechnology have attracted many researchers to the green synthesis of metallic nanoparticles due to its several advantages over conventional synthesis (simple, fast, energy efficient, one pot processes, safer, economical and biocompatibility). Medicinally active plants have proven to be the best reservoirs of diverse phytochemicals for the synthesis of biogenic silver nanoparticles (AgNPs). In this review, we discuss mechanistic advances in the synthesis and optimization of AgNPs from plant extracts. Moreover, we have thoroughly discussed the recent developments and milestones achieved in the use of biogenic AgNPs as cancer theranostic agents and their proposed mechanism of action. Anticipating all of the challenges, we hope that biogenic AgNPs may become a potential cancer theranostic agent in the near future.

Nano-Cesium for Anti-Cancer Properties: An Investigation into Cesium Induced Metabolic Interference

The use of cesium chloride (CsCl) for cancer therapy ("high pH therapy") has been theorized to produce anticancer properties by raising intracellular pH to induce apoptosis. Although considered as "alternative medicine", little scientific evidence supports this theory. Alternatively, cells have no cesium ion (Cs⁺) mediated channels for clearance. Thus, such unstable electrochemical distributions have the severe potential to disrupt electrochemical dependent cellular processes, such as glucose cotransporters. Hence, a detailed investigation of pH changing effects and glucose uptake inhibition are warranted as a possible cesium-induced anticancer therapy. We developed and characterized cesium nanoparticles (38 ± 6 nm), termed NanoCs, for nanoparticle-mediated internalization of the ion, and compared its treatment to free CsCl. Our investigations suggest that neither NanoCs nor CsCl drastically changed the intracellular pH, negating the theory. Alternatively, NanoCs lead to a significant decrease in glucose uptake when compared to free CsCl, suggesting cesium inhibited glucose uptake. An apoptosis assay of observed cell death affirms that NanoCs leads tumor cells to initiate apoptosis rather than follow necrotic behavior. Furthermore, NanoCs lead to in vivo tumor regression, where H&E analysis confirmed apoptotic cell populations. Thus, NanoCs performed pH-independent anticancer therapy by inducing metabolic stasis.

Plaque angiogenesis and its relation to inflammation and atherosclerotic plaque destabilization

PURPOSE OF REVIEW

The review discusses the recent literature on plaque angiogenesis and its relation to inflammation and plaque destabilization. Furthermore, it discusses how plaque angiogenesis can be used to monitor atherosclerosis and serve as a therapeutic target.

RECENT FINDINGS

Histopathologic studies have shown a clear relationship between plaque angiogenesis, intraplaque hemorrhage (IPH), plaque vulnerability, and cardiovascular events. Hypoxia is a main driver of plaque angiogenesis and the mechanism behind angiogenesis is only partly known. IPH, as the result of immature neovessels, is associated with increased influx of inflammatory cells in the plaques. Experimental models displaying certain features of human atherosclerosis such as plaque angiogenesis or IPH are developed and can contribute to unraveling the mechanism behind plaque vulnerability. New imaging techniques are established, with which plaque angiogenesis and vulnerability can be detected. Furthermore, antiangiogenic therapies in atherosclerosis gain much attention.

SUMMARY

Plaque angiogenesis, IPH, and inflammation contribute to plaque vulnerability. Histopathologic and imaging studies together with specific experimental studies have provided insights in plaque angiogenesis and plaque vulnerability. However, more extensive knowledge on the underlying mechanism is required for establishing new therapies for patients at risk.

Therapeutic application of anti-angiogenic nanomaterials in cancers

Angiogenesis, the formation of new blood vessels from pre-existing vasculature, plays a vital role in physiological and pathological processes (embryonic development, wound healing, tumor growth and metastasis). The overall balance of angiogenesis inside the human body is maintained by pro- and anti-angiogenic signals. The processes by which drugs inhibit angiogenesis as well as tumor growth are called the anti-angiogenesis technique, a most promising cancer treatment strategy. Over the last couple of decades, scientists have been developing angiogenesis inhibitors for the treatment of cancers. However, conventional anti-angiogenic therapy has several limitations including drug resistance that can create problems for a successful therapeutic strategy. Therefore, a new comprehensive treatment strategy using antiangiogenic agents for the treatment of cancer is urgently needed. Recently researchers have been developing and designing several nanoparticles that show anti-angiogenic properties. These nanomedicines could be useful as an alternative strategy for the treatment of various cancers using anti-angiogenic therapy. In this review article, we critically focus on the potential application of anti-angiogenic nanomaterial and nanoparticle based drug/siRNA/peptide delivery systems in cancer therapeutics. We also discuss the basic and clinical perspectives of anti-angiogenesis therapy, highlighting its importance in tumor angiogenesis, current status and future prospects and challenges.

Advancement in integrin facilitated drug delivery

The research of integrin-targeted anticancer agents has recorded important advancements in ingenious design of delivery systems, based either on the prodrug approach, or on nanoparticle carriers, but for now, none of these has reached a clinical stage of development. Past work in this area has been extensively reviewed by us and others. Thus, the purpose and scope of the present review is to survey the advancement reported in the last 3years, with focus on innovative delivery systems that appear to afford openings for future developments. These systems exploit the labelling with conventional and novel integrin ligands for targeting the interface of cancer cells and of endothelial cells involved in cancer angiogenesis, with the proteins of the extracellular matrix, in the circulation, in tissues, and in tumour stroma, as the site of progression and metastatic evolution of the disease. Furthermore, these systems implement the expertise in the development of nanomedicines to the purpose of achieving preferential biodistribution and uptake in cancer tissues, internalisation in cancer cells, and release of the transported drugs at intracellular sites. The assessment of the value of controlling these factors, and their combination, for future developments requires support of biological testing in appropriate mechanistic models, but also imperatively demand confirmation in therapeutically relevant in vivo models for biodistribution, efficacy, and lack of off-target effects. Thus, among many studies, we have tried to point out the results supported by relevant in vivo studies, and we have emphasised in specific sections those addressing the medical needs of drug delivery to brain tumours, as well as the delivery of oligonucleotides modulating gene-dependent pathological mechanism. The latter could constitute the basis of a promising third branch in the therapeutic armamentarium against cancer, in addition to antibody-based agents and to cytotoxic agents.

Dual-therapy with αvβ3-targeted Sn2 lipase-labile fumagillin-prodrug nanoparticles and zoledronic acid in the Vx2 rabbit tumor model

Fumagillin, an unstable anti-angiogenesis mycotoxin, was synthesized into a stable lipase-labile prodrug and incorporated into integrin-targeted lipid-encapsulated nanoparticles (αvβ3-Fum-PD NP). Dual anti-angiogenic therapy combining αvβ3-Fum-PD NP with zoledronic acid (ZA), a long-acting osteoclast inhibitor with proposed anti-angiogenic effects, was evaluated. In vitro, αvβ3-Fum-PD NP reduced (P<0.05) endothelial cell viability without impacting macrophage viability. ZA suppressed (P<0.05) macrophage viability at high dosages but not endothelial cell proliferation. 3D MR neovascular imaging of rabbit Vx2 tumors showed no effect with ZA, whereas αvβ3-Fum-PD NP alone and with ZA decreased angiogenesis (P<0.05). Immunohistochemistry revealed decreased (P<0.05) microvascularity with αvβ3-Fum-PD NP and ZA and further microvascular reduction (P<0.05) with dual-therapy. In vivo, ZA did not decrease tumor macrophage numbers nor cancer cell proliferation, whereas αvβ3-Fum-PD-NPs reduced both measures. Dual-therapy with ZA and αvβ3-Fum-PD-NP may provide enhanced neo-adjuvant utility if macrophage ZA uptake is increased. From the Clinical Editor: Although anti-angiogenesis is one of the treatment modalities in the fight against cancer, many cancers become resistant to VEGF pathway inhibitors. In this article, the authors investigated the use of dual therapy using fumagillin, integrin-targeted lipid-encapsulated nanoparticles (αvβ3- Fum-PD NP) and zoledronic acid (ZA), in both in-vitro and in-vivo experiments. This combination approach may provide an insight to the design of future drugs against cancers.

Contact-facilitated drug delivery with Sn2 lipase labile prodrugs optimize targeted lipid nanoparticle drug delivery

Sn2 lipase labile phospholipid prodrugs in conjunction with contact-facilitated drug delivery offer an important advancement in Nanomedicine. Many drugs incorporated into nanosystems, targeted or not, are substantially lost during circulation to the target. However, favorably altering the pharmacokinetics and volume of distribution of systemic drug delivery can offer greater efficacy with lower toxicity, leading to new prolonged-release nanoexcipients. However, the concept of achieving Paul Erhlich's inspired vision of a 'magic bullet' to treat disease has been largely unrealized due to unstable nanomedicines, nanosystems achieving low drug delivery to target cells, poor intracellular bioavailability of endocytosed nanoparticle payloads, and the substantial biological barriers of extravascular particle penetration into pathological sites. As shown here, Sn2 phospholipid prodrugs in conjunction with contact-facilitated drug delivery prevent premature drug diffusional loss during circulation and increase target cell bioavailability. The Sn2 phospholipid prodrug approach applies equally well for vascular constrained lipid-encapsulated particles and micelles the size of proteins that penetrate through naturally fenestrated endothelium in the bone marrow or thin-walled venules of an inflamed microcirculation. At one time Nanomedicine was considered a 'Grail Quest' by its loyal opposition and even many in the field adsorbing the pains of a long-learning curve about human biology and particles. However, Nanomedicine with innovations like Sn2 phospholipid prodrugs has finally made 'made the turn' toward meaningful translational success.

Lymphatic imaging: focus on imaging probes

In view of the importance of sentinel lymph nodes (SLNs) in tumor staging and patient management, sensitive and accurate imaging of SLNs has been intensively explored. Along with the advance of the imaging technology, various contrast agents have been developed for lymphatic imaging. In this review, the lymph node imaging agents were summarized into three groups: tumor targeting agents, lymphatic targeting agents and lymphatic mapping agents. Tumor targeting agents are used to detect metastatic tumor tissue within LNs, lymphatic targeting agents aim to visualize lymphatic vessels and lymphangionesis, while lymphatic mapping agents are mainly for SLN detection during surgery after local administration. Coupled with various signal emitters, these imaging agents work with single or multiple imaging modalities to provide a valuable way to evaluate the location and metastatic status of SLNs.