Tumor heterogeneity and its implication for drug delivery

Challenges and material innovations in drug delivery to central nervous system tumors

Central nervous system (CNS) tumors, encompassing a diverse array of neoplasms in the brain and spinal cord, pose significant therapeutic challenges due to their intricate anatomy and the protective presence of the blood-brain barrier (BBB). The primary treatment obstacle is the effective delivery of therapeutics to the tumor site, which is hindered by multiple physiological, biological, and technical barriers, including the BBB. This comprehensive review highlights recent advancements in material science and nanotechnology aimed at surmounting these delivery challenges, with a focus on the development and application of nanomaterials. Nanomaterials emerge as potent tools in designing innovative drug delivery systems that demonstrate the potential to overcome the limitations posed by CNS tumors. The review delves into various strategies, including the use of lipid nanoparticles, polymeric nanoparticles, and inorganic nanoparticles, all of which are engineered to enhance drug stability, BBB penetration, and targeted tumor delivery. Additionally, this review highlights the burgeoning role of theranostic nanoparticles, integrating therapeutic and diagnostic functionalities to optimize treatment efficacy. The exploration extends to biocompatible materials like biodegradable polymers, liposomes, and advanced material-integrated delivery systems such as implantable drug-eluting devices and microfabricated devices. Despite promising preclinical results, the translation of these material-based strategies into clinical practice necessitates further research and optimization.

Harnessing nanoparticles and bioorthogonal chemistries for improving precision of nuclear medicine

The convergence of nanotechnology, radiopharmaceutical development and molecular imaging has unveiled exciting opportunities for the progress of innovative diagnostic and therapeutic strategies, paving the way for significant advancements in biomedical research, especially in relation to cancer. For example, the use of highly sensitive and quantitative nuclear imaging techniques including PET and SPECT, together with nanoparticles for tumour imaging and therapy has recently expanded rapidly. While the long circulating properties of many nanomaterials are beneficial for prodrug chemotherapy formulations, due to the constant decay processes involved in nuclear medicines, directly labelled materials result in prolonged systemic radiation exposure and reduced therapeutic indices due to the unfavourable target-to-background ratios. This is due to the tendency for long circulating nanomaterials to distribute within the blood to other organs, such as the liver and spleen. The recent integration of bioorthogonal chemistry with nanotechnology and molecular imaging/radiotherapy has revolutionized the field by allowing the decoupling of the targeting molecule (i.e. nanomaterial with a bioorthogonal tag) and the imaging/therapeutic radioisotope. In this way, the detection/therapeutic element can be administered as a secondary "chase" molecule that contains the bioorthogonal partner, thereby creating an avenue to improve therapeutic index and provide imaging and treatments with reduced risk. This review will provide an overview of the progress made thus far in the field of nuclear imaging and radiotherapy for cancer using the combination of nanomaterials and bioorthogonal chemistry. We also provide a critical evaluation of the challenges and opportunities for using these approaches to better understand disease and treatment mechanisms, with the potential for downstream clinical translation.

Intratumoral heterogeneity and drug resistance in cancer

Intratumoral heterogeneity is the main cause of tumor treatment failure, varying across disease sites (spatial heterogeneity) and polyclonal properties of tumors that evolve over time (temporal heterogeneity). As our understanding of intratumoral heterogeneity, the formation of which is mainly related to the genomic instability, epigenetic modifications, plastic gene expression, and different microenvironments, plays a substantial role in drug-resistant as far as tumor metastasis and recurrence. Understanding the role of intratumoral heterogeneity, it becomes clear that a single therapeutic agent or regimen may only be effective for subsets of cells with certain features, but not for others. This necessitates a shift from our current, unchanging treatment approach to one that is tailored against the killing patterns of cancer cells in different clones. In this review, we discuss recent evidence concerning global perturbations of intratumoral heterogeneity, associations of specific intratumoral heterogeneity in lung cancer, the underlying mechanisms of intratumoral heterogeneity potentially leading to formation, and how it drives drug resistance. Our findings highlight the most up-to-date progress in intratumoral heterogeneity and its role in mediating tumor drug resistance, which could support the development of future treatment strategies.

Innovative cancer therapy: Unleashing the potential of macromolecule-loaded mesoporous bioactive glasses for precision diagnosis and treatment

Cancer continues to pose a formidable threat, claiming millions of lives annually. A beacon of hope in this battle lies in the realm of bioactive glasses, which have undergone a remarkable evolution over the past five decades. Among these, mesoporous bioactive glasses (MBGs) emerge as a dynamic subset endowed with customizable attributes such as high surface area and porosity. While holding immense promise for cancer care, the full clinical potential of MBGs remains largely unexplored. This review delves into the cutting-edge advancements in MBG technology, illuminating their pivotal role in cancer management - spanning from early detection to targeted therapeutic interventions like photothermal and photodynamic treatments. Furthermore, the molecular mechanisms underpinning MBGs' anticancer properties are elucidated, alongside an exploration of existing limitations in their application. Through this comprehensive synthesis, the significance of MBGs in revolutionizing cancer therapy is underscored, underscoring the urgent need for continued research to unlock their full potential in reshaping the landscape of cancer care.

Anticancer potential of phytochemicals derived from mangrove plants: Comprehensive mechanistic insights

Cancer is a collection of illnesses characterized by aberrant cellular proliferation that can infiltrate or metastasize to distant anatomical sites, posing a notable threat to human well-being due to its substantial morbidity and death rates worldwide. The potential of plant-derived natural compounds as anticancer medicines has been assessed owing to their favorable attributes of few side effects and significant antitumor activity. Mangrove plants and their derived compounds have been scientifically shown to exhibit many significant beneficial biological activities, such as anti-inflammatory, immunomodulatory, antioxidant, neuroprotective, cardioprotective, and hepatoprotective properties. This study summarized mangrove plants and their derived compounds as potential anticancer agents, with an emphasis on the underlying molecular mechanisms. To explore this, we gathered data on the preclinical (in vivo and in vitro) anticancer effects of mangrove plants and their derived compounds from reputable literature spanning 2000 to 2023. We conducted thorough searches in various academic databases, including PubMed, ScienceDirect, Wiley Online, SpringerLink, Google Scholar, Scopus, and the Web of Science. The results demonstrated that mangrove plants and their derived compounds have promising anticancer properties in preclinical pharmacological test systems through various molecular mechanisms, including induction of oxidative stress and mitochondrial dysfunction, cytotoxicity, genotoxicity, cell cycle arrest, apoptosis, autophagy, antiproliferative, antimetastatic, and other miscellaneous actions. Upon thorough observation of the pertinent information, it is suggested that mangrove plants and their derived chemicals may serve as a potential lead in the development of novel drugs for cancer therapy.

Relatively Rare Populations of Invasive Cells Drive Progression of Heterogeneous Tumors

Introduction

Breast tumors often display an astonishing degree of spatial and temporal heterogeneity, which are associated with cancer progression, drug resistance, and relapse. Triple-negative breast cancer (TNBC) is a particularly aggressive and heterogeneous subtype for which targeted therapies are scarce. Consequently, patients with TNBC have a poorer overall prognosis compared to other breast cancer patients. Within heterogeneous tumors, individual clonal subpopulations may exhibit differences in their rates of growth and degrees of invasiveness. We hypothesized that such phenotypic heterogeneity at the single-cell level may accelerate tumor progression by enhancing the overall growth and invasion of the entire tumor.

Methods

To test this hypothesis, we isolated and characterized clonal subpopulations with distinct morphologies and biomarker expression from the inherently heterogeneous 4T1 mouse mammary carcinoma cell line. We then leveraged a 3D microfluidic tumor model to reverse-engineer intratumoral heterogeneity and thus investigate how interactions between phenotypically distinct subpopulations affect tumor growth and invasion.

Results

We found that the growth and invasion of multiclonal tumors were largely dictated by the presence of cells with epithelial and mesenchymal traits, respectively. The latter accelerated overall tumor invasion, even when these cells comprised less than 1% of the initial population. Consistently, tumor progression was delayed by selectively targeting the mesenchymal subpopulation.

Discussion

This work reveals that highly invasive cells can dominate tumor phenotype and that specifically targeting these cells can slow the progression of heterogeneous tumors, which may help inform therapeutic approaches.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12195-023-00792-w.

Design of pH-responsive antimicrobial peptide melittin analog-camptothecin conjugates for tumor therapy

Melittin, a classical antimicrobial peptide, is a highly potent antitumor agent. However, its significant toxicity seriously hampers its application in tumor therapy. In this study, we developed novel melittin analogs with pH-responsive, cell-penetrating and membrane-lytic activities by replacing arginine and lysine with histidine. After conjugation with camptothecin (CPT), CPT-AAM-1 and CPT-AAM-2 were capable of killing tumor cells by releasing CPT at low concentrations and disrupting cell membranes at high concentrations under acidic conditions. Notably, we found that the C-terminus of the melittin analogs was more suitable for drug conjugation than the N-terminus. CPT-AAM-1 significantly suppressed melanoma growth in vivo with relatively low toxicity. Collectively, the present study demonstrates that the development of antitumor drugs based on pH-responsive antimicrobial peptide-drug conjugates is a promising strategy.

MRI-Based Interstitial Fluid Velocity Analysis for Drug Delivery Efficiency Evaluation in Tumor

There are many flow behaviors in solid tumors, including intravascular, bloodstream, and interstitial convection. Studies have shown that tumor interstitial fluid (TIF) is an important part of tumor microenvironment regulation and affects drug delivery and metabolism between tumor cells. Magnetic resonance imaging (MRI) is suitable for detecting the flow rates of liquids in tissues. Clinical phase contrast PC-MRI technology has been designed to observe the blood flow in large vessels such as arteries and veins; however, it is not sensitive enough to deal with slow flow velocity. Our previously developed vertical plane echo PC-MRI technology, the Velocity Mapping sequence, improved the signal-to-noise ratio (SNR) for measuring slow interstitial fluid rate. In this study, this sequence was used to determine the TIF flow rate in MDA-MB-231 human breast tumor cells used in BALB/c nude male mice. Two different sizes of contrast agents were intravenously injected, and the relationship between their distribution and the TIF flow rate was studied for the first time. Combining the results of clinical scanning showed that small-molecule DTPA-Gd (diethylenetriaminepentaacetic acid-gadolinium) was distributed immediately around the tumor margin after the injection. This distribution was positively correlated to the high flow rate area of the TIF before administration. In contrast, nanoparticles NaGdF4-PEG (polyethylene glycol) entered the tumor and reached their peak at 3 h. Drug distribution was negatively correlated with the high-flow-rate region of the TIF. Investigation of the TIF velocity can help better understand the fluid behavior in tumors and its role in drug delivery.

Patient-Derived Xenograft Models in Cancer Research: Methodology, Applications, and Future Prospects

Patient-derived xenografts (PDXs) have emerged as a pivotal tool in translational cancer research, addressing limitations of traditional methods and facilitating improved therapeutic interventions. These models involve engrafting human primary malignant cells or tissues into immunodeficient mice, allowing for the investigation of cancer mechanobiology, validation of therapeutic targets, and preclinical assessment of treatment strategies. This chapter provides an overview of PDXs methodology and their applications in both basic cancer research and preclinical studies. Despite current limitations, ongoing advancements in humanized xenochimeric models and autologous immune cell engraftment hold promise for enhancing PDX model accuracy and relevance. As PDX models continue to refine and extend their applications, they are poised to play a pivotal role in shaping the future of translational cancer research.

Addressing Genetic Tumor Heterogeneity, Post-Therapy Metastatic Spread, Cancer Repopulation, and Development of Acquired Tumor Cell Resistance

The concept of post-therapy metastatic spread, cancer repopulation and acquired tumor cell resistance (M-CRAC) rationalizes tumor progression because of tumor cell heterogeneity arising from post-therapy genetic damage and subsequent tissue repair mechanisms. Therapeutic strategies designed to specifically address M-CRAC involve tissue editing approaches, such as low-dose metronomic chemotherapy and the use of transcriptional modulators with or without targeted therapies. Notably, tumor tissue editing holds the potential to treat patients, who are refractory to or relapsing (r/r) after conventional chemotherapy, which is usually based on administering a maximum tolerable dose of a cytostatic drugs. Clinical trials enrolling patients with r/r malignancies, e.g., non-small cell lung cancer, Hodgkin's lymphoma, Langerhans cell histiocytosis and acute myelocytic leukemia, indicate that tissue editing approaches could yield tangible clinical benefit. In contrast to conventional chemotherapy or state-of-the-art precision medicine, tissue editing employs a multi-pronged approach targeting important drivers of M-CRAC across various tumor entities, thereby, simultaneously engaging tumor cell differentiation, immunomodulation, and inflammation control. In this review, we highlight the M-CRAC concept as a major factor in resistance to conventional cancer therapies and discusses tissue editing as a potential treatment.

Optomicrofluidic detection of cancer cells in peripheral blood via metabolic glycoengineering

The currently existing label-based techniques for the detection of circulating tumor cells (CTCs) target natural surface proteins of cells and are therefore applicable to only limited cancer cell types. We report optomicrofluidic detection of cancer cells in the pool of peripheral blood mononuclear cells (PBMCs) by exploiting the difference in their cell metabolism. We employ metabolic glycoengineering as a click chemistry tool for tagging cells that yields several fold-higher fluorescence signals from cancer cells compared to that from PBMCs. The effects of concentrations of the tagging compounds and cell incubation time on the fluorescence signal intensity are studied. The tagged cells were encapsulated in droplets ensuring that cells enter the detection region two-dimensionally focused in single-file and optically detected with a high detection efficiency and low coefficient of variation of the signals. The metabolic tagging approach showed a significantly higher tagging efficiency and average fluorescence signal compared to the well-established and widely adopted anti-EpCAM-FITC-based tagging. We demonstrated the detection of three different cancer cell lines - EpCAM-negative cervical cancer cell, HeLa, weakly EpCAM positive, and triple-negative breast cancer cell, MDA-MB-231, and strongly EpCAM positive breast cancer cell, MCF7, highlighting that the proposed technique is independent of naturally occurring cell surface proteins and widely applicable. The metabolically tagged and optically detected cells were successfully recultured, proving the compatibility of the proposed technique with downstream assays. The proposed technique is then utilised for the detection of CTCs in metastatic cancer patients' blood. The current work provides a new strategy for detecting cancer cells in the blood that can find potential applications in both fundamental research and clinical studies involving CTCs as well as in single-cell sequencing.

Dual-sensitive and highly biocompatible O-carboxymethyl chitosan nanodroplets for prostate tumor ultrasonic imaging and treatment

Nanosized drug delivery systems have rapidly emerged as a promising approach to tumor therapy, which still have many challenges in clinical application. In this study, doxorubicin-loaded O-carboxymethyl chitosan/perfluorohexane nanodroplets (O-CS-DOX NDs) were synthesized and functionally tested as an effective drug delivery system in vitro and in vivo. O-CS-DOX NDs with small size (159.6 nm) and good doxorubicin encapsuling ability showed pH- and ultrasound-dependent drug release profile and satisfying ultrasound imaging performance. With high biocompatibility and biosafety, these nanodroplets could accumulate in the tumor sites and exhibit high efficiency in inhibiting tumor growth with ultrasound irradiation. These stable, safe and smart O-CS-DOX NDs showed promising potential as a smart dual-responsive bomb for tumor ultrasonic imaging and treatment.

Predicting head and neck cancer treatment outcomes with pre-treatment quantitative ultrasound texture features and optimising machine learning classifiers with texture-of-texture features

Aim

Cancer treatments with radiation present a challenging physical toll for patients, which can be justified by the potential reduction in cancerous tissue with treatment. However, there remain patients for whom treatments do not yield desired outcomes. Radiomics involves using biomedical images to determine imaging features which, when used in tandem with retrospective treatment outcomes, can train machine learning (ML) classifiers to create predictive models. In this study we investigated whether pre-treatment imaging features from index lymph node (LN) quantitative ultrasound (QUS) scans parametric maps of head & neck (H&N) cancer patients can provide predictive information about treatment outcomes.

Methods

72 H&N cancer patients with bulky metastatic LN involvement were recruited for study. Involved bulky neck nodes were scanned with ultrasound prior to the start of treatment for each patient. QUS parametric maps and related radiomics texture-based features were determined and used to train two ML classifiers (support vector machines (SVM) and k-nearest neighbour (k-NN)) for predictive modeling using retrospectively labelled binary treatment outcomes, as determined clinically 3-months after completion of treatment. Additionally, novel higher-order texture-of-texture (TOT) features were incorporated and evaluated in regards to improved predictive model performance.

Results

It was found that a 7-feature multivariable model of QUS texture features using a support vector machine (SVM) classifier demonstrated 81% sensitivity, 76% specificity, 79% accuracy, 86% precision and an area under the curve (AUC) of 0.82 in separating responding from non-responding patients. All performance metrics improved after implementation of TOT features to 85% sensitivity, 80% specificity, 83% accuracy, 89% precision and AUC of 0.85. Similar trends were found with k-NN classifier.

Conclusion

Binary H&N cancer treatment outcomes can be predicted with QUS texture features acquired from index LNs. Prediction efficacy improved by implementing TOT features following methodology outlined in this work.

Vasculature organotropism in drug delivery

Over the past decades, there has been an exponential increase in the development of preclinical and clinical nanodelivery systems, and recently, an accelerating demand to deliver RNA and protein-based therapeutics. Organ-specific vasculature provides a promising intermediary for site-specific delivery of nanoparticles and extracellular vesicles to interstitial cells. Endothelial cells express organ-specific surface marker repertoires that can be used for targeted delivery. This article highlights organ-specific vasculature properties, nanodelivery strategies that exploit vasculature organotropism, and overlooked challenges and opportunities in targeting and simultaneously overcoming the endothelial barrier. Impediments in the clinical translation of vasculature organotropism in drug delivery are also discussed.

Curbing Exosome Communications via Introducing Artificial Membrane Receptors for Metastatic Pancreatic Cancer Therapy

Tumor-derived exosomes (TDEs) carry various biomolecular cargos and play crucial roles in metastasis. TDEs migrate to distal organs for intercellular communication and induce the formation of pre-metastatic niches (PMNs) to support tumor implantation and proliferation. Precise interference in the bioprocess of TDEs is expected to be efficacious for suppressing tumor metastasis. However, targeting both TDEs and the primary tumor is challenging. Here, based on metabolic glycoengineering and bio-orthogonal click chemistry, a two-step delivery strategy is designed to overcome this. During the first step, the tetraacetylated N-azidoacetyl-d-mannosamine-loaded nanoparticle responds to the metabolic activity of tumor cells in the primary tumor, tagging both tumor cells and TDEs with azide groups; dibenzyl-cyclootyne-modified nanoparticles then can, as the second step, specifically react with tumor cells and TDEs through a bio-orthogonal click reaction. This strategy not only inhibits tumor growth in pancreatic cancer models but also curbs the communicative role of TDEs in inducing liver PMNs and metastasis by tracking and downregulating the exosomal macrophage migration inhibitory factor.

Orally Bioavailable 4-Phenoxy-quinoline Compound as a Potent Aurora Kinase B Relocation Blocker for Cancer Treatment

We investigated a novel 4-phenoxy-quinoline-based scaffold that mislocalizes the essential mitotic kinase, Aurora kinase B (AURKB). Here, we evaluated the impact of halogen substitutions (F, Cl, Br, and I) on this scaffold with respect to various drug parameters. Br-substituted LXY18 was found to be a potent and orally bioavailable disruptor of cell division, at sub-nanomolar concentrations. LXY18 prevents cytokinesis by blocking AURKB relocalization in mitosis and exhibits broad-spectrum antimitotic activity in vitro. With a favorable pharmacokinetic profile, it shows widespread tissue distribution including the blood-brain barrier penetrance and effective accumulation in tumor tissues. More importantly, it markedly suppresses tumor growth. The novel mode of action of LXY18 may eliminate some drawbacks of direct catalytic inhibition of Aurora kinases. Successful development of LXY18 as a clinical candidate for cancer treatment could enable a new, less toxic means of antimitotic attack that avoids drug resistance mechanisms.

Cancer-associated fibroblast-targeted nanodrugs reshape colorectal tumor microenvironments to suppress tumor proliferation, metastasis and improve drug penetration

Cancer-associated fibroblasts (CAFs) produce a critical tumor-promoting effect by cellular crosstalk with cancer cells and remodel the extracellular matrix (ECM) to form a protective physical barrier. The simple elimination of CAFs is not sufficient to govern the CAF-shaped aggressive tumor microenvironment (TME) because of the complexity of tumors. Herein, a CAF-targeted poly (lactic-co-glycolic acid) (PLGA) nanoemulsion is tailored to simultaneously deliver doxorubicin (DOX) and small interfering RNA (siRNA) targeting hepatocyte growth factor (HGF) for the combination of chemotherapy and gene therapy. The nanoemulsion (apt-Si/DNPs) shows a high specificity towards CAFs due to the aptamer modification and efficiently induces the apoptosis of CAFs, thus decreasing ECM deposition in the TME. Importantly, the delivered siRNA reduces the expression of the HGF in the remaining CAFs, which overcomes chemotherapy-induced upregulation of HGF mRNA and prevents the reproduction of CAFs through the autocrine HGF closed-loop. Owing to these synergetic effects, tumor proliferation, migration and invasion are prominently inhibited and tumor permeability is improved significantly. Overall, these results emphasize the potential of CAF-targeted combination treatments to inhibit tumor progression and metastasis, as well as overcome therapeutic resistance.

Design of a novel integrated microfluidic chip for continuous separation of circulating tumor cells from peripheral blood cells

Cancer is one of the foremost causes of death globally. Late-stage presentation, inaccessible diagnosis, and treatment are common challenges in developed countries. Detection, enumeration of Circulating Tumor Cells (CTC) as early as possible can reportedly lead to more effective treatment. The isolation of CTC at an early stage is challenging due to the low probability of its presence in peripheral blood. In this study, we propose a novel two-stage, label-free, rapid, and continuous CTC separation device based on hydrodynamic inertial focusing and dielectrophoretic separation. The dominance and differential of wall-induced inertial lift force and Dean drag force inside a curved microfluidic channel results in size-based separation of Red Blood Cells (RBC) and platelets (size between 2-4 µm) from CTC and leukocytes (9-12.2 µm). A numerical model was used to investigate the mechanism of hydrodynamic inertial focusing in a curvilinear microchannel. Simulations were done with the RBCs, platelets, CTCs, and leukocytes (four major subtypes) to select the optimized value of the parameters in the proposed design. In first stage, the focusing behavior of microscale cells was studied to sort leukocytes and CTCs from RBCs, and platelets while viable CTCs were separated from leukocytes based on their inherent electrical properties using dielectrophoresis in the second stage. The proposed design of the device was evaluated for CTC separation efficiency using numerical simulations. This study considered the influence of critical factors like aspect ratio, dielectrophoretic force, channel size, flow rate, separation efficiency, and shape on cell separation. Results show that the proposed device yields viable CTC with 99.5% isolation efficiency with a throughput of 12.2 ml/h.

Harnessing Rift Valley fever virus NSs gene for cancer gene therapy

One of the greatest challenges in the treatment of cancer is tumor heterogeneity which results in differential responses to chemotherapy and drugs that work through a single pathway. A therapeutic agent that targets cancer cells for death through multiple mechanisms could be advantageous as a broad inhibitor for many types of cancers and the heterogeneous alterations they possess. Several viral proteins have been exploited for antiproliferative and apoptotic effect in cancer cells by disrupting critical survival pathways. Here, we report the use of the non-structural protein on the S segment (NSs) gene from the Rift Valley fever virus (RVFV) to induce cancer cell death. NSs has immune evasion functions in the context of RVFV with many of these functions affecting proliferation pathways and DNA damage signaling, which could be leveraged against cancer cells. We find that expression of NSs in multiple cancer cell lines leads to a rapid decline in cell viability and induction of apoptosis. Interestingly, we observed reduced toxicity in normal cells suggesting cancer cells may be more susceptible to NSs-mediated cell death. To enhance specificity of NSs for use in hepatocellular carcinoma, we incorporated four miR-122 binding sites in the 3' untranslated region (UTR) of the NSs mRNA to achieve cell type specific expression. Observations presented here collectively suggest that delivery of the NSs gene may provide a unique therapeutic approach in a broad range of cancers.

Functional Nanoparticles for Enhanced Cancer Therapy

Cancer is the leading cause of death in people worldwide. The conventional therapeutic approach is mainly based on chemotherapy, which has a series of side effects. Compared with traditional chemotherapy drugs, nanoparticle-based delivery of anti-cancer drugs possesses a few attractive features. The application of nanotechnology in an interdisciplinary manner in the biomedical field has led to functional nanoparticles achieving much progress in cancer therapy. Nanoparticles have been involved in the diagnosis and targeted and personalized treatment of cancer. For example, different nano-drug strategies, including endogenous and exogenous stimuli-responsive, surface conjugation, and macromolecular encapsulation for nano-drug systems, have successfully prevented tumor procession. The future for functional nanoparticles is bright and promising due to the fast development of nanotechnology. However, there are still some challenges and limitations that need to be considered. Based on the above contents, the present article analyzes the progress in developing functional nanoparticles in cancer therapy. Research gaps and promising strategies for the clinical application are discussed.

Label-free sensing of cells with fluorescence lifetime imaging: The quest for metabolic heterogeneity

Molecular, morphological, and physiological heterogeneity is the inherent property of cells which governs differences in their response to external influence. Tumor cell metabolic heterogeneity is of a special interest due to its clinical relevance to tumor progression and therapeutic outcomes. Rapid, sensitive, and noninvasive assessment of metabolic heterogeneity of cells is a great demand for biomedical sciences. Fluorescence lifetime imaging (FLIM), which is an all-optical technique, is an emerging tool for sensing and quantifying cellular metabolism by measuring fluorescence decay parameters of endogenous fluorophores, such as NAD(P)H. To achieve accurate discrimination between metabolically diverse cellular subpopulations, appropriate approaches to FLIM data collection and analysis are needed. In this paper, the unique capability of FLIM to attain the overarching goal of discriminating metabolic heterogeneity is demonstrated. This has been achieved using an approach to data analysis based on the nonparametric analysis, which revealed a much better sensitivity to the presence of metabolically distinct subpopulations compared to more traditional approaches of FLIM measurements and analysis. The approach was further validated for imaging cultured cancer cells treated with chemotherapy. These results pave the way for accurate detection and quantification of cellular metabolic heterogeneity using FLIM, which will be valuable for assessing therapeutic vulnerabilities and predicting clinical outcomes.

Copper-Free Click Chemistry: Applications in Drug Delivery, Cell Tracking, and Tissue Engineering

Traditionally, organic chemical reactions require organic solvents, toxic catalysts, heat, or high pressure. However, copper-free click chemistry has been shown to have favorable reaction rates and orthogonality in water, buffer solutions, and physiological conditions without toxic catalysts. Strain-promoted azide-alkyne cycloaddition and inverse electron-demand Diels-Alder reactions are representative of copper-free click chemistry. Artificial chemical reactions via click chemistry can also be used outside of the laboratory in a controllable manner on live cell surfaces, in the cytosol, and in living bodies. Consequently, copper-free click chemistry has many features that are of interest in biomedical research, and various new materials and strategies for its use have been proposed. Herein, recent remarkable trials that have used copper-free click chemistry are described, focusing on their applications in molecular imaging and therapy. The research is categorized as nanoparticles for drug delivery, imaging agents for cell tracking, and hydrogels for tissue engineering, which are rapidly advancing fields based on click chemistry. The content is based primarily on the experience with click chemistry-based biomaterials over the last 10 years.

Metal-free bioorthogonal click chemistry in cancer theranostics

Bioorthogonal chemistry is a powerful tool to site-specifically activate drugs in living systems. Bioorthogonal reactions between a pair of biologically reactive groups can rapidly and specifically take place in a mild physiological milieu without perturbing inherent biochemical processes. Attributed to their high selectivity and efficiency, bioorthogonal reactions can significantly decrease background signals in bioimaging. Compared with metal-catalyzed bioorthogonal click reactions, metal-free click reactions are more biocompatible without the metal catalyst-induced cytotoxicity. Although a great number of bioorthogonal chemistry-based strategies have been reported for cancer theranostics, a comprehensive review is scarce to highlight the advantages of these strategies. In this review, recent progress in cancer theranostics guided by metal-free bioorthogonal click chemistry will be depicted in detail. The elaborate design as well as the advantages of bioorthogonal chemistry in tumor theranostics are summarized and future prospects in this emerging field are emphasized.

Analysis of the Single-Cell Heterogeneity of Adenocarcinoma Cell Lines and the Investigation of Intratumor Heterogeneity Reveals the Expression of Transmembrane Protein 45A (TMEM45A) in Lung Adenocarcinoma Cancer Patients

Simple Summary

Non-small cell lung cancer (NSCLC) is one of the main causes of cancer-related deaths worldwide. Intratumoral heterogeneity (ITH) is responsible for the majority of difficulties encountered in the treatment of lung-cancer patients. Therefore, the heterogeneity of NSCLC cell lines and primary lung adenocarcinoma was investigated by single-cell mass cytometry (CyTOF). Human NSCLC adenocarcinoma cells A549, H1975, and H1650 were studied at single-cell resolution for the expression pattern of 13 markers: GLUT1, MCT4, CA9, TMEM45A, CD66, CD274, CD24, CD326, pan-keratin, TRA-1-60, galectin-3, galectin-1, and EGFR. The intra- and inter-cell-line heterogeneity of A549, H1975, and H1650 cells were demonstrated through hypoxic modeling. Additionally, human primary lung adenocarcinoma, and non-involved healthy lung tissue were homogenized to prepare a single-cell suspension for CyTOF analysis. The single-cell heterogeneity was confirmed using unsupervised viSNE and FlowSOM analysis. Our results also show, for the first time, that TMEM45A is expressed in lung adenocarcinoma.

Abstract

Intratumoral heterogeneity (ITH) is responsible for the majority of difficulties encountered in the treatment of lung-cancer patients. Therefore, the heterogeneity of NSCLC cell lines and primary lung adenocarcinoma was investigated by single-cell mass cytometry (CyTOF). First, we studied the single-cell heterogeneity of frequent NSCLC adenocarcinoma models, such as A549, H1975, and H1650. The intra- and inter-cell-line single-cell heterogeneity is represented in the expression patterns of 13 markers—namely GLUT1, MCT4, CA9, TMEM45A, CD66, CD274 (PD-L1), CD24, CD326 (EpCAM), pan-keratin, TRA-1-60, galectin-3, galectin-1, and EGFR. The qRT-PCR and CyTOF analyses revealed that a hypoxic microenvironment and altered metabolism may influence cell-line heterogeneity. Additionally, human primary lung adenocarcinoma and non-involved healthy lung tissue biopsies were homogenized to prepare a single-cell suspension for CyTOF analysis. The CyTOF showed the ITH of human primary lung adenocarcinoma for 14 markers; particularly, the higher expressions of GLUT1, MCT4, CA9, TMEM45A, and CD66 were associated with the lung-tumor tissue. Our single-cell results are the first to demonstrate TMEM45A expression in human lung adenocarcinoma, which was verified by immunohistochemistry.

Evaluation of PD-L1 Expression Level in Patients With Non-Small Cell Lung Cancer by 18F-FDG PET/CT Radiomics and Clinicopathological Characteristics

PURPOSE

In the present study, we aimed to evaluate the expression of programmed death-ligand 1 (PD-L1) in patients with non-small cell lung cancer (NSCLC) by radiomic features of 18F-FDG PET/CT and clinicopathological characteristics.

METHODS

A total 255 NSCLC patients (training cohort: n = 170; validation cohort: n = 85) were retrospectively enrolled in the present study. A total of 80 radiomic features were extracted from pretreatment 18F-FDG PET/CT images. Clinicopathologic features were compared between the two cohorts. The least absolute shrinkage and selection operator (LASSO) regression was used to select the most useful prognostic features in the training cohort. Radiomics signature and clinicopathologic risk factors were incorporated to develop a prediction model by using multivariable logistic regression analysis. The receiver operating characteristic (ROC) curve was used to assess the prognostic factors.

RESULTS

A total of 80 radiomic features were extracted in the training dataset. In the univariate analysis, the expression of PD-L1 in lung tumors was significantly correlated with the radiomic signature, histologic type, Ki-67, SUVmax, MTV, and TLG (p< 0.05, respectively). However, the expression of PD-L1 was not correlated with age, TNM stage, and history of smoking (p> 0.05). Moreover, the prediction model for PD-L1 expression level over 1% and 50% that combined the radiomic signature and clinicopathologic features resulted in an area under the curve (AUC) of 0.762 and 0.814, respectively.

CONCLUSIONS

A prediction model based on PET/CT images and clinicopathological characteristics provided a novel strategy for clinicians to screen the NSCLC patients who could benefit from the anti-PD-L1 immunotherapy.

High-Specificity In Vivo Tumor Imaging Using Bioorthogonal NIR-IIb Nanoparticles

Lanthanide-based NIR-IIb nanoprobes are ideal for in vivo imaging. However, existing NIR-IIb nanoprobes often suffer from low tumor-targeting specificity, limiting their widespread use. Here the application of bioorthogonal nanoprobes with high tumor-targeting specificity for in vivo NIR-IIb luminescence imaging and magnetic resonance imaging (MRI) is reported. These dual-modality nanoprobes can enhance NIR-IIb emission by 20-fold and MRI signal by twofold, compared with non-bioorthogonal nanoprobes in murine subcutaneous tumors. Moreover, these bioorthogonal probes enable orthotopic brain tumor imaging. Implementation of bio-orthogonal chemistry significantly reduces the nanoprobe dose and hence cytotoxicity, providing a paradigm for real-time in vivo visualization of tumors.

A novel ultralow conductivity electromanipulation buffer improves cell viability and enhances dielectrophoretic consistency

Cell separation has become a critical diagnostic, research, and treatment tool for personalized medicine. Despite significant advances in cell separation, most widely used applications require the use of multiple, expensive antibodies to known markers in order to identify subpopulations of cells for separation. Dielectrophoresis (DEP) provides a biophysical separation technique that can target cell subpopulations based on phenotype without labels and return native cells for downstream analysis. One challenge in employing any DEP device is the sample being separated must be transferred into an ultralow conductivity medium, which can be detrimental in retaining cells' native phenotypes for separation. Here, we measured properties of traditional DEP reagents and determined that after just 1-2 h of exposure and subsequent culture, cells' viability was significantly reduced below 50%. We developed and tested a novel buffer (Cyto Buffer) that achieved 6 weeks of stable shelf-life and demonstrated significantly improved viability and physiological properties. We then determined the impact of Cyto Buffer on cells' dielectric properties and morphology and found that cells retained properties more similar to that of their native media. Finally, we vetted Cyto Buffer's usability on a cell separation platform (Cyto R1) to determine combined efficacy for cell separations. Here, more than 80% of cells from different cell lines were recovered and were determined to be >70% viable following exposure to Cyto Buffer, flow stimulation, electromanipulation, and downstream collection and growth. The developed buffer demonstrated improved opportunities for electrical cell manipulation, enrichment, and recovery for next generation cell separations.

Ratiometric Fluorescence Monitoring of Antibody-Guided Drug Delivery to Cancer Cells

Ratiometric measurements utilizing two independent fluorescence signals from a dual-dye molecular system help to improve the detection sensitivity and quantification of many analytical, bioanalytical, and pharmaceutical assays, including drug delivery monitoring. Nevertheless, these dual-dye conjugates have never been utilized for ratiometric monitoring of antibody (Ab)-guided targeted drug delivery (TDD). Here, we report for the first time on the new, dual-dye TDD system, Cy5s-Ab-Flu-Aza, comprising the switchable fluorescein-based dye (Flu) linked to the anticancer drug azatoxin (Aza), reference pentamethine cyanine dye (Cy5s), and Her2-specific humanized monoclonal Trastuzumab (Herceptin) antibody. The ability of ratiometric fluorescence monitoring of drug release was demonstrated with this model system in vitro in the example of the human breast cancer SKBR3 cell line overexpressing Her2 receptors. The proposed approach for designing ratiometric, antibody-guided TDD systems, where a "drug-switchable dye" conjugate and a reference dye are independently linked to an antibody, can be expanded to other drugs, dyes, and antibodies. Replacement of the green-emitting dye Flu, which was found not detectable in vivo, with a longer-wavelength (red or near-IR) switchable fluorophore should enable quantification of drug release in the body.

Dual-Targeting and Stimuli-Triggered Liposomal Drug Delivery in Cancer Treatment

The delivery of chemotherapeutics to solid tumors using smart drug delivery systems (SDDSs) takes advantage of the unique physiology of tumors (i.e., disordered structure, leaky vasculature, abnormal extracellular matrix (ECM), and limited lymphatic drainage) to deliver anticancer drugs with reduced systemic side effects. Liposomes are the most promising of such SDDSs and have been well investigated for cancer therapy. To improve the specificity, bioavailability, and anticancer efficacy of liposomes at the diseased sites, other strategies such as targeting ligands and stimulus-sensitive liposomes have been developed. This review highlights relevant surface functionalization techniques and stimuli-mediated drug release for enhanced delivery of anticancer agents at tumor sites, with a special focus on dual functionalization and design of multistimuli responsive liposomes.

Nanodelivery of natural isothiocyanates as a cancer therapeutic

Natural isothiocyanates (ITCs) are phytochemicals abundant in cruciferous vegetables with the general structure, R-NCS. They are bioactive organosulfur compounds derived from the hydrolysis of glucosinolates by myrosinase. A significant number of isothiocyanates have been isolated from different plant sources that include broccoli, Brussels sprouts, cabbage, cauliflower, kale, mustard, wasabi, and watercress. Several ITCs have been demonstrated to possess significant pharmacological properties including: antioxidant, anti-inflammatory, anti-cancer and antimicrobial activities. Due to their chemopreventive effects on many types of cancer, ITCs have been regarded as a promising anti-cancer therapeutic agent without major toxicity concerns. However, their clinical application has been hindered by several factors including their low aqueous solubility, low bioavailability, instability as well as their hormetic effect. Moreover, the typical dietary uptake of ITCs consumed for promotion of good health may be far from their bioactive (or cytotoxic) dose necessary for cancer prevention and/or treatment. Nanotechnology is one of best options to attain enhanced efficacy and minimize hormetic effect for ITCs. Nanoformulation of ITCs leads to enhance stability of ITCs in plasma and emphasize on their chemopreventive effects. This review provides a summary of the potential bioactivities of ITCs, their mechanisms of action for the prevention and treatment of cancer, as well as the recent research progress in their nanodelivery strategies to enhance solubility, bioavailability, and anti-cancer efficacy.

In-vitro tumor microenvironment models containing physical and biological barriers for modelling multidrug resistance mechanisms and multidrug delivery strategies

The complexity and heterogeneity of the three-dimensional (3D) tumor microenvironment have brought challenges to tumor studies and cancer treatment. The complex functions and interactions of cells involved in tumor microenvironment have led to various multidrug resistance (MDR) and raised challenges for cancer treatment. Traditional tumor models are limited in their ability to simulate the resistance mechanisms and not conducive to the discovery of multidrug resistance and delivery processes. New technologies for making 3D tissue models have shown the potential to simulate the 3D tumor microenvironment and identify mechanisms underlying the MDR. This review overviews the main barriers against multidrug delivery in the tumor microenvironment and highlights the advances in microfluidic-based tumor models with the success in simulating several drug delivery barriers. It also presents the progress in modeling various genetic and epigenetic factors involved in regulating the tumor microenvironment as a noticeable insight in 3D microfluidic tumor models for recognizing multidrug resistance and delivery mechanisms. Further correlation between the results obtained from microfluidic drug resistance tumor models and the clinical MDR data would open up avenues to gain insight into the performance of different multidrug delivery treatment strategies.

Bioorthogonal Pretargeting Strategy for Anchoring Activatable Photosensitizers on Plasma Membranes for Effective Photodynamic Therapy

Developing novel activatable photosensitizers with excellent plasma membrane targeting ability is urgently needed for smart photodynamic therapy (PDT). Herein, a tumor acidity-activatable photosensitizer combined with a two-step bioorthogonal pretargeting strategy to anchor photosensitizers on the plasma membrane for effective PDT is developed. Briefly, artificial receptors are first anchored on the cell plasma membrane using cell-labeling agents (Az-NPs) via the enhanced permeability and retention effect to achieve the tumor cell labeling. Then, pH-sensitive nanoparticles (S-NPs) modified with dibenzocyclooctyne (DBCO) and chlorin e6 (Ce6) accumulate in tumor tissue and disassemble upon protonation of their tertiary amines in response to the acidic tumor environment, exposing the contained DBCO and Ce6. The selective, highly specific click reactions between DBCO and azide groups enable Ce6 to be anchored on the tumor cell surface. Upon laser irradiation, the cell membrane is severely damaged by the cytotoxic reactive oxygen species, resulting in remarkable cellular apoptosis. Taken together, the membrane-localized PDT by our bioorthogonal pretargeting strategy to anchor activatable photosensitizers on the plasma membrane provides a simple but effective method for enhancing the therapeutic efficacy of photosensitizers in anticancer therapy.

Nanoparticles and bioorthogonal chemistry joining forces for improved biomedical applications

Bioorthogonal chemistry comprises chemical reactions that can take place inside complex biological environments, providing outstanding tools for the investigation and elucidation of biological processes. Its use in combination with nanotechnology can lead to further developments in diverse areas of biomedicine, such as molecular bioimaging, targeted delivery, in situ drug activation, study of cell-nanomaterial interactions, biosensing, etc. Here, we summarise the recent efforts to bring together the unique properties of nanoparticles and the remarkable features of bioorthogonal reactions to create a toolbox of new or improved biomedical applications. We show how, by joining forces, bioorthogonal chemistry and nanotechnology can overcome some of the key current limitations in the field of nanomedicine, providing better, faster and more sensitive nanoparticle-based bioimaging and biosensing techniques, as well as therapeutic nanoplatforms with superior efficacy.

Tumor-Targeting Glycol Chitosan Nanoparticles for Cancer Heterogeneity

Nanomedicine is extensively employed for cancer treatment owing to its unique advantages over conventional drugs and imaging agents. This increased attention to nanomedicine, however, has not fully translated into clinical utilization and patient benefits due to issues associated with reticuloendothelial system clearance, tumor heterogeneity, and complexity of the tumor microenvironment. To address these challenges, efforts are being made to modify the design of nanomedicines, including optimization of their physiochemical properties, active targeting, and response to stimuli, but these studies are often performed independently. Combining favorable nanomedicine designs from individual studies may improve therapeutic outcomes, but, this is difficult to achieve as the effects of different designs are interconnected and often conflicting. Glycol chitosan nanoparticles (CNPs) are shown to accumulate in tumors, suggesting that this type of nanoparticle may constitute a good basis for the additional modification of nanoparticles. Here, multifunctional glycol CNPs designed to overcome multiple obstacles to their use are described and key factors influencing in vivo targeted delivery, targeting strategies, and interesting stimulus-responsive designs for improving cancer nanomedicine are discussed.

A computational diffusion model to study antibody transport within reconstructed tumor microenvironments

Background

Antibodies revolutionized cancer treatment over the past decades. Despite their successfully application, there are still challenges to overcome to improve efficacy, such as the heterogeneous distribution of antibodies within tumors. Tumor microenvironment features, such as the distribution of tumor and other cell types and the composition of the extracellular matrix may work together to hinder antibodies from reaching the target tumor cells. To understand these interactions, we propose a framework combining in vitro and in silico models. We took advantage of in vitro cancer models previously developed by our group, consisting of tumor cells and fibroblasts co-cultured in 3D within alginate capsules, for reconstruction of tumor microenvironment features.

Results

In this work, an experimental-computational framework of antibody transport within alginate capsules was established, assuming a purely diffusive transport, combined with an exponential saturation effect that mimics the saturation of binding sites on the cell surface. Our tumor microenvironment in vitro models were challenged with a fluorescent antibody and its transport recorded using light sheet fluorescence microscopy. Diffusion and saturation parameters of the computational model were adjusted to reproduce the experimental antibody distribution, with root mean square error under 5%. This computational framework is flexible and can simulate different random distributions of tumor microenvironment elements (fibroblasts, cancer cells and collagen fibers) within the capsule. The random distribution algorithm can be tuned to follow the general patterns observed in the experimental models.

Conclusions

We present a computational and microscopy framework to track and simulate antibody transport within the tumor microenvironment that complements the previously established in vitro models platform. This framework paves the way to the development of a valuable tool to study the influence of different components of the tumor microenvironment on antibody transport.

Deep Tumor Penetration of Doxorubicin-Loaded Glycol Chitosan Nanoparticles Using High-Intensity Focused Ultrasound

The dense extracellular matrix (ECM) in heterogeneous tumor tissues can prevent the deep tumor penetration of drug-loaded nanoparticles, resulting in a limited therapeutic efficacy in cancer treatment. Herein, we suggest that the deep tumor penetration of doxorubicin (DOX)-loaded glycol chitosan nanoparticles (CNPs) can be improved using high-intensity focused ultrasound (HIFU) technology. Firstly, we prepared amphiphilic glycol chitosan-5β-cholanic acid conjugates that can self-assemble to form stable nanoparticles with an average of 283.7 ± 5.3 nm. Next, the anticancer drug DOX was simply loaded into the CNPs via a dialysis method. DOX-loaded CNPs (DOX-CNPs) had stable nanoparticle structures with an average size of 265.9 ± 35.5 nm in aqueous condition. In cultured cells, HIFU-treated DOX-CNPs showed rapid drug release and enhanced cellular uptake in A549 cells, resulting in increased cytotoxicity, compared to untreated DOX-CNPs. In ECM-rich A549 tumor-bearing mice, the tumor-targeting efficacy of intravenously injected DOX-CNPs with HIFU treatment was 1.84 times higher than that of untreated DOX-CNPs. Furthermore, the deep tumor penetration of HIFU-treated DOX-CNPs was clearly observed at targeted tumor tissues, due to the destruction of the ECM structure via HIFU treatment. Finally, HIFU-treated DOX-CNPs greatly increased the therapeutic efficacy at ECM-rich A549 tumor-bearing mice, compared to free DOX and untreated DOX-CNPs. This deep penetration of drug-loaded nanoparticles via HIFU treatment is a promising strategy to treat heterogeneous tumors with dense ECM structures.

Next-Generation Polymeric Nanomedicines for Oncology: Perspectives and Future Directions

Precision polymers as advanced nanomedicines represent an appealing approach for the treatment of otherwise untreatable malignancies. By taking advantage of unique nanomaterial properties and implementing judicious design strategies, polymeric nanomedicines are able to be produced that overcome many barriers to effective treatment. Current key research focus areas anticipated to produce the greatest impact in polymer applications in nanomedicine for oncology include new strategies to achieve "active" targeting, polymeric pro-drug activation, and combinatorial polymer drug delivery approaches in combination with enhanced understanding of complex bio-nano interactions. These approaches, both in isolation or combination, form the next generation of precision nanomedicines with significant anticipated future health outcomes. Of necessity, these approaches will combine an intimate understanding of biological interactions with advanced materials design. This perspectives piece aims to highlight emerging opportunities that promise to be game changers in the nanomedicine oncology field. Discussed herein are current and next generation polymeric nanomedicines with a focus towards structures that are, or could, undergo clinical translation as well as highlight key advances in the field.

Drug-internalized bacterial swimmers for magnetically manipulable tumor-targeted drug delivery

Tumor-targeted drug carriers are becoming attractive for precise drug delivery in anti-tumor therapy. However, a lot of the reported drug delivery systems are complicatedly designed and their destiny in vivo is beyond our control, which limited their clinical applications. Hence, it is urgently needed to develop spatio-manipulable self-propelled nanosystems for drug delivery in a facile way. Here, we have successfully constructed drug-internalized bacterial swimmers, whose movement can be manually controlled by an external magnetic field (MF). We demonstrate that the swimmers maintain the mobility to align and swim along MF lines. Further studies reveal that the doxorubicin (DOX-) internalized bacterial swimmers are able to navigate toward tumor sites under the guidance of MF, rendering enhanced anti-tumor efficacy compared with that of dead ones and free DOX. Therefore, the MF-guided bacterial swimmers hold great promise for spatio-manipulable drug delivery in precision medicine.

Bio-orthogonal click-targeting nanocomposites for chemo-photothermal synergistic therapy in breast cancer

Chemo-photothermal synergistic treatment has a high potential to complement traditional cancer therapy and amplify its outcome. Precision in the delivery of these therapeutic agents to tumor cells has been indicated as being key to maximizing their therapeutic effects. Method: We developed a bio-orthogonal copper-free click-targeting nanocomposite system (DLQ/DZ) that markedly improved specific co-delivery of the chemotherapeutic agent doxorubicin and the photosensitizer zinc phthalocyanine to breast cancer cells via a two-step mechanism. In the first step, an azide-modified sugar (tetraacetylated N-azidoacetyl-D-mannosamine, Ac4ManNAz) was injected intratumorally for glycoengineering of the tumor cell surface. Subsequently, DLQ/DZ was administered to achieve tumor enrichment via bio-orthogonal copper-free click-targeting. Results: During the first step in our experiments, high density azide groups (3.23×107/cell) were successfully glycoengineered on the surface of tumor cells following Ac4ManNAz administration in vitro. Subsequently, the highly efficient bio-orthogonal click chemical reaction between receptor-like azide groups on tumor cells and DBCO on nanocomposites significantly enhanced the cellular uptake and tumor-specific distribution (4.6x increase) of the nanocomposites in vivo. Importantly, Ac4ManNAz+DLQ/DZ treatment augmented the anti-cancer effect of combined chemotherapy and PTT (96.1% inhibition rate), nearly ablating the tumor. Conclusions: This bio-orthogonal click-targeting combination strategy may provide a promising treatment approach for surficial breast cancers.

Two-step tumor-targeting therapy via integrating metabolic lipid-engineering with in situ click chemistry

A highly efficient two-step targeting strategy integrating metabolic lipid-engineering with in situ click chemistry is developed, thus significantly improved the tumor theranostic performance of the red blood cells ghosts based drug delivery.

NanoRNP Overcomes Tumor Heterogeneity in Cancer Treatment

Tumor heterogeneity has been one of the most important factors leading to the failure of conventional cancer therapies due to the accumulation of genetically distinct tumor-cell subpopulations during the tumor development process. Due to the diversity of genetic mutations during tumor growth, combining the use of multiple drugs has only achieved limited success in combating heterogeneous tumors. Herein, we report a novel antitumor strategy that effectively addresses tumor heterogeneity by using a CRISPR/Cas9-based nanoRNP carrying a combination of sgRNAs. Such nanoRNP is synthesized from Cas9 ribonucleoprotein, any combinations of required sgRNAs, and a rationally designed responsive polymer that endows nanoRNP with high circulating stability, enhanced tumor accumulation, and the efficient gene editing in targeted tumor cells eventually. By carrying a combination of sgRNAs that targets STAT3 and RUNX1, the nanoRNP exhibited efficient gene expression disruptions on a heterogeneous tumor model with two subsets of cells whose proliferations were sensitive to the reduced expression of STAT3 and RUNX1, respectively, leading to the effective growth inhibition of the heterogeneous tumor. Considering the close relationship between tumor heterogeneity and cancer progression, resistance to therapy, and recurrences, nanoRNP provides a feasible strategy to overcome tumor heterogeneity in the development of more advanced cancer therapy against malignant tumors.

Rationally Designed Antibody Drug Conjugates Targeting the Breast Cancer-Associated Endothelium

The promise of antiangiogenic therapy for the treatment of breast cancer has been limited by the inability to selectively disrupt the established tumor vasculature. Here, we report the development of rationally designed antibody drug conjugates (ADCs) that can selectively recognize and attack breast tumor-associated endothelial cells (BTECs), while sparing normal endothelial cells (NECs). We first performed a quantitative and unbiased screening of a panel of cancer-related antigens on human BTECs and identified CD105 as the optimal ADC target on these cells. We then used clinically approved ADC linkers and cytotoxic drugs to engineer two CD105-targeted ADCs: CD105-DM1 and CD105-MMAE and evaluated their in vitro efficacy in human BTECs and NECs. We found that both CD105-DM1 and CD105-MMAE exhibited highly potent and selective cytotoxicity against BTECs with IC₅₀ values of 3.2 and 3.7 nM, respectively, significantly lower than their IC₅₀ values on NECs (8-13 fold). Our proof-of-principle study suggests that CD105-targeted ADCs are promising antiangiogenic agents that have the potential to be used to inhibit the established tumor vasculature of breast tumors in a safe and precise manner.

Voxel based comparison and texture analysis of 18F-FDG and 18F-FMISO PET of patients with head-and-neck cancer

Background

Hypoxia can induce radiation resistance and is an independent prognostic marker for outcome in head and neck cancer. As ¹⁸F-FMISO (FMISO), a hypoxia tracer for PET, is far less common than ¹⁸F-FDG (FDG) and two separate PET scans result in doubled cost and radiation exposure to the patient, we aimed to predict hypoxia from FDG PET with new techniques of voxel based analysis and texture analysis.

Methods

Thirty-eight patients with head-and-neck cancer underwent consecutive FDG and FMISO PET scans before any treatment. ROIs enclosing the primary cancer were compared in a voxel-by-voxel manner between FDG and FMISO PET. Tumour hypoxia was defined as the volume with a tumour-to-muscle ratio (TMR) > 1.25 in the FMISO PET and hypermetabolic volume was defined as >50% SUVmax in the FDG PET. The concordance rate was defined as percentage of voxels within the tumour which were both hypermetabolic and hypoxic. 38 different texture analysis (TA) parameters were computed based on the ROIs and correlated with presence of hypoxia.

Results

Within the hypoxic tumour regions, the FDG uptake was twice as high as in the non-hypoxic tumour regions (SUVmean 10.9 vs. 5.4; p<0.001). A moderate correlation between FDG and FMISO uptake was found by a voxel-by-voxel comparison (r = 0.664 p<0.001). The average concordance rate was 25% (± 22%). Entropy was the TA parameter showing the highest correlation with hypoxia (r = 0.524 p<0.001).

Conclusion

FDG uptake was higher in hypoxic tumour regions than in non-hypoxic regions as expected by tumour biology. A moderate correlation between FDG and FMISO PET was found by voxel-based analysis. TA yielded similar results in FDG and FMISO PET. However, it may not be possible to predict tumour hypoxia even with the help of texture analysis.

Electrospun Polylactic Acid (PLLA) Microtube Array Membrane (MTAM)-An Advanced Substrate for Anticancer Drug Screening

The advent of personalized cancer treatment resulted in the shift from the administration of cytotoxic drugs with broad activity spectrum to a targeted tumor-specific therapy. Aligned to this development, the focus of this study revolved around the application of our novel and patented microtube array membrane (MTAM) in the US National Cancer Institute (NCI) developed an HFA (hollow fiber assay) assay; hereinafter known as MTAM/HFA. Electrospun poly-L-lactic acid (PLLA) MTAM was sterilized and loaded with cell lines/patient derived tumor cells (PDTC) and subcutaneously implanted into the backs of BALB/C mice. Anticancer drugs were administered at the respective time points and the respective MTAMs were retrieved and the viability tumor cells within were quantified with the MTT assay. Results revealed that the MTAMs were excellent culture substrate for various cancer cell lines and PDTCs (patient derived tumor cells). Compared to traditional HFA systems that utilize traditional hollow fibers, MTAM/HFA revealed superior drug sensitivity for a wide range of anticancer drug classes. Additionally, the duration for each test was <14 days; all this while capable of producing similar trend outcome to the current gold-standard xenograft models. These benefits were observed in both the in vitro and in vivo stages, making it a highly practical phenotypic-based solution that could potentially be applied in personalized medicine.