Integrated metabolomics and transcriptomics analysis highlight key pathways involved in the somatic embryogenesis of Darjeeling tea.

BACKGROUND: Darjeeling tea is a globally renowned beverage, which faces numerous obstacles in sexual reproduction, such as self-incompatibility, poor seed germination, and viability, as well as issues with vegetative propagation. Somatic embryogenesis (SE) is a valuable method for rapid clonal propagation of Darjeeling tea. However, the metabolic regulatory mechanisms underlying SE in Darjeeling tea remain largely unknown. To address this, we conducted an integrated metabolomics and transcriptomics analysis of embryogenic callus (EC), globular embryo (GE), and heart-shaped embryo (HE). RESULTS: The integrated analyses showed that various genes and metabolites involved in the phenylpropanoid pathway, auxin biosynthesis pathway, gibberellin, brassinosteroid and amino acids biosynthesis pathways were differentially enriched in EC, GE, and HE. Our results revealed that despite highly up-regulated auxin biosynthesis genes YUC1, TAR1 and AAO1 in EC, endogenous indole-3-acetic acid (IAA) was significantly lower in EC than GE and HE. However, bioactive Gibberellin A4 displayed higher accumulation in EC. We also found higher BABY BOOM (BBM) and Leafy cotyledon1 (LEC1) gene expression in GE along with high accumulation of castasterone, a brassinosteroid. Total flavonoids and phenolics levels were elevated in GE and HE compared to EC, especially the phenolic compound chlorogenic acid was highly accumulated in GE. CONCLUSIONS: Integrated metabolome and transcriptome analysis revealed enriched metabolic pathways, including auxin biosynthesis and signal transduction, brassinosteroid, gibberellin, phenylpropanoid biosynthesis, amino acids metabolism, and transcription factors (TFs) during SE in Darjeeling tea. Notably, EC displayed lower endogenous IAA levels, conducive to maintaining differentiation, while higher IAA concentration in GE and HE was crucial for preserving embryo identity. Additionally, a negative correlation between bioactive gibberellin A4 (GA4) and IAA was observed, impacting callus growth in EC. The high accumulation of chlorogenic acid, a phenolic compound, might contribute to the low success rate in GE and HE formation in Darjeeling tea. TFs such as BBM1, LEC1, FUS3, LEA, WOX3, and WOX11 appeared to regulate gene expression, influencing SE in Darjeeling tea.

Cryo-EM structure of the human cardiac myosin filament.

Pumping of the heart is powered by filaments of the motor protein myosin that pull on actin filaments to generate cardiac contraction. In addition to myosin, the filaments contain cardiac myosin-binding protein C (cMyBP-C), which modulates contractility in response to physiological stimuli, and titin, which functions as a scaffold for filament assembly1. Myosin, cMyBP-C and titin are all subject to mutation, which can lead to heart failure. Despite the central importance of cardiac myosin filaments to life, their molecular structure has remained a mystery for 60 years2. Here we solve the structure of the main (cMyBP-C-containing) region of the human cardiac filament using cryo-electron microscopy. The reconstruction reveals the architecture of titin and cMyBP-C and shows how myosin's motor domains (heads) form three different types of motif (providing functional flexibility), which interact with each other and with titin and cMyBP-C to dictate filament architecture and function. The packing of myosin tails in the filament backbone is also resolved. The structure suggests how cMyBP-C helps to generate the cardiac super-relaxed state3; how titin and cMyBP-C may contribute to length-dependent activation4; and how mutations in myosin and cMyBP-C might disturb interactions, causing disease5,6. The reconstruction resolves past uncertainties and integrates previous data on cardiac muscle structure and function. It provides a new paradigm for interpreting structural, physiological and clinical observations, and for the design of potential therapeutic drugs.

Polymersome Membrane Engineering with Active Targeting or Controlled Permeability for Responsive Drug Delivery.

Polymersomes have been extensively investigated for drug delivery as nanocarriers for two decades due to a series of advantages including high stability under physiological conditions, simultaneous encapsulation of hydrophilic and hydrophobic drugs inside inner cavities and membranes, respectively, and facile adjustment of membrane and surface properties, as well as controlled drug release through incorporation of stimuli-responsive components. Despite these features, polymersome nanocarriers frequently suffer from nontargeting delivery and poor membrane permeability. In recent years, polymersomes have been functionalized for more efficient drug delivery. The surface shells were explored to be modified with diverse active targeting groups to improve disease-targeting delivery. The membrane permeability of the polymersomes was adjusted by incorporation of the stimuli-responsive components for smart controlled transportation of the encapsulated drugs. Therefore, being the polymersome-biointerface, tailorable properties can be introduced by its carefully modulated engineering. This review elaborates on the role of polymersome membranes as a platform to incorporate versatile features. First, we discuss how surface functionalization facilitates the directional journey to the targeting sites toward specific diseases, cells, or intracellular organelles via active targeting. Moreover, recent advances in the past decade related to membrane permeability to control drug release are also summarized. We finally discuss future development to promote polymersomes as in vivo drug delivery nanocarriers.

Oxidation-Responsive PolyMOF Nanoparticles for Combination Photodynamic-Immunotherapy with Enhanced STING Activation.

Stimulator of interferon genes (STING) activation by STING agonists has been recognized as one of the potent and promising immunotherapy strategies. However, the immunosuppressive tumor microenvironment always hinders the therapeutic efficacy of cancer immunotherapy. In this report, we present polymeric metal-organic framework (PMOF) nanoparticles (NPs) for the combination of photodynamic therapy (PDT) and enhanced STING activation to improve the immunotherapeutic efficacy. The PMOF NPs with poly(ethylene glycol) (PEG) shells were obtained via coordination between the block copolymer ligand PEG-b-PABDA consisting of 1,4-bezenedicarboxylic acid-bearing polyacrylamide (PABDA), meso-tetra(carboxyphenyl)porphyrin (TCPP), thioketal diacetic acid, and zirconyl chloride. Subsequently, the STING agonist SR-717 was loaded into the porous structure of PMOF to obtain SR@PMOF NPs which show excellent stability under the physiological conditions. After intravenous injection and tumor accumulation, light irradiation on the tumor sites results in efficient singlet oxygen (1O2) production from TCPP and cellular apoptosis to release fragmented DNA and tumor-associated antigens. Simultaneously, thioketal bonds can be broken by 1O2 to destroy the PMOF structure and rapidly release SR717. SR-717 and PDT synergistically enhance the antitumor immunity via combination photodynamic-immunotherapy due to reversal of the immunosuppressive tumor microenvironment and enhanced endogenous STING activation, which can suppress the growth of the primary and distant tumors efficiently. The oxidation-responsive SR@PMOF NPs represent a promising delivery system of STING agonists and efficient PDT NPs for simultaneous suppression of the primary and metastatic tumors via the rational combination of PDT and enhanced STING activation.

Cryo-EM structure of the human cardiac myosin filament.

Pumping of the heart is powered by filaments of the motor protein myosin, which pull on actin filaments to generate cardiac contraction. In addition to myosin, the filaments contain cardiac myosin-binding protein C (cMyBP-C), which modulates contractility in response to physiological stimuli, and titin, which functions as a scaffold for filament assembly 1 . Myosin, cMyBP-C and titin are all subject to mutation, which can lead to heart failure. Despite the central importance of cardiac myosin filaments to life, their molecular structure has remained a mystery for 60 years 2 . Here, we have solved the structure of the main (cMyBP-C-containing) region of the human cardiac filament to 6 Å resolution by cryo-EM. The reconstruction reveals the architecture of titin and cMyBP-C for the first time, and shows how myosin's motor domains (heads) form 3 different types of motif (providing functional flexibility), which interact with each other and with specific domains of titin and cMyBP-C to dictate filament architecture and regulate function. A novel packing of myosin tails in the filament backbone is also resolved. The structure suggests how cMyBP-C helps generate the cardiac super-relaxed state 3 , how titin and cMyBP-C may contribute to length-dependent activation 4 , and how mutations in myosin and cMyBP-C might disrupt interactions, causing disease 5, 6 . A similar structure is likely in vertebrate skeletal myosin filaments. The reconstruction resolves past uncertainties, and integrates previous data on cardiac muscle structure and function. It provides a new paradigm for interpreting structural, physiological and clinical observations, and for the design of potential therapeutic drugs.

Variants of the myosin interacting-heads motif.

Under relaxing conditions, the two heads of myosin II interact with each other and with the proximal part (S2) of the myosin tail, establishing the interacting-heads motif (IHM), found in myosin molecules and thick filaments of muscle and nonmuscle cells. The IHM is normally thought of as a single, unique structure, but there are several variants. In the simplest ("canonical") IHM, occurring in most relaxed thick filaments and in heavy meromyosin, the interacting heads bend back and interact with S2, and the motif lies parallel to the filament surface. In one variant, occurring in insect indirect flight muscle, there is no S2-head interaction and the motif is perpendicular to the filament. In a second variant, found in smooth and nonmuscle single myosin molecules in their inhibited (10S) conformation, S2 is shifted ∼20 Šfrom the canonical form and the tail folds twice and wraps around the interacting heads. These molecule and filament IHM variants have important energetic and pathophysiological consequences. (1) The canonical motif, with S2-head interaction, correlates with the super-relaxed (SRX) state of myosin. The absence of S2-head interaction in insects may account for the lower stability of this IHM and apparent absence of SRX in indirect flight muscle, contributing to the quick initiation of flight in insects. (2) The ∼20 Šshift of S2 in 10S myosin molecules means that S2-head interactions are different from those in the canonical IHM. This variant therefore cannot be used to analyze the impact of myosin mutations on S2-head interactions that occur in filaments, as has been proposed. It can be used, instead, to analyze the structural impact of mutations in smooth and nonmuscle myosin.

Multifunctional Mesoporous Hollow Cobalt Sulfide Nanoreactors for Synergistic Chemodynamic/Photodynamic/Photothermal Therapy with Enhanced Efficacy.

The unique tumor microenvironment (TME) characteristic of severe hypoxia, overexpressed intracellular glutathione (GSH), and elevated hydrogen peroxide (H2O2) concentration limit the anticancer effect by monotherapy. In this report, glucose oxidase (GOx)-encapsulated mesoporous hollow Co9S8 nanoreactors are constructed with the coverage of polyphenol diblock polymers containing poly(oligo(ethylene glycol) methacrylate) and dopamine moieties containing methacrylate polymeric block, which are termed as GOx@PCoS. After intravenous injection, tumor accumulation, and cellular uptake, GOx@PCoS deplete GSH by Co3+ ions. GOx inside the nanoreactors produce H2O2 via oxidation of glucose to enhance •OH-based chemodynamic therapy (CDT) through the Fenton-like reaction under the catalysis of Co2+. Moreover, Co3+ ions possess catalase activity to catalyze production of O2 from H2O2 to relieve tumor hypoxia. Upon 808 nm laser irradiation, GOx@PCoS exhibit photothermal and photodynamic effects with a high photothermal conversion efficiency (45.06%) and generation capacity of the toxic superoxide anion (•O2-) for photothermal therapy (PTT) and photodynamic therapy (PDT). The synergetic antitumor effects can be realized by GSH depletion, starvation, and combined CDT, PTT, and PDT with enhanced efficacy. Notably, GOx@PCoS can also be used as a magnetic resonance imaging (MRI) contrast agent to monitor the antitumor performance. Thus, GOx@PCoS show great potentials to effectively modulate TME and perform synergistic multimodal therapy.

Protein-Delivering Nanocomplexes with Fenton Reaction-Triggered Cargo Release to Boost Cancer Immunotherapy.

Immunotherapeutic efficacy of tumors based on immune checkpoint blockade (ICB) therapy is frequently limited by an immunosuppressive tumor microenvironment and cross-reactivity with normal tissues. Herein, we develop reactive oxygen species (ROS)-responsive nanocomplexes with the function of ROS production for delivery and triggered release of anti-mouse programmed death ligand 1 antibody (αPDL1) and glucose oxidase (GOx). GOx and αPDL1 were complexed with oligomerized (-)-epigallocatechin-3-O-gallate (OEGCG), which was followed by chelation with Fe3+ and coverage of the ROS-responsive block copolymer, POEGMA-b-PTKDOPA, consisting of poly(oligo(ethylene glycol)methacrylate) (POEGMA) and the block with thioketal bond-linked dopamine moieties (PTKDOPA) as the side chains. After intravenous injection, the nanocomplexes show prolonged circulation in the bloodstream with a half-life of 8.72 h and efficient tumor accumulation. At the tumor sites, GOx inside the nanocomplexes can produce H2O2 via oxidation of glucose for Fenton reaction to generate hydroxyl radicals (•OH) which further trigger the release of the protein cargos through ROS-responsive cleavage of thioketal bonds. The released GOx improves the production efficiency of •OH to kill cancer cells for release of tumor-associated antigens via chemodynamic therapy (CDT). The enhanced immunogenic cell death (ICD) can activate the immunosuppressive tumor microenvironment and improve the immunotherapy effect of the released αPDL1, which significantly suppresses primary and metastatic tumors. Thus, the nanocomplexes with Fenton reaction-triggered protein release show great potentials to improve the immunotherapeutic efficacy of ICB via combination with CDT.

Covalent Organic Framework Nanocarriers of Singlet Oxygen for Oxygen-Independent Concurrent Photothermal/Photodynamic Therapy to Ablate Hypoxic Tumors.

Photodynamic therapy (PDT) of cancers is seriously restricted by tumor hypoxia. In addition to the intrinsic hypoxic microenvironment, continuous photoirradiation further aggravates intratumoral hypoxia, thereby reducing the PDT effect significantly. Oxygen-independent PDT is recognized as an efficient approach to overcome this issue. Herein, singlet oxygen (1 O2 )-stored covalent organic framework (COF) nanoparticles loading the near-infrared (NIR) dye cypate, which realize oxygen-independent 1 O2 production for concurrent photothermal therapy (PTT) and PDT under NIR irradiation, are presented. The cypate-loading COF nanoparticles are prepared by using the photosensitizers and 1 O2 -stored molecules via formation of Schiff base bonds, followed by coverage of poly(vinyl pyrrolidone). The COF nanoparticles significantly improve the photostability and photothermal conversion efficiency of cypate by protecting them from photodegradation under NIR irradiation. Upon 660 nm laser irradiation, 1 O2 is produced by the photosensitizer motifs and is successfully stored by the 1 O2 -stored moieties. After intravenous injection and tumor accumulation, the COF nanoparticles can generate heat quickly upon 808 nm irradiation which induces the efficient release of the stored 1 O2 to ablate tumors via O2 -independent concurrent PTT/PDT. Accordingly, the COF nanocarriers of 1 O2 provide a paradigm to develop O2 -independent concurrent PTT/PDT for precise cancer treatment upon NIR irradiation.

Glutathione-Triggered Mitochondria-Targeting Reassembly from Polymeric Micelles to Nanofibers for a Synergistic Anticancer Effect.

Nanofibers self-assembled from peptides have attracted much attention to inhibit cancer cells. However, there are still some disadvantages, including high concentration for self-assembly and incapability to load drugs, which limit their applications. In this report, we rationally integrate self-assembled peptides, glutathione-sensitive disulfide bonds, and mitochondrial targeting moieties into the amphiphilic block copolymer to construct the nanocarriers, which can be used to load anticancer drug doxorubicin (DOX). After cellular internalization, the nanocarriers can reassemble from micelles to nanofibers under the trigger by glutathione and locate in mitochondria. The released DOX and nanofibers induce mitochondrial dysfunction and activate the apoptosis pathway to synergistically inhibit tumor cells. This organelle-specific drug delivery system with reassembly capability from micelles to nanofibers shows great potential for effectively killing cancer cells.

Validation of determinate (dt) gene-based DNA marker in inter-specific hybrid sesame and in-silico analysis of the predicted dt protein structures.

Determinacy is a desirable trait in sesame, an important oilseed crop. We have developed an inter-specific hybrid between basally branched indeterminate cultivated Sesamum indicum genotype and wild S. prostratum with no branching yet synchronous pods on the shoot. The hybrid and a few exotic sesame germplasms were successfully screened with a determinacy (dt) gene-based DNA marker. In-silico translation of the partial coding sequences of the dt gene from the two contrasting parent genotypes revealed an SNP (V159A) in S. prostratum. The predicted cytoplasmic dt protein showed a high resemblance with flowering protein centroradialis. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s12298-022-01135-1.

Hypoxia-Responsive Polyprodrug Nanocarriers for Near-Infrared Light-Boosted Photodynamic Chemotherapy.

The hypoxia environment inside tumors is tightly associated with tumor growth, metastasis, and drug resistance. However, the heterogonous distribution of hypoxic areas limits the efficacy of hypoxia-activatable drug delivery systems. Herein, we report the hypoxia-activable block copolymer polyprodrugs, which are composed of poly(ethylene glycol) (PEG) and copolymerized segments of ortho-nitrobenzyl-linked camptothecin (CPT) methacrylate and 2-(piperidin-1-yl)ethyl methacrylate (PEMA) monomers. After self-assembly in aqueous solution, indocyanine green (ICG) photosensitizers were encapsulated to formulate ICG-loaded micellar nanoparticles (ICG@CPTNB) for near-infrared (NIR) light-boosted photodynamic therapy (PDT), tumor hypoxia aggravation, and responsive drug activation. Through intravenous injection and prolonged blood circulation, the nanoparticles can accumulate into tumor efficiently. Tumor acidity-triggered charge transition of PEMA units remarkably promotes cellular internalization of the nanoparticles. Upon exposure to NIR laser irradiation, ICG inside the nanoparticles produced reactive oxygen species (ROS) along with local hypothermia. Simultaneously, the oxygen consumption during ROS production aggravated the intratumoral hypoxia, which amplified hypoxia-responsive self-immolative CPT release from the nanoparticles. The combined photodynamic chemotherapy using hypoxia-responsive polyprodrug nanoparticles, ICG@CPTNB, overcomes the limitations of single therapy of hypoxia-activable prodrugs or PDT, which remarkably improves the efficiency of tumor growth suppression.

Label-Free Method Development for Hydroxyproline PTM Mapping in Human Plasma Proteome.

Post-translational modifications (PTMs) impart structural heterogeneities that can alter plasma proteins' functions in various pathophysiological processes. However, the identification and mapping of PTMs in untargeted plasma proteomics is still a challenge due to the presence of diverse components in blood. Here, we report a label-free method for identifying and mapping hydroxylated proteins using tandem mass spectrometry (MS/MS) in the human plasma sample. Our untargeted proteomics approach led us to identify 676 de novo sequenced peptides in human plasma that correspond to 201 proteins, out of which 11 plasma proteins were found to be hydroxylated. Among these hydroxylated proteins, Immunoglobulin A1 (IgA1) heavy chain was found to be modified at residue 285 (Pro285 to Hyp285), which was further validated by MS/MS study. Molecular dynamics (MD) simulation analysis demonstrated that this proline hydroxylation in IgA1 caused both local and global structural changes. Overall, this study provides a comprehensive understanding of the protein profile containing Hyp PTMs in human plasma and shows the future perspective of identifying and discriminating Hyp PTM in the normal and the diseased proteomes.

Using a Secure, Continually Updating, Web Source Processing Pipeline to Support the Real-Time Data Synthesis and Analysis of Scientific Literature: Development and Validation Study.

BACKGROUND: The scale and quality of the global scientific response to the COVID-19 pandemic have unquestionably saved lives. However, the COVID-19 pandemic has also triggered an unprecedented "infodemic"; the velocity and volume of data production have overwhelmed many key stakeholders such as clinicians and policy makers, as they have been unable to process structured and unstructured data for evidence-based decision making. Solutions that aim to alleviate this data synthesis-related challenge are unable to capture heterogeneous web data in real time for the production of concomitant answers and are not based on the high-quality information in responses to a free-text query. OBJECTIVE: The main objective of this project is to build a generic, real-time, continuously updating curation platform that can support the data synthesis and analysis of a scientific literature framework. Our secondary objective is to validate this platform and the curation methodology for COVID-19-related medical literature by expanding the COVID-19 Open Research Dataset via the addition of new, unstructured data. METHODS: To create an infrastructure that addresses our objectives, the PanSurg Collaborative at Imperial College London has developed a unique data pipeline based on a web crawler extraction methodology. This data pipeline uses a novel curation methodology that adopts a human-in-the-loop approach for the characterization of quality, relevance, and key evidence across a range of scientific literature sources. RESULTS: REDASA (Realtime Data Synthesis and Analysis) is now one of the world's largest and most up-to-date sources of COVID-19-related evidence; it consists of 104,000 documents. By capturing curators' critical appraisal methodologies through the discrete labeling and rating of information, REDASA rapidly developed a foundational, pooled, data science data set of over 1400 articles in under 2 weeks. These articles provide COVID-19-related information and represent around 10% of all papers about COVID-19. CONCLUSIONS: This data set can act as ground truth for the future implementation of a live, automated systematic review. The three benefits of REDASA's design are as follows: (1) it adopts a user-friendly, human-in-the-loop methodology by embedding an efficient, user-friendly curation platform into a natural language processing search engine; (2) it provides a curated data set in the JavaScript Object Notation format for experienced academic reviewers' critical appraisal choices and decision-making methodologies; and (3) due to the wide scope and depth of its web crawling method, REDASA has already captured one of the world's largest COVID-19-related data corpora for searches and curation.

Transcriptomic dataset of cultivated (Sesamum indicum), wild (S. mulayanum), and interspecific hybrid sesame in response to induced Macrophomina phaseolina infection.

We report here the data of transcriptome sequencing of control and infected sesame genotypes. Sesame is an emerging oilseed crop [1]. The destructive soil-borne fungi Macrophomina phaseolina Tassi (Goid) causes charcoal rot of sesame, leading to high (>50%) yield loss. Most of the high-yielding sesame cultivars (Sesamum indicum) of India are susceptible to charcoal rot. Wild sesame, Sesamum mulayanum shows a high degree of tolerance against many pathogens [2]. We have earlier developed an interspecific hybrid between Indian cultivated sesame and S. mulayanum. The parents and the F6 recombinant constitute the three experimental genotypes in the present report. The seedlings were infected with M. phaseolina. The data of the infected and control (mock-inoculated) transcriptome is presented. The RNA-seq by Illumina NovaSeq 6000 technology generated 2.9 × 108 paired-end reads. We deposited the data in NCBI sequence read archive (SRA) with accession number PRJNA642699. The de novo assembly of clean reads generated 106,295 unigenes with an average length of 1,342 bp covering 1.42 × 108 nucleotides. The screening of 106,295 unigenes with MISA and SAMtools software resulted in the identification of 26,880 simple sequence repeats (SSRs), 90,181 single nucleotide polymorphisms (SNPs), and 25,063 insertion deletions (InDels). Apart from mono-base repeats, di-nucleotides repeats (42.51%) were found to be the most abundant, followed by tri-nucleotides (14.28%) among the SSRs. Subsequently, we have designed 22,494 pairs of primers based on perfect di and tri-nucleotide SSRs. Transitions (Ts, 60%) were the most abundant substitution type among the SNPs followed by transversions type (Tv, 40%), with a Ts/Tv ratio of 1.48. The development of genic-SSR markers and SNP information will pave the way for molecular marker-assisted breeding of sesame for tolerance against charcoal rot.

Staphylococcal superantigen-like proteins interact with human MAP kinase signaling protein ERK2.

This study aimed to identify the intracellular binding partner of a unique class of staphylococcal secreted exotoxins called superantigen-like proteins (SSL) from human macrophage and keratinocyte cell lysates. Here, we report that SSL1 specifically binds to human extracellular signal-regulated kinase 2 (hERK2), an important stress-activated kinase in mitogen-activated protein kinase signaling pathways. Western blot and in vitro binding studies with recombinant hERK2 confirmed the binding interaction of SSL1, SSL7, and SSL10 with hERK2. Moreover, the SSLs-hERK2 interaction was validated biochemically by ELISA. Our finding shows that SSLs play a novel role by binding with host cell MAP kinase signaling pathway protein. Understanding the SSL-hERK2 interaction will also provide a basis for designing SSL-based peptide inhibitors of hERK2 in cancer therapy.

Block copolymer prodrugs: Synthesis, self-assembly, and applications for cancer therapy.

Block copolymer prodrugs (BCPs) have emerged as one of the most promising anticancer drug delivery strategies, which can self-assemble into nanoparticles with optimal physicochemical properties including sizes, morphologies, surface properties, and integration of multifunction for improved in vivo applications. Moreover, the utility of stimuli-responsive linkages to conjugate drugs onto the polymer backbones can achieve efficient and targeting drug release. Several BCP micellar delivery systems have been pushed ahead into the clinical trials, which showed great promising potentials for cancer therapy. In recent years, various novel and more efficient BCP systems have been developed for better in vivo performance. In this focus article, we focus on the recent advances of BCPs including the synthesis, self-assembly, and applications for cancer therapy. The synthetic methods are first introduced, and the self-assembly of BCPs for in vivo anticancer applications is discussed along the line of varying endogenous stimuli-responsive linkages including amide or ester bonds, pH, reduction, and oxidation-responsive linkages. Finally, conclusions along with the brief future perspectives are presented. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease Nanotechnology Approaches to Biology > Nanoscale Systems in Biology.

Length effect of stimuli-responsive block copolymer prodrug filomicelles on drug delivery efficiency.

Filomicelles possess some unique properties for improved in vivo drug delivery efficiency relative to commonly used spherical nanocarriers, which have attracted great interests. However, the length effect of the block copolymer prodrug-based filomicelles with a comparable cross-section diameter on the drug delivery efficiency and antitumor efficacy still need to be systematically studied. In this report, we prepare three optimized nanoparticles with a comparable cross-section diameter of ~40 nm, including long filomicelles (LFMs) with the length of ~2.5 µm, short filomicelles (SFMs) with the length of ~180 nm, and spherical micelles (SMs) with a diameter of ~40 nm. All of them are self-assembled from the pH and oxidation dual-responsive block copolymer prodrug, PEG-b-P(CPTKMA-co-PEMA), consisting of poly(ethylene glycol) (PEG) and a copolymerized block of thioketal-linked camptothecin methacrylate (CPTKMA) and 2-(pentamethyleneimino) ethyl methacrylate (PEMA). At pH 6.5, the nanoparticles are positively charged due to the protonation of PPEMA segments. Among them, SFMs are demonstrated to be internalized into cells most efficiently at pH 6.5 due to larger interaction areas with cell membranes relative to SMs. Moreover, SFMs show prolonged blood circulation similar to SMs as well as deepest tumor penetration and best antitumor efficacy among the three nanoparticles. LFMs show worst in vivo performance because their too long structure limits the cellular uptake and tumor accumulation. Therefore, the responsive polymer prodrug filomicelles with an optimized length show great potentials to overcome the physiological barriers and improve the drug delivery efficiency.

Isolation and mass spectrometry based hydroxyproline mapping of type II collagen derived from Capra hircus ear cartilage.

Collagen II (COLII), the most abundant protein in vertebrates, helps maintain the structural and functional integrity of cartilage. Delivery of COLII from animal sources could improve cartilage regeneration therapies. Here we show that COLII can be purified from the Capra ear cartilage, a commonly available bio-waste product, with a high yield. MALDI-MS/MS analysis evidenced post-translational modifications of the signature triplet, Glycine-Proline-Hydroxyproline (G-P-Hyp), in alpha chain of isolated COLII (COLIIA1). Additionally, thirty-two peptides containing 59 Hyp residues and a few G-X-Y triplets with positional alterations of Hyp in COLIIA1 are also identified. Furthermore, we show that an injectable hydrogel formulation containing the isolated COLII facilitates chondrogenic differentiation towards cartilage regeneration. These findings show that COLII can be isolated from Capra ear cartilage and that positional alteration of Hyp in its structural motif, as detected by newly developed mass spectrometric method, might be an early marker of cartilage disorder.

Multi-nucleated cells use ROS to induce breast cancer chemo-resistance in vitro and in vivo.

Although there is a strong correlation between multinucleated cells (MNCs) and cancer chemo-resistance in variety of cancers, our understanding of how multinucleated cells modulate the tumor micro-environment is limited. We captured multinucleated cells from triple-negative chemo-resistant breast cancers cells in a time frame, where they do not proliferate but rather significantly regulate their micro-environment. We show that oxidatively stressed MNCs induce chemo-resistance in vitro and in vivo by secreting VEGF and MIF. These factors act through the RAS/MAPK pathway to induce chemo-resistance by upregulating anti-apoptotic proteins. In MNCs, elevated reactive oxygen species (ROS) stabilizes HIF-1α contributing to increase production of VEGF and MIF. Together the data indicate, that the ROS-HIF-1α signaling axis is very crucial in regulation of chemo-resistance by MNCs. Targeting ROS-HIF-1α in future may help to abrogate drug resistance in breast cancer.