Uncovering the Binding Specificities of Lectins with Cells for Precision Colorectal Cancer Diagnosis Based on Multimodal Imaging

Lectin microarray based glycan profiling of exosomes for dynamic monitoring of colorectal cancer progression

BACKGROUND

Exosomes, as emerging biomarkers in liquid biopsies in recent years, offer profound insights into cancer diagnostics due to their unique molecular signatures. The glycosylation profiles of exosomes have emerged as potential biomarkers, offering a novel and less invasive method for cancer diagnosis and monitoring. Colorectal cancer (CRC) represents a substantial global health challenge and burden. Thus there is a great need for the aberrant glycosylation patterns on the surface of CRC cell-derived exosomes, proposing them as potential biomarkers for tumor characterization.

RESULTS

The interactions of 27 lectins with exosomes from three CRC cell lines (SW480, SW620, HCT116) and one normal colon epithelial cell line (NCM460) have been analyzed by the lectin microarray. The result indicates that Ulex Europaeus Agglutinin I (UEA-I) exhibits high affinity and specificity towards exosomes derived from SW480 cells. The expression of glycosylation related genes within cells has been analyzed by high-throughput quantitative polymerase chain reaction (HT-qPCR). The experimental result of HT-qPCR is consistent with that of lectin microarray. Moreover, the limit of detection (LOD) of UEA-I microarray is calculated to be as low as 2.7 × 105 extracellular vehicles (EVs) mL-1 (three times standard deviation (3σ) of blank sample). The UEA-I microarray has been successfully utilized to dynamically monitor the progression of tumors in mice-bearing SW480 CRC subtype, applicable in tumor sizes ranging from 2 mm to 20 mm in diameter.

SIGNIFICANCE

The results reveal that glycan expression pattern of exosome is linked to specific CRC subtypes, and regulated by glycosyltransferase and glycosidase genes of mother cells. Our findings illuminate the potential of glycosylation molecules on the surface of exosomes as reliable biomarkers for diagnosis of tumor at early stage and monitoring of cancer progression.

Upconversion nanoparticle-based fluorescence resonance energy transfer sensing platform for the detection of cathepsin B activity in vitro and in vivo

A simple fluorescence resonance energy transfer (FRET) sensing platform (termed as USP), comprised of upconversion nanoparticles (UCNPs) as the energy donor and Cy5 as the energy acceptor, has been synthesized for cathepsin B (CTSB) activity detection in vitro and in vivo. When Cy5-modified peptide substrate (peptide-Cy5) of CTSB is covalently linked on the surface of UCNPs, the FRET between the UCNPs (excitation: 980 nm; emission: 541 nm/655 nm) and Cy5 (excitation: 645 nm) leads to a reduction in the red upconversion luminescence (UCL) signal intensity of UCNPs. Cy5 can be liberated from UCNPs in the presence of CTSB through the cleavage of peptide-Cy5 by CTSB, leading to the recovery of the red UCL signal of UCNPs. Because the green UCL signal of UCNPs remains constant during the CTSB digestion, it can be considered as an internal reference. The findings demonstrate the ability of USP to detect CTSB with the linear detection ranges of 1 to 100 ng·mL^-1 in buffer and 2 × 10³ to 1 × 10⁵ cells in 0.2 mL cell lysates. The limits of detection (LODs) are 0.30 ng·mL^-1 in buffer and 887 cells in 0.2 mL of cell lysates (S/N = 3). The viability of USP to detect CTSB activity in tumor-bearing mice is has further been investigated using in vivo fluorescent imaging.

Revisiting carboxylic group functionalization of silica sol-gel materials

The carboxylic chemical group is a ubiquitous moiety present in amino acids, a ligand for transition metals, a colloidal stabilizer, and a weak acidic ion-exchanger in polymeric resins and given this property, it is attractive for responsive materials or nanopore-based gating applications. As the number of uses increases, subtle requirements are imposed on this molecular group when anchored to various platforms for the functioning of an integrated chemical system. In this context, silica stands as an inert and multipurpose platform that enables the anchoring of multiple chemical entities combined through several orthogonal synthesis methods on the interface. Surface chemical modification relies on the use of organoalkoxysilanes that must meet the demand of tuned chemical properties; this, in turn, urges for innovative approaches for having an improved, but simple, organic toolbox. Starting from commonly available molecular precursors, several approaches have emerged: hydrosilylation, click thiol-ene additions, the use of carbodiimides or the reaction between cyclic anhydrides and anchored amines. In this review, we analyze the importance of the COOH groups in the area of materials science and the commercial availability of COOH-based silanes and present new approaches for obtaining COOH-based organoalkoxide precursors. Undoubtedly, this will attract widespread interest for the ultimate design of highly integrated chemical platforms.

An oligomeric hyaluronic acid-GX1 molecular target drug with polyvalent targeting to CD44 and VEGF receptors

The off-target toxicity of molecular targeted drug hinders its clinical transformation. Herein, we report a new molecular targeted drug oHA-GX1 constructed by oligomeric hyaluronan (oHA) and peptide GX1 (CGNSNPKSC). The oHA-GX1 can not only suppress the tumor growth by interacting with overexpressed VEGF and CD44 receptors inside tumor tissues, but also reduce the likelihood of off-target toxicity due to the multiple VEGF and CD44 receptors binding sites. The cytotoxicity study shows that the IC₅₀^oHA-GX1 against co-SGC-7901 and co-HUVEC cells fell in the range of common cytotoxic drugs. The animal experiment results reveal that the tumor inhibition rate of oHA-GX1 (100 mg/kg) against SGC-7901 tumor-bearing mice were 78.4 %, which was comparable to that of front-line chemotherapy drugs. Also, the cytotoxicity study on normal cells, hemolysis test, hemagglutination assay and the acute toxicity test demonstrate that oHA-GX1 exhibited excellent biosafety. This molecular targeted drug that utilizes the multiple receptor-binding sites to get rid of the side effects caused by off-target paves a new direction for the discovery of anticancer drugs with high efficacy and low adverse effects.

Anticancer Activity of Mannose-Specific Lectin, BPL2, from Marine Green Alga Bryopsis plumosa

Lectin is a carbohydrate-binding protein that recognizes specific cells by binding to cell-surface polysaccharides. Tumor cells generally show various glycosylation patterns, making them distinguishable from non-cancerous cells. Consequently, lectin has been suggested as a good anticancer agent. Herein, the anticancer activity of Bryopsis plumosa lectins (BPL1, BPL2, and BPL3) was screened and tested against lung cancer cell lines (A549, H460, and H1299). BPL2 showed high anticancer activity compared to BPL1 and BPL3. Cell viability was dependent on BPL2 concentration and incubation time. The IC₅₀ value for lung cancer cells was 50 μg/mL after 24 h of incubation in BPL2 containing medium; however, BPL2 (50 μg/mL) showed weak toxicity in non-cancerous cells (MRC5). BPL2 affected cancer cell growth while non-cancerous cells were less affected. Further, BPL2 (20 μg/mL) inhibited cancer cell invasion and migration (rates were ˂20%). BPL2 induced the downregulation of epithelial-to-mesenchymal transition-related genes (Zeb1, vimentin, and Twist). Co-treatment with BPL2 and gefitinib (10 μg/mL and 10 μM, respectively) showed a synergistic effect compared with monotherapy. BPL2 or gefitinib monotherapy resulted in approximately 90% and 70% cell viability, respectively, with concomitant treatment showing 40% cell viability. Overall, BPL2 can be considered a good candidate for development into an anticancer agent.

Lanthanide Ion Resonance-Driven Rayleigh Scattering of Nanoparticles for Dual-Modality Interferometric Scattering Microscopy

Light scattering from nanoparticles is significant in nanoscale imaging, photon confinement. and biosensing. However, engineering the scattering spectrum, traditionally by modifying the geometric feature of particles, requires synthesis and fabrication with nanometre accuracy. Here it is reported that doping lanthanide ions can engineer the scattering properties of low-refractive-index nanoparticles. When the excitation wavelength matches the ion resonance frequency of lanthanide ions, the polarizability and the resulted scattering cross-section of nanoparticles are dramatically enhanced. It is demonstrated that these purposely engineered nanoparticles can be used for interferometric scattering (iSCAT) microscopy. Conceptually, a dual-modality iSCAT microscopy is further developed to identify different nanoparticle types in living HeLa cells. The work provides insight into engineering the scattering features by doping elements in nanomaterials, further inspiring exploration of the geometry-independent scattering modulation strategy.

Ulex Europaeus Agglutinin-I-Based Magnetic Isolation for the Efficient and Specific Capture of SW480 Circulating Colorectal Tumor Cells

The efficient and specific capture of circulating tumor cells (CTCs) from patients' peripheral blood is of significant value in precise cancer diagnosis and cancer therapy. As fine targeting molecules, lectins can recognize cancer cells specifically due to the abnormal glycosylation of molecules on the cancer cell membrane and the specific binding of lectin with glycoconjugates. Herein, a Ulex europaeus agglutinin-I (UEA-I)-based magnetic isolation strategy was developed to efficiently and specifically capture α-1,2-fucose overexpression CTCs from colorectal cancer (CRC) patients' peripheral blood. Using UEA-I-modified Fe₃O₄ magnetic beads (termed MB-UEA-I), up to 94 and 89% of target cells (i.e., SW480 CRC cells) were captured from the cell spiking complete cell culture medium and whole blood, respectively. More than 90% of captured cells show good viability and proliferation ability without detaching from MB-UEA-I. In combination with three-color immunocytochemistry (ICC) identification, MB-UEA-I has been successfully used to capture CTCs from CRC patients' peripheral blood. The experimental results indicate a correlation between CTC characterization and tumor metastasis. Specifically, MB-UEA-I can be applied to screen early CRC by capturing CTCs when served as a liquid biopsy. The presented work offers a new insight into developing cost-effective lectin-functionalized methods for biomedical applications.

Tumor-Targeting NIRF/MR Dual-Modal Molecular Imaging Probe for Surgery Navigation

Multimodality imaging recognized as a promising monitoring strategy can serve the needs of accurate diagnosis and treatment of cancer by providing molecular and anatomic information about tumor sites. However, the probes based on multiple imaging modalities for surgery navigation remain limited due to poor biocompatibility and tumor targeting specificity. Herein, we present a small-molecule near-infrared fluorescence/magnetic resonance (NIRF/MR) imaging probe, Gd-NMC-3, covalently coupled with DCDSTCY and Gd-DOTA via butane diamine, for precise detection and intraoperative visualization. The in vitro and in vivo studies demonstrated that Gd-NMC-3 could be effectively accumulated in tumor sites as a bimodal imaging molecule exhibiting significant fluorescence accumulation and reasonable relaxation property in tumors with low cytotoxicity and good biocompatibility. Furthermore, Gd-NMC-3 was successfully applied to provide real-time visual navigation in LM3 orthotopic and subcutaneous tumor models to guide the resection of tumors. Importantly, no more fluorescence was observed in mice after operation, implying the total removal of tumor tissues. In conclusion, Gd-NMC-3 has great potential to be applied in the clinic based on its high resolution and sensitivity in tumor imaging.

Circulating Glycan Monosaccharide Composite-Based Biomarker Diagnoses Colorectal Cancer at Early Stages and Predicts Prognosis

Introduction

Early diagnosis could lead to a cure of colorectal cancer (CRC). Since CRC is related to aging and lifestyles, we tested if the environmental information-enriched monosaccharide composite (MC) of circulating glycans could serve as an early diagnostic biomarker for CRC. Meanwhile, we evaluated its role in predicting prognosis.

Methods

HPAEC-PAD was used to quantify glycan monosaccharide compositions from a total of 467 serum samples including CRC patients, colorectal adenoma (CRA) patients and healthy individuals. Two diagnostic model was constructed by logistic regression analysis. The diagnostic performance of the two models was verified in the retrospective validation group and the prospective validation group. The prognostic performance of the model was assessed by survival analysis.

Results

The concentrations of monosaccharides in serum were significantly higher in CRA and CRC patients than in healthy individuals. Two diagnostic models were constructed: MC1 was used to distinguish between healthy individuals and CRC; MC2 was used to distinguish between healthy individuals and CRA. Area under receptor operating characteristic curve (AUC) of MC2 and MC1 was 0.8025 and 0.9403 respectively. However, the AUC of CEA between healthy individuals and CRC was 0.7384. Moreover, in early stage of CRC (without lymph node metastasis), the positive rates of CEA and MC1 were 28% and 80%, respectively. The follow-up data showed that the increased MC1 value was associated with poor survival in patients with CRC (p=0.0010, HR=5.30).

Discussion

The MC1 model is superior to CEA in the diagnosis of CRC, especially in the early diagnosis. MC1 can be used for predicting prognosis of CRC patients, and elevated MC1 values indicate poor survival.

The Bioanalytical and Biomedical Applications of Polymer Modified Substrates

Polymers with different structures and morphology have been extensively used to construct functionalized surfaces for a wide range of applications because the physicochemical properties of polymers can be finely adjusted by their molecular weights, polydispersity and configurations, as well as the chemical structures and natures of monomers. In particular, the specific functions of polymers can be easily achieved at post-synthesis by the attachment of different kinds of active molecules such as recognition ligand, peptides, aptamers and antibodies. In this review, the recent advances in the bioanalytical and biomedical applications of polymer modified substrates were summarized with subsections on functionalization using branched polymers, polymer brushes and polymer hydrogels. The review focuses on their applications as biosensors with excellent analytical performance and/or as nonfouling surfaces with efficient antibacterial activity. Finally, we discuss the perspectives and future directions of polymer modified substrates in the development of biodevices for the diagnosis, treatment and prevention of diseases.

Harnessing X-Ray Energy-Dependent Attenuation of Bismuth-Based Nanoprobes for Accurate Diagnosis of Liver Fibrosis

Timely detection of liver fibrosis by X-ray computed tomography (CT) can prevent its progression to fatal liver diseases. However, it remains quite challenging because conventional CT can only identify the difference in density instead of X-ray attenuation characteristics. Spectral CT can generate monochromatic imaging to specify X-ray attenuation characteristics of the scanned matter. Herein, an X-ray energy-dependent attenuation strategy originated from bismuth (Bi)-based nanoprobes (BiF3 @PDA@HA) is proposed for the accurate diagnosis of liver fibrosis. Bi element in BiF3 @PDA@HA can exhibit characteristic attenuation depending on different levels of X-ray energy via spectral CT, and that is challenging for conventional CT. In this study, selectively accumulating BiF3 @PDA@HA nanoprobes in the hepatic fibrosis areas can significantly elevate CT value for 40 Hounsfield units on 70 keV monochromatic images, successfully differentiating from healthy livers and achieving the diagnosis of liver fibrosis. Furthermore, the enhancement produced by the BiF3 @PDA@HA nanoprobes in vivo increases as the monochromatic energy decreases from 70 to 40 keV, optimizing the conspicuity of the diseased areas. As a proof of concept, the strategically designed nanoprobes with energy-dependent attenuation characteristics not only expand the scope of CT application, but also hold excellent potential for precise imaging-based disease diagnosis.

Smart design of exquisite multidimensional multilayered sand-clock-like upconversion nanostructures with ultrabright luminescence as efficient luminescence probes for bioimaging application

A facile scalable approach is presented for the rational design of multidimensional, multilayered sand-clock-like UCNPs (denoted as UCCKs) bounded with high index facets, with a tunable Nd³⁺ content, and without a template or multiple complicated reaction steps. This was achieved using the seed-mediated growth and subsequent longitudinal direction epitaxial growth with the assistance of oleic acid and NH₄F. The as-formed UCCKs composed of an inner layer (NaYF₄:Yb,Er,Ca), an intermediate layer (NaYF₄:Yb,Ca), and an outer layer (NaNdF₄:Yb,Ca). The outer shell, enriched with Nd³⁺ sensitizer, augmented the near-infrared (NIR) photon absorption, whereas the intermediate shell, enriched with Yb³⁺, acted as a bridge for energy transfer from Nd³⁺ to Er³⁺ emitter in the inner core alongside with precluding any deleterious energy back-transfer from Er³⁺ or quenching effect from Nd³⁺. These unique structural and compositional properties of UCCKs endowed the UCL intensity of UCCKs by 22 and 10 times higher than that of hexagonal UCNP core (NaYF₄:Yb,Er,Ca) and hexagonal UCNP core-shell (NaYF₄:Yb,Er,Ca@NaYF₄:Yb,Ca), respectively. Intriguingly, the UCL intensity increased significantly with increasing the content of Nd³⁺ in the outer shell. The silica-coated UCCKs were used as excellent long-term luminescence probes for the in vitro bioimaging without any noteworthy cytotoxicity. The presented approach may pave the road for controlling the synthesis of multidimensional UCCKs for various applications. Graphical abstract We developed novel multidimensional multilayered sand-clock-like upconversion nanostructures composed of a spherical inner core (NaYF₄:Yb,Er,Ca), hexagonal intermediate shell (NaYF₄:Yb,Ca) and two up-down outer shell (NaNdF₄:Yb,Ca) with controllable Nd³⁺ as an efficient and safe probe for bioimaging applications without any quenching effect.

Peptide-enhanced tumor accumulation of upconversion nanoparticles for sensitive upconversion luminescence/magnetic resonance dual-mode bioimaging of colorectal tumors

Currently, it is still a great challenge to develop tumor targeting nanoparticles with high sensitivity and high resolution for improving the non-invasive detection ability of colorectal cancer (CRC) at an early stage. In this study, NaErF₄:Yb@NaGdF₄:Yb core@shell upconversion nanoparticles (UCNPs) were prepared with high upconversion luminescence (UCL) emission in red light region through adjusting the doping ratios of Er and Yb elements in the core. For biomedical applications, the carboxyl-terminated silica shell was introduced to transfer the as-prepared UCNPs from the organic phase to the aqueous phase, and allowed conjugation with peptide ligands derived from the l-SP5 peptide (i.e., l-SP5-H and l-SP5-C), respectively. Due to the tumor-targeting affinity of the PSP motif in the peptide ligands, the as-prepared peptide functionalized UCNPs (UCNP@SiO₂-l-SP5-H and UCNP@SiO₂-l-SP5-C) can be used as an active tumor targeting contrast agents for UCL/T₁-weighted magnetic resonance (MR) dual-mode imaging. Both the in vitro and in vivo experimental results demonstrated that UCNP@SiO₂-l-SP5-C has relatively high affinity for the HCT116 CRC subtype. Moreover, UCNP@SiO₂-l-SP5-C can visualize ultra-small subcutaneous xenografted HCT116 tumors (c.a. 13 mm³ in volume) by in vivo UCL imaging. STATEMENT OF SIGNIFICANCE: 1. High red emission UCNPs were synthesized for tumor-targeting dual-mode bioimaging. 2. With tumor-binding affinity peptide, UCNP@SiO₂-l-SP5-C shows high HCT116 tumor targeting ability. 3. UCNP@SiO₂-l-SP5-C successfully achieves sensitive detection of ultrasmall HCT116 tumors.

Application of Lectin Microarrays for Biomarker Discovery

Many proteins in living organisms are glycosylated. As their glycan patterns exhibit protein-, cell-, and tissue-specific heterogeneity, changes in the glycosylation levels could serve as useful indicators of various pathological and physiological states. Thus, the identification of glycoprotein biomarkers from specific changes in the glycan profiles of glycoproteins is a trending field. Lectin microarrays provide a new glycan analysis platform, which enables rapid and sensitive analysis of complex glycans without requiring the release of glycans from the protein. Recent developments in lectin microarray technology enable high-throughput analysis of glycans in complex biological samples. In this review, we will discuss the basic concepts and recent progress in lectin microarray technology, the application of lectin microarrays in biomarker discovery, and the challenges and future development of this technology. Given the tremendous technical advancements that have been made, lectin microarrays will become an indispensable tool for the discovery of glycoprotein biomarkers.

Tumor self-responsive upconversion nanomedicines for theranostic applications

To date, malignant tumors continue to be the most lethal disease, causing more than 8.2 million deaths worldwide each year. In recent years, nanostructures based on rare-earth upconversion luminescent nanoparticles have shown significant advantages in the integration of multimodal imaging and therapy. Compared with normal tissues, the tumor microenvironment (TME) exhibits unique characteristics including high interstitial fluid pressure, abnormal blood vessels, a hypoxic and slightly acidic environment, and high levels of glutathione (GSH) and hydrogen peroxide (H2O2). According to these characteristics, increasing attention in the antitumor field has been given to designing nanomedicines with specific responses to the TME based on rare-earth upconversion nanoparticles (UCNPs) and to achieving efficient tumor diagnosis and treatment under the premise of reducing side effects. Nevertheless, a review that systematically summarizes TME-responsive upconversion nanomedicines (UCNMs) for realizing tumor self-enhanced theranostics has not been published to date. In this review, we summarize the recent progress made in UCNP-based nanotherapeutics by highlighting the increasingly developing trend of TME-responsive UCNMs. The general characteristics of the TME are introduced in detail and their utilization in designing TME-responsive UCNMs is systematically discussed. Based on NIR light-excited optical imaging, we discuss the superiority of UCNMs when applied in tumor theranostics with an emphasis on how to use them to realize TME-mediated multimodal imaging-guided therapy.

Rational synthesis of three-dimensional core-double shell upconversion nanodendrites with ultrabright luminescence for bioimaging application

Herein, we rationally fabricated three-dimensional upconversion core–double shell nanodendrites as efficient and safe luminescent probes for in vitro and in vivo bioimaging.

Engineering the morphology of rare-earth doped NaYF₄-based upconversion nanoparticles (UCNPs) can effectively tune their upconversion luminescence emission (UCLE) properties. Herein, we rationally synthesized a new class of three-dimensional upconversion core–double-shell nanodendrites (UCNDs) including an active core (NaYF₄:Yb,Er,Ca) capped by a transition layer (NaYF₄:Yb,Ca) and an active outer shell (NaNdF₄:Yb,Ca). The high concentration of the Nd³⁺ sensitizer in the outer dendritic shell enhances the luminescence intensity, while the transition layer enriched with Yb³⁺ acts as an efficient energy migration network between the outer shell and inner core along with preventing the undesired quenching effects resulting from Nd³⁺. These unique structural and compositional merits enhanced the UCLE of UCNDs by 5 and 15 times relative to NaYF₄:Yb,Er,Ca@NaYF₄:Yb,Ca truncated core–shell UCNPs and NaYF₄:Yb,Er,Ca spherical core UCNPs, respectively, under excitation at 980 nm. The SiO₂–COOH layer coated UCNDs (UCND@SiO₂–COOH) were successfully used as efficient long-term luminescent probes for in vitro and in vivo bioimaging without any significant toxicity. The uptake and retention of UCND@SiO₂–COOH were mostly found in the liver and spleen. This study may open the way towards the preparation of three-dimensional UCND nanostructures for biomedical applications.

Novel oligopeptide nanoprobe for targeted cancer cell imaging

Co-assembly of WFFW tetrapeptide and RGDWFFW heptapeptide generated the photostable and fluorescence-tunable nanoprobe, which could selectively image the cancer cells.