A Fully Synthetic Glycopeptide Antitumor Vaccine Based on Multiple Antigen Presentation on a Hyperbranched Polymer

For antitumor vaccines both the selected tumor‐associated antigen, as well as the mode of its presentation, affect the immune response. According to the principle of multiple antigen presentation, a tumor‐associated MUC1 glycopeptide combined with the immunostimulating T‐cell epitope P2 from tetanus toxoid was coupled to a multi‐functionalized hyperbranched polyglycerol by “click chemistry”. This globular polymeric carrier has a flexible dendrimer‐like structure, which allows optimal antigen presentation to the immune system. The resulting fully synthetic vaccine induced strong immune responses in mice and IgG antibodies recognizing human breast‐cancer cells.     

A Fully Synthetic Four‐Component Antitumor Vaccine Consisting of a Mucin Glycopeptide Antigen Combined with Three Different T‐Helper‐Cell Epitopes

In a new concept of fully synthetic vaccines, the role of T‐helper cells is emphasized. Here, a synthetic antitumor vaccine consisting of a diglycosylated tumor‐associated MUC1 glycopeptide as the B‐cell epitope was covalently cross‐linked with three different T‐helper‐cell epitopes via squaric acid ligation of two linear (glyco)peptides. In mice this four‐component vaccine administered without external immune‐stimulating promoters elicit titers of MUC1‐specific antibodies that were about eight times higher than those induced by a vaccine containing only one T‐helper‐cell epitope. The promising results indicate that multiple activation of different T‐helper cells is useful for applications in which increased immunogenicity is required. In personalized medicine, in particular, this flexible construction of a vaccine can serve as a role model, for example, when T‐helper‐cell epitopes are needed that match human leukocyte antigens (HLA) in different patients.     

Fast Epitope Mapping for the Anti‐MUC1 Monoclonal Antibody by Combining a One‐Bead‐One‐Glycopeptide Library and a Microarray Platform

Anti‐MUC1 monoclonal antibodies (mAbs) are powerful tools that can be used to recognize cancer‐related MUC1 molecules, the O‐glycosylation status of which is believed to affect binding affinity. We demonstrate the feasibility of using a rapid screening methodology to elucidate those effects. The approach involves i) “one‐bead‐one‐compound”‐based preparation of bilayer resins carrying glycopeptides on the shell and mass‐tag tripeptides coding O‐glycan patterns in the core, ii) on‐resin screening with an anti‐MUC1 mAb, iii) separating positive resins by utilizing secondary antibody conjugation with magnetic beads, and (iv) decoding the mass‐tag that is detached from the positive resins pool by using mass spectrometric analysis. We tested a small library consisting of 27 MUC1 glycopeptides with different O‐glycosylations against anti‐MUC1 mAb clone VU‐3C6. Qualitative mass‐tag analysis showed that increasing the number of glycans leads to an increase in the binding affinity. Six glycopeptides selected from the library were validated by using a microarray‐based assay. Our screening provides valuable information on O‐glycosylations of epitopes leading to high affinity with mAb.     

DNA Nanolithography Enables a Highly Ordered Recognition Interface in a Microfluidic Chip for the Efficient Capture and Release of Circulating Tumor Cells

Microfluidic chips with nano‐scale structures have shown great potential, but the fabrication and cost issues restrict their application. Herein, we propose a conceptually new “DNA nanolithography in a microfluidic chip” by using sub‐10 nm three‐dimensional DNA structures (TDNs) as frameworks with a pendant aptamer at the top vertex (ApTDN‐Chip). The nano‐scale framework ensures that the aptamer is in a highly ordered upright orientation, avoiding the undesired orientation or crowding effects caused by conventional microfluidic interface fabrication processes. Compared with a monovalent aptamer modified chip, the capture efficiency of ApTDN‐Chip was enhanced nearly 60 % due to the highly precise dimension and rigid framework of TDNs. In addition, the scaffolds make DNase I more accessible to the aptamer with up to 83 % release efficiency and 91 % cell viability, which is fully compatible with downstream molecular analysis. Overall, this strategy provides a novel perspective on engineering nano‐scaffolds to achieve a more ordered nano‐topography of microfluidic chips.     

Disposable Amperometric Immunosensor for the Determination of the E‐Cadherin Tumor Suppressor Protein in Cancer Cells and Human Tissues

This paper describes the results obtained in the development of the first electrochemical immunosensor described to date for the detection of E‐cadherin (E‐cad) protein, a relevant biomarker of prognosis and metastasis in cancer, based on the use of magnetic microcarriers (MBs) and amperometric transduction at screen‐printed carbon electrodes (SPCEs). Thus, the determination of E‐cad protein involved the use of two specific antibodies against this protein (one of them labelled with HRP) in a sandwich configuration onto HOOC‐MBs. The magnetic bioconjugates were captured onto SPCEs and the amperometric transduction was performed using the H₂O₂/hydroquinone (HQ) system. Under optimal conditions, this bioplatform demonstrated a wide linear concentration range (0.50–25 ng mL^?1) and a detection limit as low as 0.16 ng mL^?1, well below the optimal cut‐off level for the E‐cad protein (defined as 10,000 ng mL^?1 for soluble E‐cad levels in serum). The developed sensor also showed a good reproducibility among measurements with seven different sensors constructed in the same manner (RSD, 5.4 %), stability for more than 15 days and good specificity towards other proteins commonly found on biological samples. The applicability of this simple handling bioplatform for the direct determination of this protein in cell lysates with different metastatic potential and extracts from paraffined‐embedded human colorectal cancer tissues of different grade were also demonstrated.     

Broussochalcone A Is a Novel Inhibitor of the Orphan Nuclear Receptor NR4A1 and Induces Apoptosis in Pancreatic Cancer Cells

The orphan nuclear receptor 4A1 (NR4A1) is overexpressed in pancreatic cancer and exhibits pro-oncogenic activity, and NR4A1 silencing and treatment with its inactivators has been shown to inhibit pancreatic cancer cells and tumor growth. In this study, we identified broussochalcone A (BCA) as a new NR4A1 inhibitor and demonstrated that BCA inhibits cell growth partly by inducing NR4A1-mediated apoptotic pathways in human pancreatic cancer cells. BCA downregulated specificity protein 1 (Sp1)-mediated expression of an anti-apoptotic protein, survivin, and activated the endoplasmic reticulum (ER) stress-mediated apoptotic pathway. These results suggest that NR4A1 inactivation contributes to the anticancer effects of BCA, and that BCA represents a potential anticancer agent targeting NR4A1 that is overexpressed in many types of human cancers.     

Actinolactomycin,a New 2-Oxonanonoidal Antitumor Antibiotic Produced by Streptomyces flavoretus 18522,and its Inhibitory Effect on the Proliferation of Human Cancer Cells

In the course of our screening for new anticancer agents from microbial resources usingmammalian cancer tsFT210 cells1-3, we found that the fermentation broth of anactinomycete strain 18522 significantly inhibited the cell cycle of tsFT210 cells at theG0/G1 phase. From the fermentation broth of this strain, we have now isolated a new2-oxonanonoidal anitumor antibiotic, named actinolactomycin 1, through a bioassay-guided separation procedure. In this communication, the isolation, structure de…     

In Situ Synthesis of an Aptamer‐Based Polyvalent Antibody Mimic on the Cell Surface for Enhanced Interactions between Immune and Cancer Cells

An ability to promote therapeutic immune cells to recognize cancer cells is important for the success of cell‐based cancer immunotherapy. We present a synthetic method for functionalizing the surface of natural killer (NK) cells with a supramolecular aptamer‐based polyvalent antibody mimic (PAM). The PAM is synthesized on the cell surface through nucleic acid assembly and hybridization. The data show that PAM has superiority over its monovalent counterpart in powering NKs to bind to cancer cells, and that PAM‐engineered NK cells exhibit the capability of killing cancer cells more effectively. Notably, aptamers can, in principle, be discovered against any cell receptors; moreover, the aptamers can be replaced by any other ligands when developing a PAM. Thus, this work has successfully demonstrated a technology platform for promoting interactions between immune and cancer cells.