Membrane glycome is impacted by the cell culturing mode of neuroblastoma cells with differing migration and invasion potential.

Neuroblastoma is a highly metastatic childhood cancer for which studies indicate an association between protein glycosylation and tumor behavior. However, there is a lack of detailed glycome analysis on neuroblastoma cells that have varying metastatic potential. Furthermore, the impact of the cell culturing mode, i.e. 2-dimensional (2D) versus 3-dimensional (3D) spheroids, on the membrane protein glycome is unknown. To address these gaps in knowledge, we mapped membrane protein N- and O-glycosylation of neuroblastoma cells that have lower invasive and metastatic potential (Stathmin shRNA-expressing cells, StmnSeq2SH, and StmnSeq3SH) compared with control cells (control shRNA-expressing cells, CtrlSH). We showed that the neuroblastoma cells with different migratory and invasive potential underwent drastic changes in their membrane protein N-glycosylation exclusively when cultured in 3D spheroids. We also investigated the impact of 2D and 3D cell culture methods on cellular glycosylation using the neuroblastoma cells and found the cell N-glycome was markedly impacted by the culture method, with the 2D grown cells showing an abundance of oligomannosidic glycans, whereas 3D spheroids expressed more complex type glycans on their membrane proteins. In summary, this study provides the first comprehensive protein glycome profiling of neuroblastoma cells that have varying invasiveness and migratory potential and unravels the distinct membrane glycan features of cells that are grown under 2D versus 3D culture conditions.

Coordination of asparagine uptake and asparagine synthetase expression modulates CD8+ T cell activation.

T cell receptor (TCR) triggering by antigen results in metabolic reprogramming that, in turn, facilitates the exit of T cells from quiescence. The increased nutrient requirements of activated lymphocytes are met, in part, by upregulation of cell surface transporters and enhanced uptake of amino acids, fatty acids, and glucose from the environment. However, the role of intracellular pathways of amino acid biosynthesis in T cell activation is relatively unexplored. Asparagine is a nonessential amino acid that can be synthesized intracellularly through the glutamine-hydrolyzing enzyme asparagine synthetase (ASNS). We set out to define the requirements for uptake of extracellular asparagine and ASNS activity in CD8+ T cell activation. At early time points of activation in vitro, CD8+ T cells expressed little or no ASNS, and, as a consequence, viability and TCR-stimulated growth, activation, and metabolic reprogramming were substantially impaired under conditions of asparagine deprivation. At later time points (more than 24 hours of activation), TCR-induced mTOR-dependent signals resulted in ASNS upregulation that endowed CD8+ T cells with the capacity to function independently of extracellular asparagine. Thus, our data suggest that the coordinated upregulation of ASNS expression and uptake of extracellular asparagine is involved in optimal T cell effector responses.

A 3D Bioprinter Specifically Designed for the High-Throughput Production of Matrix-Embedded Multicellular Spheroids.

3D in vitro cancer models are important therapeutic and biological discovery tools, yet formation of matrix-embedded multicellular spheroids prepared in high-throughput (HTP), and in a highly controlled manner, remains challenging. This is important to achieve robust and statistically relevant data. Here, we developed an enabling technology consisting of a bespoke drop-on-demand 3D bioprinter capable of HTP printing of 96-well plates of spheroids. 3D multicellular spheroids are embedded inside a hydrogel matrix with precise control over size and cell number, with the intra-experiment variability of embedded spheroid diameter coefficient of variation being between 4.2% and 8.7%. Application of 3D bioprinting HTP drug screening was demonstrated with doxorubicin. Measurements of IC50 values showed sensitivity to spheroid size, embedding, and how spheroids conform to the embedding, revealing parameters shaping biological responses in these models. Our study demonstrates the potential of 3D bioprinting as a robust HTP platform to screen biological and therapeutic parameters.

Targeted Doxorubicin-Loaded Bacterially Derived Nano-Cells for the Treatment of Neuroblastoma.

Advanced stage neuroblastoma is an aggressive disease with limited treatment options for patients with drug-resistant tumors. Targeted delivery of chemotherapy for pediatric cancers offers promise to improve treatment efficacy and reduce toxicity associated with systemic chemotherapy. The EnGeneIC Dream Vector (EDVTM) is a nanocell, which can package chemotherapeutic drugs and target tumors via attachment of bispecific proteins to the surface of the nanocell. Phase I trials in adults with refractory tumors have shown an acceptable safety profile. Herein we investigated the activity of EGFR-targeted and doxorubicin-loaded EDVTM (EGFREDVTMDox) for the treatment of neuroblastoma. Two independent neuroblastoma cell lines with variable expression of EGFR protein [SK-N-BE(2), high; SH-SY-5Y, low] were used. EGFREDVTMDox induced apoptosis in these cells compared to control, doxorubicin, or non-doxorubicin loaded EGFREDVTM In three-dimensional tumor spheroids, imaging and fluorescence life-time microscopy revealed that EGFREDVTMDox had a marked enhancement of doxorubicin penetration compared to doxorubicin alone, and improved penetration compared to non-EGFR-targeted EDVTMDox, with enhanced spheroid penetration leading to increased apoptosis. In two independent orthotopic human neuroblastoma xenograft models, short-term studies (28 days) of tumor-bearing mice led to a significant decrease in tumor size in EGFREDVTMDox-treated animals compared to control, doxorubicin, or non-EGFR EDVTMDox There was increased TUNEL staining of tumors at day 28 compared to control, doxorubicin, or non-EGFR EDVTMDox Moreover, overall survival was increased in neuroblastoma mice treated with EGFREDVTMDox (P < 0007) compared to control. Drug-loaded bispecific-antibody targeted EDVsTM offer a highly promising approach for the treatment of aggressive pediatric malignancies such as neuroblastoma. Mol Cancer Ther; 17(5); 1012-23. ©2018 AACR.

Choice of Capping Group in Tripeptide Hydrogels Influences Viability in the Three-Dimensional Cell Culture of Tumor Spheroids.

Two peptide-derived low-molecular-weight gelators bearing different capping groups, 9-fluorenylmethyloxycarbonyl (Fmoc) and phenothiazine, were synthesized and their gel networks were characterized. The variation of the N-terminal capping group affects the viability of these hydrogels as a three-dimensional cell culture for multicellular tumor spheroids. These results indicate that the phenothiazine capping group is a more biocompatible alternative to the widely used Fmoc moiety.