Mechanical Property of Hydrogels and the Presence of Adipose Stem Cells in Tumor Stroma Affect Spheroid Formation in the 3D Osteosarcoma Model

Abstract

Osteosarcoma is one of the most common metastatic bone cancers, which results in significant morbidity and mortality. Unfolding of effectual therapeutic strategies against osteosarcoma is impeded because of the absence of adequate animal models, which can truly recapitulate disease biology of humans. Tissue engineering provides an opportunity to develop physiologically relevant, reproducible, and tunable in vitro platforms to investigate the interactions of osteosarcoma cells with its microenvironment. Adipose-derived stem cells (ASCs) are detected adjacent to osteosarcoma masses and are considered to have protumor effects. Hence, the present study focuses on investigating the role of reactive ASCs in formation of spheroids of osteosarcoma cells (Saos 2) within a three-dimensional (3D) niche, which is created using gellan gum (GG)−silk fibroin. By modifying the blending ratio of GG−silk, the optimum stiffness of the resultant hydrogels such as GG and GG75: S25 is obtained for cancer spheroid formation. This work indicates that the co-existence of cancer and stem cells can form a spheroid, the hallmark of cancer, only in particular microenvironment stiffness. The incorporation of fibrillar silk fibroin within the hydrophilic network of GG in GG75: S25 spongy-like hydrogels closely mimics the stiffness of commercially established cancer biomaterials (e.g., Matrigel, HyStem). The GG75: S25 hydrogel maintains the metabolically active construct for a longer time with elevated expression of osteopontin, osteocalcin, RUNX 2, and bone sialoprotein genes, the biomarkers of osteosarcoma, compared to GG. The GG75: S25 construct also exhibits intense alkaline phosphatase expression in immunohistochemistry compared to GG, indicating itspotentiality to serve as biomimetic niche to model osteosarcoma. Taken together, the GG−silk fibroin-blended spongy-like hydrogel is envisioned as an alternative low-cost platform for 3D cancer modeling.

Mechanical properties of cell- and microgel bead-laden oxidized alginate-gelatin hydrogels

“…Synthetic hydrogels such as polyethylene glycol (PEG), 3 2-hydroxyethyl methacrylate (HEMA)-based hydrogels, 4 poly(oxazoline)s (POx), 5 or polyacrylamide (PAAm), as well as naturally derived hydrogels such as alginate, gelatin, collagen, or fibrin matrices, [6][7][8][9] have been used in various biomedical appli-cations. 1 Frequently, these include the delivery of cells, [10][11][12][13][14] growth factors, [15][16][17] or drugs, [18][19][20][21][22] in vitro tissue and tumor models, [23][24][25] and tissue engineering (TE) matrices. 2,[26][27][28][29][30] The role of biopolymer hydrogels in TE is to chemically and physically mimic the extracellular matrix (ECM) environment to facilitate controlled cell adhesion, proliferation, differentiation, and matrix remodeling.…”

Extent and characteristics of immune infiltration in clear cell renal cell carcinoma and the prognostic value

“…Therefore, the tumor tissue is more appropriate to be treated as an organ but not a mass of transformed epithelial cells (1)(2)(3). More and more researchers have been investigating into tumor microenvironment and gained more and more achievement revealing the effect of tumor micro-environment on various kinds of cancers (4,5). Yoshihara et al developed a new algorithm that can infer tumor cellularity using transcriptional profiles of cancer samples and it can estimate the relative amount of the stromal and immune cells that form the main non-tumor components by outputting ESTIMATE score as well as Stromal score and Immune score (6).…”

Scaffold-based 3D cellular models mimicking the heterogeneity of osteosarcoma stem cell niche

“…3, 4, 5, 6). It is well established that the presence of a bioactive 3D environment provides a higher stimulation of genes compared to a simple inducing medium, assuming high relevance for the reproduction of an in vitro more closely predictive osteosarcoma model 58,59 . In fact, many studies reported how the use of conventional 2D approaches failed to explain tumour cell biology, because they did not mimic real macrostructure, complexity (tumourstroma interactions) and heterogeneity of the tumour microenvironment 28,60 .…”