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Hydrogels composed of extracellular matrix (ECM) have been used as a substrate for 3D organoid culture, and in numerous preclinical and clinical applications to facilitate repair and reconstruction of a variety of tissues. However, these ECM hydrogel materials are fabricated using lengthy methods that have focused on enzymatic digestion of the ECM with an acid protease in an acidic solution; or the use of chaotropic extraction buffers and dialysis procedures which can affect native protein structure and function. Herein we report a method to prepare hydrogels from ECM bioscaffolds using ultrasonic cavitation. The solubilized ECM can be induced to rapidly self-assemble into a gel by adjusting temperature, and the material properties of the gel can be tailored by adjusting ECM concentration and sonication parameters. The present study shows that ECM bioscaffolds can be successfully solubilized without enzymatic digestion and induced to repolymerize into a gel form capable of supporting cell growth. STATEMENT OF SIGNIFICANCE: ECM hydrogels have been used in numerous preclinical studies to facilitate repair of tissue following injury. However, there has been relatively little advancement in manufacturing techniques, thereby impeding progress in advancing this technology toward the clinic. Laboratory techniques for producing ECM hydrogels have focused on protease digestion methods, which require lengthy incubation times. The significance of this work lies in the development of a fundamentally different approach whereby an ECM hydrogel is rapidly formed without the need for acidic solutions or protease digestion. The ultrasonic cavitation method described herein represents a marked improvement in rheological properties and processing time over traditional enzymatic methods, and may lend itself as a platform for large-scale manufacturing of ECM hydrogels.

Extracellular matrix (ECsM) bioscaffolds have been successfully used to treat five esophageal adenocarcinoma (EAC) patients following resection of neoplastic mucosal tissue. The present study evaluated the in vitro effect of ECM harvested from nonmalignant, decellularized tissue on EAC cell phenotype to understand the molecular mechanisms underlying the clinical findings. Nonmalignant (Het-1A), metaplastic (CP-A), and neoplastic (SK-GT-4, OE33) esophageal epithelial cells were exposed to ECM degradation products (250 μg/mL) prepared from heterologous urinary bladder tissue or homologous esophageal mucosa tissue, and evaluated for cell morphology, cell function, and EAC signaling pathways. Both the ECM sources downregulated neoplastic cell phenotype, but had distinctive tissue-specific effects. Urinary bladder ECM decreased OE33 and SK-GT-4 metabolism and increased CP-A apoptosis. Esophageal ECM decreased SK-GT-4, CP-A, and Het-1A proliferation; robustly downregulated PI3K-Akt-mTOR, cell cycle/DNA replication signaling, and upregulated autophagy signaling in OE33 cells; and increased cell cycle/DNA replication signaling in Het-1A cells. Both ECM sources decreased OE33 proliferation and phosphorylated AKT in OE33 cells, and in contrast, increased phosphorylated AKT in Het-1A cells. The results support the concept that the biochemical signals in nonmalignant ECM can downregulate neoplastic cell phenotype with minimal, and sometimes opposite, effects on normal cells. PI3K-Akt signaling has been implicated in EAC progression and these ECM-mediated effects may be favorable for an esophageal therapy following cancer resection. IMPACT STATEMENT: Extracellular matrix (ECM) biomaterials were used to treat esophageal cancer patients after cancer resection and promoted regrowth of normal mucosa without recurrence of cancer. The present study investigates the mechanisms by which these materials were successful to prevent the cancerous phenotype. ECM downregulated neoplastic esophageal cell function (proliferation, metabolism), but normal esophageal epithelial cells were unaffected in vitro, and suggests a molecular basis (downregulation of PI3K-Akt, cell cycle) for the promising clinical results. The therapeutic effect appeared to be enhanced using homologous esophageal ECM. This study suggests that ECM can be further investigated to treat cancer patients after resection or in combination with targeted therapy.

The use of cell secreted factors in clinical settings could be an alternative to conventional cell therapy, with the advantage of limiting concerns generally associated with traditional cell transplantation, such as tumorigenicity, immunoreactivity, and carrying of infections. Based on our published data, we predict a potential role for extracellular vesicles (EVs) in contributing to the proangiogenic activity of human fetal dermal cell secretome. Depletion of nanosized EVs from secretome significantly impaired its ability to induce formation of mesh-like structures in vitro. The isolated EVs were characterized for size and concentration by nanoparticle tracking analysis, and for protein markers (Rab5+, Alix+, CD63+, and calnexin-). The microRNA profile of EVs revealed 87 microRNAs significantly upregulated (≥15-fold increase) in fetal compared to adult dermal cell-derived EVs. Interestingly, these upregulated microRNAs included microRNAs with a validated role in angiogenesis according to literature. Moreover, the DIANA-TarBase v7.0 analysis confirmed enrichment in the KEGG signaling pathways associated with angiogenesis and wound healing, with the identification of putative target genes including thrombospondin 1. To validate the in silico data, EVs were also characterized for total protein contents. When tested in in vitro angiogenesis, fetal dermal cell-derived EVs were more effective than their adult counterpart in inducing formation of complete mesh-like structures. Furthermore, treatment of fibroblasts with fetal dermal-derived EVs determined a 4-fold increase of thrombospondin 1 protein amounts compared with the untreated fibroblasts. Finally, visualization of CSFE-labeled EVs in the cytosol of target cells suggested a successful uptake of these particles at 4-8 hours of incubation. We conclude that EVs are important contributors of the proangiogenic effect of fetal dermal cell secretome. Hence, EVs could also serve as vehicle for a successful delivery of microRNAs or other molecules of therapeutic interest to target cells.