MCF7 Spheroid Development: New Insight about Spatio/Temporal Arrangements of TNTs, Amyloid Fibrils, Cell Connections, and Cellular Bridges

• Published in: International journal of molecular sciences Vol. 21; no. 15; p. 5400
• Main Authors: Pulze, Laura, Congiu, Terenzio, Brevini, Tiziana A L, Grimaldi, Annalisa, Tettamanti, Gianluca, D'Antona, Paola, Baranzini, Nicolò, Acquati, Francesco, Ferraro, Federico, de Eguileor, Magda
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 29-07-2020; MDPI
• Subjects: Acetylcysteine; Acetylcysteine - pharmacology; Adenocarcinoma; Amyloid; Amyloid - chemistry; Amyloid - drug effects; Amyloid - metabolism; amyloid fibrils; Amyloidogenesis; Biomarkers, Tumor - genetics; Biomarkers, Tumor - metabolism; Breast; Cancer; Cell Aggregation - drug effects; Cell culture; Communication; Complexity; Connexin 43 - genetics; Connexin 43 - metabolism; Cytoplasm; cytoplasmic bridges; Drug resistance; Embryogenesis; Endopeptidases; Fibrils; Free Radical Scavengers - pharmacology; Gap junctions; Gap Junctions - drug effects; Gap Junctions - metabolism; Gap Junctions - ultrastructure; Gene Expression; gp100 Melanoma Antigen - genetics; gp100 Melanoma Antigen - metabolism; Homeostasis; Homeostasis - drug effects; Homeostasis - genetics; Humans; Interleukin-18 - genetics; Interleukin-18 - metabolism; MCF-7 Cells; MCF7 3D spheroid; Morphology; Neprilysin; Neprilysin - pharmacology; Organogenesis; Oxidation-Reduction; Phenotype; Phenotypes; Phenotypic variations; Proteins; Proteolysis; Reactive Oxygen Species - antagonists & inhibitors; Reactive Oxygen Species - metabolism; ROS scavenger; Scanning electron microscopy; SOXB1 Transcription Factors - genetics; SOXB1 Transcription Factors - metabolism; Spheroids; Spheroids, Cellular - drug effects; Spheroids, Cellular - metabolism; Spheroids, Cellular - ultrastructure; Stage-Specific Embryonic Antigens - genetics; Stage-Specific Embryonic Antigens - metabolism; TNTs; Transcription Factors - genetics; Transcription Factors - metabolism; Tumors; gap junctions; MCF7 3D spheroid; amyloid fibrils; ROS scavenger; NEP treatment; cytoplasmic bridges; TNTs
• ISSN: 1422-0067; 1661-6596; 1422-0067
• DOI: 10.3390/ijms21155400

Human breast adenocarcinoma cells (MCF7) grow in three-dimensional culture as spheroids that represent the structural complexity of avascular tumors. Therefore, spheroids offer a powerful tool for studying cancer development, aggressiveness, and drug resistance. Notwithstanding the large amount of data regarding the formation of MCF7 spheroids, a detailed description of the morpho-functional changes during their aggregation and maturation is still lacking. In this study, in addition to the already established role of gap junctions, we show evidence of tunneling nanotube (TNT) formation, amyloid fibril production, and opening of large stable cellular bridges, thus reporting the sequential events leading to MCF7 spheroid formation. The variation in cell phenotypes, sustained by dynamic expression of multiple proteins, leads to complex networking among cells similar to the sequence of morphogenetic steps occurring in embryogenesis/organogenesis. On the basis of the observation that early events in spheroid formation are strictly linked to the redox homeostasis, which in turn regulate amyloidogenesis, we show that the administration of
-acetyl-l-cysteine (NAC), a reactive oxygen species (ROS) scavenger that reduces the capability of cells to produce amyloid fibrils, significantly affects their ability to aggregate. Moreover, cells aggregation events, which exploit the intrinsic adhesiveness of amyloid fibrils, significantly decrease following the administration during the early aggregation phase of neutral endopeptidase (NEP), an amyloid degrading enzyme.