Electrospun nanofiber scaffolds for the propagation and analysis of breast cancer stem cells in vitro

Abstract

Despite advances in cancer treatment, breast cancer remains the second foremost cause of cancer mortality among women, with a high rate of relapse after initial treatment success. A subpopulation of highly malignant cancer cells, known as cancer stem cells (CSCs), is suspected to be linked to metastasis and relapse. Targeting of CSCs may therefore provide a means of addressing cancer-related mortality. However, due to their low population in vivo and a lack of proper culture platform for their propagation, much of the CSC biology remains unknown. Since maintenance of CSCs is heavily influenced by the tumor microenvironment, this study developed a 3D culture platform that mimics the metastatic tumor extracellular matrix (ECM) to effectively increase CSC population in vitro and allow CSC analysis. Through electrospinning, nanofibers that were aligned, porous, and collagen-coated were fabricated from polycaprolactone to recreate the metastatic tumor ECM assemblage. Breast cancer cells seeded onto the nanofiber scaffolds exhibited gross morphology and cytoskeletal phenotype similar to invasive cancer cells. Moreover, the population of breast cancer stem cells increased in nanofiber scaffolds. Analysis of breast cancer cells grown on the nanofiber scaffolds demonstrated an upregulation of mesenchymal markers and an increase in cell invasiveness suggesting the cells have undergone epithelial-mesenchymal transition. These results indicate that the fabricated nanofiber scaffolds effectively mimicked the tumor microenvironment that maintains the cancer stem cell population, offering a platform to enrich and analyze CSCs in vitro.

Artificial tumor matrices and bioengineered tools for tumoroid generation

“…Materials commonly utilized to construct the scaffolds include natural polymers (such as gelatin, collagen, and chitosan-alginate), synthetic polymers (such as poly (ε-caprolactone) (PCL) and polylactic acids (PLAs), colloidal crystal poly), and bioactive ceramics (hydroxyapatite and silica) [122,123]. These materials were further used to fabricate porous scaffolds via various procedures, such as emulsion [124], electrospinning [125][126][127], solvent-casting particleleaching [127], 3D printing [128], stereolithography [129] and gas foaming [130].…”

“…Through electrospinning, Prieto et al built a 3D culture system that can mimic metastatic ECM to investigate the behavior of breast CSCs in vitro [125]. In their study, polycaprolactone (PCL)-based nanofibers were fabricated in different forms, such as aligned, porous, and collagen-coated.…”

“…At the same time, the upregulation of mesenchymal markers, including Nestin, Oct-3/4, Sox2, CD49f, and ALDH1, suggests that cancer cells have experienced epithelialmesenchymal transition. Their study provides a culture platform for maintaining CSC propagation by mimicking tumor ECM [125].…”

Developing Fibrous Biomaterials to Modulate Epithelial to Mesenchymal Transition

“…In another study, Prieto et al [2021] fabricated scaffolds from electrospinning that could replicate a tumor microenvironment that allowed them to study cancer stem cells undergoing EMT. A 18% PCL 3D scaffold was produced with particular care over diameter size due to the link between ECM diameter and cancer invasiveness.…”

Breast Cancer Cell Cultures on Electrospun Poly(ε-Caprolactone) as a Potential Tool for Preclinical Studies on Anticancer Treatments

“…Thus, thanks to their porosity, electrospun fiber meshes provide a natural 3D tissue-like structure enabling oxygen and nutrient gradients [ 11 , 12 ]. Various electrospun PCL fibrous scaffolds have been already evaluated to obtain 3D in vitro breast cancer models useful for drug screening and reducing the number of animals in cancer research [ 3 , 7 , 11 , 13 , 14 , 15 , 16 ]. Collectively, these scaffolds supported adhesion and growth of various breast cancer cell lines and, interestingly, increased stem cell population [ 13 , 14 , 15 ].…”