A three-dimensional organoid model recapitulates tumorigenic aspects and drug responses of advanced human retinoblastoma

Abstract

Persistent or recurrent retinoblastoma (RB) is associated with the presence of vitreous or/and subretinal seeds in advanced RB and represents a major cause of therapeutic failure. This necessitates the development of novel therapies and thus requires a model of advanced RB for testing candidate therapeutics. To this aim, we established and characterized a three-dimensional, self-organizing organoid model derived from chemotherapy-naïve tumors. The responses of organoids to drugs were determined and compared to relate organoid model to advanced RB, in terms of drug sensitivities. We found that organoids had histological features resembling retinal tumors and seeds and retained DNA copy-number alterations as well as gene and protein expression of the parental tissue. Cone signal circuitry (M/L+ cells) and glial tumor microenvironment (GFAP+ cells) were primarily present in organoids. Topotecan alone or the combined drug regimen of topotecan and melphalan effectively targeted proliferative tumor cones (RXRγ+ Ki67+) in organoids after 24-h drug exposure, blocking mitotic entry. In contrast, methotrexate showed the least efficacy against tumor cells. The drug responses of organoids were consistent with those of tumor cells in advanced disease. Patient-derived organoids enable the creation of a faithful model to use in examining novel therapeutics for RB.

Retinoblastoma: Etiology, Modeling, and Treatment

“…However, tumor cells stained for rod markers are almost absent [ 46 ] in contrast to abundant numbers of cone-like cells in human retinoblastoma. Accordingly, pure tumors are defined by low expression of rod-enriched genes and high expression of cone-enriched genes compared with the normal retina [ 43 , 44 , 45 , 47 , 48 ]. Functional annotation of the gene expression profile of retinoblastoma versus the normal retina identifies genes associated with cell cycle progression, DNA replication and repair, growth and proliferation, and cell death [ 43 , 47 , 49 ].…”

Endothelial PAI-1 (Plasminogen Activator Inhibitor-1) Blocks the Intrinsic Pathway of Coagulation, Inducing the Clearance and Degradation of FXIa (Activated Factor XI)

“…14,15 Organoids capture many of the genomic variations present in solid tumors and serve as preclinical drug-screening tumor models, shown to correlate with clinical response to common cancer therapeutics. 14,15 Long-term culture is still challenging due to insufficient nutrient and oxygen supply at the core, yet attempts at vascularization are being investigated to enhance cell maturation and model longevity. 16 Alternatively, spheroids are cell aggregates used to study invasion and migration (Fig.…”

“…For example, patient-derived organoids can serve as effective preclinical models for rapidly assessing therapeutics, shown to exhibit similar responses to chemotherapeutic drugs such as topotecan and melphalan consistent with clinical outcomes. 14,15 As microfabrication techniques and biomaterials advance, models are gaining the ability to recapitulate multiple tissuespecific microenvironments connected in a physiologically relevant manner as pioneered primarily for pharmaceutical toxicity studies. Adaptation of these systems to simulate key elements of multiple metastatic stages in sequence could provide novel insight.…”

High-resolution positron emission microscopy of patient-derived tumor organoids

“…Patient-derived tumor organoids are miniature, three-dimensional, self-organized tissue culture models that are derived from primary patient tumor cells and studied in the laboratory 1,2 . These organoid cultures closely recapitulate the genetic and morphological heterogeneity of solid tumors and stromal components present in the original tumor [1][2][3][4][5][6][7][8][9][10] . They also retain the immune microenvironment of solid tumors, including the T cell receptor repertoire and PD-1/PD-L1dependent immune checkpoint status 5 .…”