Publikationsdatenbank

Ultrastructural morphology of organoids from head and neck squamous cell carcinomas following irradiation (2023)

Art

Vortrag

Autoren

Fisch, A. S. (WE 1)

Plendl, J. (WE 1)

Tinhofer, I.

Kongress

3rd World Congress of the European Society for Clinical Hemorheology and Microcirculation, the International Society for Clinical Hemorheology, the International Society of Biorheology

Regensburg, Bavaria, Germany, 28.09. – 30.10.2023

Quelle

Sprache

Englisch

Kontakt

Institut für Veterinär-Anatomie

Koserstr. 20
14195 Berlin
+49 30 838 75784
anatomie@vetmed.fu-berlin.de

Abstract / Zusammenfassung

Objective
Inefficient vascularization in solid tumors leads to hypoxia, a major cause of resistance to radiotherapy. The three-dimensional architecture of patient-derived organoid models (PDOs) facilitates a more representative oxygen gradient than traditional monolayer cultures. Until now, there is only sparse information about the ultrastructure of these organoids. Therefore, we examined untreated and irradiated organoids by transmission electron microscopy to investigate ultrastructural effects of irradiation.
Materials & Methods
Two patient-organoid models from head and neck squamous cell carcinoma (HNSCC) were processed for transmission electron microscopy. One of the two models was irradiated with 0, 2 and 2 x 2Gy seven days before. The same protocol was applied on the radiosensitive (C46) and intermediate radioresistant (C78) subclones derived from the HNSCC cell line FaDu. Pimonidazole was used to stain the untreated PDOs for hypoxia. Nuclei were counterstained with Hoechst on cryosections of the PDOs.
Results
The PDOs recapitulate aspects of the ultrastructural morphology of poorly differentiated squamous cell carcinoma, such as high nuclear to cytoplasmic index, segmented nuclei, well developed cell organelles and nucleoli, high abundance of polyribosomes and low content of heterochromatin. Even though, the organoids were generated from whole tumor tissue, there was no evidence for the presence of vessel like structures. One possible explanation for this is the diverting demands concerning the media composition between different cell types. The inner core of several organoid sections had a positive fluorescence signal for hypoxia. The most striking ultrastructural changes in irradiated organoids included increased number of fragmented cells, heterolysosomes, lipid droplets and membrane blebs. Upon radiation the quantity of microvilli diminished in cells showing signs of apoptosis or necrosis. In FaDu C46, those features were already detectable after a total dose of 2 Gy. The double dose was necessary to induce a comparable effect in FaDu C78.
Conclusion
Transmission electron microscopy reveals distinct ultrastructural changes and different responses to radiotherapy, opening opportunities to study personal radioresistance mechanisms in more detail. Specific culture conditions of PDOs using culture media supplemented with endothelial growth factors are under investigation.