gms | German Medical Science

Objective: Cancer-derived organoids (CDOs) are novel, complex three-dimensional ex vivo tissue cultures that accurately reflect genotype and phenotype of the original tumor with preserved cellular heterogeneity and structural architecture. They offer a new and exciting platform for studying cancer biology and developing personalized therapies. The aim of our study was to establish CDOs from meningioma (MGM) and using them as a novel platform for large-scale drug screening in a patient-individual manner.

Methods: CDOs were established by controlled reaggregation of freshly prepared single cell suspensions of MGM tissue samples in non-adhesive 96-well plates. Size and shape were continuously monitored by light microscopy. Morphology was assessed by H&E stainings. Live/dead (Invitrogen) staining was used to control integrity of CDOs. CDOs were treated with drug concentrations ranging from 10 nM to 30 µM and viability was assessed with CellTiterGlo3D (Promega).

Results: This workflow allowed us to generate several hundred mini tumors from one sample equal in size. CDOs reaggregated within 3 days by a considerable contraction of cellular mass. Thereafter, CDO diameter remained stable throughout a 14 days observation period. CDOs consisted of largely viable cells, whereas dead cells were predominantly found outside of the organoid. On H&E stainings, CDOs recapitulated the tissue of origin. As a next step, we queried if CDOs may be suitable for large-scale drug testing. First, we excluded that drug responses depend on CDO size and then used a standardised number of 25.000 cells/CDO for further experiments allowing an appropriate representation of low abundance cell types such as T-cells. As a next step, nine highly potent compounds, derived from a drug screening on MGM cell lines, were tested on CDOs. When treating CDOs generated from 35 MGM patients including three grade II and two grade III MGMs, especially the experimental MELK inhibitor OTSSP167 and the FDA-approved HDAC inhibitor Panobinostat were highly effective in most of the CDOs at the lowest tested concentration of 10 nM.

Conclusion: Taken together, we developed cancer-derived organoids from MGM reflecting accurately the original phenotype and applied them in the frame of a novel drug testing platform. Thereby, we identified Panobinostat and OTSSP167 as highly potent drugs for the treatment of aggressive meningioma.