TMOD-16. ZUCLOPENTHIXOL REDUCES ACTIVITY-DEPENDENT GLIOBLASTOMA PROLIFERATION

Abstract A major challenge in modeling glioblastoma in the laboratory is the complex microenvironment in which tumors evolve in humans. The varied architecture and immune privilege of the brain limits the external validity of many experiments performed in modern cell biology laboratories. Organotypic human cortical slices present an opportunity to model glioblastoma and test the effect of drugs against glioma in ex-vivo human tissue. Cortical slice cultures maintain the cellular organization of the human brain, more closely approximating glioblastoma proliferation in patients. In this study, we test the effect zuclopenthixol, a repurposed antipsychotic inhibitor of glioblastoma-induced neuronal hyperexcitability, on the proliferation of glioblastoma cells in an organotypic human cortical slice culture. Primary patient-derived glioblastoma cultures were established, and human cortical tissues were emersed in oxygenated ACSF agarose gel before preparing 250 µm thick slices. Slices were either exogenously seeded with glioblastoma cells or stained for endogenous tumor infiltration. Slices with either endogenous or exogenous seeding were then treated with zuclopenthixol or regular media change and cultured for 10 days. Proliferation was measured with Ki67 staining and quantified via automated pixel summation using the Pillow library in Python. 0.1 µM zuclopenthixol treated slices had significantly lower proliferation index in both the endogenous tumor condition (0.04 vs 0.30, P < 0.05) and the exogenous seeding condition (0.0013 vs 0.028, P = 0.033). Reduced tissue integrity was observed beginning day 8 of culture, as tissue surrounding tumor seeding sites eroded. Here, we model glioblastoma proliferation in live human tissue and quantify the anti-proliferative effect of zuclopenthixol. We show that zuclopenthixol treatment significantly reduced the proliferation index. Our experimental model allowed the optimization of organotypic human cortical slice cultures for immunofluorescence studies and live-cell imaging.