EXTH-57. HIGH CONTENT SCREENING OF PATIENT-DERIVED CELL LINES HIGHLIGHTS THE POTENTIAL OF NON-STANDARD CHEMOTHERAPEUTIC AGENTS FOR THE TREATMENT OF RECURRENT GLIOBLASTOMA Free

Glioblastoma Multiforme (GBM) is the most common primary brain tumor in adults, yet survival outcomes remain poor. First line treatment is well established but with disease recurrence almost inevitable, improving prognosis is challenging. With the aim of personalising therapy at recurrence we have established a high content screening (HCS) platform to analyse the sensitivity profile of seven patient-derived cancer stem cell lines to 82 FDA-approved chemotherapy drugs, with and without irradiation.

Seven cancer stem cell lines were derived from patients with GBM, or GBM variants. Along with the established cell line U87-MG, each patient-derived line was cultured in tandem in serum-free conditions as adherent monolayers and three-dimensional neurospheres. Chemotherapeutics were screened at multiple concentrations and cells double-stained to observe their effect on both cell death and proliferation. Sensitivity was classified using high-throughput algorithmic image analysis.

Cell line specific drug responses were observed across the seven patient-derived cell lines. Few agents were seen to have radio-sensitising effects, yet some drug classes showed a marked difference in efficacy between monolayers and neurospheres. In vivo validation of six drugs in a U87 subcutaneous flank model indicated that a three-dimensional culture scenario more effectively predicts chemosensitivity of patient-derived GBM lines. Mitoxantrone, a type II topoisomerase inhibitor, was the most successful drug tested, inhibiting tumor growth by an average of 86.69% when compared to control (p = <0.0001). Bortezomib and Actinomycin D also significantly inhibited growth by 69.63% and 60.37% respectively (p = <0.0001).

The study puts forward a number of non-standard chemotherapeutics that could be useful in the treatment of recurrent GBM, whilst demonstrating the potential of HCS to be used for personalised treatment based on the chemosensitivity profile of patient tumor cells.