DRES-09. IN VIVO FUNCTIONAL GENOMICS IDENTIFIES DRIVERS OF CHEMORESISTANCE IN MEDULLOBLASTOMA. (5th November 2018)

• Record Type: Journal Article
• Authors: Guerreiro Stücklin, Ana; Garzia, Livia; Skowron, Patryk; De Antonellis, Pasqualino; Nör, Carolina; Wu, Xiaochong; Taylor, Michael
• Is Part Of: Neuro-oncology. Volume 20(2018)Supplement 6
• Page Start: vi77
• Page End: vi77
• Publication Date: 2018-11-05
• Subjects: Brain Neoplasms -- Periodicals; Brain -- Tumors -- Periodicals; Brain -- Cancer -- Periodicals; Nervous system -- Cancer -- Periodicals; 616.99481
• DOI: 10.1093/neuonc/noy148.316
• Languages: English
• ISSNs: 1522-8517

Abstract

Abstract: Brain tumours are the main cause of cancer-related death during childhood and medulloblastoma an aggressive embryonal tumour that arises in the posterior fossa – is the most common malignant tumour in this age group. Chemotherapy is a cornerstone of the postsurgical treatment, particularly in younger children in whom craniospinal irradiation is omitted due to the devastating side effects in the developing brain. Medulloblastoma often progresses or recurs after chemotherapy with a dismal prognosis. We used the Sleeping Beauty (SB) transposon-driven Ptch+/−/Math1-SB11/T2Onc sonic hedgehog (SHH) medulloblastoma murine model as a functional genomic tool to perform a genome-wide screen and identify genes and pathways that promote resistance to chemotherapy. After sub-total resection of the primary tumours, the mice were treated with repeated cycles of chemotherapy (cisplatin 5 mg/kg IP once on day 1 followed by cyclophosphamide 150 mg/kg IP daily from day 2 – 5) every 2 weeks for up to 3 cycles and monitored for tumour recurrence. The primary tumours (pre-treatment) and the tumours and metastasis that regrew after chemotherapy were deep sequenced to determine the transposon insertion sites. We identified recurrence-specific clonally selected insertions that promoted tumour growth despite therapy, including p53 (recurrently mutated in human tumours at relapse) and several other genes involved in DNA repair. Using cerebellar orthotopic models of p53-mutated SHH medulloblastoma, we observed a significant improvement in survival when the ATM inhibitor AZ32 was added to the chemotherapy backbone. This provides a rationale for developing therapeutic approaches targeting DNA repair in combination with conventional chemotherapy to prevent chemoresistance and medulloblastoma recurrence.