Hassall, T. | Search bioRxiv

bioRxiv2022

Targeting OLIG2 increases therapeutic responses in SHH medulloblastoma mouse models and patient-derived medulloblastoma organoids

Recurrence after therapy is the primary life-threatening complication of medulloblastoma. In Sonic Hedgehog (SHH)-subgroup medulloblastoma, OLIG2-expressing tumour stem cells are crucial to recurrence. We investigated the potential of the small-molecule OLIG2 inhibitor CT-179 to decrease recurrence in patient-derived organoids, mice genetically-engineered to develop SHH-driven MB, and mice with MB patient-derived xenograft (PDX) tumours. We found that OLIG2 mRNA significantly correlated with poor survival in patients with SHH-MB, but not other subgroups. CT-179 rapidly downregulated OLIG2 protein in vitro and displayed nanomolar IC50 values. CT-179 arrested MB cells at G2/M, with degradation of cyclin B1 and phospho-CDK1 inducing apoptosis. In vivo CT-179 induced similar cell cycle changes in MBs in Smo-mutant mice and significantly increased mouse survival. In both MB organoids and mouse models, CT-179 combined with radiotherapy showed greater efficacy than either treatment alone. These data highlight the potential for OLIG2-targeted therapy to improve MB outcomes by targeting recurrent disease.

cancer biology↗

bioRxiv2020

Germline ERBB3 mutation in familial non-small cell lung carcinoma: expanding the role of the ErbB family in oncogenesis.

BackgroundLung cancer is the commonest cause of cancer deaths worldwide. Although strongly associated with smoking, predisposition to lung cancer is also heritable with multiple common risk variants identified. Rarely, dominantly inherited non-small-cell lung cancer (NSCLC) has been reported due to somatic mutations in EGFR/ErbB1 and ERBB2. MethodsGermline exome sequencing was performed in a multi-generation family with autosomal dominant NSCLC, including an affected child. Tumour samples were also sequenced. Full-length wild-type (wtErbB3) and mutant ERBB3 (mutErbB3) constructs were transfected into HeLa cells. Protein expression, stability, and sub-cellular localisation were assessed; and cellular proliferation, pAkt/Akt, and pERK levels were determined. ResultsA novel germline variant in ERBB3 (c.1946T>G: p.Iso649Arg), coding for receptor tyrosineprotein kinase erbB-3 (ErbB3), was identified, with appropriate segregation. There was no loss-of-heterozygosity in tumour samples. Both wtErbB3 and mutErbB3 were stably expressed. MutErbB3-transfected cells demonstrated an increased ratio of the 80kD form (which enhances proliferation) compared to the full-length (180kD) form. MutErbB3 and wtErbB3 had similar punctate cytoplasmic localisation pre- and post-EGF stimulation; however, EGFR levels decreased faster post-stimulation in mutErbB3-transfected cells, suggesting more rapid processing of the mutErbB3/EGFR heterodimer. Cellular proliferation was increased in mutErbB3-transfected cells compared to wtErbB3 transfection. MutErbB3-transfected cells also showed decreased pAkt/tAkt ratios and increased pERK/tERK 30 minutes post-stimulation compared to wtErbB3 transfection, demonstrating altered signalling pathway activation by mutErbB3. Cumulatively, these results support this mutation as tumorogenic. ConclusionsThis is the first reported family with a germline ERBB3 mutation causing heritable NSCLC, furthering understanding of the ErbB family pathway in oncogenesis.

genomics↗