Browsing by Author "Conces, Madison L."

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    A large microRNA cluster on chromosome 19 is a transcriptional hallmark of WHO type A and AB thymomas
    (SpringerNature, 2016-02-16) Radovich, Milan; Solzak, Jeffrey P.; Hancock, Bradley A.; Conces, Madison L.; Atale, Rutuja; Porter, Ryan F.; Zhu, Jin; Glasscock, Jarret; Kesler, Kenneth A.; Badve, Sunil S.; Schneider, Bryan P.; Loehrer, Patrick J.; Department of Surgery, IU School of Medicine
    BACKGROUND: Thymomas are one of the most rarely diagnosed malignancies. To better understand its biology and to identify therapeutic targets, we performed next-generation RNA sequencing. METHODS: The RNA was sequenced from 13 thymic malignancies and 3 normal thymus glands. Validation of microRNA expression was performed on a separate set of 35 thymic malignancies. For cell-based studies, a thymoma cell line was used. RESULTS: Hierarchical clustering revealed 100% concordance between gene expression clusters and WHO subtype. A substantial differentiator was a large microRNA cluster on chr19q13.42 that was significantly overexpressed in all A and AB tumours and whose expression was virtually absent in the other thymomas and normal tissues. Overexpression of this microRNA cluster activates the PI3K/AKT/mTOR pathway. Treatment of a thymoma AB cell line with a panel of PI3K/AKT/mTOR inhibitors resulted in marked reduction of cell viability. CONCLUSIONS: A large microRNA cluster on chr19q13.42 is a transcriptional hallmark of type A and AB thymomas. Furthermore, this cluster activates the PI3K pathway, suggesting the possible exploration of PI3K inhibitors in patients with these subtypes of tumour. This work has led to the initiation of a phase II clinical trial of PI3K inhibition in relapsed or refractory thymomas (http://clinicaltrials.gov/ct2/show/NCT02220855).
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    Whole-Genome Sequencing to Identify the Genetic Etiology of a Spontaneous Thymoma Mouse Model
    (JPGN Reports, 2021) Conces, Madison L.; Hancock, Bradley A.; Atale, Rutuja; Solzak, Jeffrey P.; Bunting, Karen; Corvelo, Andre; Field, Loren; Badve, Sunil; Liu, Jianyun; Brutkiewicz, Randy R.; Loehrer, Patrick J.; Radovich, Milan; Pediatrics, School of Medicine
    Background: A mouse model for thymoma was previously created serendipitously by the random introduction of a transgene consisting of a mouse α-cardiac promoter, a constitutively active human transforming growth factor-β, and a simian virus 40 integration sequence into C3HeB/FeJ mice. Previous data demonstrated that the likely cause of thymomas in the thymoma mouse model was due to insertional mutagenesis by the transgene. At the time, fluorescence in situ hybridization was used to localize the transgene to the short arm of chromosome 2 (Chr2qF2-G region). In this exploratory study, we aimed to identify the exact insertion site of the transgene as this could provide clues to the genetic causation of thymomas in humans. Materials and Methods: To identify the insertion site of the transgene, germline DNA from the thymoma mouse model was sequenced using low-pass, fragment-library, whole genome sequencing. Long-insert mate pair whole genome sequencing was employed to traverse the repetitive regions of the mouse’s genome and identify the integration site. Results: The transgene was found to be integrated into a repetitive area of the mouse genome, specifically on Chr2qF1 within the intron of the FAM227B gene. Tandem integration of the transgene was observed with enumeration of an estimated 30 copies. Initial results suggested that a nearby gene, fibroblast growth factor 7 (Fgf7), could be affected by the gene insertion. Conclusions: Whole genome sequencing of this thymoma mouse model identified the region of tandem integration of a transgene on Chr2qF1 that may have potential translational implications in helping to understand the genomic etiology of thymoma in humans.