Poster abstracts
Poster number 47 submitted by Akila Venkataramany
Understanding ERBB4 and IR alternative splicing in Ewing sarcoma formation and metastasis
Akila S. Venkataramany (Medical Scientist Training Program and Biomedical Sciences Training Program, OSUCOM; The Research Institute at Nationwide Childrens Hospital), Safiya Khurshid, PhD (Center for Childhood Cancer and Blood Diseases, The Research Institute at Nationwide Childrens Hospital), Matias Montes, PhD (Center for Childhood Cancer and Blood Diseases, The Research Institute at Nationwide Childrens Hospital), Pin-Yi Wang, PhD (Center for Childhood Cancer and Blood Diseases, The Research Institute at Nationwide Childrens Hospital), Timothy P. Cripe, MD PhD (Center for Childhood Cancer and Blood Diseases, The Research Institute at Nationwide Childrens Hospital; Department of Pediatrics, OSUCOM), Dawn S. Chandler, PhD (Center for Childhood Cancer and Blood Diseases, The Research Institute at Nationwide Childrens Hospital; Center for RNA Biology, OSU; Department of Pediatrics, OSUCOM)
Abstract:
Ewing sarcoma (ES) is the second most common pediatric bone malignancy, and most cases are molecularly defined by the EWS-FLI1 translocation, which results in a transcription factor that increases ES cell proliferation, angiogenesis, and metastasis. Previous research has suggested a role for the splicing network in ES pathogenesis. EWS-FLI1 has known interactions with the spliceosome to promote alternative splicing of oncogenic regulatory genes. Additionally, the IGF / insulin receptor (IR) and EGF receptor signaling pathways are upregulated in ES metastases. IR has two alternatively spliced isoforms, and IR-A is differentially expressed in cancers due to its high affinity binding to IGF-II. ERBB4, a protein in the EGFR pathway, has two juxtamembrane isoforms that are differentially expressed in ES cell lines and patient tumors. It is essential to characterize transcriptional changes from alternative splicing that promote ES formation and progression toward metastasis. We hypothesize that the pathogenesis and metastatic potential of ES is driven in part by alternative splicing and upregulation of specific isoforms of key genes (ERBB4, IR).
We will perform RNA biotinylated pulldown assays followed by western blot and in vitro splicing assays to explore the functions of the splicing factors that bind ERBB4/IR pre-mRNA. We will develop single strand oligonucleotides (SSOs) and adeno-associated virus vectors as novel therapeutics to examine their effect on ERBB4, IR, EWS-FLI1, and downstream targets in vitro and in vivo. To assess physiologic properties of ES cells after SSO treatment, we will perform cytotoxicity and metastasis assays. In mice implanted with ES PDX tumors, we will also check tumor burden and survival analyses after SSO treatment. By better understanding splicing in ES progression and metastasis, we may be able to identify targetable interactions at the transcriptional level and develop therapeutics that can improve the clinical outcomes of ES patients.
Keywords: Ewing sarcoma, alternative splicing, ERBB4, IR