👤 Mahmood Rasool

We previously used a myoblast model of fusion-positive rhabdomyosarcoma (FP-RMS) to show that FGF8, a PAX3-FOXO1 (P3F) transcriptional target, is required for P3F-driven tumorigenicity and, when aberrantly expressed, can maintain tumorigenicity in P3F-independent recurrent tumors. We report in this study that FGF8, FGFR1, and FGFR4 are often highly expressed in FP-RMS tumors. High FGF8 expression in FP-RMS cells is associated with high sensitivity to an FGFR4 inhibitor and a pan-FGFR inhibitor. Although downregulating FGF8 resulted in loss of sensitivity to these inhibitors, FGF8 upregulation in myoblasts decreased FGFR4 expression and sensitized the cells to an FGFR1 inhibitor and a pan-FGFR inhibitor. FGF8 downregulation of FGFR4 expression was reverted by inhibitors of FGFR1, MEK, or ERK, thus defining a signaling pathway by which FGF8 mediates this regulatory effect. Finally, high FGF8 expression in P3F-independent recurrent tumors was attributable to a rearrangement of viral long terminal repeat (LTR) sequences into the FGF8 3' untranslated region, resulting in increased FGF8 mRNA stability. These findings indicate that FGF8 exerts oncogenic effects in FP-RMS via FGFR4 and may exert oncogenic effects in P3F-independent relapses via FGFR1. Our study reveals the functional significance of FGF8 in FP-RMS and provides a rationale for preclinical studies of FGFR inhibitors in FP-RMS. Show less

Specific genetic anomalies or non-genetic factors could lead to epilepsy, but in various cases the underlying cause is unknown. Novel technologies, such as array comparative genomic hybridization, may reveal the copy number variants (CNVs), established as significant risk factor for epilepsy. This study carried out a high-density whole genome array- comparative genomic hybridization analysis with blood DNA samples from a cohort of twenty epilepsy patients to search for CNVs associated with epilepsy. Microdeletion of 14q31.1 was observed in four patients including two from the same family with loss of the NRXN3 gene; microdeletion of 15q12 in one patient with loss of the GABRG3 gene, and microduplication of 20q13.33 in three patients with loss of the gene group CHRNA4, KCNQ2, EEF1A2 and PPDPF were also found. These CNV findings were confirmed by real-time quantitative polymerase chain reaction. We have described, for the first time, numerous potential CNVs/genes implicated in epilepsy in the Saudi population. The study presents a better description of the genetic variations in epilepsy, and would eventually enable us to provide a foundation for understanding the critical genome regions which might be involved in the development of epilepsy. Show less