Histone variant H3.3 promotes experimental metastasis in alveolar rhabdomyosarcoma [RNA-Seq]

In this study, we show that histone variant H3.3 is overexpressed in ARMS patient-derived cell lines and patient tumour specimens. Functionally, knockdown of H3F3A significantly impairs the ability of ARMS cells to undertake migration and invasion and reduces Rho activation in vitro. In addition, a striking reduction in metastatic tumour burden and improved survival is apparent in vivo. Through RNA-sequencing and ChIP-sequencing analyses, we identified Melanoma Cell Adhesion Molecule (MCAM/CD146) as a direct downstream target of H3.3. Therefore, this study identifies a novel H3.3- MCAM axis involved in ARMS metastatic phenotypes, and supports the development of MCAM as a therapeutic target for this disease. Overall design: RH41 cells were treated with control siRNA (siscr) or H3F3A-specific siRNA (siH3F3A) for 48 hours, after which total RNA was collected with TRIzol reagent. RNA was purified and quality of purified RNA was checked using Nanodrop and gel electrophoresis. Two samples of siscr and 3 samples of siH3F3A were used for sequencing analysis, done by Novogene.