title: SRSF3 and hnRNP H1 regulate a splicing hotspot of HER2 in breast cancer cells.
abstract: Overexpression of the oncogene HER2 occurs in 20-30% of invasive breast cancer and is associated with poor prognosis. A number of different splice variants of HER2 have been identified which produce functionally different proteins. Previously these splice variants have been investigated separately, but in the present study we collectively look at the expression and regulation of a group of HER2 splice variants produced by a splicing hotspot. Initial investigation in a cohort of tumor samples showed large variations in HER2 variant expression between patient samples. RNA interference studies identified 2 splicing factors involved in the regulation of splicing within this region, hnRNP H1 and SRSF3. siRNA targeting hnRNP H1 increases levels of X5 and the oncogenic variant Δ16HER2. Furthermore RNA chromatography assays demonstrated binding of hnRNP H1 to RNA in this region. Additionally the proto-oncogene SRSF3 was also identified as an important regulator of splicing with SRSF3 knockdown resulting in changes in all the splice variants located at the hotspot. Most notably knockdown of SRSF3 resulted in a switch from the oncogenic Δ16HER2 to p100 which inhibits cell proliferation. Binding of SRSF3 to RNA within this region was also demonstrated by RNA chromatography and more specifically 2 SRSF3 binding sites were identified within exon 15. SRSF3 and hnRNP H1 are the first splicing factors identified which regulate the production of these functionally distinct HER2 splice variants and therefore maybe important for the regulation of HER2 signaling.
authors.affiliation: a Institute of Cellular Medicine; Faculty of Medical Sciences; Newcastle University ; Newcastle upon Tyne , UK.
authors.forename: Hannah
authors.initials: H
authors.lastname: Gautrey
authors.affiliation: a Institute of Cellular Medicine; Faculty of Medical Sciences; Newcastle University ; Newcastle upon Tyne , UK.
authors.forename: Claire
authors.initials: C
authors.lastname: Jackson
authors.affiliation: a Institute of Cellular Medicine; Faculty of Medical Sciences; Newcastle University ; Newcastle upon Tyne , UK.
authors.forename: Anna-Lena
authors.initials: AL
authors.lastname: Dittrich
authors.affiliation: b Queen Elizabeth Hospital, Gateshead ; Tyne and Wear , UK.
authors.forename: David
authors.initials: D
authors.lastname: Browell
authors.affiliation: c Northern Institute for Cancer Research; Faculty of Medical Sciences; Newcastle University ; Newcastle upon Tyne , UK.
authors.forename: Thomas
authors.initials: T
authors.lastname: Lennard
authors.affiliation: a Institute of Cellular Medicine; Faculty of Medical Sciences; Newcastle University ; Newcastle upon Tyne , UK.
authors.forename: Alison
authors.initials: A
authors.lastname: Tyson-Capper
mesh_terms: D017398:Alternative Splicing / Q000235:genetics*; D001665:Binding Sites; D001943:Breast Neoplasms / Q000235:genetics* / Q000473:pathology; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000235:genetics; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D055785:Gene Knockdown Techniques; D034541:Heterogeneous-Nuclear Ribonucleoprotein Group F-H / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D000090063:Proto-Oncogene Mas; D016601:RNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000235:genetics* / Q000378:metabolism; D000068103:Serine-Arginine Splicing Factors
chemical_list: D034541:Heterogeneous-Nuclear Ribonucleoprotein Group F-H; D000090063:Proto-Oncogene Mas; D016601:RNA-Binding Proteins; D018719:Erb-b2 Receptor Tyrosine Kinases; D000068103:Serine-Arginine Splicing Factors; C000715470:MAS1 protein, human; C491388:SRSF3 protein, human; C508053:ERBB2 protein, human
keywords: HER2; RNA binding proteins; SRSF3; breast cancer; hnRNP H1; splice variants