OBJECTIVES: Truncating mutations in USP9X have been identified in oral squamous cell carcinoma patients. The aim of this study was to determine USP9X's functional role, if any, in head and neck cancer cells. MATERIALS AND METHODS: USP9X was depleted/overexpressed in head and neck cancer cell line: SCC15 (tongue), CAL27 (tongue), FaDu (pharynx) and Detroit 562 (pharynx). Cell proliferation was monitored using the CyQUANT assay, and cell cycle distribution was determined by flow cytometry. Immunoblot assays were conducted to assess protein levels. RT-qPCR was performed to determine Notch and Wnt pathway target gene expression. RESULTS: Our data showed a direct correlation between USP9X protein levels and proliferation, as well as Notch pathway activity in head and neck cancer cells. However, at least in FaDu, USP9X did not appear to regulate proliferation through the Notch pathway. Immunoblotting revealed a dramatic reduction in downstream targets of mTOR complex 1, namely total ribosomal protein (S6) and its phosphorylated form (pS6), when USP9X was depleted in FaDu cells. In contrast, in immortalized but non-tumorigenic HaCaT keratinocytes, USP9X depletion led to increase in cell proliferation, maintaining direct regulation of Notch activity. CONCLUSIONS: The functional role of USP9X was found to be context dependent. USP9X possibly promotes head and neck cancer cell proliferation through the mTOR pathway.
OBJECTIVES: Truncating mutations in USP9X have been identified in oral squamous cell carcinomapatients. The aim of this study was to determine USP9X's functional role, if any, in head and neck cancer cells. MATERIALS AND METHODS:USP9X was depleted/overexpressed in head and neck cancer cell line: SCC15 (tongue), CAL27 (tongue), FaDu (pharynx) and Detroit 562 (pharynx). Cell proliferation was monitored using the CyQUANT assay, and cell cycle distribution was determined by flow cytometry. Immunoblot assays were conducted to assess protein levels. RT-qPCR was performed to determine Notch and Wnt pathway target gene expression. RESULTS: Our data showed a direct correlation between USP9X protein levels and proliferation, as well as Notch pathway activity in head and neck cancer cells. However, at least in FaDu, USP9X did not appear to regulate proliferation through the Notch pathway. Immunoblotting revealed a dramatic reduction in downstream targets of mTOR complex 1, namely total ribosomal protein (S6) and its phosphorylated form (pS6), when USP9X was depleted in FaDu cells. In contrast, in immortalized but non-tumorigenic HaCaT keratinocytes, USP9X depletion led to increase in cell proliferation, maintaining direct regulation of Notch activity. CONCLUSIONS: The functional role of USP9X was found to be context dependent. USP9X possibly promotes head and neck cancer cell proliferation through the mTOR pathway.
Authors: Jesse L Cox; Phillip J Wilder; Erin L Wuebben; Michel M Ouellette; Michael A Hollingsworth; Angie Rizzino Journal: Cancer Biol Ther Date: 2014-05-19 Impact factor: 4.742
Authors: Alfredo A Molinolo; Stephen M Hewitt; Panomwat Amornphimoltham; Somboon Keelawat; Samraeung Rangdaeng; Abelardo Meneses García; Ana R Raimondi; Rafael Jufe; María Itoiz; Yan Gao; Dhananjaya Saranath; George S Kaleebi; George H Yoo; Lee Leak; Ernest M Myers; Satoru Shintani; David Wong; H Davis Massey; W Andrew Yeudall; Fulvio Lonardo; John Ensley; J Silvio Gutkind Journal: Clin Cancer Res Date: 2007-09-01 Impact factor: 12.531
Authors: Pedro A Pérez-Mancera; Alistair G Rust; Louise van der Weyden; Glen Kristiansen; Allen Li; Aaron L Sarver; Kevin A T Silverstein; Robert Grützmann; Daniela Aust; Petra Rümmele; Thomas Knösel; Colin Herd; Derek L Stemple; Ross Kettleborough; Jacqueline A Brosnan; Ang Li; Richard Morgan; Spencer Knight; Jun Yu; Shane Stegeman; Lara S Collier; Jelle J ten Hoeve; Jeroen de Ridder; Alison P Klein; Michael Goggins; Ralph H Hruban; David K Chang; Andrew V Biankin; Sean M Grimmond; Lodewyk F A Wessels; Stephen A Wood; Christine A Iacobuzio-Donahue; Christian Pilarsky; David A Largaespada; David J Adams; David A Tuveson Journal: Nature Date: 2012-04-29 Impact factor: 49.962