TY - JOUR AB - Bladder cancer and head and neck squamous cell carcinoma (HNSCC) are frequent but lack efficient therapies especially in advanced disease. Almost no studies on mTOR function and inhibition in these tumor entities have been reported. We examined the gene and protein expression levels of mTOR and its activated form (pmTOR) in three human bladder carcinoma cell lines (RT-4, T24, EJ28) and three HNSCC cell lines (PCI-1, PCI-13, BHY). Furthermore, the consequences of mTOR inhibition by mTOR-specific siRNAs and the mTOR inhibitor temsirolimus were analysed in vitro using immunohistochemical Ki-67 staining, mTOR and pmTOR western blot analysis, MTT assay, as well as cell cycle analysis with flow cytometry. Especially pmTOR protein expression levels showed marked differences between cell lines. siRNA transfection was associated with dose-dependent target protein reduction but not proliferation inhibition or apoptosis. On the contrary, temsirolimus significantly reduced cell viability and induced apoptosis and cell cycle arrest. According to these data, bladder cancer and HNSCC are promising tumor entities for mTOR inhibition with temsirolimus. AD - Department of Urology, University at Lübeck, University Hospital Schleswig-Holstein, Campus Lübeck, Ratzeburger Allee 160, 23538 Lübeck, Germany Department of Otorhinolaryngology, University at Lübeck, University Hospital Schleswig-Holstein, Campus Lübeck, Ratzeburger Allee 160, 23538 Lübeck, Germany null AU - Schedel,Fiona AU - Pries,Ralph AU - Thode,Beate AU - Wollmann,Brigitte AU - Wulff,Sandra AU - Jocham,Dieter AU - Wollenberg,Barbara AU - Kausch,Ingo DA - 2011/03/01 DO - 10.3892/or.2011.1146 EP - 768 IS - 3 JO - Oncol Rep KW - mTOR temsirolimus bladder cancer head and neck squamous cell carcinoma PY - 2011 SN - 1021-335X 1791-2431 SP - 763 ST - mTOR inhibitors show promising in vitro activity in bladder cancer and head and neck squamous cell carcinoma T2 - Oncology Reports TI - mTOR inhibitors show promising in vitro activity in bladder cancer and head and neck squamous cell carcinoma UR - https://doi.org/10.3892/or.2011.1146 VL - 25 ER -