u-0126 and Carcinoma--Renal-Cell

The expression and function of ribosomal s6 protein kinase 4 (RSK4) in renal cell carcinoma (RCC) are unknown.. Immunohistochemistry was used to detect the expression of RSK4 in RCC, and the relationship between RSK4 expression and clinicopathological features as well as prognosis of RCC patients was statistically analysed. Ectopic RSK4 expression in RCC cell lines was performed to determine its effect on cell cycle regulation, tumour invasiveness, and metastatic capability.. RSK4 was overexpressed in RCCs (P=0.003), compared with normal tissues, and the expression varied in different RCC subtypes (P=0.021), especially in two subtypes of papillary RCCs (P=0.001). RSK4 expression was positively correlated with high pT stage (P<0.001), high Fuhrman grade (P<0.001), lymph node involvement (P<0.001), and presence of distant metastasis (P=0.039), and could predict poor outcome in RCC patients. Molecular studies showed that overexpression of RSK4 could promote cell cycle progression and enhance the invasive and metastatic capability of RCC cell lines and vice versa.. The expression pattern and molecular mechanisms of RSK4 in RCCs indicate that it could be a potential independent prognostic factor and serve as a new potential therapeutic target for RCC patients.

Topics: Adolescent; Adult; Aged; Biomarkers, Tumor; Butadienes; Carcinoma, Renal Cell; Cell Cycle; Cell Line, Tumor; Child; Enzyme Inhibitors; Extracellular Signal-Regulated MAP Kinases; Female; Humans; Hyaluronan Receptors; Kidney Neoplasms; Male; Matrix Metalloproteinase 9; Middle Aged; Neoplasm Invasiveness; Neoplasm Metastasis; Nitriles; Prognosis; Pteridines; Ribosomal Protein S6 Kinases, 90-kDa; RNA Interference; RNA, Small Interfering; Young Adult

The objective of this study was to characterise the mechanism underlying acquired resistance to temsirolimus, an inhibitor of mammalian target of rapamycin (mTOR), in renal cell carcinoma (RCC).. A parental human RCC cell line, ACHN (ACHN/P), was continuously exposed to increasing doses of up to 20 μM of temsirolimus, and a cell line resistant to temsirolimus (ACHN/R), showing a sixfold higher IC50 than that of ACHN/P, was developed.. Following treatment with temsirolimus, phosphorylation of S6 kinase in ACHN/P was markedly inhibited, whereas there was no detectable expression of phosphorylated S6 in ACHN/R before and after temsirolimus treatment. However, AKT and p44/42 mitogen-activated protein kinase (MAPK) were constitutively phosphorylated even after temsirolimus treatment in ACHN/R, but not in ACHN/P. There was no significant difference between the sensitivities of ACHN/P and ACHN/R to KU0063794, a dual inhibitor of mTOR complex 1 (mTORC1) and mTORC2. Similar sensitivities to temsirolimus in ACHN/P and ACHN/R could be achieved by additional treatment with specific inhibitors of AKT- and MAPK-signaling pathways.. The activation of signal transduction pathways via mTORC2, but not via mTORC1, may have an important role in the acquisition of a resistant phenotype to temsirolimus in RCC.

Topics: Animals; Apoptosis; Butadienes; Carcinoma, Renal Cell; Cell Line, Tumor; Chromones; Drug Resistance, Neoplasm; Humans; Kidney Neoplasms; Male; Mechanistic Target of Rapamycin Complex 1; Mechanistic Target of Rapamycin Complex 2; Mice, Inbred BALB C; Mice, Nude; Mitogen-Activated Protein Kinases; Morpholines; Multiprotein Complexes; Nitriles; Phosphorylation; Protein Kinase Inhibitors; Proto-Oncogene Proteins c-akt; Pyrimidines; Ribosomal Protein S6 Kinases; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases