ABSTRACT
PURPOSE: We investigated how dual inhibition of the molecular mechanism of mammalian target of rapamycin (mTOR) downstream of S6K1 and the eukaryotic initiation factor 4E (eIF4E) can lead to suppression of proliferation and progression of urothelial carcinoma. MATERIALS AND METHODS: We characterized the molecular mechanism of the mTOR pathway in the T24 and 5637 urothelial carcinoma cell lines by interfering with different molecular components using rapamycin and short interfering (siRNA) technology (S6K1 or elF4E) and analyzed the effects on molecular activation status, cell growth, proliferation, and invasion. RESULTS: A high concentration of rapamycin (10 µM) blocked both S6K1 and elF4E phosphorylation and inhibited cell proliferation in T24 and 5637 cells. The inhibition of both S6K1 and elF4E phosphorylation by rapamycin reduced cell viability and proliferation more than transfection of siRNA against S6K1 or elF4E in 5637 and T24 cells. Cells silenced for S6K1 or elF4E expression exhibited significantly reduced cell migration and invasion compared with those of the control but inhibition of both S6K1 and elF4E phosphorylation by rapamycin reduced cell migration and invasion more than siRNA transfection against S6K1 or elF4E in 5637 and T24 cells. CONCLUSION: These findings suggest that both the mTOR pathway downstream of eukaryotic initiation factor 4E and S6K1 can be successfully inhibited, therefore, the recurrence of bladder cancer can be prevented by high-dose rapamycin only, suggesting that 4E-BP1 might be still under mTORC1.
Subject(s)
Cell Proliferation , Eukaryotic Initiation Factor-4E/genetics , RNA Interference , Ribosomal Protein S6 Kinases, 70-kDa/genetics , Antibiotics, Antineoplastic/pharmacology , Blotting, Western , Cell Line, Tumor , Cell Movement/drug effects , Cell Movement/genetics , Cell Survival/drug effects , Cell Survival/genetics , Dose-Response Relationship, Drug , Eukaryotic Initiation Factor-4E/metabolism , Humans , Neoplasm Invasiveness , Phosphorylation/drug effects , Ribosomal Protein S6 Kinases, 70-kDa/metabolism , Signal Transduction/drug effects , Sirolimus/pharmacology , TOR Serine-Threonine Kinases/metabolism , Urinary Bladder Neoplasms/genetics , Urinary Bladder Neoplasms/metabolism , Urinary Bladder Neoplasms/pathologyABSTRACT
AIM: To evaluate the expression of leptin and leptin receptor in benign prostatic hyperplasia (BPH) and prostate cancer (PCa), and to investigate whether they are associated with the development and progression of PCa. METHODS: Immunohistochemical staining was performed to examine the expression of leptin and leptin receptor in BPH and PCa. PCa was divided into three groups: localized PCa, locally advanced PCa and metastatic PCa. The positive staining was identified and the percentage of the positive staining was graded. We also assessed the relationship between both the Gleason score and body mass index (BMI) and PCa. RESULTS: The percentage of the leptin expression in PCa was significantly higher than that in BPH (P < 0.01). For the PCa group, the expressed levels of leptin showed a considerable correlation with localized PCa and metastatic PCa (P < 0.05). Leptin receptor, however, did not reveal a definite difference between BPH and PCa. The expression of leptin indicated a significant difference between well-differentiated PCa (Gleason score =or< 6) and poorly differentiated PCa (Gleason score 8?0) (P < 0.05). The relation between the leptin expression level in PCa and the BMI was not remarkable (P = 0.447). CONCLUSION: Our results suggest that leptin might have a promoting effect on the carcinogenesis and progression of PCa.
Subject(s)
Leptin/biosynthesis , Prostate/metabolism , Prostatic Hyperplasia/metabolism , Prostatic Neoplasms/metabolism , Receptors, Leptin/biosynthesis , Aged , Biomarkers , Body Mass Index , Disease Progression , Humans , Immunohistochemistry , Male , Middle Aged , Neoplasm Metastasis , Prostatic Hyperplasia/pathology , Prostatic Neoplasms/pathologyABSTRACT
We demonstrate that surface plasmon resonance (SPR) is applicable to the optical detection of neural signals. A low-noise SPR sensor was developed as a label- and artifact-free method for the extracellular recording of neural activity. The optical responses obtained from a rat sciatic nerve were highly correlated with simultaneously recorded electrical responses. Additional studies with stimulation intensity and lidocaine further confirmed that the optically measured signals originated from neural activities.
