Suburothelial myofibroblasts (sMF) are located underneath the urothelium in close proximity to afferent nerves and show spontaneous calcium activity in vivo and in vitro. They express purinergic receptors and calcium transients can be evoked by ATP. Therefore they are supposed to be involved in afferent signaling of the bladder fullness. Myofibroblast cultures, established from cystectomies, were challenged by exogenous ATP in presence or absence of purinergic antagonist. Fura-2 calcium imaging was used to monitor ATP (10-16 to 10-4 mol/l) induced alterations of calcium activity. Purinergic receptors (P2X1, P2X2, P2X3) were analysed by confocal immunofluorescence. We found spontaneous calcium activity in 55.18% ± 1.65 (mean ± SEM) of the sMF (N=48 experiments). ATP significantly increased calcium activity even at 10-16 mol/l. The calcium transients were partially attenuated by subtype selective antagonist (TNP-ATP, 1μM; A-317491, 1μM), and were mimicked by the P2X1, P2X3 selective agonist α,β-methylene ATP. The expression of purinergic receptor subtypes in sMF was confirmed by immunofluorescence. Our experiments demonstrate for the first time that ATP can modulate spontaneous activity and induce intracellular Ca2+ response in cultured sMF at very low concentrations, most likely involving ionotropic P2X receptors. These findings support the notion that sMF are able to register bladder fullness very sensitively, which predestines them for the modulation of the afferent bladder signaling in normal and pathological conditions.:1. Introduction............................................................................ 1 1.1. Anatomy and histology of the human urinary bladder..................... 1 1.1.1. Anatomy of the human urinary bladder..................................... 1 1.1.2. Structure of the human urinary bladder wall............................... 2 1.2. Normal bladder function and bladder dysfunction.......................... 3 1.2.1 Normal bladder function......................................................... 3 1.2.2 Sensory aspect.................................................................... 4 1.2.3 Overactivity or hypersensitivity of bladder.................................. 5 1.3 The role of functional cell types and interaction in urinary bladder... 6 1.3.1 The role of urothelium.......................................................... 7 1.3.2Theroleofsuburotheliamyofibroblast...................................... 7 1.3.3Theroleofdetrusorsmoothmusclecells.................................. 9 1.3.4 Possible interactions in urinary bladder cell types........................ 10 1.4 ATP function and Purinergic signalling in bladder........................... 11 1.5 Spontaneous activity of bladder................................................... 13 2. Objective.................................................................................. 15 3. Material and methods............................................................... 16 3.1. Ethics Statement........................................................................ 16 3.2. Cell preparation.......................................................................... 16 3.3. Solutions and chemicals............................................................. 19 3.4. Intracellular calcium measurements............................................. 20 2.4.1. Preparing cells for Calcium Imaging.......................................... 20 2.4.2. Preparing workspace of calcium imaging................................... 20 2.4.3. Calcium imaging recording...................................................... 22 3.5 Data analysis with automated Fluorescence analysis..................... 22 3.6 Confocal Immunofluorescence.................................................... 25 3.7 Statistics................................................................................. 26 4. Results.................................................................................. 27 4.1 Spontaneous calcium activity of sMF........................................... 27 4.2 ATP effects on calcium response in sMF...................................... 27 4.3 Analysis of purinergic receptors involved.................................... 30 3.3.1 Agonist stimulation.............................................................. 30 3.3.2 Signal inhibition by specific antagonists................................... 31 4.4 Confocal immunofluorescence of purinergic receptors.................. 32 5. Discussion............................................................................. 34 5.1 Myofibroblast identification....................................................... 34 5.2 Spontaneous activity in the bladder............................................ 36 5.3 ATP modulated calcium activity in sMF....................................... 37 5.4 purinergic signalling in sMF........................................................ 39 6. Summary................................................................................ 42 7. References.............................................................................. 45 Declaration............................................................................. 50 Acknowledgements................................................................. 51

No / Radiotherapy is a major treatment modality used to treat muscle-invasive bladder cancer, with patient outcomes similar to surgery. However, radioresistance is a significant factor in treatment failure. Cell-free extracts of muscle-invasive bladder tumors are defective in nonhomologous end-joining (NHEJ), and this phenotype may be used clinically by combining radiotherapy with a radiosensitizing drug that targets homologous recombination, thereby sparing normal tissues with intact NHEJ. The response of the homologous recombination protein RAD51 to radiation is inhibited by the small-molecule tyrosine kinase inhibitor imatinib. Stable RT112 bladder cancer Ku knockdown (Ku80KD) cells were generated using short hairpin RNA technology to mimic the invasive tumor phenotype and also RAD51 knockdown (RAD51KD) cells to show imatinib's pathway selectivity. Ku80KD, RAD51KD, nonsilencing vector control, and parental RT112 cells were treated with radiation in combination with either imatinib or lapatinib, which inhibits NHEJ and cell survival assessed by clonogenic assay. Drug doses were chosen at approximately IC40 and IC10 (nontoxic) levels. Imatinib radiosensitized Ku80KD cells to a greater extent than RAD51KD or RT112 cells. In contrast, lapatinib radiosensitized RAD51KD and RT112 cells but not Ku80KD cells. Taken together, our findings suggest a new application for imatinib in concurrent use with radiotherapy to treat muscle-invasive bladder cancer. Cancer Res; 73(5); 1611-20. (c)2012 AACR.

No / We identify cytochrome P450 1A1 (CYP1A1) as a target for tumor-selective drug development in bladder cancer and describe the characterization of ICT2700, designed to be metabolized from a prodrug to a potent cytotoxin selectively by CYP1A1. Elevated CYP1A1 expression was shown in human bladder cancer relative to normal human tissues. RT112 bladder cancer cells, endogenously expressing CYP1A1, were selectively chemosensitive to ICT2700, whereas EJ138 bladder cells that do not express CYP1A1 were significantly less responsive. Introduction of CYP1A1 into EJ138 cells resulted in 75-fold increased chemosensitivity to ICT2700 relative to wild-type EJ138. Negligible chemosensitivity was observed in ICT2700 in EJ138 cells expressing CYP1A2 or with exposure of EJ138 cells to CYP1B1- or CYP3A4-generated metabolites of ICT2700. Chemosensitivity to ICT2700 was also negated in EJ138-CYP1A1 cells by the CYP1 inhibitor alpha-naphthoflavone. Furthermore, ICT2700 did not induce expression of the AhR-regulated CYP1 family, indicating that constitutive CYP1A1 expression is sufficient for activation of ICT2700. Consistent with the selective activity by CYP1A1 was a time and concentration-dependent increase in gamma-H2AX protein expression, indicative of DNA damage, associated with the activation of ICT2700 in RT112 but not EJ138 cells. In mice-bearing CYP1A1-positive and negative isogenic tumors, ICT2700 administration resulted in an antitumor response only in the CYP1A1-expressing tumor model. This antitumor response was associated with detection of the CYP1A1-activated metabolite in tumors but not in the liver. Our findings support the further development of ICT2700 as a tumor-selective treatment for human bladder cancers.

No / Fibroblast growth factor receptors (FGFR) play key roles in proliferation, differentiation, and tumorigenesis. Many urothelial carcinomas contain activating point mutations or increased expression of FGFR3. However, little is known about the role of other FGFRs. We examined FGFR expression in telomerase-immortalized normal human urothelial cells, urothelial carcinoma cell lines, and tumor samples and showed that FGFR1 expression is increased in a high proportion of cell lines and tumors independent of stage and grade. To determine the role of FGFR1 in low-stage bladder cancer, we overexpressed FGFR1 in telomerase-immortalized normal human urothelial cells and examined changes in proliferation and cell survival in response to FGF2. FGFR1 stimulation increased proliferation and reduced apoptosis. To elucidate the mechanistic basis for these alterations, we examined the signaling cascades activated by FGFR1. FRS2alpha and PLCgamma were activated in response to FGF2, leading to activation of the mitogen-activated protein kinase pathway. The level of mitogen-activated protein kinase activation correlated with the level of cyclin D1, MCL1, and phospho-BAD, which also correlated with FGFR-induced proliferation and survival. Knockdown of FGFR1 in urothelial carcinoma cell lines revealed differential FGFR1 dependence. JMSU1 cells were dependent on FGFR1 expression for survival but three other cell lines were not. Two cell lines (JMSU1 and UMUC3) were dependent on FGFR1 for growth in soft agar. Only one of the cell lines tested (UMUC3) was frankly tumorigenic; here, FGFR1 knockdown inhibited tumor growth. Our results indicate that FGFR1 has significant effects on urothelial cell phenotype and may represent a useful therapeutic target in some cases of urothelial carcinoma.