Investigation aimed for establishment of novel bladder cancer detection and treatment strategy system using centrosome amplification

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Objectives:The aims of this study are (1) to testify the role of centrosome amplification (CA) using bladder washing cytology specimen for the prediction of tumor recurrence and progression in non muscle-invasive bladder cancer, (2) to explore the specific genomic alterations (deletion, amplification) regarding CA, and (3) to identify the relation of CA to anticancer drug sensitivity to taxanes by comparing the status of CA with drug sensitivity using six established bladder cancer cell lines.Materials & Methods:(1) An immune-fluorescent staining for anti-pericentrin was applied to bladder washing cytology specimens as well as corresponding touch biopsy specimens obtained both from 85 human non muscle-invasive bladder cancers. CA was defined as cases with having more than 5% fraction of cells with three or more centrosome per cell. (2) An array-CGH (comparative genomic hybridization) using 4030 AC crone chip (MacArray) was applied to tumor genomic DNAs extracted from 70 human urothelia … More l cancers, and compared the copy number of entire chromosomes between DNA from cases with CA and those without CA. (3) Paclitaxel (final conc. : 0.1, 1, 10nM/ml) was continuously exposed to six human established bladder cancer cell lines (CA cell line : T24, EJ-1, 5637, J-82, TCC-sup, non-CA cell line : KK47, RT-4) in vitro, and compared CA status with drug sensitivity to paclitaxel.Results:(1) Out of 85 cases examined, CA and tumor progression was observed in 50 (59%) and 15 (18%) cases, respectively. A multivariate analysis by Cox-proportional hazard model revealed CA was a sole independent prognostic factor predicting for tumor progression (p=0.0098, Relative risk : 3.69, 95% CI : 1.28-13.44). CA detection using bladder washing specimens was successful in 20 out of 25 cased (80%), and correspondence rate between cytology and touch specimens was 95%. (2) High throughput genomic analysis demonstrated that cases with CA were significantly higher accumulated variant copy number, higher chromosome instability (CIN), and shorter period to tumor progression than those without CA. Specific chromosomal region with copy number aberrations included gains for 5p15.2,20p12.2, and losses for 2q37.3, 8p22, and 17p12, respectively. (3) All cell lines without CA demonstrated dose-response drug sensitivity to paclitaxel, while three of four cell lines with CA showed resistant to the drug.Conclusions:A serial experiments regarding CA demonstrated that (1) CA detection using bladder washing cytology specimens may become a non-invasive diagnostic tool for predicting tumor progression, (2) urothelial cancer including bladder may be biologically categorized by CA status, (3) CA status may predict clinical efficacy of anti-cancer chemotherapy using paclitaxel. Less