22RV1 prostate cancer cell line transfected with SPINK1 siRNA vs control siRNA

ETS gene fusions have been characterized in a majority of prostate cancers, however key molecular alterations in ETS negative cancers are unclear. Here we used an outlier meta-analysis (meta-COPA) to identify SPINK1 outlier-expression exclusively in a subset of ETS rearrangement negative cancers (~10% of total cases). We validated the mutual exclusivity of SPINK1 expression and ETS fusion status, demonstrated that SPINK1 outlier-expression can be detected non-invasively in urine and observed that SPINK1 outlier-expression is an independent predictor of biochemical recurrence after resection. We identified the aggressive 22RV1 cell line as a SPINK1 outlier-expression model, and demonstrate that SPINK1 knockdown in 22RV1 attenuates invasion, suggesting a functional role in ETS rearrangement negative prostate cancers. Keywords: Genetic Modification 22RV1 cells were infected with non-targeting siRNA or siRNA against SPINK1. For reported hybridizations, the reference channel is 22RV1 cells infected with non-targeting siRNA. Duplicate hybridizations were performed with duplicate dye flips, for a total of four arrays. Over and under-expressed signatures were generated by filtering to include only features with significant differential expression (PValueLogRatio < 0.01) in all hybridizations and Cy5/Cy3 ratios > or < 1 in all hybridizations.