Glutathione-S-transferase theta 2 (GSTT2) modulates the tumor microenvironment and the response to BCG immunotherapy in a murine orthotopic model of bladder cancer

Whilst M. bovis Bacillus Calmette-Guérin (BCG) therapy remains the gold-standard for treatment of high-risk non-muscle invasive bladder cancer (BC), 30-40% of patients fail therapy, resulting in disease recurrence and progression. Loss of glutathione-S-transferase theta 2 (GSTT2) expression has been associated with improved response to fewer instillations of BCG. To understand these responses, wild-type (WT) and GSTT2-knockout (KO) mice were implanted orthotopically with MB49-PSA BC cells, and mice were treated with four weekly BCG instillations, after which the bladders were harvested for single-cell RNA sequencing. Single cells, isolated from the bladder of BCG-treated WT and KO mice, were barcoded using the whole-transcriptome kit from Parse Biosciences and sequenced (HiSeq PE150). The reads were aligned to the mouse genome (GRCm39) with the split-pipe (v0.9.6p) program (from Parse).