title: Thiopurines induce oxidative stress in T-lymphocytes: a proteomic approach.
abstract: Thiopurines are extensively used immunosuppressants for the treatment of inflammatory bowel disease (IBD). The polymorphism of thiopurine S-methyltransferase (TPMT) influences thiopurine metabolism and therapy outcome. We used a TPMT knockdown (kd) model of human Jurkat T-lymphocytes cells to study the effects of treatment with 6-mercaptopurine (6-MP) and 6-thioguanine (6-TG) on proteome and phosphoproteome. We identified thirteen proteins with altered expression and nine proteins with altered phosphorylation signals. Three proteins (THIO, TXD17, and GSTM3) with putative functions in cellular oxidative stress responses were altered by 6-TG treatment and another protein PRDX3 was differentially phosphorylated in TPMT kd cells. Furthermore, reactive oxygen species (ROS) assay results were consistent with a significant induction of oxidative stress by both TPMT knockdown and thiopurine treatments. Immunoblot analyses showed treatment altered expression of key antioxidant enzymes (i.e., SOD2 and catalase) in both wt and kd groups, while SOD1 was downregulated by 6-TG treatment and TPMT knockdown. Collectively, increased oxidative stress might be a mechanism involved in thiopurine induced cytotoxicity and adverse effects (i.e., hepatotoxicity) and an antioxidant cotherapy might help to combat this. Results highlight the significance of oxidative stress in thiopurines' actions and could have important implications for the treatment of IBD patients.
authors: Institute of Clinical Chemistry/UMG Laboratories, University Medical Centre Goettingen, 37075 Goettingen, Germany.
authors: Misbah
authors: M
authors: Misdaq
authors: Institute of Clinical Chemistry/UMG Laboratories, University Medical Centre Goettingen, 37075 Goettingen, Germany.
authors: Sonia
authors: S
authors: Ziegler
authors: Institute of Clinical Chemistry/UMG Laboratories, University Medical Centre Goettingen, 37075 Goettingen, Germany ; Medical Laboratories, 28357 Bremen, Germany.
authors: Nicolas
authors: N
authors: von Ahsen
authors: Institute of Clinical Chemistry/UMG Laboratories, University Medical Centre Goettingen, 37075 Goettingen, Germany.
authors: Michael
authors: 0000-0002-9255-2261
authors: M
authors: Oellerich
authors: Institute of Clinical Chemistry/UMG Laboratories, University Medical Centre Goettingen, 37075 Goettingen, Germany.
authors: Abdul R
authors: AR
authors: Asif
mesh_terms: D006801:Humans; D015212:Inflammatory Bowel Diseases / Q000188:drug therapy; D019169:Jurkat Cells; D015122:Mercaptopurine / Q000494:pharmacology*; D008780:Methyltransferases / Q000502:physiology; D018384:Oxidative Stress / Q000187:drug effects*; D010766:Phosphorylation; D040901:Proteomics / Q000379:methods*; D013601:T-Lymphocytes / Q000187:drug effects* / Q000378:metabolism; D013866:Thioguanine / Q000494:pharmacology*
chemical_list: D015122:Mercaptopurine; D008780:Methyltransferases; C022745:thiopurine methyltransferase; D013866:Thioguanine