nitrophenols and Autoimmune-Lymphoproliferative-Syndrome

Autoimmune lymphoproliferative syndrome (ALPS) is typically caused by mutations in genes of the extrinsic FAS mediated apoptotic pathway, but for about 30% of ALPS-like patients the genetic diagnosis is lacking. We analyzed 30 children with ALPS-like disease of unknown cause and identified two dominant gain-of-function mutations of the Signal Transducer And Activator Of Transcription 3 (STAT3, p.R278H, p.M394T) leading to increased transcriptional activity. Hyperactivity of STAT3, a known repressor of FAS, was associated with decreased FAS-mediated apoptosis, mimicking ALPS caused by FAS mutations. Expression of BCL2 family proteins, further targets of STAT3 and regulators of the intrinsic apoptotic pathway, was disturbed. Cells with hyperactive STAT3 were consequently more resistant to intrinsic apoptotic stimuli and STAT3 inhibition alleviated this effect. Importantly, STAT3-mutant cells were more sensitive to death induced by the BCL2-inhibitor ABT-737 indicating a dependence on anti-apoptotic BCL2 proteins and potential novel therapeutic options.

Topics: Apoptosis; Autoimmune Lymphoproliferative Syndrome; Biphenyl Compounds; Butylated Hydroxytoluene; Case-Control Studies; Child, Preschool; Enzyme-Linked Immunosorbent Assay; Family; Fas Ligand Protein; fas Receptor; Female; Gene Expression Profiling; Germ-Line Mutation; Humans; Immunoblotting; Immunophenotyping; Leukocytes, Mononuclear; Lymphocytes; Nitrophenols; Piperazines; Proto-Oncogene Proteins c-bcl-2; Real-Time Polymerase Chain Reaction; Reverse Transcriptase Polymerase Chain Reaction; Sequence Analysis, DNA; STAT3 Transcription Factor; Sulfonamides; T-Lymphocytes

Autoimmune lymphoproliferative syndrome (ALPS) is a human disorder of T cell homeostasis caused by mutations that impair FAS-mediated apoptosis. A defining characteristic of ALPS is the expansion of double negative T cells (DNTC). Relatively little is known about how defective FAS-driven cell death and the Bcl-2 apoptotic pathway intersect in ALPS patients.. We studied changes in Bcl-2 family member expression in ALPS to determine whether the Bcl-2 pathway might provide a therapeutic target.. We used flow cytometry to analyze the expression of pro- and anti-apoptotic Bcl-2 family members in T cells from 12 ALPS patients and determined the in vitro sensitivity of ALPS DNTC to the pro-apoptotic BH3 mimetic, ABT-737.. The pro-apoptotic molecule, Bim, was significantly elevated in DNTC. Although no general pattern of individual anti-apoptotic Bcl-2 family members emerged, increased expression of Bim was always accompanied by increased expression of at least 1 anti-apoptotic Bcl-2 family member. Strikingly, Bim levels in DNTC correlated significantly with serum IL-10 in ALPS patients, and IL-10 was sufficient to mildly induce Bim in normal and ALPS T cells via a Janus kinase/signal transducer and activator of transcription 3-dependent mechanism. Finally, ABT-737 preferentially killed ALPS DNTC in vitro.. Combined, these data show that an IL-10/Janus kinase/signal transducer and activator of transcription 3 pathway drives Bim expression in ALPS DNTC, which renders them sensitive to BH3 mimetics, uncovering a potentially novel therapeutic approach to ALPS.

Topics: Adolescent; Antineoplastic Agents; Apoptosis Regulatory Proteins; Autoimmune Lymphoproliferative Syndrome; Bcl-2-Like Protein 11; bcl-X Protein; Biphenyl Compounds; Case-Control Studies; Child; Child, Preschool; fas Receptor; Female; Gene Expression Regulation; Humans; Infant; Interleukin-10; Janus Kinase 1; Male; Membrane Proteins; Mutation; Myeloid Cell Leukemia Sequence 1 Protein; Nitrophenols; Piperazines; Primary Cell Culture; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-bcl-2; Signal Transduction; STAT3 Transcription Factor; Sulfonamides; T-Lymphocytes