mannich-bases and Lymphoma

In the current work, we report that specific inhibition of Janus tyrosine kinase (JAK3) via NC1153 induces apoptosis of certain leukemia/lymphoma cell lines. Affymetrix microarray profiling following NC1153 treatment unveiled JAK3 dependent survival modulating pathways (p53, TGF-beta, TNFR and ER stress) in Kit225 cells. IL-2 responsive NC1153 target genes were regulated in human JAK3 positive, but not in JAK3 negative lymphoid tumor cells. Moreover, primary lymphoma samples revealed that a number of these genes were reciprocally regulated during disease progression and JAK3 inhibition suggesting that downstream targets of JAK3 could be exploited in the development of novel cancer treatment regimes.

Topics: Apoptosis; Cell Line, Tumor; Cell Survival; Disease Progression; Dose-Response Relationship, Drug; Enzyme Activation; Gene Expression Regulation, Neoplastic; Humans; Interleukin-2; Janus Kinase 3; Lymphoma; Mannich Bases; Signal Transduction; STAT5 Transcription Factor

Signal Transducer and Activator of Transcription 5 A and B (STAT5) are key survival factors in cells of the lymphoid lineage. Identification of novel, tissue-specific STAT5 regulated genes would advance the ability to combat diseases due to aberrant STAT5 signaling. In the present work a library of human STAT5 bound genomic elements was created and validated.. Of several STAT5 responsive genomic regulatory elements identified, one was located within the first intron of the human BCL10 gene. Chromatin immuno-precipitation reactions confirmed constitutive in vivo STAT5 binding to this intronic fragment in various human lymphoid tumor cell lines. Interestingly, non-phosphorylated STAT5 was found in the nuclei of Kit225 and YT cells in the absence of cytokine stimulation that paralleled constitutive NFkappaB activation. Inhibition of the hyperactive JAK3/STAT5 pathway in MT-2 cells via the Mannich-base, NC1153, diminished the constitutive in vivo occupancy of BCL10-SBR by STAT5, reduced NFkappaB activity and BCL10 protein expression in a dose dependent manner. Moreover, depletion of STAT5 via selective antisense oligonucleotide treatment similarly resulted in decreased BCL10 mRNA and protein expression, cellular viability and impaired NFkappaB activity independent of IL-2.. These results suggest that the NFkappaB regulator BCL10 is an IL-2-independent STAT5 target gene. These findings proffer a model in which un-activated STAT5 can regulate pathways critical for lymphoid cell survival and inhibitors that disrupt STAT5 function independent of tyrosine phosphorylation may be therapeutically effective in treating certain leukemias/lymphomas.

Topics: Adaptor Proteins, Signal Transducing; B-Cell CLL-Lymphoma 10 Protein; Binding Sites; Blotting, Western; Cell Line; Cell Line, Tumor; Cell Survival; Chromatin Immunoprecipitation; Dose-Response Relationship, Drug; Electrophoretic Mobility Shift Assay; Gene Expression Regulation, Neoplastic; Genomic Library; Humans; Interleukin-2; Janus Kinase 3; Lymphoma; Mannich Bases; NF-kappa B; Oligodeoxyribonucleotides, Antisense; Phosphorylation; Protein Binding; Response Elements; Reverse Transcriptase Polymerase Chain Reaction; Signal Transduction; STAT5 Transcription Factor