ABSTRACT
The B-cell chronic lymphocytic leukemia (CLL)/lymphoma 11B gene (BCL11B) encodes a Krüppel-like zinc-finger protein, which plays a crucial role in thymopoiesis and has been associated with hematopoietic malignancies. It was hypothesized that BCL11B may act as a tumor-suppressor gene, but its precise function has not yet been elucidated. Here, we demonstrate that the survival of human T-cell leukemia and lymphoma cell lines is critically dependent on Bcl11b. Suppression of Bcl11b by RNA interference selectively induced apoptosis in transformed T cells whereas normal mature T cells remained unaffected. The apoptosis was effected by simultaneous activation of death receptor-mediated and intrinsic apoptotic pathways, most likely as a result of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) upregulation and suppression of the Bcl-xL antiapoptotic protein. Our data indicate an antiapoptotic function of Bcl11b. The resistance of normal mature T lymphocytes to Bcl11b suppression-induced apoptosis and restricted expression pattern make it an attractive therapeutic target in T-cell malignancies.
Subject(s)
Apoptosis/physiology , DNA-Binding Proteins/antagonists & inhibitors , Leukemia, T-Cell/metabolism , Lymphoma/metabolism , Repressor Proteins/antagonists & inhibitors , T-Lymphocytes/metabolism , Tumor Suppressor Proteins/antagonists & inhibitors , Blotting, Western , Cell Line, Tumor , Flow Cytometry , Humans , Jurkat Cells , Leukemia, T-Cell/genetics , Lymphoma/genetics , RNA Interference , RNA, Messenger/analysis , RNA, Small Interfering , Reverse Transcriptase Polymerase Chain Reaction , T-Lymphocytes/pathology , TNF-Related Apoptosis-Inducing Ligand/metabolism , Transcription, Genetic , bcl-X Protein/metabolismABSTRACT
METHOD: In a multicenter, placebo-controlled double-blind study, the efficacy of the Crataegus-Specialextrakt WS 1442 in patients with NYHA stage II cardiac insufficiency was investigated. A total of 136 patients with this diagnosis were admitted to the study and, following a 2-week run-in phase, treated with Crataegus-Specialextract or placebo over a period of 8 weeks. The primary target parameter was the change in the difference of the pressure, heart rate product (systolic blood pressure x heart rate/100) (PHRP 50 W load vs. rest) measured at the beginning and end of treatment. RESULTS: On the basis of this variable, a clear improvement in the performance of the heart was shown in the group receiving the test substance, while the condition of the placebo group progressively worsened. The therapeutic difference between the groups was statistically significant. The positive result for the objective efficacy parameter was confirmed by a statistically obvious superiority of Crataegus in the patient's own assessment of improvement in the main symptoms (reduced performance, shortness of breath, ankle edema etc.). In addition, active treatment led, in comparison with placebo, to a considerably better quality of life for the patient, in particular with respect to mental well-being. The tolerability of the active substance proved to be very good-as shown by comprehensive laboratory investigations and the recording of undesirable events. CONCLUSION: All in all, the results of the present clinical investigation confirm those of previous studies showing that Crataegus-Specialextrakt WS 1442 is an effective and low-risk phytotherapeutic form of treatment in patients with NYHA II cardiac insufficiency.
