Arsenic trioxide induces apoptosis in B-cell chronic lymphocytic leukemic cells through down-regulation of survivin via the p53-dependent signaling pathway.

Arsenic trioxide (As2O3) can induce apoptosis in many tumors. However, the associated mechanisms are not clearly understood. We found that As2O3 significantly inhibited the proliferation of WSU-CLL cells and induced apoptosis in dose- and time-dependent manners. WSU-CLL cells treated with 2µM As2O3 showed survivin down-regulation and p53 up-regulation. Survivin siRNA combined with As2O3 further inhibited the proliferation of WSU-CLL cells. p53 inhibition by siRNA prevented the down-regulation of survivin by As2O3 and prevented the As2O3-induced cytotoxicity of WSU-CLL cells. These results suggest that As2O3 may be of therapeutic value for chronic lymphocytic leukemia.

[Study on the sequences of amino-acids and their gene codes of the related proteins of rifampin-dependent Mycobacterium tuberculosis].

OBJECTIVE: To study the sequences of amino-acids and their related genes of rifampin-dependent Mycobacterium tuberculosis. METHODS: The strains of rifampin-dependent, rifampin-resistant and rifampin-sensitive Mycobacterium tuberculosis were evaluated by L-J method. The proteins of 134 strains were analyzed by sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis (SDS-PAGE). The sequences of amino-acids of the proteins with differential expressions were determined by Q-TOF2 liquid chromatography-electra mist spray-quadrupole -time of flight cascade mass spectrograph (LC-ESI-MS-MS, Q-TOF2). The corresponding gene codes for the proteins were analyzed. RESULTS: The protein SDS-PAGE profile of 41 of 49 (41/49) rifampin-dependent strains showed a high expression of a protein band (molecular weight 43,000), representative of 30%-50% of the total proteins differed from rifampin resistance and the control strains. The protein profile of H(37)Rv standard strains, 28 (28/30) rifampin-sensitive strains and 44 (44/54) rifampin-resistant strains showed no relevant high expression. The protein of high expression was identified as the hypothetical protein Rv0341 of Mycobacterium tuberculosis H(37)Rv with a molecular weight (M) of 43,894, a iso-potential point of 5.25 and a score of 183. No mutation was found in the 1,440 bp encoding sequence in various strains. CONCLUSIONS: The hypothetical protein Rv0341 is related to the rifampin-dependent strains, so it can be regarded as an indicator for rifampin-dependent Mycobacterium tuberculosis. Rifampin upregulated the expression of Rv0341 in rifampin-dependent Mycobacterium tuberculosis. Whether the hypothetical protein Rv0341 is related to virulence and synthesis of the cell wall of Mycobacterium tuberculosis needs further study.

[Protein profiling of human dendritic cells infected with mycobacterium tuberculosis].

The response of dendritic cells (DCs) plays an essential role in the initiation of immune responses following Mycobacterium tuberculosis (MTB) challenge. Two-dimensional electrophoresis (2-DE) was employed to compare the global protein patterns between human DCs infected and that uninfected with MTB H37Rv ATCC 27294 strains, and 45 protein spots were found to express differentially. Four protein spots which remarkably changed in DCs infected with MTB H37Rv ATCC 27294 strains were measured by matrix assisted laser desorption/ionization tandem time-of-flight (TOF/TOF) mass spectrometry. The data obtained from peptide mass fingerprinting were used in protein database search. Four protein spots in gel were identified as Human Arsenite-stimulated ATPase (hASNA-I), Annexin IV, gamma-actin and Heat shock protein27 (HSP27). These data provide insight into the changed global protein patterns of the DCs after infection and may prove useful for further study in the interaction between MTB and host.