2-Methoxyestradiol (2-ME2) induces leukemia cells to undergo apoptosis in association with Bcl-2 inactivation but the mechanisms whereby Bcl-2 contributes to protection against programmed cell death in this context remain unclear. Here we showed that 2-ME2 inhibited the proliferation of Jurkat leukemia cells by markedly suppressing the levels of cyclins D3 and E, E2F1 and p21(Cip1/Waf1) and up-...

Protein tyrosine phosphatases (PTPases) play an important role in regulating cell growth and transformation. We report that the antitumor agent gallium nitrate is a potent inhibitor (concentration producing 50% inhibition, 2-6 microM) of detergent-solubilized cellular membrane PTPase from Jurkat human T-cell leukemia cells and HT-29 human colon cancer cells. This is the first report of a select...

Proteolysis is a regulatory step in many physiological processes, but which proteases in what cellular sites are involved in activation or degradation of which peptides is not well known. We developed a rapid assay consisting of living cells and fluorogenic protease substrates to determine which bioactive peptides are possible natural substrates of a specific protease with the multifunctional o...

The DNA-damaging agent bleomycin arrests the cell cycle at the G2 phase of Jurkat cells defective in the G1 checkpoint, and microtubule-acting colchicine arrests it at the M phase. Boromycin itself, an actinomycete metabolite, showed no effect on the cell cycle status of Jurkat cells at least up to 340 nM. However, the compound (3.4-340 nM) was found to abrogate bleomycin-induced G2 arrest even...

Pharmacological properties of the human P2Y1 receptor transfected in Jurkat cells and of the endogenous receptor in rat brain capillary endothelial cells were analyzed under conditions in which the purity of adenine triphosphate nucleotides was controlled by creatine phosphate/creatine phosphokinase (CP/CPK). ATP, a partial agonist of the receptor, was inactive in the presence of CP/CPK. Result...

Phosphatase and tensin homolog deleted on chromosome 10 (PTEN), a multifunctional tumor suppressor, has been shown to play a regulatory role in cell migration. Dictyostelium discoideum cells lacking PTEN exhibited impaired migration toward chemoattractant gradients. In the present study, we investigated the involvement of PTEN in chemotaxis of mammalian cells by examining PTEN-null Jurkat T cel...

The tec family kinase, inducible T cell tyrosine kinase (Itk), is critical for both development and activation of T lymphocytes. We have found that Itk regulates TCR/CD3-induced actin-dependent cytoskeletal events. Expression of Src homology (SH) 2 domain mutant Itk transgenes into Jurkat T cells inhibits these events. Furthermore, Itk(-/-) murine T cells display significant defects in TCR/CD3-...

NF-kappa B plays a key role in the production of cytokines in inflammatory diseases. The effects of a novel T cell-specific NF-kappa B inhibitor, SP100030, were evaluated in cultured Jurkat cells and in murine collagen-induced arthritis (CIA). Chemical libraries were screened for NF-kappa B-inhibitory activity. SP100030, a compound identified in this process, inhibited NF-kappa B activation in ...

The response of the human Jurkat T cell leukemia-derived cell line (Jurkat T cells) after 24 h of in vitro exposure to a titanium substrate (12 × 12 × 1 mm³) with a bilateral rough (Ra = 2.2-3.7 μm) titanium oxide coating (rTOC) applied using the micro-arc method in a 20% orthophosphoric acid solution was studied. A 1.5-fold down-regulation of hTERT mRNA expression and decreases in CD3, CD4, CD...

Chronic lymphocytic leukemia (CLL) is the most commonly observed adult hematological malignancy in Western countries. Despite the fact that recent improvements in CLL treatment have led to an increased percentage of complete remissions, CLL remains an incurable disease. Cerrena unicolor is a novel fungal source of highly active extracellular laccase (ex-LAC) that is currently used in industry. ...