alpha-chymotrypsin and Leukemia

The aim of this study is to clarify the efficacy of proteasome inhibitor bortezomib to multidrug resistant (MDR) acute leukemia cells. We observed the effects of bortezomib on a P-glycoprotein (P-gp) positive leukemia line K562/A02. The results showed that bortezomib has significant effects on P-gp positive K562/A02 cells including cytotoxicity (48 h IC(50): 171.36 nM), induction of apoptosis (31.71 +/- 1.07% apoptotic cells after 24 h treatment at 100 nM), and inhibition of proteasome chymotrypsin-like activity (relative activity to untreated controls: 20.07 +/- 0.66% at 24 h with 10 nM bortezomib). These effects were lower than those observed in K562 cells (IC(50), percentage of apoptotic cells, relative chymotrypsin-like activity to untreated controls were 56.28 nM, 77.95 +/- 0.35%, 5.35 +/- 2.05% after the same treatments, respectively). No synergy between daunorubicin and bortezomib was shown in the killing of K562/A02 cells (synergistic ratios were <1). P-gp expression levels did not decrease in K562/A02 cells after bortezomib treatment. Pretreatment with bortezomib does not improve the intracellular anthracycline concentration in K562/A02 cells. Bortezomib shows a promising effect for the treatment of refractory/relapsed leukemia, but it does not improve the effect of anthracycline to MDR leukemia cells.

Topics: Apoptosis; ATP Binding Cassette Transporter, Subfamily B, Member 1; Boronic Acids; Bortezomib; Chymotrypsin; Drug Resistance, Multiple; Drug Resistance, Neoplasm; Humans; Inhibitory Concentration 50; K562 Cells; Leukemia; Pyrazines

We evaluated whether the proteasomal chymotrypsin-like (ChT-L) activity is increased in plasma of patients with acute lymphoblastic (ALL), acute myeloblastic (AML) and chronic lymphocytic (CLL) leukemias.. The activity was assayed using the fluorogenic peptide substrate in the presence of an artificial activator sodium dodecyl sulfate (SDS) in the plasma of healthy donors (n=15) and ALL (n=15), AML (n=28) and CLL (n=22) patients.. The activity was significantly (P<0.001) higher in the plasma of ALL and AML patients at the diagnosis than in healthy subjects and decreased after therapy or remained unchanged or rose during relapse. By contrast, in CLL patients at the diagnosis, the activity did not differ significantly from the healthy controls. In each group, the activity positively correlated with the serum lactic dehydrogenase activity.. Plasma proteasome ChT-L activity can be a useful bio-marker for patients with acute leukemia at the blast stage.

Topics: Adolescent; Adult; Aged; Case-Control Studies; Chymotrypsin; Female; Humans; Hydrolysis; L-Lactate Dehydrogenase; Leukemia; Leukemia, Lymphocytic, Chronic, B-Cell; Leukemia, Myeloid, Acute; Male; Middle Aged; Oligopeptides; Precursor Cell Lymphoblastic Leukemia-Lymphoma; Proteasome Endopeptidase Complex; Proteasome Inhibitors; Protein Subunits; Sodium Dodecyl Sulfate

A heterodimeric 13.8 kDa napin-like polypeptide has previously been isolated from Chinese cabbage (Brassica parachinensis) seeds with a procedure involving ion exchange chromatography on DEAE-cellulose, affinity chromatography on Affi-gel blue gel, FPLC-ion exchange chromatography on Mono S and FPLC-gel filtration on Superdex 75. In the present study the N-terminal sequence of the 8.8 kDa subunit of the polypeptide (PQGPQQRPPKLLQQQTNEEHE) was found to have pronounced homology to napins, albumins and trypsin inhibitors, but demonstrated little similarity to the 5 kDa subunit. The polypeptide stimulated nitrite production by mouse peritoneal macrophages and reduced the viability of leukaemia (L1210) cells. It inhibited trypsin with a higher potency than it inhibited chymotrypsin, but was devoid of ribonuclease and antifungal activities.

Topics: Amino Acid Sequence; Animals; Brassica; Cell Division; Cell Line, Tumor; Chymotrypsin; Leukemia; Lipopolysaccharides; Macrophages; Mice; Molecular Sequence Data; Nitrates; Peptides; Plant Proteins; Seeds; Sequence Homology, Amino Acid; Trypsin; Trypsin Inhibitors

LiCl interacts synergistically with all-trans-retinoic acid, promoting the terminal differentiation of WEHI-3B D(+) cells, a phenomenon partially due to the ability of the monovalent lithium cation to inhibit the proteasome-dependent degradation of retinoic acid receptor alpha protein. In this report, the 20S proteasome was purified from WEHI-3B D(+) cells and the effects of LiCl on chymotrypsin-like (Chtl) activity and peptidyl-glutamyl peptide hydrolyzing (PGPH) activity were determined. LiCl functions to inactivate both proteasomal activities in a time-dependent manner, without affecting non-proteasomal proteases. The half-lives for inactivation of Chtl and PGPH hydrolyzing activities were approximately 23 and 36min, respectively, at 10mM LiCl. Both SDS and peptide substrate increased the rate of inactivation. Partial enzymatic activity was recovered after dialysis in the absence of SDS, indicating that the off-rate for lithium was extremely slow. The findings suggest that the inactivation of Chtl and PGPH activities by LiCl occurs through a proteasomal conformational change.

Topics: Animals; Chymotrypsin; Cysteine Endopeptidases; Cysteine Proteinase Inhibitors; Kinetics; Leukemia; Lithium Chloride; Multienzyme Complexes; Proteasome Endopeptidase Complex; Tumor Cells, Cultured

Lithium affects several enzymatic activities, however, the molecular mechanisms of lithium actions are not fully understood. We previously showed that LiCl interacts synergistically with all-trans-retinoic acid to promote terminal differentiation of WEHI-3B D(+) cells, a phenomenon accompanied by the recovery of the retinoid-induced loss of retinoic acid receptor alpha protein pools. Here, we demonstrate the effects of LiCl on proteasome-dependent degradation of retinoic acid receptor alpha proteins. LiCl alone, or in combination with all-trans-retinoic acid, increased cellular levels of ubiquitinated retinoic acid receptor alpha and markedly reduced chymotryptic-like activity of WEHI-3B D(+) 20 S and 26 S proteasome enzymes. Neither KCl nor all-trans-retinoic acid affected enzyme activity, whereas NaCl produced a modest reduction at relatively high concentrations. In addition, LiCl inhibited 20 S proteasome chymotryptic-like activity from rabbits but had no effect on tryptic-like activity of the 26 S proteasome. This effect has significant consequences in stabilizing the retinoic acid receptor alpha protein levels that are necessary to promote continued differentiation of leukemia cells in response to all-trans-retinoic acid. In support of this concept, combination of proteasome inhibitors beta-clastolactacystin or benzyloxycarbonyl-Leu-Leu-Phe with all-trans-retinoic acid increased differentiation of WEHI-3B D(+) cells in a manner that was analogous to the combination of LiCl and all-trans-retinoic acid.

Topics: Adjuvants, Immunologic; Animals; Blotting, Western; Cell Differentiation; Cell Line; Chymotrypsin; Cysteine Endopeptidases; Humans; Kinetics; Lactones; Leukemia; Lithium Chloride; Multienzyme Complexes; Oligopeptides; Peptide Hydrolases; Precipitin Tests; Proteasome Endopeptidase Complex; Protein Binding; Protein Biosynthesis; Rabbits; Receptors, Retinoic Acid; Retinoic Acid Receptor alpha; Time Factors; Tretinoin; Trypsin; Tumor Cells, Cultured; Ubiquitin

Activity of a chymotrypsin-type serine protease was found in a subline of rat basophilic leukemia (RBL-2H3) cells. The protease was immunologically cross-reactive with anti-atypical mast cell protease immunoglobulin (Ig) G, and its activity was inhibited in a dose-dependent manner by the antibody. The apparent m.w. of the protease that reacted with the antibody was 25,000, which was identical with that of atypical mast cell protease in rat mucosal mast cells. These results show that the chymotrypsin type serine protease in RBL-2H3 cells is immunologically identical with atypical mast cell protease, which was first purified from rat small intestine. Immunohistochemical studies showed that the protease was located not only in intracytoplasmic granules but also in organelles synthesizing protein, such as cisternae of the rough endoplasmic reticulum, perinuclear spaces, and the Golgi apparatus. However, no immunoreactivity was demonstrated in rat basophils. The activity of the protease increased in the exponential phase of growth of RBL-2H3 cells in which some activity was also detected in the medium, and it decreased in the late stationary phase.

Topics: Animals; Basophils; Cell Line; Chymases; Chymotrypsin; Cross Reactions; Endopeptidases; Histocytochemistry; Immunoglobulin G; Leukemia; Male; Mast Cells; Rats; Rats, Inbred Strains; Serine Endopeptidases; Staining and Labeling

Partially purified IgE receptor(s) of rat basophilic leukemia cells (RBL) designated R and H and having apparent molecular weight of 45,000 and 55,000 daltons, respectively, were subjected to proteolysis with papain. Polyacrylamide gel electrophoresis of the digests in the presence of sodium dodecyl sulfate revealed a difference in the size and number of the fragments produced. These results suggest that these two receptor molecules are different with respect to amino acid composition and sequence. Whole Nonidet P-40 extracts of RBL cells were also subjected to digestions with papain, trypsin and chymotrypsin in an attempt to obtain receptor fragments still capable of binding to IgE-Sepharose. Treatment with papain produced a 38,000 dalton fragment of H but no fragments of R which retained the ability to bind to IgE. Tryptic and chymotryptic treatment produced a 41,000 dalton fragment of H with affinity for IgE. The IgE-binding site of R was either destroyed or not affected at all.

Topics: Animals; Basophils; Cells, Cultured; Chymotrypsin; Electrophoresis, Polyacrylamide Gel; Leukemia; Molecular Weight; Papain; Peptide Fragments; Rats; Receptors, IgE; Receptors, Immunologic; Trypsin

Topics: Acute Disease; Blood Coagulation Disorders; Chymotrypsin; Granulocytes; Humans; Leukemia; Leukocytes; Pancreatic Elastase; Peptide Hydrolases; Sepsis

Topics: Antigens; Chymotrypsin; Enzyme Precursors; Humans; Leukemia; Leukemia, Myeloid; Spleen

A method for the isolation of metaphase chromosomes from mouse L1210 leukemia cells has been developed. Cells, arrested at metaphase with colchicine, were exposed to hypotonic solution and the pH was then adjusted to 5.6 to stabilize the chromosomes. The metaphase figures were subsequently disrupted and the chromosomes isolated by a series of differential centrifugations in sucrose. The isolated chromosomes were well preserved, as judged by morphological criteria. The effect of various enzymes and chemical agents on the isolated chromosomes was studied. Chymotrypsin, trypsin, and deoxyribonuclease caused a marked disintegration of the chromosomes, whereas treatment with pepsin and ribonuclease induced no significant morphological alterations.

Topics: Centrifugation; Chromosomes; Chymotrypsin; Colchicine; Deoxyribonucleases; DNA; Leukemia; Leukemia, Experimental; Lymphocytes; Metaphase; Mice; Pepsin A; Pharmacology; Research; Ribonucleases; Trypsin