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Biomedical subjects

L Kaczmarek

Publications and source records attributed to L Kaczmarek.

At least 127 records · Page 7Linked to original sources
PubMed1986

Altered expression of G1-specific genes in human malignant myeloid cells.

We have studied the expression of cell-cycle genes specific to the G1 (2A9, 2F1, 4F1, c-myc) and S (histone H3) phases of the cell cycle in normal and malignant human myeloid cycling cells. The levels of expression were determined by measuring the amounts of specific RNA in blot hybridization assays. Levels of expression of the G1 genes were compared to the level of expression of the S-phase-specific H3 gene. This method can distinguish whether an increased expression of G1 genes is truly due to deregulation or simply reflects an increase in the fraction of proliferating cells. In a normal asynchronous system provided by the bone marrow cells of three normal donors, the expressions of the four G1-specific genes 2A9, 2F1, 4F1, and c-myc, and of the S-phase-specific gene H3 were in ratios that differed little from one individual to another. In the total RNA of eight patients in the chronic phase of chronic myelogenous leukemia, a high level of expression of G1 cell-cycle genes was paralleled by a high level of expression of the S-phase H3 gene, simply reflecting an increase in the fraction of proliferating cells. In patients with acute myelogenous leukemia (AML), the RNA levels of 2F1 and 4F1 paralleled the expression of H3-i.e., the ratios of expression 2F1/H3 and 4F1/H3 were the same as in normal bone marrow cells. However, in 9 of 10 patients with AML we found that the expression of c-myc was elevated with respect to H3 expression. The expression of 2A9 (with respect to H3) was also elevated in some of these AML patients. Two important conclusions can be drawn from these findings: increased levels of a G1-specific RNA in a tumor may not indicate overexpression of that gene but may instead simply reflect the fraction of proliferating cells; and in some patients with AML, however, the expression of certain G1 genes is truly deregulated and might contribute to the impairment of proliferative control that is associated with this phenotype.

Cell Cycle↗
PubMed1986

Coding sequence and growth regulation of the human vimentin gene.

We have established the complete coding sequence of the human vimentin gene. It had 91% homology to the coding sequence of the Syrian hamster vimentin gene (Quax et al., Cell 35:215-223, 1983) and partial homology to several other sequences coding for intermediate filament proteins. The most striking difference between the Syrian hamster and human vimentin genes was in the 3' untranslated region, which was considerably longer in the Syrian hamster. Using RNA blots and a human vimentin cDNA clone from an Okayama-Berg library, we have established that expression of the vimentin gene was growth regulated. The steady-state levels of cytoplasmic vimentin mRNA in 3T3 cells were increased by serum and platelet-derived growth factor, but not by epidermal growth factor, insulin, or platelet-poor plasma. The increase in expression of the vimentin gene that occurred when G0-phase cells were stimulated to proliferate was detected in six different cell types from four different species. The expression of the vimentin gene was also increased when HL60 cells were induced to differentiate by phorbol esters; it decreased when differentiation was induced by retinoic acid.

Amino Acid Sequence↗
PubMed1986

Growth-dependent expression of human Mr 53,000 tumor antigen messenger RNA in normal and neoplastic cells.

We have investigated the expression of Mr 53,000 protein (p53) in total RNA isolated from human peripheral blood mononuclear cells stimulated by phytohemagglutinin, in serum-stimulated human diploid fibroblasts, and in normal and tumor cells of human epithelial colon tissue. We have found that the expression of p53 messenger RNA is growth regulated in human cells following kinetics similar to that previously shown in mouse 3T3 cells, and is increased in the large majority of colon adenocarcinomas in comparison to adjacent normal mucosa and adenoma. This increased expression of p53 is accompanied by a nearly proportional increase in the expression of histone H3. As the expression of histone H3 is restricted to the S phase of the cell cycle and therefore measures the growth fraction of a given population, we suggest that the increased expression of p53 observed in the large majority of colon tumors simply reflects the increased number of cycling cells frequently found in a neoplastic tissue. At variance with these findings a true overexpression of p53 was detected in one SV40-transformed human fibroblasts cell line.

Adenocarcinoma↗
PubMed1986

Structure-activity relationship studies on selected iso-alpha-carbolines. I.

In the course of microbial transformation of the antitumor compounds, it has been found that iso-alpha-carbolines and their certain derivatives undergo N-1 methylation by Kitasatosporia setae. The resulting products, iso-alpha-carbolines exhibit antibacterial and antifungal properties in the concentration range of 0.2-2.5 mumol/ml. In the cytotoxicity test only derivatives substituted at C-2 and C-4 display moderate activity against KB cells. None of the compounds tested show a significant inhibitory effect against P388 lymphocytic leukemia.

Actinomycetales↗
PubMed1986

Antineoplastic activity of azacarbazoles. I. Synthesis and antitumor properties of alpha-carboline and its selected derivatives.

alpha-Carboline and its several derivatives have been synthesized and evaluated for their antitumor activity against L1210 lymphoid leukemia, P388 lymphocytic leukemia and Sarcoma 180. It was found that of these compounds only alpha-carboline and its derivatives substituted in C-4 position with a methyl group or in 6-C position with a methyl group and fluorine or chlorine atoms caused moderate inhibition of the tumor growth of Sarcoma 180. The introduction of bromide, iodide atoms, hydroxy-, amino-groups or some other substituents in C-6 position of alpha-carboline molecule reduced significantly the biological activity of the tested compounds against Sarcoma 180. Additionally, the introduction of an ethyl or ethoxycarbonyl group to the pyrrole ring at N-9 also obliterated antitumor properties of these analogues. None of the tested compounds displayed a significant activity against murine leukemias. In the cytotoxicity test of KB cells all the compounds were inactive.

Animals↗
PubMed1986

Antineoplastic activity of azacarbazoles. III. Synthesis and antitumor evaluation of selected 2-, 3- aza- and diazaanalogues of carbazole.

Preliminary screening of the antitumor properties of selected azacarbazoles revealed that of all the compounds tested only 2,7-diazacarbazole (compound IX) and 3,6-diazacarbazole (compound XI) caused the inhibition of Sarcoma 180 growth up to 70%. beta- and gamma-Carbolines and their derivatives in presented testing system were inactive. None of the tested compounds displayed marked activity against murine leukemias and was active in the cytotoxicity test of KB cells.

Animals↗
PubMed1986

Expression of growth-regulated genes in human acute leukemias.

We have investigated the expression of six growth-regulated genes (c-myc, c-myb, p53, 4F1, 2F1, and ornithine decarboxylase) and the S-phase-specific histone H3 gene in acute myeloid and lymphoid leukemic cells. We have purposely chosen three growth-regulated protooncogenes that share similar biological features and three gene sequences that have in common the cell cycle dependence of their expression in cells of different tissue and in different species. The level of expression was determined by measuring the amounts of specific RNA by Northern blot analysis. Levels of expression of the six growth-regulated genes were compared to the level of expression of the S-phase-specific H3 gene and among themselves. This method distinguishes the increased expression of a growth-regulated gene due to a true altered activation from over-expression which simply reflects an increase in the fraction of cycling cells. We have found that six of 14 patients with acute leukemias have markedly high ratios of c-myc/H3, c-myc/p53, and c-myc/c-myb expression. Two patients with altered c-myc expression have also a high ratio p53/H3. Within the group of cell cycle-dependent genes the ratios of expression seem in the overall much more regular with the clear exception of a patient with acute myelogenous leukemia in which the ratios 4F1/H3 and 2F1/H3 are significantly increased. A possible interpretation of these findings is that the fraction of noncycling leukemic cells that often constitute the majority of the entire leukemic population is in some cases in a true resting state, whereas in other cases heterogeneous degrees of growth arrest might occur. The altered expression of c-myc seems the feature most commonly associated with this putative growth arrest of leukemic cells suggesting that this gene may contribute to the impairment of proliferative control that is associated with the leukemic phenotype.

Acute Disease↗
PubMed1985

Effect of interleukin-2 on the expression of cell cycle genes in human T lymphocytes.

We have studied the expression of seven cell cycle-dependent genes in phytohemagglutinin (PHA)-stimulated peripheral blood mononuclear cells, in macrophage-depleted cultures and in macrophage-depleted cultures plus Interleukin-2 (IL-2). The expression of all seven genes is increased in PHA stimulated peripheral cells. Only two (2F1 and the IL-2 receptor) are increased in PHA-stimulated macrophage depleted cultures. Addition of IL-2 to these cultures increased the RNA levels of four genes (KC-1, c-myc, beta-actin and IL-2R), but has no effect on three others (4F1, 2F1, and JE-3). The results indicate that the expression of these cell cycle genes is regulated by different components of the mitogenic stimulus.

Autoradiography↗
PubMed1985

Microinjected c-myc as a competence factor.

While a number of oncogenes are expressed in a cell cycle-dependent manner, their role in the control of cell proliferation can only be established by a direct functional assay. The c-myc protein, upon microinjection into nuclei of quiescent Swiss 3T3 cells, cooperated with platelet-poor plasma in the stimulation of cellular DNA synthesis. This suggests that c-myc protein, like platelet-derived growth factor (PDGF), may act as a competence factor in the cell cycle to promote the progression of cells to S phase. The presence in the medium of an antibody against PDGF abolished DNA synthesis induced by microinjected PDGF; however, the microinjected c-myc protein stimulated DNA synthesis even when its own antibody was present in the medium. The c-myc protein may act as an intracellular competence factor, while PDGF expresses its biological activity only from outside the cells.

Animals↗
PubMed1985

Cell-cycle-specific genes differentially expressed in human leukemias.

Three cDNA clones isolated from Syrian hamster cells (p4F1, p2F1, and p2A9) contain sequences that are preferentially expressed in the G1 phase of the cell cycle. The expression of these sequences was investigated in human peripheral blood cells from normal individuals and from patients with leukemia. The expression of p4F1 and p2F1 is clearly dependent on the cell cycle in peripheral blood mononuclear cells stimulated to proliferate with phytohemagglutinin; the p2A9 sequences cannot be clearly detected in human lymphocytes but are expressed in a cell-cycle-dependent manner in human diploid fibroblasts (WI-38). These genes also show different levels of expression in lymphoid and myeloid leukemias. The highest level of expression for p2A9 is found in patients with chronic myelogenous leukemia, and the lowest in patients with chronic lymphocytic leukemia. For p2F1 and p4F1, the highest levels of expression are found in chronic and acute myelogenous leukemia. At least two other cell-cycle genes are not expressed at detectable levels in human leukemias. These findings suggest that the activation of cell-division-cycle genes might contribute, like cellular oncogenes, to the phenotype of human malignancies and that, perhaps, new oncogenes could be found by identifying and isolating genes whose expression is dependent on the cell cycle.

Cell Cycle↗
PubMed1985

Expression of cell-cycle-dependent genes in phytohemagglutinin-stimulated human lymphocytes.

We have investigated the expression of certain cell-cycle-dependent genes in human peripheral blood mononuclear cells (PBMC) stimulated by phytohemagglutinin (PHA). The genes studied had been previously identified as cell-cycle dependent in other cell types from different species and were induced by different mitogens. One of these genes (2F1) and the gene for the interleukin 2 receptor were induced by PHA even in cultures partially depleted of accessory cells where the lymphocytes grew in size but failed to enter S phase. The other genes (c-myc, 4F1, JE-3, and KC-1) were induced only in complete cultures of PBMC stimulated by PHA. These results confirm the dissociation between growth in size and cell DNA replication that can occur during cell-cycle progression. Moreover, the time course of appearance of detectable levels of RNA for these genes suggests that they may be used as markers of cell-cycle progression in the transition of lymphocytes from G0 to S phase.

Cell Cycle↗
PubMed1985

Expression of c-myc and other cell cycle-dependent genes in human colon neoplasia.

We have investigated the expression of certain cell cycle-dependent genes in total RNA isolated from normal and neoplastic cells of human epithelial colon tissue. The genes studied had been previously identified as cell cycle dependent in rodent and human fibroblasts. Levels of expression of G1 genes were compared to the level of expression of the S-phase-specific gene H3 in normal and adjacent neoplastic epithelial cells of six different individuals. We have found that the increase in the expression of c-myc gene detected in colon tumor cells is accompanied by a parallel increase in the expression of two G1-specific genes (p2A9 and ornithine decarboxylase) and the S-phase-specific gene histone H3. An important conclusion that can be drawn from these findings is that the increased level of a cell cycle-specific RNA in a tumor may not indicate overexpression of that gene but simply reflect the increased fraction of cycling cells, unless the ratio of expression between G1 genes and G1-S-phase genes is altered.

Adenocarcinoma↗
PubMed1985

Biological activity of 1,4-dihydropyridine derivatives.

Six new 1,4-dihydropyridine derivatives were evaluated in vitro for antimicrobial and cytotoxic effects and in vivo for antineoplastic activity. These compounds inhibited the growth of most of Gram-positive and Gram-negative bacteria at concentrations of 50 and 100 micrograms/ml. Concentrations effective against fungi were somewhat lower (25-50 micrograms/ml). The growth of mycobacteria was inhibited at concentrations of 3.1-25 micrograms/ml. Compound IV inhibited the growth of pathogenic mycobacteria including M. tuberculosis resistant to SM and INH at 3.1 or 6.2 micrograms/ml. In cytotoxicity assays, compound II, IV and V appeared the most active. However, none of the 1,4-dihydropyridine derivatives affected the survival time of mice with P388 and L1210 leukemias or melanoma B16. The growth of subcutaneous tumors of sarcoma 180 was inhibited by compounds I, III, IV and V. The effect was dose related.

Animals↗
PubMed1984

Hematological characterization of anemic mice homozygous for S1 allele at steel locus.

Adult S1/S1 mice when compared to normal +/+ littermates suffer from macrocytic anemia with normal absolute reticulocyte count and leukopenia. Femoral marrow cellularity is reduced two-fold with increased frequency of benzidine-positive (erythroblastic) and decreased frequency of peroxidase-positive (granulocytic) cells. The relationships are reversed in the spleen, where total cellularity is normal. CFU-S cells from S1/S1 mice from equivalent numbers of exogenous spleen colonies in lethally irradiated recipients to CFU-S from +/+ mice. Moreover, there is a similar cellular composition in these colonies. However, marrow cells from S1/S1 mice form twice reduced numbers of erythroblastic bursts in diffusion chambers and the formation of early erythrocytic colonies (CFU-E-derived) in diffusion chambers is reduced nearly ten times in the case of S1/S1 marrow cells. Endogenous spleen colony formation is nearly absent in S1/S1 mice following 100 cGy of X-irradiation both at 5 and 10 post-irradiation days. In +/+ mice, hemopoietic regeneration of the spleen following this dose is abundant. In conclusion, S1/S1 mice possess similar but slightly more severe defects of hemopoiesis than S1/S1d mice. As can be seen in the latter model this is dependent on altered hemopoietic environment in S1/S1 animals.

Alleles↗
PubMed1983

Osteopetrosis associated with premature thymic involution in grey-lethal mice. In vitro studies of thymic microenvironment.

The thymic atrophy developed in osteopetrotic grey-lethal (gl/gl) mouse during the last 10 days of life, and at 35 days of life gl/gl mice had only a few million thymic cells. Maximal survival of gl/gl mice was about 40 days. Earlier, at 20 days of age despite the presence of all signs of osteopetrosis their thymus had normal cellularity. This change in thymus cellularity was associated with relative increase in the frequency of cells forming thymic non-lymphoid (stromal) colonies in vitro. There were no qualitative differences in the presence of major cell types i.e. fibroblastoid, epithelioid and macrophages normally observed in these colonies. However, giant multinucleated cells resembling macrophages in size and appearance of nuclei were observed exclusively in cultures of the thymus from 20 day old control mice and not in cultures of gl/gl mice. On the other hand, in cultures of the thymuses of 35 day old gl/gl mice giant cells were observed that were nearly absent in cultures of the thymuses of control mice. These cells were either polynuclear or their nuclei were segmented and they resembled rather nuclei of epithelioid and fibroblastoid cells than nuclei of macrophages. The significance of all these findings is discussed.

Aging↗
PubMed1981

Characterization and biological activity of cloned simian virus 40 DNA fragments.

The biological activity of fragments of the SV40 genome was determined by manual microinjection of the fragments into the nuclei of mammalian cells. Fragments of the SV40 A gene (that codes for the T antigens) were obtained either directly by digestion with restriction endonucleases or after cloning into plasmid pBR322. Three different biological activities were studied: expression of T antigen, induction of cell DNA synthesis, and, in a few cases, reactivation of repressed ribosomal RNA genes. By using a number of fragments with deletions in the various portions of the SV40 A gene, we have been able to conclude that: 1) the sequences from 0.65 to 0.51 map units are not needed for the induction of cell DNA synthesis; 2) the sequences from 0.42 to 0.17 map units are not needed for the induction of cell DNA synthesis; and 3) the critical sequences for the induction of cell DNA synthesis, 0.51 to 0.42 map units, are different from those necessary for the reactivation of repressed ribosomal RNA genes (0.39-0.33 map units). These results indicate that the information for these two fundamental processes of cell proliferation resides in two separate and distinct domains of the SV40 A gene.

Animals↗