Acute ifosfamide-induced proximal tubular toxic reaction.
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Biomedical subjects
Publications and source records attributed to E Sariban.
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Bone marrow grafts of 5 patients with stage IV neuroblastoma and one patient with stage IV retinoblastoma were harvested during complete remission and in vitro processed for autologous transplantation. Because of the risk to reinfuse metastatic cells, the grafts were immunomagnetically purged. After preparation of the buffy coat fraction, mononuclear cells (mnc) and progenitor cells (CFU-GM) were enriched by density centrifugation and incubated successively with a cocktail of five tumour reacting monoclonal antibodies and magnetic microparticles. Target cells were removed by a set of samarium cobalt magnets. The purged grafts were stored in liquid nitrogen. After the complete procedure, an average of 16% nucleated cells of the initial harvest could be recovered. This corresponds with a mean number of 0.5 X 10(8) mnc and 2.4 X 10(4) CFU-GM per kg body weight being available for grafting. So far, 5 patients received their purged marrow graft and showed a sustained take.
We reported previously that Ets2 is expressed in normal and transformed macrophages. We show here that the expression of both c-ets-2 mRNA proteins is induced rapidly and transiently in chicken nondividing bone marrow-derived macrophages but not in E26-transformed myeloblasts in response to chicken myelomonocytic growth factor (cMGF), an avian hematopoietic growth factor required for survival, proliferation, and colony formation of avian myeloid cells. c-ets-2 expression is also rapidly induced in chicken bone marrow-derived macrophages, human monocytes, and mouse peritoneal macrophages in response to LPS and/or PKC activators. The rapid induction of Ets2 after treatment of chicken bone marrow-derived macrophages by cMGF is blunted after down-regulation or inactivation of PKC, suggesting a role of PKC in the cMGF-induced signal transduction pathway. Because Ets2 is localized in the nucleus of macrophages and binds to DNA in vitro, the kinetics of its expression suggest a role for Ets2 in the transduction within the nucleus of specific signals received at the cell membrane and involved in securing the survival and/or the development of functional competence of these cells.
Five cases of central diabetes insipidus demonstrate the potential of MRI to explore the hypothalamohypophysial axis. The diversity of the detected pathologies are illustrated: abnormal signal of the posterior pituitary in an idiopathic diabetes insipidus, lobar prosencephaly, malignant teratoma (embryonal carcinoma), histiocytosis X, craniopharyngioma.
The colony-stimulating factor-1 (CSF-1) regulates survival, growth, and differentiation of monocytes by binding to a single class of high-affinity receptors. The CSF-1 receptor is identical to the product of the c-fms protooncogene. The present studies monitored the effects of TPA and CSF-1 on c-fms gene expression in human monocytes. The results demonstrate that TPA downmodulates the constitutive expression of c-fms mRNA to low but detectable levels. Treatment of human monocytes with TPA was similarly associated with decreases in levels of the 138- and 125-Kd c-fms-encoded proteins. However, the kinetics of c-fms protein downmodulation indicated independent effects of TPA on c-fms expression at the RNA and protein levels. Furthermore, c-fms protein levels subsequently recovered despite persistently low levels of c-fms mRNA. Although previous studies demonstrated that c-fms protein is down-regulated in the presence of CSF-1, the present results indicate that CSF-1 also downregulates levels of c-fms mRNA. Moreover, the results indicate that CSF-1 increases protein kinase C activity in the membrane fraction. Together, these findings suggest that c-fms gene expression is differentially regulated at both the RNA and protein levels after activation of protein kinase C in human monocytes treated with TPA and CSF-1.
Platelet-derived growth factor (PDGF), a potent mitogen for mesenchymal cells, consists of PDGF-1 and PDGF-2 polypeptide chains which are linked by disulfide bonds. Sequence analysis has revealed that: (a) the PDGF-2 chain is encoded by the c-sis protooncogene, the cellular counterpart of the simian sarcoma viral oncogene; (b) the PDGF-1 and PDGF-2 chains are related; and (c) the PDGF-1 gene has no known viral homologue. We have previously shown that the PDGF-2 gene is expressed during 12-O-tetradecanoylphorbol-13-acetate (TPA) induced monocytic differentiation of human HL-60 leukemia cells. In the present study, PDGF-1 and PDGF-2 gene expression was compared in HL-60 cells, human THP-1 monocytic leukemia cells, and human monocytes. Uninduced HL-60 cells, uninduced THP-1 cells, and resting monocytes had no detectable PDGF-1 or PDGF-2 mRNA. In contrast, both PDGF-1 and PDGF-2 transcripts were detected in HL-60 cells and monocytes induced with TPA, while only PDGF-1 mRNA was found in TPA-treated THP-1 cells. Moreover, neither of these transcripts were found during drug induced granulocytic differentiation of HL-60 cells. Cycloheximide, an inhibitor of protein synthesis: (a) failed to increase PDGF-1 and PDGF-2 mRNA levels in uninduced HL-60 cells; (b) increased PDGF-2, but not PDGF-1, mRNA in resting monocytes; and (c) increased levels of PDGF-1 and PDGF-2 mRNA in HL-60 cells and monocytes treated with TPA. This effect of cycloheximide was related in part to stabilization of both transcripts. Thus, PDGF-1 and PDGF-2 genes are differentially regulated in myeloid cells, although they share common control mechanisms at the post-transcriptional level. Differential regulation of PDGF gene expression would result in altered chain composition of the PDGF protein and possibly changes in biological activity.
Prostate carcinoma cell lines DU-145 and PC-3 express both platelet derived growth factor (PDGF)-1 and PDGF-2/sis genes. Concomitantly, these cells synthesize and secrete PDGF-like proteins, as judged by indirect immunofluorescence and by direct immunoprecipitation with specific PDGF antiserum. Conditioned media derived from DU-145 and PC-3 cells stimulated the incorporation of [3H]thymidine by 3T3 cells and competed with 125I-labeled PDGF for its binding to cell surface receptors of 3T3 cells. The biological activity was stable to heating at 100 degrees C for 10 min, sensitive to reducing agents, and neutralized by the IgG fraction of PDGF antiserum, properties similar to those of authentic PDGF. Both DU-145 and PC-3 cell lines appear to lack receptors for PDGF as indicated by their inability to mitogenically respond to PDGF and receptor binding of 125I-labeled PDGF. Production of PDGF-like proteins by human prostate carcinoma cells may play an important role in a paracrine mode in the organization of the extracellular matrix of the malignant tissue.
We examined the mechanisms that are responsible for the regulation of c-fos gene expression in human monocytes. Levels of c-fos mRNA were low or undetectable in resting monocytes. Results of run-on transcription assays, however, demonstrated that both the first two and last two exons of the c-fos gene were transcribed at similar rates, and that only the sense strand of this gene was transcribed. These findings suggest that the level of c-fos transcripts in resting human monocytes is controlled at a posttranscriptional level. Activation of resting monocytes with phorbol ester was associated with a rapid and transient increase in c-fos mRNA levels. This increase in c-fos transcripts was related to an enhanced rate of c-fos transcription. Moreover, exposure of resting monocytes to inhibitors of protein synthesis induced (i) a rapid and marked (300-fold) increase in c-fos mRNA levels, despite only a 9-fold increase in c-fos transcription, and (ii) a prolongation of the half-life of c-fos mRNA. Thus, while posttranscriptional control was responsible for the down-regulation of c-fos transcripts in both resting and activated human monocytes, transcriptional mechanisms were responsible for the transient increase in c-fos expression induced by phorbol ester. Furthermore, the marked increases in c-fos mRNA associated with inhibition of protein synthesis were regulated by both transcriptional and posttranscriptional mechanisms. These findings may be related to recent observations which indicate that both positive and negative factors transcriptionally regulate c-fos gene expression and that sequences found in the 3'-untranslated region of the c-fos mRNA are responsible for the stability of this transcript.
Regulation of CSF-1 gene expression was investigated in human monocytes. CSF-1 transcripts were at low or undetectable levels in resting monocytes. However, in monocytes treated with 12-O-tetradecanoylphorbol-13-acetate (TPA), CSF-1 mRNA was increased by 3 h and reached maximal levels by 12 h of drug exposure. When nuclear run-on assays were used, CSF-1 gene transcription was also at low or undetectable levels in resting monocytes but was activated after TPA exposure. TPA-treated monocytes exposed to actinomycin D further demonstrated that the half-life of the CSF-1 mRNA is 0.9 h. The results also demonstrated that the protein synthesis inhibitor, cycloheximide (CHX), increases CSF-1 mRNA levels in both resting and TPA-treated monocytes. These effects of CHX occurred in the absence of detectable increases in CSF-1 gene transcription. Moreover, treatment of monocytes with CHX and actinomycin D demonstrated that inhibition of protein synthesis is associated with stabilization of the CSF-1 transcript. Taken together, these findings indicated that CSF-1 gene expression is controlled at both transcriptional and posttranscriptional levels in human monocytes.
Tumor necrosis factor (TNF) is a monokine with in vitro cytotoxicity for some but not all tumor cells. The basis for sensitivity and resistance to the antitumor effects of this agent remains unclear. The present studies have monitored the effects of TNF on 14 epithelial tumor cell lines. Eleven of these cell lines were resistant to the growth inhibitory effects of TNF (50% inhibitory concentration greater than 1,000 U/ml). 12 of the 14 tumor cell lines has detectable levels of high affinity cell surface TNF binding sites, thus suggesting that resistance was not often due to the absence of cell surface TNF receptors. Northern blot analysis demonstrated that three of the eleven resistant cell lines expressed detectable levels of TNF mRNA. Furthermore, both sensitive and resistant epithelial tumor cells had the capacity to express TNF transcripts in the presence of the protein synthesis inhibitor, cycloheximide. Finally, the presence of TNF expression at the RNA level is shown to be associated with the production of a TNF-like protein in the resistant Ov-D ovarian carcinoma cells. These findings suggest that certain human epithelial tumor cell lines inherently resistant to TNF also express this cytokine.
Regulation of tumor necrosis factor (TNF) gene expression was investigated in resting human monocytes and in 12-O-tetradecanoylphorbol-13-acetate (TPA) activated monocytes. TNF transcripts were undetectable in resting monocytes. However, in TPA-activated monocytes, TNF mRNA was first detectable by 3 h and reached maximal levels by 12 h of drug exposure. Using run-on transcription assays, the TNF gene was transcriptionally inactive in resting monocytes, but was rapidly activated after TPA exposure. The protein synthesis inhibitor, cycloheximide (CHX), had no detectable effect on levels of TNF transcripts in resting monocytes, while this agent superinduced the level of TNF mRNA by 50-fold in TPA-activated cells. TPA activated monocytes were also exposed to actinomycin D and/or CHX to determine whether transcriptional or posttranscriptional control of TNF gene expression was responsible for the induction of TNF transcripts. After 1 h of actinomycin D treatment, the amount of TNF transcripts was reduced by 75%. In contrast, no difference in TNF mRNA levels was observed in TPA-activated monocytes exposed to CHX alone or CHX in combination with actinomycin D. These findings indicated that CHX prevented the degradation of TNF mRNA by inhibiting the synthesis of a labile protein. Run-on transcription assays performed on cells exposed to either TPA or the combination of TPA and CHX further indicated that CHX treatment increased transcription of the TNF gene. Thus, TNF gene expression is controlled at the transcriptional level in resting human monocytes, while both transcriptional and posttranscriptional events regulate the level of TNF transcripts in TPA-activated cells.
Human malignant epithelial cell lines were analyzed for expression of platelet-derived growth factor (PDGF) genes. Of the 12 cell lines tested, 9, derived from breast, lung, gastric, and ovarian carcinomas, were found to express both PDGF-1 and PDGF-2 genes. The levels of both PDGF-1 and PDGF-2 transcripts were superinduced when these cells were treated with cycloheximide, an inhibitor of protein synthesis. These cells also released an activity that in studies with BALB-c/3T3 cells, inhibited binding of 125I-labeled PDGF and stimulated incorporation of [3H]thymidine. This stimulating activity was inhibited after reduction of the conditioned media by mercaptoethanol or after preincubation with antibodies to PDGF. Moreover, this activity was not affected by heat treatment. Immunoprecipitation studies revealed that breast, lung, and gastric carcinoma cells produced PDGF-like proteins that migrated as 30- and 32-kD species under nonreducing conditions and as 15- and 16-kD species under reducing conditions. In contrast, malignant cells of ovarian origin produced 14-16-kD PDGF-like proteins that were unchanged in mobility after reduction. As PDGF receptors were not detected on these malignant epithelial cells, the production of PDGF-like proteins may affect other cells in the microenvironment by paracrine mechanisms and may contribute to excessive cell proliferation, inflammatory reactions, and connective tissue remodeling seen in certain carcinomas.
Phorbol esters induce the human HL-60 promyelocytic cell line to differentiate along a monocytic pathway. This induction of differentiation may involve phorbol ester-induced activation of the phospholipid- and calcium-dependent protein kinase C. Bryostatin 1, a macrocyclic lactone, has been shown to compete with phorbol esters for binding to protein kinase C. We have confirmed that bryostatin 1 translocates activity of protein kinase C from the cytosolic to membrane fractions of HL-60 cells. The present results also demonstrate that bryostatin 1 (10 nmol/L) induces monocytic differentiation of HL-60 cells as determined by adherence, growth inhibition, appearance of monocyte cell surface antigens, and alpha-naphthyl acetate esterase staining. Furthermore, bryostatin 1 (10 nmol/L) downregulated c-myc expression and induced c-fos, c-fms, and tumor necrosis factor transcripts. These changes in gene expression induced by bryostatin 1 are similar to those associated with phorbol ester-induced monocytic differentiation of HL-60 cells. In contrast, exposure to a higher concentration of bryostatin 1 (100 nmol/L) had less of an effect on growth inhibition of HL-60 cells and changes in gene expression. Moreover, 100 nmol/L bryostatin 1 antagonized the cytostatic effects and adherence induced by phorbol esters. Our results thus suggest that bryostatin 1 activates HL-60 cell protein kinase C and that this effect is associated with induction of monocytic differentiation.
Expression of both the c-fos and c-sis protooncogenes during myeloid differentiation has been detected in cells of the monocytic lineage. Since an increase in c-fos transcripts was not detected during dimethylsulfoxide induced HL-60 granulocytic differentiation, it was suggested that within the myeloid series c-fos gene expression might be lineage specific. In the present study, we have determined whether expression of the c-fos and c-sis genes is indeed specific for the monocytic pathway or rather common to both the granulocyte and monocyte pathways. C-fos and c-sis gene expression was analyzed in freshly isolated human granulocytes and monocytes, in human HL-60 promyelocytic leukemia cells induced to differentiate along the granulocytic or monocytic pathway, in myeloblasts from five patients with the M1 or M2 subtype of acute myeloblastic leukemia (AML) and in blasts from six patients with M4 myelomonocytic leukemia. The level of c-fos mRNA was fifteen times higher in granulocytes as compared with monocytes. An increase in c-fos expression was also found in HL-60 cells differentiated along the granulocytic pathway after exposure to hypoxanthine, hexamethylene bisacetamide, and the combination of retinoic acid and dibutyryl adenosine 3'5' cyclic monophosphate. Three of 5 M1 and M2 leukemic myeloblast preparations depleted of lymphoid and monocytic cells and all six M4 leukemic cells expressed c-fos transcripts. In contrast, c-sis gene transcripts were detectable in monocytes and during drug induced monocytic differentiation of the HL-60 cells but not in granulocytes during granulocytic differentiation of the HL-60 cells or in AML samples. Thus, in the myeloid series, c-sis gene expression is lineage specific while expression of the c-fos gene is found in both lineages and may be related to metabolic pathways common to both granulocytes and monocytes.
Cell strains derived by culture of malignant glioma (astrocytoma grade III-IV) surgical specimens were tested for the production of DNA interstrand cross-links (ISC) and DNA-protein cross-links following treatment in vitro with 1-(2-chloroethyl)-1-nitrosourea, 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU, carmustine), 1-(2-chloroethyl)-3-(2,6-dioxo-1-piperidyl)-1-nitrosourea (PCNU), cis-dichlorodiammineplatinum(II) (cisplatin), and 3,6-diaziridinyl-2,5-bis(carboethoxyamino)-1,4-benzoquinone (diaziquone). ISC and DNA-protein crosslinks were measured by means of the DNA alkaline elution technique. Large differences among the cell strains were observed in DNA cross-linking responses to individual agents. The DNA responses to the chloroethylnitrosoureas, cisplatin, and diaziquone were largely independent of each other, except for a weak correlation between ISC responses to chloroethylnitrosoureas were distributed bimodally, in accord with a phenotypic distinction between Mer+ and Mer- cells. ISC responses to cisplatin and diaziquone showed significant variation among cell strains, but the distributions were not bimodal. The results demonstrate the existence of diverse DNA cross-linking response patterns among cell strains from different tumors of a given histological type.
Activation of the proto-oncogenes c-fos, c-fms, and c-sis has been associated with monocytic differentiation. In the present study, we monitored the relationship of c-myc, c-fos, c-fms, and c-sis expression to interferon-gamma (IFN-gamma)-induced monocytic differentiation of human HL-60 promyelocytic leukemia cells. Treatment of HL-60 cells with 500 U/ml IFN-gamma arrested cell proliferation after 3 days. Appearance of the monocytic phenotype was manifested within 24 hr of IFN-gamma exposure by: increased nitroblue tetrazolium reduction; increased cell surface expression of the HLA-DR, Mo1, and MY4 antigens; and induction of transcripts for the second component of complement (C2) and tumor necrosis factor. In contrast, c-myc expression decreased as a later event after 72 hr of IFN-gamma exposure, and c-fos transcripts remained undetectable until 5 days of treatment. Furthermore, c-fms RNA and transcripts for the macrophage marker apolipoprotein E were induced only after 7 days. Finally, expression of the c-sis proto-oncogene at the RNA and protein levels remained undetectable after induction with IFN-gamma. These findings would thus suggest that declines in c-myc RNA, as well as induction of c-fos, c-fms, and c-sis expression, are not requisite events in the commitment of HL-60 cells to IFN-gamma-induced monocytic differentiation. Expression of c-fos and c-fms, however, is associated with acquisition of markers associated with maturation to macrophages.
In human umbilical vein and bovine aortic endothelial cells in culture c-sis gene expression and secretion of platelet-derived growth factor (PDGF) has been previously demonstrated. We now report the presence of PDGF-1 and PDGF-2/sis mRNA transcripts in primary cultures of human iliac artery endothelial cells (HIA-EC). Concomitantly, these cells synthesize and secrete PDGF-like proteins identified by direct immunoprecipitation with specific PDGF antiserum. The PDGF proteins secreted by HIA-EC have molecular weights of 31 and 35 kd under nonreducing conditions. Upon reduction these proteins are converted to the monomeric 15- and 16-kd forms. Conditioned media derived from HIA-EC stimulated the incorporation of 3H-thymidine by 3T3 cells and competed with 125I-PDGF for its binding to 3T3 cell membrane receptors. The biologic activity was stable to heating at 100 degrees C for 10 min and sensitive to reducing agents, properties similar to those of authentic PDGF. Production of PDGF-like mitogen by the human arterial endothelial cells may play an important role in the paracrine modulation of arterial wall regeneration following vascular injury.