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H Joenje

Publications and source records attributed to H Joenje.

At least 73 records · Page 4Linked to original sources
PubMed1995

Fanconi anaemia research: current status and prospects.

Fanconi anaemia (FA) is an autosomal recessive disease featuring diverse clinical symptoms in addition to chromosomal instability and hypersensitivity to crosslinking agents. The much increased risk of FA patients developing leukaemia and squamous cell carcinomas makes FA an important model disease for cancer predisposition. Studies documenting the characteristics of FA cells and their response to environmental toxins have failed thus far to disclose the basic cellular process that is primarily disturbed in FA cells. Complementation analysis suggests that mutations in at least four different genes can cause FA (complementation groups FA-A to FA-D). The cDNA for FA-C has been cloned and found to encode a novel protein that localises to the cytoplasmic compartment of cells. Even though the protein's function is still unknown at present, research has now reached the point from where rapid progress to a detailed understanding of this syndrome may be foreseen.

Child↗
PubMed1995

Microcell mediated chromosome transfer maps the Fanconi anaemia group D gene to chromosome 3p.

Fanconi anaemia (FA) is an autosomal recessive disorder characterized by progressive pancytopenia, short stature, radial ray defects, skin hyperpigmentation and a predisposition to cancer. Cells from FA patients are hypersensitive to cell killing and chromosome breakage induced by DNA cross-linking agents such as mitomycin C (MMC) and diepoxybutane (DEB). Consequently, the defect in FA is thought to be in DNA crosslink repair. Additional cellular phenotypes of FA include oxygen sensitivity, poor cell growth and a G2 cell cycle delay. At least 5 complementation groups for Fanconi anaemia exist, termed A through E. One of the five FA genes, FA(C), has been identified by cDNA complementation, but no other FA genes have been mapped or cloned until now. The strategy of cDNA complementation, which was successful for identifying the FA(C) gene has not yet been successful for cloning additional FA genes. The alternative approach of linkage analysis, followed by positional cloning, is hindered in FA by genetic heterogeneity and the lack of a simple assay for determining complementation groups. In contrast to genetic linkage studies, microcell mediated chromosome transfer utilizes functional complementation to identify the disease bearing chromosome. Here we report the successful use of this technique to map the gene for the rare FA complementation group D (FA(D)).

Cell Line↗
PubMed1994

The formation of one-G deletions as a consequence of single-oxygen-induced DNA damage.

Single-stranded M13mp10 DNA containing a 144-bp mutational target sequence in the lacZ alpha gene was treated with singlet oxygen (1O2) generated by thermodissociation of the endoperoxide of 3,3'-(1,4-naphthalene-1,4-diyl)dipropionate (NDPO2). After transfection to non-SOS-induced E. coli cells, 32 mutants preselected for a mutation in the 144-bp target were collected and analyzed by DNA sequencing. One-G deletions represented the predominant type of mutation accounting for 50% of the mutations analyzed. The remaining part appeared to consist of base substitutions, i.e. G-->T transversions (34%), C-->T transitions (12.5%) and one T-->C transition (3%). Sixty percent of the mutations were found in two major mutational hotspots. We conclude that the predominant one-G deletions are due to a guanine reaction product which might be specific for 1O2.

Bacteriophage M13↗
PubMed1994

Mutagenicity of metabolic oxygen radicals in mammalian cell cultures.

Reactive oxygen species produced by normal cellular metabolism have been considered to play a causative role in spontaneously occurring genomic instability and carcinogenesis. To study the genotoxic consequences of an enhanced flux of metabolically produced reactive oxygen species, cells may be exposed to hyperoxia (elevated concentrations of oxygen), a condition known to generate high levels of microscopically visible chromosomal damage. Here we assess the mutagenic potential of normobaric hyperoxia in several mammalian cells lines (CHO-K1-BH4 and AS52 Chinese hamster cells and TK6 human lymphoblastoid cells) using different target genes, including hprt, xprt and tk. Exposure of cell cultures to hyperoxia to 10-40% clonogenic cell survival, failed to induce mutations at the hprt and xprt loci. In human TK6 cells, hyperoxia failed to induce normal growing tk mutants, but efficiently induced slow growing tk mutants. The latter type of mutant is supposed to result from very large deletions or mutlilocus events. Our results suggest that elevated levels of endogenous activated oxygen species are inefficient in inducing point mutations or small deletions, but tend to generate gross rearrangements. Mammalian cells under oxidative stress thus exhibit a hyper-recombination phenotype. The carcinogenic impact of metabolic oxygen radical fluxes may thus be based on enhanced mitotic recombination rates, leading to tumor suppressor gene inactivation through 'loss of heterozygosity'.

Animals↗
PubMed1994

The ambivalent role of glutathione in the protection of DNA against singlet oxygen.

Glutathione (GSH) was examined with respect to its ability to protect DNA against 1O2 damage. We have found that GSH protected, at least partly, the DNA against inactivation by 1O2. Up to 10 mM the protection increased as a function of GSH concentration. Above 10 mM the protection remained constant and less than expected on the basis of scavenging/quenching of 1O2, in contrast to the protection offered by sodium-azide. Especially at the higher concentrations of GSH the protection against the biological inactivation is accompanied by an increase in single-strand breaks and also probably lethal base damage. However, all together the data suggest that at least in the physiologically important range (0.1-10 mM) GSH is able to protect efficiently against 1O2-induced inactivating DNA damage.

Azides↗
PubMed1993

Association between bleomycin genotoxicity and non-constitutional risk factors for head and neck cancer.

Sensitivity of phytohaemagglutinin-stimulated lymphocytes to bleomycin clastogenicity is increased in patients with tumours in organs and tissues that are in direct contact with the external environment, such as the mucosa of the head and neck. Sensitivity to bleomycin may reflect a genetically determined hypersensitivity to certain genotoxicants and therefore may be important in the carcinogenic process. In this study the applicability of bleomycin genotoxicity was investigated in cultured lymphocytes of forty individuals without a tumour history. No correlations were observed with increasing age or the well-known head and neck cancer risk factors alcohol and tobacco consumption. Since inter-individual variation in sensitivity greatly exceeded intra-individual variation, our results suggest that an elevated bleomycin clastogenicity score may identify individuals who have a constitutional hypersensitivity towards certain genotoxicants and may show an increased cancer susceptibility.

Alcohol Drinking↗
PubMed1993

Mechanism of hyperoxia-induced chromosomal breakage in Chinese hamster cells.

Exposure of cell cultures to hyperoxia, i.e., an atmosphere containing more than 20% O2, results in various genotoxic effects. The most prominent effect of hyperoxia is its clastogenicity. In this paper, earlier published data, obtained from research devoted to the mechanism of hyperoxia-induced clastogenesis, are reviewed. In addition, new data are presented concerning the hyperoxia-sensitivity of the DNA-repair deficient Chinese hamster cell lines xrs1, irs1, and EM9. None of these ionizing radiation-sensitive mutants showed hypersensitivity to hyperoxia, as measured by chromosomal aberration induction and loss of clonogenic cell survival. From the normal hyperoxia-sensitivity of xrs1, it may be concluded that DNA double strand breaks, of the type that are induced by ionizing radiation, do not play a role in chromosomal aberration formation by hyperoxia. In addition, since xrs1 is hypersensitive to drugs that inhibit topoisomerase II, it seems rather unlikely that exposure to hyperoxia affects topoisomerase II activity. Based on circumstantial evidence we hypothesize that perturbation of poly(ADP-ribose) metabolism may play a critical role in the mechanism of hyperoxia-induced clastogenesis.

Animals↗
PubMed1993

Mutational specificity of oxidative DNA damage.

In this paper we describe our studies on the mutagenic consequences of oxidative DNA damage introduced by radiation-induced OH radicals (.OH) and by exposure to singlet oxygen (1O2), released by thermo-dissociation of the endoperoxide 3,3'-(1,4-naphthalidene) dipropionate (NDPO2). We have made use of M13mp10 bacteriophage and pUC18 plasmid DNA, containing a 144 base pair (bp) insert in the lacZ alpha gene. This 144 bp insert was used as a mutational target sequence. When dilute aqueous solutions of double-stranded (ds) M13mp10 (plus 144 bp insert) were gamma-irradiated in the presence of oxygen (O2; 100% .OH) or nitrous oxide (N2O; 90% .OH, 10% .H), very specific mutation spectra were found. Mainly bp substitutions were observed, of which C/G to G/C transversions are the predominant type. Moreover, the mutations are for the most part concentrated into two mutational hot spots: a minor and major one. Differences between the oxic (O2) and anoxic (N2O) mutation spectra could also be observed. Under N2O-1 bp deletions were detected, which are absent in the presence of O2, and in the anoxic spectrum more C/G to A/T transversions are present. To investigate whether these differences were due to the small amount of H radicals, which are formed under N2O, ds M13mp10 (plus 144 bp insert) was exposed to gamma-rays in phosphate buffer under nitrogen (55% .H, 45% .OH). Under these conditions a remarkable shift was observed from C/G-->G/C to C/G-->A/T transversions, while the mutations were far more scattered along the 144 bp sequence and no -1 bp deletions were detected. These results strongly suggest that H radicals do not cause -1 bp deletions, but may be responsible for the observed C/G to A/T transversions. The kind of bp substitution not only appeared to be dependent on the type of the water radicals, but also appeared to be strongly influenced by the replicon in which the target sequence is incorporated. When an oxygenated solution of pUC18 plasmid DNA (plus 144 bp insert) is irradiated, mainly C/G to A/T transversions were found at the same major hot spot instead of C/G to G/C transversions when the 144 bp sequence is part of M13mp10 DNA. Finally, in agreement with the observation that 1O2 reacts preferentially with guanine in DNA, a guanine is involved in most of the mutations scored after exposure of single-stranded (ss) M13mp10 DNA to NDPO2-generated 1O2.(ABSTRACT TRUNCATED AT 400 WORDS)

Base Sequence↗
PubMed1993

Singlet oxygen-induced DNA damage: product analysis, studies of biological consequences and characterization of mutations.

The DNA lesions induced by free 1O2 and the biological and mutagenic consequences of 1O2-induced DNA damage have been studied. Using anion exchange HPLC, reverse-phase HPLC with electrochemical detection and 32P-postlabelling methods, we have shown that 1O2 reacts with 2'-deoxyguanine 3'-monophosphate (dGp) but not with any other dNp. Reaction with dGp yields a large number of products; one minor product was identified as 7-hydro-8-oxo-2'-deoxyguanosine 3'-monophosphate (8-oxo-dGp), and a second tentatively as a formamidopyridine derivative of dGp. 8-Oxo-dGp was also found after reaction of 1O2 with single-stranded (ss) DNA, double-stranded (ds) DNA or an oligonucleotide (16-mer) having one G. With the oligonucleotide we found a second unidentified reaction product. With ss DNA, 8-oxo-dG was a much more prominent product than in the reaction of 1O2 with free dGp and the yield was about eight-fold higher than with ds DNA. This agrees with our finding that ss M13 DNA is at least 100-fold more sensitive than ds M13 DNA to biological inactivation by 1O2. The inactivation of ss M13 DNA must be largely due to 1O2-induced lesions other than 8-oxo-dG. In agreement with the observed preferential reaction of 1O2 with dG, most of the mutations induced by 1O2 in ss or ds M13mp10 DNA occurred at a G or G/C basepair, respectively. A preference for G(C) to T(A) transversions was observed for which 8-oxo-dG might have been responsible. In ss DNA, a significant number of mutations are characterized by the fact that a G is deleted.

Bacteriophage M13↗
PubMed1992

Cytogenetic alterations associated with P-glycoprotein- and non-P-glycoprotein-mediated multidrug resistance in SW-1573 human lung tumor cell lines.

Multidrug resistance can be induced in mammalian cells by selection with a single cytotoxic agent. Overproduction of the energy-dependent drug efflux pump P-glycoprotein, encoded by the mdr1 gene, has been identified as the cause of one form of multidrug resistance. The molecular basis of other forms of multidrug resistance is unknown. Doxorubicin selection of the human squamous lung cancer cell line SW-1573 resulted in multidrug-resistant sublines in which a non-P-glycoprotein-mediated form of multidrug resistance precedes mdr1 expression. Here we present a cytogenetic analysis of both non-P-glycoprotein-mediated multidrug-resistant and P-glycoprotein-mediated multidrug-resistant sublines derived from SW-1573. Three independently derived non-P-glycoprotein-mediated multidrug-resistant sublines showed a heterozygous deletion of the short arm of chromosome 2 (p23-pter), whereas alterations of chromosome 7 were present in the P-glycoprotein-mediated multidrug-resistant cell lines. In one series of clonally derived P-glycoprotein-mediated multidrug-resistant sublines, mdr1 overexpression was accompanied by various markers of chromosome 7 with breakpoints at 7q22, the mdr1 gene being known to be located at 7q21.1. Our data suggest that in SW-1573 cells acquisition of non-P-glycoprotein-mediated multidrug resistance is accompanied by a specific deletion or a translocation involving the short arm of chromosome 2, whereas in the emergence of P-glycoprotein-mediated multidrug resistance a rearrangement of the long arm of chromosome 7 is a critical event.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1992

Effect of iron chelators on the cytotoxic and genotoxic action of hyperoxia in Chinese hamster ovary cells.

The iron chelators o-phenanthroline and desferrioxamine were tested for their ability to protect Chinese hamster ovary cells against the cytotoxic and genotoxic effects of normobaric hyperoxia. Desferrioxamine added at sub-toxic concentrations (up to 2.5 microM) over a period of several days had no protective effect on hyperoxia-induced clonogenic cell killing and growth inhibition. The clastogenic effect of hyperoxia was strongly potentiated by desferrioxamine, while the induction of sister-chromatid exchanges (SCEs) by hyperoxia was unaffected. Similarly, o-phenanthroline (up to 0.25 microM) had no protective effect on hyperoxia-induced cell killing, growth inhibition, and SCE induction, while also this compound potentiated the clastogenic effect of hyperoxia. These results do not support a critical role for cellular iron in the mechanism of toxicity by normobaric hyperoxia in CHO cells. However, the results may still be consistent with a critical involvement of particular iron fraction(s) not susceptible to the chelators used. Furthermore, our results show that concentrations of iron chelators known to protect against short-term (up to 1 h) toxic exposure to oxidative stress become toxic themselves when applied chronically, i.e., in the order of days.

Animals↗
PubMed1992

Interaction of singlet oxygen with DNA and biological consequences.

To study the interaction of singlet oxygen (1O2) with DNA and the biological consequences of 1O2-induced DNA damage, we used the thermodissociable endoperoxide of 3,3'-(1,4 naphthalidene) dipropionate (NDPO2) as a generator of free 1O2 in reactions with (1) 2'-deoxynucleoside 3'-monophosphates (dNps), (2) an oligonucleotide (16-mer) having one deoxyguanine (dG), (3) native and denaturated rat kidney DNA and (4) single-stranded (ss) and double-stranded (ds) bacteriophage M13mp10 DNA. Using both anion exchange and reversed phase HPLC and 32P-postlabeling analyses, it was found that exposure of the various dNps to chemically generated 1O2 led to a detectable reaction with dGp and not with dAp, dCp, d5mCp or Tp. The reaction with dGp led to degradation of this nucleotide and the formation of a large number of reaction products, one of which could be identified as 7-hydro-8-oxo-2'-deoxyguanosine 3'-monophosphate (8-oxo-dGp). A second product could tentatively be identified as a formamido pyrimidine derivative of dGp (Fapy-dGp). When ss DNA, ds DNA or the oligonucleotide were exposed to 1O2, the formation of 8-oxo-dG could also be demonstrated. With the oligonucleotide, we found a so far unidentified reaction product. Under the same reaction conditions the yield of 8-oxo-dG was about 8-fold higher in ss DNA than in ds DNA. In ss DNA 8-oxo-dG seemed to be a more prominent product than in the case of reaction of 1O2 with free dGp. Reaction of 1O2 with ss or ds M13mp10 DNA led to biological inactivation of these DNAs, ss DNA being at least 100-fold more sensitive than ds DNA. It could be concluded that inactivation of the ss DNA must be largely due to 1O2-induced DNA lesions other than 8-oxo-dG. In agreement with the observed preferential reaction of 1O2 with dG most of the so far sequenced mutations, induced by 1O2 in a 144 bp mutation target sequence inserted in the lacZ alpha gene of ss or ds M13mp10 DNA, occurred at a G or G/C base pair respectively. A preference for G(C) to T(A) transversions can be observed for which 8-oxo-dG might have been responsible. In ss DNA a significant number of the mutations are characterized by the fact that a G is deleted.

Animals↗
PubMed1992

Cell culture models for oxidative stress: superoxide and hydrogen peroxide versus normobaric hyperoxia.

According to the free radical theory of aging, loss of cellular function during aging is a consequence of accumulating subcellular damage inflicted by activated oxygen species. In cells, the deleterious effects of activated oxygen species may become manifest when the balance between radical formation and destruction (removal) is disturbed creating a situation denoted as 'oxidative stress'. Cell culture systems are especially useful to study the effects of oxidative stress, in terms of both toxicity and cellular adaptive responses. A better understanding of such processes may be pertinent to fully comprehend the cellular aging process. This article reviews three model systems for oxidative stress: extracellular sources of O2-. and H2O2, and normobaric hyperoxia (elevated ambient oxygen). Methodological and practical aspects of these exposure models are discussed, as well as their prominent effects as observed in cultures of Chinese hamster cell lines. Since chronic exposure models are to be preferred, it is argued that normobaric hyperoxia is a particularly relevant oxidative stress model for in vitro cellular aging studies.

Animals↗
PubMed1991

Fragile sites and chromosome instability: the distribution of breaks induced by cis-diamine-dichloro-platinum (II) in Fanconi anemia lymphocyte cultures.

The distribution of chromosome breaks induced by the antitumor drug cis-diamine-dichloroplatinum (II) in lymphocyte cultures from Fanconi anemia patients was analyzed. Breakpoints occurred nonrandomly over an arbitrarily defined human karyotype of 319 bands. These bands were classified according to either their banding pattern or their fragile site status (whether or not a fragile site of a given type is located at a chromosomal band). A significant involvement of G-light and fragile site bands was detected. The preferential occurrence of breaks at fragile site bands was limited to common fragile site bands (essentially of the aphidicolin-type).

Cells, Cultured↗
PubMed1991

Characterization of oxygen-resistant Chinese hamster ovary cells. III. Relative resistance of succinate and alpha-ketoglutarate dehydrogenases to hyperoxic inactivation.

We have recently shown that exposure of Chinese hamster ovary (CHO) cells to a toxic dose of normobaric hyperoxia (98% O2 for 3 days) caused a disturbance of cellular energy metabolism, that is, respiratory failure followed by stimulation of glycolytic activity and a net depletion of ATP. Respiratory failure was correlated with a selective inactivation of three mitochondrial enzymes, that is, partial inactivation of NADH dehydrogenase and virtually complete inactivation of succinate and alpha-ketoglutarate dehydrogenase activities (Schoonen et al., 1990). To elucidate the biochemical basis of resistance to hyperoxia in a previously described oxygen-resistant substrain of Chinese hamster ovary (CHO) cells, we compared the resistant cells with wildtype CHO cells with respect to several key parameters of oxidative and glycolytic energy metabolism. The two cell types were critically different in that the succinate and alpha-ketoglutarate dehydrogenases of the oxygen-resistant cells were relatively resistant to inactivation by hyperoxia, which may at least partly explain their enhanced capacity to respire and survive under hyperoxic conditions. Although the biochemical basis for the observed enzyme resistance to hyperoxic inactivation remains to be elucidated, the present data underscore the importance of succinate and alpha-ketoglutarate dehydrogenases as critical targets in hyperoxic killing of wildtype CHO cells.

Adenosine Triphosphate↗
PubMed1991

Effect of antioxidants on hyperoxia-induced chromosomal breakage in Chinese hamster ovary cells: protection by carnosine.

We have studied the effect of various compounds, known as antioxidants, on the level of hyperoxia (80-90% O2)-induced chromosomal aberrations in Chinese hamster ovary cells: ascorbic acid, alpha-tocopherol, carnosine, imidazole-4-acetic acid, glutathione monoethylester, N-acetylcysteine and ethoxyquin. Carnosine (beta-alanyl-histidine) appeared to be the only compound that reduced chromosomal breakage. The effect was also present in cultures post-treated with caffeine (at 2.5 mM, 3 h before harvest), indicating that the apparent protection was not due to selective arrest of chromosomally damaged cells in the G2 phase of the cell cycle. Imidazole-4-acetic acid, a compound structurally very similar to carnosine, had no detectable effect. Ascorbic acid, N-acetylcysteine, glutathione monoethylester and ethoxyquin were found to have a pro-oxidant effect, i.e. they apparently potentiated the clastogenic effect of hyperoxia. Carnosine is the first compound shown to protect against the clastogenicity of normobaric hyperoxia and may thus be a useful tool in elucidating the underlying mechanism.

Acetylcysteine↗