Biomedical subjects

C Bailly

Publications and source records attributed to C Bailly.

At least 181 records · Page 10Linked to original sources

PubMed1996

Effect of human basic fibroblast growth factor on fibroblast proliferation, cell volume, collagen lattice contraction: in comparison with acidic type.

Human recombinant basic fibroblast growth factor (bFGF) is a potent mitogen for normal human dermal fibroblasts in the presence of heparin which binds to and stabilizes it. The optimal mitotic response is obtained with a concentration of 1 ng/ml of bFGF in monolayer cultures (non-differentiated fibroblasts) as well as in the better-differentiated fibroblasts obtained through the 'collagen lattices' culture system (fibroblasts embedded in a 3-dimensional collagen gel) achieving a doubling of the cell number in 8 days. Despite increasing the number of cells, bFGF decreases the ability of fibroblasts to contract collagen fibers. This inhibition is concentration-dependent and reaches a plateau at a dose of about 1 ng/ml. This effect is associated with a bFGF-induced decrease of fibroblast volume. Various dosing regimens indicate that although the highest response was obtained by daily dosing nearly optimal response was obtained either by early daily dosing or short intermittent treatment. Interestingly, the fibroblast mitotic response to bFGF decreases steadily when fibroblasts mature in collagen gels. The mitogenic properties of bFGF associated to its ability to inhibit fibroblasts contraction, if demonstrated in vivo, may be of interest in the management of wound healing.

Cell Division↗

PubMed1996

Salen-anthraquinone conjugates. Synthesis, DNA-binding and cleaving properties, effects on topoisomerases and cytotoxicity.

A series of amidoethylamino-anthraquinone derivatives bearing either one or two salen (bis(salicylidene)ethylenediamine) moieties complexed with CuII or NiII have been synthesized, and their DNA-binding and cleaving properties examined. The effects of the mono- and di-substituted anthracenedione-salen conjugates on DNA cleavage mediated by topoisomerases I and II have also been determined, as well as their cytotoxicity toward human KB cells. The anthraquinone-salen. NiII conjugates bind to GC-rich sequences in DNA, but do not cleave the macromolecule. By contrast, the anthraquinone-salen. CuII hybrids do not recognize particular nucleotide sequences but efficiently induce single-strand breaks in DNA after activation. The 5,8-dihydroxy-anthraquinone conjugates are more cytotoxic and more potent toward topoisomerase II than the non-hydroxylated analogues, but they are less cytotoxic than the salen-free anthraquinones. The attachment of a salen. CuII complex to the anthraquinone chromophore can confer DNA cleaving properties in vitro, but this is at the expense of cytotoxic activity. Anthraquinone-salen. CuII complexes may find useful employ as footprinting probes for investigating ligand-DNA interactions.

Anthraquinones↗

PubMed1996

Thin melanomas with unusual aggressive behavior: a report on nine cases. Melanoma Group of French Federation of Cancer Centers.

BACKGROUND: The major factor influencing the prognosis of cutaneous malignant melanoma (MMs) is the maximum thickness of the tumor as measured by Breslow's method. However, it has been reported that thin melanomas, which should have an excellent prognosis, may have the potential to metastasize, some with an unusually rapid course. OBJECTIVE: Our purpose was to examine prognostic indicators in relation to unusually rapid aggressive behavior in patients with thin MMs (<0.76mm). METHODS: We describe nine cases of thin MM (<.76mm) that exhibited a recurrence or metastasis during a follow-up period ranging from 3 to 10 years, among computerized records of 1118 MMs treated in a multicenter epidemiologic study. The data obtained from these nine cases were compared with nonrecurring thin MM (149 cases) of the same cohort. RESULTS: The particular aggressiveness of these thin melanomas was reflected by the short disease-free interval (3 years or less) in all ine patients. The recurring thin MM more frequently involved head and neck sites, occurred in male patients, and showed Clark's level III and IV. CONCLUSION: Our review suggests that the head and neck area is particularly involved by unusually rapidly recurring thin MM. Possible explanations are the specific problems of surgical management and the greater sun exposure of this location.

Adult↗

PubMed1996

Nodal nevi and cutaneous melanomas.

Nevocytes in melanoma-draining lymph nodes can be mistaken for melanoma metastases and may possibly transform to melanoma. During the development of a new technique for managing high-risk primary melanomas, selective lymph node dissection, we examined 4,821 nodes from 208 melanoma patients by light microscopy and immunohistochemistry. Nodal nevi were identified in 49 of 226 lymphadenectomy specimens (22%), a frequency considerably higher than previously recorded (5-6%). Nevi occurred in 57 of 4,821 nodes (1.2%), in 84% of patients in one node, in 13% of patients in two nodes, and in 3% of patients in three nodes. Nevocytes were detected in hematoxylin and eosin-stained sections in 38 of 49 cases (78%) and exclusively by immunocytochemistry with an antibody to S-100 protein in 11 of 49 (22%). Nevi were in the peripheral capsule in 93% of cases and in internal trabecula in the remaining 7%. Nevocytes surrounded a small vessel in 33% of cases. Nevi were more frequent in axillary (37 of 140, 26%) and cervical nodes (seven of 40, 18%) than in inguinal nodes (five of 46, 11%). Nevi were more frequent in sentinel nodes, the first nodes on the lymphatics draining a primary melanoma (11 of 284, 3.9%), than in nonsentinel nodes (46 of 4,537, 1.01%; p < 0.0008). One of 1,071 nodes from 50 patients with breast cancer (0.1%) and none of 521 nodes from 50 patients with pelvic cancer contained nevocytes. That nodal nevi are selectively present in melanoma patients raises the possibility of their origin from nodal melanocytes influenced by tumor products. Alternatively, the association may indicate that the nevocytes of cutaneous nevi can be disrupted and displaced by the growth of an adjacent melanoma.

Female↗

PubMed1996

Sequence-specific binding of antitumour bisquaternary ammonium heterocycles to DNA and inhibition of polymerase activity in vitro.

Ten bisquaternary ammonium heterocycles (BQA) active against experimental tumours were investigated for possible sequence-selective binding to DNA. Footprinting analyses indicated that several bound preferentially to dAdT runs consisting of at least four base pairs. Shortening of one or two spacer groups between the aromatic rings of the ligands (by replacement of CONH with NH) emerged as a prerequisite for sequence-specific binding. Other relevant factors concerned the overall shape of the ligands and the relative position of their positive charges. Footprinting plots evaluated for the BQA compound SN 6132 on the 167mer EcoRI-RsaI restriction fragment from plasmid pBR322 yielded the highest individual binding constant for the symmetrical base sequence AATTTAA, with approximate K(A) = 2.0 x 10(6)/M. Polymerase-catalysed syntheses of DNA and RNA in vitro were inhibited by all BQA derivatives, but the inhibition was much more pronounced with the sequence-specific binders SN 6999 and SN 6132 than with the non-specific ligand SN 6113.

Antineoplastic Agents↗

PubMed1996

The 1'-substituent on the anilino ring of the antitumor drug amsacrine is a critical element for topoisomerase II inhibition and cytotoxicity.

The mechanism of action of the antitumor drug amsacrine involves intercalation of the acridine chromophore into DNA and inhibition of topoisomerase II. The substituent at position 1' on the aniline is believed to be essential to the formation of the topoisomerase II/DNA cleavable complex and therefore to the cytotoxicity of the drug. To further delineate the role of the 1'-substituent, we investigated the effects on topoisomerase II activities of three anilinoacridine derivatives that differ only by the nature of the substituent at position 1'. The results of the cytotoxicity assays performed with cells sensitive (DC-3F) and resistant [DC-3F/9-hydroxy-ellipticine (9-OH-E)] to topoisomerase inhibitors are correlated with the effects of the drugs on topoisomerase II-mediated DNA cleavage in vitro. The influence of topoisomerase II alpha on the mechanism of action of the drugs was examined using resistant DC-3F/9-OH-E cells transfected with a plasmid carrying a wild-type human topoisomerase II alpha cDNA. Depending on the nature of the 1'-substituent of the drugs, the restoration of normal topoisomerase II alpha catalytic activity in human topoisomerase II alpha cDNA-transfected DC-3F/9-OH-E cells either does not modify the susceptibility of the cells to the drug or partially reverses the resistance phenotype. The molecular and cellular studies reveal that topoisomerase II alpha is implicated in the cytotoxicity of amsacrine and confirm that the substituent at position 1' on the anilino ring of amsacrine governs the interaction with topoisomerase II.

Amsacrine↗

PubMed1996

[Diabetic mastopathy with epithelioid fibroblasts :differential diagnosis from an infiltrating lobular carcinoma of the breast. Report of two cases].

Two cases of diabetic mastopathy are reported. The patients presented with a rapidly increasing mammary mass. The pathologic findings of diabetic mastopathy usually consist of a lymphocytic lobulitis, a dense stromal fibrosis and prominent epithelioid fibroblasts. In our two cases, the latter findings were initially misinterpreted as malignant cells of an invasive lobular carcinoma. These lesions were first described in longstanding insulin dependent diabetics but recent reports showed that they could also occur in patients with other auto-immune disorders (systemic lupus erythematous, hypothyroidism). Diabetic mastopathy may reoccur locally and the treatment remains to be determined.

Adult↗

PubMed1996

Interaction of DNA-threading peptide-amsacrine conjugates with DNA and chromatin.

The SPKK peptide motif which functions as a DNA minor groove binding unit in various chromosomal and gene regulatory proteins has been attached to the antitumour drug amsacrine in order to reinforce interaction with DNA. Two bifunctional molecules in which an amsacrine-4-carboxamide derivative is linked to one or two SPKK motifs via a diaminopropyl tether have been designed and synthesized. We have applied various spectroscopic methods (absorption, circular and linear dichroism) to delineate the role of the peptide moiety as opposed to the chromophoric acridine moiety in the interaction of the conjugates with both DNA and chromatin. The structural and kinetic data concur that the two peptide conjugates thread through the DNA double helix so as to intercalate their acridine chromophore, leaving the SPKK motif and the methanesulphonanilino group positioned within the minor and major grooves of the double helix respectively. The threading-type intercalation process, evidenced by stopped-flow measurements, is not affected when the DNA is wrapped around histones. Linkage of the SPKK peptide motif to intercalating drugs represents an efficient system to stabilize drug-DNA complexes.

Amsacrine↗

PubMed1996

DNA minor groove cleaving agents: synthesis, binding and strand cleaving properties of anthraquinone-oligopyrrolecarboxamide hybrids.

Three 9,10-anthraquinone-oligopyrrolecarboxamide hybrids have been prepared as potential DNA minor groove cleaving agents. Each conjugate was designed to contain a bis- or tris-pyrrolecarboxamide moiety related to netropsin or distamycin covalently linked to a 2-substituted anthraquinone chromophore capable of triggering photocleavage of DNA. AQ(NC)-Dist, having three pyrrole rings, is related to distamycin. AQ(NC)-Net and AQ(CN)-Net are related to netropsin; they differ only by the orientation of the amide bond between the anthraquinone and the netropsin moiety. The binding properties of these compounds to various natural DNAs have been studied by footprinting and circular dichroism. The introduction of the chromophore does not abolish the capacity of the drugs to recognize AT-rich sequences in DNA selectively. There is apparently little correlation between this property and the ability to trigger photo-induced DNA cleavage. AQ(CN)-Net is almost totally inactive in the cleavage assays whereas it manifestly binds selectively to AT-rich tracts. With AQ(NC)-Net and AQ(NC)-Dist, complete conversion of form I to form II of circular DNA is obtained. Moreover, in most cases the cleavage of DNA proved to be non-specific.

Amides↗

PubMed1996

Molecular origins of selectivity in the interaction of amsacrine-4-carboxamide with GC-rich sequences in DNA.

To determine the molecular origins of the preferential binding of an antitumour amsacrine-4-carboxamide derivative to GC-rich sequences in DNA, we have used the polymerase chain reaction to synthesize a series of oligodeoxynucleotides in which the position of the purine 2-amino group is varied and then investigated the binding of the drug to normal and modified DNA molecules by means of DNase I footprinting. The results indicate that the 2-amino group of guanine represents an important but not unique element which directs selective binding of amsacrine-4-carboxamides to GC-rich sequences.

Amsacrine↗

PubMed1995

Effects of base substitutions on the binding of a DNA-bending protein.

In order to investigate whether the 2-amino group of guanine, which lies in the minor groove of the B-form helix, can directly influence DNA flexibility and major groove recognition by proteins we have examined the properties of DNA molecules containing inosine and/or 2,6-diaminopurine (DAP) residues. Appropriately substituted tyrT(A93) DNA fragments were prepared by the polymerase chain reaction. Their mobility in non-denaturing gels was affected, consistent with changed anisotropic flexibility leading to increased curvature due to G-->I substitution and decreased curvature due to replacement of adenine with DAP. Band-shift assays of FIS protein binding revealed facilitated interaction with inosine-containing DNA and markedly reduced binding to DAP-containing DNA, attributable to altered bendability. DNase footprinting experiments confirmed that fewer sites would bind FIS in DAP-containing DNA at a given protein concentration, whereas higher levels of binding occurred with inosine-containing molecules. Thus base substitutions which affect the placement and presence of the purine 2-amino group in the minor groove can affect both the intrinsic curvature and the bendability of DNA.

2-Aminopurine↗

PubMed1995

Analogue versus digital recognition of DNA by bleomycin: an effect of the carbohydrate moiety.

We have sought to determine the influence of the carbohydrate moiety of the antitumour antibiotic bleomycin on the sequence-specific cleavage of DNA. Both bleomycin A2 and deglycobleomycin A2 produce different cleavage patterns with DNA in which the 2-amino group has been removed from guanine, added to adenine, or both, as well as on a designed DNA fragment containing a few defined cleavage sites. Although each drug cleaves DNA primarily at GpT and GpC sites, the cleavage at these sites is frequently found to be stronger with deglycobleomycin compared with bleomycin A2. Conversely, in most cases the cleavage at secondary sites, in particular at ApT steps, is significantly reduced or even abolished with deglycobleomycin. The results indicate that the gulose-mannose moiety of bleomycin A2 plays a significant role in the recognition of preferred nucleotide sequences and confirm the view that both secondary structure and interaction with guanine are involved in determining sequence-specific cleavage of DNA by bleomycin.

Antibiotics, Antineoplastic↗

PubMed1995

Localized chemical reactivity in double-stranded DNA associated with the intercalative binding of benzo[e]pyridoindole and benzo[g]pyridoindole triple-helix-stabilizing ligands.

Footprinting with methidiumpropyl-EDTA.FeII has been used to map the binding sites on duplex DNA of two closely related benzopyridoindole derivatives which selectively stabilize triple-helical DNA-oligonucleotide complexes. Both ligands bind to many sites, including certain oligopurine.oligopyrimidine tracts, with a weak preference for some (but not all) sequences rich in A.T base pairs. This indifference to primary sequence, with evidence of binding to the commonly disfavoured (A)n.(T)ntracts, may at least partially explain why the ligands stabilize triplex structures composed of T.A.T pairings. Neither 3-methoxy-7H-8-methyl-11- [(3'amino)propylamino]benzo[e]pyrido[4, 3-b]indole (BePI) nor 3- methoxy-7-[3'-diethylamino)propylamino]-10-methyl-11H- benzo[g]pyrido[4,3-b]indole (BgPI) affect the reaction of dimethyl sulphate or potassium tetrachloropalladinate with the N7 of purines in the major groove, but both enhance the reactivity of purines (mostly adenine residues) towards diethylpyrocarbonate, both proximal and distal to their identified binding sites. With potassium permanganate and osmium tetroxide/pyridine, probes for the accessibility of the 5,6 double bond of pyrimidine residues, BgPI has a more potent effect than BePI and, generally, the reaction with KMnO4 is more pronounced than that with OsO4. BgPI conspicuously potentiates the oxidation of pyrimidines in the triplet sequences 3'-ATA, 3'-GTA and 3'-GCA, whereas BePI enhances the reactivity of OsO4 towards thymine in sequences 3'-ATYR, with no effect on cytosine residues. Thus, despite their structural homology and common lack of specific sequence preferences, the two benzopyridoindole derivatives induce distinct conformational changes in duplex DNA, not just within the sites where footprints can be detected.

Animals↗

PubMed1995

Effects of two distamycin-ellipticine hybrid molecules on topoisomerase I and II mediated DNA cleavage: relation to cytotoxicity.

Two distamycin-ellipticine conjugates were examined for their ability to modulate topoisomerase I and topoisomerase II-DNA cleavable complex formation in vitro. Hybrid molecules Distel (1+) and Distel (2+) both contain a DNA-intercalating chromophore and a tris-pyrrole element capable of binding within the minor groove of DNA. The two drugs differ only in the nature of the side chain attached to the distamycin moiety. The monocationic hybrid Distel (1+) is a dual topoisomerase I and II inhibitor with characteristics differing from those of the parent compounds distamycin and ellipticine. By contrast, the biscationic hybrid Distel (2+) exerts no significant effects on either topoisomerase I or II. The cytotoxic properties of the two drugs towards P388 leukaemic cells sensitive and resistant to camptothecin correlate with topoisomerase inhibitory properties but not with DNA-binding properties.

Animals↗

PubMed1995

The influence of the 2-amino group of guanine on DNA conformation. Uranyl and DNase I probing of inosine/diaminopurine substituted DNA.

The conformation of the DNA helix is supposed to be a critical element in site-specific recognition by ligands both large and small. Groove width is one important measure of the conformation which varies with the local nucleotide composition, perhaps because of the presence of a purine 2-amino group on G.C base pairs. We have probed DNA with G-->inosine (I) and/or A-->diaminopurine (DAP) substitutions to see whether the location of the purine 2-amino group can indeed affect the minor groove width. At acid pH, the reactivity towards uranyl nitrate is modulated in substituted DNA quite differently from natural DNA, consistent with a marked narrowing of the minor groove at sites of G-->I substitution and widening at sites of A-->DAP replacement. The latter exerts the dominant effect. The expected changes in conformation are equally evident in the patterns of susceptibility to DNase I cleavage, but not to hydroxyl radical attack. Nuclease cleavage is maximal in normal and substituted DNA at regions of inferred moderate groove width which are generally little affected by the nucleotide substitutions. Consistent with models of sequence-dependent cutting by DNase I we find that the presence of a purine 2-amino group on the base pair three places upstream of the cutting site has a profound influence on the rate of reaction.

Base Sequence↗

PubMed1995

Transferring the purine 2-amino group from guanines to adenines in DNA changes the sequence-specific binding of antibiotics.

The proposition that the 2-amino group of guanine plays a critical role in determining how antibiotics recognise their binding sites in DNA has been tested by relocating it, using tyrT DNA derivative molecules substituted with inosine plus 2,6-diaminopurine (DAP). Irrespective of their mode of interaction with DNA, such GC-specific antibiotics as actinomycin, echinomycin, mithramycin and chromomycin find new binding sites associated with DAP-containing sequences and are excluded from former canonical sites containing I.C base pairs. The converse is found to be the case for a group of normally AT-selective ligands which bind in the minor groove of the helix, such as netropsin: their preferred sites become shifted to IC-rich clusters. Thus the binding sites of all these antibiotics strictly follow the placement of the purine 2-amino group, which accordingly must serve as both a positive and negative effector. The footprinting profile of the 'threading' intercalator nogalamycin is potentiated in DAP plus inosine-substituted DNA but otherwise remains much the same as seen with natural DNA. The interaction of echinomycin with sites containing the TpDAP step in doubly substituted DNA appears much stronger than its interaction with CpG-containing sites in natural DNA.

2-Aminopurine↗

PubMed1995

Comparison of different footprinting methodologies for detecting binding sites for a small ligand on DNA.

In order to assess the utility of different methods of footprinting applied to the study of sequence-selective small molecule-DNA interaction we have performed a homologous series of experiments on the binding of echinomycin, a bis-intercalator, to a 133 base pair DNA restriction fragment containing a small number of discrete binding sites. Two of those sites each contained a pair of closely clustered CpG steps, the cognate dinucleotide sequence which is the common denominator of sites recognised by echinomycin. DNAse I was found to be much the best enzyme for footprinting in terms of sensitivity, accuracy, and ease of handling. DNAase II and micrococcal nuclease were of limited value. Excellent results were recorded with methidiumpropyl-EDTA.FeII which picked up strong binding sites and yielded sharp footprints from which a parsimonious estimate of site size could be determined. Orthophenanthroline.CuI proved to be a very suitable, sensitive chemical nuclease but hydroxyl radical footprinting with EDTA.FeII was only partially successful. Positive footprinting with conformation-sensitive probes diethylpyrocarbonate, osmium tetroxide and potassium permanganate yielded information to complement that afforded by the enzymic and chemical nucleases. Evidence of binding to both CpG steps in the clustered pair was obtained, with indications of possible cooperativity.

Base Sequence↗

PubMed1995

Use of electric linear dichroism and competition experiments with intercalating drugs to investigate the mode of binding of Hoechst 33258, berenil and DAPI to GC sequences.

The drugs Hoechst 33258, berenil and DAPI bind preferentially to the minor groove of AT sequences in DNA. Despite a strong selectivity for AT sites, they can interact with GC sequences by a mechanism which remains so far controversial. The 2-amino group of guanosine represents a steric hindrance to the entry of the drugs in the minor groove of GC sequences. Intercalation and major groove binding to GC sites of GC-rich DNA and polynucleotides have been proposed for these drugs. To investigate further the mode of binding of Hoechst 33258, berenil and DAPI to GC sequences, we studied by electric linear dichroism the mutual interference in the DNA binding reaction between these compounds and a classical intercalator, proflavine, or a DNA-threading intercalating drug, the amsacrine-4-carboxamide derivative SN16713. The results of the competition experiments show that the two acridine intercalators markedly affect the binding of Hoechst 33258, berenil and DAPI to GC polynucleotides but not to DNA containing AT/GC mixed sequences such as calf thymus DNA. Proflavine and SN16713 exert dissimilar effects on the binding of Hoechst 33258, berenil and DAPI to GC sites. The structural changes in DNA induced upon intercalation of the acridine drugs into GC sites are not identically perceived by the test compounds. The electric linear dichroism data support the hypothesis that Hoechst 33258, berenil and DAPI interact with GC sites via a non-classical intercalation process.

Base Sequence↗