mailliet patrick | Muséum National d'Histoire Naturelle (original) (raw)
Papers by mailliet patrick
Biochemistry, 2003
The telomeric G-rich single-stranded DNA can adopt in vitro an intramolecular quadruplex structur... more The telomeric G-rich single-stranded DNA can adopt in vitro an intramolecular quadruplex structure, which has been shown to directly inhibit telomerase activity. The reactivation of this enzyme in immortalized and most cancer cells suggests that telomerase is a relevant target in oncology, and telomerase inhibitors have been proposed as new potential anticancer agents. In this paper, we have analyzed the selectivity of four ethidium derivatives and ethidium itself toward different G-quadruplex species, with electrospray mass spectrometry and competitive equilibrium dialysis and evaluated their inhibitory properties against telomerase. A selectivity profile may be obtained through electrospray ionization mass spectrometry (ESI-MS), which is in fair agreement with competitive equilibrium dialysis data. It also provides unambiguous data on the number of binding sites per nucleic acid (maximal number of two ethidium derivatives per quadruplex, in agreement with external stacking). Our e...
Farnesyltransferase Inhibitors in Cancer Therapy, 2000
Nucleic Acids Research, 2013
The triazine derivative 12459 is a potent G-quadruplex ligand that triggers apoptosis or delayed ... more The triazine derivative 12459 is a potent G-quadruplex ligand that triggers apoptosis or delayed growth arrest, telomere shortening and G-overhang degradation, as a function of its concentration and time exposure to the cells. We have investigated here the DNA damage response induced by 12459 in A549 cells. Submicromolar concentrations of 12459 triggers a delayed Chk1-ATR-mediated DNA damage response associated with a telomeric dysfunction and a G2/M arrest. Surprisingly, increasing concentrations of 12459 leading to cell apoptosis induced a mechanism that bypasses the DNA damage signaling and leads to the dephosphorylation of Chk1 and c-H2AX. We identified the phosphatase Protein Phosphatase Magnesium dependent 1D/Wild-type P53-Induced Phosphatase (PPM1D/WIP1) as a factor responsible for this dephosphorylation. SiRNA-mediated depletion of PPM1D/WIP1 reactivates the DNA damage signaling by 12459. In addition, PPM1D/WIP1 is activated by reactive oxygen species (ROS) induced by 12459. ROS generated by 12459 are sufficient to trigger an early DNA damage in A549 cells when PPM1D/WIP1 is depleted. However, ROS inactivation by N-acetyl cysteine (NAC) treatment does not change the apoptotic response induced by 12459. Because PPM1D expression was recently reported to modulate the recruitment of DNA repair molecules, our data would suggest a cycle of futile protection against 12459, thus leading to a delayed mechanism of cell death.
Cellular and Molecular Life Sciences, 2012
Functional telomeres are protected from nonhomologous end-joining (NHEJ) and homologous recombina... more Functional telomeres are protected from nonhomologous end-joining (NHEJ) and homologous recombination (HR) DNA repair pathways. Replication is a critical period for telomeres because of the requirement for reconstitution of functional protected telomere conformations, a process that involves DNA repair proteins. Using knockdown of DNA-PKcs and Rad51 expression in three different cell lines, we demonstrate the respective involvement of NHEJ and HR in the formation of telomere aberrations induced by the G-quadruplex ligand 360A during or after replication. HR contributed to specific chromatid-type aberrations (telomere losses and doublets) affecting the lagging strand telomeres, whereas DNA-PKcs-dependent NHEJ was responsible for sister telomere fusions as a direct consequence of G-quadruplex formation and/or stabilization induced by 360A on parental telomere G strands. NHEJ and HR activation at telomeres altered mitotic progression in treated cells. In particular, NHEJmediated sister telomere fusions were associated with altered metaphase-anaphase transition and anaphase bridges and resulted in cell death during mitosis or early G1. Collectively, these data elucidate specific molecular and cellular mechanisms triggered by telomere targeting by the G-quadruplex ligand 360A, leading to cancer cell death. Keywords Rad51 Á DNA-PKcs Á G-quadruplex Á Telomere Á Mitosis Abbreviations NHEJ Non-homologous end-joining HR Homologous recombination DMSO Dimethyl sulfoxide Telo-FISH Telomere-fluorescent in situ hybridization CO-FISH Chromosome orientation-FISH Electronic supplementary material The online version of this article (
Tetrahedron letters, 2004
Isoxazole derivatives Isoxazole derivatives R 0240 1,3-Dipolar Cycloaddition Route to Novel Isoxa... more Isoxazole derivatives Isoxazole derivatives R 0240 1,3-Dipolar Cycloaddition Route to Novel Isoxazole-Type Derivatives Related to Combretastatin A-4.-1,3-Dipolar cycloaddition of various 3,4,5-trimethoxyphenyl units with the nitrile oxide in situ generated from aryloxime (II) gives isoxazole-type heterocycles related to the potent anticancer drug combretastin.
European Journal of Medicinal Chemistry
Anti-cancer drug design
In order to obtain non-degradable and more potent protein-tyrosine kinase inhibitors, derived fro... more In order to obtain non-degradable and more potent protein-tyrosine kinase inhibitors, derived from the 5-(2,5-dihydroxybenzyl)-aminosalicylates already described, we have developed a new series of 5-(2,5-dihydroxybenzyl)phenylamines. The compounds, diversely substituted on the phenyl ring by alcohol, nitrile, ether, ketone, amide and thioamide groups, were tested for their ability to inhibit epidermal growth factor (EGF) receptor-associated tyrosine kinase activity in vitro. They inhibit the phosphorylation of the peptide substrate RR-Src by the EGF receptor purified from ER 22 cells, with IC50 values in the range 0.02-0.45 microns. Several of these compounds inhibit EGF-dependent DNA synthesis in ER 22 cells with IC50 values of around 1 micron and furthermore their inhibition has been found to be specific for various protein kinases.
Anti-cancer drug design
A series of platinum dichloroethylenediamine complexes [PtCl2(R-en)] bearing a side chain on one ... more A series of platinum dichloroethylenediamine complexes [PtCl2(R-en)] bearing a side chain on one carbon atom of the ethylenediamine ligand, with or without a functional group on the side chain, have been prepared and investigated for antitumor activity against L1210 leukemia. They were tested both in vitro, with cisplatin-sensitive and resistant cell lines, and in vivo, with cisplatin-sensitive and resistant tumors grafted i.p. in B6D2F1 mice. The rationale for this study was to test how charge, polarity and shape of the R side chain influence antitumor activity. Complexes carrying one or more ammonium groups on the side chain were all inactive. Derivatives with a carbamate function attached by the nitrogen atom, via a methylene group, to the ethylenediamine moiety ('N-bound' carbamate) were highly active in vitro and in vivo. The best results were obtained with these carbamates bearing hydrophobic substituents of intermediate size. Replacement of N-bound by O-bound carbamat...
Inhibiteurs de telomerase et conséquences pour la thérapeutique anti-cancéreuse
Proceedings of the National Academy of Sciences, 2002
Nucleic Acids Research, 2004
Ligand 12459, a potent G-quadruplex-interacting agent that belongs to the triazine series, was pr... more Ligand 12459, a potent G-quadruplex-interacting agent that belongs to the triazine series, was previously shown to downregulate telomerase activity in the human A549 lung carcinoma cell line. We show here that the downregulation of telomerase activity is caused by an alteration of the hTERT splicing pattern induced by 12459, i.e. an almost complete disappearance of the active (+a,+b) transcript and an over-expression of the inactive ±b transcript. Spliced intron 6 forming the ±b hTERT transcript contained several tracks of G-rich sequences able to form G-quadruplexes. By using a speci®c PCR-stop assay, we show that 12459 is able to stabilize the formation of these G-quadruplex structures. A549 cell line clones selected for resistance to 12459 have been analyzed for their hTERT splicing pattern. Resistant clones are able to maintain the active hTERT transcript under 12459 treatment, suggesting the appearance of mechanisms able to bypass the 12459-induced splicing alterations. In contrast to 12459, telomestatin and BRACO19, two other G-quadruplex-interacting agents, have no effect on the hTERT splicing pattern in A549 cells, are cytotoxic against the A549resistant clones and display a lower ef®ciency to stabilize hTERT G-quadruplexes. These results lead us to propose that 12459 impairs the splicing machinery of hTERT through stabilization of quadruplexes located in the hTERT intron 6. Differences of selectivity between 12459, BRACO19 and telomestatin for these hTERT quadruplexes may be important to explain their respective activity and inactivity against hTERT splicing.
The Journal of Organic Chemistry, 2001
Nucleic acids symposium series (2004), 2008
The binding properties of a series of known G-quadruplex ligands have been studied by ESI-MS expe... more The binding properties of a series of known G-quadruplex ligands have been studied by ESI-MS experiments. The tetramolecular (TG(4)T)(4) quadruplex and its analogues I and II blocked, respectively, at the 3' or 5'-end by a tetra-end-linker (TEL) unit were chosen as the ligands targets. The stoichiometries of the obtained complexes as well as the ligand affinity and selectivity to the different quadruplexes were determined to deduce the ligand binding site. The TEL derivatives I and II allowed the probing of the grooves contribution to the binding of ligands to G-quadruplexes, demonstrating that the 3' and 5' quartets are not equivalent binding sites for ligand end-stacking.
Nucleic Acids Research, Jul 21, 2005
The G-overhangs of telomeres are thought to adopt particular conformations, such as T-loops or G-... more The G-overhangs of telomeres are thought to adopt particular conformations, such as T-loops or G-quadruplexes. It has been suggested that G-quadruplex structures could be stabilized by specific ligands in a new approach to cancer treatment consisting in inhibition of telomerase, an enzyme involved in telomere maintenance and cell immortality. Although the formation of G-quadruplexes was demonstrated in vitro many years ago, it has not been definitively demonstrated in living human cells. We therefore investigated the chromosomal binding of a tritiated G-quadruplex ligand, 3 H-360A (2,6-N,N 0-methyl-quinolinio-3-yl)-pyridine dicarboxamide [methyl-3 H]. We verified the in vitro selectivity of 3 H-360A for G-quadruplex structures by equilibrium dialysis. We then showed by binding experiments with human genomic DNA that 3 H-360A has a very potent selectivity toward G-quadruplex structures of the telomeric 3 0-overhang. Finally, we performed autoradiography of metaphase spreads from cells cultured with 3 H-360A. We found that 3 H-360A was preferentially bound to chromosome terminal regions of both human normal (peripheral blood lymphocytes) and tumor cells (T98G and CEM1301). In conclusion, our results provide evidence that a specific G-quadruplex ligand interacts with the terminal ends of human chromosomes. They support the hypothesis that G-quadruplex ligands induce and/or stabilize G-quadruplex structures at telomeres of human cells.
Biochemical and Biophysical Research Communications, 2004
A parallel G-quadruplex structure was recently identified in the NHE III 1 element of the c-myc g... more A parallel G-quadruplex structure was recently identified in the NHE III 1 element of the c-myc gene promoter that functioned as a transcriptional repressor. Different series of telomeric G-quadruplex interacting ligands reported to block telomerase activity were evaluated in a new PCR stop assay on the c-myc quadruplex (Pu22myc). Results indicated that the cationic porphyrin TMPyP4 previously described to stabilize c-myc quadruplex and to cause transcription inhibition efficiently inhibited the assay but with a narrow selectivity when parallel experiments were performed with an oligonucleotide (Pu22mu) containing mutations in the guanine repeat which is unable to form a quadruplex. Other ligands presented potent inhibitory properties with IC 50 in the submicromolar range. 307A, a new 2,6-pyridin-dicarboxamide derivative was found to present the highest selectivity as compared to Pu22mu oligonucleotide (>90-fold). Comparison with telomeric G-quadruplex using TRAP-G4 and PCR stop assays also indicated that ligands 307A, telomestatin, and TMPyP4 are equipotent against both c-myc and telomeric sequences while other ligands displayed some partial selectivity (2-to 6-fold) towards one of these sequences. This work provides evidence that G-quadruplex ligands reported as telomerase inhibitors efficiently stabilized c-myc promoter intramolecular quadruplex and may also potentially be used to inhibit c-myc gene transcription in tumor cells.
Journal of Medicinal Chemistry, 2000
We have investigated the combined use of partial least squares (PLS) and statistical design princ... more We have investigated the combined use of partial least squares (PLS) and statistical design principles in principal property space (PP-space), derived from principal component analysis (PCA), to analyze farnesyltransferase inhibitors in order to identify "activity trends" (an approach we call a "directional" approach) and quantitative structure-activity relationships (QSAR) for a congeneric series of inhibitors: the benzo[f]perhydroisoindole (BPHI) series. Trends observed in the PCA showed that the descriptors used were relevant to describe our structural data set by clearly identifying two well-defined structural subclasses of inhibitors. D-Optimal design techniques allowed us to define a training set for PLS study in PP-space. Models were derived for each biological assay under evaluation: the in vitro Ki-Ras and cellular HCT116 tests. Each of these assay-based sets was subdivided once more into two subsets according to two structural classes in this BPHI series as revealed by the PCA model. The response surface modeling (RSM) methodology was used for each subset, and the corresponding RSM plots helped us identify "activity trends" exploited to guide further analogue design. For more precise activity predictions more refined PLS models on constrained PP-spaces were developed for each subset. This approach was validated with predicted sets and demonstrates that useful information can be extracted from just a few very informative and representative compounds. Finally, we also showed the potential use of such a strategy at an early stage of an optimization process to extract the first "activity trends" that might support decision making and guide medicinal chemists in the initial design of new analogues and/or lead followup libraries.
D-Optimal Designs, Partial Least Squares and Response Surface Modeling to analyse Farnesyl transf... more D-Optimal Designs, Partial Least Squares and Response Surface Modeling to analyse Farnesyl transferase inhibitors, 13th European Symposium on Quantitative Structure-Activity Relationships
Biochemistry, 2003
The telomeric G-rich single-stranded DNA can adopt in vitro an intramolecular quadruplex structur... more The telomeric G-rich single-stranded DNA can adopt in vitro an intramolecular quadruplex structure, which has been shown to directly inhibit telomerase activity. The reactivation of this enzyme in immortalized and most cancer cells suggests that telomerase is a relevant target in oncology, and telomerase inhibitors have been proposed as new potential anticancer agents. In this paper, we have analyzed the selectivity of four ethidium derivatives and ethidium itself toward different G-quadruplex species, with electrospray mass spectrometry and competitive equilibrium dialysis and evaluated their inhibitory properties against telomerase. A selectivity profile may be obtained through electrospray ionization mass spectrometry (ESI-MS), which is in fair agreement with competitive equilibrium dialysis data. It also provides unambiguous data on the number of binding sites per nucleic acid (maximal number of two ethidium derivatives per quadruplex, in agreement with external stacking). Our e...
Farnesyltransferase Inhibitors in Cancer Therapy, 2000
Nucleic Acids Research, 2013
The triazine derivative 12459 is a potent G-quadruplex ligand that triggers apoptosis or delayed ... more The triazine derivative 12459 is a potent G-quadruplex ligand that triggers apoptosis or delayed growth arrest, telomere shortening and G-overhang degradation, as a function of its concentration and time exposure to the cells. We have investigated here the DNA damage response induced by 12459 in A549 cells. Submicromolar concentrations of 12459 triggers a delayed Chk1-ATR-mediated DNA damage response associated with a telomeric dysfunction and a G2/M arrest. Surprisingly, increasing concentrations of 12459 leading to cell apoptosis induced a mechanism that bypasses the DNA damage signaling and leads to the dephosphorylation of Chk1 and c-H2AX. We identified the phosphatase Protein Phosphatase Magnesium dependent 1D/Wild-type P53-Induced Phosphatase (PPM1D/WIP1) as a factor responsible for this dephosphorylation. SiRNA-mediated depletion of PPM1D/WIP1 reactivates the DNA damage signaling by 12459. In addition, PPM1D/WIP1 is activated by reactive oxygen species (ROS) induced by 12459. ROS generated by 12459 are sufficient to trigger an early DNA damage in A549 cells when PPM1D/WIP1 is depleted. However, ROS inactivation by N-acetyl cysteine (NAC) treatment does not change the apoptotic response induced by 12459. Because PPM1D expression was recently reported to modulate the recruitment of DNA repair molecules, our data would suggest a cycle of futile protection against 12459, thus leading to a delayed mechanism of cell death.
Cellular and Molecular Life Sciences, 2012
Functional telomeres are protected from nonhomologous end-joining (NHEJ) and homologous recombina... more Functional telomeres are protected from nonhomologous end-joining (NHEJ) and homologous recombination (HR) DNA repair pathways. Replication is a critical period for telomeres because of the requirement for reconstitution of functional protected telomere conformations, a process that involves DNA repair proteins. Using knockdown of DNA-PKcs and Rad51 expression in three different cell lines, we demonstrate the respective involvement of NHEJ and HR in the formation of telomere aberrations induced by the G-quadruplex ligand 360A during or after replication. HR contributed to specific chromatid-type aberrations (telomere losses and doublets) affecting the lagging strand telomeres, whereas DNA-PKcs-dependent NHEJ was responsible for sister telomere fusions as a direct consequence of G-quadruplex formation and/or stabilization induced by 360A on parental telomere G strands. NHEJ and HR activation at telomeres altered mitotic progression in treated cells. In particular, NHEJmediated sister telomere fusions were associated with altered metaphase-anaphase transition and anaphase bridges and resulted in cell death during mitosis or early G1. Collectively, these data elucidate specific molecular and cellular mechanisms triggered by telomere targeting by the G-quadruplex ligand 360A, leading to cancer cell death. Keywords Rad51 Á DNA-PKcs Á G-quadruplex Á Telomere Á Mitosis Abbreviations NHEJ Non-homologous end-joining HR Homologous recombination DMSO Dimethyl sulfoxide Telo-FISH Telomere-fluorescent in situ hybridization CO-FISH Chromosome orientation-FISH Electronic supplementary material The online version of this article (
Tetrahedron letters, 2004
Isoxazole derivatives Isoxazole derivatives R 0240 1,3-Dipolar Cycloaddition Route to Novel Isoxa... more Isoxazole derivatives Isoxazole derivatives R 0240 1,3-Dipolar Cycloaddition Route to Novel Isoxazole-Type Derivatives Related to Combretastatin A-4.-1,3-Dipolar cycloaddition of various 3,4,5-trimethoxyphenyl units with the nitrile oxide in situ generated from aryloxime (II) gives isoxazole-type heterocycles related to the potent anticancer drug combretastin.
European Journal of Medicinal Chemistry
Anti-cancer drug design
In order to obtain non-degradable and more potent protein-tyrosine kinase inhibitors, derived fro... more In order to obtain non-degradable and more potent protein-tyrosine kinase inhibitors, derived from the 5-(2,5-dihydroxybenzyl)-aminosalicylates already described, we have developed a new series of 5-(2,5-dihydroxybenzyl)phenylamines. The compounds, diversely substituted on the phenyl ring by alcohol, nitrile, ether, ketone, amide and thioamide groups, were tested for their ability to inhibit epidermal growth factor (EGF) receptor-associated tyrosine kinase activity in vitro. They inhibit the phosphorylation of the peptide substrate RR-Src by the EGF receptor purified from ER 22 cells, with IC50 values in the range 0.02-0.45 microns. Several of these compounds inhibit EGF-dependent DNA synthesis in ER 22 cells with IC50 values of around 1 micron and furthermore their inhibition has been found to be specific for various protein kinases.
Anti-cancer drug design
A series of platinum dichloroethylenediamine complexes [PtCl2(R-en)] bearing a side chain on one ... more A series of platinum dichloroethylenediamine complexes [PtCl2(R-en)] bearing a side chain on one carbon atom of the ethylenediamine ligand, with or without a functional group on the side chain, have been prepared and investigated for antitumor activity against L1210 leukemia. They were tested both in vitro, with cisplatin-sensitive and resistant cell lines, and in vivo, with cisplatin-sensitive and resistant tumors grafted i.p. in B6D2F1 mice. The rationale for this study was to test how charge, polarity and shape of the R side chain influence antitumor activity. Complexes carrying one or more ammonium groups on the side chain were all inactive. Derivatives with a carbamate function attached by the nitrogen atom, via a methylene group, to the ethylenediamine moiety ('N-bound' carbamate) were highly active in vitro and in vivo. The best results were obtained with these carbamates bearing hydrophobic substituents of intermediate size. Replacement of N-bound by O-bound carbamat...
Inhibiteurs de telomerase et conséquences pour la thérapeutique anti-cancéreuse
Proceedings of the National Academy of Sciences, 2002
Nucleic Acids Research, 2004
Ligand 12459, a potent G-quadruplex-interacting agent that belongs to the triazine series, was pr... more Ligand 12459, a potent G-quadruplex-interacting agent that belongs to the triazine series, was previously shown to downregulate telomerase activity in the human A549 lung carcinoma cell line. We show here that the downregulation of telomerase activity is caused by an alteration of the hTERT splicing pattern induced by 12459, i.e. an almost complete disappearance of the active (+a,+b) transcript and an over-expression of the inactive ±b transcript. Spliced intron 6 forming the ±b hTERT transcript contained several tracks of G-rich sequences able to form G-quadruplexes. By using a speci®c PCR-stop assay, we show that 12459 is able to stabilize the formation of these G-quadruplex structures. A549 cell line clones selected for resistance to 12459 have been analyzed for their hTERT splicing pattern. Resistant clones are able to maintain the active hTERT transcript under 12459 treatment, suggesting the appearance of mechanisms able to bypass the 12459-induced splicing alterations. In contrast to 12459, telomestatin and BRACO19, two other G-quadruplex-interacting agents, have no effect on the hTERT splicing pattern in A549 cells, are cytotoxic against the A549resistant clones and display a lower ef®ciency to stabilize hTERT G-quadruplexes. These results lead us to propose that 12459 impairs the splicing machinery of hTERT through stabilization of quadruplexes located in the hTERT intron 6. Differences of selectivity between 12459, BRACO19 and telomestatin for these hTERT quadruplexes may be important to explain their respective activity and inactivity against hTERT splicing.
The Journal of Organic Chemistry, 2001
Nucleic acids symposium series (2004), 2008
The binding properties of a series of known G-quadruplex ligands have been studied by ESI-MS expe... more The binding properties of a series of known G-quadruplex ligands have been studied by ESI-MS experiments. The tetramolecular (TG(4)T)(4) quadruplex and its analogues I and II blocked, respectively, at the 3' or 5'-end by a tetra-end-linker (TEL) unit were chosen as the ligands targets. The stoichiometries of the obtained complexes as well as the ligand affinity and selectivity to the different quadruplexes were determined to deduce the ligand binding site. The TEL derivatives I and II allowed the probing of the grooves contribution to the binding of ligands to G-quadruplexes, demonstrating that the 3' and 5' quartets are not equivalent binding sites for ligand end-stacking.
Nucleic Acids Research, Jul 21, 2005
The G-overhangs of telomeres are thought to adopt particular conformations, such as T-loops or G-... more The G-overhangs of telomeres are thought to adopt particular conformations, such as T-loops or G-quadruplexes. It has been suggested that G-quadruplex structures could be stabilized by specific ligands in a new approach to cancer treatment consisting in inhibition of telomerase, an enzyme involved in telomere maintenance and cell immortality. Although the formation of G-quadruplexes was demonstrated in vitro many years ago, it has not been definitively demonstrated in living human cells. We therefore investigated the chromosomal binding of a tritiated G-quadruplex ligand, 3 H-360A (2,6-N,N 0-methyl-quinolinio-3-yl)-pyridine dicarboxamide [methyl-3 H]. We verified the in vitro selectivity of 3 H-360A for G-quadruplex structures by equilibrium dialysis. We then showed by binding experiments with human genomic DNA that 3 H-360A has a very potent selectivity toward G-quadruplex structures of the telomeric 3 0-overhang. Finally, we performed autoradiography of metaphase spreads from cells cultured with 3 H-360A. We found that 3 H-360A was preferentially bound to chromosome terminal regions of both human normal (peripheral blood lymphocytes) and tumor cells (T98G and CEM1301). In conclusion, our results provide evidence that a specific G-quadruplex ligand interacts with the terminal ends of human chromosomes. They support the hypothesis that G-quadruplex ligands induce and/or stabilize G-quadruplex structures at telomeres of human cells.
Biochemical and Biophysical Research Communications, 2004
A parallel G-quadruplex structure was recently identified in the NHE III 1 element of the c-myc g... more A parallel G-quadruplex structure was recently identified in the NHE III 1 element of the c-myc gene promoter that functioned as a transcriptional repressor. Different series of telomeric G-quadruplex interacting ligands reported to block telomerase activity were evaluated in a new PCR stop assay on the c-myc quadruplex (Pu22myc). Results indicated that the cationic porphyrin TMPyP4 previously described to stabilize c-myc quadruplex and to cause transcription inhibition efficiently inhibited the assay but with a narrow selectivity when parallel experiments were performed with an oligonucleotide (Pu22mu) containing mutations in the guanine repeat which is unable to form a quadruplex. Other ligands presented potent inhibitory properties with IC 50 in the submicromolar range. 307A, a new 2,6-pyridin-dicarboxamide derivative was found to present the highest selectivity as compared to Pu22mu oligonucleotide (>90-fold). Comparison with telomeric G-quadruplex using TRAP-G4 and PCR stop assays also indicated that ligands 307A, telomestatin, and TMPyP4 are equipotent against both c-myc and telomeric sequences while other ligands displayed some partial selectivity (2-to 6-fold) towards one of these sequences. This work provides evidence that G-quadruplex ligands reported as telomerase inhibitors efficiently stabilized c-myc promoter intramolecular quadruplex and may also potentially be used to inhibit c-myc gene transcription in tumor cells.
Journal of Medicinal Chemistry, 2000
We have investigated the combined use of partial least squares (PLS) and statistical design princ... more We have investigated the combined use of partial least squares (PLS) and statistical design principles in principal property space (PP-space), derived from principal component analysis (PCA), to analyze farnesyltransferase inhibitors in order to identify "activity trends" (an approach we call a "directional" approach) and quantitative structure-activity relationships (QSAR) for a congeneric series of inhibitors: the benzo[f]perhydroisoindole (BPHI) series. Trends observed in the PCA showed that the descriptors used were relevant to describe our structural data set by clearly identifying two well-defined structural subclasses of inhibitors. D-Optimal design techniques allowed us to define a training set for PLS study in PP-space. Models were derived for each biological assay under evaluation: the in vitro Ki-Ras and cellular HCT116 tests. Each of these assay-based sets was subdivided once more into two subsets according to two structural classes in this BPHI series as revealed by the PCA model. The response surface modeling (RSM) methodology was used for each subset, and the corresponding RSM plots helped us identify "activity trends" exploited to guide further analogue design. For more precise activity predictions more refined PLS models on constrained PP-spaces were developed for each subset. This approach was validated with predicted sets and demonstrates that useful information can be extracted from just a few very informative and representative compounds. Finally, we also showed the potential use of such a strategy at an early stage of an optimization process to extract the first "activity trends" that might support decision making and guide medicinal chemists in the initial design of new analogues and/or lead followup libraries.
D-Optimal Designs, Partial Least Squares and Response Surface Modeling to analyse Farnesyl transf... more D-Optimal Designs, Partial Least Squares and Response Surface Modeling to analyse Farnesyl transferase inhibitors, 13th European Symposium on Quantitative Structure-Activity Relationships