Alain Pierre

In vitro cytotoxicity of s16020-2, a new olivacine derivative

SummaryS16020-2 is a new olivacine derivative which has recently shown a marked antitumor activity in various experimental models. This study was undertaken in order to measure the inhibition of the proliferation of various sensitive and resistant tumor cell lines, by S16020-2, and to obtain information concerning its mechanism of action.For a continuous exposure, S16020-2 was as cytotoxic as adriamycin (ADR) (mean IC50 of about 28 nM) and on average, 46 fold more potent than elliptinium acetate (ELP), against a panel of 20 non-multidrug resistant cell lines. With a short exposure (1 hour) followed by a post-incubation of 95 hours in drug-free medium, S16020-2 was 5 and 6 fold more cytotoxic than ADR for human lung A549 and murine melanoma B16 cells, respectively. Furthermore, S16020-2 inhibited more actively the formation of colonies issued from proliferating cells, compared to colonies issued from quiescent A549 cells. Because quiescent cells demonstrated a 3 fold lower level of topoisomerase IIα (topo II) than proliferating cells, these results suggest that this enzyme could be a potential target for S16020-2. In addition, as demonstrated by flow cytometric studies, S16020-2 intercalated into DNA and induced a cell cycle arrest in G2.Cell lines displaying the multidrug resistance (MDR) phenotype, P388/ADR-1, P388/ADR, P388/VCR-20, KB-A1, DC-3F/AD, S1/tMDR, and Colo320DM, were more sensitive to S16020-2 than to ADR or ELP, as shown by the mean resistance factors, 8, 201, and 23 respectively. In addition, the two cell lines displaying the pure classical MDR phenotype, linked exclusively to the P-glycoprotein (P-gp) overexpression (P388/VCR-20 and S1/tMDR), were as sensitive to S16020-2 as their sensitive parental counterparts, although they were resistant to ADR.S16020-2 is thus one of the most potent olivacine and ellipticine derivative yet characterized. The good cytotoxicity of S16020-2 against cells displaying a P-gp-mediated multidrug resistance, and its antitumor activity in vivo delineate an important chemotherapeutic potential for this drug.

In vitro and in vivo circumvention of multidrug resistance by Servier 9788, a novel triazinoaminopiperidine derivative.

SummaryS 9788 is a novel triazinoaminopiperidine derivative which does not belong to any of the classes of compounds known to reverse multidrug resistance (MDR). S 9788 was far more potent than verapamil (VRP) in reversing resistance to adriamycin (ADR) in the ADR-selected murine leukaemia cell lines P388/ADR-1 and P388/ADR-10, and the human chronic myelogenous leukaemia K562/R. Fold reversion with S 9788 (5μM was, respectively, 3.5, 5.4 and 11.3 times greater than that with VRP (5μM). S 9788 was also a more potent reversant of ADR resistance in the intrinsically resistant human colon adenocarcinoma COLO 320DM (2.3 fold), and of vincristine (VCR) resistance in the human MDR1 gene-transfected squamous lung carcinoma line S1/tMDR1 (5.6 fold). The activity of S 9788 depended on both the MDR cell line and the cytotoxic agent. S 9788 (50–100 mg/kg/d) administered IP once a day on days 1–4 resulted in a dose-dependent increase in the chemotherapeutic effect of VCR (0.25 mg/kg/d) in P388/VCR-bearing mice and ADR (4 mg/kg/d) in P388/ADR-bearing mice. Increases in antitumor activity were (% T/C) of +20–34% in the P388/ADR model and +50–78% in the P388/VCR model with respect to cytotoxic agent treatment alone. S 9788 appeared to be devoid of toxicity at its effective doses. The mechanism of action of S 9788 is unknown but S 9788 (0.5–10μM) induced a dose-dependent increase in ADR accumulation in KB-Al cells and compared to verapamil its effect was twice as active and approximately seven times more potent. We conclude that S 9788 is a novel agent capable of reversing MDRin vitro andin vivo, and whose pharmacological profile warrants its selection as a candidate drug for eventual assessment in the clinic.

Raman-Spectroscopy, X-Ray-Diffraction, And Phase Relationship Determinations With A Versatile Heating Cell For Measurements Up To 3600-K (Or 2700-K In Air)

A simple, rapid, and inexpensive heating-wire technique is used for physical observations at high temperatures. The upper limit is 2000 K in air with platinum-iridium or platinum-rhodium wires and 2700 K with iridium; temperatures up to 3600 K can be achieved under an inert atmosphere with tungsten wires. Raman spectroscopy measurements made up to 1900 K by this technique suggest that the high-temperature harmonic vibrational behavior of corundum (alpha-Al2O3) results from the cancellation of anharmonic effects. Powder x-ray diffraction experiments with synchrotron radiation show that perovskite (CaTiO3) changes from orthorhombic symmetry to cubic between 1330 and 1530 K, with an intermediate tetragonal phase likely, consistent with lambda-type transitions recorded by recent calorimetric measurements. Finally, observations of CaAl2Si2O8 polymorphism has shown the existence of a new metastable phase.

Effects of a new triazinoaminopiperidine derivative on adriamycin accumulation and retention in cells displaying P-glycoprotein-mediated multidrug resistance

A new triazinoaminopiperidine derivative, Servier 9788 (S9788), was investigated for its ability to increase Adriamycin (ADR) accumulation and retention in two rodent (P388/ADR and DC-3F/AD) and three human (KB-A1, K562/R and COLO 320DM) cell lines displaying the P-glycoprotein (P-gp)-mediated multidrug resistance (MDR) phenotype. Depending on the cell line S9788 was shown to be two to five times more active and five to 15 times more potent than Verapamil (VRP) in increasing ADR accumulation in resistant cells. ADR retention in KB-A1 cells maintained in a concentration of 10 microM S9788 was twice that in VRP-treated cells, and similar to that measured in the untreated sensitive KB-3-1 cells. Although 5 microM S9788 and 50 microM VRP gave the same values of ADR uptake in KB-A1 cells, S9788 was shown to induce a greater ADR retention following cell wash and post-incubation in resistance modifier- and ADR-free medium. Taking into account that S9788 had no effects on ADR accumulation and retention in sensitive KB-3-1 cells, it can be suggested that S9788 inhibits specifically the P-gp dependent ADR efflux, and in a manner less reversible than that observed with VRP. Moreover, [3H]azidopine photolabeling of P-gp, in P388/ADR plasma membranes, was completely inhibited by 100 microM S9788. Although S9788, as VRP, had no effect on the cell cycle of P388 cells, 5 microM S9788 increased 700-fold the efficacy of ADR to block P388/ADR cells in the G2+M phase of the cell cycle. Together, these results show that the sensitization, by S9788, of cell lines resistant to ADR is mainly due to an increase in ADR accumulation and retention, leading to an increase in the number of resistant cells blocked in the G2+M phase.

Design, synthesis and antiproliferative activity of tripentones: A new series of antitubulin agents

Structure-activity relationship studies of a new series of tripentones (thieno[2,3-b]pyrrolizin-8-ones), led us to prepare several derivatives with antiproliferative activities. The most promising 3-(3-hydroxy-4-methoxyphenyl)thieno[2,3-b]pyrrolizin-8-one 20 (leukemia L1210, IC(50)=15 nM) was shown to be a potent inhibitor of tubulin polymerization.

Synthesis and antiproliferative evaluation of 7-aminosubstituted pyrroloiminoquinone derivatives.

Coupling of five amines on the 7-methoxy-1,3,4,5-tetrahydropyrrolo[4,3,2-de]quinoline core was achieved and afforded, in particular, an opened analogue of the natural alkaloid wakayin. Evaluation of cytotoxic activity of compounds 2, 10-13 on L1210 cells afforded IC50 in the range 0.25 5.3 microM.

In vivo antitumor activity of S 16020-2, a new olivacine derivative.

Abstract The antitumor activity of S 16020-2, a new olivacine derivative, was investigated in vivo and compared with that of Adriamycin and elliptinium acetate in a panel of murine (P388 leukemia, M5076 sarcoma, Lewis lung carcinoma, and B16 melanoma) and human (NCI-H460 non-small-cell lung and MCF7 breast carcinomas) tumor models. S 16020-2 given i.v. was active against P388 leukemia implanted i.p., s.c., or intracerebrally. The therapeutic effect of an intermittent schedule (administration on days 1, 5, 9) was superior to that of single-dose treatment, allowing the i.v. administration of high total doses of S 16020-2 and resulting in the cure of 60% of mice in the i.p. P388 model. In this model, S 16020-2 was more active than elliptinium acetate and showed a better therapeutic index than Adriamycin:≥8 versus 2. A good therapeutic effect of S 16020-2 was also observed in three P388 leukemia sublines displaying the classic multidrug-resistance phenotype, namely, P388/VCR, P388/VCR-20, and P388/MDRC.04, the latter being totally insensitive to vincristine and Adriamycin. However, S 16020-2 was not active against the P388/ADR leukemia, a model highly resistant to adriamycin in vivo. S 16020-2 was both more active than Adriamycin and curative in the M5076 sarcoma and Lewis lung carcinoma implanted s.c. In the B16 melanoma implanted i.p. or s.c., S 160202 was less active than Adriamycin. Against the NCI-H460 human tumor xenograft, S 16020-2 demonstrated activity superior to that of Adriamycin (T/C=20% versus 43% on day 21). Against the MCF7 breast cancer xenograft, S 16020-2 was active, but less so than Adriamycin (T/C=23% versus 9% on day 21), whereas elliptinium acetate was marginally active (T/C=49% on day 24). The hematological toxicity of S 16020-2 given to B6D2F1 mice at pharmacological dose appeared to be less severe than that of Adriamycin, particularly in bone-marrow stem cells. These results demonstrate that S 16020-2 is a highly active antitumor drug in various experimental tumor models and is markedly more efficient than elliptinium acetate. Because of its pharmacological profile, which is globally different from that of Adriamycin, S 16020-2 is considered an interesting candidate for clinical trials.

Synthesis and biological activities of indolocarbazoles bearing amino acid residues.

Three indolocarbazole compounds bearing a tripeptide or a lysine group attached to one of the indole nitrogens via a propylamino chain and two rebeccamycin derivatives bearing a lysine residue on the sugar moiety were synthesised with the aim of improving the binding to DNA and the antiproliferative activities. Four tumour cell lines, from murine L1210 leukemia, human HT29 colon carcinoma, A549 non-small cell lung carcinoma and K-562 leukemia, were used to evaluate the cytotoxicity of the drugs. Their effects on the cell cycle of L1210 cells and their antimicrobial properties against two Gram-positive bacteria Bacillus cereus and Streptomyces chartreusis, a Gram-negative bacterium Escherichia coli and a yeast Candida albicans were also investigated.

Circumvention of P-glycoprotein-mediated multidrug resistance by S16020-2 : kinetics of uptake and efflux in sensitive and resistant cell lines

Purpose: In contrast to Adriamycin (ADR), the novel olivacine derivative S16020-2 has demonstrated potent antitumor activity in vitro and in vivo against cell lines displaying the P-glycoprotein (Pgp)-mediated multidrug-resistance phenotype (MDR), suggesting that this compound is not transported by Pgp. The purpose of this work was to study the accumulation of S16020-2 in Pgp-overexpressing cells. Methods: The kinetics of accumulation and retention of radiolabeled S16020-2 and ADR in sensitive KB-3-1, P388, and S1 cells and their resistant counterparts KB-A1, P388/VCR-20, and S1/tMDR cells were investigated. Results: The rates of efflux of S16020-2 and ADR were similar and were higher in KB-A1 cells than in KB-3-1 cells. A modulator of MDR, S9788, inhibited the efflux of both compounds only in KB-A1 cells. These results demonstrate that S16020-2 is effectively transported by Pgp overexpressed by KB-A1 cells with an efficiency close to that of ADR. A similar conclusion was obtained with the P388/VCR-20 cell line. In addition, the initial rate of uptake and the accumulation of S16020-2 were markedly higher than those of ADR in the cell lines tested. Conclusions: The cytotoxic potency of S16020-2 toward tumor cells overexpressing Pgp is thus likely to be due to its rapid rate of uptake, which bypasses Pgp and thus leads to a high cellular accumulation.

Synthesis of New Aromatic Pyrrolo[2,1- c] [1,4]benzodiazepines and Pyrrolo[1,2- a] thieno[3,2- e] [1,4]diazepines as Anti-tumoral Agents

Diazepine analogs of thieno[2,3- b] pyrrolizin-8-ones were synthesized by aromatization of 2-hydroxypyrrolo[1,2- a] thieno[3,2- e] [1,4]diazepines. These compounds were evaluated in vitro for their antiproliferative activity against the L1210 leukemia cell line. The activity of these compounds was in the micromolar range, the best result being for the mixture of the isomers 5 and 6 which showed a 0.35 μM IC 50 against cell growth.