New imidazo[1,2-a]quinoxaline derivatives: Synthesis and in vitro activity against human melanoma

International audienceNew imidazo[1,2-a]quinoxaline analogues have been synthesized in good yields via a bimolecular condensation of 2-imidazole carboxylic acid, followed by a coupling with ortho-fluoroaniline and subsequent substitution on the imidazole ring by Suzuki Cross-coupling reaction using microwave assistance. Antitumor activities of these derivatives were evaluated by growth inhibition of A375 cells in vitro. All compounds exhibited high activities compared to imiquimod and fotemustine used as references

Pharmacology of EAPB0203, a novel imidazo[1,2-a]quinoxaline derivative with anti-tumoral activity on melanoma

International audienceIn spite of the development of new anticancer drugs by the pharmaceutical industry, melanoma and T lymphomas are diseases for which medical advances remain limited. Thus, there was an urgent need of new therapeutics with an original mechanism of action. Since several years, our group develops quinox-alinic compounds. In this paper, the first preclinical results concerning one lead compound, EAPB0203, are presented. This compound exhibits in vitro cytotoxic activity on A375 and M4Be human melanoma cell lines superior to that of imiquimod and fotemustine. A liquid chromatography-mass spectrometry method was first validated to simultaneously quantify EAPB0203 and its metabolite, EAPB0202, in rat plasma. Thereafter, the pharmacokinetic profiles of EAPB0203 were studied in rat after intravenous and intraperitoneal administrations. After intraperitoneal administration the absolute bioavailability remains limited (22.7%). In xenografted mouse, after intraperitoneal administration of 5 and 20 mg/kg, EAPB0203 is more potent than fotemustine. The survival time was increased up to 4 and 2 weeks compared to control mice and mice treated by fotemustine, respectively. The results of this study demonstrate the relationship between the dose of EAPB0203 and its effects on tumor growth. Thus, promising efficacy, tolerance and pharmacokinetic data of EAPB0203 encourage the development towards patient benefit

Imidazo[1,2-<i>a</i>]quinoxalines Derivatives Grafted with Amino Acids: Synthesis and Evaluation on A375 Melanoma Cells

Imiqualines (imidazoquinoxaline derivatives) are anticancer compounds with high cytotoxic activities on melanoma cell lines. The first generation of imiqualines, with two lead compounds (EAPB0203 and EAPB0503), shows remarkable in vitro (IC50 = 1 570 nM and IC50 = 200 nM, respectively, on the A375 melanoma cell line) and in vivo activity on melanoma xenografts. The second generation derivatives, EAPB02302 and EAPB02303, are more active, with IC50 = 60 nM and IC50 = 10 nM, respectively, on A375 melanoma cell line. The aim of this study was to optimize the bioavailability of imiqualine derivatives, without losing their intrinsic activity. For that, we achieved chemical modulation on the second generation of imiqualines by conjugating amino acids on position 4. A new series of twenty-five compounds was efficiently synthesized by using microwave assistance and tested for its activity on the A375 cell line. In the new series, compounds 11a, 9d and 11b show cytotoxic activities less than second generation compounds, but similar to that of the first generation ones (IC50 = 403 nM, IC50 = 128 nM and IC50 = 584 nM, respectively). The presence of an amino acid leads to significant enhancement of the water solubility for improved drugability

Agonist and antagonist ligands of toll-like receptors 7 and 8: Ingenious tools for therapeutic purposes

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Méthylation des composés de type imidazopyrazine, imidazoquinoxaline et pyrazoloquinoxaline par couplage croisé de Suzuki – Miyaura

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IKK inhibitory activities of imidazo[1,2-a]pyrazine, imidazo[1,2-a]quinoxaline, imidazo[1,5-a]quinoxaline and pyrazolo[1,5-a]quinoxaline derivatives.

International audienceThe transcription factor NF-κB plays a key role in multiple cellular processes, including immune signaling, inflammation, development, proliferation and survival. Dysregulated NF-κB activation is associated with autoimmunitya, chronic inflammationb and cancerc. Activation of NF-κB requires IκB kinases IKKα and IKK β, therefore, targeting the activation of NF-κB-dependent pathway by IKK inibitors is becoming an increasingly popular avenue for the development of novel therapeutic interventions for inflammation and cancer and many pharmaceutical companies are developing inhibitors that target IKK. BMS-345541 (4(2'-aminoethyl)amino-1,8-dimethylimidazo(1,2-a)quinoxaline) was identified as a selective inhibitor of the catalytic subunits of IKK (IKK2: IC50= 0.3 μM, IKK1: IC50 = 4 μM)d. The aim of this study is to obtain new IKK inhibitors, analogues of BMS-345541. For this purpose, we have synthesized a variety of compounds diversely substituted belonging to four chemical series: imidazo[1,2-a]pyrazine, imidazo[1,2-a]quinoxaline, imidazo[1,5-a]quinoxaline and pyrazolo[1,5-a]quinoxaline. Their biological activities as potential IKK1 and IKK2 inhibitors are describede. Four strategies of synthesis are developed to obtain a variety of compounds with short reaction times by using micro-wave assistance. The preparation of these compounds is particularly simple and is carried out in good yields

IKK inhibitory activities of imidazo[1,2-a]pyrazine, imidazo[1,2-a]quinoxaline, imidazo[1,5-a]quinoxaline and pyrazolo[1,5-a]quinoxaline derivatives

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EAPB0503, a novel imidazoquinoxaline derivative, inhibits growth and induces apoptosis in chronic myeloid leukemia cells

International audienceImatinib, the first-generation tyrosine kinase inhibitor, revolutionized the therapeutic management of chronic myeloid leukemia (CML) and is highly effective in inducing remissions and prolonging the survival of CML patients. However, one-third of patients develop intolerance or resistance to treatment, and CML stem cells remain insensitive to this therapy, leading almost inevitably to relapse upon treatment discontinuation. Imidazoquinoxalines are imiquimod derivatives that induce growth inhibition and induction of caspase-dependent apoptosis in melanoma and T-cell lymphoma cells. We investigated the effects of EAPB0203 and EAPB0503, two novel imidazoquinoxaline derivatives, on human CML cell lines and showed that they induced a dose-dependent and time-dependent cell growth inhibition. EAPB0503 proved more potent and induced a specific cell cycle arrest in mitosis in CML cells and direct activation of apoptosis as evidenced by increased pre-G0 population, breakdown of mitochondrial membrane potential, PARP cleavage, and DNA breakage. Interestingly, EAPB0503 decreased BCR-ABL oncoprotein levels. The combination of EAPB0503 with imatinib synergized to inhibit the proliferation of CML cells, and most importantly, EABP0503 inhibited the proliferation of imatinib-resistant CML cells, offering promising therapeutic modalities that would circumvent resistance to tyrosine kinase inhibitors and improve the prognosis of CML

Structural characterization of in vitro metabolites of the new anticancer agent EAPB0503 by liquid chromatography–tandem mass spectrometry

International audienceEAPB0503, belonging to the imidazo[1,2-a]quinoxaline series, is an anticancer drug with antitumoral activity against a variety of tumors. Previous studies have shown that this drug undergoes demethylation and oxygenation reactions. In this paper, liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) was employed to assess the structures of unknown oxygenated metabolites of EAPB0503. EAPB0503 and its identified demethylated metabolites, EAPB0502 and EAPB0603, were incubated with human, rat, dog and mouse liver microsomes, as well as human, rat and dog hepatocytes. After separation on a C8 analytical column with a gradient elution of acetonitrile-formate buffer, positive ESI-MS/MS experiments were performed. To facilitate metabolite identification, the detailed fragmentation pathways of the parent compounds were first studied using high-resolution MS/MS. Additional hydrogen/deuterium exchange LC-MS/MS experiments were used to support the identification and structural characterization of metabolites. Four hydroxylated metabolites were identified: M'4 and its demethylated derivative M'1 (OH in ortho position on the phenyl substituent in position 1), and M'6 and its demethylated derivative M'3 (OH on the imidazole ring at the C2 position). Three phase II metabolites (Met A, EAPB0602 glucuronide; Met B, M'4 glucuronide; Met C, EAPB0603 glucuronide) were also evidenced. Elucidation of the metabolite structures was performed by comparing the chromatographic behaviors (changes in retention times), by measuring the molecular masses (mass increment), by studying the MS(2) spectral patterns of metabolites with those of parent drugs and for M'1 and M'4 by co-analysis with synthetic standards. The results of the present study provided important structural information relating to the metabolism of EAPB0503

Development of Imidazo[1,2-a]quinoxaline and Pyrazolo[1,5-a]quinoxaline series to obtain new IKK inhibitors

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