Synthesis of amide and sulfonamide substituted N-aryl 6-aminoquinoxalines as PFKFB3 inhibitors with improved physicochemical properties.

In oncology, the "Warburg effect" describes the elevated production of energy by glycolysis in cancer cells. The ubiquitous and hypoxia-induced 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 3 (PFKFB3) plays a noteworthy role in the regulation of glycolysis by producing fructose-2,6-biphosphate (F-2,6-BP), a potent activator of the glycolysis rate-limiting phosphofructokinase PFK-1. Series of amides and sulfonamides derivatives based on a N-aryl 6-aminoquinoxaline scaffold were synthesized and tested for their inhibition of PFKFB3 in vitro in a biochemical assay as well as in HCT116 cells. The carboxamide series displayed satisfactory kinetic solubility and metabolic stability, and within this class, potent lead compounds with low nanomolar activity have been identified with a suitable profile for further in vivo evaluation.

5-Keto-3-cyano-2,4-diaminothiophenes as selective maternal embryonic leucine zipper kinase inhibitors.

Maternal embryonic leucine zipper kinase (MELK) is involved in several key cellular processes and displays increased levels of expression in numerous cancer classes (colon, breast, brain, ovary, prostate and lung). Although no selective MELK inhibitors have yet been approved, increasing evidence suggest that inhibition of MELK would constitute a promising approach for cancer therapy. A weak high-throughput screening hit (17, IC50 ≈ 5 µM) with lead-like properties was optimized for MELK inhibition. The early identification of a plausible binding mode by molecular modeling offered guidance in the choice of modifications towards compound 52 which displayed a 98 nM IC50. A good selectivity profile was achieved for a representative member of the series (29) in a 486 protein kinase panel. Future elaboration of 52 has the potential to deliver compounds for further development with chemotherapeutic aims.

Discovery and Structure-Activity Relationships of N-Aryl 6-Aminoquinoxalines as Potent PFKFB3 Kinase Inhibitors.

Energy and biomass production in cancer cells are largely supported by aerobic glycolysis in what is called the Warburg effect. The process is regulated by key enzymes, among which phosphofructokinase PFK-2 plays a significant role by producing fructose-2,6-biphosphate; the most potent activator of the glycolysis rate-limiting step performed by phosphofructokinase PFK-1. Herein, the synthesis, biological evaluation and structure-activity relationship of novel inhibitors of 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 3 (PFKFB3), which is the ubiquitous and hypoxia-induced isoform of PFK-2, are reported. X-ray crystallography and docking were instrumental in the design and optimisation of a series of N-aryl 6-aminoquinoxalines. The most potent representative, N-(4-methanesulfonylpyridin-3-yl)-8-(3-methyl-1-benzothiophen-5-yl)quinoxalin-6-amine, displayed an IC50 of 14 nm for the target and an IC50 of 0.49 µm for fructose-2,6-biphosphate production in human colon carcinoma HCT116 cells. This work provides a new entry in the field of PFKFB3 inhibitors with potential for development in oncology.

A novel, dual pan-PIM/FLT3 inhibitor SEL24 exhibits broad therapeutic potential in acute myeloid leukemia.

Fms-like tyrosine kinase 3 internal tandem duplication (FLT3-ITD) is one of the most common genetic lesions in acute myeloid leukemia patients (AML). Although FLT3 tyrosine kinase inhibitors initially exhibit clinical activity, resistance to treatment inevitably occurs within months. PIM kinases are thought to be major drivers of the resistance phenotype and their inhibition in relapsed samples restores cell sensitivity to FLT3 inhibitors. Thus, simultaneous PIM and FLT3 inhibition represents a promising strategy in AML therapy. For such reasons, we have developed SEL24-B489 - a potent, dual PIM and FLT3-ITD inhibitor. SEL24-B489 exhibited significantly broader on-target activity in AML cell lines and primary AML blasts than selective FLT3-ITD or PIM inhibitors. SEL24-B489 also demonstrated marked activity in cells bearing FLT3 tyrosine kinase domain (TKD) mutations that lead to FLT3 inhibitor resistance. Moreover, SEL24-B489 inhibited the growth of a broad panel of AML cell lines in xenograft models with a clear pharmacodynamic-pharmacokinetic relationship. Taken together, our data highlight the unique dual activity of the SEL24-B489 that abrogates the activity of signaling circuits involved in proliferation, inhibition of apoptosis and protein translation/metabolism. These results underscore the therapeutic potential of the dual PIM/FLT3-ITD inhibitor for the treatment of AML.

Synthesis and pharmacological properties of new derivatives of 4-alkoxy-6-methyl-1H-pyrrolo[3,4-c]pyridine-1,3(2H)-diones.

Synthesis of 2-(2-hydroxy-3-amino)propyl derivatives of 4-alkoxy-6-methyl-1H-pyrrolo[3,4-c]pyridine-1,3(2H)-diones (24-35) is described. The chlorides used in the above synthesis exist mainly in the cyclic forms (18, 20-23). Only chloride with benzhydryl substituent at the nitrogen atom of piperazine has the chain structure (19). Among the studied imides the most active analgesics in the "writhing" syndrome test proved to be compounds 30 and 31 (with LD50 > 2000 mg/kg) containing 4-benzylpiperidino group. Furthermore, all imides suppressed significantly spontaneous locomotor activity of mice.

Synthesis and pharmacological properties of 1-[2-hydroxy-3-(4-o,m,p-halogenophenyl)- and 3-(4-m-chlorophenyl)-1-piperazinyl]propyl derivatives of amides of 7-methyl-3-phenyl-2,4-dioxo-1,2,3,4-tetrahydropyrido [2,3-d]pyrimidine-5-carboxylic acid with analgesic and sedative activities.

Synthesis of 1-[2-hydroxy-3-(4-o,m,p-halogenophenyl)- and 3-(4-m-chlorophenyl)-1-piperazinyl]propyl derivatives of amides of 7-methyl-3-phenyl-2,4-dioxo-1,2,3,4-tetrahydropyrido[2,3-d]pyrimidine-5-carboxylic acid (18, 20-23, 25, 27-30 and 19, 24, 26) is described. All substances were active as analgesic agents in "writhing syndrome" test and except of 18 and 23 they acted stronger than acetylsalicylic acid. All final derivatives tested significantly suppressed the spontaneous locomotor activity of mice.

Synthesis and properties of 4-alkoxy-2-[2-hydroxy-3-(4-o,m,p-halogenoaryl-1 -piperazinyl)propyl]-6-methyl-1H-pyrrolo-[3,4-c]pyridine-1,3(2H)-diones with analgesic and sedative activities.

Synthesis of N-substituted derivatives of 4-alkoxy-6-methyl-1H-pyrrolo[3,4-c]pyridine-1,3(2H)-diones (17-26) is described. The chlorides, containing OH group, used in the above synthesis can exist in two isomeric forms: chain (12, 14-16) and cyclic (12a, 14a-16a). All final imides studied exhibited analgesic activity in the "writhing syndrome" test which was superior than that of acetylsalicylic acid. In the "hot plate" test only two compounds (19, 20) were active as antinociceptive agents. Furthermore, all compounds tested significantly suppressed the spontaneous locomotor activity of mice.

HPLC and TLC methodology for determination or purity evaluation of 4-methoxy-2-(3(4-phenyl-1-piperazinyl))propyl-2,3-dihydro-6-methyl-1,3-dioxo-1H-pyrrolo[3,4-c]pyridine.

A UV spectrophotometric analysis of 4-methoxy-2-(3 (4-phenyl-1-piperazinyl)) propyl-2,3-dihydro-6-methyl-1,3-dioxo-1H-pyrrolo [3,4-c] pyridine (II) in HCI (0.01 mole/L) was performed by determining the values of specific absorption coefficients at the following analytical wavelengths: 225, 285 and 350 nm. The separation by means of TLC of compound II and of its five decomposition products was also studied. Silica gel coated plates (60 F254) were used and the mobile phase consisted of butanol--acetic acid--water. A validated RP-HPLC method for the determination or purity evaluation of II, with phenacetin as an internal standard, is described. The solution of II in HCI (0.01 mole/L) was chromatographed on an octadecyl column (LiChrosorb 100 RP-18 column 250 x 4.0 mm I.D., dp = 5 microm) using an eluent composed of the mixture acetonitrile--phosphate buffer pH = 2. Ultraviolet detection was used at an operation wavelength of 239 nm. The HPLC method was validated by determination of the following parameters: selectivity, precision, accuracy, linearity, stability of the analite, LOD and LOQ. Kinetic studies of the decomposition process of II in both acidic and alkaline environments demonstrated the instability of the imide group.

Synthesis and pharmacological properties of N,N-dialkyl(dialkenyl)amides of 7-methyl-3-phenyl-1-[2-hydroxy-3-(4-phenyl-1-piperazinyl)propyl]-2,4-dioxo-1,2,3,4-tetrahydropyrido[2,3-d]pyrimidine-5-carboxylic acid.

Synthesis of N,N-dialkyl(dialkenyl)amides of 7-methyl-3-phenyl-2,4-dioxo-1,2,3,4-tetrahydropyrido[2,3-d]pyrimidine-5-carboxylic acid (5-9) and their 1-[2-hydroxy-3-(4-phenyl-1-piperazinyl)propyl] derivatives (10-14) is described. Compounds 10-14 were tested for analgesic and sedative activities as well as for mu-opioid receptors binding affinities. All the amides, being the object of investigation, displayed an interesting analgesic action, which in case of the compounds 10-12 and 14 was superior to that of acetylsalicylic acid in two different tests. Furthermore all the amides (10-14) significantly suppressed the spontaneous locomotor activity, prolonged barbiturate sleep in mice and showed a weak affinity to mu-opioid receptors.

Investigations on the synthesis and pharmacological properties of 4-alkoxy-2-[2-hydroxy-3-(4-aryl-1-piperazinyl)propyl]-6-methyl-1H-pyrrolo[3,4-c]pyridine-1,3(2H)-diones.

Synthesis of 2-[2-hydroxy-3-(4-aryl-1-piperazinyl)propyl] derivatives of 4-alkoxy-6-methyl-1H-pyrrolo[3,4-c]pyridine-1,3(2H)-diones (8-12) is described. The chlorides used in the above synthesis can exist in two isomeric forms: chain (18-20) and cyclic (19a, 20a). The compounds 8-12 exhibited potent analgesic activity which was superior than that of acetylsalicylic acid in two different tests. Most of the investigated imides suppressed significantly spontaneous locomotor activity in mice.