Synthesis and biological evaluation of 1H-pyrrolo[3,2-g]isoquinolines.

A structure-activity relationship study performed on 1H-pyrrolo[3,2-g]isoquinoline scaffold identified new haspin inhibitors with nanomolar potencies and selectivity indices (SI) over 6 (inhibitory potency evaluated against 8 protein kinases). Compound 22 was the most active of the series (haspin IC50 = 76 nM). Cellular evaluation of 22 confirmed its activity for endogenous haspin in U-2 OS cells and its anti-proliferative activity against various cell lines. In addition, the binding mode of analog 22 in complex with haspin was determined by X-ray crystallography.

Synthesis of new pyrazolo[4,3-a]phenanthridine Pim-1 inhibitors and evaluation of their cytotoxic activity towards the MOLM-13 acute myeloid leukemia cell line.

We synthesized new analogues of the anti-AML agent VS-II-173. We studied the effect of the substitution at the 1- and 5-positions of the pyrazolo[4,3-a]phenanthridine scaffold on Pim-1 kinase inhibition and cytotoxicity against AML MOLM-13 cells. We found that compounds 20 and 21, substituted at the 1-position exhibited stronger Pim-1 inhibition together with a high potency toward MOLM-13 cells, associated with apoptosis induction and selectivity over non-cancerous NRK cells.

Synthesis and Kinase Inhibitory Potencies of Pyrazolo[3,4-g]isoquinolines.

A new series of pyrazolo[3,4-g]isoquinoline derivatives, diversely substituted at the 4- or 8-position, were synthesized. The results of the kinase inhibitory potency study demonstrated that the introduction of a bromine atom at the 8-position was detrimental to Haspin inhibition, while the introduction of an alkyl group at the 4-position led to a modification of the kinase inhibition profiles. Altogether, the results obtained demonstrated that new pyrazolo[3,4-g]isoquinolines represent a novel family of kinase inhibitors with various selectivity profiles.

Recent Advances in Pain Management: Relevant Protein Kinases and Their Inhibitors.

The purpose of this review is to underline the protein kinases that have been established, either in fundamental approach or clinical trials, as potential biological targets in pain management. Protein kinases are presented according to their group in the human kinome: TK (Trk, RET, EGFR, JAK, VEGFR, SFK, BCR-Abl), CMGC (p38 MAPK, MEK, ERK, JNK, ASK1, CDK, CLK2, DYRK1A, GSK3, CK2), AGC (PKA, PKB, PKC, PKMζ, PKG, ROCK), CAMK, CK1 and atypical/other protein kinases (IKK, mTOR). Examples of small molecule inhibitors of these biological targets, demonstrating an analgesic effect, are described. Altogether, this review demonstrates the fundamental role that protein kinase inhibitors could play in the development of new pain treatments.

Kinase inhibitions in pyrido[4,3-h] and [3,4-g]quinazolines: Synthesis, SAR and molecular modeling studies.

New pyrido[3,4-g]quinazoline derivatives were prepared and evaluated for their inhibitory potency toward 5 protein kinases (CLK1, DYRK1A, GSK3, CDK5, CK1). A related pyrido[4,3-h]quinazoline scaffold with an angular structure was also synthesized and its potency against the same protein kinase panel was compared to the analogous pyrido[3,4-g]quinazoline. Best results were obtained for 10-nitropyrido[3,4-g]quinazoline 4 toward CLK1 with nanomolar activities.

Synthesis and preliminary in vitro kinase inhibition evaluation of new diversely substituted pyrido[3,4-g]quinazoline derivatives.

The synthesis of new diversely substituted pyrido[3,4-g]quinazolines is described. The inhibitory potencies of prepared compounds toward a panel of five CMGC protein kinases (CDK5, CLK1, DYRK1A, CK1, GSK3), that are known to play a potential role in Alzheimer's disease, were evaluated. The best overall kinase inhibition profile was found for nitro compound 4 bearing an ethyl group at the 5-position.

Synthesis and biological activity of pyrazole analogues of the staurosporine aglycon K252c.

A derivative of the staurosporine aglycon (K252c), in which the lactam ring was replaced by a pyrazole moiety, was synthesized. The resulting indolopyrazolocarbazole (3) inhibited Pim isoforms 1-3 whereas it did not impair the activity of two known targets of K252c, protein kinase C isoforms α and γ. Compound 3 exhibited moderate cytotoxic activity toward human leukemia and colon carcinoma cell lines (K562 and HCT116), strongly suggesting that this new scaffold deserves further investigations for treatment of malignancies associated with Pim activity.

Synthesis and activities of new indolopyrrolobenzodiazepine derivatives toward acute myeloid leukemia cells.

The synthesis of new indolopyrrolobenzodiazepine derivatives is described. Six compounds were selected for evaluation of cytotoxicity towards acute myeloid leukemia (AML) cells and normal fibroblasts. One compound (29) showed selective AML cell death induction. Its action was only partly overcome by knock-down of p53 or Bcl-2 overexpression, suggesting a strong activation of intrinsic apoptotic pathways.

Synthesis of pyrazolo[4,3-a]phenanthridines, a new scaffold for Pim kinase inhibition.

A new series of nitro or amino substituted pyrazolo[4,3-a]phenanthridines was synthesized in 6 steps from 5-bromo-6-nitroindazole. The evaluation of their inhibitory potency toward Pim kinases demonstrated that the nitro series could be considered as an interesting starting point for the development of new Pim kinase inhibitors, especially Pim-3. A preferential binding mode was suggested by molecular modeling experiments for nitro series and Pim-1/Pim-3 ATP-binding sites. Moreover, the most active compounds exhibited antiproliferative activities toward PC3 cells in the micromolar range.

New N-1,N-10-bridged pyrrolo[2,3-a]carbazole-3-carbaldehydes: synthesis and biological activities.

The synthesis of new pyrrolocarbazoles substituted at N-1/N-10 positions is described. All the compounds tested demonstrated moderate to high Pim-1/Pim-3 kinase inhibitory potency. The most active inhibitors identified in this series (3, 17) have an alkyl chain bridging the N-1 and N-10 positions. These compounds (3, 17) exhibited apoptosis-inducing activity toward acute myeloid leukemia IPC-81 cells, but not toward normal fibroblasts.

Synthesis, kinase inhibition and anti-leukemic activities of diversely substituted indolopyrazolocarbazoles.

Pyrazole analogues of the staurosporine aglycone K252c, in which the lactam ring was replaced by a pyrazole moiety, were synthesized. In this series, one or the other nitrogen atoms of the indolocarbazole scaffold was substituted by aminoalkyl chains, aiming at improving protein kinase inhibition as well as cellular potency toward acute myeloid leukemia (AML) cell lines. Compound 19a, substituted at the N12-position by a 3-(methylamino)propyl group, showed high cellular activity in the low micromolar range toward three AML cell lines (MOLM-13, OCI-AML3 and MV4-11) with selectivity over non-cancerous cells (NRK, H9c2). 19a is also a highly potent inhibitor of the three Pim kinase isoforms, Pim-3 being the most inhibited with an IC50 value in the nanomolar range. A selectivity screening toward a panel of 50 protein kinases showed that 19a also potently inhibited PRK2 and to a lower extent AMPK, MARK3, GSK3ß and JAK3. Our results enhance the understanding of the structural characteristics of indolopyrazolocarbazoles essential for potent protein kinase inhibition with therapeutic potential against AML.

Synthesis of diversely substituted pyridin-2(1H)-ones and in vivo evaluation of their anti-allodynic effect on cutaneous inflammatory mechanical allodynia.

A series of 3,5-disubtituted pyridin-2(1H)-ones was synthesized. As part of a structure-activity relationship study performed in this series, structural modifications were based on 3-(indol-4-yl)-5-(pyridin-4-ylamino)pyridin-2(1H)-one B, which exhibited a potent anti-allodynic effect in a rat model of inflammatory pain. In this study, new compounds were assessed for their ability to inhibit cutaneous mechanical allodynia in rats by using the capsaicin pain model. Compound 36, a 2-methoxypyridine derivative, yielded the most promising outcome, demonstrating an enhanced analgesic effect.

The Nitro Group Reshapes the Effects of Pyrido[3,4-g]quinazoline Derivatives on DYRK/CLK Activity and RNA Splicing in Glioblastoma Cells.

Serine-threonine protein kinases of the DYRK and CLK families regulate a variety of vital cellular functions. In particular, these enzymes phosphorylate proteins involved in pre-mRNA splicing. Targeting splicing with pharmacological DYRK/CLK inhibitors emerged as a promising anticancer strategy. Investigation of the pyrido[3,4-g]quinazoline scaffold led to the discovery of DYRK/CLK binders with differential potency against individual enzyme isoforms. Exploring the structure-activity relationship within this chemotype, we demonstrated that two structurally close compounds, pyrido[3,4-g]quinazoline-2,10-diamine 1 and 10-nitro pyrido[3,4-g]quinazoline-2-amine 2, differentially inhibited DYRK1-4 and CLK1-3 protein kinases in vitro. Unlike compound 1, compound 2 efficiently inhibited DYRK3 and CLK4 isoenzymes at nanomolar concentrations. Quantum chemical calculations, docking and molecular dynamic simulations of complexes of 1 and 2 with DYRK3 and CLK4 identified a dramatic difference in electron donor-acceptor properties critical for preferential interaction of 2 with these targets. Subsequent transcriptome and proteome analyses of patient-derived glioblastoma (GBM) neurospheres treated with 2 revealed that this compound impaired CLK4 interactions with spliceosomal proteins, thereby altering RNA splicing. Importantly, 2 affected the genes that perform critical functions for cancer cells including DNA damage response, p53 signaling and transcription. Altogether, these results provide a mechanistic basis for the therapeutic efficacy of 2 previously demonstrated in in vivo GBM models.

Synthesis and biological evaluation of Haspin inhibitors: Kinase inhibitory potency and cellular activity.

Haspin (haploid germ cell-specific nuclear protein kinase) offers a potential target for the development of new anticancer drugs. Thus, the identification of new inhibitors targeting this protein kinase is of high interest. However, Haspin inhibitors developed to date show a poor selectivity profile over other protein kinases of the human kinome. Here, we identified a new pyridoquinazoline based inhibitor (4), with excellent inhibitory activity and selectivity for Haspin (IC50 of 50 nM). We describe the structure-activity relationship study including the evaluation of this inhibitor on a large panel of 486 kinases as well as on immortalized or cancer cell lines. In addition, we determined the binding mode of analog 2a in complex with Haspin using X-ray crystallography.

Alternative RNA splicing modulates ribosomal composition and determines the spatial phenotype of glioblastoma cells.

Glioblastoma (GBM) is characterized by exceptionally high intratumoral heterogeneity. However, the molecular mechanisms underlying the origin of different GBM cell populations remain unclear. Here, we found that the compositions of ribosomes of GBM cells in the tumour core and edge differ due to alternative RNA splicing. The acidic pH in the core switches before messenger RNA splicing of the ribosomal gene RPL22L1 towards the RPL22L1b isoform. This allows cells to survive acidosis, increases stemness and correlates with worse patient outcome. Mechanistically, RPL22L1b promotes RNA splicing by interacting with lncMALAT1 in the nucleus and inducing its degradation. Contrarily, in the tumour edge region, RPL22L1a interacts with ribosomes in the cytoplasm and upregulates the translation of multiple messenger RNAs including TP53. We found that the RPL22L1 isoform switch is regulated by SRSF4 and identified a compound that inhibits this process and decreases tumour growth. These findings demonstrate how distinct GBM cell populations arise during tumour growth. Targeting this mechanism may decrease GBM heterogeneity and facilitate therapy.

Improved potency of pyridin-2(1H)one derivatives for the treatment of mechanical allodynia.

Mechanical allodynia, a painful sensation caused by innocuous touch, is a major chronic pain symptom, which often remains without an effective treatment. There is thus a need for new anti-allodynic treatments based on new drug classes. We recently synthetized new 3,5-disubstituted pyridin-2(1H)-one derivatives. By substituting the pyridinone at the 3-position by various aryl/heteroaryl moieties and at the 5-position by a phenylamino group, we discovered that some derivatives exhibited a strong anti-allodynic potency in rats. Here, we report that varying the substitution of the pyridinone 5-position, the 3-position being substituted by an indol-4-yl moiety, further improves such anti-allodynic potency. Compared with 2, one of the two most active compounds of the first series, eleven out of nineteen newly synthetized compounds showed higher anti-allodynic potency, with two of them completely preventing mechanical allodynia. In the first series, hit compounds 1 and 2 appeared to be inhibitors of p38α MAPK, a protein kinase known to underlie pain hypersensitivity in animal models. Depending on the substitution at the 5-position, some newly synthetized compounds were also stronger p38α MAPK inhibitors. Surprisingly, though, anti-allodynic effects and p38α MAPK inhibitory potencies were not correlated, suggesting that other biological target(s) is/are involved in the analgesic activity in this series. Altogether, these results confirm that 3,5-disubstituted pyridine-2(1H)-one derivatives are of high interest for the development of new treatment of mechanical allodynia.

Synthesis of N-aryl-3-(indol-3-yl)propanamides and their immunosuppressive activities.

N-aryl-3-(indol-3-yl)propanamides were synthesized and their immunosuppressive activities were evaluated. This study highlighted the promising potency of 3-[1-(4-chlorobenzyl)-1H-indol-3-yl]-N-(4-nitrophenyl)propanamide 15 which exhibited a significant inhibitory activity on murine splenocytes proliferation assay in vitro and on mice delayed-type hypersensitivity (DTH) assay in vivo.

Pyridin-2(1H)one derivatives: A possible new class of therapeutics for mechanical allodynia.

Mechanical Allodynia (MA), a frequent chronic pain symptom caused by innocuous stimuli, constitutes an unmet medical need, as treatments using analgesics available today are not always effective and can be associated with important side-effects. A series of 3,5-disubstituted pyridin-2(1H)-ones was designed, synthesized and evaluated in vivo toward a rat model of inflammatory MA. We found that the series rapidly and strongly prevented the development of MA. 3-(2-Bromophenyl)-5-(phenylamino)pyridin-2(1H)-one 69, the most active compound of the series, was also able to quickly reverse neuropathic MA in rats. Next, when 69 was evaluated toward a panel of 50 protein kinases (PK) in order to identify its potential biological target(s), we found that 69 is a p38α MAPK inhibitor, a PK known to contribute to pain hypersensitivity in animal models. 3,5-Disubstituted pyridin-2(1H)-ones thus could represent a novel class of analgesic for the treatment of MA.

Design of new antifungal agents: synthesis and evaluation of 1-[(1H-indol-5-ylmethyl)amino]-2-phenyl-3-(1H-1,2,4-triazol-1-yl)propan-2-ols.

We previously reported on the design and synthesis of 1-[((hetero)aryl- or piperidinylmethyl)amino]-2-phenyl-3-(1H-1,2,4-triazol-1-yl)propan-2-ols showing various degrees of antifungal activity against Candida albicans and Aspergillus fumigatus strains. Now we have identified a series of 1-[(1H-indol-5-ylmethyl)amino] derivatives which exhibited potent MICs (<65 ng mL(-1)) against C. albicans strain. The synthesis and SAR behind the indole scaffold will be discussed.

Synthesis and structure-activity relationships of 2-phenyl-1-[(pyridinyl- and piperidinylmethyl)amino]-3-(1H-1,2,4-triazol-1-yl)propan-2-ols as antifungal agents.

Continuous efforts on the synthesis and structure-activity relationships (SARs) studies of modified 1-benzylamino-2-phenyl-3-(1H-1,2,4-triazol-1-yl)propan-2-ols as antifungal agents, allowed identification of new 1-[(pyridinyl- and piperidinylmethyl)amino] derivatives with MIC(80) values ranging from 1410.0 to 23.0ngmL(-1) on Candidaalbicans. These results confirmed both the importance of pi-pi stacking and hydrogen bonding interactions in the active site of CYP51-C. albicans.