Discovery of new azaindole-based PI3Kα inhibitors: Apoptotic and antiangiogenic effect on cancer cells

Synthesis and Biological Evaluation of Chalconesulfonamides: En Route to Proapoptotic Agents with Antiestrogenic Potency

Breast and other estrogen receptor α-positive cancers tend to develop resistance to existing drugs. Chalcone derivatives possess anticancer activity based on their ability to form covalent bonds with targets acting as Michael acceptors. This study aimed to evaluate the anticancer properties of a series of chalcones (7a-l) with a sulfonamide group attached to the vinyl ketone moiety. Chalconesulfonamides showed a potent antiproliferative effect at low micromolar concentrations against several cancer cell lines, including ERα-positive 4-hydroxytamoxifen-resistant MCF7/HT2. Immunoblotting of samples treated with the lead compound 7e revealed its potent antiestrogenic activity (ERα/GREB1 axis) and induction of PARP cleavage (an apoptosis marker) in breast cancer cells. The obtained compounds represent a promising basis for further development of targeted drugs blocking hormone pathways in cancer cells.

An insight into the structure-activity relationship studies of anticancer medicinal attributes of 7-azaindole derivatives: a review

In the current portfolio, there is a lot of interest in the 7-azaindole building block for drug discovery. The creation of synthetic, sophisticated methods for the modification of 7-azaindoles is a promising area of research. This review covers the structure-activity relationship of 7-azaindole analogs, which have been shown to be effective anticancer agents in the literature of the past two decades. Positions 1, 3 and 5 of the 7-azaindole ring are the most active sites. Disubstitution is used for the synthesis of a new analog of the 7-azaindole moiety. All positions are used to create novel molecules that are effective anticancer agents. The alkyl, aryl carboxamide group and heterocyclic ring are the most successful types of substitution.

The importance of indole and azaindole scaffold in the development of antitumor agents

With some indoles and azaindoles being successfully developed as anticancer drugs, the design and synthesis of indole and azaindole derivatives with remarkable antitumor activity has received increasing attention and significant progress has been made. This paper reviews the recent progress in the study of tumorigenesis, mechanism of actions and structure activity relationships about anticancer indole and azindole derivatives. Combining structure activity relationships and molecular targets-related knowledge, this review will help researchers design more effective, safe and cost-effective anticancer indoles and azindoles agents.

Novel meriolin derivatives as rapid apoptosis inducers

3-(Hetero)aryl substituted 7-azaindoles possessing multikinase inhibitor activity are readily accessed in a one-pot Masuda borylation-Suzuki coupling sequence. Several promising derivatives were identified as apoptosis inducers and, emphasizing the multikinase inhibition potential, as sphingosine kinase 2 inhibitors. Our measurements provide additional insights into the structure-activity relationship of meriolin derivatives, suggesting derivatives bearing a pyridine moiety with amino groups in 2-position as most active anticancer compounds and thus as highly promising candidates for future in vivo studies.

Synthesis of 2-BMIDA 6,5-bicyclic heterocycles by Cu(i)/Pd(0)/Cu(ii) cascade catalysis of 2-iodoaniline/phenols

A one-pot cascade reaction for the synthesis of 2-BMIDA 6,5-bicyclic heterocycles has been developed using Cu(i)/Pd(0)/Cu(ii) catalysis. 2-Iodoanilines and phenols undergo a Cu(i)/Pd(0)-catalyzed Sonogashira reaction with ethynyl BMIDA followed by in situ Cu(ii)-catalyzed 5-endo-dig cyclization to generate heterocyclic scaffolds with a BMIDA functional group in the 2-position. The method provides efficient access to borylated indoles, benzofurans, and aza-derivatives, which can be difficult to access through alternative methods.

Scope and limitations of a DMF bio-alternative within Sonogashira cross-coupling and Cacchi-type annulation

Pd-catalysed C-C bond formation is an essential tool within the pharmaceutical and agrochemical industries. Many of these reactions rely heavily on polar aprotic solvents; however, despite their utility, these solvents are incompatible with the drive towards more sustainable chemical synthesis. Herein, we describe the scope and limitations of an alternative to DMF derived from renewable sources (Cyrene^TM) in Sonogashira cross-coupling and Cacchi-type annulations.

Design strategies, structure activity relationship and mechanistic insights for purines as kinase inhibitors

Kinases control a diverse set of cellular processes comprising of reversible phosphorylation of proteins. Protein kinases play a pivotal role in human tumor cell proliferation, migration and survival of neoplasia. In the recent past, purine based molecules have emerged as significantly potent kinase inhibitors. In view of their promising potential for the inhibition of kinases, this review article focuses on purines which have progressed as kinase inhibitors during the last five years. A detailed account of the design strategies employed for the synthesis of purine analogs exerting inhibitory effects on diverse kinases has been presented. Apart from presenting the design strategies, the article also highlights the structure activity relationship along with mechanistic insights revealed during the biological evaluation of the purine analogs for kinase inhibition. The interactions with the amino acid residues responsible for kinase inhibitory potential of purine based molecules have also been discussed. In this assemblage, purine based protein kinase inhibitors patented in the past have also been summarized in the tabular form. This compilation will be of great interest for the researchers working in the area of protein kinase inhibitors.

PI3K/Akt/mTOR and Ras/Raf/MEK/ERK signaling pathways inhibitors as anticancer agents: Structural and pharmacological perspectives

The protein kinases regulate cellular functions such as transcription, translation, proliferation, growth and survival by the process of phosphorylation. Over activation of signaling pathways play a major role in oncogenesis. The PI3K signaling pathway is dysregulated almost in all cancers due to the amplification, genetic mutation of PI3K gene and the components of the PI3K pathway themselves. Stimulation of the PI3K/Akt/mTOR and Ras/Raf/MEK/ERK pathways enhances growth, survival, and metabolism of cancer cells. Recently, the PI3K/Akt/mTOR and Ras/Raf/MEK/ERK signaling pathways have been identified as promising therapeutic targets for cancer therapy. The kinase inhibitors with enhanced specificity and improved pharmacokinetics have been considered for design and development of anticancer agents. This review focuses primarily on the Ras/Raf/MEK/ERK and PI3K/Akt/mTOR signaling pathways as therapeutic targets of anticancer drugs, their specific and dual inhibitors, structure activity relationships (SARs) and inhibitors under clinical trials.

Structure-based de novo design and identification of D816V mutant-selective c-KIT inhibitors

To identify potent and selective inhibitors of D816V, the most common gain-of-function c-KIT mutant, we carried out structure-based de novo design using 7-azaindole as the core and the scoring function improved by implementing an accurate solvation free energy term. This approach led to the identification of new c-KIT inhibitors specific for the D816V mutant. The 3-(3,4-dimethoxyphenyl)-7-azaindole scaffold was optimized and represents a lead structure for the design of the potent and specific inhibitors of the D816V mutant. The results of molecular dynamics simulations indicate that hydrogen bonding interactions between the 7-azadindole moiety and the backbone groups of Cys673 are the most significant determinant for the potency and selectivity of c-KIT inhibitors.

Rh(iii)-catalyzed 7-azaindole synthesis via C–H activation/annulative coupling of aminopyridines with alkynes

An efficient Rh(iii)-catalyzed 7-azaindole synthesis was developed via C–H activation/annulative coupling of aminopyridines with alkynes.

The azaindole framework in the design of kinase inhibitors

This review article illustrates the growing use of azaindole derivatives as kinase inhibitors and their contribution to drug discovery and innovation. The different protein kinases which have served as targets and the known molecules which have emerged from medicinal chemistry and Fragment-Based Drug Discovery (FBDD) programs are presented. The various synthetic routes used to access these compounds and the chemical pathways leading to their synthesis are also discussed. An analysis of their mode of binding based on X-ray crystallography data gives structural insights for the design of more potent and selective inhibitors.

Azaindolylsulfonamides, with a more selective inhibitory effect on histone deacetylase 6 activity, exhibit antitumor activity in colorectal cancer HCT116 cells

A series of indolylsulfonylcinnamic hydroxamates has been synthesized. Compound 12, (E)-3-(3-((1H-pyrrolo[2,3-b]pyridin-1-yl)sulfonyl)phenyl)-N-hydroxyacrylamide, which has a 7-azaindole core cap, was shown to have antiproliferative activity against KB, H460, PC3, HSC-3, HONE-1, A549, MCF-7, TSGH, MKN45, HT29, and HCT116 human cancer cell lines. Pharmacological studies indicated that 12 functions as a potent HDAC inhibitor with an IC50 value of 0.1 μM. It is highly selective for histone deacetylase 6 (HDAC6) and is 60-fold more active than against HDAC1 and 223-fold more active than against HDAC2. It has a good pharmacokinetic profile with oral bioavailability of 33%. In in vivo efficacy evaluations in colorectal HCT116 xenografts, compound 12 suppresses tumor growth more effectively than SAHA (1, N-hydroxy-N'-phenyloctanediamide) and is therefore seen as a suitable candidate for further investigation.

Development of DANDYs, new 3,5-diaryl-7-azaindoles demonstrating potent DYRK1A kinase inhibitory activity

A series of 3,5-diaryl-1H-pyrrolo[2,3-b]pyridines were synthesized and evaluated for inhibition of DYRKIA kinase in vitro. Derivatives having hydroxy groups on the aryl moieties (2c, 2j-l) demonstrated high inhibitory potencies with Kis in the low nanomolar range. Their methoxy analogues were up to 100 times less active. Docking studies at the ATP binding site suggested that these compounds bind tightly to this site via a network of multiple H-bonds with the peptide backbone. None of the active compounds were cytotoxic to KB cells at 10(-6) M. Kinase profiling revealed that compound 2j showed 2-fold selectivity for DYRK1A with respect to DYRK2 and DYRK3.

New steroidal 7-azaindole platinum(II) antitumor complexes

Two new steroidal 7-azaindole-based N-donor ligands 17-α-[7-azaindole-5-ethynyl]-17-β-testosterone (ET-Haza) (1) and 17-α-[7-azaindole-5-ethynyl]-19-nortestosterone (LEV-Haza) (2), and two new DNA damaging warheads with an enhanced lipophilicity [Pt(dmba)Cl(L)] (dmba=N,N-dimethylbenzylamine-κN,κC; L=ET-Haza (3) and LEV-Haza (4)) have been prepared and characterized. Values of IC50 were calculated for complexes 3 and 4 against a panel of human tumor cell lines representative of ovarian (A2780 and A2780cis) and breast cancers (T47D). At 48 h of incubation time 3 and 4 showed very low resistance factors (RF of 1) against an A2780 cell line which has acquired resistance to cisplatin, IC50 values of the new complexes towards normal human LLC-PK1 renal cells at 48 h being about double than that of cisplatin. 3 and 4 are able to react with 9-ethylguanine (9-EtG) yielding the corresponding monoadduct [Pt(dmba)(L)(9-EtG)](+) derivatives as followed by ESI-MS. Compound 3 interacts mainly with double-stranded (DS) oligonucleotides as shown by analysis with ESI-TOF-MS, being also able to displace ethidium bromide (EB) from DNA, as observed by an electrophoretic mobility study. 3 and 4 are good cathepsin B inhibitors. Theoretical calculations at the COSMO(CHCl3)/B3LYP-D/def2-TZVPPecp//B3LYP-D/def2-TZVPecp level and energy evaluations at the COSMO(CHCl3)/PWPB95-D3/def2-TZVPPecp level of theory on compound 4 and model systems have been done.

A novel PI3K inhibitor alleviates fibrotic responses in fibroblasts derived from Peyronie's plaques

Peyronie's disease (PD) is fibrosis localized in the tunica albuginea that is characterized by penile deformity and curvature. The pathogenesis of this disease remains unclear even though transforming growth factor-β (TGF-β)/smad signalling has been reported to be associated with PD. Recent studies have shown that phosphoinositide 3-kinase (PI3K)/Akt signalling regulates fibrotic responses including collagen synthesis and cell proliferation. Thus, we synthesized HS-173, a novel PI3K inhibitor, and determined whether this compound has anti-fibrotic effects on PD-derived primary fibroblasts. In this study, we found that HS-173 inhibited the growth of fibroblasts in a dose-dependent manner and induced apoptosis. In addition, HS-173 reduced the expression of α-smooth muscle actin (α-SMA), vimentin, PAI-1, fibronectin, collagen type I, collagen IV and TGF-β-activated smad2/3 in PD-derived primary fibroblasts. HS-173 blocked the PI3K/Akt signalling pathway by decreasing the activation of Akt, mTOR and P70S6K. Our results showed that HS-173 suppressed fibrotic responses such as cell proliferation and collagen synthesis by blocking PI3K/Akt signalling in PD-derived primary fibroblasts. Our findings provide molecular insights into the potential therapeutic action of HS-173 through targeting the PI3K/Akt pathway in PD-derived fibroblasts and demonstrated that HS-173 could be used as a pharmacological agent for treating other fibrotic diseases.

HS-116, a novel phosphatidylinositol 3-kinase inhibitor induces apoptosis and suppresses angiogenesis of hepatocellular carcinoma through inhibition of the PI3K/AKT/mTOR pathway

The phosphatidylinositol 3-kinase (PI3K) pathway plays a central role in cell proliferation and survival of human cancers. As PI3K is active in many cancer patients, resulting in cancer development and progression, we developed an azaindole derivative, HS-116 as a novel PI3K inhibitor. This study aimed to clarify the anticancer effect of HS-116 in human hepatocellular carcinoma (HCC). To identify the effect of HS-116 on HCC cells, a PI3K assay, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, flow cytometry, and Western blotting were conducted. IC(50) of HS-116 for PI3Kα was 31nM, and it effectively suppressed the phosphorylation of PI3K downstream factors such as AKT, mTOR, p70S6K, and 4EBP1. Also, HS-116 induced apoptosis by increasing the proportion of sub-G1 apoptotic cells from 1.8% to 35% and increasing the expressions of Bax, cleaved-caspase-3, and cleaved-PARP as well as decreasing the expression of Bcl-2. In addition, chromatin condensation and apoptotic bodies were detected in HS-116-treated HCC cells. Furthermore, HS-116 decreased protein expression of hypoxia-inducible factor-1α (HIF-1α) and vascular endothelial growth factor (VEGF), and inhibited the tube formation and migration of human umbilical vein endothelial cells (HUVECs). In vivo, the ability of mice to vascularize subcutaneously implanted Matrigel plugs was diminished when the mice were treated with HS-116. These results show that HS-116 inhibits the PI3K/AKT/mTOR pathway via apoptosis and anti-angiogenesis in HCC cells. We suggest that HS-116 may be an effective novel therapeutic candidate against HCC.