Synthesis of some novel androstanes as potential aromatase inhibitors

Novel pyrazole and isoxazole derivatives (6-9) were synthesized as a aromatase inhibitors. Pyrazole was synthesized from hydrazine hydrate and isoxazoles from hydroxylamine hydrochloride under different conditions. Molecular docking studies were carried out for the synthesized compounds. The best score was obtained for the compound (9) followed by compound (6) while compound (8) afforded poorest of the score. Aromatase inhibitory activity for compound (6) having pyrazole ring at 2,3 position showed highest activity followed by nitrile derivative (9). Isomeric forms of isoxazole (7 and 8) showed very poor activity compared to fadrozole and aminoglutethimide. Preliminary kinetic studies have shown that both of the active compounds (6 and 9) are reversible inhibitors of the enzyme.     

Distribution of naphthoquinones, plumbagin, droserone, and 5-O-methyl droserone in chitin-induced and uninduced Nepenthes khasiana: molecular events in prey capture

Prey capture and digestion in Nepenthes spp. through their leaf-evolved biological traps involve a sequence of exciting events. Sugar-rich nectar, aroma chemicals, narcotic alkaloid secretions, slippery wax crystals, and other biochemicals take part in attracting, capturing, and digesting preys in Nepenthes pitchers. Here we report the distribution of three potent naphthoquinones in Nepenthes khasiana and their roles in prey capture. Plumbagin was first detected in N. khasiana, and its content (root: 1.33 ± 0.02%, dry wt.) was the highest found in any natural source. Chitin induction enhanced plumbagin levels in N. khasiana (root: 2.17 ± 0.02%, dry wt.). Potted N. khasiana plants with limited growth of roots and aerial parts, showed higher levels of plumbagin accumulation (root: 1.92 ± 0.02%; root, chitin induction: 3.30 ± 0.21%, dry wt.) compared with field plants. Plumbagin, a known toxin, insect ecdysis inhibitor, and antimicrobial, was also found embedded in the waxy layers at the top prey capture region of N. khasiana pitchers. Chitin induction, mimicking prey capture, produced droserone and 5-O-methyl droserone in N. khasiana pitcher fluid. Both these naphthoquinone derivatives provide antimicrobial protection to the pitcher fluid from visiting preys. A two-way barrier was found between plumbagin and its two derivatives. Plumbagin was never detected in the pitcher fluid whereas both its derivatives were only found in the pitcher fluid on chitin induction or prey capture. The three naphthoquinones, plumbagin, droserone, and 5-O-methyl droserone, act as molecular triggers in prey capture and digestion in the carnivorous plant, N. khasiana.     

MET and PI3K/mTOR as a Potential Combinatorial Therapeutic Target in Malignant Pleural Mesothelioma

Malignant pleural mesothelioma (MPM) is an aggressive disease with a poor prognosis. Studies have shown that both MET and its key downstream intracellular signaling partners, PI3K and mTOR, are overexpressed in MPM. Here we determined the combinatorial therapeutic efficacy of a new generation small molecule inhibitor of MET, ARQ 197, and dual PI3K/mTOR inhibitors NVP-BEZ235 and GDC-0980 in mesothelioma cell and mouse xenograft models. Cell viability results show that mesothelioma cell lines were sensitive to ARQ 197, NVP-BEZ235 and GDC-0980 inhibitors. The combined use of ARQ 197 with either NVP-BEZ235 or GDC-0980, was synergistic (CI<1). Significant delay in wound healing was observed with ARQ 197 (p<0.001) with no added advantage of combining it with either NVP-BEZ235 or GDC-0980. ARQ 197 alone mainly induced apoptosis (20±2.36%) that was preceded by suppression of MAPK activity, while all the three suppressed cell cycle progression. Both GDC-0980 and NVP-BEZ235 strongly inhibited activities of PI3K and mTOR as evidenced from the phosphorylation status of AKT and S6 kinase. The above observation was further substantiated by the finding that a majority of the MPM archival samples tested revealed highly active AKT. While the single use of ARQ 197 and GDC-0980 inhibited significantly the growth of MPM xenografts (p<0.05, p<0.001 respectively) in mice, the combination of the above two drugs was highly synergistic (p<0.001). Our results suggest that the combined use of ARQ 197/NVP-BEZ235 and ARQ 197/GDC-0980 is far more effective than the use of the drugs singly in suppressing MPM tumor growth and motility and therefore merit further translational studies.     

Exome Sequencing Is an Efficient Tool for Variant Late-Infantile Neuronal Ceroid Lipofuscinosis Molecular Diagnosis

The neuronal ceroid-lipofuscinoses (NCL) is a group of neurodegenerative disorders characterized by epilepsy, visual failure, progressive mental and motor deterioration, myoclonus, dementia and reduced life expectancy. Classically, NCL-affected individuals have been classified into six categories, which have been mainly defined regarding the clinical onset of symptoms. However, some patients cannot be easily included in a specific group because of significant variation in the age of onset and disease progression. Molecular genetics has emerged in recent years as a useful tool for enhancing NCL subtype classification. Fourteen NCL genetic forms (CLN1 to CLN14) have been described to date. The variant late-infantile form of the disease has been linked to CLN5, CLN6, CLN7 (MFSD8) and CLN8 mutations. Despite advances in the diagnosis of neurodegenerative disorders mutations in these genes may cause similar phenotypes, which rends difficult accurate candidate gene selection for direct sequencing. Three siblings who were affected by variant late-infantile NCL are reported in the present study. We used whole-exome sequencing, direct sequencing and in silico approaches to identify the molecular basis of the disease. We identified the novel c.1219T>C (p.Trp407Arg) and c.1361T>C (p.Met454Thr) MFSD8 pathogenic mutations. Our results highlighted next generation sequencing as a novel and powerful methodological approach for the rapid determination of the molecular diagnosis of NCL. They also provide information regarding the phenotypic and molecular spectrum of CLN7 disease.     

Synthesis and Biological Evaluation of Novel Multi-target-Directed Benzazepines Against Excitotoxicity

Excitotoxicty, a key pathogenic event is characteristic of the onset and development of neurodegeneration. The glutamatergic neurotransmission mediated through different glutamate receptor subtypes plays a pivotal role in the onset of excitotoxicity. The role of NMDA receptor (NMDAR), a glutamate receptor subtype, has been well established in the excitotoxicity pathogenesis. NMDAR overactivation triggers excessive calcium influx resulting in excitotoxic neuronal cell death. In the present study, a series of benzazepine derivatives, with the core structure of 3-methyltetrahydro-3H-benzazepin-2-one, were synthesised in our laboratory and their NMDAR antagonist activity was determined against NMDA-induced excitotoxicity using SH-SY5Y cells. In order to assess the multi-target-directed potential of the synthesised compounds, Aβ_1–42 aggregation inhibitory activity of the most potent benzazepines was evaluated using thioflavin T (ThT) and Congo red (CR) binding assays as Aβ also imparts toxicity, at least in part, through NMDAR overactivation. Furthermore, neuroprotective, free radical scavenging, anti-oxidant and anti-apoptotic activities of the two potential test compounds (7 and 14) were evaluated using primary rat hippocampal neuronal culture against Aβ_1–42-induced toxicity. Finally, in vivo neuroprotective potential of 7 and 14 was assessed using intracerebroventricular (ICV) rat model of Aβ_1–42-induced toxicity. All of the synthesised benzazepines have shown significant neuroprotection against NMDA-induced excitotoxicity. The most potent compound (14) showed relatively higher affinity for the glycine binding site as compared with the glutamate binding site of NMDAR in the molecular docking studies. 7 and 14 have been shown experimentally to abrogate Aβ_1–42 aggregation efficiently. Additionally, 7 and 14 showed significant neuroprotective, free radical scavenging, anti-oxidant and anti-apoptotic properties in different in vitro and in vivo experimental models. Finally, 7 and 14 attenuated Aβ_1–42-induced tau phosphorylation by abrogating activation of tau kinases, i.e. MAPK and GSK-3β. Thus, the results revealed multi-target-directed potential of some of the synthesised novel benzazepines against excitotoxicity.     

Role of Vanadium (V) in the Differentiation of C3H10t1/2 Cells Towards Osteoblast Lineage: A Comparative Analysis with Other Trace Elements

In recent time, vanadium compounds are being used as antidiabetic drug and in orthopedic implants. However, the exact role of this incorporated vanadium in improving the quality of bone structure and morphology is not known. The impact of vanadium ion was studied and compared to other trace metal ions with respect to the proliferation and osteoblast differentiation of C3H10t1/2 cells. Toxicity profile of these trace metal ions revealed a descending toxicity trend of Fe²⁺ > Zn²⁺ > Cu²⁺ > Co²⁺ > Mn²⁺ > V⁵⁺ > Cr²⁺. The effect of vanadium and other trace metal ions on osteoblast differentiation was evaluated by culturing the cells for 10 days in osteoblastic medium supplemented with different trace ions at concentrations lower than their cytotoxic doses. The results indicated that vanadium has maximum impact on the induction of osteoblast differentiation by upregulating alkaline phosphatase activity and mineralization by up to 145 and 150 %, respectively (p?<?0.05), over control. Cu²⁺ and Zn²⁺ had a mild inhibitory effect, while Mn²⁺, Fe²⁺, and Co²⁺ demonstrated a clear decrease in osteoblast differentiation when compared to the control. The data as presented here demonstrate that orthopedic implants, if supplemented with trace metals like vanadium, may provide a source of better model for bone formation and its turnover.     

Inhibition of farnesyltransferase: a rational approach to treat cancer?

This article presents in brief the development of farnesyltransferase inhibitors (FTIs) and their preclinical and clinical status. In this review the mechanism of action of FTIs is discussed and their selectivity issue towards tumor cells is also addressed. The significant efficacy of FTIs as single or combined agents in preclinical studies stands in contrast with only moderate effects in Clinical Phase II-III studies. This suggests that there is a need to further explore and understand the complex mechanism of action of FTIs and their interaction with cytotoxic agents.