Microwave-assisted efficient synthesis of pyrazole-fibrate derivatives as stimulators of glucose uptake in skeletal muscle cells.

The design and synthesis of a series of pyrazolo[3,4-d]pyrimidinones containing fibrate side chains have been accomplished by utilizing the concept of molecular hybridization. All the synthesized compounds were evaluated for the glucose uptake stimulatory effect in L6 rat skeletal muscle cells. Four compounds (3f, 3g, 3j and 3q) were found to show significant stimulation of glucose uptake. Further these four compounds have been examined for their Glut4 translocation stimulatory effect in L6-Glut4myc myotubes. Compound 3q was found to exert maximum increase in GLUT4myc translocation.

Synthesis, biological evaluation and molecular dynamic simulations of novel Benzofuran-tetrazole derivatives as potential agents against Alzheimer's disease.

A series of novel Benzofuran-tetrazole derivatives were successfully synthesised by integrating multicomponent Ugi-azide reaction with the molecular hybridization approach. Interestingly, a number of synthesized derivatives (5c, 5d, 5i, 5l, 5q and 5s) exhibited significant reduction of aggregation of "human" amyloid beta peptide, expressing on transgenic Caenorhabditis elegans (C. elegans) strain CL4176. Further, in silico docking results have evidenced the exquisite interaction of active compounds with the help of TcAChE-E2020 complex. These findings underscore the potential of these hybrids as lead molecules against Alzheimers's disease.

Benzofuran-pyran hybrids: A new class of potential bone anabolic agents.

Benzofuran moiety is an important pharmacophore showing positive effects on bone health. In the present study, sixteen benzofuran-pyran hybrids were synthesized and were evaluated for their osteogenic effects on primary osteoblast cells isolated from calvaria. Compounds 22 and 24 were found potent in stimulating osteoblast differentiation as assessed by the alkaline phosphatase activity. These compounds were also found to be nontoxic to osteoblast cells as compared to the control cells in MTT assay. Further, Alizarin Red-S staining for visualization of calcium nodules demonstrated compounds 22 and 34 as active in enhancing mineralization in osteoblast cells. Additionally, transcriptional analysis of these compounds on osteoblast cells revealed that compound 22 up-regulated the expression of osteogenic genes RUNX2, BMP-2, COL-1, thus substantiating that compound 22 having two geminal methyl groups in its R3 position is a potent osteogenic agent. Additionally, compound 22 enhanced the ability of bone marrow stromal cells to differentiate towards osteoblast lineage and therefore can be further studied in vivo in bone loss model.

In-house chemical library repurposing: A case example for Pseudomonas aeruginosa antibiofilm activity and quorum sensing inhibition.

Hit, Lead & Candidate Discovery Drug repurposing has become a recent trend in drug development programs, where previously developed drugs are explored for hit and redeveloped into potential therapeutic agents for new diseases. Globally, in any drug development program, a series of molecules are synthesized and evaluated for the hypothesized activity. Hits are developed into lead molecules or drugs, whereas the negative ones are shelved in the lab with no immediate use. We in this project took the previously sidelined small chemical molecules to the next level of utility, where previously developed in-house small molecules library are tested for the unexplored biological relevant activity. As biofilm formation and quorum sensing play a vital role in bacterial pathogenesis, we believe that they could be one of the most effective targets for antimicrobial agents. In this study, we report the evaluation of 50 different compounds for anti-biofilm and anti-quorum sensing activity against Pseudomonas aeruginosa. Out of the screened compounds, three hydrazine-carboxamide hybrid derivatives showed promising anti-biofilm property and inhibition of pyocyanin production without any direct antimicrobial activity and cytotoxicity issues. Hydrazine-carboxamide hybrids can be a new class and promising leads for further anti-biofilm and anti-virulence development against microbial infections.

Benzofuran-dihydropyridine hybrids: A new class of potential bone anabolic agents.

A series of novel benzofuran-dihydropyridine hybrids were designed by molecular hybridization approach and evaluated for bone anabolic activities. Among the screened library, ethyl 4-(7-(sec-butyl)-2-(4-methylbenzoyl)benzofuran-5-yl)-2-methyl-5-oxo-1,4,5,6,7,8-hexahydroquinoline-3-carboxylate (compound 21) significantly enhanced the ALP production and mineralized nodule formation, which are primary requisites in the process of in vitro osteogenesis. Oral administration of compound 21 at 10 mg.kg-1 day-1 for two weeks led to restoration of trabecular bone microarchitecture in drill hole fracture model by significantly increasing BV/TV and Tb.N. Furthermore, histological and molecular studies showed compound 21 triggering the new bone regeneration in a drill hole defect site by increasing BMP expression. Furthermore, molecular modeling studies were performed to gain insight into the binding approach, which revealed that both benzofuran and dihydropyridine moieties are essential to show similar binding interactions to fit into the active site of BMP2 receptor, an important target of the osteogenic agents. Our results suggest that compound 21 stimulates BMP2 synthesis in osteoblast cells that promotes new bone formation (∼40%) at the fracture site which helps in shorten the healing period.

Design and synthesis of new series of coumarin-aminopyran derivatives possessing potential anti-depressant-like activity.

A new series of coumarin based aminopyran derivatives were designed, synthesized and evaluated for their preclinical antidepressant effect on Swiss albino mice. Among the series, compounds 21, 25, 26, 27, 32 and 33 exhibited significant activity profile in forced swimming test (FST). Compound 27 was most efficacious, which at a very low dose of 0.5mg/kg reduced the time of immobility by 86.5% as compared to the standard drug fluoxetine (FXT) which reduced the immobility time by 69.8% at the dose of 20mg/kg, ip. In addition, all active compounds were screened in dose dependent manner (at doses of 0.25, 0.5, 1mg/kg ip) in FST and tail suspension test (TST). Interestingly, all active compounds did not caused any significant alteration of locomotor activity in mice as compared to control, indicating that the hybrids did not produce any motor impairment effects. The results indicate that coumarin-aminopyran derivatives may have potential therapeutic value for the management of mental depression.

Room-temperature chemoselective reduction of nitro groups using non-noble metal nanocatalysts in water.

Purely aqueous-phase chemoselective reduction of a wide range of aromatic and aliphatic nitro substrates has been performed in the presence of inexpensive Ni- and Co-based nanoparticle catalysts using hydrazine hydrate as a reducing agent at room temperature. Along with the observed high conversions and selectivities, the studied nanoparticle catalysts also exhibit a high tolerance to other highly reducible groups present in the nitro substrates. The development of these potential chemoselective reduction catalysts also provides a facile route for the synthesis of other industrially important fine chemicals or biologically important compounds, where other highly reducible groups are present in close proximity to the targeted nitro groups.

Synergy between human DNA ligase I and topoisomerase 1 unveils new therapeutic strategy for the management of colorectal cancer.

DNA topoisomerase 1 (Topo 1) is a pivotal player in various DNA processes, including replication, repair, and transcription. It serves as a target for anticancer drugs like camptothecin and its derivatives (Topotecan and SN-38/Irinotecan). However, the emergence of drug resistance and the associated adverse effects, such as alopecia, anemia, dyspnea, fever, chills, and painful or difficult urination, pose significant challenges in Topo 1-targeted therapy, necessitating urgent attention. Human DNA Ligase 1 (hLig I), recognized primarily for its role in DNA replication and repair of DNA breaks, intriguingly exhibits a DNA relaxation activity akin to Topo 1. This raised the hypothesis that hLig I might compensate for Topo 1 inhibition, contributing to resistance against Topo 1 inhibitors. To explore this hypothesis, we assessed the efficacy of hLig I inhibition alone and in combination with Topo 1 in cancer cells. As anticipated, the overexpression of hLig I was observed after Topo 1 inhibition in colorectal cancer cells, affirming our hypothesis. Previously identified as an inhibitor of hLig I's DNA relaxation activity, compound 27 (C 27), when combined with Topotecan, demonstrated a synergistic antiproliferative effect on colorectal cancer cells. Notably, cells with downregulated hLig I (via siRNA, inhibitors, or genetic manipulation) exhibited significantly heightened sensitivity to Topotecan. This observation strongly supports the concept that hLig I contribute to resistance against clinically relevant Topo 1 inhibitors in colorectal cancers. In conclusion, our findings offer evidence for the synergistic impact of combining hLig I inhibitors with Topotecan in the treatment of colorectal cancers, providing a promising strategy to overcome resistance to Topo 1 inhibitors.Communicated by Ramaswamy H. Sarma.

Design, synthesis and biological evaluation of new quinazolinone-benzopyran-indole hybrid compounds promoting osteogenesis through BMP2 upregulation.

In search of novel osteogenic entities, a series of twenty-seven quinazolinone-benzopyran-indole hybrids were designed and synthesized using molecular hybridization approach. All the compounds were scrutinized for their osteogenic potential, primarily based on alkaline phosphatase assay as one of the major anabolic markers. From the primary screening, four osteogenic compounds were sorted from the series and were found nontoxic to the osteoblasts. Further, increased osteoblast differentiation and osteogenic mRNA upregulations suggest compound 47 as the most potent osteoanabolic agent. Immunoblot and ELISA analysis demonstrated that compound 47 promotes osteogenesis via RUNX2 and BMP2 mediated non-canonical p38 pathway. In vivo studies in BALB/c mice inferred that compound 47 stimulates bone anabolism as evident from histological and gene expression studies at 5 mg. kg-1. day-1 dose. Furthermore, structural activity relationship (SAR) and pharmacokinetic studies suggest compound 47 as a BMP2 upregulator and a potential bone anabolic lead for combating future bone metabolic disorders.

Targeting 11q23 positive acute leukemia cells with high molecular weight-melanoma associated antigen-specific monoclonal antibodies.

BACKGROUND: Acute leukemia with 11q23 aberrations is associated with a poor outcome with therapy. The lack of efficacy of conventional therapy has stimulated interest in developing novel strategies. Recent studies have shown that 11q23-positive acute leukemia cells express the high molecular weight-melanoma associated antigen (HMW-MAA). This tumor antigen represents a useful target to control growth of human melanoma tumors in patients and in severe combined immunodeficient (SCID) mice, utilizing antibody-based immunotherapy. This effect appears to be mediated by inhibition of the HMW-MAA function such as triggering of the focal adhesion kinase/proline-rich tyrosine kinase 2 (Pyk2) pathways. Therefore, in this study we tested whether HMW-MAA-specific monoclonal antibodies (mAb) could inhibit growth of 11q23-positive leukemia cells in SCID mice. METHODS: HMW-MAA-specific mAb were tested for their ability to inhibit the in vitro proliferation of an 11q23-positive acute myeloid leukemia (AML) cell line and blasts from four patients with 11q23 aberrations and their in vivo growth in subcutaneous and disseminated xenograft models. RESULTS: The HMW-MAA-specific mAb did not affect in vitro proliferation although they down-regulated phosphorylated (P) Pyk2 expression. Furthermore, the mAb enhanced the in vitro anti-proliferative effect of cytarabine. In vivo the mAb inhibited the growth of leukemic cells in a dose-dependent fashion. However, the difference did not reach statistical significance. No effect was detected on P-Pyk2 expression. Furthermore, HMW-MAA-specific mAb in combination with cytarabine did not improve tumor inhibition. Lastly, the combination of two mAb which recognize distinct HMW-MAA determinants had no detectable effect on survival in a disseminated xenograft model. CONCLUSIONS: HMW-MAA-specific mAb down-regulated P-Pyk2 expression and enhanced the anti-proliferative effect of cytarabine in vitro, but had no detectable effect on survival or growth of leukemia cells in vivo. Whether the HMW-MAA-specific mAb can be used as carriers of toxins or chemotherapeutic agents against 11q23-acute leukemia remains to be determined.

Synthesis, Biological Evaluation, Structure-Activity Relationship, and Mechanism of Action Studies of Quinoline-Metronidazole Derivatives Against Experimental Visceral Leishmaniasis.

In our efforts to identify novel chemical scaffolds for the development of antileishmanial agents, a series of quinoline-metronidazole hybrid compounds was synthesized and tested against the murine model of visceral leishmaniasis. Among all synthesized derivatives, 15b and 15i showed significant antileishmanial efficacy against both extracellular promastigote (IC50 9.54 and 5.42 µM, respectively) and intracellular amastigote (IC50 9.81 and 3.75 µM, respectively) forms of Leishmania donovani with negligible cytotoxicity toward the host (J774 macrophages, Vero cells). However, compound 15i effectively inhibited the parasite burden in the liver and spleen (>80%) of infected BALB/c mice. Mechanistic studies revealed that 15i triggers oxidative stress which induces bioenergetic collapse and apoptosis of the parasite by decreasing ATP production and mitochondrial membrane potential. Structure-activity analyses and pharmacokinetic studies suggest 15i as a promising antileishmanial lead and emphasize the importance of quinoline-metronidazole series as a suitable platform for the future development of antileishmanial agents.

Epigenetic regulation of signal transducer and activator of transcription 3 in acute myeloid leukemia.

We have demonstrated that constitutive signal transducer and activator of transcription (STAT) 3 activity, observed in approximately 50% of acute myeloid leukemia (AML) cases, is associated with adverse treatment outcome. Constitutive STAT3 activation may result from the expression of oncogenic protein tyrosine kinases or from autocrine stimulation by hematopoietic growth factors. These causes are generally neither necessary nor sufficient for leukemogenesis; additional transforming events or growth stimulatory processes are needed. Here we review the literature addressing epigenetic regulation as a mechanism controlling STAT3 signaling in AML. A better understanding of mechanisms of dysregulation of STAT signaling pathways may serve as a basis for designing novel therapeutic strategies that target these pathways in leukemia cells.

Synthesis and bio-evaluation of indole-chalcone based benzopyrans as promising antiligase and antiproliferative agents.

DNA replication and repair are complex processes accomplished by the concerted action of a network of enzymes and proteins. DNA ligases play a crucial role in these processes by catalyzing the nick joining between DNA strands. As compared to normal cells, elevated levels of human DNA ligase I (hLigI) is reported in some cancers. We studied the inhibition of hLigI mediated DNA nick sealing activity followed by the antiproliferative activity of novel indole-chalcone based benzopyran compounds on cancer cells. One molecule called compound 27 showed a notable preference for inhibition of hLigI as compared to other ligases and showed enhanced cytotoxicity against colon cancer (DLD-1) cells as compared to normal cells. Mechanistic studies showed that compound 27 directly interacts with hLigI in a competitive manner and did not interact with the DNA substrate during ligation. This novel and potent hLigI inhibitor showed significant inhibition of both monolayer culture as well as 3D culture of DLD-1 cells that mimic solid tumor. It also affected the migration of DLD-1 cells indicating the potential anti-metastatic activity. This novel hLigI inhibitor could therefore serve as a promising lead for anticancer drug development.

Synthesis and evaluation of novel triazolyl quinoline derivatives as potential antileishmanial agents.

The high potential of quinoline containing natural products and their derivatives in medicinal chemistry led us to discover novel series of 25 compounds for the development of new antileishmanial agents. A series of triazolyl 2-methyl-4-phenylquinoline-3-carboxylate derivatives has been synthesized via click chemistry inspired molecular hybridization approach and evaluated against Leishmania donovani. Most of the screened derivatives exhibited significant in vitro anti-leishmanial activity against promastigote (IC50 ranging from 2.43 to 45.75 µM) and intracellular amastigotes (IC50 ranging from 7.06 to 34.9 µM) than the control, miltefosine (IC50 = 8.4 µM), with less cytotoxicity in comparison to the standard drugs. Overall results revealed that prototype signify a new structural lead for antileishmanial chemotherapy.

Synthesis and study of benzofuran-pyran analogs as BMP-2 targeted osteogenic agents.

Twenty-four novel benzofuran-pyran derivatives were synthesized and evaluated for their anti-osteoporotic activity in primary cultures of rat calvarial osteoblasts in vitro. Among all the compounds screened for the alkaline phosphatase activity, three compounds 4e, 4j and 4k showed potent activity at picomolar concentrations in osteoblast differentiating stimulation. Additionally, these compounds were found effective in mineralization, assessed by alizarin red-S staining assay. Compounds were again validated through a series of other in vitro experiments. Moreover, molecular dynamics simulations demonstrated that both benzofuran and pyran moieties are requisite to fit into the active site of BMP-2 receptor, a key target of the osteogenic agents. The obtained results strongly convey that compound 4e is a potential bone anabolic agent among synthesized series, which can be further explored as a drug lead for treating osteoporosis.

Discovery of coumarin-dihydroquinazolinone analogs as niacin receptor 1 agonist with in-vivo anti-obesity efficacy.

In this study, we presented rational designing and synthesis of coumarin-dihydroquinazolinone conjugates to evaluate their agonist activity at GPR109a receptor. Among the synthesized small molecule library, compound 10c displayed robust agonist action at GPR109a with EC50 < 11 nM. Homology model of human GPR109a protein was generated to realize the binding interaction of the active molecule with the active site of GPR109a. Further, the efficacy of active compound 10c was supported by in-vivo experiments which showed reduced body weight in diet induced obese mice model. Interestingly, compound 10c reduced leptin in blood plasma and total serum cholesterol. These results suggest that the coumarin-dihydroquinazolinone conjugate is a suitable scaffold to further expand the chemical diversity and make them potential niacin receptor 1 agonist.

TIMP-1 downregulation modulates miR-125a-5p expression and triggers the apoptotic pathway.

Matrix metalloproteinases and their natural inhibitors (TIMPs) are important elements in a wide range of oncology settings. Elevated levels of tissue inhibitor of metalloproteinase-1 (TIMP-1) have often been associated with increased tumorigenesis. This has been demonstrated in a number of clinical and experimental models which include breast, gastric, colorectal and non-small cell lung carcinoma (NSCLC). Our earlier studies have identified increased angiogenic activity and aggressive tumor kinetics in TIMP-1 overexpressing H2009 lung adenocarcinoma cells. TIMP-1 overexpression has also been implicated in antiapoptotic responses, inducing a significant upregulation of Bcl-2. These TIMP-1 functions have been shown to be MMP-independent and provide insight into its pleiotropic activities. The current study examines microRNA (miRNA) interactions with this molecule. We have sought to define the relationship between TIMP-1 and miRNA by knocking down TIMP-1 in high TIMP-1 expressing lung adenocarcinoma cell lines. TIMP-1 knockdown resulted in increased expression of miR-125a-5p with a concomitant increase in apoptosis and attenuation of the tumorigenic features of these cells. We have identified TIMP-1 as a bona fide target of miR-125a-5p, and their interaction resulted in an increase in p53 expression. We further corroborated our in vitro data with patient samples, which exhibited an inverse correlation between TIMP-1 and miR-125a-5p expression. Our study lends support to the notion that elevated TIMP-1 levels, which are frequently associated with poor prognosis, cause aberrant modulation of miRNAs.

TIMP-1 overexpression in lung carcinoma enhances tumor kinetics and angiogenesis in brain metastasis.

Tissue inhibitors of matrix metalloproteinase (TIMP) orchestrate many biologic activities, including inhibition of matrix metalloproteinase activity, activation of pro-matrix metalloproteinases, and regulation of cell proliferation, angiogenesis, and apoptosis induction. Tissue inhibitors of matrix metalloproteinase can play a protective role during tumor invasion and metastasis, but elevated TIMP messenger RNA levels have also been associated with aggressive cancers and poor clinical outcome. We examined the potential roles of TIMP-1 in H2009 lung adenocarcinoma cells and in cells transfected with a human TIMP-1-overexpressing vector (HB-6 and HB-1). Tumors resulting from the implantation of parental cell lines and transfected HB-1 cells into the brains of nude mice had a typical carcinoma profile, but human TIMP-1-overexpressing tumors showed enhanced tumor kinetics and focally more infiltrative features; vessel density assessed with anti-CD31 immunohistochemistry was also greater within HB-1 tumor implants. Similar effects on HB-6 and HB-1 cells versus parental cell lines and empty vector clones were observed in endothelial cell assays. Anchorage-independent growth and invasion through Matrigel were also increased in TIMP-1-overexpressing cells. Together, these results indicate tumor-promoting functions of TIMP-1 through alterations in angiogenesis, increased tumorigenicity, and invasive behavior. Although matrix metalloproteinase inhibition has been the traditionally identified function of TIMP-1, matrix metalloproteinase-independent interactions may contribute to the growth of metastatic carcinomas in the brain.

TIMP-1 Inhibits Apoptosis in Lung Adenocarcinoma Cells via Interaction with Bcl-2.

Tissue inhibitors of metalloproteinases (TIMPs) are multifaceted molecules that exhibit properties beyond their classical proteinase inhibitory function. Although TIMP-1 is a known inhibitor of apoptosis in mammalian cells, the mechanisms by which it exerts its effects are not well-established. Our earlier studies using H2009 lung adenocarcinoma cells, implanted in the CNS, showed that TIMP-1 overexpressing H2009 cells (HB-1), resulted in more aggressive tumor kinetics and increased vasculature. The present study was undertaken to elucidate the role of TIMP-1 in the context of apoptosis, using the same lung cancer cell lines. Overexpressing TIMP-1 in a lung adenocarcinoma cell line H2009 resulted in an approximately 3-fold increased expression of Bcl-2, with a marked reduction in apoptosis upon staurosporine treatment. This was an MMP-independent function as a clone expressing TIMP-1 mutant T2G, lacking MMP inhibition activity, inhibited apoptosis as strongly as TIMP1 overexpressing clones, as determined by inhibition of PARP cleavage. Immunoprecipitation of Bcl-2 from cell lysates also co-immunoprecipitated TIMP-1, indicative of an interaction between these two proteins. This interaction was specific for TIMP-1 as TIMP-2 was not present in the Bcl-2 pull-down. Additionally, we show a co-dependency of TIMP-1 and Bcl-2 RNA and protein levels, such that abrogating Bcl-2 causes a downregulation of TIMP-1 but not TIMP-2. Finally, we demonstrate that TIMP-1 dependent inhibition of apoptosis occurs through p90RSK, with phosphorylation of the pro-apoptotic protein BAD at serine 112, ultimately reducing Bax levels and increasing mitochondrial permeability. Together, these studies define TIMP-1 as an important cancer biomarker and demonstrate the potential TIMP-1 as a crucial therapeutic target.

Comparative study of heart rate responses to laryngoscopic endotracheal intubation and to endotracheal intubation using intubating laryngeal mask airway under general anaesthesia in patients with pure mitral stenosis for closed mitral commissurotomy.

The various drugs and methods studied in an attempt to curb the haemodynamic stress response associated with conventional laryngoscopic endotracheal intubation have not been found to be ompletely satisfactory. The rise in heart rate can be detrimental to patients with mitral stenosis. This study was aimed to compare the heart rate responses to endotracheal intubation using conventional laryngoscope and with the help of intubating laryngeal mask airway (ILMA) in patients with isolated mitral stenosis. Thirty-four adult patients of either sex, aged between 18 and 40 years with isolated mitral stenosis to undergo closed mitral commissurotomy were randomly allocated into two groups : Group A (n=17)- To be intubated using laryngoscopy. Group B (n=17)- To be intubated with the help of ILMA. The heart rate was recorded immediately preinduction, just prior to introducing the intubating device and postintubation every minute up to first 5 minutes. On applying statistical tests, it was found that the median heart rate values in group A at 2, 3, 4 and 5 minutes postintubation were significantly higher than in group B (p<0.05). Although use of both laryngosope and ILMA for endotracheal intubation was associated with rise in heart rate, the rise was less with ILMA compared to laryngoscope. Hence, it can be concluded that use of ILMA may be a preferable device for endotracheal intubation laryngoscopy in patients with isolated mitral stenosis.