Hanumappa Ananda

Microwave-assisted synthesis, characterization and cytotoxic studies of novel estrogen receptor α ligands towards human breast cancer cells

A new, simple, and microwave-assisted, solution-phase T3P®-DMSO mediated method for the preparation of a novel class of estrogen receptor alpha (ERα) ligands based on the 2-phenylquinoline scaffold was developed. Furthermore, the novel ERα ligands were tested for their bioactivity against ERα-positive and ERα-negative cell lines. The ligand (entry 4), with amine and nitro group substitution at C4 position, displayed significant cytotoxicity against MCF-7 and HepG2 cells with an IC50 value of 6 and 11μM, respectively. On the other hand, ERα-negative cells displayed resistance to quinolines induced cytotoxicity with an IC50 value >100Mm and they does not induce cytotoxicity in normal breast epithelial cells. Molecular docking analyses suggest a consistent binding mode for these ERα ligands in the ligand binding domain of the human ERα and predict the ligands to occupy the hydrophobic cavity in a similar fashion as estradiol or GW2368.

Development of Novel Triazolo-Thiadiazoles from Heterogeneous “Green” Catalysis as Protein Tyrosine Phosphatase 1B Inhibitors

Condensed-bicyclic triazolo-thiadiazoles were synthesized via an efficient “green” catalyst strategy and identified as effective inhibitors of PTP1B in vitro. The lead compound, 6-(2-benzylphenyl)-3-phenyl-[1,2,4]triazolo[3][1,3,4]thiadiazole (BPTT) was most effective against human hepatoma cells, inhibits cell invasion, and decreases neovasculature in HUVEC and also tumor volume in EAT mouse models. This report describes an experimentally unidentified class of condensed-bicyclic triazolo-thiadiazoles targeting PTP1B and its analogs could be the therapeutic drug-seeds.

A novel benzimidazole derivative binds to the DNA minor groove and induces apoptosis in leukemic cells

DNA minor groove binders are an important class of chemotherapeutic agents. These small molecule inhibitors interfere with various cellular processes like DNA replication and transcription. Several benzimidazole derivatives showed affinity towards the DNA minor groove. In this study we show the synthesis and biological studies of a novel benzimidazole derivative (MH1), that inhibits topoisomerase II activity and in vitro transcription. UV-visible and fluorescence spectroscopic methods in conjunction with Hoechst displacement assay demonstrate that MH1 binds to DNA at the minor groove. Cytotoxic studies showed that leukemic cells are more sensitive to MH1 compared to cancer cells of epithelial origin. Further, we find that MH1 treatment leads to cell cycle arrest at G2/M, at early time points in Molt4 cells. Finally multiple cellular assays demonstrate that MH1 treatment leads to reduction in MMP, induction of apoptosis by activating CASPASE 9 and CASPASE 3. Thus our study shows MH1, a novel DNA minor groove binder, induces cytotoxicity efficiently in leukemic cells by activating the intrinsic pathway of apoptosis.

Easy access for the synthesis of 2-aryl 2,3-dihydroquinazolin-4(1H)-ones using gem-dibromomethylarenes as synthetic aldehyde equivalent

One step synthesis of 2,3-dihydroquinazolin-4(1H)-ones from gem-dibromomethylarenes using 2-aminobenzamide is described. Gem-dibromomethylarenes are used as aldehyde equivalent for the efficient synthesis of 2,3-dihydroquinazolin-4(1H)-ones, this synthesis takes shorter reaction time with quick isolation and excellent product yield.

Novel Synthetic Oxazines Target NF-κB in Colon Cancer In Vitro and Inflammatory Bowel Disease In Vivo

Aberrant activation of nuclear factor kappa B (NF-κB) has been linked with the pathogenesis of several proinflammatory diseases including number of cancers and inflammatory bowel diseases. In the present work, we evaluated the anticancer activity of 1,2-oxazines derivatives against colorectal cancer cell lines and identified 2-((2-acetyl-6,6-dimethyl-4-phenyl-5,6-dihydro-2H-1,2-oxazin-3-yl)methyl)isoindoline-1,3-dione (API) as the lead anticancer agent among the tested compounds. The apoptosis inducing effect of API was demonstrated using flow cytometry analysis and measuring the caspase 3/7 activity in API treated cells. Based on the literature on inhibition of NF-κB by oxazines, we evaluated the effect of 1,2-oxazines against the ability of NF-κB binding to DNA, NF-κB-dependent luciferase expression and IκBα phosphorylation. We found that, API abrogate constitutive activation of NF-κB and inhibits IκBα phosphorylation in HCT116 cells. Our in silico analysis revealed the binding of oxazines to the hydrophobic cavity that present between the interface of p65 and IκBα. Given the relevance with aberrant activation of NF-κB in inflammation bowel disease (IBD), we evaluated the effect of API on dextran sulphate sodium-induced IBD mice model. The treatment of IBD induced mice with API decreased the myeloperoxidase activity in colonic extract, modulated the colon length and serum levels of pro- and anti-inflammatory cytokines such as TNF-α, IFN-γ, IL-6, IL-1β and IL-10. Furthermore, the histological analysis revealed the restoration of the distorted cryptic epithelial structure of colon in the API treated animals. In conclusion, we comprehensively validated the NF-κB inhibitory efficacy of API that targets NF-κB in in vitro colon cancer and an in vivo inflammatory bowel disease model.

Synthesis, Characterization and In Vitro Antiproliferative Effects of Novel 5-Amino Pyrazole Derivatives against Breast Cancer Cell Lines

In search of synthetic chemotherapeutic substances capable of inhibiting, retarding, or reversing the process of multistage carcinogenesis, we synthesised a series of novel 1-(4-methoxybenzyl)-3-cyclopropyl-1H-pyrazol-5-amine derivatives 9(a-h) by a nucleophilic substitution reaction and characterized by (1)H and (13)C nuclear magnetic resonance (NMR), liquid chromatography mass spectrometry (LC/MS), Fourier-transform infrared (FTIR), and elemental analysis. These novel compounds were evaluated for their efficacy in inhibiting VERO normal and MCF-7 breast cancer cells proliferation by trypan blue exclusion assay, MTT assay, [(3)H] thymidine incorporation assay and DNA fragmentation analysis. Among the series, some compounds exhibited interesting growth inhibitory effects against cell lines. From the Structure-Activity Relationship studies, it has been revealed that, both novel patented compounds and therapeutic protocols of N-terminal pyrazole ring structures play key role in the antiproliferative activity.

Synthesis and antiproliferative studies of curcumin pyrazole derivatives

A series of curcumin pyrazole derivatives (3a–e) were synthesized. The chemical structures were determined by 1H and 13C NMR spectroscopic techniques and their purity was confirmed by LC–MS and melting point determination. The compounds were screened for anticancer effects on different cancer cell lines by MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide) assay. The analogs demonstrated growth inhibitory effect on MCF-7, HeLa, and K562 cell lines with significant IC50 values. Compound 3b exhibited a high degree of cytotoxicity against cancer cells and minimum growth inhibitory effects against normal cells HEK293T and hence further, cell cycle analysis and mitochondrial membrane potential studies (JC-1 assay) were conducted by utilizing flow cytometry against K562 cells. This compound effectively arrested cell cycle progression at SubG1 phase and cells exhibited decreased membrane potential in a concentration-dependent manner with fluorescence shifting from red to green. Our findings suggest that compound 3b could be a promising anticancer agent since it effectively inhibited cell proliferation and can be selected for further in vitro and in vivo investigations.

Regioselective synthesis and biological studies of novel 1-aryl-3, 5-bis (het) aryl pyrazole derivatives as potential antiproliferative agents

Pyrazole moiety represents an important category of heterocyclic compound in pharmaceutical and medicinal chemistry. The novel 1-aryl-3, 5-bis (het) aryl pyrazole derivatives were synthesized with complementary regioselectivity. The chemical structures were confirmed by IR, 1H NMR, 13C NMR, and mass spectral analysis. The chemical entities were screened in various cancer cell lines to assess their cell viability activity. Results showed that the compound 3-(1-(4-bromophenyl)-5-phenyl-1H-pyrazol-3-yl) pyridine (5d) possessed maximum cytotoxic effect against breast cancer and leukemic cells. The cytotoxicity was confirmed by live–dead cell assay and cell cycle analysis. Mitochondrial membrane potential, Annexin V-FITC staining, DNA fragmentation, Hoechst staining, and western blot assays revealed the ability of compound 5d to induce cell death by activating apoptosis in cancer cells. Thus, the present study demonstrates that compound 5d could be an attractive chemical entity for the development of small molecule inhibitors for treatment of leukemia and breast cancer.

A trisubstituted pyrazole derivative reduces DMBA-induced mammary tumor growth in rats by inhibiting estrogen receptor-α expression

Aberrant expression of estrogen receptor alpha (ER-α) is observed in many pathological complications like breast cancer, endometrial cancer, and in osteoporosis. ER-α plays a vital role in the initiation and progression of breast cancer and confers chemo and radioresistance to the cancer cells by upregulating expression of anti-apoptotic proteins. The synthetic pyrazole derivative 3-(1-(4-bromophenyl)-5-phenyl-1H-pyrazol-3-yl)pyridine (compound 5d) displays significant cytotoxicity against mammary carcinoma cells. Molecular docking studies revealed that compound 5d binds to ligand binding domain of (ER-α). In vivo studies were carried out to investigate ER-α expression by immunohistochemistry and quantitative RT-PCR, which revealed reduction of ER-α in tumor cells upon treatment with compound 5d indicating its ER-α antagonistic effect. Our study ascertains compound 5d as a potent inhibitor of mammary carcinoma cells.