Cloning and characterization of 2-C-methyl-D-erythritol-4-phosphate pathway genes for isoprenoid biosynthesis from Indian ginseng, Withania somnifera

Withania somnifera (L.) is one of the most valuable medicinal plants used in Ayurvedic and other indigenous medicines. Pharmaceutical activities of this herb are associated with presence of secondary metabolites known as withanolides, a class of phytosteroids synthesized via mevalonate (MVA) and 2-C-methyl-d-erythritol-4-phosphate pathways. Though the plant has been well characterized in terms of phytochemical profiles as well as pharmaceutical activities, not much is known about the genes responsible for biosynthesis of these compounds. In this study, we have characterized two genes encoding 1-deoxy-d-xylulose-5-phosphate synthase (DXS; EC 2.2.1.7) and 1-deoxy-d-xylulose-5-phosphate reductase (DXR; EC 1.1.1.267) enzymes involved in the biosynthesis of isoprenoids. The full-length cDNAs of W. somnifera DXS (WsDXS) and DXR (WsDXR) of 2,154 and 1,428 bps encode polypeptides of 717 and 475 amino acids residues, respectively. The expression analysis suggests that WsDXS and WsDXR are differentially expressed in different tissues (with maximal expression in flower and young leaf), chemotypes of Withania, and in response to salicylic acid, methyl jasmonate, as well as in mechanical injury. Analysis of genomic organization of WsDXS shows close similarity with tomato DXS in terms of exon–intron arrangements. This is the first report on characterization of isoprenoid biosynthesis pathway genes from Withania.     

Replication of Type 2 Diabetes Candidate Genes Variations in Three Geographically Unrelated Indian Population Groups

Type 2 diabetes (T2D) is a syndrome of multiple metabolic disorders and is genetically heterogeneous. India comprises one of the largest global populations with highest number of reported type 2 diabetes cases. However, limited information about T2D associated loci is available for Indian populations. It is, therefore, pertinent to evaluate the previously associated candidates as well as identify novel genetic variations in Indian populations to understand the extent of genetic heterogeneity. We chose to do a cost effective high-throughput mass-array genotyping and studied the candidate gene variations associated with T2D in literature. In this case-control candidate genes association study, 91 SNPs from 55 candidate genes have been analyzed in three geographically independent population groups from India. We report the genetic variants in five candidate genes: TCF7L2, HHEX, ENPP1, IDE and FTO, are significantly associated (after Bonferroni correction, p<5.5E−04) with T2D susceptibility in combined population. Interestingly, SNP rs7903146 of the TCF7L2 gene passed the genome wide significance threshold (combined P value = 2.05E−08) in the studied populations. We also observed the association of rs7903146 with blood glucose (fasting and postprandial) levels, supporting the role of TCF7L2 gene in blood glucose homeostasis. Further, we noted that the moderate risk provided by the independently associated loci in combined population with Odds Ratio (OR)<1.38 increased to OR = 2.44, (95%CI = 1.67–3.59) when the risk providing genotypes of TCF7L2, HHEX, ENPP1 and FTO genes were combined, suggesting the importance of gene-gene interactions evaluation in complex disorders like T2D.     

Novel limonene and citral based 2,5-disubstituted-1,3,4-oxadiazoles: A natural product coupled approach to semicarbazones for antiepileptic activity

Two novel series of N⁴-(5-(2/3/4-substituted-phenyl)-1,3,4-oxadiazol-2-yl)-N¹-(2-methyl-5-(prop-1-en-2-yl)cyclohex-2-enylidene)semicarbazide and N⁴-(5-(2/3/4-substituted-phenyl)-1,3,4-oxadiazol-2-yl)-N¹-(3,7-dimethylocta-3,6-dienylidene)-semicarbazide were synthesized to meet structural prerequisite indispensable for anticonvulsant activity. The anticonvulsant activities of the compounds were investigated using maximal electroshock seizure (MES), subcutaneous pentylenetrtrazole (scPTZ) and subcutaneous strychnine (scSTY) models. The rotorod test was conducted to evaluate neurotoxicity. Some of the selected active compounds were subjected to GABA assay to confirm their mode of action. The outcome of the present investigations proved that the four binding sites pharmacophore model is vital for anticonvulsant activity. The efforts were also made to establish structure–activity relationships among test compounds.     

Inhibition of EGFR-AKT Axis Results in the Suppression of Ovarian Tumors In Vitro and in Preclinical Mouse Model

Ovarian cancer is the leading cause of cancer related deaths in women. Genetic alterations including overexpression of EGFR play a crucial role in ovarian carcinogenesis. Here we evaluated the effect of phenethyl isothiocyanate (PEITC) in ovarian tumor cells in vitro and in vivo. Oral administration of 12 μmol PEITC resulted in drastically suppressing ovarian tumor growth in a preclinical mouse model. Our in vitro studies demonstrated that PEITC suppress the growth of SKOV-3, OVCAR-3 and TOV-21G human ovarian cancer cells by inducing apoptosis in a concentration-dependent manner. Growth inhibitory effects of PEITC were mediated by inhibition of EGFR and AKT, which are known to be overexpressed in ovarian tumors. PEITC treatment caused significant down regulation of constitutive protein levels as well as phosphorylation of EGFR at Tyr1068 in various ovarian cancer cells. In addition, PEITC treatment drastically reduced the phosphorylation of AKT which is downstream to EGFR and disrupted mTOR signaling. PEITC treatment also inhibited the kinase activity of AKT as observed by the down regulation of p-GSK in OVCAR-3 and TOV-21G cells. AKT overexpression or TGF treatment blocked PEITC induced apoptosis in ovarian cancer cells. These results suggest that PEITC targets EGFR/AKT pathway in our model. In conclusion, our study suggests that PEITC could be used alone or in combination with other therapeutic agents to treat ovarian cancer.     

Design,synthesis and in vitro cytotoxicity studies of novel β-carbolinium bromides

A series of novel β-carbolinium bromides has been synthesized from easily accessible β-carbolines and 1-aryl-2-bromoethanones. The newly synthesized compounds were evaluated for their in vitro anticancer activity. Among the synthesized derivatives, compounds 16l, 16o and 16s exhibited potent anticancer activity with IC₅₀ values of <10 μM against tested cancer cell lines. The most potent analogue 16l was broadly active against all the tested cancer cell lines (IC₅₀ = 3.16–7.93 μM). In order to test the mechanism of cell death, we exposed castration resistant prostate cancer cell line (C4-2) to compounds 16l and 16s, which resulted in increased levels of cleaved PARP1 and AO/EB staining, indicating that β-carbolinium salts induce apoptosis in these cells. Additionally, the most potent β-carbolines 16l and 16s were found to inhibit tubulin polymerization.     

Discovery of VEGFR inhibitors through virtual screening and energy assessment

Vascular endothelial growth factor receptor-2 (VEGFR-2) is crucial in promoting tumor angiogenesis and cancer metastasis. Thus, inhibition of VEGFR-2 has appeared as a good tactic for cancer treatment. To find out novel VEGFR-2 inhibitors, first, the PDB structure of VEGFR-2, 6GQO, was selected based on atomic nonlocal environment assessment (ANOLEA) and PROCHECK assessment. 6GQO was then further used for structure-based virtual screening (SBVS) of different molecular databases, including US-FDA approved drugs, US-FDA withdrawn drugs, may bridge, MDPI, and Specs databases using Glide. Based on SBVS, receptor fit, drug-like filters, and absorption, distribution, metabolism, excretion, and toxicity (ADMET) analysis of 427877 compounds, the best 22 hits were selected. From the 22 hits, hit 5 complex with 6GQO was put through molecular mechanics/generalized born surface area (MM/GBSA) study and hERG binding. The MM/GBSA study revealed that hit 5 possesses lesser binding free energy with more inferior stability in the receptor pocket than the reference compound. The VEGFR-2 inhibition assay of hit 5 disclosed an IC₅₀ of 165.23 nM against VEGFR-2, which can be possibly enhanced through structural modifications.