Triazole tethered isatin-coumarin based molecular hybrids as novel antitubulin agents: Design,synthesis, biological investigation and docking studies

In an attempt to develop potent anti-tubulin agents against most dreadful disease cancer, a library of 28 novel triazole tethered isatin-coumarin hybrids were synthesized by click chemistry approach. Synthesized hybrids were characterized and evaluated against a panel of human cancer cell lines viz. THP-1, COLO-205, HCT-116 and PC-3. Biological assay unveiled that, compounds A-1 to A-6, B-1 to B-4 and C-1 to C-3 displayed significant inhibitory potential against THP-1, COLO-205 and HCT-116 cell lines which were more sensitive towards the designed hybrids. PC-3 among these cell lines was found to be almost resistant. Established SAR revealed marked dependence of the cytotoxic activity on the type of substituent on isatin and the length of carbon-bridge connecting isatin moiety with triazole ring. Unsubstituted isatin and two carbon-bridge were found to be crucial for cytotoxicity. Three most potent hybrids (A-1, A-2 and B-1) were further tested for tubulin polymerization inhibition. Among these three compounds, A-1 found to be endowed with most prominent tubulin polymerization inhibition potential with IC₅₀ value of 1.06 µM which was further confirmed by using confocal microscopy. Possible binding interactions between the most potent hybrid molecule A-1 and tubulin were also divulged by molecular modeling studies.     

Systems biology-defined NF-κB regulons, interacting signal pathways and networks are implicated in the malignant phenotype of head and neck cancer cell lines differing in p53 status

Background  

Aberrant activation of the nuclear factor kappaB (NF-κB) pathway has been previously implicated as a crucial signal promoting tumorigenesis. However, how NF-κB acts as a key regulatory node to modulate global gene expression, and contributes to the malignant heterogeneity of head and neck cancer, is not well understood.     

9‐bromonoscapine‐induced mitotic arrest of cigarette smoke condensate‐transformed breast epithelial cells

In the present investigation, we determined the chemotherapeutic efficacy of 9‐bromonoscapine (Br‐Nos), a more potent noscapine analog, on MCF10A, spontaneously immortalized human normal breast epithelial cells and MCF10A‐CSC3, cigarette smoke condensate (CSC)‐transformed cells. The results from cytogenetic analysis showed that Br‐Nos induced polyploidy and telomeric association in MCF10A‐CSC3 cells, while MCF10A cells remained unaffected. Our immunofluorescence data further demonstrated that MCF10A‐CSC3 cells were susceptible to mitotic catastrophe on exposure to Br‐Nos and failed to recover after drug withdrawal. MCF10A‐CSC3 cells exhibited Br‐Nos‐induced aberrant multipolar spindle formation, which irreversibly impaired the alignment of replicated chromosome to the equatorial plane and finally culminated in cell death. Although MCF10A cells upon Br‐Nos treatment showed bipolar spindles with some uncongressed chromosomes, these cells recovered fairly well after drug withdrawal. Our flow‐cytometry analysis data reconfirmed that MCF10A‐CSC3 cells were more susceptible to cell death compared to MCF10A cells. Furthermore, our results suggest that decreased levels of cdc2/cyclin B1 and cdc2 kinase activity are responsible for Br‐Nos‐induced mitotic cell arrest leading to cell death in MCF10A‐CSC3 cells. This study thus explores the underlying mechanism of Br‐Nos‐induced mitotic catastrophe in CSC‐transformed MCF10A‐CSC3 cells and its potential usefulness as a chemotherapeutic agent for prevention of cigarette smoke‐induced breast cancer growth. J. Cell. Biochem. 106: 1146–1156, 2009. © 2009 Wiley‐Liss, Inc.     

The encapsulation technology in fruit plants—A review

Encapsulation technology is an exciting and rapidly growing area of biotechnological research. This has drawn tremendous attention in recent years because of its wide use in conservation and delivery of tissue cultured plants of commercial and economic importance. Production of synthetic seeds by encapsulating somatic embryos, shoot buds or any other meristmatic tissue helps in minimizing the cost of micropropagated plantlets for commercialization and final delivery. In most of fruit crops, seed propagation has not been successful because of heterozygosity of seeds, minute seed size, presence of reduced endosperm, low germination rate, and also some are having seedless varieties. Many species have desiccation-sensitive intermediate or recalcitrant seeds and can be stored for only a few weeks or months. Under these circumstances, increasing interest has been shown recently to use encapsulation technology for propagation and conservation. Many fruit plants are studied worldwide for breeding, genetic engineering, propagation, and pharmaceutical purposes. In this context, synthetic seeds would be more applicable in exchange of elite and axenic plant material between laboratories and extension centers due to small bead size and ease in handling. Due to these advantages, interest in using encapsulation technology has continuously been increasing in several fruit plant species. The purpose of this review is to focus upon current information on development of synthetic seeds in several fruit crops.     

Modulation of biocidal activity of <Emphasis Type="Italic">Calothrix</Emphasis> sp. and <Emphasis Type="Italic">Anabaena</Emphasis> sp. by environmental factors

An investigation was undertaken to evaluate a set of cyanobacterial strains in terms of production of biocidal compounds exhibiting allelochemical and fungicidal properties. Two cyanobacterial strains — Anabaena sp. and Calothrix sp. were selected for further investigation, on the basis of their larger inhibition zones on the lawn of Synechocystis and Synechococcus sp. and two phytopathogenic fungi — Rhizoctonia bataticola and Pythium debaryanum. The diameter of the inhibition zone was largest when extracellular filtrates of the two cultures incubated at high light intensity (90–100 μmol photons m⁻² s⁻¹) and temperature (40 ± 2 °C) or grown in medium containing two-folds higher P (1.4 mg/L, as compared to 0.7 mg/L in BG 11 medium) were taken. A pH of 8 was the most optimal for both strains, in terms of growth and biocidal activity. Partial purification of ethyl acetate extract using TLC, followed by GLC revealed a single peak. This study highlights the importance of environmental factors in aggravating or reducing the toxic effects of these harmful cyanobacteria and their potential as a biocontrol agent.     

SNP discovery from next-generation transcriptome sequencing data and their validation using KASP assay in wheat (<Emphasis Type="Italic">Triticum aestivum</Emphasis> L.)

Single nucleotide polymorphisms (SNPs) are becoming the most amenable form of DNA-based molecular markers for genetic analysis. In hexaploid bread wheat (Triticum aestivum L.), it is difficult to discern true polymorphic SNPs due to homoeologous and paralogous genes. Two serial analysis of gene expression (SAGE) libraries were developed utilizing leaves from resistant plants carrying leaf rust resistance gene Lr28; one library was derived from leaves that were mock inoculated and the other was derived from leaves inoculated with the urediniospores of the leaf rust pathogen Puccinia triticina. Next-generation sequencing reads, after quality trimming and removal of fungal sequences, were mapped to wheat reference sequences at Ensembl Plants. CLC Genomics Workbench and Freebayes softwares were employed for SNP calling. A total of 611 SNPs were predicted to be common by both softwares, of which 207 varietal SNPs were identified by ConservedPrimer software. A subset of 100 SNPs was used for validation across 47 wheat genotypes using Kompetitive Allele Specific PCR (KASP) assay; 83 SNPs could be successfully validated. These SNPs were positioned on wheat subgenomes and chromosome arms. When functionally annotated, many sequences harboring SNPs showed homology to resistance and resistance-like genes listed in Plant Resistance Gene database (PRGdb) as well as pathogenesis-related (PR) and stress-responsive genes. The results of the present study involving discovery of SNPs associated with resistance to leaf rust, a major threat to wheat production worldwide, will be valuable for molecular breeding for rust resistance.     

Diglyceride prodrug strategy for enhancing the bioavailability of norfloxacin

Prodrug approach using diglyceride as a promoiety is a promising strategy to improve bioavailability of poorly absorbed drugs and the same was explored in the present work to improve oral bioavailability of norfloxacin; a second generation fluoroquinolone antibacterial. The prodrug was synthesized by standard procedures using dipalmitine as a carrier and the structure was confirmed by spectral analysis. Higher Log P indicated improved lipophilicity. The ester linkage between norfloxacin and dipalmitine would be susceptible to hydrolysis by lipases to release the parent drug and carrier in the body. In vivo kinetic studies in rats indicated 53% release of norfloxacin in plasma at the end of 8 h. The prodrug exhibited improved pharmacological profile than the parent compound at equimolar dose that indirectly indicated improved bioavailability.