Cell specific apoptosis by RLX is mediated by NFκB in human colon carcinoma HCT-116 cells

BACKGROUND: Resistance to chemotherapy represents a major obstacle in correcting colorectal carcinomas (CRC). Inspite of recent advances in the treatment of metastatic disease, the prognosis of the patients remains poor. RLX, a vasicinone analogue has been reported to possess potent bronchodilator, anti-asthmatic and anti-inflammatory properties. However, its anti-cancer activity is unknown. RESULTS: Here, we report for the first time that RLX has anti-cancer property against panel of human cancer cell lines and most potent activity was found against HCT-116 cells with IC(50) value of 12 μM and have further investigated the involvement of NFκB and caspase-3 in RLX action in CRC apoptosis. Following RLX and BEZ-235 treatment in HCT-116, we observed significant down-regulation of NFκB (1 to 0.1 fold) and up-regulation of caspase-3 (1 to 2 fold) protein expressions. Additionally, morphological studies revealed membrane blebbing, cell shrinkage, chromatin condensation and finally apoptosis in HCT-116 cells. CONCLUSIONS: Overall, these findings indicate that RLX is a potent small molecule which triggers apoptosis, and promising potential candidate to be a chemotherapeutic agent

Human rhinovirus-induced inflammatory responses are inhibited by phosphatidylserine containing liposomes

Human rhinovirus (HRV) infections are major contributors to the healthcare burden associated with acute exacerbations of chronic airway disease, such as chronic obstructive pulmonary disease and asthma. Cellular responses to HRV are mediated through pattern recognition receptors that may in part signal from membrane microdomains. We previously found Toll-like receptor signaling is reduced, by targeting membrane microdomains with a specific liposomal phosphatidylserine species, 1-stearoyl-2-arachidonoyl-sn-glycero-3-phospho-L-serine (SAPS). Here we explored the ability of this approach to target a clinically important pathogen. We determined the biochemical and biophysical properties and stability of SAPS liposomes and studied their ability to modulate rhinovirus-induced inflammation, measured by cytokine production, and rhinovirus replication in both immortalized and normal primary bronchial epithelial cells. SAPS liposomes rapidly partitioned throughout the plasma membrane and internal cellular membranes of epithelial cells. Uptake of liposomes did not cause cell death, but was associated with markedly reduced inflammatory responses to rhinovirus, at the expense of only modest non-significant increases in viral replication, and without impairment of interferon receptor signaling. Thus using liposomes of phosphatidylserine to target membrane microdomains is a feasible mechanism for modulating rhinovirus-induced signaling, and potentially a prototypic new therapy for viral-mediated inflammation

Synthetic RNA Silencing of Actinorhodin Biosynthesis in Streptomyces coelicolor A3(2)

We demonstrate the first application of synthetic RNA gene silencers in Streptomyces coelicolor A3(2). Peptide nucleic acid and expressed antisense RNA silencers successfully inhibited actinorhodin production. Synthetic RNA silencing was target-specific and is a new tool for gene regulation and metabolic engineering studies in Streptomyces.Peer reviewe

The antimicrobial polymer PHMB enters cells and selectively condenses bacterial chromosomes

To combat infection and antimicrobial resistance, it is helpful to elucidate drug mechanism(s) of action. Here we examined how the widely used antimicrobial polyhexamethylene biguanide (PHMB) kills bacteria selectively over host cells. Contrary to the accepted model of microbial membrane disruption by PHMB, we observed cell entry into a range of bacterial species, and treated bacteria displayed cell division arrest and chromosome condensation, suggesting DNA binding as an alternative antimicrobial mechanism. A DNA-level mechanism was confirmed by observations that PHMB formed nanoparticles when mixed with isolated bacterial chromosomal DNA and its effects on growth were suppressed by pairwise combination with the DNA binding ligand Hoechst 33258. PHMB also entered mammalian cells, but was trapped within endosomes and excluded from nuclei. Therefore, PHMB displays differential access to bacterial and mammalian cellular DNA and selectively binds and condenses bacterial chromosomes. Because acquired resistance to PHMB has not been reported, selective chromosome condensation provides an unanticipated paradigm for antimicrobial action that may not succumb to resistance

Species-selective killing of bacteria by antimicrobial peptide-PNAs

This is an open-access article distributed under the terms of the Creative Commons Attribution License, CC BY 4.0 which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.Broad-spectrum antimicrobials kill indiscriminately, a property that can lead to negative clinical consequences and an increase in the incidence of resistance. Species-specific antimicrobials that could selectively kill pathogenic bacteria without targeting other species in the microbiome could limit these problems. The pathogen genome presents an excellent target for the development of such antimicrobials. In this study we report the design and evaluation of species-selective peptide nucleic acid (PNA) antibacterials. Selective growth inhibition of B. subtilis, E. coli, K. pnuemoniae and S. enterica serovar Typhimurium in axenic or mixed culture could be achieved with PNAs that exploit species differences in the translation initiation region of essential genes. An S. Typhimurium-specific PNA targeting ftsZ resulted in elongated cells that were not observed in E. coli, providing phenotypic evidence of the selectivity of PNA-based antimicrobials. Analysis of the genomes of E. coli and S. Typhimurium gave a conservative estimate of >150 PNA targets that could potentially discriminate between these two closely related species. This work provides a basis for the development of a new class of antimicrobial with a tuneable spectrum of activity.Peer reviewedFinal Published versio

Alveolar macrophages are sentinels of murine pulmonary homeostasis following inhaled antigen challenge.

BACKGROUND: Alveolar macrophages are sentinels of the pulmonary mucosa and central to maintaining immunological homeostasis. However, their role in governing the response to allergen is not fully understood. Inappropriate responses to the inhaled environment manifest as asthma. METHODS: We utilized a mechanistic IL-13-driven model and a house dust mite allergen mucosal sensitization model of allergic airway disease to investigate the role of alveolar macrophages in regulating pulmonary inflammation. RESULTS: IL-13-dependent eosinophilic and Th2 inflammation was enhanced in mice depleted of alveolar macrophages using clodronate liposomes. Similarly, depletion of alveolar macrophages during house dust mite sensitization or established disease resulted in augmented Th2 immunity and increased allergen-specific IgG1 and IgE. Clodronate treatment also delayed the resolution of tissue inflammation following cessation of allergen challenge. Strikingly, tissue interstitial macrophages were elevated in alveolar macrophage-deficient mice identifying a new homeostatic relationship between different macrophage subtypes. A novel role for the macrophage-derived immunoregulatory cytokine IL-27 was identified in modulating Th2 inflammation following mucosal allergen exposure. CONCLUSIONS: In summary, alveolar macrophages are critical regulators of Th2 immunity and their dysregulation promotes an inflammatory environment with exacerbation of allergen-induced airway pathology. Manipulating IL-27 may provide a novel therapeutic strategy for the treatment of asthma

Chemically Standardized Isolates from Cedrus deodara Stem Wood having Anticancer Activity

An isolate ”CD lignan mixture” comprising lignans from stem wood of Cedrus deodara consisted of (-)-wikstromal (75 - 79 %), (-)-matairesinol (9 - 13 %) and benzylbutyrolactol (7 - 11 %) and was studied for its in vitro cytotoxcity against human cancer cell lines. The in vivo anticancer activity of CD lignan mixture was studied using Ehrlich ascites carcinoma and colon carcinoma (CA-51) models in mice. Its effect was also studied on annexin V binding, intracellular caspases and DNA fragmentation to gain insight into the mode of action. In vitro cytotoxicity studies showed significant dose-dependent effects against several cancer cell lines from different tissues such as breast, cervix, neuroblastoma, colon, liver, and prostrate at 10, 30 and 100 μg/mL. The IC50 values varied from 16.4 ng/mL to 116.03 μg/mL depending on the cell line. Comparative data of IC50 values of CD lignan mixture showed a synergistic effect in comparision to the individual molecules, i. e., (-)-matairesinol, (-)-wikstromol present in CD lignand mixture. CD lignan mixture had the most pronounced effect on CNS cell lines followed by colon. The tumor regression observed with Ehrlich ascites carcinoma and CA-51 was 53 % and ∼54 %, respectively, when CD lignan mixture was given at 300 mg/kg, i. p. for nine days in the Ehrlich ascites carcinoma model and 400 mg/kg, i. p. for the same period in the CA-51 model. It was comparable with 5-fluorouracil at 22 mg/kg and 20 mg/kg, respectively. CD lignan mixture at 10, 30 and 100 μg/mL increased the percentage of annexinV positive HL-60 cells to 1.9 - 17.18 % as compared to control (1.04 %). In K562 cells CD lignan mixture at 10, 30 or 100 μg/mL and staurosporine (1 μM) showed 9.13 %, 11.38 %, 17.22 % and 28.07 % intacellular caspases activation, respectively. A distinct DNA laddering pattern was observed for treatment with the CD lignan mixture in HL-60, K562 (30 μg/mL and 100 μg/mL) and MOLT-4 cells (30 μg/mL) after 24 h incubation. DNA cell cycle analysis indicated that CD lignan mixture at 10, 30 and 100 μg/mL increased the content of hypodiploid (sub G1 phase) cells when compared to control (2.55, 5.4 and 6.25 % vs. 0.27 %). The present study indicates that CD lignan mixture has cytotoxic potential against human cancer cell lines. It has the ability to induce tumor regression in vivo. It induces apoptosis as indicated by annexin V positive cells, induction of intracellular caspases, DNA fragmentation and DNA cell cycle analysis