RNA interference therapeutics for cancer: challenges and opportunities

Abstract. RNA interference (RNAi) is a sequence-specific, post-transcriptional gene silencing mechanism in animals and plants, which is mediated by double-stranded RNA (dsRNA). There has recently been an increasing interest in harnessing the gene silencing activity of dsRNA to develop novel drugs for the treatment of various diseases, such as cancer, neurological disorders, age-related macular degeneration and viral infections. Small interfering RNA (siRNA)-based drugs have distinct advantages over conventional small molecule or protein-based drugs, including high specificity, higher potency and reduced toxicity. However, there are several technical obstacles to overcome before siRNA-based drugs reach the clinic. Delivery of siRNA to the target tissues and stability in the serum remain a major challenge and are the main focus of current research and development efforts. This review focused primarily on the progress made in developing RNAi as therapeutics for cancer and the challenges associated with its clinical development. Use of ligands recognizing cell-specific receptors to achieve tumor-specific delivery of siRNA, methods for enhanced siRNA delivery, improving the bioavailability and pharmacokinetic properties of siRNA and reducing the off-target effects and non-specific gene silencing are discussed in the light of current evidence

Evaluation of immune response to recombinant potential protective antigens of Mycoplasma hyopneumoniae delivered as cocktail DNA and/or recombinant protein vaccines in mice

Intramuscular immunization of mice with DNA cocktail vaccines, comprising potential protective antigens P36, P46, NrdF, and P97or P97R1 of Mycoplasma hyopneumoniae, induced strong Th1-polarized immune responses against each antigen, with only P46 eliciting a serum IgG response. Subcutaneous immunization with protein cocktail vaccines, surprisingly, induced both Th1-polarized immune response as well as antibody response whereas mice immunized with DNA cocktail vaccines followed by boosting with protein cocktail vaccines generated strong Th1-polarized and humoral immune responses. P97 was not recognized by serum antibodies from commercial bacterin-immunized mice indicating potential lack of expression of this important antigen in inactivated whole-cell vaccines

Comparative studies of the immunogenicity and protective potential of biofilm vs planktonic Staphylococcus aureus vaccine against bovine mastitis using non-invasive mouse mastitis as a model system

This study was undertaken to compare the immunogenicity and protective potential of biofilm vs planktonic Staphylococcus aureus vaccine for the prevention of mastitis using the mouse as a model system. Mice immunized with formalin-killed whole cell vaccine of S. aureus residing in a biofilm when delivered via an intramammary route produced a cell mediated immune response. Mice immunized with this biofilm vaccine showed significant reductions in colonization by S. aureus in mammary glands, severity of clinical symptoms and tissue damage in mammary glands in comparison with the mice immunized with formalin-killed whole cells of planktonic S. aureus. The planktonic vaccine administered by a subcutaneous route produced a significantly higher humoral immune response (IgG1 and IgG) than the biofilm vaccine. However, considering the host response, tissue damage, the clinical severity and colonization of S. aureus in mammary glands, the biofilm vaccine performed better in immunogenicity and protective potential when administered by the intramammary route

Soirée inaugurale du festival Histoire et Cité, rencontres de Genève sur le thème «Construire la Paix» en mai 2015: intervention de Rolf Heuer, directeur général du CERN.

Soirée inaugurale du festival Histoire et Cité, rencontres de Genève sur le thème «Construire la Paix» en mai 2015: intervention de Rolf Heuer, directeur général du CERN

Relative distribution of virulence-associated factors among Australian bovine staphylococcus aureus isolates: potential relevance to development of an effective bovine mastitis vaccine

Staphylococcus aureus is one of the major contagious pathogens causing bovine mastitis worldwide.1 It causes contagious mastitis resulting either clinical or subclinical mastitis with increase in the number of somatic cell count (SCC) in milk. More than $130 million is lost by the Australian dairy farmers ($A200/cow/year) every year due to poor udder health caused by mastitis resulting in reduction of milk production, increase in treatment costs, veterinary consultation fees, and number of cow culls. There are multiple pathogens that have been found to be associated with bovine mastitis in Australia.2 While the relative distribution of the different pathogens causing mastitis may differ in different regions and countries, S. aureus is one of the most significant contagious bacterial pathogens causing bovine mastitis and is of concern to public health because of its potential for transmission to humans..

Polymerase chain reaction for the identification of bacteria.

<p>Genomic DNA was isolated from the obtained isolates as well as reference strains, and subjected to mono- or multi-plex PCR as described in the Materials and Methods and <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0142717#pone.0142717.t001" target="_blank">Table 1</a>. The experiments were repeated at least three times and representative gel pictures are shown. Note that each panel is composed from two separate gels since all the samples could not be accommodated in a single gel. <b>(A) PCR for genus-specific <i>tuf</i> genes of streptococci and staphylococci.</b> Lane designation: M, 100 bp ladder; 1–5, <i>Streptococcus</i> spp. isolates; 6, Reference strain Streptococcus AD1; 7, No template control for streptococcus; 8, Negative control (<i>S</i>. <i>aureus</i>, <i>E</i>. <i>coli</i>); 9, Reagent control; 10, Reference strain <i>S</i>. <i>aureus</i> 96; 11, No template control for staphylococcus; 12–18: <i>Staphylococcus</i> spp. isolates. <b>PCR for <i>S</i>. <i>aureus nuc</i> (lanes 1–11) and <i>E</i>. <i>coli alr</i> (lanes 12–21) genes.</b> Lane designation: M, 100 bp ladder; 1–8, <i>S</i>. <i>aureus</i> test isolates; 9, Reference strain SAU-3; 10, Negative control (<i>E</i>. <i>coli</i>); 11, No template control; 12, Negative control (<i>S</i>. <i>aureus</i>); 13, Reference strain EC11 (<i>E</i>. <i>coli</i>); 14–16, Test isolates of <i>E</i>. <i>coli</i>; 17, No template control; 18–20, Test isolates; 21, Negative control (streptococcus). <b>(B) PCR for the identification of CoNS species.</b> Lane designation: M, 100 bp ladder; 1, <i>S</i>. <i>haemolyticus</i> (MTCC 3383) control; 2, <i>S</i>. <i>sciuri</i> (MTCC 6154) control; 3, <i>S</i>. <i>saprophyticus</i> (MTCC 6155) control; 4, <i>S</i>. <i>arlettae</i> (JQ764624) control; 5, <i>S</i>. <i>chromogenes</i> (MTCC 3545) control; 6, <i>S</i>. <i>sciuri</i> (MTCC 6154) control; 7, <i>S</i>. <i>xylosus</i> (FJ90627.1) control; 8, <i>S</i>. <i>simulans</i> (AF495498.1) control; 9, <i>S</i>. <i>epidermidis</i> (MTCC 3615) control; 10, <i>S</i>. <i>haemolyticus</i> (MTCC 3383) control; 11, <i>S</i>. <i>sciuri</i> (MTCC 6154) control; 12, <i>S</i>. <i>saprophyticus</i> (MTCC 6155) control; 13, <i>S</i>. <i>arlettae</i> (JQ764624) control; 14, <i>S</i>. <i>chromogenes</i> (MTCC 3545) control; 15, <i>S</i>. <i>sciuri</i> (MTCC 6154) control; 16, <i>S</i>. <i>simulans</i> (AF495498.1) control; 17, <i>S</i>. <i>xylosus</i> (FJ90627.1) control; 18, <i>S</i>. <i>epidermidis</i> (MTCC 3615) control. This Panel represents two mutually exclusive pictures depicting the results of the standardization of one tube each of the two-tube multiplex PCR. In the left panel, primers for <i>S</i>. <i>arlettae</i>, <i>S</i>. <i>chromogenes</i>, <i>S</i>. <i>sciuri</i>, <i>S</i>. <i>epidermidis</i> and <i>S</i>. <i>saprophyticus</i> were used, and <i>S</i>. <i>haemolyticus</i>, <i>S</i>. <i>xylosus</i> and <i>S</i>. <i>simulans</i> DNA served as negative controls. In the right panel, primers for <i>S</i>. <i>equorum</i>, <i>S</i>. <i>haemolyticus</i>, <i>S</i>. <i>xylosus</i>, <i>S</i>. <i>simulans</i> and <i>S</i>. <i>fluerettii</i> were used, and <i>S</i>. <i>sciuri</i>, <i>S</i>. <i>sapryphyticus</i>, <i>S</i>. <i>arlettae</i>, <i>S</i>. <i>chromogenes</i> and <i>S</i>. <i>epidermidis</i> DNA served as negative controls. Numbers in parentheses indicate the GenBank Accession numbers or the MTCC culture designations. <b>(C) PCR for the identification of <i>Streptococcus</i> species.</b> Lane designation: M, 100 bp ladder; 1–20, Test streptococcal isolates streptococci (no amplification); 21, Negative control (<i>S</i>. <i>aureus</i>); 22, Negative control (<i>E</i>. <i>coli</i>); 23 & 24, No template control; 25, Tube 2 positive control (<i>Streptococcus</i> reference strain AD3); 26, Tube 1 positive controls (<i>Streptococcus</i> reference strains AD1 and AD6).</p

Not Available

Not AvailableBiofilm formation is an important virulence determinant of Staphylococcus aureus which is a major etiological agent of bovine mastitis. Here, 132 bovine mastitis-associated S. aureus were subjected to biofilm production, antimicrobial susceptibility, and the detection of ica, bap, agr and blaZ genes. It was found that 33.3% of the isolates produced biofilm. The number of isolates resistant to individual antibiotics increased by 1.2- to 7.0-fold when growing in biofilm versus planktonic mode of growth, and the spectrum of antibiotics as well as the number of isolates resistant to various antibiotics increased with the increase in the density of the biofilm. However, there was no correlation between the strength of biofilm and the extent of antibiotic resistance. When evaluated for the presence of genes reported to be associated with biofilm formation, bap gene was detected in a significant number (12.9%) of the isolates.Not Availabl

An immunological assay for identification of potential biofilm-associated antigens of Staphylococcus aureus

Attachment of bacterial pathogens to the niche tissue in the host is the first step in biofilm formation leading to colonization and establishment of infection in the host. While the most common method used for determining the potential role of a bacterial antigen in biofilm formation has been demonstration of loss of this property using specific knockout mutants, it is an expensive and a laborious procedure. This study describes an alternative immunological assay for identification of attachment antigens of Staphylococcus aureus, potentially important in the development of an effective vaccine against infections caused by this pathogen. The method is based upon the concept of inhibition of attachment of S. aureus to PEGs coated with virulence antigen-specific antibodies. Antibodies used for validation of this assay were specific for ClfA, FnBPA, SdrD, PNAG and a-toxin, accredited biofilm-associated antigens of S. aureus

Parenteral immunization of mice with a genetically inactivated pertussis toxin DNA vaccine induces cell-mediated immunity and protection

The immunogenicity and protective efficacy of a DNA vaccine encoding a genetically inactivated S1 domain of pertussis toxin was evaluated using a murine respiratory challenge model of Bordetella pertussis infection. It was found that mice immunized via the intramuscular route elicited a purely cell-mediated immune response to the DNA vaccine, with high levels of gamma interferon (IFN-c) and interleukin (IL)-2 detected in the S1-stimulated splenocyte supernatants and no serum IgG. Despite the lack of an antibody response, the lungs of DNA-immunized mice were cleared of B. pertussis at a significantly faster rate compared with mock-immunized mice following an aerosol challenge. To gauge the true potential of this S1 DNA vaccine, the immune response and protective efficacy of the commercial diphtheria–tetanus–acellular pertussis (DTaP) vaccine were included as the gold standard. Immunization with DTaP elicited a typically strong T-helper (Th)2-polarized immune response with significantly higher titres of serum IgG than in the DNA vaccine group, but a relatively weak Th1 response with low levels of IFN-c and IL-2 detected in the supernatants of antigen-stimulated splenocytes. DTaP-immunized mice cleared the aerosol challenge more efficiently than DNA-immunized mice, with no detectable pathogen after day 7 post-challenge