History of how viruses can fight cancer: From the miraculous healings to the approval of oncolytic viruses

Since the nineteenth century, several reports in the historical medical literature emphasized that, occasionally, cancer patients showed a clinical remission, called "Saint Peregrine tumor" as a result of natural infections. Moreover, additional evidence indicated that viruses show a tropism toward cancer cells, leading to the discovery of oncolytic activity of several viruses, called oncolytic viruses (OVs). With the technological and scientific advancements, the advent of rodent models, the establishment of in vitro cell lines, the introduction of methods for virus propagation, several attempts through the 1950s and 1970s have been made to increase OVs specificity, efficacy and safety; however, inconclusive/negative results have been reached and many researchers abandoned the field. Only in the later 1990s, the genetic engineering and the recombinant DNA techniques that allowed the generation of potent, specific and safe OVs and a better understanding of cancer cells renewed the interest in virotherapy. Currently, virotherapy represents a cancer therapeutic strategy based on the use of OVs that selectively infect and lyse cancer cells, without harming normal cells. Over the past years, several "natural" and "genetic engineered" viruses, have been investigated in clinical studies and some of them revealed encouraging results. Recently, the clinical use of OVs has also been supported by the immune stimulatory property of OVs against tumor cells. Here, we analyze the early oncolytic virotherapy before genetic engineering to highlight the relevant progresses reached, and the mechanism to stimulate host immune response, a significant challenge in current virotherapy field.

Diel rhythm of the inflammatory cytokine il1b in the Japanese medaka (Oryzias latipes) regulated by core components of the circadian clock

In recent years, studies on circadian control in immunity have been actively conducted in mammals, but little is known about circadian rhythms in the field of fish immunology. In this study, we aimed to analyse the regulation of the diel oscillation of inflammatory cytokine interleukin-1β (il1b) gene expression by core components of the circadian clock in Japanese medaka (Oryzias latipes). The expression of il1b and clock genes (bmal1 and clock1) in medaka acclimated to a 12:12 light (L): dark (D) cycle showed diel rhythm. Additionally, higher expression of il1b was detected in medaka embryo cells (OLHdrR-e3) overexpressing bmal1 and clock1. A significant decrease in il1b expression was observed in OLHdrR-e3 cells after bmal1 knockdown using morpholino oligos. These changes may be mediated by transcriptional regulation via clock proteins, which target the E-box sequence in the cis-element of il1b as identified using luciferase reporter assays. Moreover, LPS stimulation and pathogenic bacterial infection at different zeitgeber time (ZT) under LD12:12 conditions affected the degree of il1b expression, which showed high and low responsiveness to both immuno-stimulations at ZT2 and ZT14, respectively. These results suggested that fish IL-1β exhibited diel oscillation regulated by clock proteins, and its responsiveness to immune-stimulation depends on the time of day.

Propolis: Properties and composition, health benefits and applications in fish nutrition

Propolis is a viscous, waxy, resinous substance that is produced from the exudates of flowers and buds by the action of salivary enzymes of honey bees. Propolis may differ in color (brown, red or green), with color being influenced by the chemical composition and age of the product. Propolis has a special distinctive odor owing to the high concentration of volatile essential oils. It is composed of 5% pollen grains, 10% essential and aromatic oils, 30% wax, 50% resin and balsams, and other minor trace substances. Natural propolis products may be useful for a range of applications in aquaculture systems instead of relying on the application of synthetic compounds to manage many ailments that affect business profitability. It has been reported in several studies that propolis enhances performance, economics, immunity response and disease resistance in different fish species. This present review discusses the functional actions of propolis and the prospects of its use as an antimicrobial, antioxidant, immune-modulatory, antiseptic, antiparasitic, anti-inflammatory and food additive in aquaculture production. In summary, propolis could be a natural supplement that has the potential to improve fish health status and immunity thereby enhancing growth and productivity of the fish industry as well as economic efficiency.

Poly (γ-glutamic acid) based combination of water-insoluble paclitaxel and TLR7 agonist for chemo-immunotherapy

Advanced anti-cancer regimens are being introduced for more effective cancer treatment with improved life expectancy. In this research, immuno-stimulating agent toll-like receptor-7 (TLR-7) agonist-imiquimod and low dose chemotherapeutic agent-paclitaxel were synergized to demonstrate tumor therapy along with anti-tumor memory effect. Both therapeutic agents being water insoluble were dispersed in water with the help of water soluble polymer: poly (γ-glutamic acid) (γ-PGA) using a co-solvent systems leading to formation of micro-dispersions of drugs. Paclitaxel and imiquimod formed crystalline microstructures in the size range of 2-3 μm and were stably dispersed in γ-PGA matrix for more than 6 months. Paclitaxel and combination of paclitaxel and imiquimod had significant tumor killing effect in-vitro on various tumor cell lines, while antigen presenting cells (dendritic cells-DCs) treated with the same concentration of imiquimod along with the combination led to enhanced proliferation (250%). In DCs, enhanced secretion of pro-inflammatory and Th1 cytokines was observed in cells co-treated with paclitaxel and imiquimod dispersed in γ-PGA. When administered by intra-tumoral injection in mouse melanoma tumor model, the treatment with combination exemplified drastic inhibition of tumor growth leading to 70% survival as compared to individual components with 0% survival at day 41. The anti-tumor response generated was also found to have systemic memory response since the vaccinated mice significantly deferred secondary tumor development at distant site 6 weeks after treatment. The relative number and activation status of DCs in-vivo was found to be dramatically increased in case of mice treated with combination. The dramatic inhibition of tumor treated with combination is expected to be mediated by both chemotherapeutic killing of tumor cells followed by uptake of released antigen by the DCs and due to enhanced proliferation and activation of the DCs.

Immunostimulatory effect of artificial feed supplemented with indigenous plants on Clarias gariepinus against Aeromonas hydrophila

The antibacterial activity of methanol extracts of Ficus benghalensis (prop-root) and Leucaena leucocephala (pod seed) was evaluated by measurement of zone of inhibition against pathogenic bacteria, Escherichia coli and Aeromonas hydrophila. Control artificial feed and artificial feed supplemented with 5% powder of F. benghalensis and L. leucocephala were prepared. Juvenile Clarias gariepinus were divided into four groups, acclimatized to laboratory conditions and fed with respective feeds for 20 days prior to the experiment. Immunomodulatory response of supplementary feed was studied by challenging the fish intraperitoneally at weekly intervals, with A. hydrophila. One set of fish, not challenged with A. hydrophila was used as a negative control, to analyze any detrimental effect of supplementary feed, while positive control, comprised of challenged fish fed with non-supplemented feed. Other two groups of fish were challenged with A. hydrophila and fed with respective supplementary feeds. Blood was collected on weekly intervals for four weeks and serum samples were analyzed to evaluate the damage of fish by A. hydrophila through liver function tests. The increase in the levels of Serum glutamic oxaloacetic transaminase (SGOT) and Serum Glutamic pyruvate transaminase (SGPT) in positive control group indicated the damage of liver & kidney. However the levels did not change significantly in fish fed with supplementary feeds when compared to negative control group. Nitric oxide, SOD, ALP and lipid peroxidase indicated lower stress levels in these fish compared to positive control. Fish fed with supplementary feed showed increased lysozyme activity and phagocytic index indicating an increase in non-specific immune response. The immunoglobulin levels of in serum were analyzed by homologous sandwich ELISA, which showed higher antibody production in fish fed with supplementary feed. The current study suggests conclusively, immunostimulatory role of F. benghalensis (prop-roots) and L. leucocephala (pod seed) in C. gariepinus when supplemented in artificial feed.