A bioactive peptide analogue for myxoma virus protein with a targeted cytotoxicity for human skin cancer in vitro

Background - Cancer is an international health problem, and the search for effective treatments is still in progress. Peptide therapy is focused on the development of short peptides with strong tumoricidal activity and low toxicity. In this study, we investigated the efficacy of a myxoma virus peptide analogue (RRM-MV) as a candidate for skin cancer therapy. RRM-MV was designed using the Resonant Recognition Model (RRM) and its effect was examined on human skin cancer and normal human skin cells in vitro

Biological Effects of a De Novo Designed Myxoma Virus Peptide Analogue: Evaluation of Cytotoxicity on Tumor Cells

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Key Role of Mfd in the Development of Fluoroquinolone Resistance in Campylobacter jejuni

Campylobacter jejuni is a major food-borne pathogen and a common causative agent of human enterocolitis. Fluoroquinolones are a key class of antibiotics prescribed for clinical treatment of enteric infections including campylobacteriosis, but fluoroquinolone-resistant Campylobacter readily emerges under the antibiotic selection pressure. To understand the mechanisms involved in the development of fluoroquinolone-resistant Campylobacter, we compared the gene expression profiles of C. jejuni in the presence and absence of ciprofloxacin using DNA microarray. Our analysis revealed that multiple genes showed significant changes in expression in the presence of a suprainhibitory concentration of ciprofloxacin. Most importantly, ciprofloxacin induced the expression of mfd, which encodes a transcription-repair coupling factor involved in strand-specific DNA repair. Mutation of the mfd gene resulted in an approximately 100-fold reduction in the rate of spontaneous mutation to ciprofloxacin resistance, while overexpression of mfd elevated the mutation frequency. In addition, loss of mfd in C. jejuni significantly reduced the development of fluoroquinolone-resistant Campylobacter in culture media or chickens treated with fluoroquinolones. These findings indicate that Mfd is important for the development of fluoroquinolone resistance in Campylobacter, reveal a previously unrecognized function of Mfd in promoting mutation frequencies, and identify a potential molecular target for reducing the emergence of fluoroquinolone-resistant Campylobacter

Toward development of novel peptide-based cancer therapeutics:computational design and experimental evaluation

Drug research and discovery are of critical importance in human health care. Computational approaches for drug lead discovery and optimization have proven successful in many recent research programs. These methods have grown in their effectiveness not only because of improved understanding of the basic science, the biological events and molecular interactions that de fi ne a target for therapeutic intervention, but also because of advances in algorithms, representations, and mathematical procedures for studying such processes. Advances in genomics and proteomics and development of new bioinformatics methods contribute greatly to the process of rational drug design, which can be a cost-effective solution to drug discovery. Peptides are emerging as a novel class of drugs for cancer therapy, and many efforts have been made to develop peptide-based pharmacologically active compounds. In this study, we present and discuss three novel bioactive peptide analogues, designed using the Resonant Recognition Model (RRM), and discuss their biological effects on normal and tumor cells from mouse and human origin

Advances in methods for therapeutic peptide discovery, design and development

Drug discovery and development are intense, lengthy and interdisciplinary processes. Traditionally, drugs were discovered by synthesizing compounds in time-consuming multi-step experimental investigations followed by in vitro and in vivo biological screening. Promising candidates were then further studied for their pharmacokinetic properties, metabolism and potential toxicity. Today, the process of drug discovery has been revolutionized due to the advances in genomics, proteomics, and bioinformatics. Efficient technologies such as combinatorial chemistry, high throughput screening (HTS), virtual screening, de novo design and structure-based drug design contribute greatly to drug discovery. Peptides are emerging as a novel class of drugs for cancer therapy, and many efforts have been made to develop peptide-based pharmacologically active compounds. This paper presents a review of current advances and novel approaches in experimental and computational drug discovery and design. We also present a novel bioactive peptide analogue, designed using the Resonant Recognition Model (RRM), and discuss its potential use for cancer therapeutics

The effect of extremely low frequency (ELF) pulsed electromagnetic field (PEMF) on bacteria staphylococcus aureus

Current interest in the application of pulsed electromagnetic fields (PEMF) as alternative therapy for different medical conditions has proven to be successful. There are studies that demonstrate the effectiveness of low frequency PEMF in facilitating wound healing. There are many factors that can affect wound healing and cause improper or impaired tissue repair. Of particular interest are the infected wounds where bacteria or other microorganisms have colonized that cause either a delay in wound healing or deterioration of the wound. In most cases, wounds are typically contaminated by bacteria. In this study, we investigate the application of the applied PEMF on the selected bacterial cultures. In our previous study [1], we presented and discussed the design and development of an extremely low frequency (ELF) PEMF system that produces time varying magnetic field in the range of 0.5 mT to 2.5 mT for a frequency range of 2–500 Hz. Here, we report simulation results of the induced magnetic field distribution and the region of uniformity produced by the system of two pairs of air core Helmholtz coils. We also present the experimental evaluation of varying parametric changes in the applied ELF PEMF on the bacteria Staphylococcus aureus. The selection of this gram-positive bacterium for this study is attributed to the versatile role of these bacteria in infecting wounded tissues. These bacteria are also within easy reach and can be bred at a temperature of 37◦C. Here, the Staphylococcus aureus bacteria in broth were exposed to the ELF PEMF of magnetic flux density, B = 0.5–2.5 mT, frequency (f) range of 2–500 Hz and time of exposure, t = 90 min. This is done in order to compare studied bacterial cultures viability (number of colony-forming units (CFU)). The number of colony-forming units aids in quantifying the experimental result. Fresh bacterial culture is used throughout the experiment. Findings from our investigation have direct implication in determining the optimal characteristics of the applied ELF PEMF for possible treatment of infected tissue and thus, wound healing promotion

Experimental evaluation of antimicrobial effects of the synthetic peptide on pathogenic bacteria

Antibiotics are common anti-infection drugs used these days. However, their excessive applications have led to the rising antibiotic resistance, a serious phenomenon in modern medicine that is regarded as one of the pre-eminent public health concerns of the 21st century. As a result, there is a growing need to find alternative drugs to eradicate the microbial resistance. Antimicrobial peptides (AMPs) are natural defence molecules found in virtually all life forms. They are evolutionary conserved components of the innate immune defence. AMPs utilize different mechanisms of action for killing bacteria, which can vary depending on a type of particular bacterium. Generally, AMPs are broad-spectrum antibiotics that act not only against bacteria but also certain viruses and fungi. A number of studies suggested a possibility of using AMPs as an alternative therapy for treatment of microbial infections

The effects of synthetic azurocidin peptide analogue on staphylococcus aureus bacterium

Antibiotics are commonly used as anti-infection drugs. However, the rising of microbial resistance to antibiotics imposes a major challenge to their widespread applications. Hence, there is a growing need to find alternative drugs to eradicate the microbial resistance arising from the excessive use of antibiotics. Antimicrobial peptides (AMPs) are natural defence molecules found in human body. These AMP are present virtually in all life forms where they act as the first line defence agents against invading pathogens. Published studies suggest the possible use of AMPs as alternative anti-infective drugs. In this study we evaluated the anti-microbial activity of a synthetic Azurocidin peptide analogue and compared its efficacy with the native natural antimicrobial peptide Azurocidin. The Resonant Recognition Model (RRM) was employed here to computationally design a short Azurocidin peptide analogue, Azu-RRM. According to the RRM, this de novo designed peptide analogue will mimic and exhibit the activity of the natural Azurocidin (Azu) protein. Within this study the antimicrobial activity of Azu-RRM was investigated on Staphylococcus aureus (ATCC 25923) bacterium. The results obtained reveal that the synthetic peptide analogue affected the growth of this gram positive bacterium. The findings also showed that the Azu-RRM is exhibiting the anti-microbial effects on the growth of the studied bacteria comparable with the suppressing effects induced by the natural Azu protein

The Akt signaling pathway in skin cancer cell lines treated with RRM-MV, a short peptide analogue of the MT5 protein of myxoma virus

In silico methods can help in identifying drug targets via bioinformatics tools. In our previous studies, a 2.34 kDa short linear peptide analogue to myxoma virus M-T5 protein was computationally designed using the resonant recognition model (RRM). Quantitative and qualitative cell cytotoxicity assays showed that the peptide analogue can induce a dose and time dependent tumoricidal effect on skin cancer cells but not on normal cells. It has been reported that the viral protein (M-T5) binds with p-Akt to regulate Akt signaling in some human cancer types. Hence in this study we investigated the effects induced by the peptide analogue RRM- MV on the Akt pathway in skin cancer and normal cells. Akt expression levels in cells treated with RRM-MV, in the presence or absence of PI3K/Akt inhibitor, were detected in mammalian skin cancer and normal cells using immunoblotting. The results revealed that different endogenous levels of p-Akt were expressed in the human melanoma and carcinoma cells following treatment with RRM-MV. Yet, it did not appear to affect the p-Akt expression in the mouse melanoma cells. Furthermore, RRM-MV treatment did not seem to affect the level of total Akt in any type of cancer cells under the same experimental conditions. Hence, the bioactive peptide RRM-MV appears to be targeting the Akt pathway in some types of skin cancer cells. Elucidating the mechanism of RRM-MV effects on other cellular apoptosis pathways requires further investigation

Irradiation of Escherichia coli by extremely-low frequency (ELF) pulsed electromagnetic fields (PEMF): evaluation of bacterial survival

The effects of extremely low-frequency (ELF) pulsed electromagnetic field (PEMF) emitted by the custom-build exposure chamber on the growth and survival of the bacterium Escherichia coli (E. coli ATCC 25922) have been studied. The viability of E. coli was measured as colony-forming units (CFUs) before and after the exposures at frequencies, f, 2-500 Hz and magnetic flux densities, B, 2.5-5 mT to quantify the effects of applied ELF PEMF on these bacteria. The maximum reduction in bacterial growth was observed with the exposures at 3 Hz and 0.5 mT. The maximum decrease in CFU was recorded for the exposure at 500 Hz and 2.5 mT, which corresponds to a relative decrease of 77.26% in the bacterial growth. Findings from this study have direct implication for determining the optimal characteristics of the applied ELF PEMF for possible treatment of infected tissue and thus, wound healing promotion