The anti-cancer activity of a cationic anti-microbial peptide derived from monomers of polyhydroxyalkanoate

Cancer Treatment Using Nanofibers: A Review

Currently, the number of patients with cancer is expanding consistently because of a low quality of life. For this reason, the therapies used to treat cancer have received a lot of consideration from specialists. Numerous anticancer medications have been utilized to treat patients with cancer. However, the immediate utilization of anticancer medicines leads to unpleasant side effects for patients and there are many restrictions to applying these treatments. A number of polymers like cellulose, chitosan, Polyvinyl Alcohol (PVA), Polyacrylonitrile (PAN), peptides and Poly (hydroxy alkanoate) have good properties for the treatment of cancer, but the nanofibers-based target and controlled drug delivery system produced by the co-axial electrospinning technique have extraordinary properties like favorable mechanical characteristics, an excellent release profile, a high surface area, and a high sponginess and are harmless, bio-renewable, biofriendly, highly degradable, and can be produced very conveniently on an industrial scale. Thus, nanofibers produced through coaxial electrospinning can be designed to target specific cancer cells or tissues. By modifying the composition and properties of the nanofibers, researchers can control the release kinetics of the therapeutic agent and enhance its accumulation at the tumor site while minimizing systemic toxicity. The core-shell structure of coaxial electrospun nanofibers allows for a controlled and sustained release of therapeutic agents over time. This controlled release profile can improve the efficacy of cancer treatment by maintaining therapeutic drug concentrations within the tumor microenvironment for an extended period.

Redefining bioactive small molecules from microbial metabolites as revolutionary anticancer agents

Cancer treatment remains a significant challenge due to issues such as acquired resistance to conventional therapies and the occurrence of adverse treatment-related toxicities. In recent years, researchers have turned their attention to the microbial world in search of novel and effective drugs to combat this devastating disease. Microbial derived secondary metabolites have proven to be a valuable source of biologically active compounds, which exhibit diverse functions and have demonstrated potential as treatments for various human diseases. The exploration of these compounds has provided valuable insights into their mechanisms of action against cancer cells. In-depth studies have been conducted on clinically established microbial metabolites, unraveling their anticancer properties, and shedding light on their therapeutic potential. This review aims to comprehensively examine the anticancer mechanisms of these established microbial metabolites. Additionally, it highlights the emerging therapies derived from these metabolites, offering a glimpse into the immense potential they hold for anticancer drug discovery. Furthermore, this review delves into approved treatments and major drug candidates currently undergoing clinical trials, focusing on specific molecular targets. It also addresses the challenges and issues encountered in the field of anticancer drug research and development. It also presents a comprehensive exposition of the contemporary panorama concerning microbial metabolites serving as a reservoir for anticancer agents, thereby illuminating their auspicious prospects and the prospect of forthcoming strides in the domain of cancer therapeutics.

Polyhydroxyalkanoates (PHAs) synthesis and degradation by microbes and applications towards a circular economy

Overusing non-degradable plastics causes a series of environmental issues, inferring a switch to biodegradable plastics. Polyhydroxyalkanoates (PHAs) are promising biodegradable plastics that can be produced by many microbes using various substrates from waste feedstock. However, the cost of PHAs production is higher compared to fossil-based plastics, impeding further industrial production and applications. To provide a guideline for reducing costs, the potential cheap waste feedstock for PHAs production have been summarized in this work. Besides, to increase the competitiveness of PHAs in the mainstream plastics economy, the influencing parameters of PHAs production have been discussed. The PHAs degradation has been reviewed related to the type of bacteria, their metabolic pathways/enzymes, and environmental conditions. Finally, the applications of PHAs in different fields have been presented and discussed to induce comprehension on the practical potentials of PHAs.

Exploiting Polyhydroxyalkanoates for Biomedical Applications

Polyhydroxyalkanoates (PHA) are biodegradable plastic. Numerous bacteria produce PHAs under environmental stress conditions, such as excess carbon-rich organic matter and limitations of other nutritional elements such as potassium, magnesium, oxygen, phosphorus, and nitrogen. In addition to having physicochemical properties similar to fossil-fuel-based plastics, PHAs have unique features that make them ideal for medical devices, such as easy sterilization without damaging the material itself and easy dissolution following use. PHAs can replace traditional plastic materials used in the biomedical sector. PHAs can be used in a variety of biomedical applications, including medical devices, implants, drug delivery devices, wound dressings, artificial ligaments and tendons, and bone grafts. Unlike plastics, PHAs are not manufactured from petroleum products or fossil fuels and are, therefore, environment-friendly. In this review, a recent overview of applications of PHAs with special emphasis on biomedical sectors, including drug delivery, wound healing, tissue engineering, and biocontrols, are discussed.

Novel bacterial taxa in a minimal lignocellulolytic consortium and their potential for lignin and plastics transformation

The understanding and manipulation of microbial communities toward the conversion of lignocellulose and plastics are topics of interest in microbial ecology and biotechnology. In this study, the polymer-degrading capability of a minimal lignocellulolytic microbial consortium (MELMC) was explored by genome-resolved metagenomics. The MELMC was mostly composed (>90%) of three bacterial members (Pseudomonas protegens; Pristimantibacillus lignocellulolyticus gen. nov., sp. nov; and Ochrobactrum gambitense sp. nov) recognized by their high-quality metagenome-assembled genomes (MAGs). Functional annotation of these MAGs revealed that Pr. lignocellulolyticus could be involved in cellulose and xylan deconstruction, whereas Ps. protegens could catabolize lignin-derived chemical compounds. The capacity of the MELMC to transform synthetic plastics was assessed by two strategies: (i) annotation of MAGs against databases containing plastic-transforming enzymes; and (ii) predicting enzymatic activity based on chemical structural similarities between lignin- and plastics-derived chemical compounds, using Simplified Molecular-Input Line-Entry System and Tanimoto coefficients. Enzymes involved in the depolymerization of polyurethane and polybutylene adipate terephthalate were found to be encoded by Ps. protegens, which could catabolize phthalates and terephthalic acid. The axenic culture of Ps. protegens grew on polyhydroxyalkanoate (PHA) nanoparticles and might be a suitable species for the industrial production of PHAs in the context of lignin and plastic upcycling.

Microbial-Derived Polyhydroxyalkanoate-Based Scaffolds for Bone Tissue Engineering: Biosynthesis, Properties, and Perspectives

Polyhydroxyalkanoates (PHAs) are a class of structurally diverse natural biopolyesters, synthesized by various microbes under unbalanced culture conditions. PHAs as biomedical materials have been fabricated in various forms to apply to tissue engineering for the past years due to their excellent biodegradability, inherent biocompatibility, modifiable mechanical properties, and thermo-processability. However, there remain some bottlenecks in terms of PHA production on a large scale, the purification process, mechanical properties, and biodegradability of PHA, which need to be further resolved. Therefore, scientists are making great efforts via synthetic biology and metabolic engineering tools to improve the properties and the product yields of PHA at a lower cost for the development of various PHA-based scaffold fabrication technologies to widen biomedical applications, especially in bone tissue engineering. This review aims to outline the biosynthesis, structures, properties, and the bone tissue engineering applications of PHA scaffolds with different manufacturing technologies. The latest advances will provide an insight into future outlooks in PHA-based scaffolds for bone tissue engineering.

Cell membrane breakage and triggering T cell infiltration are involved in human telomerase reverse transcriptase (hTERT) promoter-driven novel peptide KK-64 for liver cancer gene therapy

Liver cancer is an aggressive malignancy with exhibits both high mortality and morbidity. The current treatment options are associated with several limitations, novel specific anti-cancer drugs are urgently needed to improve liver cancer treatment. In this study, a new peptide KK-64 was designed, and it showed strong cytotoxicity against liver cancer cells. To obtain the tumor targeting property, a plasmid that contains KK-64 DNA fragment and driven by human telomerase reverse transcriptase (hTERT) promoter was constructed. pcTERT-kk-64 plasmid was found to specifically inhibit the viability of liver cancer cells HepG2, induce substantial apoptosis as well as damage to the cell membranes, but had minimal effects toward normal liver HL-7702 cells. Furthermore, pcTERT-kk-64 plasmids was also noted to significantly attenuate migration and invasion of HepG2 cells. The anti-tumor effect of pcTERT-kk-64 plasmid was also observed in H22 cell-bearing mice, and it appeared to cause significant tumor regression, trigger tumor cell apoptosis, and infiltrate cytotoxicity T cells to the tumor tissues after plasmids injection. Thus, pcTERT-kk-64 plasmids showed both strong cytotoxicity and tumor selectivity in vitro and in tumor-bearing mice in liver cancer models.

Polyhydroxyalkanoates, bacterially synthesized polymers, as a source of chemical compounds for the synthesis of advanced materials and bioactive molecules

Research into polyhydroxyalkanoates (PHAs) is growing exponentially. These bacterially derived polyesters offer a spectrum of possible applications, such as in manufacturing of daily-use objects, production of medical devices and implantable objects, or as synthons in chemical and pharmaceutical industries. Thanks to their broad physicochemical features, PHAs can be seen as polymers of the future, which can replace traditional petrochemical equivalents. As they are synthesized by bacteria through fermentation processes, these polyesters can be obtained from virtually any carbon source in a sustainable manner. Characterized by biodegradability and biocompatibility, they are used in many industries, ranging from production of everyday objects to medical applications. Furthermore, as they are built from bioactive monomers, namely (R)-3-hydroxyacids, they provide a platform for the synthesis of advanced chemical compounds. In this mini review, the reader will be acquainted with recent studies conducted at the Jerzy Haber Institute of Catalysis and Surface Chemistry of the Polish Academy of Sciences in collaboration with other groups that have contributed to the development of PHA-based medical materials, bioactive molecules and novel green solvents derived from PHA monomers.Key points• Polyhydroxyalkanoates are emerging polymers for biomedical applications• Polyhydroxyalkanoates can be modified easily to provide novel materials• (R)-3-Hydroxyacids are good synthons for bioactive substances and green solvents.

Polyhydroxyalkanoate/Antifungal Polyene Formulations with Monomeric Hydroxyalkanoic Acids for Improved Antifungal Efficiency

Novel biodegradable and biocompatible formulations of "old" but "gold" drugs such as nystatin (Nys) and amphotericin B (AmB) were made using a biopolymer as a matrix. Medium chain length polyhydroxyalkanoates (mcl-PHA) were used to formulate both polyenes (Nys and AmB) in the form of films (~50 µm). Thermal properties and stability of the materials were not significantly altered by the incorporation of polyenes in mcl-PHA, but polyene containing materials were more hydrophobic. These formulations were tested in vitro against a panel of pathogenic fungi and for antibiofilm properties. The films containing 0.1 to 2 weight % polyenes showed good activity and sustained polyene release for up to 4 days. A PHA monomer, namely 3-hydroxydecanoic acid (C10-OH), was added to the films to achieve an enhanced synergistic effect with polyenes against fungal growth. Mcl-PHA based polyene formulations showed excellent growth inhibitory activity against both Candida yeasts (C. albicans ATCC 1023, C. albicans SC5314 (ATCC MYA-2876), C. parapsilosis ATCC 22019) and filamentous fungi (Aspergillus fumigatus ATCC 13073; Trichophyton mentagrophytes ATCC 9533, Microsporum gypseum ATCC 24102). All antifungal PHA film preparations prevented the formation of a C. albicans biofilm, while they were not efficient in eradication of mature biofilms, rendering them suitable for the transdermal application or as coatings of implants.

Engineering the permeability of Halomonas bluephagenesis enhanced its chassis properties

Bacterial outer membrane (OM), an asymmetric lipid bilayer functioning as a self-protective barrier with reduced permeability for Gram-negative bacteria, yet wasting nutrients and energy to synthesize, has not been studied for its effect on bioproduction. Here we construct several OM-defected halophile Halomonas bluephagenesis strains to investigate the effects of OM on bioproduction. We achieve enhanced chassis properties of H. bluephagenesis based on positive cellular properties among several OM-defected strains. The OM-defected H. bluephagenesis WZY09 demonstrates better adaptation to lower salinity, increasing 28%, 30% and 12% on dry cell mass (DCM), poly(3-hydroxybutyrate) (PHB) accumulation and glucose to PHB conversion rate, respectively, including enlarged cell sizes and 21-folds reduced endotoxin. Interestingly, a poly(3-hydroxybutyrate-co-21mol%4-hydroxybutyrate) (P(3HB-co-21mol%4HB)) is produced by H. bluephagenesis WZY09 derivate WZY249, increasing 60% and 260% on polyhydroxyalkanoate (PHA) production and 4HB content, respectively. Furthermore, increased electroporation efficiency, more sensitive isopropyl β-D-1-thio-galactopyranoside (IPTG) induction, better oxygen uptake, enhanced antibiotics sensitivity and ectoine secretion due to better membrane permeability are observed if OM defected, demonstrating significant OM defection impacts for further metabolic engineering, synthetic biology studies and industrial applications.

Polyhydroxyalkanoates: Trends and advances toward biotechnological applications

Plastics are an integral part of most of the daily requirements. Indiscriminate usage and disposal have led to the accumulation of massive quantities of waste. Their non-biodegradable nature makes it increasingly difficult to manage and dispose them. To counter this impending disaster, biodegradable polymers, especially polyhydroxy-alkanoates (PHAs), have been envisaged as potential alternatives. Owing to their unique physicochemical characteristics, PHAs are gaining importance for versatile applications in the agricultural and medical sectors. Applications in the medical sector are more promising because of their commercial viability and sustainability. Despite such potential, their production and commercialization are significant challenges. The major limitations are their poor mechanical strength, production in small quantities, costly feed, and lack of facilities for industrial production. This article provides an overview of the contemporary progress in the field, to attract researchers and stakeholders to further exploit these renewable resources to produce biodegradable plastics on a commercial scale.

Palmitoylation of Membrane-Penetrating Magainin Derivatives Reinforces Necroptosis in A549 Cells Dependent on Peptide Conformational Propensities

Anticancer lipopeptides (ACLPs) are considered promising alternatives to combat resistant cancer cells, but the influence of peptide conformational propensity alone on their selectivity and mechanism remains obscure. In this study, we developed N-palmitoylated MK5E (P1MK5E) and MEK5 (P1MEK5) that have the same composition of 23 residues undergoing the pH-dependent structural alterations but differ in the conformational tendency of their amino acid composites. Nonlipidated peptides were readily accumulated in the A549 cell nucleus by the direct membrane translocation and the heparan sulfate-mediated endocytosis than the lipid-raft-dependent pathway. The increased hydrophobicity favored the amino acid-position-dependent folding of P1MK5E and P1MEK5, respectively, toward the α-helical coiled-coil nanofibrils and amyloidlike β-protofibrils. At the close concentrations (∼7.5 μM) to the toxic effects of doxorubicin (DOX), P1MK5E exhibited (i) an increased anticancer toxicity through a time-dependent S-phase arrest, (ii) enhanced plasma membrane permeability, and (iii) dose-dependent changes in the cell death characteristic features in the A549 cells relative to P1MEK5 that was almost inactive at ∼75 μM. These observations were in accordance with the TNF-α-mediated necroptotic signaling in the c-MYC/PARP1-overexpressed A549 cells exposed to P1MK5E and accompanied by the ultrastructure of plasma membrane protrusions, extensive endoplasmic reticulum (ER) membrane expansion, mitochondrial swelling, and the formation of distinct cytoplasmic vacuolation. The structural results and the bioactivity behaviors, herein, declared the significance of α-helical propensity in the peptide sequence and the nanostructure morphologies of self-assembling ACLPs upon the selectivity and enhanced anticancer effectiveness, which notably holds promise in the design and development of efficient therapeutics for cancer.

Docetaxel-Loaded Poly(3HB-co-4HB) Biodegradable Nanoparticles: Impact of Copolymer Composition

Polyhydroxyalkanoate (PHA) copolymers show a relatively higher in vivo degradation rate compared to other PHAs, thus, they receive a great deal of attention for a wide range of medical applications. Nanoparticles (NPs) loaded with poorly water-soluble anticancer drug docetaxel (DCX) were produced using poly(3-hydroxybutyrate-co-4-hydroxybutyrate), P(3HB-co-4HB), copolymers biosynthesised from Cupriavidus malaysiensis USMAA1020 isolated from the Malaysian environment. Three copolymers with different molar proportions of 4-hydroxybutirate (4HB) were used: 16% (PHB16), 30% (PHB30) and 70% (PHB70) 4HB-containing P(3HB-co-4HB). Blank and DCX-loaded nanoparticles were then characterized for their size and size distribution, surface charge, encapsulation efficiency and drug release. Preformulation studies showed that an optimised formulation could be achieved through the emulsification/solvent evaporation method using PHB70 with the addition of 1.0% PVA, as stabilizer and 0.03% VitE-TPGS, as surfactant. DCX-loaded PHB70 nanoparticles (DCX-PHB70) gave the desired particle size distribution in terms of average particle size around 150 nm and narrow particle size distribution (polydispersity index (PDI) below 0.100). The encapsulation efficiency result showed that at 30% w/w drug-to-polymer ratio: DCX- PHB16 NPs were able to encapsulate up to 42% of DCX; DCX-PHB30 NPs encapsulated up to 46% of DCX and DCX-PHB70 NPs encapsulated up to 50% of DCX within the nanoparticle system. Approximately 60% of DCX was released from the DCX-PHB70 NPs within 7 days for 5%, 10% and 20% of drug-to-polymer ratio while for the 30% and 40% drug-to-polymer ratios, an almost complete drug release (98%) after 7 days of incubation was observed.

Recent Advances in Bioplastics: Application and Biodegradation

The success of oil-based plastics and the continued growth of production and utilisation can be attributed to their cost, durability, strength to weight ratio, and eight contributions to the ease of everyday life. However, their mainly single use, durability and recalcitrant nature have led to a substantial increase of plastics as a fraction of municipal solid waste. The need to substitute single use products that are not easy to collect has inspired a lot of research towards finding sustainable replacements for oil-based plastics. In addition, specific physicochemical, biological, and degradation properties of biodegradable polymers have made them attractive materials for biomedical applications. This review summarises the advances in drug delivery systems, specifically design of nanoparticles based on the biodegradable polymers. We also discuss the research performed in the area of biophotonics and challenges and opportunities brought by the design and application of biodegradable polymers in tissue engineering. We then discuss state-of-the-art research in the design and application of biodegradable polymers in packaging and emphasise the advances in smart packaging development. Finally, we provide an overview of the biodegradation of these polymers and composites in managed and unmanaged environments.

Effect of poly(3-hydroxyalkanoates) as natural polymers on mesenchymal stem cells

Mesenchymal stem cells (MSCs) are stromal multipotent stem cells that can differentiate into multiple cell types, including fibroblasts, osteoblasts, chondrocytes, adipocytes, and myoblasts, thus allowing them to contribute to the regeneration of various tissues, especially bone tissue. MSCs are now considered one of the most promising cell types in the field of tissue engineering. Traditional petri dish-based culture of MSCs generate heterogeneity, which leads to inconsistent efficacy of MSC applications. Biodegradable and biocompatible polymers, poly(3-hydroxyalkanoates) (PHAs), are actively used for the manufacture of scaffolds that serve as carriers for MSC growth. The growth and differentiation of MSCs grown on PHA scaffolds depend on the physicochemical properties of the polymers, the 3D and surface microstructure of the scaffolds, and the biological activity of PHAs, which was discovered in a series of investigations. The mechanisms of the biological activity of PHAs in relation to MSCs remain insufficiently studied. We suggest that this effect on MSCs could be associated with the natural properties of bacteria-derived PHAs, especially the most widespread representative poly(3-hydroxybutyrate) (PHB). This biopolymer is present in the bacteria of mammalian microbiota, whereas endogenous poly(3-hydroxybutyrate) is found in mammalian tissues. The possible association of PHA effects on MSCs with various biological functions of poly(3-hydroxybutyrate) in bacteria and eukaryotes, including in humans, is discussed in this paper.

Influence of Chemical Modifications of Polyhydroxyalkanoate-Derived Fatty Acids on Their Antimicrobial Properties

Sugar esters are bioactive compounds derived from renewable resources. They consist of a sugar moiety with attached non-polar part – usually a fatty acid. These compounds find uses in cosmetic, food and pharmaceutical industries as surfactants due to their physicochemical and antimicrobial activities. In this study we have produced fatty acids for sugar ester synthesis from bacterially derived polyesters, namely polyhydroxyalkanoates (PHAs). We have developed methodology to decorate PHA monomers with a fluorinated moiety. With aid of biocatalysis a series of glucose esters was created with unmodified and modified PHA monomers. All synthesised compounds showed moderate antimicrobial activity.

Derivatisation of buforin IIb, a cationic henicosapeptide, to afford its complexation to platinum(ii) resulting in a novel platinum(ii)-buforin IIb conjugate with anti-cancer activity

Herein we report the synthesis of buforin IIb, its novel malonate derivative malBuf and its Pt(ii) complex cis-[Pt(NH3)2(malBuf-2H)]. We decided to harness the cell targeting, cell-penetrating and anti-proliferative effects of buforin IIb to help target a cytotoxic dose of a Pt DNA binding species, {Pt(NH3)2} to cancer cells whilst also delivering a peptide with potent anti-cancer properties. Preliminary in vitro data shows cis-[Pt(NH3)2(malBuf-2H)] to be more cytotoxic against the cisplatin resistant ovarian cancer cell line (A2780cisR) relative to buforin IIb, cisplatin and cis-[Pt(NH3)2(malonate)].

Biosynthesis of 2-aminooctanoic acid and its use to terminally modify a lactoferricin B peptide derivative for improved antimicrobial activity

Terminal modification of peptides is frequently used to improve their hydrophobicity. While N-terminal modification with fatty acids (lipidation) has been reported previously, C-terminal lipidation is limited as it requires the use of linkers. Here we report the use of a biocatalyst for the production of an unnatural fatty amino acid, (S)-2-aminooctanoic acid (2-AOA) with enantiomeric excess > 98% ee and the subsequent use of 2-AOA to modify and improve the activity of an antimicrobial peptide. A transaminase originating from Chromobacterium violaceum was employed with a conversion efficiency 52-80% depending on the ratio of amino group donor to acceptor. 2-AOA is a fatty acid with amino functionality, which allowed direct C- and N-terminal conjugation respectively to an antimicrobial peptide (AMP) derived from lactoferricin B. The antibacterial activity of the modified peptides was improved by up to 16-fold. Furthermore, minimal inhibitory concentrations (MIC) of C-terminally modified peptide were always lower than N-terminally conjugated peptides. The C-terminally modified peptide exhibited MIC values of 25 μg/ml for Escherichia coli, 50 μg/ml for Bacillus subtilis, 100 μg/ml for Salmonella typhimurium, 200 μg/ml for Pseudomonas aeruginosa and 400 μg/ml for Staphylococcus aureus. The C-terminally modified peptide was the only peptide tested that showed complete inhibition of growth of S. aureus.

Biomedical Applications of Polyhydroxyalkanoates

Polyhydroxyalkanoates (PHA) are produced by a large number of microbes under stress conditions such as high carbon (C) availability and limitations of nutrients such as nitrogen, potassium, phosphorus, magnesium, and oxygen. Here, microbes store C as granules of PHAs-energy reservoir. PHAs have properties, which are quite similar to those of synthetic plastics. The unique properties, which make them desirable materials for biomedical applications is their biodegradability, biocompatibility, and non-toxicity. PHAs have been found suitable for various medical applications: biocontrol agents, drug carriers, biodegradable implants, tissue engineering, memory enhancers, and anticancer agents.

Lactose esters: synthesis and biotechnological applications

Biodegradable nonionic sugar esters-based surfactants have been gaining more and more attention in recent years due to their chemical plasticity that enables the various applications of these molecules. In this review, various synthesis methods and biotechnological implications of lactose esters (LEs) uses are considered. Several chemical and enzymatic approaches are described for the synthesis of LEs, together with their applications, i.e. function in detergents formulation and as additives that not only stabilize food products but also protect food from undesired microbial contamination. Further, this article discusses medical applications of LEs in cancer treatment, especially their uses as biosensors, halogenated anticancer drugs, and photosensitizing agents for photodynamic therapy of cancer and photodynamic inactivation of microorganisms.

Differential In Vitro and In Vivo Toxicities of Antimicrobial Peptide Prodrugs for Potential Use in Cystic Fibrosis

There has been considerable interest in the use of antimicrobial peptides (AMPs) as antimicrobial agents for the treatment of many conditions, including cystic fibrosis (CF). The challenging conditions of the CF patient lung require robust AMPs that are active in an environment of high proteolytic activity but that also have low cytotoxicity and immunogenicity. Previously, we developed prodrugs of AMPs that limited the cytotoxic effects of AMP treatment by rendering the antimicrobial activity dependent on the host enzyme neutrophil elastase (NE). However, cytotoxicity remained an issue. Here, we describe the further optimization of the AMP prodrug (pro-AMP) model for CF to produce pro-WMR, a peptide with greatly reduced cytotoxicity (50% inhibitory concentration against CFBE41o- cells, >300 μM) compared to that of the previous group of pro-AMPs. The bactericidal activity of pro-WMR was increased in NE-rich bronchoalveolar lavage (BAL) fluid from CF patients (range, 8.4% ± 6.9% alone to 91.5% ± 5.8% with BAL fluid; P = 0.0004), an activity differential greater than that of previous pro-AMPs. In a murine model of lung delivery, the pro-AMP modification reduced host toxicity, with pro-WMR being less toxic than the active peptide. Previously, host toxicity issues have hampered the clinical application of AMPs. However, the development of application-specific AMPs with modifications that minimize toxicity similar to those described here can significantly advance their potential use in patients. The combination of this prodrug strategy with a highly active AMP has the potential to produce new therapeutics for the challenging conditions of the CF patient lung.

Comb-like temperature-responsive polyhydroxyalkanoate-graft-poly(2-dimethylamino-ethylmethacrylate) for controllable protein adsorption

Polyhydroxyalkanoates (PHA) are a family of diverse biopolyesters produced by many bacteria grown on sustainable bio-resources such as glucose or fatty acids.

Polymeric prodrug combination to exploit the therapeutic potential of antimicrobial peptides against cancer cells

The first targeted anticancer polymeric prodrug candidates of antimicrobial peptides, intended for combination therapy with another polymeric prodrug of an approved antineoplastic agent (doxorubicin) are reported.

Polyhydroxyalkanoate-based 3-hydroxyoctanoic acid and its derivatives as a platform of bioactive compounds

A library of 18 different compounds was synthesized starting from (R)-3-hydroxyoctanoic acid which is derived from the bacterial polymer polyhydroxyalkanoate (PHA). Ten derivatives, including halo and unsaturated methyl and benzyl esters, were synthesized and characterized for the first time. Given that (R)-3-hydroxyalkanoic acids are known to have biological activity, the new compounds were evaluated for antimicrobial activity and in vitro antiproliferative effect with mammalian cell lines. The presence of the carboxylic group was essential for the antimicrobial activity, with minimal inhibitory concentrations against a panel of bacteria (Gram-positive and Gram-negative) and fungi (Candida albicans and Microsporum gypseum) in the range 2.8-7.0 mM and 0.1-6.3 mM, respectively. 3-Halogenated octanoic acids exhibited the ability to inhibit C. albicans hyphae formation. In addition, (R)-3-hydroxyoctanoic and (E)-oct-2-enoic acids inhibited quorum sensing-regulated pyocyanin production in the opportunistic pathogen Pseudomonas aeruginosa PAO1. Generally, derivatives did not inhibit mammalian cell proliferation even at 3-mM concentrations, while only (E)-oct-2-enoic and 3-oxooctanoic acid had IC50 values of 1.7 and 1.6 mM with the human lung fibroblast cell line.

Pseudomonas putida-a versatile host for the production of natural products

The biosynthesis of natural products by heterologous expression of biosynthetic pathways in amenable production strains enables biotechnological access to a variety of valuable compounds by conversion of renewable resources. Pseudomonas putida has emerged as a microbial laboratory work horse, with elaborated techniques for cultivation and genetic manipulation available. Beyond that, this bacterium offers several particular advantages with regard to natural product biosynthesis, notably a versatile intrinsic metabolism with diverse enzymatic capacities as well as an outstanding tolerance to xenobiotics. Therefore, it has been applied for recombinant biosynthesis of several valuable natural products. This review provides an overview of applications of P. putida as a host organism for the recombinant biosynthesis of such natural products, including rhamnolipids, terpenoids, polyketides and non-ribosomal peptides, and other amino acid-derived compounds. The focus is on de novo natural product synthesis from intrinsic building blocks by means of heterologous gene expression and strain engineering. Finally, the future potential of the bacterium as a chassis organism for synthetic microbiology is pointed out.

The chain length of biologically produced (R)-3-hydroxyalkanoic acid affects biological activity and structure of anti-cancer peptides

Conjugation of DP18L peptide with (R)-3-hydroxydecanoic acid, derived from the biopolymer polyhydroxyalkanoate, enhances its anti-cancer activity (O'Connor et al., 2013. Biomaterials 34, 2710-2718). However, it is unknown if other (R)-3-hydroxyalkanoic acids (R3HAs) can enhance peptide activity, if chain length affects enhancement, and what effect R3HAs have on peptide structure. Here we show that the degree of enhancement of peptide (DP18L) anti-cancer activity by R3HAs is carbon chain length dependent. In all but one example the R3HA conjugated peptides were more active against cancer cells than the unconjugated peptides. However, R3HAs with 9 and 10 carbons were most effective at improving DP18L activity. DP18L peptide variant DP17L, missing a hydrophobic amino acid (leucine residue 4) exhibited lower efficacy against MiaPaCa cells. Circular dichroism analysis showed DP17L had a lower alpha helix content and the conjugation of any R3HA ((R)-3-hydroxyhexanoic acid to (R)-3-hydroxydodecanoic acid) to DP17L returned the helix content back to levels of DP18L. However (R)-3-hydroxyhexanoic did not enhance the anti-cancer activity of DP17L and at least 7 carbons were needed in the R3HA to enhance activity of D17L. DP17L needs a longer chain R3HA to achieve the same activity as DP18L conjugated to an R3HA. As a first step to assess the synthetic potential of polyhydroxyalkanoate derived R3HAs, (R)-3-hydroxydecanoic acid was synthetically converted to (±)3-chlorodecanoic acid, which when conjugated to DP18L improved its antiproliferative activity against MiaPaCa cells.

Mechanisms of hela cell apoptosis induced by abnormal Savda Munziq total phenolics combined with chemotherapeutic agents

OBJECTIVE

To investigate the effects of abnormal Savda Munziq (ASMq) total phenolics combined with cisplatin and docetaxel on the Hela cell growth.

METHODS

In vivo cultured Hela cells were treated with cisplatin, docetaxel, total phenolics, cisplatin+total phenolics or docetaxel+total phenolics. MTT was performed to assess inhibition of cell proliferation, flow cytometry to detect apoptosis, and semi-quantitative RT-PCR to test for survivin and Bcl-2 expression.

RESULTS

The total phenolics, cisplatin and docetaxel had significant inhibitory and apoptosis-promoting effects on Hela cells (P<0.05), with the early apoptotic rates of 12.8±0.70%, 18.9±3.79% and 15.8±3.8)%; the total phenolics, cisplatin and docetaxel significantly decreased the expression of Bcl-2 and survivin (all P<0.01), especially when used in combination.

CONCLUSION

ASMq total phenolics, combined with cisplatin and docetaxel, could promote the apoptosis of Hela cells possibly through reducing the expression of Bcl-2 and survivin.

Cell system engineering to produce extracellular polyhydroxyalkanoate depolymerase with targeted applications

Novel platforms based on the application of bacterial cell systems as factories for production of new bioproducts open avenues and dramatically expand the catalogue of existing biomaterials. Herein, we designed the strategy based on in vivo production of extracellular Pseudomonas fluorescens GK13 (PhaZGK13) depolymerase to degrade previously biosynthesized polyhydroxyalkanotes (PHAs) or to obtain 3-hydroxyalkanoic acids (HAs). With this aim, extracellular PhaZGK13 was produced in recombinant strains and the optimal conditions for controlled release of HAs and oligomers by growing cells were set up with a particle suspension of (14)C-labelled PHA, being maximal after 24h of incubation. Genetic modification of key factors involved in fatty acids metabolism revealed the influence of an active β-oxidation pathway on the extracellular degradation of PHA and subsequent HAs isolation. The highest HAs production was obtained using Pseudomonas putida KT2442 fadB mutant (0.27mg/mL) due to the reduced ability of this strain to metabolize the degradation products. The system was applied to produce new added value HAs harboring thioester groups in the side chain from the functionalized mcl-PHA, PHACOS. Remarkably, hydrolyzed PHACOS showed greater potential to inhibit Staphylococcus aureus(T) growth when compared to that of degradation products of non functionalized polyhydroxyoctanoate-co-hexanoate P(HO-co-HH).

Conversion of grass biomass into fermentable sugars and its utilization for medium chain length polyhydroxyalkanoate (mcl-PHA) production by Pseudomonas strains

This study investigated the potential of grass biomass as a feedstock for mcl-PHA production. Pretreatments (2% NaOH at 120°C or hot water at 120°C) of perennial ryegrass were employed alone or in combination with sodium chlorite/acetic acid (SC/AA) delignification to evaluate the enzymatic digestibility and subsequent utilization of resultant sugars by Pseudomonas strains. NaOH pretreated sample had better digestibility than raw and hot water treated samples and this hydrolysate supported good growth of all tested strains with limited mcl-PHA (6-17% of cell dry mass (CDM)) accumulation. Digestibility of both untreated and pretreated samples was improved after SC/AA delignification and produced glucose (74-77%) rich hydrolysates. Tested strains accumulated 20-34% of CDM as PHA when these hydrolysates were used as sole carbon and energy source. CDM and PHA yields obtained for these strains when tested with laboratory grade sugars was similar to that achieved with grass derived sugars.