A single replacement of histidine to arginine in EGFR-lytic hybrid peptide demonstrates the improved anticancer activity

Short Fragmented Peptides from Pardachirus Marmoratus Exhibit Stronger Anticancer Activities in In Silico Residue Replacement and Analyses

BACKGROUND

Cancer is a worldwide issue. It has been observed that conventional therapies face many problems, such as side effects and drug resistance. Recent research reportedly used marine-derived products to treat various diseases and explored their potential in treating cancers.

OBJECTIVE

This study aims to discover short-length anticancer peptides derived from pardaxin 6 through an in silico approach.

METHODS

Fragmented peptides ranging from 5 to 15 amino acids were derived from the pardaxin 6 parental peptide. These peptides were further replaced with one residue and, along with the original fragmented peptides, were predicted for their SVM scores and physicochemical properties. The top 5 derivative peptides were further examined for their toxicity, hemolytic probability, peptide structures, docking models, and energy scores using various web servers. The trend of in silico analysis outputs across 5 to 15 amino acid fragments was further analyzed.

RESULTS

Results showed that when the amino acids were increased, SVM scores of the original fragmented peptides were also increased. Designed peptides had increased SVM scores, which was aligned with previous studies where the single residue replacement transformed the non-anticancer peptide into an anticancer agent. Moreover, in vitro studies validated that the designed peptides retained or enhanced anticancer effects against different cancer cell lines. Interestingly, a decreasing trend was observed in those fragmented derivative peptides.

CONCLUSION

Single residue replacement in fragmented pardaxin 6 was found to produce stronger anticancer agents through in silico predictions. Through bioinformatics tools, fragmented peptides improved the efficiency of marine-derived drugs with higher efficacy and lower hemolytic effects in treating cancers.

Chemical Strategies towards the Development of Effective Anticancer Peptides

Cancer is increasingly recognized as one of the primary causes of death and has become a multifaceted global health issue. Modern medical science has made significant advancements in the diagnosis and therapy of cancer over the past decade. The detrimental side effects, lack of efficacy, and multidrug resistance of conventional cancer therapies have created an urgent need for novel anticancer therapeutics or treatments with low cytotoxicity and drug resistance. The pharmaceutical groups have recognized the crucial role that peptide therapeutic agents can play in addressing unsatisfied healthcare demands and how these become great supplements or even preferable alternatives to biological therapies and small molecules. Anticancer peptides, as a vibrant therapeutic strategy against various cancer cells, have demonstrated incredible anticancer potential due to high specificity and selectivity, low toxicity, and the ability to target the surface of traditional "undruggable" proteins. This review will provide the research progression of anticancer peptides, mainly focusing on the discovery and modifications along with the optimization and application of these peptides in clinical practice.

Design of Highly Fluorinated Peptides for Cell-based 19F NMR

The design of imaging agents with high fluorine content is essential for overcoming the challenges associated with signal detection limits in 19F MRI-based molecular imaging. In addition to perfluorocarbon and fluorinated polymers, fluorinated peptides offer an additional strategy for creating sequence-defined 19F magnetic resonance imaging (MRI) imaging agents with a high fluorine signal. Our previously reported unstructured trifluoroacetyllysine-based peptides possessed good physiochemical properties and could be imaged at high magnetic field strength. However, the low detection limit motivated further improvements in the fluorine content of the peptides as well as removal of nonspecific cellular interactions. This research characterizes several new highly fluorinated synthetic peptides composed of highly fluorinated amino acids. 19F NMR analysis of peptides TB-1 and TB-9 led to highly overlapping, intense fluorine resonances and acceptable aqueous solubility. Flow cytometry analysis and fluorescence microscopy further showed nonspecific binding could be removed in the case of TB-9. As a preliminary experiment toward developing molecular imaging agents, a fluorinated EGFR-targeting peptide (KKKFFKK-βA-YHWYGYTPENVI) and an EGFR-targeting protein complex E1-DD bioconjugated to TB-9 were prepared. Both bioconjugates maintained good 19F NMR performance in aqueous solution. While the E1-DD-based imaging agent will require further engineering, the success of cell-based 19F NMR of the EGFR-targeting peptide in A431 cells supports the potential use of fluorinated peptides for molecular imaging.

Evolutionary analysis of p38 stress-activated kinases in unicellular relatives of animals suggests an ancestral function in osmotic stress

p38 kinases are key elements of the cellular stress response in animals. They mediate the cell response to a multitude of stress stimuli, from osmotic shock to inflammation and oncogenes. However, it is unknown how such diversity of function in stress evolved in this kinase subfamily. Here, we show that the p38 kinase was already present in a common ancestor of animals and fungi. Later, in animals, it diversified into three JNK kinases and four p38 kinases. Moreover, we identified a fifth p38 paralog in fishes and amphibians. Our analysis shows that each p38 paralog has specific amino acid substitutions around the hinge point, a region between the N-terminal and C-terminal protein domains. We showed that this region can be used to distinguish between individual paralogs and predict their specificity. Finally, we showed that the response to hyperosmotic stress in Capsaspora owczarzaki, a close unicellular relative of animals, follows a phosphorylation-dephosphorylation pattern typical of p38 kinases. At the same time, Capsaspora's cells upregulate the expression of GPD1 protein resembling an osmotic stress response in yeasts. Overall, our results show that the ancestral p38 stress pathway originated in the root of opisthokonts, most likely as a cell's reaction to salinity change in the environment. In animals, the pathway became more complex and incorporated more stimuli and downstream targets due to the p38 sequence evolution in the docking and substrate binding sites around the hinge region. This study improves our understanding of p38 evolution and opens new perspectives for p38 research.

The dual interaction of antimicrobial peptides on bacteria and cancer cells; mechanism of action and therapeutic strategies of nanostructures

Microbial infection and cancer are two leading causes of global mortality. Discovering and developing new therapeutics with better specificity having minimal side-effects and no drug resistance are of an immense need. In this regard, cationic antimicrobial peptides (AMP) with dual antimicrobial and anticancer activities are the ultimate choice. For better efficacy and improved stability, the AMPs available for treatment still required to be modified. There are several strategies in which AMPs can be enhanced through, for instance, nano-carrier application with high selectivity and specificity enables researchers to estimate the rate of drug delivery to a particular tissue. In this review we present the biology and modes of action of AMPs for both anticancer and antimicrobial activities as well as some modification strategies to improve the efficacy and selectivity of these AMPs.

Bioactive peptides from food fermentation: A comprehensive review of their sources, bioactivities, applications, and future development

Bioactive peptides (BPs) are specific protein fragments that exert various beneficial effects on human bodies and ultimately influence health, depending on their structural properties and amino acid composition and sequences. By offering promising solutions to solve diverse health issues, the production, characterization, and applications of food-derived BPs have drawn great interest in the current literature and are of particular interest to the food and pharmaceutical industries. The microbial fermentation of protein from various sources is indubitably a novel way to produce BPs with numerous beneficial health effects. Apart from its lower cost as compared to enzymes, the BPs produced from microbial fermentation can be purified without further hydrolysis. Despite these features, current literature shows dearth of information on the BPs produced from food via microbial fermentation. Hence, there is a strong necessity to explore the BPs obtained from food fermentation for the development of commercial nutraceuticals and functional foods. As such, this review focuses on the production of BPs from different food sources, including the extensively studied milk and milk products, with emphasis on microbial fermentation. The structure-activity (antihypertensive, antioxidant, antimicrobial, opiate-like, anti-inflammatory, anticancer/antiproliferative, antithrombotic, hypolipidemic, hypocholesterolemic, and mineral binding) relationship, potential applications, future development, and challenges of BPs obtained from food fermentation are also discussed.

Application of Phage-Displayed Peptides in Tumor Imaging Diagnosis and Targeting Therapy

Phage display is an effective and powerful technique that provides a route to discovery unique peptides targeting to tumor cells. Specifically binding peptides are considered as the valuable target directing molecule fragments with potential efficiency to improve the current tumor clinic, and offer new approaches for tumor prevention, diagnosis and treatment. We focus on the recent advances in the isolation of tumor-targeting peptides by biopanning methods, with particular emphasis on molecular imaging, and pharmaceutical targeting therapy.

Melittin-encapsulating peptide hydrogels for enhanced delivery of impermeable anticancer peptides

Anticancer peptides (ACPs) have gained significant attention in the past few years. Most ACPs only act toward intracellular targets. However, their low membrane penetrability often limits their anticancer efficacy. Here we developed a novel melittin-RADA28 (MR) hydrogel, composed of RADA28 and melittin, through a peptide fusion method in order to promote the membrane permeability of tumor cells with the membrane-disrupting ability of melittin. As a proof of concept, we loaded the MR hydrogel with a therapeutic peptide, KLA (KLAKLAKKLAKLAK), to show the enhanced delivery efficiency of the hydrogel. Our results demonstrated that the formed melittin-RADA28-KLA peptide (MRP) hydrogel has a nanofiber structure, sustained release profile, and attenuated hemolysis effects. Compared with free KLA, the MRP hydrogel markedly increased the cellular accumulation of KLA, produced the highest ratio of the depolarized mitochondrial membrane, and decreased cell viability in vitro. Following peritumoral injection, the MRP hydrogel treatment suppressed CT26 tumor growth by more than 85%, compared to controls. In summary, we provide a facile and efficient strategy to enhance the delivery of impermeable peptides to improve their therapeutic efficiency.

Analogs of Periplanetasin-4 Exhibit Deteriorated Membrane-Targeted Action

Periplanetasin-4 is an antimicrobial peptide with 13 amino acids identified in cockroaches. It has been reported to induce fungal cell death by apoptosis and membrane-targeted action. Analogs were designed by substituting arginine residues to modify the electrostatic and hydrophobic interactions accordingly and explore the effect of periplanetasin-4 through the increase of net charge and the decrease of hydrophobicity. The analogs showed lower activity than periplanetasin-4 against gram-positive and gram-negative bacteria. Similar to periplanetasin-4, the analogs exhibited slight hemolytic activity against human erythrocytes. Membrane studies, including determination of changes in membrane potential and permeability, and fluidity assays, revealed that the analogs disrupt less membrane integrity compared to periplanetasin-4. Likewise, when the analogs were treated to the artificial membrane model, the passage of molecules bigger than FD4 was difficult. In conclusion, arginine substitution could not maintain the membrane disruption ability of periplanetasin-4. The results indicated that the attenuation of hydrophobic interactions with the plasma membrane caused a reduction in the accumulation of the analogs on the membrane before the formation of electrostatic interactions. Our findings will assist in the further development of antimicrobial peptides for clinical use.

Research Progress Evaluating the Function and Mechanism of Anti-Tumor Peptides

Malignant tumors cause a high mortality rate worldwide, and they severely threaten human health and negatively affect the economy. Despite the advancements in tumor-related molecular genetics and effective new processes in anti-tumor drug development, the anti-tumor drugs currently used in clinical practice are inadequate due to their poor efficacy or severe side effects. Therefore, developing new safe and efficient drugs is a top priority for curing cancer. The peptide has become a suitable agent due to its exact molecular weight between whole protein and small molecule, and it has high targeting ability, high penetrability, low immunogenicity, and is convenient to synthesize and easy to modify. Because of these advantages, peptides have excellent prospect for application as anti-tumor agents. This article reviews the recent research progress evaluating anti-tumor peptides and their anti-tumor mechanisms, and may act as a reference for the future development and clinical application of anti-tumor peptides.

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Rational Design of Hybrid Peptides: A Novel Drug Design Approach

Peptides play crucial roles in various physiological and pathological processes. Consequently, the investigation of peptide-based drugs is a highlight in the research and development of new drugs. However, natural peptides are not always ideal choices for clinical application due to their limited number and sometimes cytotoxicity to normal cells. Aiming to gain stronger or specific or novel biological effects and overcome the disadvantages of natural peptides, artificial hybrid peptides have been designed by combining the sequence of two or more different peptides with varied biological functions. Compared to natural peptides, hybrid peptides have shown better therapeutic potentials against bacteria, tumors, and metabolic diseases. In this review, design strategies, structure features and recent development of hybrid peptides are summarized; future directions for the research and development of hybrid peptide drugs are also discussed.

ACPred: A Computational Tool for the Prediction and Analysis of Anticancer Peptides

Anticancer peptides (ACPs) have emerged as a new class of therapeutic agent for cancer treatment due to their lower toxicity as well as greater efficacy, selectivity and specificity when compared to conventional small molecule drugs. However, the experimental identification of ACPs still remains a time-consuming and expensive endeavor. Therefore, it is desirable to develop and improve upon existing computational models for predicting and characterizing ACPs. In this study, we present a bioinformatics tool called the ACPred, which is an interpretable tool for the prediction and characterization of the anticancer activities of peptides. ACPred was developed by utilizing powerful machine learning models (support vector machine and random forest) and various classes of peptide features. It was observed by a jackknife cross-validation test that ACPred can achieve an overall accuracy of 95.61% in identifying ACPs. In addition, analysis revealed the following distinguishing characteristics that ACPs possess: (i) hydrophobic residue enhances the cationic properties of α-helical ACPs resulting in better cell penetration; (ii) the amphipathic nature of the α-helical structure plays a crucial role in its mechanism of cytotoxicity; and (iii) the formation of disulfide bridges on β-sheets is vital for structural maintenance which correlates with its ability to kill cancer cells. Finally, for the convenience of experimental scientists, the ACPred web server was established and made freely available online.

Purification and identification of novel cytotoxic oligopeptides from soft coral Sarcophyton glaucum

Globally, peptide-based anticancer therapies have drawn much attention. Marine organisms are a reservoir of anticancer peptides that await discovery. In this study, we aimed to identify cytotoxic oligopeptides from Sarcophyton glaucum. Peptides were purified from among the S. glaucum hydrolysates produced by alcalase, chymotrypsin, papain, and trypsin, guided by a methylthiazolyldiphenyl-tetrazolium bromide (MTT) assay on the human cervical cancer (HeLa) cell line for cytotoxicity evaluation. Purification techniques adopted were membrane ultrafiltration, gel filtration chromatography, solid phase extraction (SPE), and reversed-phase high-performance liquid chromatography (RP-HPLC). Purified peptides were identified by de novo peptide sequencing. From papain hydrolysate, three peptide sequences were identified: AGAPGG, AERQ, and RDTQ (428.45, 502.53, and 518.53 Da, respectively). Peptides synthesized from these sequences exhibited cytotoxicity on HeLa cells with median effect concentration (EC₅₀) values of 8.6, 4.9, and 5.6 mmol/L, respectively, up to 5.8-fold stronger than the anticancer drug 5-fluorouracil. When tested at their respective EC₅₀, AGAPGG, AERQ, and RDTQ showed only 16%, 25%, and 11% cytotoxicity to non-cancerous Hek293 cells, respectively. In conclusion, AERQ, AGAPGG, and RDTQ are promising candidates for future development as peptide-based anticancer drugs.

Arginine modification of lycosin-I to improve inhibitory activity against cancer cells

Herein, arginine modification rendered Lycosin-I with higher anticancer activity, penetrability, and dissemination ability against solid tumor cells due to the optimized physicochemical properties and high serum stability.

Replacement of quaternary ammonium headgroups by tri-ornithine in cationic lipids for the improvement of gene delivery in vitro and in vivo

Replacement of quaternary ammonium headgroups by tri-ornithine in lipids improved gene delivery in vitro and in vivo with little toxicity.

Tumor detection using magnetosome nanoparticles functionalized with a newly screened EGFR/HER2 targeting peptide

A novel peptide (P75) targeting EGFR and HER2 is successfully screened from a one-bead-one-compound (OBOC) library containing approximately 2 × 10⁵ peptides built with the aid of computational simulation. In vitro and in vivo analyses show that P75 binds to human epithelial growth factor receptor (EGFR) with nanomolar affinity and to epithelial growth factor receptor-2 (HER2) with a lower affinity but comparable to other reported peptides. The peptide is used to modify the surface of magnetosome nanoparticles (NPs) for targeted magnetic resonance imaging (MRI). In vitro and in vivo fluorescence imaging results suggest peptide P75 modified magnetosomes (Mag-P75) specifically bind to MDA-MB-468 and SKBR3 cells as well as xenograft tumors with surprisingly low accumulation in other organs including liver and kidney. In vivo T₂-weighted MR imaging studies of the xenograft tumors from SKBR3 and MDA-MB-468 cells show obviously negative contrast enhancement. The high affinity and specificity of P75 to EGFR and HER2 positive tumors, together with the success of peptide functionalized magnetosome NPs for targeted MRI demonstrate the potential of this peptide being used in the EGFR and HER2 positive tumors diagnosis and therapy.

Novel EGFR-targeted strategy with hybrid peptide against oesophageal squamous cell carcinoma

Epidermal growth factor receptor (EGFR) is a key molecule in the pathophysiology of oesophageal squamous cell carcinoma (OSCC). However, EGFR-targeted agents such as anti-EGFR antibody or tyrosine kinase inhibitors for OSCC have not demonstrated any clinical benefits. Recently, a novel chemotherapeutic agent, EGFR(2R)-lytic hybrid peptide, a composite of EGFR-binding peptide and lytic peptide fragments, has been shown to exhibit a potent anti-tumour effect against cancers that express high EGFR levels. In this study, we investigated the validity of employing EGFR(2R)-lytic hybrid peptide against OSCC cells both in vitro and in vivo. Additionally, the toxicity of this peptide was assessed in mice. We found high EGFR expression levels on the cell surface of OSCC cells, and the EGFR-binding peptide fragment showed high affinity for OSCC cells. A potent cytotoxic effect was induced within 30 minutes by the exposure of OSCC cells to EGFR(2R)-lytic hybrid peptide. Furthermore, EGFR(2R)-lytic hybrid peptide markedly suppressed the tumour growth of OSCC cells in a xenograft model. Moreover, it did not cause any identifiable adverse effects in mice. Taken together, EGFR(2R)-lytic hybrid peptide was shown to be a valid therapeutic agent against OSCC, providing a crucial rationale regarding novel EGFR-targeted therapies against OSCC.

Enhancement of anti-tumor activity of hybrid peptide in conjugation with carboxymethyl dextran via disulfide linkers

To improve the anti-tumor activity of EGFR2R-lytic hybrid peptide, we prepared peptide-modified dextran conjugates with the disulfide bonds between thiolated carboxymethyl dextran (CMD-Cys) and cysteine-conjugated peptide (EGFR2R-lytic-Cys). In vitro release studies showed that the peptide was released from the CMD-s-s-peptide conjugate in a concentration-dependent manner in the presence of glutathione (GSH, 2μM-2mM). The CMD-s-s-peptide conjugate exhibited a similar cytotoxic activity with free peptide alone against human pancreatic cancer BxPC-3 cells in vitro. Furthermore, it was shown that the CMD-s-s-peptide conjugates were highly accumulated in tumor tissue in a mouse xenograft model using BxPC-3 cells, and the anti-tumor activity of the conjugate was more effective than that of the free peptide. In addition, the plasma concentrations of peptide were moderately increased and the elimination half-life of the peptide was prolonged after intravenous injection of CMD-s-s-peptide conjugates. These results demonstrated that the conjugate based on thiolated CMD polymer would be potentially useful carriers for the sustained release of the hybrid peptide in vivo.

Peptide-based cancer therapy: opportunity and challenge

Cancer is one of the leading causes of death worldwide. Conventional cancer therapies mainly focus on mass cell killing without high specificity and often cause severe side effects and toxicities. Peptides are a novel class of anticancer agents that could specifically target cancer cells with lower toxicity to normal tissues, which will offer new opportunities for cancer prevention and treatment. Anticancer peptides face several therapeutic challenges. In this review, we present the sources and mechanisms of anticancer peptides and further discuss modification strategies to improve the anticancer effects of bioactive peptides.

Targeting interleukin-4 receptor alpha by hybrid Peptide for novel biliary tract cancer therapy

It is known that the interleukin-4 receptor α (IL-4R α ) is highly expressed on the surface of various human solid tumors. We previously designed novel IL-4R α -lytic hybrid peptide composed of binding peptide to IL-4R α and cell-lytic peptide and reported that the designed IL-4R α -lytic hybrid peptide exhibited cytotoxic and antitumor activity both in vitro and in vivo against the human pancreatic cancer cells expressing IL-4R α . Here, we evaluated the antitumor activity of the IL-4R α -lytic hybrid peptide as a novel molecular targeted therapy for human biliary tract cancer (BTC). The IL-4R α -lytic hybrid peptide showed cytotoxic activity in six BTC cell lines with a concentration that killed 50% of all cells (IC50) as low as 5  μ M. We also showed that IL-4R α -lytic hybrid peptide in combination with gemcitabine exhibited synergistic cytotoxic activity in vitro. In addition, intravenous administration of IL-4R α -lytic hybrid peptide significantly inhibited tumor growth in a xenograft model of human BTC in vivo. Taken together, these results indicated that the IL-4R α -lytic hybrid peptide is a potent agent that might provide a novel therapy for patients with BTC.

Localization of the anti-cancer peptide EGFR-lytic hybrid peptide in human pancreatic cancer BxPC-3 cells by immunocytochemistry

Cationic lytic-type peptides have been studied for clinical application in various infections and cancers, but their functional cellular mechanisms remain unclear. We generated anti-cancer epithelial growth factor receptor (EGFR)-lytic hybrid peptide, a 32-amino-acid peptide composed of an EGFR-binding sequence and lytic sequence. In this study, we investigated the distribution of EGFR-lytic hybrid peptide in BxPC-3 human pancreatic cancer cells by an immunocytochemical (ICC) method. Distribution of EGFR protein expression was unchanged after treatment with EGFR-lytic peptide compared with non-treated cells. In confocal laser scanning microscopy, immunostaining of EGFR-lytic peptide was observed in the cytoplasm, mostly in the form of granules. Some staining was also localized on the mitochondrial membrane. At the ultrastructure level, cells treated with EGFR-lytic peptide had a low electron density, disappearance of microvilli, and swollen mitochondria. Fragments of cell membrane were also observed in the proximity of the membrane. In immunoelectron microscopy, EGFR-lytic peptide was observed in the cell membrane and cytoplasm. A number of granules were considered swollen mitochondria. Activation of the caspase pathway as a result of mitochondrial dysfunction was also examined to determine the cytotoxic activity of EGFR-lytic peptide; however, no effect on cell death after EGFR-lytic treatment was observed, and moreover, apoptosis was not found to play a critical role in the cell death mechanism. These results suggest that EGFR-lytic peptide is localized on cell and mitochondrial membranes, with disintegration of the cell membrane contributing mainly to cell death.

Targeting EGFR for treatment of glioblastoma: molecular basis to overcome resistance

Glioblastoma (glioblastoma multiforme; GBM; WHO Grade IV) accounts for the majority of primary malignant brain tumors in adults. Amplification and mutation of the epidermal growth factor receptor (EGFR) gene represent signature genetic abnormalities encountered in GBM. A range of potential therapies that target EGFR or its mutant constitutively active form, ΔEGFR, including tyrosine kinase inhibitors (TKIs), monoclonal antibodies, vaccines, and RNA-based agents, are currently in development or in clinical trials for the treatment of GBM. Data from experimental studies evaluating these therapies have been very promising; however, their efficacy in the clinic has so far been limited by both upfront and acquired drug resistance. This review discusses the current status of anti-EGFR agents and the recurrent problem of resistance to these agents that strongly indicates that a multiple target approach will provide a more favorable future for these types of targeted therapies in GBM.

The effects of dietary supplementation with Agaricales mushrooms and other medicinal fungi on breast cancer: evidence-based medicine

Breast cancer is the most prevalent cancer in women. The most frequent therapeutic approaches for the treatment of this disease are chemotherapy, radiotherapy, hormone therapy, and surgery. Conventional pharmacological treatments cause many harmful side effects in patients. To improve the quality of life of breast cancer patients, researchers have sought alternative adjuvant treatment strategies. To assess the effects of fungi and other basidiomycetes Agaricales on the co-adjuvant treatment of breast cancer, we conducted a literary review of the available scientific evidence. We selected articles published in refereed journals from 1990 to 2011 in Medline, Lilacs, CAPES, Scielo, and Pubmed. Articles written in English, Spanish, and Portuguese were reviewed. We used the following descriptors: Agaricales, medicinal mushroom/fungus, breast cancer, dietary supplementation, synonyms, and related terms. The pharmacological effects of nutritional and medicinal mushrooms have been reported in several experimental clinical studies and have shown promising results in the adjuvant treatment of breast cancer. Adjuvant treatment with mushrooms is associated with improvements in the immunological and hematologic parameters of breast cancer, as well as in the quality of life of these patients. Randomized clinical studies are needed to elucidate the possible mechanisms of action and clinical benefits of these fungi with respect to survival time, disease progression, and metastasis in breast cancer.