Antimicrobial peptide FF/CAP18 induces apoptotic cell death in HCT116 colon cancer cells via changes in the metabolic profile

Investigation of cytotoxic effect and action mechanism of a synthetic peptide derivative of rabbit cathelicidin against MDA-MB-231 breast cancer cell line

Antimicrobial peptides (AMPs) have sparked significant interest as potential anti-cancer agents, thereby becoming a focal point in pursuing novel cancer-fighting strategies. These peptides possess distinctive properties, underscoring the importance of developing more potent and selectively targeted versions with diverse mechanisms of action against human cancer cells. Such advancements would offer notable advantages compared to existing cancer therapies. This research aimed to examine the toxicity and selectivity of the nrCap18 peptide in both cancer and normal cell lines. Furthermore, the rate of cellular death was assessed using apoptosis and acridine orange/ethidium bromide (AO/EB) double staining at three distinct incubation times. Additionally, the impact of this peptide on the cancer cell cycle and migration was evaluated, and ultimately, the expression of cyclin-dependent kinase 4/6 (CDK4/6) genes was investigated. The results obtained from the study demonstrated significant toxicity and selectivity in cancer cells compared to normal cells. Moreover, a strong progressive increase in cell death was observed over time. Furthermore, the peptide exhibited the ability to halt the progression of cancer cells in the G1 phase of the cell cycle and impede their migration by suppressing the expression of CDK4/6 genes.

Pan-cancer analysis of 60S Ribosomal Protein L7-Like 1 (RPL7L1) and validation in liver hepatocellular carcinoma

BACKGROUND AND AIMS

There is an association between cancer and increased ribosome biogenesis. At present, the RPL7L1 (60S Ribosomal Protein L7-Like 1) were less reported by literature search. Study reports that RPL7L1 is associated with mouse embryonic and skeletal muscle. The study of RPL7L1 on tumors has not been reported.

METHODS

Our team downloaded the pan-cancer dataset that is uniformly normalized from the UCSC database (N=19131). Our study examined the relationship between RPL7L1 expression level and clinical prognosis with methylation, anti-tumour immunity, functional states, MSI, TMB, DNSss, LOH and chemotherapeutic responses in 43 cancer types and subtypes.

RESULTS AND CONCLUSIONS

RPL7L1 was overexpressed in nine tumor types. Gene mutation, tumor microenvironment and methylation modification of RPL7L1 plays a key role in patient prognosis. And the high expression of RPL7L1 was associated with TMB, MSI, LOH especially LIHC and HNSC. We experimentally verified that genes can promote the proliferation and migration of tumor cells. Our study suggested that RPL7L1 biomarker can be used for treating cancer, detecting it, and predicting its prognosis.

Application Value of Antimicrobial Peptides in Gastrointestinal Tumors

Gastrointestinal cancer is a common clinical malignant tumor disease that seriously endangers human health and lacks effective treatment methods. As part of the innate immune defense of many organisms, antimicrobial peptides not only have broad-spectrum antibacterial activity but also can specifically kill tumor cells. The positive charge of antimicrobial peptides under neutral conditions determines their high selectivity to tumor cells. In addition, antimicrobial peptides also have unique anticancer mechanisms, such as inducing apoptosis, autophagy, cell cycle arrest, membrane destruction, and inhibition of metastasis, which highlights the low drug resistance and high specificity of antimicrobial peptides. In this review, we summarize the related studies on antimicrobial peptides in the treatment of digestive tract tumors, mainly oral cancer, esophageal cancer, gastric cancer, liver cancer, pancreatic cancer, and colorectal cancer. This paper describes the therapeutic advantages of antimicrobial peptides due to their unique anticancer mechanisms. The length, net charge, and secondary structure of antimicrobial peptides can be modified by design or modification to further enhance their anticancer effects. In summary, as an emerging cancer treatment drug, antimicrobial peptides need to be further studied to realize their application in gastrointestinal cancer diseases.

Cancer Wars: Revenge of the AMPs (Antimicrobial Peptides), a New Strategy against Colorectal Cancer

Cancer is a multifaceted health issue that affects people globally and it is considered one of the leading causes of death with a high percentage of victims worldwide. In recent years, research studies have uncovered great advances in cancer diagnosis and treatment. But, there are still major drawbacks of the conventional therapies used including severe side effects, toxicity, and drug resistance. That is why it is critical to develop new drugs with advantages like low cytotoxicity and no treatment resistance to the cancer cells. Antimicrobial peptides (AMPs) have recently attracted attention as a novel therapeutic strategy for the treatment of various cancers, targeting tumor cells with less toxicity to normal tissues. The aim of the study was to discover alternate treatments that do not lead to cancer resistance and have fewer side effects. Here, we report the effects induced by several AMPs, Melittin, Cecropin A, and a Cecropin A-Melittin hybrid, against two human colorectal cancer-derived spheroids. To study the effects of the peptides, cell viability was investigated using MTT, LDH, and ATP assays. Furthermore, cellular senescence and cell cycle were investigated. We found that using different concentrations of these peptides affected the spheroids, their structure being highly compromised by reducing cell viability, and the increase in ATP and LDH levels. Also, the cells are arrested in the G2/M phase leading to an increase in senescent cells. We show that Melittin and the hybrid are most effective against the 3D colorectal cancer cells compared to Cecropin A.

Developmental and homeostatic signaling transmitted by the G-protein coupled receptor FPR2

Formyl peptide receptor 2 (FPR2) and its mouse counterpart Fpr2 are the members of the G protein-coupled receptor (GPCR) family. FPR2 is the only member of the FPRs that interacts with ligands from different sources. FPR2 is expressed in myeloid cells as well as epithelial cells, endothelial cells, neurons, and hepatocytes. During the past years, some unusual properties of FPR2 have attracted intense attention because FPR2 appears to possess dual functions by activating or inhibiting intracellular signal pathways based on the nature, concentration of the ligands, and the temporal and spatial settings of the microenvironment in vivo, the cell types it interacts with. Therefore, FPR2 controls an abundant array of developmental and homeostatic signaling cascades, in addition to its "classical" capacity to mediate the migration of hematopoietic and non-hematopoietic cells including malignant cells. In this review, we summarize recent development in FPR2 research, particularly in its role in diseases, therefore helping to establish FPR2 as a potential target for therapeutic intervention.

Immunogenic cell death inducer peptides: A new approach for cancer therapy, current status and future perspectives

Immunogenic Cell Death (ICD) is a type of cell death that kills tumor cells by stimulating the adaptive immune response against other tumor cells. ICD depends on the endoplasmic reticulum (ER) stress and the secretion of Damage-Associated Molecular Patterns (DAMP) by the dying tumor cell. DAMPs recruit innate immune cells such as Dendritic Cells (DC), triggering a cancer-specific immune response such as cytotoxic T lymphocytes (CTLs) to eliminate remaining cancer cells. ICD is accompanied by several hallmarks in dying cells, such as surface translocation of ER chaperones, calreticulin (CALR), and extracellular secretion of DAMPs such as high mobility group protein B1 (HMGB1) and adenosine triphosphate (ATP). Therapeutic peptides can kill bacteria and tumor cells thus affecting the immune system. They have high specificity and affinity for their targets, small size, appropriate cell membrane penetration, short half-life, and simple production processes. Peptides are interesting agents for immunomodulation since they may overcome the limitations of other therapeutics. Thus, the development of peptides affecting the TME and active antitumoral immunity has been actively pursued. On the other hand, several peptides have been recently identified to trigger ICD and anti-cancer responses. In the present review, we review previous studies on peptide-induced ICD, their mechanism, their targets, and markers. They include anti-microbial peptides (AMPs), cationic or mitochondrial targeting, checkpoint inhibitors, antiapoptotic inhibitors, and "don't eat me" inhibitor peptides. Also, peptides will be investigated potentially inducing ICD that is divided into ER stressors, ATPase inhibitors, and anti-microbial peptides.

Renovation as innovation: Repurposing human antibacterial peptide LL-37 for cancer therapy

In many organisms, antimicrobial peptides (AMPs) display wide activities in innate host defense against microbial pathogens. Mammalian AMPs include the cathelicidin and defensin families. LL37 is the only one member of the cathelicidin family of host defense peptides expressed in humans. Since its discovery, it has become clear that they have pleiotropic effects. In addition to its antibacterial properties, many studies have shown that LL37 is also involved in a wide variety of biological activities, including tissue repair, inflammatory responses, hemotaxis, and chemokine induction. Moreover, recent studies suggest that LL37 exhibits the intricate and contradictory effects in promoting or inhibiting tumor growth. Indeed, an increasing amount of evidence suggests that human LL37 including its fragments and analogs shows anticancer effects on many kinds of cancer cell lines, although LL37 is also involved in cancer progression. Focusing on recent information, in this review, we explore and summarize how LL37 contributes to anticancer effect as well as discuss the strategies to enhance delivery of this peptide and selectivity for cancer cells.

Novel 1,3-Thiazole Analogues with Potent Activity against Breast Cancer: A Design, Synthesis, In Vitro, and In Silico Study

Breast cancer is the most common cancer in women, responsible for over half a million deaths in 2020. Almost 75% of FDA-approved drugs are mainly nitrogen- and sulfur-containing heterocyclic compounds, implying the importance of such compounds in drug discovery. Among heterocycles, thiazole-based heterocyclic compounds have demonstrated a broad range of pharmacological activities. In the present study, a novel set of 1,3-thiazole derivatives was designed and synthesized based on the coupling of acetophenone derivatives, and phenacyl bromide was substituted as a key reaction step. The activity of synthesized compounds was screened against the proliferation of two breast cancer cell lines (MCF-7 and MDA-MB-231). Almost all compounds exhibited a considerable antiproliferative activity toward the breast cancer cells as compared to staurosporine, with no significant cytotoxicity toward the epithelial cells. Among the synthesized compounds, compound 4 exhibited the most potent antiproliferative activity, with an IC₅₀ of 5.73 and 12.15 µM toward MCF-7 and MDA-MB-231 cells, respectively, compared to staurosporine (IC₅₀ = 6.77 and 7.03 µM, respectively). Exploring the mechanistic insights responsible for the antiproliferative activity of compound 4 revealed that compound 4 possesses a significant inhibitory activity toward the vascular endothelial growth factor receptor-2 (VEGFR-2) with (IC₅₀ = 0.093 µM) compared to Sorafenib (IC₅₀ = 0.059 µM). Further, compound 4 showed the ability to induce programmed cell death by triggering apoptosis and necrosis in MCF-7 cells and to induce cell cycle arrest on MCF-7 cells at the G1 stage while decreasing the cellular population in the G2/M phase. Finally, detailed in silico molecular docking studies affirmed that this class of compounds possesses a considerable binding affinity toward VEGFR2 proteins. Overall, these results indicate that compound 4 could be a promising lead compound for developing potent anti-breast cancer compounds.

Mesenchymal Stem Cell-Derived Antimicrobial Peptides as Potential Anti-Neoplastic Agents: New Insight into Anticancer Mechanisms of Stem Cells and Exosomes

Mesenchymal stem cells (MSCs), as adult multipotent cells, possess considerable regenerative and anti-neoplastic effects, from inducing apoptosis in the cancer cells to reducing multidrug resistance that bring them up as an appropriate alternative for cancer treatment. These cells can alter the behavior of cancer cells, the condition of the tumor microenvironment, and the activity of immune cells that result in tumor regression. It has been observed that during inflammatory conditions, a well-known feature of the tumor microenvironment, the MSCs produce and release some molecules called “antimicrobial peptides (AMPs)” with demonstrated anti-neoplastic effects. These peptides have remarkable targeted anticancer effects by attaching to the negatively charged membrane of neoplastic cells, disrupting the membrane, and interfering with intracellular pathways. Therefore, AMPs could be considered as a part of the wide-ranging anti-neoplastic effects of MSCs. This review focuses on the possible anti-neoplastic effects of MSCs-derived AMPs and their mechanisms. It also discusses preconditioning approaches and using exosomes to enhance AMP production and delivery from MSCs to cancer cells. Besides, the clinical administration of MSCs-derived AMPs, along with their challenges in clinical practice, were debated.

Anticancer activity of chicken cathelicidin peptides against different types of cancer

BACKGROUND

This study served as the pioneer in studying the anti-cancer role of chicken cathelicidin peptides.

METHODS AND RESULTS

Chicken cathelicidins were used as anticancer agent against the breast cancer cell line (MCF-7) and human colon cancer cell line (HCT116). In addition, the mechanism of action of the interaction of cationic peptides with breast cancer cell line MCF-7 was also investigated. An in vivo investigation was also achieved to evaluate the role of chicken cathelicidin in Ehrlich ascites cell (EAC) suppression as a tumor model after subcutaneous implantation in mice. It was found during the study that exposure of cell lines to 40 µg/ml of chicken cathelicidin for 72 h reduced cell lines growth rate by 90-95%. These peptides demonstrated down-regulation of (cyclin A1 and cyclin D genes) of MCF-7 cells. The study showed that two- and three-fold expression of both of caspase-3 and - 7 genes in untreated MCF-7 cells compared to treated MCF-7 cells with chicken cathelicidin peptides. Our data showed that chicken (CATH-1) enhance releasing of TNFα, INF-γ and upregulation of granzyme K in treated mice groups, in parallel, the tumor size and volume was reduced in the treated EAC-bearing groups. Tumor of mice groups treated with chicken cathelicidin displayed high area of necrosis compared to untreated EAC-bearing mice. Based on histological analysis and immunohistochemical staining revealed that the tumor section in Ehrlich solid tumor exhibited a strong Bcl2 expression in untreated control compared to mice treated with 10 & 20 µg of cathelicidin. Interestingly, low expression of Bcl2 were observed in mice taken 40 µg/mL of CATH-1.

CONCLUSIONS

This study drive intention in treatment of cancer through the efficacy of anticancer efficacy of chicken cathelicidin peptides.

Clinical Applications and Anticancer Effects of Antimicrobial Peptides: From Bench to Bedside

Cancer is a multifaceted global health issue and one of the leading causes of death worldwide. In recent years, medical science has achieved great advances in the diagnosis and treatment of cancer. Despite the numerous advantages of conventional cancer therapies, there are major drawbacks including severe side effects, toxicities, and drug resistance. Therefore, the urgency of developing new drugs with low cytotoxicity and treatment resistance is increasing. Antimicrobial peptides (AMPs) have attracted attention as a novel therapeutic strategy for the treatment of various cancers, targeting tumor cells with less toxicity to normal tissues. In this review, we present the structure, biological function, and underlying mechanisms of AMPs. The recent experimental studies and clinical trials on anticancer peptides in different cancer types as well as the challenges of their clinical application have also been discussed.

Antimicrobial peptides: mechanism of action, activity and clinical potential

The management of bacterial infections is becoming a major clinical challenge due to the rapid evolution of antibiotic resistant bacteria. As an excellent candidate to overcome antibiotic resistance, antimicrobial peptides (AMPs) that are produced from the synthetic and natural sources demonstrate a broad-spectrum antimicrobial activity with the high specificity and low toxicity. These peptides possess distinctive structures and functions by employing sophisticated mechanisms of action. This comprehensive review provides a broad overview of AMPs from the origin, structural characteristics, mechanisms of action, biological activities to clinical applications. We finally discuss the strategies to optimize and develop AMP-based treatment as the potential antimicrobial and anticancer therapeutics.

New functionalized 6-thienylpyrimidine-5-carbonitriles as antiproliferative agents against human breast cancer cells

6-Thienylpyrimidine-5-carbonitrile derivatives were synthesized and screened for their in vitro antiproliferative activities against two human breast cancer cell lines in comparison to 5-fluorouracil as a reference. Compounds 2, 3a-c, and 6b evolved as the most active congeners against both cell lines, while others showed selectivity for only one cell line. Compound 2 exerted its effect through inhibition of the epidermal growth factor receptor (EGFR), while 6b showed less aromatase inhibitory activity than letrozole. The rest of the tested compounds did not show significant inhibition, and it can be assumed that they exert their antiproliferative activity through different target mechanisms. In addition, caspase-9 protein activation assays, cell cycle analysis using flow cytometry, and annexin V-fluorescein isothiocyanate-propidium iodide (FITC/PI) dual staining assays were performed for the most active compounds. All the tested compounds were found to be potent pyrimidine derivatives able to initiate apoptosis in MCF-7 and MDA-MB-231 cells.

Antimicrobial peptides against colorectal cancer-a focused review

Despite recent advances in the treatment of colorectal cancer (CRC), low patient survival rate due to emergence of drug resistant cancer cells, metastasis and multiple deleterious side effects of chemotherapy, is a cause of public concern globally. To negate these clinical conundrums, search for effective and harmless novel molecular entities for the treatment of CRC is an urgent necessity. Since antimicrobial peptides (AMPs) are part of innate immunity of living beings, it is quite imperative to look for essential attributes of these peptides which may contribute to their effectiveness against carcinogenesis. Once identified, those characteristics can be suitably modified using several synthetic and computational techniques to further enhance their selectivity and pharmacokinetic profiles. Hence, this review analyses scientific reports describing the antiproliferative action of AMPs derived from several sources, particularly focusing on various colon cancer in vitro/in vivo investigations. On perusal of the literature, it appears that AMPs based therapeutics would definitely find special place in CRC therapy in future either alone or as an adjunct to chemotherapy provided some necessary alterations are made in their natural structures to make them more compatible with modern clinical practice. In this context, further in-depth research is warranted in adequate in vivo models.

Targeting Cancer Heterogeneity with Immune Responses Driven by Oncolytic Peptides

Accumulating preclinical and clinical evidence indicates that high degrees of heterogeneity among malignant cells constitute a considerable obstacle to the success of cancer therapy. This calls for the development of approaches that operate - or enable established treatments to operate - despite such intratumoral heterogeneity (ITH). In this context, oncolytic peptides stand out as promising therapeutic tools based on their ability to drive immunogenic cell death associated with robust anticancer immune responses independently of ITH. We review the main molecular and immunological pathways engaged by oncolytic peptides, and discuss potential approaches to combine these agents with modern immunotherapeutics in support of superior tumor-targeting immunity and efficacy in patients with cancer.

BCL-2 Inhibitor Venetoclax Induces Autophagy-Associated Cell Death, Cell Cycle Arrest, and Apoptosis in Human Breast Cancer Cells

Introduction

Venetoclax (VCX) is a selective BCL-2 inhibitor approved for the treatment of leukemia and lymphoma. However, the mechanisms of anti-cancer effect of VCX either as a monotherapy or in combination with other chemotherapeutic agents against breast cancer need investigation.

Methods

Breast cancer cell lines with different molecular subtypes (MDA-MB-231, MCF-7, and SKBR-3) were treated with different concentrations of VCX for indicated time points. The expression of cell proliferative, apoptotic, and autophagy genes was determined by qRT-PCR and Western blot analyses. In addition, the percentage of MDA-MB-231 cells underwent apoptosis, expressed higher oxidative stress levels, and the changes in the cell cycle phases were determined by flow cytometry.

Results

Treatment of human breast cancer cells with increasing concentrations of VCX caused a significant decrease in cells growth and proliferation. This effect was associated with a significant increase in the percentage of apoptotic MDA-MB-231 cells and in the expression of the apoptotic genes, caspase 3, caspase 7, and BAX, with inhibition of anti-apoptotic gene, BCL-2 levels. Induction of apoptosis by VCX treatment induced cell cycle arrest at G0/G1 phase with inhibition of cell proliferator genes, cyclin D1 and E2F1. Furthermore, VCX treatment increased the formation of reactive oxygen species and the expression level of autophagy markers, Beclin 1 and LC3-II. Importantly, these cellular changes by VCX increased the chemo-sensitivity of MDA-MB-231 cells to doxorubicin.

Discussion

The present study explores the molecular mechanisms of VCX-mediated inhibitory effects on the growth and proliferation of TNBC MDA-MB-231 cells through the induction of apoptosis, cell cycle arrest, and autophagy. The study also explores the role of BCL-2 as a novel targeted therapy for breast cancer.

The G-Protein Coupled Formyl Peptide Receptors and Their Role in the Progression of Digestive Tract Cancer

Chronic inflammation is a causative factor of many cancers, although it originally acts as a protective host response to the loss of tissue homeostasis. Many inflammatory conditions predispose susceptible cells, most of which are of epithelial origin, to neoplastic transformation. There is a close correlation between digestive tract (DT) cancer and chronic inflammation, such as esophageal adenocarcinoma associated with Barrett’s esophagus, helicobacter pylori infection as the cause of stomach cancer, hepatitis leading to liver cirrhosis and subsequent cancer, and colon cancer linking to inflammatory bowel diseases and schistosomiasis. A prominent feature of malignant transformation of DT tract epithelial cells is their adoption of somatic gene mutations resulting in abnormal expression of proteins that endow the cells with unlimited proliferation as well as increased motility and invasive capabilities. Many of these events are mediated by Gi-protein coupled chemoattractant receptors (GPCRs) including formyl peptide receptors (FPRs in human, Fprs in mice). In this article, we review the current understanding of FPRs (Fprs) and their function in DT cancer types as well as their potential as therapeutic targets.

Development and validation of a metabolic gene signature for predicting overall survival in patients with colon cancer

The reprogramming of cellular metabolism is a hallmark of tumorigenesis. However, the prognostic value of metabolism-related genes in colon cancer remains unclear. This study aimed to identify a metabolic gene signature to categorize colon cancer patients into high- and low-risk groups and predict prognosis. Samples from the Gene Expression Omnibus database were used as the training cohort, while samples from The Cancer Genome Atlas database were used as the validation cohort. A metabolic gene signature was established to investigate a robust risk stratification for colon cancer. Subsequently, a prognostic nomogram was established combining the metabolism-related risk score and clinicopathological characteristics of patients. A total of 351 differentially expressed metabolism-related genes were identified in colon cancer. After univariate analysis and least absolute shrinkage and selection operator-penalized regression analysis, an eight-gene metabolic signature (MTR, NANS, HADH, IMPA2, AGPAT1, GGT5, CYP2J2, and ASL) was identified to classify patients into high- and low-risk groups. High-risk patients had significantly shorter overall survival than low-risk patients in both the training and validation cohorts. A high-risk score was positively correlated with proximal colon cancer (P = 0.012), BRAF mutation (P = 0.049), and advanced stage (P = 0.027). We established a prognostic nomogram based on metabolism-related gene risk score and clinicopathologic factors. The areas under the curve and calibration curves indicated that the established nomogram showed a good accuracy of prediction. We have established a novel metabolic gene signature that could predict overall survival in colon cancer patients and serve as a biomarker for colon cancer.

Re-engineering Antimicrobial Peptides into Oncolytics Targeting Drug-Resistant Ovarian Cancers

Introduction

Bacteria and cancer cells share a common trait-both possess an electronegative surface that distinguishes them from healthy mammalian counterparts. This opens opportunities to repurpose antimicrobial peptides (AMPs), which are cationic amphiphiles that kill bacteria by disrupting their anionic cell envelope, into anticancer peptides (ACPs). To test this assertion, we investigate the mechanisms by which a pathogen-specific AMP, originally designed to kill bacterial Tuberculosis, potentiates the lytic destruction of drug-resistant cancers and synergistically enhances chemotherapeutic potency.

Materials and Methods

De novo peptide design, paired with cellular assays, elucidate structure-activity relationships (SAR) important to ACP potency and specificity. Using the sequence MAD1, microscopy, spectrophotometry and flow cytometry identify the peptide's anticancer mechanisms, while parallel combinatorial screens define chemotherapeutic synergy in drug-resistant cell lines and patient derived ex vivo tumors.

Results

SAR investigations reveal spatial sequestration of amphiphilic regions increases ACP potency, but at the cost of specificity. Selecting MAD1 as a lead sequence, mechanistic studies identify that the peptide forms pore-like supramolecular assemblies within the plasma and nuclear membranes of cancer cells to potentiate death through lytic and apoptotic mechanisms. This diverse activity enables MAD1 to synergize broadly with chemotherapeutics, displaying remarkable combinatorial efficacy against drug-resistant ovarian carcinoma cells and patient-derived tumor spheroids.

Conclusions

We show that cancer-specific ACPs can be rationally engineered using nature's AMP toolbox as templates. Selecting the antimicrobial peptide MAD1, we demonstrate the potential of this strategy to open a wealth of synthetic biotherapies that offer new, combinatorial opportunities against drug resistant tumors.

Distribution of positively charged amino acid residues in antimicrobial peptide epinecidin-1 is crucial for in vitro glioblastoma cytotoxicity and its underlying mechanisms

Epinecidin-1 (epi) was identified from orange-spotted grouper (Epinephelus coioides) and exhibits diverse biological activities. The aims of this study were to investigate how the distribution of positively charged amino acid residues affects epi-mediated cytotoxicity and to examine the molecular mechanism underlying epi-induced cytotoxicity in U87MG human glioblastoma cells. MTS/PMS and trypan blue exclusion assay were used to measure cell viability. Necrotic cell death was confirmed by detecting cyclophilin A release and propidium iodide incorporation. DNA damage was evaluated by measuring phosphorylated H2AX. Intracellular reactive oxygen species (ROS) were analyzed by flow cytometry using dihydroergotamine. Mitochondrial membrane potential was detected by flow cytometry using tetramethylrhodamine, ethyl ester. Overall, we found that epi caused cytotoxicity in U87MG cells by inducing DNA damage and necrosis through mitochondrial hyperpolarization and subsequent ROS production. The proper folding of epi into an α-helical structure was essential for epi-mediated anti-glioblastoma effects. In addition, NFκB signaling was activated in U87MG cells after exposure to epi. Suppression of NFκB further enhanced epi-induced cytotoxicity, ROS generation and DNA damage, indicating that NFκB may play a protective role in epi-induced cytotoxicity. Our findings may be useful for the design and improvement of antimicrobial peptides with anti-cancer activity.

The Critical Role of the Antimicrobial Peptide LL-37/ CRAMP in Protection of Colon Microbiota Balance, Mucosal Homeostasis, Anti-Inflammatory Responses, and Resistance to Carcinogenesis

Mouse cathelin-related antimicrobial peptide (CRAMP) and its homologue human cathelicidin (LL-37) play active roles in innate immune responses, angiogenesis, and wound healing. In addition, LL-37/CRAMP fends off microbes and protects against infections in the colon, where the epithelium is exposed to myriad of enteric pathogens. It is increasingly recognized that LL-37/CRAMP maintains colon mucosal barrier integrity, shapes the composition of microbiota, and protects the host from tumorigenesis. In this review, we discuss the importance of LL-37/CRAMP in the homeostasis of the host, with novel findings derived from mice deficient in CRAMP that support the proposition for this natural antimicrobial peptide and an immune modulator as a drug lead for therapeutic development.

LL-37 and its analog FF/CAP18 attenuate neutrophil migration in sepsis-induced acute lung injury

INTRODUCTION

Sepsis can result in acute lung injury. LL-37 is a small cationic host defense peptide involved in anti-inflammatory. In the current study, it was hypothesized that antimicrobial peptide LL-37 could play a protective role in attenuating the progression of sepsis-induced acute lung injury.

METHODS

Forty male C57BL/6 mice were induced into sepsis using cecal ligation and puncture, and subsequently administered with recombinant mouse osteopontin. Peptides LL-37, the LL-37 analog (FF/CAP18, called sLL-37), or normal saline was intravenously administered into septic mice for 20 hours. Then, proinflammatory cytokines (IL-6 and IL-1β), acute lung injury markers (alanine aminotransferase [ALT], aspartate aminotransferase [AST], and lactate dehydrogenase [LDH]), the neutrophil infiltration marker (myeloperoxidase [MPO]), and neutrophil infiltration were detected. Furthermore, the neutrophil migration and expression of migration-related factors (focal adhesion kinase [FAK], ERK, and P38) in differentiated HL-60 cells were detected.

RESULTS

Septic mice had upregulated IL-6, IL-1β, ALT, AST, LDH, MPO, p-FAK, p-ERK, and p-P38, infiltrated neutrophils, and migrated neutrophil-like HL-60 cells. In contrast, the administration of peptide LL-37 and sLL-37 inhibited all these changes. Compared with septic mice, it was found that proinflammatory cytokines, lung injury markers, MPO, and infiltrated neutrophils decreased in mice treated with LL-37 and sLL-37. In addition, the migrated neutrophil-like HL-60 cells and activated p-FAK, p-ERK, and p-P38 proteins were suppressed by LL-37 and sLL-37 treatments.

CONCLUSIONS

Peptide LL-37 and its analog sLL-37 attenuated the progression of sepsis-induced acute lung injury by inhibiting neutrophil infiltration and migration through the FAK, ERK, and P38 pathways.

Design and synthesis of some β-carboline derivatives as multi-target anticancer agents

Aim: Some anticancer β-carbolines exhibited dual inhibition of topo-I and KSP. Methodology/Results: Novel β-carbolines were synthesized and screened for their anticancer activity according to the NCI protocol. Five dose assays results indicated that compounds 9, 10, 12, 17 and 20 were potent and non selective anticancer agents; the sulfanyltriazole 12 was the most potent. Compounds 10, 12 and 20 showed dual topo-I and KSP inhibition with compound 12 being the most potent. Active compounds elicited Pre-G1 apoptosis and cell cycle arrest at G2/M phase of melanoma MDA-MB-435 cells. Docking results, in silico physicochemical and absorption, distribution, metabolism, excretion (ADME) properties were appropriate. Conclusion: Compounds 10, 12 and 20 are potent apoptosis-inducing multitarget anticancer agents that act via dual inhibition of topo-I and KSP-ATPase.

Suppressive effect of an analog of the antimicrobial peptide of LL‑37 on colon cancer cells via exosome‑encapsulated miRNAs

Antimicrobial peptides (AMPs) are multifunctional factors with an important role in the innate immune system. Our previous studies revealed that the human cathelicidin LL-37 and its analog, FF/CAP18, limit the proliferation of colon cancer cell lines. In the present study, the exosomes released by HCT116 cells treated with FF/CAP18 were analyzed. After the treatment, exosomes were isolated from the culture supernatant by ultrafiltration and using the miRCURY™ Exosome Isolation Kit. Membrane vesicles 40-100-nm expressing CD63 and CD81 were identified before and after FF/CAP18 treatment. Exosome concentration in the culture supernatant was increased after treatment with FF/CAP18. Exosomes formed in HCT116 cells treated with FF/CAP18 induced growth suppression of the cells in a dose-dependent manner. By contrast, the exosomes formed in non-treated HCT116 cells did not affect cell viability. Microarray analysis of miRNA expression indicated that FF/CAP18 treatment induced increases in the expression of three miRNAs (miR-584-5p, miR-1202 and miR-3162-5p) in both HCT116 cells and exosomes. These results suggest that FF/CAP18 treatment increases exosome formation, and that exosome-encapsulated miRNAs suppress HCT116 cell proliferation. Exosomal miRNAs are considered to be involved in the dissemination of cell signals to control local cellular microenvironments. The present findings suggest that FF/CAP18 regulates cancer growth by modulating cell-to-cell communication. AMPs localize in the cytoplasm of cancer cells and enhance the expression of growth-suppressing miRNAs. These miRNAs are also transported to other cancer cells via exosomes. Therefore, transportation of these miRNAs has the potential to suppress cancer growth. AMPs exert their effects directly by targeting cancer cells and indirectly via exosomes.

How are the expression patterns of gut antimicrobial peptides modulated by human gastrointestinal diseases? A bridge between infectious, inflammatory, and malignant diseases

The human gut barrier is the tissue exposed to the highest load of microorganisms, harbouring 100 trillion bacteria. In addition, the gut's renewal rate outruns that of any other human tissue. Antimicrobial peptides (AMPs) are highly optimized defense molecules in the intestinal barrier optimized to maintain gastrointestinal homeostasis. Alterations in AMPs activity can lead to or result from human gastrointestinal diseases. In this review, unique, conserved, or otherwise regular alterations in the expression patterns of human AMPs across gastrointestinal inflammatory and infectious diseases were analyzed for pattern elucidation. Human gastrointestinal diseases are associated with alterations in gut AMPs' expression patterns in a peptide-specific, disease-specific, and pathogen-specific way, modulating human gastrointestinal functioning. Across diseases, there is a (i) marked reduction in otherwise constitutively expressed AMPs, leading to increased disease susceptibility, and a (ii) significant increase in the expression of inducible AMPs, leading to tissue damage and disease severity. Infections and inflammatory conditions are associated with altered gene expression in the gut, whose patterns may favour cellular metaplasia, mucosal dysfunction, and disease states. Altered expression of AMPs can thus thrive disease severity and evolution since its early stages. Nevertheless, the modulation of AMP expression patterns unveils promising therapeutic targets.

An experimental study on antitumoral effects of KI-21-3, a synthetic fragment of antimicrobial peptide LL-37, on oral squamous cell carcinoma

PURPOSE

The aim of this study was to investigate the oncolytic properties of KI-21-3, a shortened fragment of LL-37, against oral squamous cell carcinoma (OSCC) in an animal model.

MATERIALS AND METHODS

Twelve athymic nude mice were divided into a therapy and a control group of six animals each. In both groups, SCC-4 cells were administered extraorally into the floor of the mouth in order to create an OSCC model. In the study group, KI-21-3 was applied intravenously during the 8th and 9th weeks. The subjects in the control group were injected with phosphate buffered saline solution in the same manner. During an examination period of 12 weeks, weight control was performed twice a week. Tumor growth was further controlled volumetrically via ultrasonography once a week with regular intervals. Following sacrifice, ablated tumoral tissues were immunohistochemically evaluated in order to determine the proliferation and apoptotic properties.

RESULTS

The mean tumor weight in the AMP group was 0.0236 ± 0.023 g, which was 30% lower than the control group with the mean value of 0.01651 ± 0.012 g. In the control group, the approximate number of the proliferating cells per visualized field was fourfold higher compared to the therapy group. Moreover, in the control group, the number of apoptotic cells per visualized field was significantly lower compared to the therapy group.

CONCLUSION

KI-21-3 showed considerable oncolytic properties on SCC-4 carcinoma cells via antiproliferative and caspase-3 apoptotic pathway. Further investigations are necessary to clarify the dose-dependent effects of this agent.

Human antimicrobial peptides and cancer

Antimicrobial peptides (AMPs) have long been a topic of interest for entomologists, biologists, immunologists and clinicians because of these agents' intriguing origins in insects, their ubiquitous expression in many life forms, their capacity to kill a wide range of bacteria, fungi and viruses, their role in innate immunity as microbicidal and immunoregulatory agents that orchestrate cross-talk with the adaptive immune system, and, most recently, their association with cancer. We and others have theorized that surveillance through epithelial cell-derived AMPs functions to keep the natural flora of microorganisms in a steady state in different niches such as the skin, the intestines, and the mouth. More recently, findings related to specific activation pathways of some of these AMPs have led investigators to associate them with pro-tumoral activity; i.e., contributing to a tumorigenic microenvironment. This area is still in its infancy as there are intriguing yet contradictory findings demonstrating that while some AMPs have anti-tumoral activity and are under-expressed in solid tumors, others are overexpressed and pro-tumorigenic. This review will introduce a new paradigm in cancer biology as it relates to AMP activity in neoplasia to address the following questions: Is there evidence that AMPs contribute to tumor promoting microenvironments? Can an anti-AMP strategy be of use in cancer therapy? Do AMPs, expressed in and released from tumors, contribute to compositional shifting of bacteria in cancerous lesions? Can specific AMP expression characteristics be used one day as early warning signs for solid tumors?

PaDef defensin from avocado (Persea americana var. drymifolia) is cytotoxic to K562 chronic myeloid leukemia cells through extrinsic apoptosis

Plant defensins, a group of antimicrobial peptides, show selective cytotoxicity toward cancer cells. However, their mechanisms of action remain poorly understood. Here, we evaluated the cytotoxicity of PaDef defensin from avocado (Persea americana var. drymifolia) on K562 chronic myeloid leukemia cells and analyzed the pathway involved in the induction of cell death. The defensin PaDef was not cytotoxic against human PBMCs; however, it was cytotoxic for K562 cell line (IC₅₀ = 97.3 μg/ml) activating apoptosis at 12 h. PaDef did not affect the mitochondrial membrane potential (ΔΨm), neither the transmembranal potential or the release of intracellular calcium. Also, PaDef induced gene expression of caspase 8 (∼2 fold), TNF-α (∼4 fold) and TNFR1 (∼10 fold). In addition, the activation of caspase 8 was detected at 24 h, whereas caspase 9 activity was not modified, suggesting that the extrinsic apoptosis pathway could be activated. In conclusion, PaDef induces apoptosis on K562 cells, which is related to the activation of caspase 8 and involves the participation of TNF-α, which is a novel property for a plant defensin.

Regulation of inflammation by members of the formyl-peptide receptor family

Inflammation is associated with a variety of diseases. The hallmark of inflammation is leukocyte infiltration at disease sites in response to pathogen- or damage-associated chemotactic molecular patterns (PAMPs and MAMPs), which are recognized by a superfamily of seven transmembrane, Gi-protein-coupled receptors (GPCRs) on cell surface. Chemotactic GPCRs are composed of two major subfamilies: the classical GPCRs and chemokine GPCRs. Formyl-peptide receptors (FPRs) belong to the classical chemotactic GPCR subfamily with unique properties that are increasingly appreciated for their expression on diverse host cell types and the capacity to interact with a plethora of chemotactic PAMPs and MAMPs. Three FPRs have been identified in human: FPR1-FPR3, with putative corresponding mouse counterparts. FPR expression was initially described in myeloid cells but subsequently in many non-hematopoietic cells including cancer cells. Accumulating evidence demonstrates that FPRs possess multiple functions in addition to controlling inflammation, and participate in the processes of many pathophysiologic conditions. They are not only critical mediators of myeloid cell trafficking, but are also implicated in tissue repair, angiogenesis and protection against inflammation-associated tumorigenesis. A series recent discoveries have greatly expanded the scope of FPRs in host defense which uncovered the essential participation of FPRs in step-wise trafficking of myeloid cells including neutrophils and dendritic cells (DCs) in host responses to bacterial infection, tissue injury and wound healing. Also of great interest is the FPRs are exploited by malignant cancer cells for their growth, invasion and metastasis. In this article, we review the current understanding of FPRs concerning their expression in a vast array of cell types, their involvement in guiding leukocyte trafficking in pathophysiological conditions, and their capacity to promote the differentiation of immune cells, their participation in tumor-associated inflammation and cancer progression. The close association of FPRs with human diseases and cancer indicates their potential as targets for the development of therapeutics.

Environmental influences in the etiology of colorectal cancer: the premise of metabolomics

PURPOSE OF REVIEW

In this review we discuss how environmental exposures predominate the etiology of colorectal cancer (CRC). With CRC being a personalized disease influenced by genes and environment, our goal was to explore the role metabolomics can play in identifying exposures, assessing the interplay between co-exposures, and the development of personalized therapeutic interventions.

RECENT FINDINGS

Approximately 10 % of CRC cases can be explained by germ-line mutations, whereas the prevailing majority are caused by an initiating exposure event occurring decades prior to diagnosis. Recent research has shown that dietary metabolites are linked to a procarcinogenic or protective environment in the colon which is modulated by the microbiome. In addition, excessive alcohol has been shown to increase the risk of CRC and is dependent on diet (folate), the response of microbiome, and genetic polymorphisms within the folate and alcohol metabolic pathways. Metabolomics can not only be used to identify this modulation of host metabolism, which could affect the progression of the tumors but also response to targeted therapeutics.

SUMMARY

This review highlights the current understanding of the multifaceted etiology and mechanisms of CRC development but also highlights where the field of metabolomics can contribute to a greater understanding of environmental exposure in CRC.

miR-663a regulates growth of colon cancer cells, after administration of antimicrobial peptides, by targeting CXCR4-p21 pathway

Background

Antimicrobial peptides (AMPs) play important roles in the innate immune system of all life forms and recently have been characterized as multifunctional peptides that have a variety of biological roles such as anticancer agents. However, detailed mechanism of antimicrobial peptides on cancer cells is still largely unknown.

Methods

miRNA array and real-time qPCR were performed to reveal the behavior of miRNA in colon cancer HCT116 cells during the growth suppression induced by the AMPs. Establishment of miR-663a over-expressing HCT116 cells was carried out for the evaluation of growth both in vitro and in vivo. To identify the molecular mechanisms, we used western blotting analysis.

Results

miR-663a is upregulated by administration of the human cathelicidin AMP, LL-37, and its analogue peptide, FF/CAP18, in the colon cancer cell line HCT116. Over-expression of miR-663a caused anti-proliferative effects both in vitro and in vivo. We also provide evidence supporting the view that these effects are attributed to suppression of the expression of the chemokine receptor CXCR4, resulting in the abrogation of phosphorylation of Akt and cell cycle arrest in G2/M via p21 activation.

Conclusions

This study contributes to the understanding of the AMPs’ mediated anti-cancer mechanisms in colon cancer cells and highlights the possibility of using AMPs and miRNAs towards developing future strategies for cancer therapy.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-016-3003-9) contains supplementary material, which is available to authorized users.

The G-protein coupled chemoattractant receptor FPR2 promotes malignant phenotype of human colon cancer cells

The G-protein coupled chemoattractant receptor formylpeptide receptor-2 (FPR2 in human, Fpr2 in mice) is expressed by mouse colon epithelial cells and plays a critical role in mediating mucosal homeostasis and inflammatory responses. However, the biological role of FPR2 in human colon is unclear. Our investigation revealed that a considerable number of human colon cancer cell lines expressed FPR2 and its ligands promoted cell migration and proliferation. Human colon cancer cell lines expressing high levels of FPR2 also formed more rapidly growing tumors in immunocompromised mice as compared with cell lines expressing lower levels of FPR2. Knocking down of FPR2 from colon cancer cell lines highly expressing FPR2 reduced their tumorigenicity. Clinically, FPR2 is more highly expressed in progressive colon cancer, associated with poorer patient prognosis. These results suggest that FPR2 can be high-jacked by colon cancer cells for their growth advantage, thus becoming a potential target for therapeutic development.

A metabolic profile in Ruditapes philippinarum associated with growth-promoting effects of alginate hydrolysates

The aim of this study is to demonstrate the growth-promoting effect of alginate hydrolysates (AHs) on the Manila clam Ruditapes philippinarum, and to verify the physiological change occurring within a living R. philippinarum stimulated by AHs. We show that growth of clams was dramatically promoted by supplementing a diet of the diatom Chaetoceros neogracile with AHs at 4 mg/mL. Furthermore, metabolomics indicates that each state of starvation, food satiation, and sexual maturation have a characteristic pattern. In the groups given AHs in addition to C. neogracile in particular, excess carbohydrate was actively utilized for the development of reproductive tissue. In contrast, it appeared that clams in the groups given C. neogracile only were actively growing, utilizing their adequate carbohydrate resources. Meanwhile, the unfed groups have slowed growth because of the lack of an energy source. Hence, supplementation of AHs in addition to the algal diet may be an inexpensive way to shorten the rearing period of R. philippinarum. Moreover, metabolomics can evaluate the growth condition of R. philippinarum in a comprehensive way, and this approach is crucially important for not only the development of a mass culture method but also for the conservation of the clam resource in the field.

Metabolomics as a Challenging Approach for Medicinal Chemistry and Personalized Medicine

"Omics" sciences have been developed to provide a holistic point of view of biology and to better understand the complexity of an organism as a whole. These systems biology approaches can be examined at different levels, starting from the most fundamental, i.e., the genome, and finishing with the most functional, i.e., the metabolome. Similar to how genomics is applied to the exploration of DNA, metabolomics is the qualitative and quantitative study of metabolites. This emerging field is clearly linked to genomics, transcriptomics, and proteomics. In addition, metabolomics provides a unique and direct vision of the functional outcome of an organism's activities that are required for it to survive, grow, and respond to internal and external stimuli or stress, e.g., pathologies and drugs. The links between metabolic changes, patient phenotype, physiological and/or pathological status, and treatment are now well established and have opened a new area for the application of metabolomics in the drug discovery process and in personalized medicine.

Metabolomic Studies of Oral Biofilm, Oral Cancer, and Beyond

Oral diseases are known to be closely associated with oral biofilm metabolism, while cancer tissue is reported to possess specific metabolism such as the ‘Warburg effect’. Metabolomics might be a useful method for clarifying the whole metabolic systems that operate in oral biofilm and oral cancer, however, technical limitations have hampered such research. Fortunately, metabolomics techniques have developed rapidly in the past decade, which has helped to solve these difficulties. In vivo metabolomic analyses of the oral biofilm have produced various findings. Some of these findings agreed with the in vitro results obtained in conventional metabolic studies using representative oral bacteria, while others differed markedly from them. Metabolomic analyses of oral cancer tissue not only revealed differences between metabolomic profiles of cancer and normal tissue, but have also suggested a specific metabolic system operates in oral cancer tissue. Saliva contains a variety of metabolites, some of which might be associated with oral or systemic disease; therefore, metabolomics analysis of saliva could be useful for identifying disease-specific biomarkers. Metabolomic analyses of the oral biofilm, oral cancer, and saliva could contribute to the development of accurate diagnostic, techniques, safe and effective treatments, and preventive strategies for oral and systemic diseases.

The Human Cathelicidin Antimicrobial Peptide LL-37 and Mimics are Potential Anticancer Drugs

Antimicrobial peptides (AMPs) play a critical role in innate host defense against microbial pathogens in many organisms. The human cathelicidin, LL-37, has a net positive charge and is amphiphilic, and can eliminate pathogenic microbes directly via electrostatic attraction toward negatively charged bacterial membranes. A number of studies have shown that LL-37 participates in various host immune systems, such as inflammatory responses and tissue repair, in addition to its antibacterial properties. Moreover, recent evidence suggests that it is also involved in the regulation of cancer. Indeed, previous studies have suggested that human LL-37 is involved in carcinogenesis via multiple reporters, such as FPR2 (FPRL1), epidermal growth factor receptor, and ERBb2, although LL-37 and its fragments and analogs also show anticancer effects in various cancer cell lines. This discrepancy can be attributed to peptide-based factors, host membrane-based factors, and signal regulation. Here, we describe the association between AMPs and cancer with a focus on anticancer peptide functions and selectivity in an effort to understand potential therapeutic implications.