Bacteriocins as Potential Therapeutic Approaches in the Treatment of Various Cancers: A Review of In Vitro Studies

The Bacteriocins Produced by Lactic Acid Bacteria and the Promising Applications in Promoting Gastrointestinal Health

Bacteriocins produced by lactic acid bacteria (LAB) are promising bioactive peptides. Intriguingly, bacteriocins have health benefits to the host and may be applied safely in the food industry as bio-preservatives or as therapeutic interventions preventing intestinal diseases. In recent years, finding a safe alternative approach to conventional treatments to promote gut health is a scientific hotspot. Therefore, this review aimed to give insight into the promising applications of LAB-bacteriocins in preventing intestinal diseases, such as colonic cancer, Helicobacter pylori infections, multidrug-resistant infection-associated colitis, viral gastroenteritis, inflammatory bowel disease, and obesity disorders. Moreover, we highlighted the recent research on bacteriocins promoting gastrointestinal health. The review also provided insights into the proposed mechanisms, challenges and opportunities, trends and prospects. In addition, a SWOT analysis was conducted on the potential applications. Based on properties, biosafety, and health functions of LAB-bacteriocins, we conclude that the future applications of LAB-bacteriocins are promising in promoting gastrointestinal health. Further in vivo trials are needed to confirm these potential effects of LAB-bacteriocins interventions.

Emerging lactic acid bacteria bacteriocins as anti-cancer and anti-tumor agents for human health

Modern cancer diagnostics and treatment options have greatly improved survival rates; the illness remains a major cause of mortality worldwide. Current treatments for cancer, such as chemotherapy, are not cancer-specific and may cause harm to healthy cells; therefore, it is imperative that new drugs for cancer be developed that are both safe and effective. It has been found that lactic acid bacteria (LAB) have the potential to produce bacteriocins, which could potentially offer a promising alternative for cancer treatment. They have been shown in several studies to be effective against cancer cells while having no effect on healthy cells. More research is needed to fully understand the potential of LAB bacteriocins as anti-cancer medicines, to find the appropriate dose and delivery route, and to conduct clinical trials to evaluate the effectiveness and safety of the products in human patients, as is suggested by this work. Furthermore, LAB bacteriocins may evolve into a significant new class of anti-cancer drugs and food products. Patients with cancer may have a safe and effective alternative treatment option in the form of anti-cancer foods and drugs. Therefore, the aim of this study is to provide an in-depth analysis of the recent breakthroughs and potential future technical advancements of significant bacteriocins that are produced by LAB, how these bacteriocins function, and how these bacteriocins may be utilized as an anti-cancer agent. In addition, the current analysis emphasizes the significant constraints and boundaries that bacteriocins face when they are used as an anti-cancer factor.

Advances in nanobubbles for cancer theranostics: Delivery, imaging and therapy

Maximizing treatment efficacy and forecasting patient prognosis in cancer necessitates the strategic use of targeted therapy, coupled with the prompt precise detection of malignant tumors. Theutilizationof gaseous systems as an adaptable platform for creating nanobubbles (NBs) has garnered significant attention as theranostics, which involve combining contrast chemicals typically used for imaging with pharmaceuticals to diagnose and treattumorssynergistically in apersonalizedmanner for each patient. This review specifically examines the utilization of oxygen NBsplatforms as a theranostic weapon in the field of oncology. We thoroughly examine the key factors that impact the effectiveness of NBs preparations and the consequences of these treatment methods. This review extensively examines recent advancements in composition schemes, advanced developments in pre-clinical phases, and other groundbreaking inventions in the area of NBs. Moreover, this review offers a thorough examination of the optimistic future possibilities, addressing prospective methods for improvement and incorporation into widely accepted therapeutic practices. As we explore the ever-changing field of cancer theranostics, the incorporation of oxygen NBs appears as a promising development, providing new opportunities for precision medicine and marking a revolutionary age in cancer research and therapy.

Bacteriocins in Cancer Treatment: Mechanisms and Clinical Potentials

Cancer poses a severe threat to human health. Although conventional chemotherapy remains a cornerstone of cancer treatment, its significant side effects and the growing issue of drug resistance necessitate the urgent search for more efficient and less toxic anticancer drugs. In recent years, bacteriocins, antimicrobial peptides of microbial origin, have garnered significant attention due to their targeted antitumor activity. This unique activity is mainly attributed to their cationic and amphiphilic nature, which enables bacteriocins to specifically kill tumor cells without harming normal cells. When involving non-membrane-disrupting mechanisms, such as apoptosis induction, cell cycle blockade, and metastasis inhibition, the core mechanism of action is achieved by disrupting cell membranes, which endows bacteriocins with low drug resistance and high selectivity. However, the susceptibility of bacteriocins to hydrolysis and hemolysis in vivo limits their clinical application. To overcome these challenges, structural optimization of bacteriocins or their combination with nanotechnology is proposed for future development. This review aims to study the mechanism of action and current research status of bacteriocins as anticancer treatments, thus providing new insights for their clinical development and application.

Harnessing probiotic foods: managing cancer through gut health

One of the greatest threats to global health is cancer. Probiotic foods have been shown to have therapeutic promise in the management of cancer, even though traditional treatments such as radiation therapy, chemotherapy, and surgery are still essential. The generation of anticarcinogenic compounds, immune system stimulation, and gut microbiota regulation are a few ways that probiotics when taken in sufficient quantities, might help health. The purpose of this review is to examine the therapeutic potential of probiotic foods in the management of cancer. Research suggests that certain strains of probiotics have anticancer effects by preventing the growth of cancer cells, triggering apoptosis, and reducing angiogenesis in new tumors. Probiotics have shown promise in mitigating treatment-related adverse effects, such as diarrhea, mucositis, and immunosuppression caused by chemotherapy, improving the general quality of life for cancer patients. However, there are several factors, such as patient-specific features, cancer subtype, and probiotic strain type and dosage, which affect how effective probiotic therapies are in managing cancer. More research is necessary to find the long-term safety and efficacy characteristics of probiotics as well as to clarify the best ways to incorporate them into current cancer treatment methods.

Graphical abstract

Graphical representation showing the role of probiotic foods in cancer management.

Lactic Acid Bacteria-Derived Postbiotics as Adjunctive Agents in Breast Cancer Treatment to Boost the Antineoplastic Effect of a Conventional Therapeutic Comprising Tamoxifen and a New Drug Candidate: An Aziridine-Hydrazide Hydrazone Derivative

Breast cancer is associated with high mortality and morbidity rates. As about 20-30% of patients exhibiting ER-positive phenotype are resistant to hormonal treatment with the standard drug tamoxifen, finding new therapies is a necessity. Postbiotics, metabolites, and macromolecules isolated from probiotic bacteria cultures have been proven to have sufficient bioactivity to exert prohealth and anticancer effects, making them viable adjunctive agents for the treatment of various neoplasms, including breast cancer. In the current study, postbiotics derived from L. plantarum and L. rhamnosus cultures were assessed on an in vitro breast cancer model as potential adjunctive agents to therapy utilizing tamoxifen and a candidate aziridine-hydrazide hydrazone derivative drug. Cell viability and cell death processes, including apoptosis, were analyzed for neoplastic MCF-7 cells treated with postbiotics and synthetic compounds. Cell cycle progression and proliferation were analyzed by PI-based flow cytometry and Ki-67 immunostaining. Postbiotics decreased viability and triggered apoptosis in MCF-7, modestly affecting the cell cycle and showing a lack of negative impact on normal cell viability. Moreover, they enhanced the cytotoxic effect of tamoxifen and the new candidate drug toward MCF-7, accelerating apoptosis and the inhibition of proliferation. This illustrates postbiotics' potential as natural adjunctive agents supporting anticancer therapy based on synthetic drugs.

Bacteriocins: potentials and prospects in health and agrifood systems

Bacteriocins are highly diverse, abundant, and heterogeneous antimicrobial peptides that are ribosomally synthesized by bacteria and archaea. Since their discovery about a century ago, there has been a growing interest in bacteriocin research and applications. This is mainly due to their high antimicrobial properties, narrow or broad spectrum of activity, specificity, low cytotoxicity, and stability. Though initially used to improve food quality and safety, bacteriocins are now globally exploited for innovative applications in human, animal, and food systems as sustainable alternatives to antibiotics. Bacteriocins have the potential to beneficially modulate microbiota, providing viable microbiome-based solutions for the treatment, management, and non-invasive bio-diagnosis of infectious and non-infectious diseases. The use of bacteriocins holds great promise in the modulation of food microbiomes, antimicrobial food packaging, bio-sanitizers and antibiofilm, pre/post-harvest biocontrol, functional food, growth promotion, and sustainable aquaculture. This can undoubtedly improve food security, safety, and quality globally. This review highlights the current trends in bacteriocin research, especially the increasing research outputs and funding, which we believe may proportionate the soaring global interest in bacteriocins. The use of cutting-edge technologies, such as bioengineering, can further enhance the exploitation of bacteriocins for innovative applications in human, animal, and food systems.

Molecular Dynamic Study on the Structure and Thermal Stability of Mutant Pediocin PA-1 Peptides Engineered with Cysteine Substitutions

Pediocin and analogous bacteriocins, valued for thermal stability, serve as versatile antimicrobials in the food sector. Improving their resilience at high temperatures and deriving derivatives not only benefit food production but also offer broad-spectrum antimicrobial potential in pharmaceuticals, spanning treatments for peptic ulcers, women's health, and novel anticancer agents. The study aims to create mutant peptides capable of establishing a third disulfide bond or enhanced through cysteine substitutions. This involves introducing additional Cys residues into the inherent structure of pediocin PA-1 to facilitate disulfide bond formation. Five mutants (Mut 1-5) were systematically generated with double Cys substitutions and assessed for thermal stability through MD simulations across temperatures (298-394 K). The most robust mutants (Mut 1, Mut 4-5) underwent extended analysis via MD simulations, comparing their structural stability, secondary structure, and surface accessibility to the reference Pediocin PA-1 molecule. This comprehensive assessment aims to understand how Cys substitutions influence disulfide bonds and the overall thermal stability of the mutant peptides. In silico analysis indicated that Mut 1 and Mut 5, along with the reference structure, lose their helical structure and one natural disulfide bond at high temperatures, and may impacting antimicrobial activity. Conversely, Mut 4 retained its helical structure and exhibited thermal stability similar to Pediocin PA-1. Pending further experimental validation, this study implies Mut 4 may have high stability and exceptional resistance to high temperatures, potentially serving as an effective antimicrobial alternative.

Therapeutic Management of Malignant Wounds: An Update

OPINION STATEMENT

Malignant fungating wounds (MFW) are severe skin conditions generating tremendous distress in oncological patients with advanced cancer stages because of pain, malodor, exudation, pruritus, inflammation, edema, and bleeding. The classical therapeutic approaches such as surgery, opioids, antimicrobials, and application of different wound dressings are failing in handling pain, odor, and infection control, thus urgently requiring the development of alternative strategies. The aim of this review was to provide an update on the current therapeutic strategies and the perspectives on developing novel alternatives for better malignant wound management. The last decade screened literature evidenced an increasing interest in developing natural treatment alternatives based on beehive, plant extracts, pure vegetal compounds, and bacteriocins. Promising therapeutics can also be envisaged by involving nanotechnology due to either intrinsic biological activities or drug delivery properties of nanomaterials. Despite recent progress in the field of malignant wound care, the literature is still mainly based on in vitro and in vivo studies on small animal models, while the case reports and clinical trials (less than 10 and only one providing public results) remain scarce. Some innovative treatment approaches are used in clinical practice without prior extensive testing in fungating wound patients. Extensive research is urgently needed to fill this knowledge gap and translate the identified promising therapeutic approaches to more advanced testing stages toward creating multidimensional wound care strategies.

Bioprospecting the Skin Microbiome: Advances in Therapeutics and Personal Care Products

Bioprospecting is the discovery and exploration of biological diversity found within organisms, genetic elements or produced compounds with prospective commercial or therapeutic applications. The human skin is an ecological niche which harbours a rich and compositional diversity microbiome stemming from the multifactorial interactions between the host and microbiota facilitated by exploitable effector compounds. Advances in the understanding of microbial colonisation mechanisms alongside species and strain interactions have revealed a novel chemical and biological understanding which displays applicative potential. Studies elucidating the organismal interfaces and concomitant understanding of the central processes of skin biology have begun to unravel a potential wealth of molecules which can exploited for their proposed functions. A variety of skin-microbiome-derived compounds display prospective therapeutic applications, ranging from antioncogenic agents relevant in skin cancer therapy to treatment strategies for antimicrobial-resistant bacterial and fungal infections. Considerable opportunities have emerged for the translation to personal care products, such as topical agents to mitigate various skin conditions such as acne and eczema. Adjacent compound developments have focused on cosmetic applications such as reducing skin ageing and its associated changes to skin properties and the microbiome. The skin microbiome contains a wealth of prospective compounds with therapeutic and commercial applications; however, considerable work is required for the translation of in vitro findings to relevant in vivo models to ensure translatability.

Probiotic-Derived Bioactive Compounds in Colorectal Cancer Treatment

Colorectal cancer (CRC) is a multifactorial disease with increased morbidity and mortality rates globally. Despite advanced chemotherapeutic approaches for the treatment of CRC, low survival rates due to the regular occurrence of drug resistance and deleterious side effects render the need for alternative anticancer agents imperative. Accumulating evidence supports that gut microbiota imbalance precedes the establishment of carcinogenesis, subsequently contributing to cancer progression and response to anticancer therapy. Manipulation of the gut microbiota composition via the administration of probiotic-derived bioactive compounds has gradually attained the interest of scientific communities as a novel therapeutic strategy for CRC. These compounds encompass miscellaneous metabolic secreted products of probiotics, including bacteriocins, short-chain fatty acids (SCFAs), lactate, exopolysaccharides (EPSs), biosurfactants, and bacterial peptides, with profound anti-inflammatory and antiproliferative properties. This review provides a classification of postbiotic types and a comprehensive summary of the current state of research on their biological role against CRC. It also describes how their intricate interaction with the gut microbiota regulates the proper function of the intestinal barrier, thus eliminating gut dysbiosis and CRC development. Finally, it discusses the future perspectives in precision-medicine approaches as well as the challenges of their synthesis and optimization of administration in clinical studies.

The Circular Bacteriocin enterocin NKR-5-3B has an Improved Stability Profile over Nisin

Bacteriocins are a large family of bacterial peptides that have antimicrobial activity and potential applications as clinical antibiotics or food preservatives. Circular bacteriocins are a unique class of these biomolecules distinguished by a seamless circular topology, and are widely assumed to be ultra-stable based on this constraining structural feature. However, without quantitative studies of their susceptibility to defined thermal, chemical, and enzymatic conditions, their stability characteristics remain poorly understood, limiting their translational development. Here, we produced the circular bacteriocin enterocin NKR-5-3B (Ent53B) in mg/L quantities using a heterologous Lactococcus expression system, and characterized its thermal stability by NMR, chemical stability by circular dichroism and analytical HPLC, and enzymatic stability by analytical HPLC. We demonstrate that Ent53B is ultra-stable, resistant to temperatures approaching boiling, acidic (pH 2.6) and alkaline (pH 9.0) conditions, the chaotropic agent 6M urea, and following incubation with a range of proteases (i.e., trypsin, chymotrypsin, pepsin, and papain), conditions under which most peptides and proteins degrade. Ent53B is stable across a broader range of pH conditions and proteases than nisin, the most widely used bacteriocin in food manufacturing. Antimicrobial assays showed that differences in stability correlated with differences in bactericidal activity. Overall, this study provides quantitative support for circular bacteriocins being an ultra-stable class of peptide molecules, suggesting easier handling and distribution options available to them in practical applications as antimicrobial agents.

TME-targeted approaches of brain metastases and its clinical therapeutic evidence

The tumor microenvironment (TME), which includes both cellular and non-cellular elements, is now recognized as one of the major regulators of the development of primary tumors, the metastasis of which occurs to specific organs, and the response to therapy. Development of immunotherapy and targeted therapies have increased knowledge of cancer-related inflammation Since the blood-brain barrier (BBB) and blood-cerebrospinal fluid barrier (BCB) limit immune cells from entering from the periphery, it has long been considered an immunological refuge. Thus, tumor cells that make their way "to the brain were believed to be protected from the body's normal mechanisms of monitoring and eliminating them. In this process, the microenvironment and tumor cells at different stages interact and depend on each other to form the basis of the evolution of tumor brain metastases. This paper focuses on the pathogenesis, microenvironmental changes, and new treatment methods of different types of brain metastases. Through the systematic review and summary from macro to micro, the occurrence and development rules and key driving factors of the disease are revealed, and the clinical precision medicine of brain metastases is comprehensively promoted. Recent research has shed light on the potential of TME-targeted and potential treatments for treating Brain metastases, and we'll use that knowledge to discuss the advantages and disadvantages of these approaches.

Design of Lactococcus lactis Strains Producing Garvicin A and/or Garvicin Q, Either Alone or Together with Nisin A or Nisin Z and High Antimicrobial Activity against Lactococcus garvieae

Lactococcus garvieae is a main ichthyopathogen in rainbow trout (Oncorhynchus mykiss, Walbaum) farming, although bacteriocinogenic L. garvieae with antimicrobial activity against virulent strains of this species have also been identified. Some of the bacteriocins characterized, such as garvicin A (GarA) and garvicin Q (GarQ), may show potential for the control of the virulent L. garvieae in food, feed and other biotechnological applications. In this study, we report on the design of Lactococcus lactis strains that produce the bacteriocins GarA and/or GarQ, either alone or together with nisin A (NisA) or nisin Z (NisZ). Synthetic genes encoding the signal peptide of the lactococcal protein Usp45 (SP_usp45), fused to mature GarA (lgnA) and/or mature GarQ (garQ) and their associated immunity genes (lgnI and garI, respectively), were cloned into the protein expression vectors pMG36c, which contains the P₃₂ constitutive promoter, and pNZ8048c, which contains the inducible P_nisA promoter. The transformation of recombinant vectors into lactococcal cells allowed for the production of GarA and/or GarQ by L. lactis subsp. cremoris NZ9000 and their co-production with NisA by Lactococcus lactis subsp. lactis DPC5598 and L. lactis subsp. lactis BB24. The strains L. lactis subsp. cremoris WA2-67 (pJFQI), a producer of GarQ and NisZ, and L. lactis subsp. cremoris WA2-67 (pJFQIAI), a producer of GarA, GarQ and NisZ, demonstrated the highest antimicrobial activity (5.1- to 10.7-fold and 17.3- to 68.2-fold, respectively) against virulent L. garvieae strains.