Emerging applications of bacteria as antitumor agents

Quorum Sensing: Not Just a Bridge Between Bacteria

The study of quorum sensing (QS) has gained critical importance, offering insights into bacterial and microorganism communication. QS, regulated by autoinducers, synchronizes collective bacterial behaviors across diverse chemical signals and target genes. This review highlights innovative approaches to regulating QS, emphasizing the potential of quorum quenching and QS inhibitors to mitigate bacterial pathogenicity. These strategies have shown promise in aquaculture and plant resistance, disrupting QS pathways to combat infections. QS also provides opportunities for developing biosensors for early disease detection and preventing biofilm formation, which is critical to overcoming antimicrobial resistance. The applications of QS extend to cancer therapy, with targeted drug delivery systems utilizing QS mechanisms. Advancements in QS regulation, such as the use of nanomaterials, hydrogels, and microplastics, provide novel methods to modulate QS systems. This review explores the latest developments in QS, recognizing its significance in controlling bacterial behavior and its broad impacts on human health and disease management. Integrating these insights into therapeutic strategies and diagnostics represents a pivotal opportunity for medical progress.

Research progress on intratumoral microorganisms in renal cancer

The human body harbors a vast array of microorganisms. Changes in the microbial ecosystem can potentially lead to diseases, including cancer. Traditionally, research has focused more on the gut microbiota and its influence on cancer. However, with the advancement of sequencing technologies, scholars have discovered that microorganisms within kidney tissues are significant components of tumor tissues. Intratumoral microorganisms may affect tumor growth and development through certain mechanisms, influence the function of immune cells, or impact the effectiveness of chemotherapy or immunotherapy in patients. This paper reviews the latest progress in the research on intratumoral microorganisms in renal cancer (RCa). It summarizes the types and distribution characteristics of these microorganisms, discusses the close association between specific viral infections (such as HPV and EBV) and RCa, and highlights the role of microorganisms in the pathogenesis of RCa. This review provides new perspectives for understanding the pathogenic mechanisms of RCa, thereby offering potential clinical applications.

Bacterial Proteins and Peptides as Potential Anticancer Agents: A Novel Search for Protein-based Therapeutics

Tumor diseases remain among the world's primary causes of death despite substantial advances in cancer diagnosis and treatment. The adverse chemotherapy problems and sensitivity towards drugs for some cancer types are among the most promising challenges in modern treatment. Finding new anti-cancer agents and drugs is, therefore, essential. A significant class of biologically active substances and prospective medications against cancer is comprised of bacterial proteins and peptides. Among these bacterial peptides, some of them, such as anti-cancer antibiotics and many toxins like diphtheria are widely being used in the treatment of cancer. In contrast, the remaining bacterial peptides are either in clinical trials or under research in vitro studies. This study includes the most recent information on the characteristics and mechanism of action of the bacterial peptides that have anti-cancer activities, some of which are now being employed in cancer therapy while some are still undergoing research.

Innovative Bacterial Therapies and Genetic Engineering Approaches in Colorectal Cancer: A Review of Emerging Strategies and Clinical Implications

Colorectal cancer (CRC) is considered a widespread cancer, ranking second in mortality and incidence among cancer patients worldwide. CRC develops from adenoma to carcinoma through the dynamic interplay of genetic and environmental factors. The conventional modes of treatment, including operation, chemotherapy, and irradiation, are associated with significant challenges, such as drug resistance and toxicity, necessitating the exploration of new treatment modalities. These difficulties reveal the necessity of the emergence of new therapeutic approaches. This review mainly emphasizes the bacterial-based therapies that have recently developed like the engineered bacteriophage therapy and bacterial immunotherapy that pale the existing chemotherapy in terms of toxicity but are effective in killing tumor cells. Also, it also investigates various molecular genetic engineering strategies such as CRISPR-Cas9, CRISPR prime editing and gene silencing to achieve better targeting of CRC. Implementing these new approaches into the forefront of CRC treatment may bring better, more effective therapy with fewer side effects on patients' quality of life.

Converging frontiers in cancer treatment: the role of nanomaterials, mesenchymal stem cells, and microbial agents-challenges and limitations

Globally, people widely recognize cancer as one of the most lethal diseases due to its high mortality rates and lack of effective treatment options. Ongoing research into cancer therapies remains a critical area of inquiry, holding significant social relevance. Currently used treatment, such as chemotherapy, radiation, or surgery, often suffers from other problems like damaging side effects, inaccuracy, and the lack of ability to clear tumors. Conventional cancer therapies are usually imprecise and ineffective and usually develop resistance to treatments and cancer recurs. Cancer patients need fresh and innovative treatment that can reduce side effects while maximizing effectiveness. In recent decades several breakthroughs in these, and other areas of medical research, have paved the way for new avenues of fighting cancer including more focused and more effective alternatives. This study reviews exciting possibilities for mesenchymal stem cells (MSCs), nanomaterials, and microbial agents in the modern realm of cancer treatment. Nanoparticles (NPs) have demonstrated surprisingly high potential. They improve drug delivery systems (DDS) significantly, enhance imaging techniques remarkably, and target cancer cells selectively while protecting healthy tissues. MSCs play a double role in tissue repair and are a vehicle for novel cancer treatments such as gene treatments or NPs loaded with therapeutic agents. Additionally, therapies utilizing microbial agents, particularly those involving bacteria, offer an inventive approach to cancer treatment. This review investigates the potential of nanomaterials, MSCs, and microbial agents in addressing the shortcomings of conventional cancer therapies. We will also discuss the challenges and limitations of using these therapeutic approaches.

Design and computational analysis of a novel Azurin-BR2 chimeric protein against breast cancer

Cancer is one of most lethal diseases worldwide. Chemotherapeutics and surgeries are among the treatment facilities available for curing cancer. However due to their negative impact on normal cells and drug resistance development, new treatment strategies have yet to be developed. Some microbial products exhibit therapeutic potential for treating cancer. Pseudomonas aeruginosa Azurins have shown anticancer effects against breast cancer without affecting normal cells. To enhance its cytotoxic effect and targeted delivery, we fused Azurin with a cell-penetrating peptide (BR2) through a rigid linker and evaluated its anticancer potential via in silico analysis. The prediction of the secondary and the tertiary structures and analysis of physiochemical properties of chimeric proteins were computationally performed. The Azurin-BR2 chimeric protein has a basic nature with a molecular weight of 16.8 kDa. The quality indices and validation of chimeric proteins were performed with ERRAT2 and Ramachandran plot values, respectively. The quality index of the chimeric protein was predicted to be 81% to 84.6%, and residues residing in the most favoured region were identified. The HDOCK bioinformatics tool was used for docking a chimeric protein with a cancer suppressor protein p53. The results of the current study support that an Azurin-BR2 fusion protein has a high binding affinity for p53 can induce apoptosis in cancerous cells, and can be used in tumor-targeting therapy.

The Rational Engineered Bacteria Based Biohybrid Living System for Tumor Therapy

Living therapy based on bacterial cells has gained increasing attention for their applications in tumor treatments. Bacterial cells can naturally target to tumor sites and active the innate immunological responses. The intrinsic advantages of bacteria attribute to the development of biohybrid living carriers for targeting delivery toward hypoxic environments. The rationally engineered bacterial cells integrate various functions to enhance the tumor therapy and reduce toxic side effects. In this review, the antitumor effects of bacteria and their application are discussed as living therapeutic agents across multiple antitumor platforms. The various kinds of bacteria used for cancer therapy are first introduced and demonstrated the mechanism of antitumor effects as well as the immunological effects. Additionally, this study focused on the genetically modified bacteria for the production of antitumor agents as living delivery system to treat cancer. The combination of living bacterial cells with functional nanomaterials is then discussed in the cancer treatments. In brief, the rational design of living therapy based on bacterial cells highlighted a rapid development in tumor therapy and pointed out the potentials in clinical applications.

Scientists' call to action: Microbes, planetary health, and the Sustainable Development Goals

Microorganisms, including bacteria, archaea, viruses, fungi, and protists, are essential to life on Earth and the functioning of the biosphere. Here, we discuss the key roles of microorganisms in achieving the United Nations Sustainable Development Goals (SDGs), highlighting recent and emerging advances in microbial research and technology that can facilitate our transition toward a sustainable future. Given the central role of microorganisms in the biochemical processing of elements, synthesizing new materials, supporting human health, and facilitating life in managed and natural landscapes, microbial research and technologies are directly or indirectly relevant for achieving each of the SDGs. More importantly, the ubiquitous and global role of microbes means that they present new opportunities for synergistically accelerating progress toward multiple sustainability goals. By effectively managing microbial health, we can achieve solutions that address multiple sustainability targets ranging from climate and human health to food and energy production. Emerging international policy frameworks should reflect the vital importance of microorganisms in achieving a sustainable future.

Physiochemically and Genetically Engineered Bacteria: Instructive Design Principles and Diverse Applications

With the comprehensive understanding of microorganisms and the rapid advances of physiochemical engineering and bioengineering technologies, scientists are advancing rationally-engineered bacteria as emerging drugs for treating various diseases in clinical disease management. Engineered bacteria specifically refer to advanced physiochemical or genetic technologies in combination with cutting edge nanotechnology or physical technologies, which have been validated to play significant roles in lysing tumors, regulating immunity, influencing the metabolic pathways, etc. However, there has no specific reviews that concurrently cover physiochemically- and genetically-engineered bacteria and their derivatives yet, let alone their distinctive design principles and various functions and applications. Herein, the applications of physiochemically and genetically-engineered bacteria, and classify and discuss significant breakthroughs with an emphasis on their specific design principles and engineering methods objective to different specific uses and diseases beyond cancer is described. The combined strategies for developing in vivo biotherapeutic agents based on these physiochemically- and genetically-engineered bacteria or bacterial derivatives, and elucidated how they repress cancer and other diseases is also underlined. Additionally, the challenges faced by clinical translation and the future development directions are discussed. This review is expected to provide an overall impression on physiochemically- and genetically-engineered bacteria and enlighten more researchers.

Engineering Microorganisms for Cancer Immunotherapy

Cancer immunotherapy presents a promising approach to fight against cancer by utilizing the immune system. Recently, engineered microorganisms have emerged as a potential strategy in cancer immunotherapy. These microorganisms, including bacteria and viruses, can be designed and modified using synthetic biology and genetic engineering techniques to target cancer cells and modulate the immune system. This review delves into various microorganism-based therapies for cancer immunotherapy, encompassing strategies for enhancing efficacy while ensuring safety and ethical considerations. The development of these therapies holds immense potential in offering innovative personalized treatments for cancer.

Advances in bacteria-based drug delivery systems for anti-tumor therapy

In recent years, bacteria have gained considerable attention as a promising drug carrier that is critical in improving the effectiveness and reducing the side effects of anti-tumor drugs. Drug carriers can be utilised in various forms, including magnetotactic bacteria, bacterial biohybrids, minicells, bacterial ghosts and bacterial spores. Additionally, functionalised and engineered bacteria obtained through gene engineering and surface modification could provide enhanced capabilities for drug delivery. This review summarises the current studies on bacteria-based drug delivery systems for anti-tumor therapy and discusses the prospects and challenges of bacteria as drug carriers. Furthermore, our findings aim to provide new directions and guidance for the research on bacteria-based drug systems.

A biomimetic spore nanoplatform for boosting chemodynamic therapy and bacteria-mediated antitumor immunity for synergistic cancer treatment

Bacterial-based antitumor immunity has become a promising strategy to activate the immune system for fighting cancer. However, the potential application of bacterial therapy is hindered by the presence of instability and susceptibility to infections within bacterial populations. Furthermore, monotherapy is ineffective in completely eliminating complex cancer with multiple contributing factors. In this study, based on our discovery that spore shell (SS) of Bacillus coagulans exhibits excellent tumor-targeting ability and adjuvant activity, we develop a biomimetic spore nanoplatform to boost bacteria-mediated antitumor therapy, chemodynamic therapy and antitumor immunity for synergistic cancer treatment. In detail, SS is separated from probiotic spores and then attached to the surface of liposome (Lipo) that was loaded with hemoglobin (Hb), glucose oxidase (GOx) and JQ1 to construct SS@Lipo/Hb/GOx/JQ1. In tumor tissue, highly toxic hydroxyl radicals (•OH) are generated via sequential catalytic reactions: GOx catalyzing glucose into H2O2 and Fe2+ in Hb decomposing H2O2 into •OH. The combination of •OH and SS adjuvant can improve tumor immunogenicity and activate immune system. Meanwhile, JQ1-mediated down-regulation of PD-L1 and Hb-induced hypoxia alleviation synergistically reshape immunosuppressive tumor microenvironment and potentiate immune response. In this manner, SS@Lipo/Hb/GOx/JQ1 significantly suppresses tumor growth and metastasis. To summarize, the nanoplatform represents an optimum strategy to potentiate bacteria-based cancer immunotherapy.

Fn-OMV potentiates ZBP1-mediated PANoptosis triggered by oncolytic HSV-1 to fuel antitumor immunity

Oncolytic viruses (OVs) show promise as a cancer treatment by selectively replicating in tumor cells and promoting antitumor immunity. However, the current immunogenicity induced by OVs for tumor treatment is relatively weak, necessitating a thorough investigation of the mechanisms underlying its induction of antitumor immunity. Here, we show that HSV-1-based OVs (oHSVs) trigger ZBP1-mediated PANoptosis (a unique innate immune inflammatory cell death modality), resulting in augmented antitumor immune effects. Mechanistically, oHSV enhances the expression of interferon-stimulated genes, leading to the accumulation of endogenous Z-RNA and subsequent activation of ZBP1. To further enhance the antitumor potential of oHSV, we conduct a screening and identify Fusobacterium nucleatum outer membrane vesicle (Fn-OMV) that can increase the expression of PANoptosis execution proteins. The combination of Fn-OMV and oHSV demonstrates potent antitumor immunogenicity. Taken together, our study provides a deeper understanding of oHSV-induced antitumor immunity, and demonstrates a promising strategy that combines oHSV with Fn-OMV.

Genetically Engineered Microorganisms and Their Impact on Human Health

The emergence of antibiotic-resistant strains, the decreased effectiveness of conventional therapies, and the side effects have led researchers to seek a safer, more cost-effective, patient-friendly, and effective method that does not develop antibiotic resistance. With progress in synthetic biology and genetic engineering, genetically engineered microorganisms effective in treatment, prophylaxis, drug delivery, and diagnosis have been developed. The present study reviews the types of genetically engineered bacteria and phages, their impacts on diseases, cancer, and metabolic and inflammatory disorders, the biosynthesis of these modified strains, the route of administration, and their effects on the environment. We conclude that genetically engineered microorganisms can be considered promising candidates for adjunctive treatment of diseases and cancers.

Emerging Field of Nanotechnology in Environment

The art of utilizing and manipulating micro materials have been dated back to antient era. With the advancement in technologies, the state-of-art methods of nano technologies and nano sciences has been employed in various sectors including environment, product designing, food industry, pharmaceuticals industries to way out solve standard problem of mankind. Due to rapid industrialization and the alarming levels of pollution there has been an urgent need to address the environmental and energy issues. Environmental sustainability concerns the global climate change and pollution including air, water, soil. The field of nanotechnology has proven to be a promising field where sensing and remediation, have been dramatically advanced by the use of nanomaterials. This emergent science of surface to mass ratio is the principle theorem for manipulating structure at molecular levels. The review sums up all the advancements in the field of nanotechnology and their recent application in the environment. New opportunities and challenges have also been discussed in detail to understand the use of nanotechnology as problem-to-solution ratio.

Graphical abstract

Image depicting the application of nanotechnology in environmental concerns. The combinations of technologies like bioremediations, bioaugmentations with state-of-the-art nanotechnology like carbon nanotubes and Nano capsules to answer the environmental challenges of soil quality, and plant productivity.

Role of the gut microbiota in hematologic cancer

Hematologic neoplasms represent 6.5% of all cancers worldwide. They are characterized by the uncontrolled growth of hematopoietic and lymphoid cells and a decreased immune system efficacy. Pathological conditions in hematologic cancer could disrupt the balance of the gut microbiota, potentially promoting the proliferation of opportunistic pathogens. In this review, we highlight studies that analyzed and described the role of gut microbiota in different types of hematologic diseases. For instance, myeloma is often associated with Pseudomonas aeruginosa and Clostridium leptum, while in leukemias, Streptococcus is the most common genus, and Lachnospiraceae and Ruminococcaceae are less prevalent. Lymphoma exhibits a moderate reduction in microbiota diversity. Moreover, certain factors such as delivery mode, diet, and other environmental factors can alter the diversity of the microbiota, leading to dysbiosis. This dysbiosis may inhibit the immune response and increase susceptibility to cancer. A comprehensive analysis of microbiota-cancer interactions may be useful for disease management and provide valuable information on host-microbiota dynamics, as well as the possible use of microbiota as a distinguishable marker for cancer progression.

Total Bio-Based Material for Drug Delivery and Iron Chelation to Fight Cancer through Antimicrobial Activity

Bacterial involvement in cancer's development, along with their impact on therapeutic interventions, has been increasingly recognized. This has prompted the development of novel strategies to disrupt essential biological processes in microbial cells. Among these approaches, metal-chelating agents have gained attention for their ability to hinder microbial metal metabolism and impede critical reactions. Nanotechnology has also contributed to the antibacterial field by offering various nanomaterials, including antimicrobial nanoparticles with potential therapeutic and drug-delivery applications. Halloysite nanotubes (HNTs) are naturally occurring tubular clay nanomaterials composed of aluminosilicate kaolin sheets rolled multiple times. The aluminum and siloxane groups on the surface of HNTs enable hydrogen bonding with biomaterials, making them versatile in various domains, such as environmental sciences, wastewater treatment, nanoelectronics, catalytic studies, and cosmetics. This study aimed to create an antibacterial material by combining the unique properties of halloysite nanotubes with the iron-chelating capability of kojic acid. A nucleophilic substitution reaction involving the hydroxyl groups on the nanotubes' surface was employed to functionalize the material using kojic acid. The resulting material was characterized using infrared spectroscopy (IR), thermogravimetric analysis (TGA), energy-dispersive X-ray spectroscopy (EDX), and scanning electron microscopy (SEM), and its iron-chelating ability was assessed. Furthermore, the potential for drug loading-specifically, with resveratrol and curcumin-was evaluated through ultraviolet (UV) analysis. The antibacterial assay was evaluated following CLSI guidelines. The results suggested that the HNTs-kojic acid formulation had great antibacterial activity against all tested pathogens. The outcome of this work yielded a novel bio-based material with dual functionality as a drug carrier and an antimicrobial agent. This innovative approach holds promise for addressing challenges related to bacterial infections, antibiotic resistance, and the development of advanced therapeutic interventions.

Therapeutic Approaches in Pancreatic Cancer: Recent Updates

Cancer is a significant challenge for effective treatment due to its complex mechanism, different progressing stages, and lack of adequate procedures for screening and identification. Pancreatic cancer is typically identified in its advanced progression phase with a low survival of ~5 years. Among cancers, pancreatic cancer is also considered a high mortality-causing casualty over other accidental or disease-based mortality, and it is ranked seventh among all mortality-associated cancers globally. Henceforth, developing diagnostic procedures for its early detection, understanding pancreatic cancer-linked mechanisms, and various therapeutic strategies are crucial. This review describes the recent development in pancreatic cancer progression, mechanisms, and therapeutic approaches, including molecular techniques and biomedicines for effectively treating cancer.

Genome-resolved metagenomics revealed metal-resistance, geochemical cycles in a Himalayan hot spring

The hot spring microbiome is a complex assemblage of micro- and macro-organisms; however, the understanding and projection of enzymatic repertoire that access earth's integral ecosystem processes remains ambivalent. Here, the Khirganga hot spring characterized with white microbial mat and ions rich in sulfate, chlorine, sodium, and magnesium ions is investigated and displayed the examination of 41 high and medium qualified metagenome-assembled genomes (MAGs) belonged to at least 12 bacterial and 2 archaeal phyla which aids to drive sulfur, oxygen, iron, and nitrogen cycles with metabolic mechanisms involved in heavy metal tolerance. These MAGs possess over 1749 genes putatively involved in crucial metabolism of elements viz. nitrogen, phosphorus, and sulfur and 598 genes encoding enzymes for czc efflux system, chromium, arsenic, and copper heavy metals resistance. The MAGs also constitute 229 biosynthetic gene clusters classified abundantly as bacteriocins and terpenes. The metabolic roles possibly involved in altering linkages in nitrogen biogeochemical cycles and explored a discerned rate of carbon fixation exclusively in archaeal member Methanospirillum hungatei inhabited in microbial mat. Higher Pfam entropy scores of biogeochemical cycling in Proteobacteria members assuring their major contribution in assimilation of ammonia and sequestration of nitrate and sulfate components as electron acceptors. This study will readily improve the understanding of the composite relationship between bacterial species owning metal resistance genes (MRGs) and underline the exploration of adaptive mechanism of these MAGs in multi-metal contaminated environment. KEY POINTS: • Identification of 41 novel bacterial and archaeal species in habitats of hot spring • Genome-resolved metagenomics revealed MRGs (n = 598) against Cr, Co, Zn, Cd, As, and Cu • Highest entropies of N (0.48) and Fe (0.44) cycles were detected within the MAGs.

Molecular Mechanisms and Applications of N-Acyl Homoserine Lactone-Mediated Quorum Sensing in Bacteria

Microbial biodiversity includes biotic and abiotic components that support all life forms by adapting to environmental conditions. Climate change, pollution, human activity, and natural calamities affect microbial biodiversity. Microbes have diverse growth conditions, physiology, and metabolism. Bacteria use signaling systems such as quorum sensing (QS) to regulate cellular interactions via small chemical signaling molecules which also help with adaptation under undesirable survival conditions. Proteobacteria use acyl-homoserine lactone (AHL) molecules as autoinducers to sense population density and modulate gene expression. The LuxI-type enzymes synthesize AHL molecules, while the LuxR-type proteins (AHL transcriptional regulators) bind to AHLs to regulate QS-dependent gene expression. Diverse AHLs have been identified, and the diversity extends to AHL synthases and AHL receptors. This review comprehensively explains the molecular diversity of AHL signaling components of Pseudomonas aeruginosa, Chromobacterium violaceum, Agrobacterium tumefaciens, and Escherichia coli. The regulatory mechanism of AHL signaling is also highlighted in this review, which adds to the current understanding of AHL signaling in Gram-negative bacteria. We summarize molecular diversity among well-studied QS systems and recent advances in the role of QS proteins in bacterial cellular signaling pathways. This review describes AHL-dependent QS details in bacteria that can be employed to understand their features, improve environmental adaptation, and develop broad biomolecule-based biotechnological applications.

Vibrational spectroscopy for decoding cancer microbiota interactions: Current evidence and future perspective

The role of human microbiota in cancer initiation and progression is recognized in recent years. In order to investigate the interactions between cancer cells and microbes, a systematic analysis using various emerging techniques is required. Owing to the label-free, non-invasive and molecular fingerprinting characteristics, vibrational spectroscopy is uniquely suited to decode and understand the relationship and interactions between cancer and the microbiota at the molecular level. In this review, we first provide a quick overview of the fundamentals of vibrational spectroscopic techniques, namely Raman and infrared spectroscopy. Next, we discuss the emerging evidence underscoring utilities of these spectroscopic techniques to study cancer or microbes separately, and share our perspective on how vibrational spectroscopy can be employed at the intersection of the two fields. Finally, we envision the potential opportunities in exploiting vibrational spectroscopy not only in basic cancer-microbiome research but also in its clinical translation, and discuss the challenges in the bench to bedside translation.

Gut Microbiota and Clostridium difficile: What We Know and the New Frontiers

Our digestive system, particularly our intestines, harbors a vast amount of microorganisms, whose genetic makeup is referred to as the microbiome. Clostridium difficile is a spore-forming Gram-positive bacterium, which can cause an infection whose symptoms range from asymptomatic colonization to fearsome complications such as the onset of toxic megacolon. The relationship between gut microbiota and Clostridium difficile infection has been studied from different perspectives. One of the proposed strategies is to be able to specifically identify which types of microbiota alterations are most at risk for the onset of CDI. In this article, we understood once again how crucial the role of the human microbiota is in health and especially how crucial it becomes, in the case of its alteration, for the individual's disease. Clostridium difficile infection is an emblematic example of how a normal and physiological composition of the human microbiome can play a very important role in immune defense against such a fearsome disease.

Genetically engineered bacterium: Principles, practices, and prospects

Advances in synthetic biology and the clinical application of bacteriotherapy enable the use of genetically engineered bacteria (GEB) to combat various diseases. GEB act as a small 'machine factory' in the intestine or other tissues to continuously produce heterologous proteins or molecular compounds and, thus, diagnose or cure disease or work as an adjuvant reagent for disease treatment by regulating the immune system. Although the achievements of GEBs in the treatment or adjuvant therapy of diseases are promising, the practical implementation of this new therapeutic modality remains a grand challenge, especially at the initial stage. In this review, we introduce the development of GEBs and their advantages in disease management, summarize the latest research advances in microbial genetic techniques, and discuss their administration routes, performance indicators and the limitations of GEBs used as platforms for disease management. We also present several examples of GEB applications in the treatment of cancers and metabolic diseases and further highlight their great potential for clinical application in the near future.

Evaluation of TiO2 Nanoparticles Physicochemical Parameters Associated with their Antimicrobial Applications

Titanium dioxide nanoparticles (TiO2NPs) usage is increasing in everyday consumer products, hence, assessing their toxic impacts on living organisms and environment is essential. Various studies have revealed the significant role of TiO2NPs physicochemical properties on their toxicity. However, TiO2NPs are still poorly characterized with respect to their physicochemical properties, and environmental factors influencing their toxicity are either ignored or are too complex to be assessed under laboratory conditions. The outcomes of these studies are diverse and inconsistent due to lack of standard protocols. TiO2NPs toxicity also differs for in vivo and in vitro systems, which must also be considered during standardization of protocols to maintain uniformity and reproducibility of results. This review critically evaluates impact of different physicochemical parameters of TiO2NPs and other experimental conditions, employed in different laboratories in determining their toxicity towards bacteria. These important observations may be helpful in evaluation of environmental risks posed by these nanoparticles and this can further assist regulatory bodies in policymaking.

Therapeutic Applications of Self-assembled Indole-3-butanoyl-polyethylenimine Nanostructures

This study demonstrates the therapeutic potential of indole-3-butanoyl-polyethylenimine (IBP) nanostructures formed via self-assembly in aqueous system. Dynamic light scattering (DLS) analysis confirmed the formation of the nanostructures in the size range of ~ 194-331 nm. These nanostructures showed commendable antimicrobial activity against wide range of microbes including multi-drug resistant bacteria. Besides, appreciable antioxidant and anti-inflammatory activities were also observed. Results of cytotoxicity studies, performed on normal transformed human embryonic kidney (HEK 293) cells and human red blood cells (hRBCs), revealed almost non-toxic behavior of these nanostructures, however, remarkable toxicity on human breast cancer cells (MCF-7), human osteosarcoma cells (Mg63) and human liver cancer cells (HepG2) was observed. The pre-apoptotic and anti-proliferative activity of IBP nanostructures were confirmed by acridine orange/propidium iodide dual staining assay followed by confocal microscopy and scratch assay on Mg63 cells. Taken together, these results advocate the promising potential of the synthesized IBP nanostructures in the therapeutic applications.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12088-022-01015-y.

Biogenic Synthesis of CuO, ZnO, and CuO-ZnO Nanoparticles Using Leaf Extracts of Dovyalis caffra and Their Biological Properties

Biogenic metal oxide nanoparticles (NPs) have emerged as a useful tool in biology due to their biocompatibility properties with most biological systems. In this study, we report the synthesis of copper oxide (CuO), zinc oxide (ZnO) nanoparticles (NPs), and their nanocomposite (CuO–ZnO) prepared using the phytochemical extracts from the leaves of Dovyalis caffra (kei apple). The physicochemical properties of these nanomaterials were established using some characterization techniques including X-ray diffraction analysis (XRD), ultraviolet-visible spectroscopy (UV-vis), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy-dispersive X-ray spectroscopy (EDX). The XRD result confirmed the presence of a monoclinic CuO (Tenorite), and a hexagonal ZnO (Zincite) nanoparticles phase, which were both confirmed in the CuO–ZnO composite. The electron microscopy of the CuO–ZnO, CuO, and ZnO NPs showed a mixture of nano-scale sizes and spherical/short-rod morphologies, with some agglomeration. In the constituent’s analysis (EDX), no unwanted peak was found, which showed the absence of impurities. Antioxidant properties of the nanoparticles was studied, which confirmed that CuO–ZnO nanocomposite exhibited better scavenging potential than the individual metal oxide nanoparticles (CuO, and ZnO), and ascorbic acid with respect to their minimum inhibitory concentration (IC₅₀) values. Similarly, the in vitro anticancer studies using MCF7 breast cancer cell lines indicated a concentration-dependent profile with the CuO–ZnO nanocomposite having the best activity over the respective metal oxides, but slightly lower than the standard 5-Fluorouracil drug.

Alterations of the Gut Microbiome in Recurrent Malignant Gliomas Patients Received Bevacizumab and Temozolomide Combination Treatment and Temozolomide Monotherapy

This case-control study explored compositions of gut microbiome in recurrent malignant gliomas patients who had received bevacizumab and Temozolomide combination treatment and Temozolomide monotherapy. We investigated gut microbiota communities in feces of 29 recurrent malignant gliomas patients received combination treatment with bevacizumab and Temozolomide (Group 1) and monotherapy with Temozolomide alone (Group 2). We took advantage of the high-throughput Illumina Miseq sequencing technology by targeting the third and fourth hypervariable (V3-V4) regions of the 16S ribosomal RNA (rRNA) gene. We found that the structures and richness of the fecal microbiota in Group 1 were different from Group 2 with LEfSe analysis. The fecal microbiota in both Group 1 and Group 2 were mainly composed by Firmicutes, Proteobacteria, Bacteroidetes and Actinobacteria. However, Group 1 patients had higher relative abundance of Firmicutes, Bacteroidetes, Actinobacteria and lower relative abundance of Bacteroidetes and Cyanobacteria in their fecal microbiota than that in Group 2 patients. To evaluate bevacizumab involved post-treatment state of the fecal microbiota profile, we used random forest predictive model and ensembled decision trees with an AUC of 0.54. This study confirmed that the gut microbiota was different in recurrent malignant gliomas patients received the combination therapy of bevacizumab and Temozolomide compared with Temozolomide monotherapy. Our discover can help better understand the influence of bevacizumab related treatment on recurrent malignant gliomas patients. Therefore, this finding may also support the potentially therapeutic options for recurrent malignant gliomas patients such as fecal microbiota transplant.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s12088-021-00962-2.

Cellular Apoptosis Induced by Deoxynivalenol

Deoxynivalenol (DON) is synthesized by Fusarium species that frequently infect crops during storage, and it's harm risk to human is reflected in the consumption of infected food crops or indirectly through foods of animal origin. In this study, Hela and Chang liver cells were used to research the cellular apoptosis induced by deoxynivalenol. Cells were treated by DON toxin with a series of concentration and incubated for different time. MTT, fluorescence microscope, flow cytometer and Western blot methods were used to analyze the effect of DON on the cell apoptosis in vitro and in vivo systematically. The results showed that DON was toxic to the cells tested. After being treated by DON, the morphology of Chang livers and Hela cells changed significantly. The DON promoted apoptosis in a dose- and time-dependent manner. The activity of Caspase 3 was significantly increased in DON-induced apoptosis. Moreover, endogenous Glutathione (GSH) level in these cell lines was gradually decreased. In the early apoptosis progress, oxidative stress was induced by DON. When DON reached 10 µg/mL, a markedly increased content of Malondialdehyde (MDA) was detected in both Hela and Chang liver cells. Furthermore, an in vivo test indicated that DON had toxicity to mice by causing weight loss and swollen spleen, and significantly increased expression of AST and ALT. In conclusion, the DON was toxic to mice and could induce the apoptosis of tested cells undergoing a Caspase-3 related pathway.

The Emerging Biotherapeutic Agent: Akkermansia

The human gastrointestinal tract (GIT) is a well-recognized hub of microbial activities. The microbiota harboring the mucus layer of the GIT act as a defense against noxious substances, and pathogens including Clostridium difficile, Enterococcus faecium, Escherichia coli, Salmonella Typhimurium. Toxins, pathogens, and antibiotics perturb the commensal floral composition within the GIT. Imbalanced gut microbiota leads to dysbiosis, manifested as diseases ranging from obesity, diabetes, and cancer to reduced lifespan. Among the bacteria present in the gut microbiome, the most beneficial are those representing Firmicutes and Bacteroidetes. Recent studies have revealed the emergence of a novel biotherapeutic agent, Akkermansia, which is instrumental in regaining eubiosis and conferring various health benefits.

Biomolecules Production from Greenhouse Gases by Methanotrophs

Harmful effects on living organisms and the environment are on the rise due to a significant increase in greenhouse gas (GHG) emissions through human activities. Therefore, various research initiatives have been carried out in several directions in relation to the utilization of GHGs via physicochemical or biological routes. An environmentally friendly approach to reduce the burden of significant emissions and their harmful effects is the bioconversion of GHGs, including methane (CH4) and carbon dioxide (CO2), into value-added products. Methanotrophs have enormous potential for the efficient biotransformation of CH4 to various bioactive molecules, including biofuels, polyhydroxyalkanoates, and fatty acids. This review highlights the recent developments in methanotroph-based systems for methanol production from GHGs and proposes future perspectives to improve process sustainability via biorefinery approaches.

Microbiota Alterations and Their Association with Oncogenomic Changes in Pancreatic Cancer Patients

Pancreatic cancer (PC) is an aggressive disease with a high mortality and poor prognosis. The human microbiome is a key factor in many malignancies, having the ability to alter host metabolism and immune responses and participate in tumorigenesis. Gut microbes have an influence on physiological functions of the healthy pancreas and are themselves controlled by pancreatic secretions. An altered oral microbiota may colonize the pancreas and cause local inflammation by the action of its metabolites, which may lead to carcinogenesis. The mechanisms behind dysbiosis and PC development are not completely clear. Herein, we review the complex interactions between PC tumorigenesis and the microbiota, and especially the question, whether and how an altered microbiota induces oncogenomic changes, or vice versa, whether cancer mutations have an impact on microbiota composition. In addition, the role of the microbiota in drug efficacy in PC chemo- and immunotherapies is discussed. Possible future scenarios are the intentional manipulation of the gut microbiota in combination with therapy or the utilization of microbial profiles for the noninvasive screening and monitoring of PC.

Anaerobic Digestion of Agri-Food Wastes for Generating Biofuels

Presently, fossil fuels are extensively employed as major sources of energy, and their uses are considered unsustainable due to emissions of obnoxious gases on the burning of fossil fuels, which can lead to severe environmental complications, including human health. To tackle these issues, various processes are developing to waste as a feed to generate eco-friendly fuels. The biological production of fuels is considered to be more beneficial than physicochemical methods due to their environmentally friendly nature, high rate of conversion at ambient physiological conditions, and less energy-intensive. Among various biofuels, hydrogen (H₂) is considered as a wonderful due to high calorific value and generate water molecule as end product on the burning. The H₂ production from biowaste is demonstrated, and agri-food waste can be potentially used as a feedstock due to their high biodegradability over lignocellulosic-based biomass. Still, the H₂ production is uneconomical from biowaste in fuel competing market because of low yields and increased capital and operational expenses. Anaerobic digestion is widely used for waste management and the generation of value-added products. This article is highlighting the valorization of agri-food waste to biofuels in single (H₂) and two-stage bioprocesses of H₂ and CH₄ production.

Photocatalytic TiO2/CdS/ZnS nanocomposite induces Bacillus subtilis cell death by disrupting its metabolism and membrane integrity

Titanium dioxide (TiO₂) is widely characterized for its application in clinical diagnostics, therapeutics, cosmetics, nutrition, and environment management. Despite enormous potential, its dependence on ultraviolet (UV) light for photocatalytic activity limits its commercialization. Accordingly in the present study, a photo catalytically superior ternary complex of TiO₂ with Cadmium sulfide/Zinc sulfide (CdS/ZnS) has been synthesized, as well as, characterized for photo-induced antimicrobial activity. The band gap of crystalline TiO₂/CdS/ZnS nanocomposite has been reduced (2.26 eV) and nanocomposite has shown the optimal photo-activation at 590 nm. TiO₂ nanocomposite has significant bactericidal activity in visible light (P < 0.01). Exposure of the TiO₂ nanocomposite affected the cellular metabolism by altering the 1681 metabolic features (P < 0.001) culminating in poor cellular survivability. Additionally, photo-induced reactive oxygen species generation through nanocomposite disrupts the microbial cellular structure. The present study synthesized photocatalytic nanocomposite as well as unveiled the holistic cellular effect of theTiO₂/CdS/ZnS nanocomposite. Additionally, the present study also indicated the potential application of TiO₂/CdS/ZnS nanocomposite for sustainable environment management, therapeutics, and various industries.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12088-021-00973-z.

The role of the tumor microbe microenvironment in the tumor immune microenvironment: bystander, activator, or inhibitor?

The efficacy of cancer immunotherapy largely depends on the tumor microenvironment, especially the tumor immune microenvironment. Emerging studies have claimed that microbes reside within tumor cells and immune cells, suggesting that these microbes can impact the state of the tumor immune microenvironment. For the first time, this review delineates the landscape of intra-tumoral microbes and their products, herein defined as the tumor microbe microenvironment. The role of the tumor microbe microenvironment in the tumor immune microenvironment is multifaceted: either as an immune activator, inhibitor, or bystander. The underlying mechanisms include: (I) the presentation of microbial antigens by cancer cells and immune cells, (II) microbial antigens mimicry shared with tumor antigens, (III) microbe-induced immunogenic cell death, (IV) microbial adjuvanticity mediated by pattern recognition receptors, (V) microbe-derived metabolites, and (VI) microbial stimulation of inhibitory checkpoints. The review further suggests the use of potential modulation strategies of the tumor microbe microenvironment to enhance the efficacy and reduce the adverse effects of checkpoint inhibitors. Lastly, the review highlights some critical questions awaiting to be answered in this field and provides possible solutions. Overall, the tumor microbe microenvironment modulates the tumor immune microenvironment, making it a potential target for improving immunotherapy. It is a novel field facing major challenges and deserves further exploration.

Bacteria-based immune therapies for cancer treatment

Engineered bacterial therapies that target the tumor immune landscape offer a new class of cancer immunotherapy. Salmonella enterica and Listeria monocytogenes are two species of bacteria that have been engineered to specifically target tumors and serve as delivery vessels for immunotherapies. Therapeutic bacteria have been engineered to deliver cytokines, gene silencing shRNA, and tumor associated antigens that increase immune activation. Bacterial therapies stimulate both the innate and adaptive immune system, change the immune dynamics of the tumor microenvironment, and offer unique strategies for targeting tumors. Bacteria have innate adjuvant properties, which enable both the delivered molecules and the bacteria themselves to stimulate immune responses. Bacterial immunotherapies that deliver cytokines and tumor-associated antigens have demonstrated clinical efficacy. Harnessing the diverse set of mechanisms that Salmonella and Listeria use to alter the tumor-immune landscape has the potential to generate many new and effective immunotherapies.

Biotin and Zn2+ Increase Xylitol Production by Candida tropicalis

In this study, the medium requirements to increase the production of xylitol by using Candida tropicalis (CT) have been investigated. The technique of single addition or omission of medium components was applied to determine the nutritional requirements. The addition of amino acids such as Asp, Glu, Gln, Asn, Thr, and Gly had no significant effect on CT growth. However, in the absence of other metal ions, there was a higher concentration of cell growth and xylitol production when only Zn2+ was present in the medium. The analysis of various vitamins unveiled that biotin and thiamine were the only vitamins required for the growth of CT. Surprisingly, when only biotin was present in the medium as a vitamin, there was less growth of CT than when the medium was complete, but the amount of xylitol released was significantly higher. Overall, this study will increase the xylitol production using the single omission or addtion technique.

Helicobacters and cancer, not only gastric cancer?

The Helicobacter genus actually comprises 46 validly published species divided into two main clades: gastric and enterohepatic Helicobacters. These bacteria colonize alternative sites of the digestive system in animals and humans, and contribute to inflammation and cancers. In humans, Helicobacter infection is mainly related to H. pylori, a gastric pathogen infecting more than half of the world's population, leading to chronic inflammation of the gastric mucosa that can evolve into two types of gastric cancers: gastric adenocarcinomas and gastric MALT lymphoma. In addition, H. pylori but also non-H. pylori Helicobacter infection has been associated with many extra-gastric malignancies. This review focuses on H. pylori and its role in gastric cancers and extra-gastric diseases, as well as malignancies induced by non-H. pylori Helicobacters. Their different virulence factors and their involvement in carcinogenesis is discussed. This review highlights the importance of both gastric and enterohepatic Helicobacters in gastrointestinal and liver cancers.

Boron and Gadolinium Loaded Fe3O4 Nanocarriers for Potential Application in Neutron Capture Therapy

In this article, a novel method of simultaneous carborane- and gadolinium-containing compounds as efficient agents for neutron capture therapy (NCT) delivery via magnetic nanocarriers is presented. The presence of both Gd and B increases the efficiency of NCT and using nanocarriers enhances selectivity. These factors make NCT not only efficient, but also safe. Superparamagnetic Fe3O4 nanoparticles were treated with silane and then the polyelectrolytic layer was formed for further immobilization of NCT agents. Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), energy dispersive X-ray (EDX), ultraviolet-visible (UV-Vis) and Mössbauer spectroscopies, dynamic light scattering (DLS), scanning electron microscopy (SEM), vibrating-sample magnetometry (VSM) were applied for the characterization of the chemical and element composition, structure, morphology and magnetic properties of nanocarriers. The cytotoxicity effect was evaluated on different cell lines: BxPC-3, PC-3 MCF-7, HepG2 and L929, human skin fibroblasts as normal cells. average size of nanoparticles is 110 nm; magnetization at 1T and coercivity is 43.1 emu/g and 8.1, respectively; the amount of B is 0.077 mg/g and the amount of Gd is 0.632 mg/g. Successful immobilization of NCT agents, their low cytotoxicity against normal cells and selective cytotoxicity against cancer cells as well as the superparamagnetic properties of nanocarriers were confirmed by analyses above.

Novel Hybrid Compounds Containing Benzofuroxan and Aminothiazole Scaffolds: Synthesis and Evaluation of Their Anticancer Activity

A series of novel hybrid compounds containing benzofuroxan and 2-aminothiazole moieties are synthesized via aromatic nucleophilic substitution reaction. Possible reaction pathways have been considered quantum-chemically, which allowed us to suggest the most probable products. The quantum chemical results have been proved by X-ray data on one compound belonging to the synthesized series. It was shown that the introduction of substituents to both the thiazole and amine moieties of the compounds under study strongly influences their UV/Vis spectra. Initial substances and obtained hybrid compounds have been tested in vitro as anticancer agents. Target compounds showed selectivity towards M-HeLa tumor cell lines and were found to be more active than starting benzofuroxan and aminothiazoles. Furthermore, they are considerably less toxic to normal liver cells compared to Tamoxifen. The mechanism of action of the studied compounds can be associated with the induction of apoptosis, which proceeds along the mitochondrial pathway. Thus, new hybrids of benzofuroxan are promising candidates for further development as anticancer agents.

In Search of Effective Anticancer Agents-Novel Sugar Esters Based on Polyhydroxyalkanoate Monomers

Cancer is one of the deadliest illness globally. Searching for new solutions in cancer treatments is essential because commonly used mixed, targeted and personalized therapies are sometimes not sufficient or are too expensive for common patients. Sugar fatty acid esters (SFAEs) are already well-known as promising candidates for an alternative medical tool. The manuscript brings the reader closer to methods of obtaining various SFAEs using combined biological, chemical and enzymatic methods. It presents how modification of SFAE's hydrophobic chains can influence their cytotoxicity against human skin melanoma and prostate cancer cell lines. The compound's cytotoxicity was determined by an MTT assay, which followed an assessment of SFAEs' potential metastatic properties in concentrations below IC50 values. Despite relatively high IC50 values (63.3-1737.6 μM) of the newly synthesized SFAE, they can compete with other sugar esters already described in the literature. The chosen bioactives caused low polymerization of microtubules and the depolymerization of actin filaments in nontoxic levels, which suggest an apoptotic rather than metastatic process. Altogether, cancer cells showed no propensity for metastasis after treating them with SFAE. They confirmed that lactose-based compounds seem the most promising surfactants among tested sugar esters. This manuscript creates a benchmark for creation of novel anticancer agents based on 3-hydroxylated fatty acids of bacterial origin.