Direct attachment of nanoparticle cargo to Salmonella typhimurium membranes designed for combination bacteriotherapy against tumors

Nanotechnology impacting probiotics and prebiotics: a paradigm shift in nutraceuticals technology

This is proven for a long that the incorporation of probiotics and prebiotics in diet exhibits beneficial effects on intestinal and intrinsic health. Nevertheless, this may encounter loss of vitality all along the absorption in the gastrointestinal tract, leading to meager intestinal delivery of probiotic active ingredients. In recent times, nanotechnology has been passionately used to escalate the bioavailability of active ingredients. Versatile forms of nanoparticles (NPs) are devised to be used with probiotics/prebiotics/synbiotics or their different combinations. The NPs currently in trend are constituted of distinctive organic compounds like carbohydrates, proteins, fats, or inorganics such as oxides of silver and titanium or magnesium etc. This review critically explicates the emerging relationship of nanotechnology with probiotics and prebiotics for different applications in neutraceuticals. Here in this review, formulations of nanoprobiotics and nanoprebiotics are discussed in detail, which behave as an effective drug delivery system. In addition, these formulations exhibit anti-cancerous, anti-microbial, anti-oxidant and photo-protective properties. Limited availability of scientific research on nanotechnology concerning probiotics and prebiotics implies dynamic research studies on the bioavailability of loaded active ingredients and the effective drug delivery system by including the safety issues of food and the environment.

Recent Developments in the Study of the Microenvironment of Cancer and Drug Delivery

Cancer is characterized by disrupted molecular variables caused by cells that deviate from regular signal transduction. The uncontrolled segment of such cancerous cells annihilates most of the tissues that contact them. Gene therapy, immunotherapy, and nanotechnology advancements have resulted in novel strategies for anticancer drug delivery. Furthermore, diverse dispersion of nanoparticles in normal stroma cells adversely affects the healthy cells and disrupts the crosstalk of tumour stroma. It can contribute to cancer cell progression inhibition and, conversely, to acquired resistance, enabling cancer cell metastasis and proliferation. The tumour's microenvironment is critical in controlling the dispersion and physiological activities of nano-chemotherapeutics which is one of the targeted drug therapy. As it is one of the methods of treating cancer that involves the use of medications or other substances to specifically target and kill off certain subsets of malignant cells. A targeted therapy may be administered alone or in addition to more conventional methods of care like surgery, chemotherapy, or radiation treatment. The tumour microenvironment, stromatogenesis, barriers and advancement in the drug delivery system across tumour tissue are summarised in this review.

Photothermal Nanoheaters-Modified Spores for Safe and Controllable Antitumor Therapy

Introduction

To present a safer tumor therapy based on bacteria and identify in detail how the activation and infection behavior of spores can be controlled remotely by near-infrared light (NIR-irradiation) based on nanoheaters' modification.

Methods

Spores bring a better tolerance to surface modification. Transitive gold-nanorods-allied-nanoclusters-modified spores (Spore@NRs/NCs) were constructed by covalent glutaraldehyde crosslink. The photothermal properties of nanoheaters before and after attachment to spores were studied by recording temperature-irradiation time curves. The controlled viability and infection behavior of Spore@NRs/NCs were investigated by NIR-irradiation.

Results

In this work, a controllable sterilizing effect to activated vegetative bacteria was obtained obviously. When met with a suitable growth-environment, Spore@NRs/NCs could germinate, activate into vegetative bacteria and continue to reproduce. Without NIR-irradiation, nanoheaters could not affect the activity of both spores and vegetative bacterial cells. However, with NIR-irradiation after incubating in growth medium, nanoheaters on spores could control the spores' germination and affect the growth curve as well as the viability of the vegetative bacterial cells. For Spore@NRs/NCs (Spore:NCs:NRs=1:1:4, 67.5 μg mL^-1), a ~98% killing rate of vegetative bacterial cells was obtained with NIR-irradiation (2.8 W cm^-2, 20 min) after 2 h-incubation. In addition, these nanoheaters modified on spores could be taken not only to the vegetative bacteria cells, but also to the first-generation bacteria cells with their excellent photothermal and bactericidal performance, as well as synergetic anticancer effect. NIR-irradiation after 2 h-incubation could also trigger Spore@NRs/NCs (1:1:4, 6 μL) to synergistically reduce the viability of HCT116 cells to 15.63±2.90%.

Conclusion

By using NIR-irradiation, the "transitive" nanoheaters can remotely control the activity of both bacteria (germinated from spore) and cancer cells. This discovery provides basis and a feasible plan for controllable safer treatment of bacteria therapy, especially anaerobes with spores in hypoxic areas of the malignant solid tumors.

Advances in Salmonella Typhimurium-based drug delivery system for cancer therapy

The clinical application of bacteria-mediated immune therapy dates back over a century ago. In recent years, these strategies have advanced greatly with the rapid development of synthetic biology and nanotechnology. Several bacterial therapies have been developed allowing for more effective treatments for cancers, and Salmonella is one of the most studied bacterial species. Here, we review the advances in the bioengineered and functionalized Salmonella Typhimurium strains as drug delivery carries, including the various genetic circuits for programing these bacteria, the surface modification strategies using nanoparticles or other therapeutic agents for richer and broader features, and the bacterial component-based vehicles for cancer immunotherapy. This review will include the promises and challenges of these optimized Salmonella-based delivery systems and their related clinical trials. Ultimately, we hope to provide a spark of thought in the field of drug delivery and find important crosstalk between bacteria-mediated therapy and other different forms of treatments.

Innovative Approaches of Engineering Tumor-Targeting Bacteria with Different Therapeutic Payloads to Fight Cancer: A Smart Strategy of Disease Management

Conventional therapies for cancer eradication like surgery, radiotherapy, and chemotherapy, even though most widely used, still suffer from some disappointing outcomes. The limitations of these therapies during cancer recurrence and metastasis demonstrate the need for better alternatives. Some bacteria preferentially colonize and proliferate inside tumor mass; thus these bacteria can be used as ideal candidates to deliver antitumor therapeutic agents. The bacteria like Bacillus spp., Clostridium spp., E. coli, Listeria spp., and Salmonella spp. can be reprogrammed to produce, transport, and deliver anticancer agents, eg, cytotoxic agents, prodrug converting enzymes, immunomodulators, tumor stroma targeting agents, siRNA, and drug-loaded nanoformulations based on clinical requirements. In addition, these bacteria can be genetically modified to express various functional proteins and targeting ligands that can enhance the targeting approach and controlled drug-delivery. Low tumor-targeting and weak penetration power deep inside the tumor mass limits the use of anticancer drug-nanoformulations. By using anticancer drug nanoformulations and other therapeutic payloads in combination with antitumor bacteria, it makes a synergistic effect against cancer by overcoming the individual limitations. The tumor-targeting bacteria can be either used as a monotherapy or in addition with other anticancer therapies like photothermal therapy, photodynamic therapy, and magnetic field therapy to accomplish better clinical outcomes. The toxicity issues on normal tissues is the main concern regarding the use of engineered antitumor bacteria, which requires deeper research. In this article, the mechanism by which bacteria sense tumor microenvironment, role of some anticancer agents, and the recent advancement of engineering bacteria with different therapeutic payloads to combat cancers has been reviewed. In addition, future prospective and some clinical trials are also discussed.

Recognizing the Benefits of Pre-/Probiotics in Metabolic Syndrome and Type 2 Diabetes Mellitus Considering the Influence of Akkermansia muciniphila as a Key Gut Bacterium

Metabolic syndrome (MetS) and type 2 diabetes mellitus (T2DM) are diseases that can be influenced by the structure of gut microbiota, whose improvement is often neglected in metabolic pathology. This review highlights the following main aspects: the relationship between probiotics/gut microbes with the pathogenesis of MetS, the particular positive roles of Akkermansia muciniphila supplementation in the onset of MetS, and the interaction between dietary polyphenols (prebiotics) with gut microbiota. Therefore, an extensive and in-depth analysis of the often-neglected correlation between gut microbiota and chronic metabolic diseases was conducted, considering that this topic continues to fascinate and stimulate researchers through the discovery of novel strains and their beneficial properties.

An Updated Overview on Nanonutraceuticals: Focus on Nanoprebiotics and Nanoprobiotics

Over the last few years, the application of nanotechnology to nutraceuticals has been rapidly growing due to its ability to enhance the bioavailability of the loaded active ingredients, resulting in improved therapeutic/nutraceutical outcomes. The focus of this work is nanoprebiotics and nanoprobiotics, terms which stand for the loading of a set of compounds (e.g., prebiotics, probiotics, and synbiotics) in nanoparticles that work as absorption enhancers in the gastrointestinal tract. In this manuscript, the main features of prebiotics and probiotics are highlighted, together with the discussion of emerging applications of nanotechnologies in their formulation. Current research strategies are also discussed, in particular the promising use of nanofibers for the delivery of probiotics. Synbiotic-based nanoparticles represent an innovative trend within this area of interest. As only few experimental studies on nanoprebiotics and nanoprobiotics are available in the scientific literature, research on this prominent field is needed, covering effectiveness, bioavailability, and safety aspects.

Deliverable transgenics & gene therapy possibilities for the testes

Male infertility and hypogonadism are clinically prevalent conditions with a high socioeconomic burden and are both linked to an increased risk in cardiovascular-metabolic diseases and earlier mortality. Therefore, there is an urgent need to better understand the causes and develop new treatments for these conditions that affect millions of men. The accelerating advancement in gene editing and delivery technologies promises improvements in both diagnosis as well as affording the opportunity to develop bespoke treatment options which would both prove beneficial for the millions of individuals afflicted with these reproductive disorders. In this review, we summarise the systems developed and utilised for the delivery of gene therapy and discuss how each of these systems could be applied for the development of a gene therapy system in the testis and how they could be of use for the future diagnosis and repair of common male reproductive disorders.

A Geneticist's View of Prostate Cancer: Prostate Cancer Treatment Considerations

Prostate cancer remains a life-threatening disease of men. While early detection has been helpful to reduce the mortality rate, we currently do not have a desired therapy. In recent years, new strategies have been proposed to treat prostate cancers with poor prognosis by utilizing genetically modified bacteria, including Salmonella typhimurium that preferentially replicate within solid tumors (1000:1 and up to 10,000:1 compared to non-cancerous tissue) destroying cancer cells without causing septic shock that is typically associated with wild-type S. typhimurium infections. Furthermore, these bacteria have the potential to be utilized as drug delivery systems to more effectively target different subpopulations of prostate tumor cells. This chapter reviews progress in using genetically modified S. typhimurium for destruction of prostate tumors.

Salmonella Bacterial Monotherapy Reduces Autochthonous Prostate Tumor Burden in the TRAMP Mouse Model

Attenuated Salmonella typhimurium injected in the circulatory system of mammals selectively targets tumors. Using weekly intraperitoneal injections of attenuated Salmonella strain CRC2631, we tested for regression and/or inhibition of tumor development in the TRAMP prostate tumor mouse model, which utilizes SV40 early region expression for autochthonous formation of prostate tumors that progress into metastatic, poorly differentiated prostatic carcinomas in an immunocompetent murine model. Thirteen weekly intraperitoneal administrations of 10⁵–10⁷ CFU CRC2631 into 10 week old mice were well tolerated by the TRAMP model. Sacrifice and histological analysis of TRAMP prostates at 22 weeks indicated that Salmonella monotherapy at administrated levels decrease visible tumor size (>29%) but did not significantly inhibit previously described SV40 expression-driven TRAMP tumor progression to undifferentiated carcinomas when histologically examined. In conclusion, this work demonstrates baseline results for CRC2631 Salmonella monotherapy using the immunocompetent TRAMP prostate tumor model in preparation for study of combination therapies that resolve autochthonously generated TRAMP prostate tumors, further reduce tumor size, or inhibit prostate tumor progression.