Application Value of Antimicrobial Peptides in Gastrointestinal Tumors

The Potential Effect of Endogenous Antimicrobial Peptides in Cancer Immunotherapy and Prevention

Antimicrobial peptides (AMPs) are crucial constituents of inherent immunity and serve as vital components of human host defense, playing a pivotal role in combating invading microbial pathogens. Beyond their antimicrobial functions, AMPs also exhibit various other biological activities including apoptosis induction, wound healing promotion, and immune modulation. These peptides are found in various exposed tissues or surfaces throughout the body, such as eyes, skin, mouth, ears, respiratory tract, lungs, digestive, and urinary system. Additionally, certain AMPs such as LL-37, HNP, and lactoferrin have shown potential as candidates for anticancer activity. Given the limited selectivity between normal and cancer cells exhibited by many current immunotherapeutic agents, the inherent properties of AMPs make them promising candidates for cancer treatment. Their abundance, bioavailability, safety profile, efficiency, and harmony with the host immune system position them as attractive tools in the fight against cancer. This review is aimed at exploring the potential anticancer properties of AMPs and elucidating their relationship with immunology and cancer immunotherapy.

A Zeolitic Imidazolate Framework-Based Antimicrobial Peptide Delivery System with Enhanced Anticancer Activity and Low Systemic Toxicity

BACKGROUND

The clinical efficacies of anticancer drugs are limited by non-selective toxic effects on healthy tissues and low bioavailability in tumor tissue. Therefore, the development of vehicles that can selectively deliver and release drugs at the tumor site is critical for further improvements in patient survival.

METHODS

We prepared a CEC nano-drug delivery system, CEC@ZIF-8, with a zeolite imidazole framework-8 (ZIF-8) as a carrier, which can achieve the response of folate receptor (FR). We characterized this system in terms of morphology, particle size, zeta potential, infrared (IR), x-ray diffraction (XRD), and transcriptome analysis, and examined the in vitro cytotoxicity and cellular uptake properties of CEC@ZIF-8 using cervical cancer cells. Lastly, we established a TC-1 tumor-bearing mouse model and evaluated its in vivo anti-cervical cancer activity.

RESULTS

The CEC@ZIF-8 nano-delivery system had favorable biocompatibility, heat stability, and pH responsiveness, with a CEC loading efficiency of 12%, a hydrated particle size of 174 ± 5.8 nm, a zeta potential of 20.57 mV, and slow and massive drug release in an acidic environment (pH 5.5), whereas release was 6% in a neutral environment (pH 7.4). At the same time, confocal imaging and cell viability assays demonstrated greater intracellular accumulation and more potent cytotoxicity against cancer cells compared to free CEC. The mechanism was analyzed by a series of transcriptome analyses, which revealed that CEC@ZIF-8 NPs differentially regulate the expression levels of 1057 genes in cancer cells, and indicated that the enriched pathways were mainly cell cycle and apoptosis-related pathways via the enrichment analysis of the differential genes. Flow cytometry showed that CEC@ZIF-8 NPs inhibited the growth of HeLa cells by arresting the cell cycle at the G0/G1 phase. Flow cytometry also revealed that CEC@ZIF-8 NPs induced greater apoptosis rates than CEC, while unloaded ZIF-8 had little inherent pro-apoptotic activity. Furthermore, the levels of reactive oxygen species (ROS) were also upregulated by CEC@ZIF-8 NPs while ROS inhibitors and caspase inhibitors reversed CEC@ZIF-8 NPs-induced apoptosis. Finally, CEC@ZIF-8 NPs also reduced the growth rate of xenograft tumors in mice without the systemic toxicity observed with cisplatin treatment.

CONCLUSIONS

The CEC@ZIF-8 nano-drug delivery system significantly enhanced the anti-cervical cancer effect of CEC both in vivo and in vitro, providing a more promising drug delivery system for clinical applications and tumor management. At the same time, this work demonstrates the clinical potential of CEC-loaded ZIF-8 nanoparticles for the selective destruction of tumor tissues.

The application and prospects of antimicrobial peptides in antiviral therapy

Antimicrobial peptides (AMPs) have broad-spectrum antimicrobial activity, enabling them to rapidly detect and eliminate targets. In addition, many AMPs are natural peptides, making them promising candidates for therapeutic drugs. This review discusses the basic properties and mechanisms of action of AMPs, highlighting their ability to disrupt microbial membranes and modulate host immune responses. It also reviews the current state of research into using AMPs against various viral infections, focusing on their therapeutic potential against viruses that contribute to the global health crisis. Despite promising developments, therapies based on AMPs still face challenges such as stability, toxicity, and production costs. In this text, we will discuss these challenges and the latest technological advances aimed at overcoming them. The combination of nanotechnology and bioengineering approaches offers new ways to enhance the delivery, efficacy, and safety of AMPs. We emphasize the importance of further research to fully exploit the potential of AMPs in antiviral therapy, advocating a multifaceted approach that includes optimizing clinical use and exploring synergies with existing antiviral drugs.

Current status of development and biomedical applications of peptide-based antimicrobial hydrogels

Microbial contamination poses a serious threat to human life and health. Through the intersection of material science and modern medicine, advanced bionic hydrogels have shown great potential for biomedical applications due to their unique bioactivity and ability to mimic the extracellular matrix environment. In particular, as a promising antimicrobial material, the synthesis and practical biomedical applications of peptide-based antimicrobial hydrogels have drawn increasing research interest. The synergistic effect of peptides and hydrogels facilitate the controlled release of antimicrobial agents and mitigation of their biotoxicity while achieving antimicrobial effects and protecting the active agents from degradation. This review reports on the progress and trends of researches in the last five years and provides a brief outlook, aiming to provide theoretical background on peptide-based antimicrobial hydrogels and make suggestions for future related work.