Roles of zinc in cancers: From altered metabolism to therapeutic applications

Encapsulated mitochondria to reprogram the metabolism of M2-type macrophages for anti-tumor therapy

M2-type macrophages (M2Φ) play a pro-tumorigenic role and are closely associated with tumor development, where metabolic dysregulation exacerbates the immunosuppressive tumor microenvironment and fosters tumor growth. Mitochondria serve as the regulatory center of cellular metabolism, yet effective methods to modulate M2Φ mitochondria within the tumor microenvironment remain lacking. In this study, we developed a technique utilizing the bio-encapsulation of mitochondria in Zeolitic Imidazolate Framework-8 (ZiF-8), referred to as Mito@ZiF-8. Our findings demonstrated that this coating protects intact mitochondria and preserves their bioactivity over an extended period after isolation. We successfully delivered Mito@ZiF-8 into M2Φ, which inhibited the secretion of pro-inflammatory factors, promoted the release of anti-inflammatory factors, and reprogrammed M2Φ metabolism. This innovative approach has the potential to reduce breast cancer cell metastasis and enhance sensitivity to chemotherapy drugs such as 6-thioguanine, cisplatin, and doxorubicin (Dox). Mito@ZiF-8 aims to reprogram the M2Φ microenvironment to support anti-tumor therapies, offering a novel strategy for improving the effectiveness of breast cancer treatment.

Tailored Metal-Based Catalysts: A New Platform for Targeted Anticancer Therapies

Innovative strategies for targeted anticancer therapies have gained significant momentum, with metal complexes emerging as tunable catalysts for more effective and safer treatments. Rational design and engineering of metal complexes enable the development of tailored molecular structures optimized for precision oncology. The strategic incorporation of metal complex catalysts within combinatorial therapies amplifies their anticancer properties. This perspective highlights the advancements in synthetic strategies and rational design since 2019, showing how tailored metal catalysts are optimized by designing structures to release or in situ synthesize active drugs, leveraging the target-specific characteristics to develop more precise cancer therapies. This review explores metal-based catalysts, including those conjugated with biomolecules, nanostructures, and metal-organic frameworks (MOFs), highlighting their catalytic activity in biological environments and their in vitro/in vivo performance. To sum up, the potential of metal complexes as catalysts to reshape the landscape of anticancer therapies and foster novel avenues for therapeutic advancement is emphasized.

Antineoplastics for treating Alzheimer's disease and dementia: Evidence from preclinical and observational studies

As the world population ages, there will be an increasing need for effective therapies for aging-associated neurodegenerative disorders, which remain untreatable. Dementia due to Alzheimer's disease (AD) is one of the leading neurological diseases in the aging population. Current therapeutic approaches to treat this disorder are solely symptomatic, making the need for new molecular entities acting on the causes of the disease extremely urgent. One of the potential solutions is to use compounds that are already in the market. The structures have known pharmacokinetics, pharmacodynamics, toxicity profiles, and patient data available in several countries. Several drugs have been used successfully to treat diseases different from their original purposes, such as autoimmunity and peripheral inflammation. Herein, we divulge the repurposing of drugs in the area of neurodegenerative diseases, focusing on the therapeutic potential of antineoplastics to treat dementia due to AD and dementia. We briefly touch upon the shared pathological mechanism between AD and cancer and drug repurposing strategies, with a focus on artificial intelligence. Next, we bring out the current status of research on the development of drugs, provide supporting evidence from retrospective, clinical, and preclinical studies on antineoplastic use, and bring in new areas, such as repurposing drugs for the prion-like spreading of pathologies in treating AD.

Blood and Serum Se and Zn Levels and 10-Year Survival of Patients after a Diagnosis of Kidney Cancer

The aim of the project was to evaluate the association between selenium (Se) and zinc (Zn) levels in blood and serum and kidney cancer mortality. In a prospective group of 284 consecutive, unselected patients with kidney cancer, we evaluated their 10-year survival rate in relation to the levels of Se and Zn in their blood and serum. Micronutrient levels were measured using an inductively coupled plasma mass spectrometer. Patients were divided into quartiles based on the distribution of Se and Zn levels arranged in increasing order. The following variables were taken into account in the multivariable models: age at diagnosis, gender, smoking, type of surgery and histopathological examination results. We observed a statistically significant association of all-cause mortality when subgroups with low blood selenium levels were compared to patients with high selenium levels (HR = 7.74; p < 0.001). We found, in addition, that this correlation was much stronger when only men were assessed (HR = 11.6; p < 0.001). We did not find a statistically significant association for zinc alone. When we combined selenium and zinc levels (SeQI-ZnQI vs. SeQIV-ZnQIV), we observed the hazard ratio for kidney cancer death to be 12.4; p = 0.016. For patients in the highest quartile of blood zinc/selenium ratio, compared to those in the lowest, the HR was 2.53; p = 0.008. Our study suggests that selenium levels, combined selenium and zinc levels (SeQI-ZnQI vs. SeQIV-ZnQIV) and zinc-to-selenium ratio (Zn/Se) are attractive targets for clinical trials aimed at improving the survival of kidney cancer patients.

Analyzing antimicrobial activity of ZnO/FTO, Sn-Cu-doped ZnO/FTO thin films: Production and characterizations

In the developing field of nanotechnology, ZnO (zinc oxide) based semiconductor samples have emerged as the foremost choice due to their immense potential for advancing the development of cutting-edge nanodevices. Due to its excellent chemical stability, low cost, and non-toxicity to biological systems, it is also utilized in various investigations. In this study, the successive ionic layer adsorption and reaction (SILAR) method was used to generate FTO (fluorine-doped tin oxide)/ZnO, and tin (Sn)-copper (Cu)-doped ZnO thin films at varying concentrations on FTO substrates. After being stacked 40 times in varying concentrations on the FTO substrate, FTO/ZnO thin films and Sn-Cu-doped thin films were annealed at 300°C. Using Scanning Electron Microscopy (SEM) Energy Dispersive Spectroscopy-(EDS), the agar diffusion test, and the viability cell counting method, the minimum inhibitory concentration, structural properties, surface morphology, antibacterial properties, bacterial adhesion, and survival organism count of FTO/ZnO thin films and Sn-Cu-doped thin films were investigated. Both doped and FTO/ZnO films with varying Sn-Cu concentrations expanded harmonically on the FTO substrate, according to the SEM-EDS investigation. The doping concentration affected their morphological properties, causing changes depending on the doping level. Antibacterial activity was observed in the powder metals, but no antibacterial activity was found in the thin film form. The highest adhesion rate of bacterial organisms on the produced samples was observed when the FTO/ZnO/Sn-Cu doping rate was 1%. In addition, the lowest adhesion rate was observed when the FTO/ZnO/Sn-Cu additive ratio was 3%. RESEARCH HIGHLIGHTS: ZnO based semiconductors highlight significant potential in advancing nanodevice technology due to their chemical stability, cost-effectiveness, and biocompatibility. Employing the SILAR method, the study innovatively fabricates FTO/ZnO and Sn-Cu-doped ZnO thin films on FTO substrates, exploring a novel approach in semiconductor manufacturing. Post annealing at 300°C, the research examines the structural and surface morphological changes in the films, contributing to the understanding of semiconductor behavior under varying conditions. The study delves into the antibacterial properties of ZnO thin films, offering insights into the potential biomedical applications of these materials. SEM-EDS analysis reveals that doping concentrations crucially influence the morphological properties of ZnO thin films, shedding light on the optimization of semiconductor performance. Findings indicate a specific doping rate (1% Sn-Cu) enhances bacterial adhesion, while a 3% additive ratio minimizes it, suggesting implications for biomedical device engineering and antibacterial surface design.

A Diet Lacking Selenium, but Not Zinc, Copper or Manganese, Induces Anticancer Activity in Mice with Metastatic Cancers

Selenium, zinc, copper, and manganese are essential components of antioxidant enzymes involved in the elimination of reactive oxygen species (ROS). Given that cancer cells produce high levels of ROS and the accumulation of ROS can lead to cell death, cancer cells may be susceptible to strategies that reduce ROS elimination. In this work, we prepared several artificial diets that contained normal carbohydrate, protein, and lipid levels but lacked selenium, zinc, copper, or manganese. The anticancer activity of these diets was examined in a metastatic ovarian cancer model, established by injecting ID8 Trp53-/- murine ovarian cancer cells into the peritoneal cavity of C57BL/6JRj mice. Treatments started 15 days later and consisted of replacing a normal diet with one of the artificial diets for several weeks. A significant improvement in mice survival was observed when the normal diet was replaced with the selenium-free diet. Diets lacking zinc, copper, or manganese showed no significant impact on mice survival. All diets were very well tolerated. The anticancer efficacy of a diet lacking selenium was confirmed in mice with metastatic colon cancer and in mice with metastatic triple-negative breast cancer. These results suggest that diets lacking selenium hold potential for the treatment of metastatic cancers.

Modulation of Metal Homeostasis for Cancer Therapy

Metal ions such as iron, zinc, copper, manganese, and calcium are essential for normal cellular processes, including DNA synthesis, enzyme activity, cellular signaling, and oxidative stress regulation. When the balance of metal homeostasis is disrupted, it can lead to various pathological conditions, including cancer. Thus, understanding the role of metal homeostasis in cancer has led to the development of anti-tumor strategies that specifically target the metal imbalance. Up to now, diverse small molecule-based chelators, ionophores, metal complexes, and metal-based nanomaterials have been developed to restore the normal balance of metals or exploit the dysregulation for therapeutic purposes. They hold great promise in inhibiting tumor growth, preventing metastasis, and enhancing the effectiveness of existing cancer therapies. In this review, we aim to provide a comprehensive summary of the strategies employed to modulate the homeostasis of iron, zinc, copper, manganese, and calcium for cancer therapy. Their modulation mechanisms for metal homeostasis are succinctly described, and their recent applications in the field of cancer therapy are discussed. At the end, the limitations of these approaches are addressed, and potential avenues for future developments are explored.

Iron metabolism: backfire of cancer cell stemness and therapeutic modalities

Cancer stem cells (CSCs), with their ability of self-renewal, unlimited proliferation, and multi-directional differentiation, contribute to tumorigenesis, metastasis, recurrence, and resistance to conventional therapy and immunotherapy. Eliminating CSCs has long been thought to prevent tumorigenesis. Although known to negatively impact tumor prognosis, research revealed the unexpected role of iron metabolism as a key regulator of CSCs. This review explores recent advances in iron metabolism in CSCs, conventional cancer therapies targeting iron biochemistry, therapeutic resistance in these cells, and potential treatment options that could overcome them. These findings provide important insights into therapeutic modalities against intractable cancers.