KRAS NF-κB is involved in the development of zinc resistance and reduced curability in prostate cancer

MT2A promotes angiogenesis in chronically ischemic brains through a copper-mitochondria regulatory mechanism

BACKGROUND

Approximately half of patients with chronic ischemic cerebrovascular disease (CICD) exhibit poor revascularization. Metallothionein 2 A (MT2A) has a high affinity for metal ions and is potentially capable of chelating toxic copper ions to alleviate the impairment of angiogenesis. Therefore, we hypothesized that MT2A could promote angiogenesis in chronically ischemic brains by neutralizing excessive copper ions during copper overload (CPO).

METHODS

We first collected dura matter (DM) samples from CICD patients and examined the expression of cuproptosis-related genes (DLAT, FDX1, and SDHB) to confirm the inhibitory effect of CPO on angiogenesis. Then, we treated human umbilical vein endothelial cells (HUVECs) with different concentrations of elesclomol and CuCl2 to determine the optimal concentration for inducing CPO. HUVEC activity and mitochondrial structure and function were detected to explore the ability of MT2A to alleviate CPO-induced damage. Finally, a rat model of 2-vessel occlusion plus encephalo-myo-synangiosis (2VO + EMS) with CPO was established to test the proangiogenic effect of MT2A through the copper-mitochondria regulatory mechanism in chronically ischemic brains.

RESULTS

Compared with those from Matsushima grade A patients, DM samples from Matsushima grade C patients presented significantly greater DLAT and FDX1 expression and significantly lower SDHB expression. The optimal drug concentration for inducing CPO was subsequently determined, and in vitro experiments revealed that HUVEC activity was significantly decreased in the CPO group under hypoxic culture, accompanied by increased DLAT oligomerization, decreased SDHB expression, increased HSP70 expression. Moreover, significantly more common mitochondrial aberrations and significantly lower mitochondrial activity were detected in the CPO group compare with the control group. Additionally, MT2A overexpression alleviated CPO-induced mitochondrial dysfunction and cytotoxicity, improving HUVEC viability. In vivo, a CPO rat model was established, and CPO inhibited cerebral angiogenesis in 2VO + EMS model rats. Moreover, significantly greater CD31 expression, less DLAT accumulation, more mitochondria, and fewer mitochondrial abnormalities were observed in the CPOMT2A+ group than in the CPO group, accompanied by significantly improved cerebral blood perfusion and cognitive function.

CONCLUSION

MT2A can promote angiogenesis in chronically ischemic brains by neutralizing excessive copper ions and rescuing CPO-induced mitochondrial dysfunction.

Dextran-Graft-Polyacrylamide/Zinc Oxide Nanoparticles Inhibit of Cancer Cells in vitro and in vivo

Introduction

Tumor drug resistance and systemic toxicity are major challenges of modern anticancer therapy. Nanotechnology makes it possible to create new materials with the required properties for anticancer therapy.

Methods

In this research, Dextran-graft-Polyacrylamide/ZnO nanoparticles were used. The study was carried out using prostate (DU-145, LNCaP, PC-3), breast (MDA-MB-231, MCF-7, MCF-7 Dox) cancer cells and non-malignant (MAEC, BALB/3T3 clone A31) cells. Zinc was visualized with fluorescence in vitro and in vivo. ROS and apoptotic markers were identified by cytometry. Zinc accumulation and histopathological changes in the tumor, liver, kidney, and spleen were evaluated in a rat model.

Results

ZnO nanoparticles dissociation and release of Zn2+ into the cytosol occurs in 2-3 hours for cancerous and non-cancerous cells. ROS upregulation was detected in all cells. For non-malignant cells, the difference between the initial ROS level was insignificant. The rate of carbohydrate metabolism in cancer cells was reduced by nanosystems. Zinc level in the tumor was upregulated by 25% and 39% after treatment with nanosystems and doxorubicin combined, respectively. The tumor Walker-256 carcinosarcoma volume was reduced twice following mono-treatment with the nanocomplex and 65-fold lower when the nanocomplex was combined with doxorubicin compared with controls. In the liver, kidney and spleen, the zinc level increased by 10-15% but no significant pathological alterations in the tissues were detected.

Conclusion

D-PAA/ZnO NPs nanosystems were internalized by prostate, breast cancer cells and non-malignant cells via endocytosis after short time, but cytotoxicity against non-cancer cells were significantly lower in vitro and in vivo. D-PAA/ZnO NPs nanocomplex efficiently promoted cell death of tumor cells without showing cytotoxicity against non-malignant cells making it a promising anti-cancer agent.

Long-term zinc treatment alters the mechanical properties and metabolism of prostate cancer cells

The failure of intracellular zinc accumulation is a key process in prostate carcinogenesis. Although prostate cancer cells can accumulate zinc after long-term exposure, chronic zinc oversupply may accelerate prostate carcinogenesis or chemoresistance. Because cancer progression is associated with energetically demanding cytoskeletal rearrangements, we investigated the effect of long-term zinc presence on biophysical parameters, ATP production, and EMT characteristics of two prostate cancer cell lines (PC-3, 22Rv1). Prolonged exposure to zinc increased ATP production, spare respiratory capacity, and induced a response in PC-3 cells, characterized by remodeling of vimentin and a shift of cell dry mass density and caveolin-1 to the perinuclear region. This zinc-induced remodeling correlated with a greater tendency to maintain actin architecture despite inhibition of actin polymerization by cytochalasin. Zinc partially restored epithelial characteristics in PC-3 cells by decreasing vimentin expression and increasing E-cadherin. Nevertheless, the expression of E-cadherin remained lower than that observed in predominantly oxidative, low-invasive 22Rv1 cells. Following long-term zinc exposure, we observed an increase in cell stiffness associated with an increased refractive index in the perinuclear region and an increased mitochondrial content. The findings of the computational simulations indicate that the mechanical response cannot be attributed exclusively to alterations in cytoskeletal composition. This observation suggests the potential involvement of an additional, as yet unidentified, mechanical contributor. These findings indicate that long-term zinc exposure alters a group of cellular parameters towards an invasive phenotype, including an increase in mitochondrial number, ATP production, and cytochalasin resistance. Ultimately, these alterations are manifested in the biomechanical properties of the cells.

Zinc-Mediated Endoplasmic Reticulum Stress and Metallothionein Alleviate Arsenic-Induced Cardiotoxicity in Cyprinus Carpio

Arsenic (As) is a natural component of the Earth's crust, and its inorganic form is highly toxic. The problem of As pollution in water is extremely urgent, and its impact on aquatic organisms should be widely considered. Here, 120 common carp were selected as the test subjects and were exposed to environmentally relevant concentrations of As (2.83 mg L- 1) for 30 days. Histomorphological observations showed the adverse effects of As on the heart: irregular arrangement of myocardial fibers, rupture of muscle fiber bundles, inflammatory infiltration, and hemorrhages. Mechanistically, abnormal expression of factors related to As-induced inflammation (TLR4/MYD88/NF-κB pathway), endoplasmic reticulum stress (CHOP, GRP78, ATF6, PERK, IRE1) and oxidative stress (SOD, CAT, Nrf2, HO-1) was observed. Then, we tried to find a protective agent against As-induced myocardial injury. As one of the important metal elements for maintaining cell growth and immunity, zinc (Zn, 1 mg L- 1) significantly alleviated the pathological abnormalities induced by As, and the changes in physiological and biochemical indices in response to As exposure were significantly alleviated by Zn administration, which was accompanied by the restoration of metallothionein (ZIP8, Znt1, Znt5, Znt7) and heat shock protein (HSP60, HSP70, HSP90) expression. These results suggest for the possibilty of developing Zn as a candidate therapeutic agent for As induced aquatic toxicology.

Toenail zinc and risk of prostate cancer in the MCC-Spain case-control study

BACKGROUND

Some researchers have suggested that zinc (Zn) could reduce the risk of prostate cancer (PC). However, research from observational studies on the relationship between PC risk and biomarkers of Zn exposure shows conflicting results.

OBJECTIVES

To evaluate the association between toenail Zn and PC, considering tumour extension and aggressiveness, along with a gene-environment approach, exploring the interaction of individual genetic susceptibility to PC in the relationship between toenail Zn and PC.

METHODS

In MCC-Spain study we invited all incident PC cases diagnosed in the study period (2008-2013) and recruited randomly selected general population controls. In this report we included 913 cases and 1198 controls with toenail Zn determined by inductively coupled plasma mass spectrometry. To measure individual genetic susceptibility, we constructed a polygenic risk score based on known PC-related single nucleotide polymorphisms. The association between toenail Zn and PC was explored with mixed logistic and multinomial regression models.

RESULTS

Men with higher toenail Zn had higher risk of PC (OR quartile 4 vs.1: 1.41; 95% CI: 1.07-1.85). This association was slightly higher in high-grade PC [(ISUP≤2 Relative risk ratio (RRR) quartile 4 vs.1: 1.36; 1.01-1.83) vs. (ISUP3-5 RRR quartile 4 vs.1: 1.64; 1.06-2.54)] and in advanced tumours [(cT1-cT2a RRR quartile 4 vs.1: 1.40; 95% CI: 1.05-1.89) vs. (cT2b-cT4 RRR quartile 4 vs.1: 1.59; 1.00-2.53)]. Men with lower genetic susceptibility to PC were those at higher risk of PC associated with high toenail Zn (OR quartile 4 vs.1: 2.18; 95% CI: 1.08-4.40).

DISCUSSION

High toenail Zn levels were related to a higher risk for PC, especially for more aggressive or advanced tumours. This effect was stronger among men with a lower genetic susceptibility to PC.

The Role of the NF-kB Pathway in Intracranial Aneurysms

The pathophysiology of intracranial aneurysms (IA) has been proven to be closely linked to hemodynamic stress and inflammatory pathways, most notably the NF-kB pathway. Therefore, it is a potential target for therapeutic intervention. In the present review, we investigated alterations in the vascular smooth muscle cells (VSMCs), extracellular matrix, and endothelial cells by the mediators implicated in the NF-kB pathway that lead to the formation, growth, and rupture of IAs. We also present an overview of the NF-kB pathway, focusing on stimuli and transcriptional targets specific to IAs, as well as a summary of the current strategies for inhibiting NF-kB activation in IAs. Our report adds to previously reported data and future research directions for treating IAs using compounds that can suppress inflammation in the vascular wall.

Impact of Zinc Transport Mechanisms on Embryonic and Brain Development

The trace element zinc (Zn) binds to over ten percent of proteins in eukaryotic cells. Zn flexible chemistry allows it to regulate the activity of hundreds of enzymes and influence scores of metabolic processes in cells throughout the body. Deficiency of Zn in humans has a profound effect on development and in adults later in life, particularly in the brain, where Zn deficiency is linked to several neurological disorders. In this review, we will summarize the importance of Zn during development through a description of the outcomes of both genetic and early dietary Zn deficiency, focusing on the pathological consequences on the whole body and brain. The epidemiology and the symptomology of Zn deficiency in humans will be described, including the most studied inherited Zn deficiency disease, Acrodermatitis enteropathica. In addition, we will give an overview of the different forms and animal models of Zn deficiency, as well as the 24 Zn transporters, distributed into two families: the ZIPs and the ZnTs, which control the balance of Zn throughout the body. Lastly, we will describe the TRPM7 ion channel, which was recently shown to contribute to intestinal Zn absorption and has its own significant impact on early embryonic development.

Sensors for diagnosis of prostate cancer: Looking beyond the prostate specific antigen

Prostate cancer represents one of the most common forms of cancer affecting men across the globe. Due to late diagnosis of this disease, the mortality of this condition is very high. Conventional diagnostic methods like the direct rectal examination are uncomfortable and, in most cases, delayed, and further confirmation is required with biopsies and Gleason score. The most common biomarker approved by the FDA (United States Food and Drug Administration) is the prostate specific antigen (PSA) that is detected by conventional biochemical assays which require expensive reagents, is time-consuming and more often is only indicative and cannot be considered confirmative as it is susceptible to erroneous conclusions. The prostate health index employs quantification of PSA in its free and bound forms to enumerate the risk of prostate cancer and has found acceptance with clinicians though the methods used to determine these quantities are slow and require additional sensitivity. Search for novel biomarkers other than PSA has resulted in the identification of several promising candidates. However, their detection is still heavily dependent upon conventional biochemical assays that retain the challenges of being time-consuming, poorly sensitive and expensive. Development of specific sensor technologies integrating nanomaterials offers a viable alternative for rapid and sensitive determination of these non-PSA markers. This review summarizes the major advances in the development of sensors for diagnosis of prostate cancer using non-PSA markers. It also highlights some of the emerging paradigms in cancer diagnosis that may transform the diagnostic field in the context of prostate cancer.

Association of zinc level and polymorphism in MMP-7 gene with prostate cancer in Polish population

INTRODUCTION

Prostate cancer is one of the most commonly diagnosed malignancies among men in Western populations. Evidence reported in the literature suggests that zinc may be related to prostate cancer. In this study we evaluated the association of serum zinc levels and polymorphisms in genes encoding zinc-dependent proteins with prostate cancer in Poland.

METHODS

The study group consisted of 197 men affected with prostate cancer and 197 healthy men. Serum zinc levels were measured and 5 single nucleotide polymorphisms in MMP-1, MMP-2, MMP-7, MMP-13, MT2A genes were genotyped.

RESULTS

The mean serum zinc level was higher in prostate cancer patients than in healthy controls (898.9±12.01 μg/l vs. 856.6±13.05 μg/l, p<0.01). When compared in quartiles a significant association of higher zinc concentration with the incidence of prostate cancer was observed. The highest OR (OR = 4.41, 95%CI 2.07-9.37, p<0.01) was observed in 3rd quartile (>853.0-973.9 μg/l). Among five analyzed genetic variants, rs11568818 in MMP-7 appeared to be correlated with 2-fold increased prostate cancer risk (OR = 2.39, 95% CI = 1.19-4.82, p = 0.015).

CONCLUSION

Our results suggest a significant correlation of higher serum zinc levels with the diagnosis of prostate cancer. The polymorphism rs11568818 in MMP-7 gene was also associated with an increased prostate cancer risk in Poland.

Zinc ion dyshomeostasis increases resistance of prostate cancer cells to oxidative stress via upregulation of HIF1α

Zinc ions (Zn²⁺) are known to influence cell survival and proliferation. However the homeostatic regulation of Zn²⁺ and their role in prostate cancer (PC) progression is poorly understood. Therefore the subcellular distribution and uptake of Zn²⁺ in PC cells were investigated. Inductively coupled plasma mass spectroscopy and fluorescent microscopy with the Zn²⁺-specific fluorescent probe FluoZin-3 were used to quantify total and free Zn²⁺, respectively, in the normal prostate epithelial cell line (PNT1A) and three human PC cell lines (PC3, DU145 and LNCaP). The effects of Zn²⁺ treatment on proliferation and survival were measured in vitro using MTT assays and in vivo using mouse xenografts. The ability of Zn²⁺ to protect against oxidative stress via a HIF1α-dependent mechanism was investigated using a HIF1α knock-down PC3 model. Our results demonstrate that the total Zn²⁺ concentration in normal PNT1A and PC cells is similar, but PC3 cells contain significantly higher free Zn²⁺ than PNT1A cells (p < 0.01). PNT1A cells can survive better in the presence of high concentrations of Zn²⁺ than PC3 cells. Exposure to 10 µM Zn²⁺ over 72 hours significantly reduces PC3 cell proliferation in vitro but not in vivo. Zn²⁺ increases PC3 cell survival up to 2.3-fold under oxidative stress, and this protective effect is not seen in PNT1A cells or in a HIF1α-KD PC3 cell model. A state of Zn²⁺ dyshomeostasis exists in PC. HIF1α is an integral component of a Zn²⁺-dependent protective mechanism present in PC3 cells. This pathway may be clinically significant through its contribution to castrate-resistant PC survival.

Recent views of heavy metals as possible risk factors and potential preventive and therapeutic agents in prostate cancer

Prostate cancer is the most common cancer in men in many industrialized countries. A role for androgens in prostate tumor progression is well recognized, while estrogens may cooperate with androgens in prostate carcinogenesis. The incidence of prostate cancer is highly variable in the different countries, suggesting an important role of environmental factors. Heavy metals are common environmental contaminants and some of them are confirmed or suspected human carcinogens. Some metals are endowed with estrogenic and/or androgenic activities and may play a role as cancer risk factors through this mechanism. Moreover, prostate cancer may present alterations in the intracellular balance of trace metals, such as zinc and copper, which are involved in several regulatory proteins. Herein, we review the possible role of environmental heavy metals and of metal-dyshomeostasis in prostate cancer development and promotion as well as the potential use of some metals in the prevention and therapy of prostate cancer.

Amino Acid Profiling of Zinc Resistant Prostate Cancer Cell Lines: Associations With Cancer Progression

BACKGROUND

Failure in intracellular zinc accumulation is a key process in prostate carcinogenesis. Nevertheless, epidemiological studies of zinc administration have provided contradicting results. In order to examine the impact of the artificial intracellular increase of zinc(II) ions on prostate cancer metabolism, PNT1A, 22Rv1, and PC-3 prostatic cell lines-depicting different stages of cancer progression-and their zinc-resistant counterparts were used. To determine "benign" and "malignant" metabolic profiles, amino acid patterns, gene expression, and antioxidant capacity of these cell lines were assessed.

METHODS

Amino acid profiles were examined using an ion-exchange liquid chromatography. Intracellular zinc content was measured by atomic absorption spectrometry. Metallothionein was quantified using differential pulse voltammetry. The content of reduced glutathione was determined using high performance liquid chromatography coupled with an electrochemical detector. Cellular antioxidant capacity was determined by the ABTS test and gene expression analysis was performed by qRT-PCR.

RESULTS AND CONCLUSIONS

Long-term zinc treatment was shown to reroute cell metabolism from benign to more malignant type. Long-term application of high concentration of zinc(II) significantly enhanced cisplatin resistance, invasiveness, cellular antioxidant capacity, synthesis of glutathione, and expression of treatment resistance- and stemness-associated genes (SOX2, POU5F1, BIRC5). Tumorous cell lines universally displayed high accumulation of aspartate and sarcosine and depletion of essential amino acids. Increased aspartate/threonine, aspartate/methionine, and sarcosine/serine ratios were associated with cancer phenotype with high levels of sensitivity and specificity. Prostate 77: 604-616, 2017. © 2017 Wiley Periodicals, Inc.

Molecular response of 4T1-induced mouse mammary tumours and healthy tissues to zinc treatment

Breast cancer patients negative for the nuclear oestrogen receptor α have a particularly poor prognosis. Therefore, the 4T1 cell line (considered as a triple-negative model) was chosen to induce malignancy in mice. The aim of the present study was to assess if zinc ions, provided in excess, may significantly modify the process of mammary oncogenesis. Zn(II) ions were chosen because of their documented antitumour effects. Zn(II) is also known to induce the expression of metallothioneins (MT) and glutathion (GSH). A total dose of zinc sulphate per one gram of mouse weight used in the experiment was 0.15 mg. We studied the expression of MT1, MT2, TP53 and MTF-1 genes and also examined the effect of the tumour on antioxidant capacity. Tumour-free mice had significantly higher expression levels of the studied genes (p<0.003). Significant differences were also revealed in the gene expression between the tissues (p<0.001). The highest expression levels were observed in the liver. As compared to brain, lung and liver, significantly lower concentrations of MT protein were found in the primary tumour; an inverse trend was observed in the concentration of Zinc(II). In non-tumour mice, the amount of hepatic hydrosulphuryl groups significantly increased by the exposure to Zn(II), but the animals with tumour induction showed no similar trend. The primary tumour size of zinc-treated animals was 20% smaller (p=0.002); however, no significant effect on metastasis progression due to the zinc treatment was discovered. In conclusion, Zn(II) itself may mute the growth of primary breast tumours especially at their early stages.

Multimodal holographic microscopy: distinction between apoptosis and oncosis

Identification of specific cell death is of a great value for many scientists. Predominant types of cell death can be detected by flow-cytometry (FCM). Nevertheless, the absence of cellular morphology analysis leads to the misclassification of cell death type due to underestimated oncosis. However, the definition of the oncosis is important because of its potential reversibility. Therefore, FCM analysis of cell death using annexin V/propidium iodide assay was compared with holographic microscopy coupled with fluorescence detection - “Multimodal holographic microscopy (MHM)”. The aim was to highlight FCM limitations and to point out MHM advantages. It was shown that the annexin V+/PI− phenotype is not specific of early apoptotic cells, as previously believed, and that morphological criteria have to be necessarily combined with annexin V/PI for the cell death type to be ascertained precisely. MHM makes it possible to distinguish oncosis clearly from apoptosis and to stratify the progression of oncosis.