Dose dependent effects of cadmium on tumor angiogenesis

Low dose cadmium inhibits syndecan-4 expression in glycocalyx of glomerular endothelial cells

Cadmium (Cd) is one of the most polluting heavy metal in the environment. Cd exposure has been elucidated to cause dysfunction of the glomerular filtration barrier (GFB). However, the underlying mechanism remains unclear. C57BL/6J male mice were administered with 2.28 mg/kg cadmium chloride (CdCl2) dissolved in distilled water by oral gavage for 14 days. The expression of SDC4 in the kidney tissues was detected. Human renal glomerular endothelial cells (HRGECs) were exposed to varying concentrations of CdCl2 for 24 h. The mRNA levels of SDC4, along with matrix metalloproteinase (MMP)-2 and 9, were analyzed by quantitative PCR. Additionally, the protein expression levels of SDC4, MMP-2/9, and both total and phosphorylated forms of Smad2/3 (P-Smad2/3) were detected by western blot. The extravasation rate of fluorescein isothiocyanate-dextran through the Transwell was used to evaluate the permeability of HRGECs. SB431542 was used as an inhibitor of transforming growth factor (TGF)-β signaling pathway to further investigate the role of TGF-β. Cd reduced SDC4 expression in both mouse kidney tissues and HRGECs. In addition, Cd exposure increased permeability and upregulated P-Smad2/3 levels in HRGECs. SB431542 treatment inhibited the phosphorylation of Smad2/3, Cd-induced SDC4 downregulation, and hyperpermeability. MMP-2/9 levels increased by Cd exposure was also blocked by SB431542, demonstrating the involvement of TGF-β/Smad pathway in low-dose Cd-induced SDC4 reduction in HRGECs. Given that SDC4 is an essential component of glycocalyx, protection or repair of endothelial glycocalyx is a potential strategy for preventing or treating kidney diseases associated with environmental Cd exposure.

Mechanisms of Heavy Metal Cadmium (Cd)-Induced Malignancy

The environmental pollution of cadmium is worsening, and its significant carcinogenic effects on humans have been confirmed. Cadmium can induce cancer through various signaling pathways, including the ERK/JNK/p38MAPK, PI3K/AKT/mTOR, NF-κB, and Wnt. It can also cause cancer by directly damaging DNA and inhibiting DNA repair systems, or through epigenetic mechanisms such as abnormal DNA methylation, LncRNA, and microRNA. However, the detailed mechanisms of Cd-induced cancer are still not fully understood and require further investigation.

Hypoxia-mediated activation of hypoxia-inducible factor-1α in triple-negative breast cancer: A review

Triple-negative breast cancer (TNBC) is a subtype of breast cancer (BC) that is highly aggressive and hypoxic compared with other subtypes. The role of hypoxia-inducible factor 1α (HIF-1α) as a key hypoxic transcription factor in oncogenic processes has been extensively studied. Recently, it has been shown that HIF-1α regulates the complex biological processes of TNBC, such as glycolysis, angiogenesis, invasion and metastasis, BC stem cells enrichment, and immune escape, to promote TNBC survival and development through the activation of downstream target genes. This article discusses the expression of the HIF-1α transcription factor in TNBC and the Hypoxia-mediated activation of hypoxia-inducible factor-1α in triple-negative BC. It offers a fresh approach to clinical research and treatment for TNBC.

Impact of Heavy Metals on Glioma Tumorigenesis

Recently, an increase in the incidence of brain tumors has been observed in the most industrialized countries. This event triggered considerable interest in the study of heavy metals and their presence in the environment (air, water, soil, and food). It is probable that their accumulation in the body could lead to a high risk of the onset of numerous pathologies, including brain tumors, in humans. Heavy metals are capable of generating reactive oxygen, which plays a key role in various pathological mechanisms. Alteration of the homeostasis of heavy metals could cause the overproduction of reactive oxygen species and induce DNA damage, lipid peroxidation, and the alteration of proteins. A large number of studies have shown that iron, cadmium, lead, nickel, chromium, and mercury levels were significantly elevated in patients affected by gliomas. In this study, we try to highlight a possible correlation between the most frequently encountered heavy metals, their presence in the environment, their sources, and glioma tumorigenesis. We also report on the review of the relevant literature.

Transition metals in angiogenesis - A narrative review

The aim of this paper is to offer a narrative review of the literature regarding the influence of transition metals on angiogenesis, excluding lanthanides and actinides. To our knowledge there are not any reviews up to date offering such a summary, which inclined us to write this paper. Angiogenesis describes the process of blood vessel formation, which is an essential requirement for human growth and development. When the complex interplay between pro- and antiangiogenic mediators falls out of balance, angiogenesis can quickly become harmful. As it is so fundamental, both its inhibition and enhancement take part in various diseases, making it a target for therapeutic treatments. Current methods come with limitations, therefore, novel agents are constantly being researched, with metal agents offering promising results. Various transition metals have already been investigated in-depth, with studies indicating both pro- and antiangiogenic properties, respectively. The transition metals are being applied in various formulations, such as nanoparticles, complexes, or scaffold materials. Albeit the increasing attention this field is receiving, there remain many unanswered questions, mostly regarding the molecular mechanisms behind the observed effects. Notably, approximately half of all the transition metals have not yet been investigated regarding potential angiogenic effects. Considering the promising results which have already been established, it should be of great interest to begin investigating the remaining elements whilst also further analyzing the established effects.

Cadmium exposure promotes ferroptosis by upregulating Heat Shock Protein 70 in vascular endothelial damage of zebrafish

Cadmium (Cd) exposure is a risk factor for endothelial dysfunction and cardiovascular disease. Ferroptosis is a type of cell death that relies on lipid peroxidation. Whether ferroptosis acts in Cd-induced vascular endothelial damage and the underlying mechanisms remain unclear. Herein, we found that Cd resulted in ferroptosis of vascular endothelial cells (ECs) in vivo and in vitro. In the visualized zebrafish embryos, Cd accumulated in vascular ECs, ROS and lipid peroxidation levels were increased, and the oxidoreductase system was disturbed after exposure. Moreover, Cd decreased Gpx4 in ECs and caused smaller mitochondria with increased membrane density. Accompanied by ferroptosis, the number of ECs and the area of the caudal venous plexus in zebrafish embryos were reduced, and the survival rate of HUVECs decreased. These effects were partially reversed by ferrostatin-1 and aggravated by erastin. Mechanistically, an excessive increase in Heat Shock Protein 70 (Hsp70) was identified by transcriptomics after Cd exposure. Inhibition of Hsp70 by VER-155008 or siRNA ameliorated Cd-induced ferroptosis, thereby alleviating endothelial injury. Furthermore, Hsp70 regulated Cd-induced ferroptosis by targeting multiple targets, including Gpx4, Fth1, Nrf2 and Acsl4. Our findings provide a new approach to investigating the endothelial damage of Cd and indicate that regulation of Hsp70 is an important target for alleviating this process.

Novel Metal Nanomaterials to Promote Angiogenesis in Tissue Regeneration

Angiogenesis-the formation of new blood vessels from existing blood vessels-has drawn significant attention in medical research. New techniques have been developed to control proangiogenic factors to obtain desired effects. Two important research areas are 1) understanding cellular mechanisms and signaling pathways involved in angiogenesis and 2) discovering new biomaterials and nanomaterials with proangiogenic effects. This paper reviews recent developments in controlling angiogenesis in the context of regenerative medicine and wound healing. We focus on novel proangiogenic materials that will advance the field of regenerative medicine. Specifically, we mainly focus on metal nanomaterials. We also discuss novel technologies developed to carry these proangiogenic inorganic molecules efficiently to target sites. We offer a comprehensive overview by combining existing knowledge regarding metal nanomaterials with novel developments that are still being refined to identify new nanomaterials.

Cadmium Exposure Affects Serum Metabolites and Proteins in the Male Guizhou Black Goat

Food safety and environmental pollution are the hotspots of general concern globally. Notably, long-term accumulation of trace toxic heavy metals, such as cadmium (Cd), in animals may endanger human health via the food chain. The mechanism of Cd toxicity in the goat, a popular farmed animal, has not been extensively investigated to date. Therefore, in this study, ten male goats (Nubian black goat × native black goat) were exposed to Cd via drinking water containing CdCl2 (20 mg Cd·kg-1·BW) for 30 days (five male goats per group). In this study, we used an integrated approach combining proteomics and metabolomics to profile proteins and metabolites in the serum of Cd-exposed goats. It was found that Cd exposure impacted the levels of 30 serum metabolites and 108 proteins. The combined proteomic and metabolomic analysis revealed that Cd exposure affected arginine and proline metabolism, beta-alanine metabolism, and glutathione metabolism. Further, antioxidant capacity in the serum of goats exposed to Cd was reduced. We identified CKM and spermidine as potential protein and metabolic markers, respectively, of early Cd toxicity in the goat. This study details approaches for the early diagnosis and prevention of Cd-poisoned goats.

A Human Cell-based Assay to Assess the Induction of Vasculature Formation for Non-genotoxic Carcinogenicity Testing Purposes: A Pilot Study

The induction of vasculature formation is proposed to be a significant mechanism behind the non-genotoxic carcinogenicity of a chemical. The vasculature formation model used in this study is based on the coculture of human primary HUVECs and hASCs. This model was used to develop an assay to assess the induction of vasculature formation. Three assay protocols, based on different conditions, were developed and compared in order to identify the optimal conditions required. Some serum supplements and growth factors were observed to be essential for initiating vasculature formation. Of the studied putative positive reference chemicals, aspartame, sodium nitrite, bisphenol A and nicotine treatment led to a clear induction of vasculature formation, but arsenic and cadmium treatment only led to a slight increase. This human cell-based assay has the potential to be used as one test within a next generation testing battery, to assess the non-genotoxic carcinogenicity of a chemical through the mechanism of vasculature formation induction.

Gold nanoparticles capped with L-glycine, L-cystine, and L-tyrosine: toxicity profiling and antioxidant potential

Biomolecules-based surface modifications of nanomaterials may yield effective and biocompatible nanoconjugates. This study was designed to evaluate gold nanoconjugates (AuNCs) for their altered antioxidant potential. Gold nanoparticles (AuNPs) and their conjugates gave SPR peaks in the ranges of 512-525 nm, with red or blueshift for different conjugates. Cys-AuNCs demonstrated enhanced (p < 0.05) and Gly-AuNCs (p > 0.05) displayed reduced DPPH activity. Gly-AuNCs and Tyr-AuNCs displayed enhanced ferric-reducing power and hydrogen peroxide scavenging activity, respectively. Cadmium-intoxicated mice were exposed to gold nanomaterials, and the level of various endogenous parameters, i.e., CAT, GST, SOD, GSH, and MTs, was evaluated. GSH and MTs in liver tissues of the cadmium-exposed group (G2) were elevated (p < 0.05), while other groups showed nonsignificance deviations than the control group. It is concluded that these nanoconjugates might provide effective nanomaterials for biomedical applications. However, more detailed studies for their safety profiling are needed before their practical applications.

Novel considerations on EGFR-based therapy as a contributor to cancer cell death in NSCLC

Epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitors (TKIs) represented by gefitinib and erlotinib are widely used in treating non-small cell lung cancer (NSCLC). However, acquired resistance to EGFR-TKI treatment remains a clinical challenge. In recent years, emerging research investigated in EGFR-TKI-based combination therapy regimens, and remarkable achievements have been reported. This article focuses on EGFR-TKI-based regimens, reviews the standard and novel application of EGFR targets, and summarizes the mechanisms of EGFR-TKI combinations including chemotherapy, anti-vascular endothelial growth factor monoclonal antibodies, and immunotherapy in the treatment of NSCLC. Additionally, we summarize clinical trials of EGFR-TKI-based combination therapy expanding indications to EGFR mutation-negative lung malignancies. Moreover, novel strategies are under research to explore new drugs with good biocompatibility. Nanoparticles encapsulating non-coding RNA and chemotherapy of new dosage forms drawn great attention and showed promising prospects in effective delivery and stable release. Overall, as the development of resistance to EGFR-TKIs treatment is inevitable in most of the cases, further research is needed to clarify the underlying mechanism of the resistance, and to evaluate and establish EGFR-TKI combination therapies to diversify the treatment landscape for NSCLC.

Toxic mechanisms of cadmium and exposure as a risk factor for oral and gastrointestinal carcinomas

Incidence and mortality rates of gastrointestinal (GI) and oral cancers are among the highest in the world, compared to other cancers. GI cancers include esophageal, gastric, colon, rectal, liver, and pancreatic cancers, with colorectal cancer being the most common. Oral cancer, which is included in the head and neck cancers category, is one of the most important causes of death in India. Cadmium (Cd) is a toxic element affecting humans and the environment, which has both natural and anthropogenic sources. Generally, water, soil, air, and food supplies are reported as some sources of Cd. It accumulates in organs, particularly in the kidneys and liver. Exposure to cadmium is associated with different types of health risks such as kidney dysfunction, cardiovascular disease, reproductive dysfunction, diabetes, cerebral infarction, and neurotoxic effects (Parkinson's disease (PD) and Alzheimer's disease (AD)). Exposure to Cd is also associated with various cancers, including lung, kidney, liver, stomach, hematopoietic system, gynecologic and breast cancer. In the present study, we have provided and summarized the association of Cd exposure with oral and GI cancers.

Epigenetic Regulation in Chromium-, Nickel- and Cadmium-Induced Carcinogenesis

Environmental and occupational exposure to heavy metals, such as hexavalent chromium, nickel, and cadmium, are major health concerns worldwide. Some heavy metals are well-documented human carcinogens. Multiple mechanisms, including DNA damage, dysregulated gene expression, and aberrant cancer-related signaling, have been shown to contribute to metal-induced carcinogenesis. However, the molecular mechanisms accounting for heavy metal-induced carcinogenesis and angiogenesis are still not fully understood. In recent years, an increasing number of studies have indicated that in addition to genotoxicity and genetic mutations, epigenetic mechanisms play critical roles in metal-induced cancers. Epigenetics refers to the reversible modification of genomes without changing DNA sequences; epigenetic modifications generally involve DNA methylation, histone modification, chromatin remodeling, and non-coding RNAs. Epigenetic regulation is essential for maintaining normal gene expression patterns; the disruption of epigenetic modifications may lead to altered cellular function and even malignant transformation. Therefore, aberrant epigenetic modifications are widely involved in metal-induced cancer formation, development, and angiogenesis. Notably, the role of epigenetic mechanisms in heavy metal-induced carcinogenesis and angiogenesis remains largely unknown, and further studies are urgently required. In this review, we highlight the current advances in understanding the roles of epigenetic mechanisms in heavy metal-induced carcinogenesis, cancer progression, and angiogenesis.

Dibutyl phthalate promotes angiogenesis in EA.hy926 cells through estrogen receptor-dependent activation of ERK1/2, PI3K-Akt, and NO signaling pathways

Dibutyl phthalate (DBP) is an endocrine disruptor that has been widely used in various products of human use. DBP exposure has been associated with reproductive and cardiovascular diseases and metabolic disorders. Although dysfunction of the vascular endothelium is responsible for many cardiovascular and metabolic diseases, little is known about the effects of DBP on human endothelium. In this study, we investigated the effect of three concentrations of DBP (10^-6, 10^-5, and 10^-4 M) on angiogenesis in human endothelial cell (EC) line EA.hy926 after acute exposure. Tube formation assay was used to investigate in vitro angiogenesis, whereas qRT-PCR was employed to measure mRNA expression. The effect of DBP on extracellular signal-regulated kinase 1/2 (ERK1/2), phosphatidylinositol 3-kinase (PI3K)-protein kinase B (Akt), and endothelial nitric oxide (NO) synthase (eNOS) activation was examined using Western blotting, whereas the Griess method was used to assess NO production. Results show that the 24-h-long exposure to 10^-4 M DBP increased endothelial tube formation, which was prevented by addition of U0126 (ERK1/2 inhibitor), wortmannin (PI3K-Akt inhibitor), and l-NAME (NOS inhibitor). Short exposure to 10^-4 M DBP (from 15 to 120 min) phosphorylated ERK1/2, Akt, and eNOS in different time points and increased NO production after 24 and 48 h of exposure. Application of nuclear estrogen receptor (ER) and G protein-coupled ER (GPER) inhibitors ICI 182,780 and G-15, respectively, abolished the DBP-mediated ERK1/2, Akt, and eNOS phosphorylation and increase in NO production. In this study, we report for the first time that DBP exerts a pro-angiogenic effect on human vascular ECs and describe the molecular mechanism involving ER- and GPER-dependent activation of ERK1/2, PI3K-Akt, and NO signaling pathways.

MicroRNAs: Novel players in the diagnosis and treatment of cancer cachexia (Review)

Cachexia denotes a complex metabolic syndrome featuring severe loss of weight, fatigue and anorexia. In total, 50-80% of patients suffering from advanced cancer are diagnosed with cancer cachexia, which contributes to 40% of cancer-associated mortalities. MicroRNAs (miRNAs) are non-coding RNAs capable of regulating gene expression. Dysregulated miRNA expression has been observed in muscle tissue, adipose tissue and blood samples from patients with cancer cachexia compared with that of samples from patients with cancer without cachexia or healthy controls. In addition, miRNAs promote and maintain the malignant state of systemic inflammation, while inflammation contributes to cancer cachexia. The present review discusses the role of miRNAs in the progression of cancer cachexia, and assess their diagnostic value and potential therapeutic value.

Histopathological evaluation of amino acid capped silver nanoconjugates in albino mice

Various molecules may modify the surface chemistry of commonly used nanomaterials (NMs), resulting in the synthesis of novel and safer NMs. The current study was delineated to evaluate the in vivo toxicity profiling of the silver nanoconjugates (AgNCs) conjugated with different amino acids. The L-glycine capped-AgNCs exhibited toxicity and caused tissue damage, while L-cystine- and L-tyrosine-capped AgNCs showed protective effects against cadmium-induced toxicity. L-cystine-capped AgNCs performed well as compared to other amino-acid AgNCs. The level of serum creatinine, alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase and blood urea increased (p < 0.05) in G2, G3 and G5 in comparison to G1 (control group), while an increase in bilirubin for G2 was statistically non-significant (p > 0.05). The ALT and AST elevated (p < 0.05) in G4; however, other serological parameters in G4 and G6 did not show any noticeable change in their values. Histological analysis showed disturbed and deformed cellular structures in liver and kidney tissues of G2, G3 and G5. However, G4 and G6 samples demonstrated minute changes in comparison to G1. It is concluded that L-cystine- and L-tyrosine-capped AgNCs exhibited protective effects and should be tested further for developing safer nanoconjugates for biomedical uses.

Hypoxia Inhibits Proliferation of Human Dermal Lymphatic Endothelial Cells via Downregulation of Carcinoembryonic Antigen-related Cell Adhesion Molecule 1 Expression

OBJECTIVE

Lymphatic endothelial cell (LEC) proliferation is essential for lymphangiogenesis. Hypoxia induces lymphangiogenesis, but it directly inhibits LEC proliferation and the underlying mechanisms have not been fully understood. The aim of this study was to investigate the role of carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1) in hypoxia-repressed LEC proliferation.

METHODS

Human dermal lymphatic endothelial cells (HDLECs) were cultured under normoxic or hypoxic conditions, and cell proliferation was determined using MTT or CCK-8 assays. CEACAM1 expression was silenced by siRNA transfection. Activation of mitogen-activated protein kinases (MAPKs) was examined by Western blotting and blocked by specific inhibitors.

RESULTS

Under hypoxia, HDLECs proliferation was suppressed and CEACAM1 expression was downregulated. Silence of CEACAM1 in normoxia inhibited HDLECs proliferation and did not further decrease proliferation in HDLECs in response to hypoxia, suggesting that CEACAM1 may mediate hypoxia-induced inhibition of HDLECs proliferation. In addition, silence of CEACAM1 increased phosphorylation of MAPK molecules: extracellular signal-regulated kinase (ERK), p38 MAPK and Jun N-terminal kinase (JNK) in HDLECs. However, only inhibition of the JNK pathway rescued the reduction of HDLEC proliferation induced by CEACAM1 silence.

CONCLUSION

Our results suggested that hypoxia downregulates CEACAM1 expression by activation of the JNK pathway, leading to inhibition of HDLEC proliferation. These findings may help to understand the mechanisms of LEC-specific response to hypoxia and develop novel therapies for pathological lymphangiogenesis.

Concentration of heavy metals and rare earth elements in patients with brain tumours: Analysis in tumour tissue, non-tumour tissue, and blood

Inorganic elements have been associated with brain tumours for long. The blood concentration of 47 elements was assessed by ICP-MS in 26 brain tumour patients and 21 healthy subjects from Bucharest (Romania). All 47 elements were detected in the brain tumour tissue, and 22 were detected in > 80% of samples; this implies that these elements can cross the blood-brain barrier. Median blood levels of cadmium, lead, and nickel were higher than the reference values (1.14, 53.3, and 2.53 ng/mL). Gadolinium and tantalum showed significantly higher concentrations among cases. We observed considerable differences and different profiles of the presence of inorganic elements between the tumour and non-tumour brain tissue and between tissue from the primary tumour and tissue from brain metastasis. Our data suggest that similar to heavy metals, other elements - commonly used in high tech devices and rare earth elements - can also influence brain tumour.

Cadmium Exposure and Testis Susceptibility: a Systematic Review in Murine Models

It is known that cadmium induces damage to the testis. However, the significant cadmium impact on the testicular architecture and the mechanisms involved in this process are not clear. Besides, the relationship between dose, route, and time of exposure and injuries remains poorly understood. Thus, we aimed to assess whether cadmium exposure in any dose, route, and time of exposure causes significant alteration in the testicular tissue of murine models, as well as the main mechanisms involved. We performed a structured search on the Medline/PubMed and Scopus databases to retrieve studies published until September 2018. The results were organized into an Adverse Outcome Pathway (AOP) framework. Also, a bias analysis of included studies was performed. We included 37 studies, and most of them identified significant histopathologies in both tubule and intertubule regarding routes, in a dose- and time-dependent manner. The damages were observed after the first hours of exposure, mainly vascular damages suggesting that vasculature failure is the primary mechanism. The AOP showed that potential molecular initiating events may mimic and interfere with essential elements disrupting proteins (structural and antioxidants), change in the oxidative phosphorylation enzyme activities, and gene expression alteration, which lead to reproductive failure (adverse outcome). Analysis of methodological quality showed that the current evidence is at high risk of bias. Despite the high risk of bias, cadmium triggers significant lesions in the testis of murine models, regarding routes, in a dose- and time-dependent manner, mainly due to vascular changes. Therefore, cadmium is a risk factor for male reproductive health.

Cadmium-induced dysfunction of the blood-brain barrier depends on ROS-mediated inhibition of PTPase activity in zebrafish

Increasing evidence has demonstrated that cadmium accumulation in the blood increases the risk of neurological diseases. However, how cadmium breaks through the blood-brain barrier (BBB) and is transferred from the blood circulation into the central nervous system is still unclear. In this study, we examined the toxic effect of cadmium chloride (CdCl₂) on the development and function of BBB in zebrafish. CdCl₂ exposure induced cerebral hemorrhage, increased BBB permeability and promoted abnormal vascular formation by promoting VEGF production in zebrafish brain. Furthermore, in vivo and in vitro experiments showed that CdCl₂ altered cell-cell junctional morphology by disrupting the proper localization of VE-cadherin and ZO-1. The potential mechanism involved in the inhibition of protein tyrosine phosphatase (PTPase) mediated by cadmium-induced ROS was confirmed with diphenylene iodonium (DPI), a ROS production inhibitor. Together, these data indicate that BBB is a critical target of cadmium toxicity and provide in vivo etiological evidence of cadmium-induced neurovascular disease in a zebrafish BBB model.

Oncogenic transformation of human benign prostate hyperplasia with chronic cadmium exposure

Experimentally, it has been proved that cadmium served as an effective carcinogen and able to induce tumors in rodents in a dose-specific manner. However, systemic evaluation of cadmium exposure for the transformation of prostatic hyperplasia into prostate cancer (PCa) is still unclear. In the present study, an attempt has been made to establish cadmium-induced human prostate carcinogenesis using an in vitro model of BPH cells. Wide range of cadmium concentrations, i.e., 1 nM, 10 nM, 100 nM and 1μM, were chronically exposed to the human BPH cells for transformation into PCa and monitored using cell and molecular biology approaches. After eight weeks of exposure, the cells showed subtle morphological changes and shifts of cell cycle in the G2M phase. Significant increase in expression of prostatic genes AR, PSA, ER-β, and 5αR with increased nuclear localization of AR and pluripotency markers Cmyc, Klf4 indicated the carcinogenic effect of Cd. Further, the BPH cells exposed to Cd showed a substantial increase in the secretion of MMP-2 and MMP-9, influencing migratory potential of the cells along with decreased expression of the p63 protein which further strengthen the progression towards carcinogenesis and aggressive tumor studies. Data from the present study state that Cd exhibited marked invasiveness in BPH cells. These observations established a connecting link of BPH towards PCa pathogenesis. Further, the study will also help in investigating the intricate pathways involved in cancer progression.

Role of the PI3K/Akt pathway in cadmium induced malignant transformation of normal prostate epithelial cells

This study investigated the role of the PI3K/Akt pathway in cadmium (Cd) induced malignant transformation of normal prostate epithelial (PWR1E and RWPE1) cells. Both PWR1E and RWPE1 cells were exposed to 10 μM Cd for one year and designated as Cd-PWR1E and Cd-RWPE1. Cd-RWPE1 cells robustly formed tumors in athymic nude mice. Functionally, Cd-exposure induced tumorigenic attributes indicated by increased wound healing, migration and invasion capabilities in both cell lines. RT²-array analysis revealed many oncogenes including P110α, Akt, mTOR, NFKB1 and RAF were induced whereas tumor suppressor (TS) genes were attenuated in Cd-RWPE1. This was validated by individual quantitative-real-time-PCR at transcriptional and by immunoblot at translational levels. These results were consistent in Cd-PWR1E vs parental PWR1E cells. Gene Set Enrichment Analysis revealed that five prostate cancer (PCa) related pathways were enriched in Cd-exposed cells compared to their normal controls. These pathways include the KEGG- Pathways in cancer, Prostate Cancer Pathway, ERBB, Apoptosis and MAPK pathways. We selected up- and down-regulated genes randomly from the PI3K/Akt pathway array and profiled these in the TCGA/GDC prostate-adenocarcinoma (PRAD) patient cohort. An upregulation of oncogenes and downregulation of TS genes was observed in PCa compared to their normal controls. Taken together, our study reveals that the PI3K/Akt signaling is one of the main molecular pathways involved in Cd-driven transformation of normal prostate epithelial cells to malignant form. Understanding the molecular mechanisms involved in the Cd-driven malignant transformation of normal prostate cells will provide a significant insight to develop better therapeutic strategies for Cd-induced prostate cancer.

Chronic Low-Dose Exposure to Xenoestrogen Ambient Air Pollutants and Breast Cancer Risk: XENAIR Protocol for a Case-Control Study Nested Within the French E3N Cohort

Background

Breast cancer is the most frequent cancer in women in industrialized countries. Lifestyle and environmental factors, particularly endocrine-disrupting pollutants, have been suggested to play a role in breast cancer risk. Current epidemiological studies, although not fully consistent, suggest a positive association of breast cancer risk with exposure to several International Agency for Research on Cancer Group 1 air-pollutant carcinogens, such as particulate matter, polychlorinated biphenyls (PCB), dioxins, Benzo[a]pyrene (BaP), and cadmium. However, epidemiological studies remain scarce and inconsistent. It has been proposed that the menopausal status could modify the relationship between pollutants and breast cancer and that the association varies with hormone receptor status.

Objective

The XENAIR project will investigate the association of breast cancer risk (overall and by hormone receptor status) with chronic exposure to selected air pollutants, including particulate matter, nitrogen dioxide (NO2), ozone (O3), BaP, dioxins, PCB-153, and cadmium.

Methods

Our research is based on a case-control study nested within the French national E3N cohort of 5222 invasive breast cancer cases identified during follow-up from 1990 to 2011, and 5222 matched controls. A questionnaire was sent to all participants to collect their lifetime residential addresses and information on indoor pollution. We will assess these exposures using complementary models of land-use regression, atmospheric dispersion, and regional chemistry-transport (CHIMERE) models, via a Geographic Information System. Associations with breast cancer risk will be modeled using conditional logistic regression models. We will also study the impact of exposure on DNA methylation and interactions with genetic polymorphisms. Appropriate statistical methods, including Bayesian modeling, principal component analysis, and cluster analysis, will be used to assess the impact of multipollutant exposure. The fraction of breast cancer cases attributable to air pollution will be estimated.

Results

The XENAIR project will contribute to current knowledge on the health effects of air pollution and identify and understand environmental modifiable risk factors related to breast cancer risk.

Conclusions

The results will provide relevant evidence to governments and policy-makers to improve effective public health prevention strategies on air pollution. The XENAIR dataset can be used in future efforts to study the effects of exposure to air pollution associated with other chronic conditions.

International Registered Report Identifier (IRRID)

DERR1-10.2196/15167

Activation of the Erk/MAPK signaling pathway is a driver for cadmium induced prostate cancer

PURPOSE

Cadmium (Cd) is reported to be associated with carcinogenesis. The molecular mechanisms associated with Cd-induced prostate cancer (PCa) remain elusive.

MATERIALS AND METHODS

RWPE1, PWR1E and DU 145 cells were used. RT2 Profiler Array, real-time-quantitative-PCR, immunofluorescence, cell cycle, apoptosis, proliferation and colony formation assays along with Gene Set Enrichment Analysis (GSEA) were performed.

RESULT

Chronic Cd exposure of non-malignant RWPE1 and PWR1E cells promoted cell survival, proliferation and colony formation with inhibition of apoptosis. Even a two-week Cd exposure of PCa cell line (DU 145) significantly increased the proliferation and decreased apoptosis. RT2 profiler array of 84 genes involved in the Erk/MAPK pathway revealed induction of gene expression in Cd-RWPE1 cells compared to RWPE1. This was confirmed by individual TaqMan gene expression analysis in both Cd-RWPE1 and Cd-PWR1E cell lines. GSEA showed an enrichment of the Erk/MAPK pathway along with other pathways such as KEGG-ERBB, KEGG-Cell Cycle, KEGG-VEGF, KEGG-Pathways in cancer and KEGG-prostate cancer pathway. We randomly selected upregulated genes from Erk/MAPK pathway and performed profile analysis in a PCa data set from the TCGA/GDC data base. We observed upregulation of these genes in PCa compared to normal samples. An increase in phosphorylation of the Erk1/2 and Mek1/2 was observed in Cd-RWPE1 and Cd-PWR1E cells compared to parental cells, confirming that Cd-exposure induces activation of the Erk/MAPK pathway.

CONCLUSION

This study demonstrates that Erk/MAPK signaling is a major pathway involved in Cd-induced malignant transformation of normal prostate cells. Understanding these dominant oncogenic pathways may help develop optimal therapeutic strategies for PCa.

Chemical imaging and assessment of cadmium distribution in the human body

The scientific interest in cadmium (Cd) as a human health damaging agent has significantly increased over the past decades. However, particularly the histological distribution of Cd in human tissues is still scarcely defined. Using inductively coupled plasma-mass spectrometry (ICP-MS), we determined the concentration of Cd in 40 different human tissues of four body donors and provided spatial information by elemental imaging on the microscopic distribution of Cd in 8 selected tissues by laser ablation (LA)-ICP-MS. ICP-MS results show that Cd concentrations differ by a factor of 20 000 between different tissues. Apart from the well know deposits in kidney, bone, and liver, our study provides evidence that muscle and adipose tissue are underestimated Cd pools. For the first time, we present spatially resolved Cd distributions in a broad panel of human soft tissues. The defined histological structures are mirrored by sharp cut differences in Cd concentrations between neighboring tissue types, particularly in the rectum, testis, and kidneys. The spatial resolution of the Cd distribution at microscopic level visualized intratissue hot spots of Cd accumulation and is suggested as a powerful tool to elucidate metal based toxicity at histological level.

Chronic long-term exposure to cadmium air pollution and breast cancer risk in the French E3N cohort

Cadmium, due to its estrogen-like activity, has been suspected to increase the risk of breast cancer; however, epidemiological studies have reported inconsistent findings. We conducted a case-control study (4,059 cases and 4,059 matched controls) nested within the E3N French cohort study to estimate the risk of breast cancer associated with long-term exposure to airborne cadmium pollution, and its effect according to molecular subtype of breast cancer (estrogen receptor negative/positive [ER-/ER+] and progesterone receptor negative/positive [PR-/PR+]). Atmospheric exposure to cadmium was assessed using a Geographic Information System-based metric, which included subject's residence-to-cadmium source distance, wind direction, exposure duration and stack height. Adjusted odds ratios (OR) and 95% confidence intervals (CI) were estimated using conditional logistic regression. Overall, there was no significant association between cumulative dose of airborne cadmium exposure and the risk of overall, premenopausal and postmenopausal breast cancer. However, by ER and PR status, inverse associations were observed for ER- (ORQ5 vs. Q1  = 0.63; 95% CI: 0.41-0.95, ptrend  = 0.043) and for ER-/PR- breast tumors (ORQ4 vs. Q1  = 0.62; 95% CI: 0.40-0.95, ORQ5 vs. Q1  = 0.68; 95% CI: 0.42-1.07, ptrend  = 0.088). Our study provides no evidence of an association between exposure to cadmium and risk of breast cancer overall but suggests that cadmium might be related to a decreased risk of ER- and ER-/PR- breast tumors. These observations and other possible effects linked to hormone receptor status warrant further investigations.

Cadmium regulates von Willebrand factor and occludin expression in glomerular endothelial cells of mice in a TNF-α-dependent manner

Background: Cadmium (Cd) is an environmental pollutant that leads to nephrotoxicity. However, the mechanisms of Cd-induced glomerular injury have not been fully clarified. Von Willebrand factor (vWF) and occludin are important endothelial cell markers in renal vasculature. In this study, the effects of Cd on the vWF and occludin expression in mouse glomeruli was investigated.

Objectives: The goal of this study was to analyze the expression of von Willebrand factor and occludin in glomerular endothelial cells of tumor necrosis factor-α^−/− (TNF-α^−/−) mice after treatment with Cd.

Material and methods: C57BL6/J wild-type (WT) mice and TNF-α^−/− mice (n = 6) were treated with Cd, and the kidney tissues were collected. The expression of von Willebrand factor and occludin was detected by using quantitative real-time PCR, immunofluorescence, and immunohistochemistry. In vitro, Human umbilical vascular endothelial cells (HUVECs) were used to examine the regulatory role of TNF-α on expression of von Willebrand factor and occludin.

Results: We found that Cd significantly increases mRNA and protein expressions of von Willebrand factor and occludin in TNF-α^−/− mice, but not in WT mice. In vitro, Cd significantly increased mRNA and protein expression of von Willebrand factor and occludin in HUVECs with TNF-α small interfering RNA (siRNA) transfection.

Conclusions: These results suggest that TNF-α acts to balance homeostasis of glomerular endothelium after Cd treatments.

Role of B-Cell Lymphoma 2 Ovarian Killer (BOK) in Acute Toxicity of Human Lung Epithelial Cells Caused by Cadmium Chloride

Background

B-cell lymphoma 2 (BCL-2) ovarian killer (BOK) is a Bcl-2 family member with sequence homology to pro-apoptotic BAX and BAK, but its physiological and pathological roles remain largely unclear. Exposure of cells to cadmium may cause DNA damage, decrease DNA repair capacity, and increase genomic instability.

Material/Methods

The present study investigated the effects of BOK on the toxicity of cadmium chloride (CdCl₂) to human bronchial epithelial (16HBE) cells. We constructed BOK over-expressing (16HBE-BOK) cells and BOK knockdown (16HBE-shBOK) cells using the BOK-ORF plasmid and BOK-siRNA. qRT-PCR for BOK mRNA expression. We used Trypan blue exclusion assay for cell growth, MTT colorimetric assays for cells inhibition rate, and Comet assays for detecting damaged DNA.

Results

CdCl₂, at various concentrations and exposure times, increased BOK mRNA. 16HBE-BOK cells (BOK over-expressing) proliferated more than 16HBE cells after 72 h; 16HBE-shBOK (BOK knockdown) cells proliferated less. In addition, BOK deficiency enhanced cell death induced by CdCl₂. Similarly, CdCl₂- and H₂O₂-induced DNA damage was greater in BOK-deficient cells.

Conclusions

These findings support a role for BOK in CdCl₂-induced DNA damage and cell death.

Deciphering the Role of Protein Kinase D1 (PKD1) in Cellular Proliferation

Protein kinase D1 (PKD1) is a serine/threonine kinase that belongs to the calcium/calmodulin-dependent kinase family, and is involved in multiple mechanisms implicated in tumor progression such as cell motility, invasion, proliferation, protein transport, and apoptosis. While it is expressed in most tissues in the normal state, PKD1 expression may increase or decrease during tumorigenesis, and its role in proliferation is context-dependent and poorly understood. In this review, we present and discuss the current landscape of studies investigating the role of PKD1 in the proliferation of both cancerous and normal cells. Indeed, as a potential therapeutic target, deciphering whether PKD1 exerts a pro- or antiproliferative effect, and under what conditions, is of paramount importance.

Cadmium exposure alters steroid receptors and proinflammatory cytokine levels in endothelial cells in vitro: a potential mechanism of endocrine disruptor atherogenic effect

BACKGROUND

Cadmium (Cd) is a widespread environmental pollutant that causes alterations in human health acting as endocrine disruptor. Recent data suggest that cardiovascular system might be a contamination target tissue, since Cd is found in atheromatic plaques. Thus, the purpose of this study was to evaluate the consequence of Cd exposure of endothelial cells in vitro to evaluate detrimental effect in vascular system by a potential sex-steroid hormone receptor-dependent mechanism(s).

METHODS

To this aim, Human Umbilical Vein Endothelial Cells (HUVECs) were cultured and exposed to several concentrations of cadmium chloride (CdCl₂) for different interval times.

RESULTS

CdCl₂ exposure of HUVECs induced a significant increase of ERβ and Cyp19a1 at both mRNA and protein levels, while a drastic dose-dependent decrease of AR expression level was observed after 24 h of exposure. On the contrary, an increase of PhAR^ser308 as well as a reduction of PhGSK-3β^ser9 and PhAKT^ser473 was detected after 1 h treatment. This effect was consistently reduced by GSK inhibition. Furthermore, CdCl₂ abolished DHT-induced cell proliferation in HUVECs suggesting an antagonist-like effect of Cd on AR-mediated signaling. Remarkable, after 6 h CdCl₂-treatment, a relevant increase in TNF-α, IL-6 and IL-8 mRNA was observed and this effect was blocked by the presence of an ERβ-selective antagonist. Moreover, Cd-induced TxR1 overexpression, likely, correlated with the activation of p38 MAPK/NF-κB pathway.

CONCLUSION

In conclusion, our study demonstrates for the first time that Cd alters sex-steroid hormone receptors level and activity likely affecting intracellular signaling linked to a proinflammatory state in endothelial cells. This alteration might possibly lead to endothelial cell injury and vascular dysfunction and could be a mechanism of gender-specific atherogenic damages induced by endocrine disruptors and, thus, induce atherogenic events with increased risk of cardiovascular diseases in individuals exposed to this endocrine disruptor.

Green olive leaf extract (OLE) provides cytoprotection in renal cells exposed to low doses of cadmium

Cadmium (Cd) is a heavy and highly toxic metal that contaminates air, food and water. Cadmium accumulates in several organs altering normal functions. The kidney is the major organ at risk of damage from chronic exposure to cadmium as a contaminant in food and water. This study aims to investigate the beneficial effects of OLE in renal collecting duct MCD4 cells exposed to a low dose cadmium (1 μM). In MCD4 cells cadmium caused an increase in ROS production, as well as generation of lipid droplets and reduced cell viability. Moreover, cadmium exposure led to a remarkable increase in the frequency of micronuclei and DNA double-strand breaks, assessed using the alkaline comet assay. In addition, cadmium dramatically altered cell cytoskeleton architecture and caused S-glutathionylation of actin. Notably, all cadmium-induced cellular deregulations were prevented by co-treatment with OLE, possibly due to its antioxidant action and to the presence of bioactive phytocompounds. Indeed, OLE treatment attenuated Cd-induced actin S-glutathionylation, thereby stabilizing actin filaments. Taken together, these observations provide a novel insight into the biological action of OLE in renal cells and support the notion that OLE may serve as a potential adjuvant against cadmium-induced nephrotoxicity.

Protective effect of tetrahydrobiopterin on hepatic and renal damage after acute cadmium exposure in male rats

Cadmium (Cd) has been recognized as one of the most important environmental and industrial pollutants. This study investigated the impact of acute exposure to Cd on oxidative stress and the inflammatory marker interleukin-6 (IL-6) in the plasma of rats and the histological picture of liver and kidney, as well as to examine the potential protective effect of tetrahydrobiopterin (BH4).

METHODS

Rats were divided into control group, Cd group that received a single intraperitoneal (i.p.) dose of 4 mg/kg b.w. of CdCl2 and BH4+ Cd group that received a single dose of BH4 (20 mg/kg, i.p.) and subsequently exposed to a single dose of Cd 24 h after the BH4 treatment.

RESULTS

Cd increased the plasma levels of hepatic enzymes (ALT and AST), urea, creatinine, malondialdehyde (MDA), and IL-6 and decreased the superoxide dismutase (SOD) activity. Also, it induced histopathological alterations in the liver with severe degeneration, especially in centrilobular zones. Renal tubular epithelium showed vacuolated cytoplasm and dense nuclei. VEGF expression was mild. Ultrastuctural changes were seen in some renal tubules. The nuclei appeared distorted with electron dense chromatin. Mitochondria with destructed cristae were observed. BH4 pretreatment had protective effects, since it significantly reduced the levels of IL-6 and ameliorated the alteration in oxidative status biomarkers induced by Cd. Improvement of histopathological alterations was observed in Cd-groups. The nuclei were vesicular euchromatic, intact mitochondria and normal appearance of the filtration membrane. Moderate expression of VEGF was noted.

CONCLUSION

This study has provided clear evidence for the protective efficacy of BH4 against experimental Cd toxicity.

Dihydroartemisinin enhances VEGFR1 expression through up-regulation of ETS-1 transcription factor

Angiogenesis is required for tumor growth. Dihydroartemisinin (DHA), a the effective anti-malarial derivative of artemisinin, demonstrated potent anti-angiogenic activities that closely related to the regulation of vascular endothelial growth factor (VEGF) signaling cascade. VEGF receptor 1 (VEGFR1), a receptor in endothelial cells (ECs), coordinately regulate angiogenic activity triggered by ligand-receptor binding. Here we aimed to explore the effects of DHA on VEGFR1 expression in ECs. We found that DHA significantly increases VEGFR1 expression in human umbilical vein endothelial cells (HUVECs). In addition, DHA significantly upregulates the level of V-Ets Avian Erythroblastosis Virus E26 Oncogene Homolog 1 (ETS-1), a transcriptional factor which binds to the human VEGFR1 promoter. ChIP assay showed that DHA increases ETS-1 binding to the -52 ETS motif on the VEGFR1 promoter. Knockdown of ETS-1 by RNA interference abolished DHA-induced increase of VEGFR1 expression. Taken together, we demonstrated that DHA elevates VEGFR1 expression via up-regulation of ETS-1 transcription in HUVECs.

Low dose cadmium upregulates the expression of von Willebrand factor in endothelial cells

Cadmium (Cd) is a persistent and widespread environmental pollutant of continuing worldwide concern. Previous studies have suggested that Cd exposure increases the risk of cardiovascular diseases, such as atherosclerosis and hypertension. However, the underlying mechanisms are poorly understood. In this study, we observed that low dose Cd treatment induced von Willebrand factor (vWF) expression in vascular endothelial cells in mouse lung and kidney tissues. In vitro analysis showed that 1 μM Cd specifically upregulated vWF mRNA and protein expression in human umbilical vein endothelial cells (HUVECs), indicating that Cd targets vascular endothelial cells even at relatively low concentrations. Further study demonstrated that nuclear factor kappa B (NF-κB) and GATA3, two established transcription regulators of the vWF gene, were not altered in the presence of Cd. However, ETS-related gene (ERG) was significantly induced by 1 μM Cd. When ERG was knocked down by siRNA, Cd induced upregulation of vWF was totally blocked. Chromatin immunoprecipitation (ChIP) assay showed that Cd increases the binding of ERG on the -56 ETS motif on the human vWF promoter. These results indicated that ERG mediated the increased expression of vWF by Cd. Since vWF is a key regulator for vascular homeostasis, our findings may provide a novel mechanism for understanding low dose Cd induced development of vascular diseases.