Deferoxamine enhances cell migration and invasion through promotion of HIF-1α expression and epithelial-mesenchymal transition in colorectal cancer

Targeting mineral metabolism in cancer: Insights into signaling pathways and therapeutic strategies

Cancer remains the second leading cause of death worldwide, emphasizing the critical need for effective treatment and control strategies. Essential minerals such as copper, iron, zinc, selenium, phosphorous, calcium, and magnesium are integral to various biological processes and significantly influence cancer progression through altered metabolic pathways. For example, dysregulated copper levels promote tumor growth, while cancer cells exhibit an increased dependency on iron for signaling and redox reactions. Zinc influences tumor development through pathways such as Akt-p21. Selenium, primarily through its role in selenoproteins, exhibits anticancer potential but may also contribute to tumor progression. Similarly, dietary phosphate exacerbates tumorigenesis, metastasis, and angiogenesis through signaling pathway activation. Calcium, the most abundant mineral in the body, is tightly regulated within cells, and its dysregulation is a hallmark of various cancers. Magnesium deficiency, on the other hand, promotes cancer progression by fostering inflammation and free radical-induced DNA mutations. Interestingly, magnesium also plays a dual role, with low levels enhancing epithelial-mesenchymal transition (EMT), a critical process in cancer metastasis. This complex interplay of essential minerals underscores their potential as therapeutic targets. Dysregulation of these minerals and their pathways could be exploited to selectively target cancer cells, offering novel therapeutic strategies. This review summarizes current research on the abnormal accumulation or depletion of these microelements in tumor biology, drawing evidence from animal models, cell lines, and clinical samples. We also highlight the potential of these minerals as biomarkers for cancer diagnosis and prognosis, as well as therapeutic approaches involving metal chelators, pharmacological agents, and nanotechnology. By highlighting the intricate roles of these minerals in cancer biology, we aim to inspire further research in this critical yet underexplored area of oncology.

Long-term exposure to ambient fine particulate matter and periodontitis: An observational study using nationally representative survey data

AIM

The rising prevalence of periodontitis imposes substantial burdens on individuals and society. Identifying environmental risk factors for periodontitis may contribute to tackling the global public health burden of it. This study aimed to assess the association between long-term exposure to PM2.5 and periodontitis in a nationally representative population from China.

MATERIALS AND METHODS

In this multi-centre cross-sectional study of 372 communities in 31 provinces of Mainland China, we used data from the Fourth National Oral Health Survey of China in 2015-2016, in combination with high-resolution gridded concentrations of fine particulate matter (PM2.5). Logistic regression was applied to assess the relationship between long-term PM2.5 exposure and the risk of periodontitis. In addition, we examined whether the association varied by individual characteristics, and estimated the exposure-response relationship and the risk of damaged tooth in each tooth quadrant.

RESULTS

A total of 8391 participants from 96 cities were diagnosed with periodontitis, accounting for 60.04% (8391/13,459) of the participants. For each 10 μg/m3 increment in 1-, 3- and 5-year average concentrations of PM2.5, the risk of total periodontitis increased by 9.0% (95% confidence interval: 6.0%, 12.0%), 8.0% (6.0, 11·0) and 7.0% (5.0, 10.0), respectively. Mild periodontitis was more strongly associated with PM2.5 exposure than moderate and severe periodontitis. The teeth in the lower anterior, lower posterior or upper anterior are more susceptible to the effect of PM2.5 on the periodontal pocket, calculus and bleeding gums.

CONCLUSIONS

Long-term exposure to PM2.5 is significantly associated with an increased risk of periodontitis in the nationally representative Chinese population. Considering the rising prevalence of periodontitis, considerable costs of treatment, and substantially adverse effects on individuals and society, these findings suggest that stricter air quality regulations may help ease the burden of periodontal disease.

Thalassemia and malignancies: Updates from the literature

Thalassemia management has undergone significant development with the advancement in iron chelation therapy, which has led to a prolonged life expectancy. This has been accompanied by the emergence of several new morbidities and chronic diseases, including cancer. Over the years, multiple cases of solid and hematologic malignancies in thalassemia patients have been reported in the literature, with no clear mechanism for the development of cancer in these patients despite a number of potential mechanisms. However, the results of many studies have been contradictory regarding the risk of development of malignancies in thalassemia. The present review aims to discuss the available data on cancer and thalassemia in the literature, with the latest updates regarding possible malignancy development mechanisms, risks, and the most commonly reported types.

Diabetes and two kinds of primary tumors in a patient with thalassemia: a case report and literature review

Background

Thalassemia is a group of common genetic hematologic disorders characterized by deficient synthesis of the hemoglobin chain. Due to effective blood transfusion and optimization of chelate therapy, the survival of thalassemia patients and their overall quality of life have improved noticeably in the past few decades. As a consequence, the longer life expectancy has led to the manifestation of several concomitant morbidities, including heart disease, infections, cirrhosis, endocrine abnormalities, various malignancies, and so on. In this context, the probability and updated literature about some malignancy cases in patients with thalassemia build new scenarios for the next few years. We describe the first report of a thalassemic patient developing diabetes and head and neck cancer and try to summarize the possible predisposing factors and mechanisms behind their phenomenon.

Case presentation

The current case report describes a 50-year-old Asian man who has been diagnosed with thalassemia since childhood. In early 2017, he was also diagnosed with diabetes and started on insulin-hypoglycemic treatment. The patient was then diagnosed with primary non-keratinizing undifferentiated carcinoma of the nasopharynx in late February 2013. A biopsy of the left tongue revealed squamous cell carcinoma (SCC) in late March 2019.

Conclusions

We report the first case of a thalassemic patient developing diabetes and squamous cell carcinoma of the head and neck and discuss the possibility of a link between the three diseases. This specific case should alert physicians to the possibility of endocrinopathy and malignancy in thalassemic patients.

Ion modulatory treatments toward functional self-assembled neocartilage

Signals that recapitulate in vitro the conditions found in vivo, such as hypoxia or mechanical forces, contribute to the generation of tissue-engineered hyaline-like tissues. The cell regulatory processes behind hypoxic and mechanical stimuli rely on ion concentration; iron is required to degrade the hypoxia inducible factor 1a (HIF1α) under normoxia, whereas the initiation of mechanotransduction requires the cytoplasmic increase of calcium concentration. In this work, we propose that ion modulation can be used to improve the biomechanical properties of self-assembled neocartilage constructs derived from rejuvenated expanded minipig rib chondrocytes. The objectives of this work were 1) to determine the effects of iron sequestration on self-assembled neocartilage constructs using two doses of the iron chelator deferoxamine (DFO), and 2) to evaluate the performance of the combined treatment of DFO and ionomycin, a calcium ionophore that triggers cytoplasmic calcium accumulation. This study employed a two-phase approach. In Phase I, constructs treated with a high dose of DFO (100 µM) exhibited an 87% increase in pyridinoline crosslinks, a 57% increase in the Young's modulus, and a 112% increase in the ultimate tensile strength (UTS) of the neotissue. In Phase II, the combined use of both ion modulators resulted in 150% and 176% significant increases in the Young's modulus and UTS of neocartilage constructs, respectively; for the first time, neocartilage constructs achieved a Young's modulus of 11.76±3.29 MPa and UTS of 4.20±1.24 MPa. The results of this work provide evidence that ion modulation can be employed to improve the biomechanical properties in engineered neotissues. STATEMENT OF SIGNIFICANCE: The translation of tissue-engineered products requires the development of strategies capable of producing biomimetic neotissues in a replicable, controllable, and cost-effective manner. Among other functions, Fe2+ and Ca2+ are involved in the control of the hypoxic response and mechanotransduction, respectively. Both stimuli, hypoxia and mechanical forces, are known to favor chondrogenesis. This study utilized ion modulators to improve the mechanical properties self-assembled neocartilage constructs derived from expanded and rejuvenated costal chondrocytes via Fe2+ sequestration and Ca2+ influx, alone or in combination. The results indicate that ion modulation induced tissue maturation and a significant improvement of the mechanical properties, and holds potential as a tool to mitigate the need for bioreactors and engineer hyaline-like tissues.

Cigarette Smoke Particle-Induced Lung Injury and Iron Homeostasis

It is proposed that the mechanistic basis for non-neoplastic lung injury with cigarette smoking is a disruption of iron homeostasis in cells after exposure to cigarette smoke particle (CSP). Following the complexation and sequestration of intracellular iron by CSP, the host response (eg, inflammation, mucus production, and fibrosis) attempts to reverse a functional metal deficiency. Clinical manifestations of this response can present as respiratory bronchiolitis, desquamative interstitial pneumonitis, pulmonary Langerhans’ cell histiocytosis, asthma, pulmonary hypertension, chronic bronchitis, and pulmonary fibrosis. If the response is unsuccessful, the functional deficiency of iron progresses to irreversible cell death evident in emphysema and bronchiectasis. The subsequent clinical and pathological presentation is a continuum of lung injuries, which overlap and coexist with one another. Designating these non-neoplastic lung injuries after smoking as distinct disease processes fails to recognize shared relationships to each other and ultimately to CSP, as well as the common mechanistic pathway (ie, disruption of iron homeostasis).

Iron: An Essential Element of Cancer Metabolism

Cancer cells undergo considerable metabolic changes to foster uncontrolled proliferation in a hostile environment characterized by nutrient deprivation, poor vascularization and immune infiltration. While metabolic reprogramming has been recognized as a hallmark of cancer, the role of micronutrients in shaping these adaptations remains scarcely investigated. In particular, the broad electron-transferring abilities of iron make it a versatile cofactor that is involved in a myriad of biochemical reactions vital to cellular homeostasis, including cell respiration and DNA replication. In cancer patients, systemic iron metabolism is commonly altered. Moreover, cancer cells deploy diverse mechanisms to increase iron bioavailability to fuel tumor growth. Although iron itself can readily participate in redox reactions enabling vital processes, its reactivity also gives rise to reactive oxygen species (ROS). Hence, cancer cells further rely on antioxidant mechanisms to withstand such stress. The present review provides an overview of the common alterations of iron metabolism occurring in cancer and the mechanisms through which iron promotes tumor growth.

Ozone Reacts With Carbon Black to Produce a Fulvic Acid-Like Substance and Increase an Inflammatory Effect

Exposure to ambient ozone has been associated with increased human mortality. Ozone exposure can introduce oxygen-containing functional groups in particulate matter (PM) effecting a greater capacity of the particle for metal complexation and inflammatory effect. We tested the postulate that (1) a fulvic acid-like substance can be produced through a reaction of a carbonaceous particle with high concentrations of ozone and (2) such a fulvic acid-like substance included in the PM can initiate inflammatory effects following exposure of respiratory epithelial (BEAS-2B) cells and an animal model (male Wistar Kyoto rats). Carbon black (CB) was exposed for 72 hours to either filtered air (CB-Air) or approximately 100 ppm ozone (CB-O₃). Carbon black exposure to high levels of ozone produced water-soluble, fluorescent organic material. Iron import by BEAS-2B cells at 4 and 24 hours was not induced by incubations with CB-Air but was increased following coexposures of CB-O₃ with ferric ammonium citrate. In contrast to CB-Air, exposure of BEAS-2B cells and rats to CB-O₃ for 24 hours increased expression of pro-inflammatory cytokines and lung injury, respectively. It is concluded that inflammatory effects of carbonaceous particles on cells can potentially result from (1) an inclusion of a fulvic acid-like substance after reaction with ozone and (2) changes in iron homeostasis following such exposure.

Iron chelators in cancer therapy

Iron chelators have long been a target of interest as anticancer agents. Iron is an important cellular resource involved in cell replication, metabolism and growth. Iron metabolism is modulated in cancer cells reflecting their increased replicative demands. Originally, iron chelators were first developed for use in iron overload disorders, however, their potential as anticancer agents has been gaining increasing interest. This is due, in part, to the downstream effects of iron depletion such as the inhibition of proliferation through ribonucleotide reductase activity. Additionally, some chelators form redox active metal complexes with iron resulting in the production of reactive oxygen species and oxidative stress. Newer synthetic iron chelators such as Deferasirox, Triapine and di-2-pyridylketone-4,4,-dimethyl-3-thiosemicrbazone (Dp44mt) have improved pharmacokinetic properties over the older chelator Deferoxamine. This review examines and discusses the various iron chelators that have been trialled for cancer therapy including both preclinical and clinical studies. The successes and shortcomings of each of the chelators and their use in combination therapies are highlighted and future potential in the cancer therapy world is considered.

Altered Iron Metabolism and Impact in Cancer Biology, Metastasis, and Immunology

Iron is an essential nutrient that plays a complex role in cancer biology. Iron metabolism must be tightly controlled within cells. Whilst fundamental to many cellular processes and required for cell survival, excess labile iron is toxic to cells. Increased iron metabolism is associated with malignant transformation, cancer progression, drug resistance and immune evasion. Depleting intracellular iron stores, either with the use of iron chelating agents or mimicking endogenous regulation mechanisms, such as microRNAs, present attractive therapeutic opportunities, some of which are currently under clinical investigation. Alternatively, iron overload can result in a form of regulated cell death, ferroptosis, which can be activated in cancer cells presenting an alternative anti-cancer strategy. This review focuses on alterations in iron metabolism that enable cancer cells to meet metabolic demands required during different stages of tumorigenesis in relation to metastasis and immune response. The strength of current evidence is considered, gaps in knowledge are highlighted and controversies relating to the role of iron and therapeutic targeting potential are discussed. The key question we address within this review is whether iron modulation represents a useful approach for treating metastatic disease and whether it could be employed in combination with existing targeted drugs and immune-based therapies to enhance their efficacy.

Deferoxamine Enhanced Mitochondrial Iron Accumulation and Promoted Cell Migration in Triple-Negative MDA-MB-231 Breast Cancer Cells Via a ROS-Dependent Mechanism

In our previous study, Deferoxamine (DFO) increased the iron concentration by upregulating the expression levels of TfR1 and DMT1 and exacerbated the migration of triple-negative breast cancer cells. However, the mechanisms of iron distribution and utilization in triple-negative breast cancer cells with a DFO-induced iron deficiency are still unclear. In this study, triple-negative MDA-MB-231 and estrogen receptor (ER)-positive MCF-7 breast cancer cells were used to investigate the mechanisms of iron distribution and utilization with a DFO-induced iron deficiency. We found that the mitochondrial iron concentration was elevated in MDA-MB-231 cells, while it was decreased in MCF-7 cells after DFO treatment. The cellular and mitochondrial reactive oxygen species (ROS) levels increased in both breast cancer cell types under DFO-induced iron-deficient conditions. However, the increased ROS levels had different effects on the different breast cancer cell types: Cell viability was inhibited and apoptosis was enhanced in MCF-7 cells, but cell viability was maintained and cell migration was promoted in MDA-MB-231 cells through the ROS/NF-κB and ROS/TGF-β signaling pathways. Collectively, this study suggests that under DFO-induced iron-deficient conditions, the increased mitochondrial iron levels in triple-negative MDA-MB-231 breast cancer cells would generate large amounts of ROS to activate the NF-κB and TGF-β signaling pathways to promote cell migration.

The toxicology of air pollution predicts its epidemiology

The epidemiologic investigation has successively delineated associations of air pollution exposure with non-malignant and malignant lung disease, cardiovascular disease, cerebrovascular disease, pregnancy outcomes, perinatal effects and other extra-pulmonary disease including diabetes. Defining these relationships between air pollution exposure and human health closely parallels results of an earlier epidemiologic investigation into cigarette smoking and environmental tobacco smoke (ETS), two other particle-related exposures. Humic-like substances (HULIS) have been identified as a chemical component common to cigarette smoke and air pollution particles. Toxicology studies provide evidence that a disruption of iron homeostasis with sequestration of host metal by HULIS is a fundamental mechanistic pathway through which biological effects are initiated by cigarette smoke and air pollution particles. As a result of a common chemical component and a shared mechanistic pathway, it should be possible to extrapolate from the epidemiology of cigarette smoking and ETS to predict associations of air pollution exposure with human disease, which are currently unrecognized. Accordingly, it is anticipated that the forthcoming epidemiologic investigation will demonstrate relationships of air pollution with COPD causation, peripheral vascular disease, hypertension, renal disease, digestive disease, loss of bone mass/risk of fractures, dental disease, eye disease, fertility problems, and extrapulmonary malignancies.

Bio-inspired melanin nanoparticles induce cancer cell death by iron adsorption

Dysregulation of iron metabolism is a common characteristic of cancer cells. The rapid proliferation of the tumour cells means that there is an increased dependence upon iron compared to healthy cells. Chelation of iron can be undertaken with a number of different compounds, however, simply lowering systemic iron levels to control tumour growth is not possible since iron is essential for cellular metabolism in the rest of the body. Nanoparticulate iron chelators could overcome this difficulty by targeting to the tumour either by the passive enhanced permeation and retention effect, or by targeting ligands on the surface. Nanoparticles were prepared from melanin, which is a naturally occurring pigment that is widely distributed within the body, but that can chelate iron. The prepared nanoparticles were shown to be ~220 nm, and could adsorb 16.45 mmoles iron/g melanin. The nanoparticles showed no affect on control fibroblast cells at a concentration of 200 μM, whereas the immortalised cancer cell lines showed at least 56% reduction in cell growth. At a concentration of 1 mM melanin nanoparticles the cell growth could be reduced by 99% compared to the control. The nanoparticles also show no significant haemotoxicity, even at concentration of 500 μM. Melanin nanoparticles are therefore a viable prospect for destroying cancer cells via iron starvation.

PAR1 signaling on tumor cells limits tumor growth by maintaining a mesenchymal phenotype in pancreatic cancer

Protease activated receptor-1 (PAR1) expression is associated with disease progression and overall survival in a variety of cancers. However, the importance of tumor cell PAR1 in pancreatic ductal adenocarcinomas (PDAC) remains unexplored. Utilizing orthotopic models with wild type and PAR1-targeted PDAC cells, we show that tumor cell PAR1 negatively affects PDAC growth, yet promotes metastasis. Mechanistically, we show that tumor cell-specific PAR1 expression correlates with mesenchymal signatures in PDAC and that PAR1 is linked to the maintenance of a partial mesenchymal cell state. Indeed, loss of PAR1 expression results in well-differentiated pancreatic tumors in vivo, with enhanced epithelial characteristics both in vitro and in vivo. Taken together, we have identified a novel growth inhibitory role of PAR1 in PDAC, which is linked to the induction, and maintenance of a mesenchymal-like phenotype. The recognition that PAR1 actively limits pancreatic cancer cell growth suggest that the contributions of PAR1 to tumor growth differ between cancers of epithelial origin and that its targeting should be applied with care.

Iron chelation inhibits cancer cell growth and modulates global histone methylation status in colorectal cancer

Colorectal cancer (CRC) is one of the most common malignancies worldwide, and new treatment strategies for CRC are required because of the existing chemotherapy resistance. Iron chelators, which have been used widely for the treatment of iron-overload disease, were reported to exert anti-proliferative effects in cancer. However, the role of iron chelation in CRC was largely unknown. In this study, we found that the iron chelator DFO inhibited CRC cell growth significantly. In addition, the gene expression profile was greatly changed by DFO treatment, and many cell growth-related genes were dysregulated. Further study showed that DFO induced a significant increase in global histone methylation in CRC cells. However, the levels of histone methyltransferases and histone demethylases did not change in response to DFO treatment, implying that the enzymatic activity of these enzymes might be regulated by iron chelation. In conclusion, this study reveals a novel role for DFO in CRC cell growth, and is the first to demonstrate that global histone methylation is modulated by iron chelation in CRC cells.

The role of HIF-1α in the TGF-β2-mediated epithelial-to-mesenchymal transition of human lens epithelial cells

Human lens epithelial cells (HLE) undergo mesenchymal transition and become fibrotic during posterior capsule opacification (PCO), which is a frequent complication after cataract surgery. TGF-β2 has been implicated in this fibrosis. Previous studies have focused on the role of hypoxia-inducible factor-1α (HIF-1α) in fibrotic diseases, but the role of HIF-1α in the TGF-β2-mediated fibrosis in HLE is not known. TGF-β2 treatment (10 ng/mL, 48 h) increased the HIF-1α levels along with the EMT markers in cultured human lens epithelial cells (FHL124 cells). The increase in HIF-1α corresponded to an increase in VEGF-A in the culture medium. However, exogenous addition of VEGF-A (up to 10 ng/mL) did not alter the EMT marker levels in HLE. Addition of a prolyl hydroxylase inhibitor, dimethyloxalylglycine (DMOG, up to 10 µM), enhanced the levels of HIF-1α, and secreted VEGF-A but did not alter the EMT marker levels. However, treatment of cells with a HIF-1α translational inhibitor, KC7F2, significantly reduced the TGF-β2-mediated EMT response. This was accompanied by a reduction in the ERK phosphorylation and nuclear translocation of Snail and Slug. Together, these data suggest that HIF-1α is important for the TGF-β2-mediated EMT of human lens epithelial cells.

Human lung injury following exposure to humic substances and humic-like substances

Among the myriad particles the human respiratory tract is exposed to, a significant number are distinctive in that they include humic substances (HS) and humic-like substances (HULIS) as organic components. HS are heterogeneous, amorphous, organic materials which are ubiquitous occurring in all terrestrial and aqueous environments. HULIS are a complex class of organic, macromolecular compounds initially extracted from atmospheric aerosol particles which share some features with HS including an aromatic, polyacidic nature. As a result of having a variety of oxygen-containing functional groups, both HS and HULIS complex metal cations, especially iron. Following particle uptake by cells resident in the lung, host iron will be sequestered by HS- and HULIS-containing particles initiating pathways of inflammation and subsequent fibrosis. It is proposed that (1) human exposures to HS and HULIS of respirable size (<10 µm diameter) are associated with inflammatory and fibrotic lung disease and (2) following retention of particles which include HS and HULIS, the mechanism of cell and tissue injury involves complexation of host iron. Human inflammatory and fibrotic lung injuries following HS and HULIS exposures may include coal workers' pneumoconiosis, sarcoidosis, and idiopathic pulmonary fibrosis as well as diseases associated with cigarette smoking and exposures to emission and ambient air pollution particles.

Failure of ocular photodynamic therapy for secondary choroidal metastasis: a case report and literature review

The choroid is the most common site for intraocular metastatic disease. Photodynamic therapy (PDT) can effectively destroy malignant tissue and induce anti-tumor activity. Recent publications support its use as an effective therapy for the treatment of choroidal metastases, especially in the subfoveal region, resulting in subsequent vision preservation or improvement. Here, we introduce a case of choroidal metastasis, secondary to primary lung cancer. The progression of choroidal metastasis after PDT was followed up using spectral domain optical coherence tomography with point-to-point follow-up. Unfortunately, both the choroidal metastasis and serous retinal detachment increased after PDT. Since the mechanism underlying the therapeutic effect of PDT on choroidal metastasis is still not fully understood, deeper investigations into its safety, underlying molecular mechanisms, and treatment effects are critical for further PDT clinical usage in intraocular choroidal metastases.

Inhibitory effects of dieckol on hypoxia-induced epithelial-mesenchymal transition of HT29 human colorectal cancer cells

Hypoxia-induced epithelial-mesenchymal transition (EMT) has been identified as essential for tumor progression and metastasis. The present study examined the effects of an antioxidant, dieckol, on hypoxia-induced EMT in HT29 human colorectal cancer cells. HT29 cells were treated with a hypoxia-inducing agent, CoCl₂, and an increase in the levels of intracellular reactive oxygen species (ROS) and various morphological changes, such as loss of cell-cell contact and aggressive cell migration were observed. CoCl₂ also induced an increase in the expression of hypoxia-inducible factor 1α (HIF1α) and various mesenchymal-specific markers, including vimentin and snail family transcriptional repressor 1 (Snail1), and a decrease in the expression of E-cadherin, thus suggesting that CoCl₂ induced EMT in HT29 cells. Conversely, the CoCl₂-induced EMT of HT29 cells was suppressed following treatment with dieckol. In addition, ROS generation, EMT marker protein expression and intracellular localization, cell migration and cell invasion were attenuated following dieckol treatment. The findings of the present study suggested that dieckol may inhibit hypoxia-induced EMT in HT29 cells by regulating the levels of cellular ROS and protein expression levels downstream of the HIF1α signaling pathway. Therefore, dieckol has the potential to become an attractive therapeutic agent for the treatment of colorectal cancer.

Hypoxia enhances osteogenic differentiation in retinoic acid-treated murine-induced pluripotent stem cells

Hypoxic condition influences biological responses in various cell types. However, a hypoxic regulating osteogenic differentiation remains controversy. Here, an influence of short-term culture in hypoxic condition on osteogenic marker gene expression by retinoic acid-treated murine gingival fibroblast-derived induced pluripotent stem cells (RA-miPS) was investigated. Results demonstrated that hypoxic condition significantly upregulated Vegf, Runx2, Osx, and Ocn mRNA expression by RA-miPS in normal culture medium at day 3. Further, desferrioxamine significantly downregulated pluripotent marker (Nanog and Oct4) and enhanced osteogenic marker (Runx2, Osx, Dlx5, and Ocn) gene expression as well as promoted in vitro mineral deposition. However, the effect of cobalt chloride on osteogenic differentiation of RA-miPS was not robust. In summary, the results imply that hypoxic condition may be useful in the enhancement of osteogenic differentiation in RA-miPS.

Electronic Supplementary Material

Supplementary material is available for this article at 10.1007/s13770-016-9127-9 and is accessible for authorized users.

Propofol but not sevoflurane prevents mitochondrial dysfunction and oxidative stress by limiting HIF-1α activation in hepatic ischemia/reperfusion injury

Mitochondrial dysfunction, reactive oxygen species (ROS) production and oxidative stress during reperfusion are determinant in hepatic ischemia/reperfusion (I/R) injury but may be impacted by different anesthetic agents. Thus, we aimed at comparing the effects of inhaled sevoflurane or intravenous propofol anesthesia on liver mitochondria in a rodent model of hepatic I/R injury. To this, male Wistar rats underwent I/R surgery using sevoflurane or propofol. In the I/R model, propofol limited the raise in serum aminotransferase levels as compared to sevoflurane. Mitochondrial oxygen uptake, respiratory activity, membrane potential and proton leak were altered in I/R; however, this impairment was significantly prevented by propofol but not sevoflurane. In addition, differently from sevoflurane, propofol limited hepatic I/R-induced mitochondria H2O2 production rate, free radical leak and hydroxynonenal-protein adducts levels. The I/R group anesthetized with propofol also showed a better recovery of hepatic ATP homeostasis and conserved integrity of mitochondrial PTP. Moreover, hypoxia-inducible factor 1 alpha (HIF-1α) expression was limited in such group. By using a cell model of desferoxamine-dependent HIF activation, we demonstrated that propofol was able to inhibit apoptosis and mitochondrial depolarization associated to HIF-1α action. In conclusion, hepatic I/R injury induces mitochondrial dysfunction that is not prevented by inhaled sevoflurane. On the contrary, propofol reduces liver damage and mitochondrial dysfunction by preserving respiratory activity, membrane potential and energy homeostasis, and limiting free radicals production as well as PTP opening. These hepatoprotective effects may involve the inhibition of HIF-1α.

Targeting cancer by binding iron: Dissecting cellular signaling pathways

Newer and more potent therapies are urgently needed to effectively treat advanced cancers that have developed resistance and metastasized. One such strategy is to target cancer cell iron metabolism, which is altered compared to normal cells and may facilitate their rapid proliferation. This is supported by studies reporting the anti-neoplastic activities of the clinically available iron chelators, desferrioxamine and deferasirox. More recently, ligands of the di-2-pyridylketone thiosemicarbazone (DpT) class have demonstrated potent and selective anti-proliferative activity across multiple cancer-types in vivo, fueling studies aimed at dissecting their molecular mechanisms of action. In the past five years alone, significant advances have been made in understanding how chelators not only modulate cellular iron metabolism, but also multiple signaling pathways implicated in tumor progression and metastasis. Herein, we discuss recent research on the targeting of iron in cancer cells, with a focus on the novel and potent DpT ligands. Several key studies have revealed that iron chelation can target the AKT, ERK, JNK, p38, STAT3, TGF-β, Wnt and autophagic pathways to subsequently inhibit cellular proliferation, the epithelial-mesenchymal transition (EMT) and metastasis. These developments emphasize that these novel therapies could be utilized clinically to effectively target cancer.

Construction and Quantitative Validation of Chicken CXCR4 Expression Reporter

Site directional migration is an important biological event and an essential behavior for latent migratory cells. A migratory cell maintains its motility, survival, and proliferation abilities by a network of signaling pathways where CXCR4/SDF signaling route plays crucial role for directed homing of a polarized cell. The chicken embryo due to its specific vasculature modality has been used as a valuable model for organogenesis, migration, cancer, and metastasis. In this research, the regulatory regions of chicken CXCR4 gene have been characterized in a chicken hematopoietic lymphoblast cell line (MSB1). A region extending from -2000 bp upstream of CXCR4 gene to +68 after its transcriptional start site, in addition to two other mutant fragments were constructed and cloned in a promoter-less reporter vector. Promoter activity was analyzed by quantitative real-time RT-PCR and flow cytometry techniques. Our findings show that the full sequence from -2000 to +68 bp of CXCR4 regulatory region is required for maximum promoter functionality, while the mutant CXCR4 promoter fragments show a partial promoter activity. The chicken CXCR4 promoter validated in this study could be used for characterization of directed migratory cells in chicken development and disease models.

HIF-1α Promotes Epithelial-Mesenchymal Transition and Metastasis through Direct Regulation of ZEB1 in Colorectal Cancer

It is well recognized that hypoxia-inducible factor 1 alpha (HIF-1α) is involved in cancer metastasis, chemotherapy and poor prognosis. We previously found that deferoxamine, a hypoxia-mimetic agent, induces epithelial-mesenchymal transition (EMT) in colorectal cancer. Therefore, here we explored a new molecular mechanism for HIF-1α contributing to EMT and cancer metastasis through binding to ZEB1. In this study, we showed that overexpression of HIF-1α with adenovirus infection promoted EMT, cell invasion and migration in vitro and in vivo. On a molecular level, HIF-1α directly binding to the proximal promoter of ZEB1 via hypoxia response element (HRE) sites thus increasing the transactivity and expression of ZEB1. In addition, inhibition of ZEB1 was able to abrogate the HIF-1α-induced EMT and cell invasion. HIF-1α expression was highly correlated with the expression of ZEB1 in normal colorectal epithelium, primary and metastatic CRC tissues. Interestingly, both HIF-1α and ZEB1 were positively associated with Vimentin, an important mesenchymal marker of EMT, whereas negatively associated with E-cadherin expression. These findings suggest that HIF-1α enhances EMT and cancer metastasis by binding to ZEB1 promoter in CRC. HIF-1α and ZEB1 are both widely considered as tumor-initiating factors, but our results demonstrate that ZEB1 is a direct downstream of HIF-1α, suggesting a novel molecular mechanism for HIF-1α-inducing EMT and cancer metastasis.

Activation of platelet protease-activated receptor-1 induces epithelial-mesenchymal transition and chemotaxis of colon cancer cell line SW620

The aim of the present study was to examine the role of protease-activated receptor-1 (PAR1)-stimulated platelet activation in the epithelial-mesenchymal transition (EMT) and migration of colon cancer cells, and to identify the underlying mechanisms. TFLLR-NH₂, a PAR1 agonist, was used to activate platelets and the platelet supernatants were used to treat the SW620 colon cancer cell line. Expression of E-cadherin and vimentin on SW620 cells was detected by immunofluorescence and western blotting, and the level of the transforming growth factor β1 (TGF-β1) was measured using ELISA following the activation of platelets by TFLLR-NH₂. miR-200b expression was detected using quantitative PCR in SW620 cells. In order to investigate the chemotactic ability of the SW620 cells, the expression of CXC chemokine receptor type 4 (CXCR4) was measured by flow cytometry. Transwell migration assays were performed following exposure of the cells to the supernatant of PAR1-activated platelets. SW620 cells cultured in the supernatant of TFLLR-NH₂-activated platelets upregulated E-cadherin expression and downregulated the vimentin expression. In the in vitro platelet culture system, a TFLLR-NH₂ dose-dependent increase of secreted TGF-β1 was detected in the supernatant. The activation of PAR1 on the platelets led to the inhibition of miR-200b expression in the SW620 cells that were cultured in platelet-conditioned media. The number of SW620 cells that penetrated through the Transwell membrane increased with the dose of TFLLR-NH₂ used to treat the platelets. The percentage of CXCR4-positive SW620 cells was significantly higher when they were exposed to the supernatant of platelets cultured for 24 h with PAR1 agonist than when cultured in non-conditioned media (40.89±6.74 vs. 3.47±1.40%, P<0.01). Platelet activation with a PAR1 agonist triggered TGF-β secretion, which induced EMT of SW620 human colon cancer cells via the downregulation of miR-200b expression, and activated platelets had a chemotactic effect on colon cancer cells mediated by the upregulation of CXCR4 on the cell surface.