Ferritin stimulates breast cancer cells through an iron-independent mechanism and is localized within tumor-associated macrophages

Serum ferritin predicted prognosis in patients with nasopharyngeal carcinoma

Elevated serum ferritin (SF) levels have been associated with poor prognosis in various cancer types, but its impact on nasopharyngeal carcinoma (NPC) remains unclear. This retrospective study analyzed clinical data from 252 non-metastatic NPC patients admitted to Hainan General Hospital between January 2014 and May 2016. SF levels were measured using the chemiluminescence method. Patients were categorized into low, medium, and high-level SF groups based on tertile median SF levels. Survival outcomes were assessed using Kaplan-Meier analysis and Cox regression models. The overall survival rates of the entire patient cohort at 1, 3, 5, and 8 years were 95.2%, 85.7%, 76.2%, and 68.9% respectively. The high-level SF group (SF > 164.00 ng/mL) had significantly worse overall survival (83.1 vs 96.3 months, P = 0.023) and progression-free survival (77.8 vs 93.3 months, P = 0.019) compared to the low-level SF group. Univariate and multivariate analyses confirmed that high SF levels, along with T3/T4 staging and N3 staging, were independent risk factors for poor prognosis. In conclusion, high SF levels are associated with shorter overall survival and progression-free survival in NPC patients.

Cytochrome b561 regulates iron metabolism by activating the Akt/mTOR pathway to promote Breast Cancer Cells proliferation

Breast cancer (BC) is the leading cause of cancer-related mortality in women, necessitating the development of novel therapeutic targets. While cytochrome b561 (CYB561) expression is associated with poor prognosis in BC, the precise role of CYB561 in BC and its potential mechanisms remain unclear. In the present study, we found that CYB561 plays an essential role in BC growth. CYB561 expression was up-regulated in surgically resected cancerous tissues and in six BC cell lines. Lentivirus-mediated CYB561 knockdown in BC cells significantly reduced their proliferation, migration, and invasiveness. CYB561 participates in the regulation of iron metabolism in BC. CYB561 knockdown reduced total iron content, increased ferrous iron content, and down-regulated the expression of proteins associated with iron metabolism (transferrin receptor 1, divalent metal transporter 1, and ferritin heavy chain 1). Conversely, up-regulation of CYB561 through co-incubation with exogenous iron (ferric ammonium citrate) produced contrary outcomes. Additionally, CYB561 activated the protein kinase B/mammalian target of rapamycin (Akt/mTOR) signaling pathway in BC cells. Down-regulation of CYB561 expression inhibited the Akt/mTOR signaling pathway activity. The application of an mTOR agonist (MHY1485) rescued this negative effect, as well as the inhibitory effect of CYB561 knockdown on cell proliferation. Importantly, the dual mTOR inhibitor MLN0128 (50 nM, 48 h) down-regulated CYB561 expression and the iron metabolism-related proteins transferrin receptor, divalent metal transporter 1, and ferritin heavy chain 1, whereas the mTOR agonist MHY1485 rescued the down-regulation of CYB561 knockdown on iron metabolism-related proteins. We conclude that CYB561 promotes the proliferation of BC cells by regulating iron metabolism through the activation of the Akt/mTOR signaling pathway.

Overexpression of ferritin light chain as a poor prognostic factor for breast cancer

BACKGROUND

Ferritin light chain (FTL) is involved in tumor progression, but the specific molecular processes by which FTL affects the development of breast cancer (BRCA) have remained unknown. In this research, the clinicopathological significance of FTL overexpression in BRCA was investigated.

METHODS

To investigate the role of FTL in BRCA, we utilized multiple online databases to analyse FTL expression levels in BRCA. Next, we reviewed the expression and localization of the FTL protein in BRCA by immunohistochemistry (IHC), Western blot (WB) and immunofluorescence (IF) staining. To assess the impact of FTL on patient prognosis, we conducted Kaplan‒Meier, univariate and multivariate survival analyses. The relationship between FTL and immune infiltration in BRCA was also analysed in the TISCH and SangerBox databases. MTT, malondialdehyde (MDA) and reactive oxygen species (ROS) assays were carried out to investigate the molecular mechanisms of FTL action in BRCA cells.

RESULTS

FTL was significantly upregulated in BRCA compared to normal tissues. Its expression significantly linked to histological grade (P = 0.038), PR expression (P = 0.021), Her2 expression (P = 0.012) and Ki-67 expression (P = 0.040) in patients with BRCA. Furthermore, the expression of the FTL protein was higher in the BRCA cell lines than in the normal breast cells and mainly localized in the cytoplasm. Compared to patients with a low level of FTL expression, patients with a high level of FTL expression showed lower overall survival (OS). More convincingly, univariate and multivariate statistical analyses revealed that FTL expression (P = 0.000), ER expression (P = 0.036) and Her2 expression (P = 0.028) were meaningful independent prognostic factors in patients with BRCA. FTL was associated with immune infiltration in BRCA. Functional experiments further revealed that FTL knockdown inhibited the capacity of proliferation and increased the level of oxidative stress in BRCA cells.

CONCLUSIONS

Overexpression of FTL was associated with the progression of BRCA. FTL overexpression may become a biomarker for the evaluation of poor prognosis in patients with BRCA.

Tumor Abnormality-Oriented Nanomedicine Design

Anticancer nanomedicines have been proven effective in mitigating the side effects of chemotherapeutic drugs. However, challenges remain in augmenting their therapeutic efficacy. Nanomedicines responsive to the pathological abnormalities in the tumor microenvironment (TME) are expected to overcome the biological limitations of conventional nanomedicines, enhance the therapeutic efficacies, and further reduce the side effects. This Review aims to quantitate the various pathological abnormalities in the TME, which may serve as unique endogenous stimuli for the design of stimuli-responsive nanomedicines, and to provide a broad and objective perspective on the current understanding of stimuli-responsive nanomedicines for cancer treatment. We dissect the typical transport process and barriers of cancer drug delivery, highlight the key design principles of stimuli-responsive nanomedicines designed to tackle the series of barriers in the typical drug delivery process, and discuss the "all-into-one" and "one-for-all" strategies for integrating the needed properties for nanomedicines. Ultimately, we provide insight into the challenges and future perspectives toward the clinical translation of stimuli-responsive nanomedicines.

Ferroptosis, autophagy, tumor and immunity

Ferroptosis was first proposed in 2012, a new form of cell death. Autophagy plays a crucial role in cell clearance and maintaining homeostasis. Autophagy is involved in the initial step of ferroptosis under the action of histone elements such as NCOA4, RAB7A, and BECN1. Ferroptosis and autophagy are involved in tumor progression, treatment, and drug resistance in the tumor microenvironment. In this review, we described the mechanisms of ferroptosis, autophagy, and tumor and immunotherapy, respectively, and emphasized the relationship between autophagy-related ferroptosis and tumor.

Uptake of H-ferritin by Glioblastoma stem cells and its impact on their invasion capacity

PURPOSE

Iron acquisition is key to maintaining cell survival and function. Cancer cells in general are considered to have an insatiable iron need. Iron delivery via the transferrin/transferrin receptor pathway has been the canonical iron uptake mechanism. Recently, however, our laboratory and others have explored the ability of ferritin, particularly the H-subunit, to deliver iron to a variety of cell types. Here, we investigate whether Glioblastoma (GBM) initiating cells (GICs), a small population of stem-like cells, are known for their iron addiction and invasive nature acquire exogenous ferritin, as a source of iron. We further assess the functional impact of ferritin uptake on the invasion capacity of the GICs.

METHODS

To establish that H-ferritin can bind to human GBM, tissue-binding assays were performed on samples collected at the time of surgery. To interrogate the functional consequences of H-ferritin uptake, we utilized two patient-derived GIC lines. We further describe H-ferritin's impact on GIC invasion capacity using a 3D invasion assay.

RESULTS

H-ferritin bound to human GBM tissue at the amount of binding was influenced by sex. GIC lines showed uptake of H-ferritin protein via transferrin receptor. FTH1 uptake correlated with a significant decrease in the invasion capacity of the cells. H-ferritin uptake was associated with a significant decrease in the invasion-related protein Rap1A.

CONCLUSION

These findings indicate that extracellular H-ferritin participates in iron acquisition to GBMs and patient-derived GICs. The functional significance of the increased iron delivery by H-ferritin is a decreased invasion capacity of GICs potentially via reduction of Rap1A protein levels.

Iron Metabolism in Cancer and Senescence: A Cellular Perspective

Iron participates in a number of biological processes and plays a crucial role in cellular homeostasis. Alterations in iron metabolism are considered hallmarks of cancer and drivers of aggressive behaviors, such as uncontrolled proliferation, resistance to apoptosis, enhanced metastatic ability, increased cell plasticity and stemness. Furthermore, a dysregulated iron metabolism has been associated with the development of an adverse tumor microenvironment. Alterations in iron metabolism have been described in cellular senescence and in aging. For instance, iron has been shown to accumulate in aged tissues and in age-related diseases. Furthermore, in vitro studies demonstrate increases in iron content in both replicative and stress-induced senescent cells. However, the role, the mechanisms of regulation and dysregulation and the effects of iron metabolism on senescence remain significantly less characterized. In this review, we first provide an overview of iron metabolism and iron regulatory proteins. Then, we summarize alterations in iron homeostasis in cancer and senescence from a cellular point of view.

A novel view of ferritin in cancer

Since its discovery more than 85 years ago, ferritin has principally been known as an iron storage protein. However, new roles, beyond iron storage, are being uncovered. Novel processes involving ferritin such as ferritinophagy and ferroptosis and as a cellular iron delivery protein not only expand our thinking on the range of contributions of this protein but present an opportunity to target these pathways in cancers. The key question we focus on within this review is whether ferritin modulation represents a useful approach for treating cancers. We discussed novel functions and processes of this protein in cancers. We are not limiting this review to cell intrinsic modulation of ferritin in cancers, but also focus on its utility in the trojan horse approach in cancer therapeutics. The novel functions of ferritin as discussed herein realize the multiple roles of ferritin in cell biology that can be probed for therapeutic opportunities and further research.

Ferritin-Hijacking Nanoparticles Spatiotemporally Directing Endogenous Ferroptosis for Synergistic Anticancer Therapy

Existing ferroptosis as an iron-dependent form of regulated cell death primarily relies on importing exogenous iron. However, the excessive employment of toxic materials may cause potential adverse effects on human health. Herein, a ferritin-hijacking nanoparticle (Ce6-PEG-HKN₁₅ ) is fabricated, by conjugating the ferritin-homing peptide HKN₁₅ with the photosensitizer chlorin e6 (Ce6) for endogenous ferroptosis without introducing Fenton-reactive metals. Once internalized, the designed Ce6-PEG-HKN₁₅ NPs can specifically accumulate around ferritin. With laser irradiation, the activated Ce6 in nanoparticles potently generates reactive oxygen species (ROS) surrounding ferritin. Abundant ROS not only helps to destroy the iron storage protein and activate endogenous ferroptosis but also directly kill tumor cells. In turn, the released iron partially interacts with intracellular excess H₂ O₂ to produce O₂ , thereby enhancing photodynamic therapy and further amplifying oxidative stress. Overall, this work highlights the possibility of endogenous ferroptosis via spatiotemporally destroying ferritin, offering a paradigm for synergistic ferroptosis-photodynamic antitumor therapy.

M2 Macrophage-Derived Exosomal Ferritin Heavy Chain Promotes Colon Cancer Cell Proliferation

Colon cancer is a widespread life-threatening malignancy with complex and multifactorial etiology. Both epidemiological cohort studies and basic research support the substantial role of iron metabolism in colon cancer. Thus, understanding the mechanisms of how essential iron metabolic proteins are dysregulated may provide new treatment strategies for colon cancer. Ferritin is the main iron storage protein that occupies a vital position in iron metabolism. Studies reported that ferritin is differentially highly expressed in tissues from multiple malignancies. However, the source and function of highly expressed ferritin in colon cancer have not been explored. In this study, we found that the protein level but not RNA level of ferritin heavy chain (FTH1) was upregulated in colon cancer using paired clinical samples. Co-culture system was used to mimic the in vivo circumstance and study the cell-cell communication of macrophages and colon cancer cells. Results showed that M2 macrophages could substantially increase the FTH1 levels in colon cancer cells. This effect could be blocked by the exosome biogenesis/ secretion inhibitor GW4869, implying the vital role of exosomes in this biological process. Besides, we found that purified exosomes from M2 macrophages could deliver FTH1 into colon cancer cells and promote cell proliferation. Furtherly, EdU assay and live cell imaging system were performed in FTH1-OE (overexpression) colon cancer cell lines and confirmed the cell proliferation promoting effect of FTH1. Our results unveil the source and function of highly expressed FTH1 in colon cancer and provide a new potential therapeutic target for the treatment of colon cancer.

Iron metabolism, ferroptosis, and lncRNA in cancer: knowns and unknowns

Cancer cells undergo substantial metabolic alterations to sustain increased energy supply and uncontrolled proliferation. As an essential trace element, iron is vital for many biological processes. Evidence has revealed that cancer cells deploy various mechanisms to elevate the cellular iron concentration to accelerate proliferation. Ferroptosis, a form of cell death caused by iron-catalyzed excessive peroxidation of polyunsaturated fatty acids (PUFAs), is a promising therapeutic target for therapy-resistant cancers. Previous studies have reported that long noncoding RNA (lncRNA) is a group of critical regulators involved in modulating cell metabolism, proliferation, apoptosis, and ferroptosis. In this review, we summarize the associations among iron metabolism, ferroptosis, and ferroptosis-related lncRNA in tumorigenesis. This information will help deepen understanding of the role of lncRNA in iron metabolism and raise the possibility of targeting lncRNA and ferroptosis in cancer combination therapy.

Macrophage density is an adverse prognosticator for ipsilateral recurrence in ductal carcinoma in situ

INTRODUCTION

There is evidence that supports the association of dense tumor infiltrating lymphocyte (TILs) with an increased risk of ipsilateral recurrence in ductal carcinoma in situ (DCIS). However, the association of cellular composition of DCIS immune microenvironment with the histopathologic parameters and outcome is not well understood.

METHODS

We queried our institutional database for patients with pure DCIS diagnosed between 2010 and 2019. Immunohistochemical studies for CD8, CD4, CD68, CD163, and FOXP3 were performed and evaluated in the DCIS microenvironment using tissue microarrays. Statistical methods included Fisher's exact test for categorical variables and the two-sample t-test or the Wilcoxon Rank-Sum test for continuous variables.

RESULTS

The analytic sample included 67 patients. Median age was 62 years (range = 53 to 66) and median follow up was 6.7 years (range = 5.3 to 7.8). Thirteen patients had ipsilateral recurrence. Of all the clinicopathologic variables, only the DCIS size and TIL density were significantly associated with recurrence (p = 0.023 and 0.006, respectively). After adjusting for age and TIL density, only high CD68 (>50) and high CD68/CD163 ratio (>0.46) correlated with ipsilateral recurrence (p = 0.026 and 0.013, respectively) and shorter time to recurrence [hazard ratio 4.87 (95% CI: 1.24-19, p = 0.023) and 10.32 (95% CI: 1.34-80, p = 0.025), respectively].

CONCLUSIONS

In addition to DCIS size and TIL density, high CD68+ tumor-associated macrophages predict ipsilateral recurrence in DCIS. High CD68+ macrophage density and CD68/CD163 ratio also predict a shorter time to recurrence.

Ferritin - from iron, through inflammation and autoimmunity, to COVID-19

While it took decades to arrive to a conclusion that ferritin is more than an indicator of iron storage level, it took a short period of time through the COVID-19 pandemic to wonder what the reason behind high levels of ferritin in patients with severe COVID-19 might be. Unsurprisingly, acute phase reactant was not a satisfactory explanation. Moreover, the behavior of ferritin in patients with severe COVID-19 and the subsequent high mortality rates in patients with high ferritin levels necessitated further investigations to understand the role of ferritin in the diseases. Ferritin was initially described to accompany various acute infections, both viral and bacterial, indicating an acute response to inflammation. However, with the introduction of the hyperferritinemic syndrome connecting four severe pathological conditions such as adult-onset Still's disease, macrophage activation syndrome, catastrophic antiphospholipid syndrome, and septic shock added another aspect of ferritin where it could have a pathogenetic role rather than an extremely elevated protein only. In fact, suggesting that COVID-19 is a new member in the spectrum of hyperferritinemic syndrome besides the four mentioned conditions could hopefully direct further search on the pathogenetic role of ferritin. Doubtlessly, improving our understanding of those aspects of ferritin would enormously contribute to better coping with severe diseases in terms of treatment and prevention of complications. The origin, history, importance, and the advances of searching the role of ferritin in various pathological and clinical processes are presented hereby in our article. In addition, the implications of ferritin in COVID-19 are addressed.

Protein-Based Nanoparticles for the Imaging and Treatment of Solid Tumors: The Case of Ferritin Nanocages, a Narrative Review

Protein nanocages have been studied extensively, due to their unique architecture, exceptional biocompatibility and highly customization capabilities. In particular, ferritin nanocages (FNs) have been employed for the delivery of a vast array of molecules, ranging from chemotherapeutics to imaging agents, among others. One of the main favorable characteristics of FNs is their intrinsic targeting efficiency toward the Transferrin Receptor 1, which is overexpressed in many tumors. Furthermore, genetic manipulation can be employed to introduce novel variants that are able to improve the loading capacity, targeting capabilities and bio-availability of this versatile drug delivery system. In this review, we discuss the main characteristics of FN and the most recent applications of this promising nanotechnology in the field of oncology with a particular emphasis on the imaging and treatment of solid tumors.

The association between serum ferritin levels and malignant intraductal papillary mucinous neoplasms

BACKGROUND

Serum ferritin levels are elevated in many malignancies. In this study, we showed the performance of serum ferritin in identifying malignant intraductal papillary mucinous neoplasms (IPMNs).

METHODS

A total of 151 patients with pathologically confirmed IPMNs were enrolled. Serum tumor biomarker (carbohydrate antigen 19-9 (CA19-9) and carcinoembryonic antigen (CEA)) levels and serum ferritin levels were recorded. Lesion location, tumor size, diameter of the main pancreatic duct (MPD), mural nodule, and IPMN type, were collected from imaging examinations. IPMNs with high grade dysplasia and associated invasive carcinoma were considered malignant IPMNs.

RESULTS

Serum ferritin levels in patients with malignant IPMNs were higher than those in patients with nonmalignant IPMNs (p <  0.05). Serum ferritin was an independent factor for the occurrence of malignant IPMNs (odds ratio (OR) = 1.18, 95% confidence interval (CI):1.01-1.39). A similar trend was found between high serum ferritin (> 149 ng/ml) and malignant IPMNs (OR = 5.64, 95% CI:1.78-17.92). The area under the curve (AUC) of serum ferritin was higher than that of CEA and CA19-9 in identifying malignant IPMNs (AUC = 0.67 vs. AUC = 0.58, 0.65). The combination of serum ferritin with IPMN type showed a similar performance to MPD diameter and the combination of serum CA19-9 with IPMN types in identifying malignant IPMNs (AUC = 0.78 vs. AUC = 0.79, 0.77) and invasive carcinoma (AUC = 0.77 vs. AUC = 0.79, 0.79).

CONCLUSIONS

Elevated serum ferritin is a factor associated with malignant IPMNs. Serum ferritin may be a useful marker for identifying malignancy in IPMNs.

Prognostic Value of International Normalized Ratio-to-Albumin Ratio and Ferritin Level in Chronic Liver Patients with Hepatocellular Carcinoma

OBJECTIVE

Hepatocellular carcinoma (HCC) is the sixth among the most common cancers and the fourth among cancer-related causes of death in the world. In the evaluation of liver function in HCC patients, parameters such as albumin-bilirubin, prothrombin time-international normalized ratio (PT-INR) to albumin ratio (PTAR) are used among new methods other than Child-Pugh and MELD scores. Biomarkers are widely used in clinical practice in cases such as diagnosing various diseases, evaluating treatment response and predicting prognosis. We aimed to evaluate the prognostic role of serum ferritin and INR/albumin ratio in patients with chronic liver disease who develop HCC.

METHODS

This retrospective study included 534 patients who were followed up with the diagnosis of HCC between 2009 and 2020. The patients with HCC etiology were evaluated in 3 groups (chronic hepatitis B group, chronic hepatitis C group, and other group). When comparing serum ferritin level and prothromin time-international normalized ratio to albumin ratio with Child Pugh score (CTP) in chronic liver patients with HCC, liver functional reserve and its role in predicting prognosis were investigated.

RESULTS

The serum ferritin level was 226 ± 334 in the CTP A group, 239 ± 302 in the CTP B group, and 678 ± 966 in the CTP C group, and the p value was 0.001. The PTAR CTP group was 0.35 ± 0.10, the CTP B group was 0.50 ± 0.26, the CTP C group was 1.18 ± 6.01, and the p value was 0.001. Multivariant analysis results showed that ferritin hazard ratio is 1.00, 95% CI 0.99-1.00, and p value was 0.09, and PTAR hazard ratio is 1.38, 95% CI 2.37-8.00, and p value was 0.49. The etiological distribution of HCC was determined as HBV (61.6%), HCV (19.9%), and other etiologies (18.5%). Significant values were determined for age, gender, glucose, GGT, T. cholesterol, and tumor diameter parameters according to etiological distribution.

CONCLUSIONS

Serum ferritin level and PTAR score increased in proportion to the severity of liver disease and were associated with poor prognosis. We think that high serum ferritin and PTAR score is a prognostic biomarker in predicting the synthesis function of the liver and mortality in critically ill patients with cirrhosis.

Pre-Clinical Insights into the Iron and Breast Cancer Hypothesis

Population studies, systematic reviews, and meta-analyses have revealed no relationship between iron status and breast cancer, a weak positive association, or a small protective effect of low iron status. However, in those studies, the authors concluded that further investigation was merited. The set of experiments reported here used preclinical models to assess the likely value of further investigation. The effects of iron status on the initiation and promotion stage of mammary carcinogenesis are reported. Using the classical model of cancer initiation in the mammary gland, 7,12 dimethyl-benz[α]anthracene-induced carcinogenesis was unaffected by iron status. Similarly, excess iron intake showed no effect on the promotion stage of 1-methyl-1-nitrosurea-induced mammary carcinogenesis, though iron deficiency exerted a specific inhibitory effect on the carcinogenic process. Though iron-mediated cellular oxidation is frequently cited as a potential mechanism for effects on breast cancer, no evidence of increased oxidative damage to DNA attributable to excess iron intake was found. The reported preclinical data fail to provide convincing evidence that the further evaluation of the iron–breast cancer risk hypotheses is warranted and underscore the value of redefining the referent group in population-based studies of iron–cancer hypotheses in other tissues.

A case-control study in Taiwanese cohort and meta-analysis of serum ferritin in pancreatic cancer

Pancreatic cancer is one of the most lethal diseases which lack an early diagnostic marker. We investigated whether serum ferritin (SF) reflects risk for pancreatic cancer and potential genes that may contribute ferritin and pancreatic cancer risks. We performed a meta-analysis of relevant studies on SF and pancreatic cancer risk by searching articles in PUBMED and EMBASE published up to 1 March 2020. We also collected serum samples from Taipei Medical University Joint Biobank and compared SF levels in 34 healthy controls and 34 pancreatic cancer patients. An Oncomine database was applied as a platform to explore a series of genes that exhibited strong associations between ferritin and pancreatic cancer. Herein, we show that high levels of SF can indicate risk of pancreatic cancer, suggesting SF as the new tumor marker that may be used to help pancreatic cancer diagnosis. We also found that expressions of iron homeostasis genes (MYC, FXN) and ferroptosis genes (ALOX15, CBS, FDFT1, LPCAT3, RPL8, TP53, TTC35) are significantly altered with pancreatic tumor grades, which may contribute to differential expression of ferritin related to pancreatic cancer prognosis.

Are Serum Ferritin Levels a Reliable Cancer Biomarker? A Systematic Review and Meta-Analysis

Although serum ferritin (SF) has been shown in several studies to be a potential cancer biomarker, the results are inconsistent. Herein, a systematic review was performed to investigate the clinical SF levels in different types of tumors in order to verify the role of SF levels as a biomarker for cancer diagnosis. The search was performed using the PubMed/Medline, Cochrane Library, and Scopus databases. Observational studies comparing SF levels between healthy adults and patients with cancer were included. The meta-analysis was carried out according to the inverse variance and random effects model. The standardized mean differences (SMDs) were assessed at 95% confidence intervals (CIs). We found that SF was higher in patients with cancer (SMD 3.07; CI 1.96,4.17), especially for head and neck cancer (SMD 3.88; CI 0.42,7.34), lung cancer (SMD 1.72; CI 0.67,2.78), pancreatic cancer (SMD 6.79; CI 5.66,7.91), and renal cell carcinoma (SMD 1.77; CI 0.48,3.05). Moreover, in the advanced stages (Stages III and IV), ferritin levels were higher than in healthy adults (SMD 4.89; CI 2.72,7.06, and SMD 8.40; CI 6.99,9.82, respectively). SF acts as a biomarker for pancreatic cancer, renal cell carcinoma, lung cancer, and head and neck cancer and is a sensitive biomarker for the detection of advanced stages of tumors.

Emerging role of ferroptosis in breast cancer: New dawn for overcoming tumor progression

Breast cancer has become a serious threat to women's health. Cancer progression is mainly derived from resistance to apoptosis induced by procedures or therapies. Therefore, new drugs or models that can overcome apoptosis resistance should be identified. Ferroptosis is a recently identified mode of cell death characterized by excess reactive oxygen species-induced lipid peroxidation. Since ferroptosis is distinct from apoptosis, necrosis and autophagy, its induction successfully eliminates cancer cells that are resistant to other modes of cell death. Therefore, ferroptosis may become a new direction around which to design breast cancer treatment. Unfortunately, the complete appearance of ferroptosis in breast cancer has not yet been fully elucidated. Furthermore, whether ferroptosis inducers can be used in combination with traditional anti- breast cancer drugs is still unknown. Moreover, a summary of ferroptosis in breast cancer progression and therapy is currently not available. In this review, we discuss the roles of ferroptosis-associated modulators glutathione, glutathione peroxidase 4, iron, nuclear factor erythroid-2 related factor-2, superoxide dismutases, lipoxygenase and coenzyme Q in breast cancer. Furthermore, we provide evidence that traditional drugs against breast cancer induce ferroptosis, and that ferroptosis inducers eliminate breast cancer cells. Finally, we put forward prospect of using ferroptosis inducers in breast cancer therapy, and predict possible obstacles and corresponding solutions. This review will deepen our understanding of the relationship between ferroptosis and breast cancer, and provide new insights into breast cancer-related therapeutic strategies.

Ferritin heavy chain (FTH1) exerts significant antigrowth effects in breast cancer cells by inhibiting the expression of c-MYC

Overexpression of ferritin heavy chain (FTH1) often associates with good prognosis in breast cancer (BCa), particularly in the triple‐negative subtype (triple‐negative breast cancer). However, the mechanism by which FTH1 exerts its possible tumor suppressor effects in BCa is not known. Here, we examined the bearing of FTH1 silencing or overexpression on several aspects of BCa cell growth in vitro. FTH1 silencing promoted cell growth and mammosphere formation, increased c‐MYC expression, and reduced cell sensitivity to chemotherapy. In contrast, FTH1 overexpression inhibited cell growth, decreased c‐MYC expression, and sensitized cancer cells to chemotherapy; silencing of c‐MYC recapitulated the effects of FTH1 overexpression. These findings show for the first time that FTH1 suppresses tumor growth by inhibiting the expression of key oncogenes, such as c‐MYC.

Osteosarcoma in Children: Not Only Chemotherapy

Osteosarcoma (OS) is the most severe bone malignant tumor, responsible for altered osteoid deposition and with a high rate of metastasis. It is characterized by heterogeneity, chemoresistance and its interaction with bone microenvironment. The 5-year survival rate is about 67% for patients with localized OS, while it remains at 20% in case of metastases. The standard therapy for OS patients is represented by neoadjuvant chemotherapy, surgical resection, and adjuvant chemotherapy. The most used chemotherapy regimen for children is the combination of high-dose methotrexate, doxorubicin, and cisplatin. Considered that the necessary administration of high-dose chemotherapy is responsible for a lot of acute and chronic side effects, the identification of novel therapeutic strategies to ameliorate OS outcome and the patients' life expectancy is necessary. In this review we provide an overview on new possible innovative therapeutic strategies in OS.

Changes in the Mineral Composition of Rat Tissues Induced by Breast Cancer and Dietary Supplementation

BACKGROUND/AIM

The aim of the study was to determine the effect of various diets with zinc or zinc in combination with resveratrol or genistein on mineral contents of the serum, urine, liver, kidney and heart in rats with chemically-induced mammary carcinoma.

MATERIALS AND METHODS

The manuscript presents the tissues and body fluids content of iron, calcium, zinc, magnesium and copper in control rats or rats treated with 7,12-dimethyl-1,2-benz[a]anthracene to induce mammary carcinogenesis, under four dietary conditions: standard feed, Zn supplemented feed (6.9 mg Zn/ml), Zn and resveratrol (0.2 mg/kg body) supplemented feed, or Zn and genistein (0.2 mg/kg body) supplemented feed.

RESULTS

The content of calcium and copper highly varied depending on the tissue and the type of dietary supplement (no change for zinc and magnesium). Irrespective of the diet used, the chemical induction of mammary cancer caused a decrease in iron concentration in most samples analysed. Only supplementation of the rats' diet with zinc and genistein induced no changes in iron distribution in the serum, urine, liver, kidney and heart.

CONCLUSION

Further research using various levels of zinc and genistein in the diet should be conducted to determine how the development and progression of cancer is linked to iron content in cells and its ability to accumulate in tumour tissue.

Meta-analysis of the prognostic value of pretreatment serum ferritin in hepatobiliary and pancreas (HBP) cancers

BACKGROUND AND OBJECTIVES

Studies have shown that serum ferritin (SF) has unfavourable prognostic value in hepatobiliary and pancreas (HBP) cancers. This meta-analysis aimed to comprehensively assess the prognostic role of pretreatment SF in patients with HBP cancers.

METHODS

Eligible studies published before January 2020 were obtained through a comprehensive search in the PubMed, Web of Science, Cochrane Library and EMBASE databases. Pooled HRs and 95% CIs were then employed as effect sizes.

RESULTS

Seven studies comprising 1244 patients were pooled. Elevated pretreatment SF was associated with worse overall survival (OS) (HR 1.60, 95% CI 1.36 to 1.88, p<0.001) and recurrence-free survival/progression-free survival/time to recurrence (HR 1.70, 95% CI 1.15 to 2.52, p=0.008). Significant prognostic value of elevated pretreatment SF on OS was detected in the subgroups regardless of the cancer type, race, SF cut-off value, tumour-node-metastasis stage and Newcastle-Ottawa Scale score.

CONCLUSION

Elevated pretreatment SF was associated with worse survival outcome of patients with HBP cancers. As such, it may serve as a novel prognostic biomarker for HBP cancers.

Ciclopirox olamine induces ferritinophagy and reduces cyst burden in polycystic kidney disease

Despite the recent launch of tolvaptan, the search for safer polycystic kidney disease (PKD) drugs continues. Ciclopirox (CPX) or its olamine salt (CPX-O) is contained in a number of commercially available antifungal agents. CPX is also reported to possess anticancer activity. Several mechanisms of action have been proposed, including chelation of iron and inhibition of iron-dependent enzymes. Here, we show that CPX-O inhibited in vitro cystogenesis of primary human PKD cyst-lining epithelial cells cultured in a 3D collagen matrix. To assess the in vivo role of CPX-O, we treated PKD mice with CPX-O. CPX-O reduced the kidney-to-body weight ratios of PKD mice. The CPX-O treatment was also associated with decreased cell proliferation, decreased cystic area, and improved renal function. Ferritin levels were markedly elevated in cystic kidneys of PKD mice, and CPX-O treatment reduced renal ferritin levels. The reduction in ferritin was associated with increased ferritinophagy marker nuclear receptor coactivator 4, which reversed upon CPX-O treatment in PKD mice. Interestingly, these effects on ferritin appeared independent of iron. These data suggest that CPX-O can induce ferritin degradation via ferritinophagy, which is associated with decreased cyst growth progression in PKD mice. Most importantly these data indicate that CPX-O has the potential to treat autosomal dominant PKD.

TAM-ing the CIA-Tumor-Associated Macrophages and Their Potential Role in Unintended Side Effects of Therapeutics for Cancer-Induced Anemia

Cancer-induced anemia (CIA) is a common consequence of neoplasia and has a multifactorial pathophysiology. The immune response and tumor treatment, both intended to primarily target malignant cells, also affect erythropoiesis in the bone marrow. In parallel, immune activation inevitably induces the iron-regulatory hormone hepcidin to direct iron fluxes away from erythroid progenitors and into compartments of the mononuclear phagocyte system. Moreover, many inflammatory mediators inhibit the synthesis of erythropoietin, which is essential for stimulation and differentiation of erythroid progenitor cells to mature cells ready for release into the blood stream. These pathophysiological hallmarks of CIA imply that the bone marrow is not only deprived of iron as nutrient but also of erythropoietin as central growth factor for erythropoiesis. Tumor-associated macrophages (TAM) are present in the tumor microenvironment and display altered immune and iron phenotypes. On the one hand, their functions are altered by adjacent tumor cells so that they promote rather than inhibit the growth of malignant cells. As consequences, TAM may deliver iron to tumor cells and produce reduced amounts of cytotoxic mediators. Furthermore, their ability to stimulate adaptive anti-tumor immune responses is severely compromised. On the other hand, TAM are potential off-targets of therapeutic interventions against CIA. Red blood cell transfusions, intravenous iron preparations, erythropoiesis-stimulating agents and novel treatment options for CIA may interfere with TAM function and thus exhibit secondary effects on the underlying malignancy. In this Hypothesis and Theory, we summarize the pathophysiological hallmarks, clinical implications and treatment strategies for CIA. Focusing on TAM, we speculate on the potential intended and unintended effects that therapeutic options for CIA may have on the innate immune response and, consequently, on the course of the underlying malignancy.

Iron Metabolism in the Tumor Microenvironment: Contributions of Innate Immune Cells

Cells of the innate immune system are a major component of the tumor microenvironment. They play complex and multifaceted roles in the regulation of cancer initiation, growth, metastasis and responses to therapeutics. Innate immune cells like neutrophils and macrophages are recruited to cancerous tissues by chemotactic molecules released by cancer cells and cancer-associated stromal cells. Once they reach the tumor, they can be instructed by a network of proteins, nucleic acids and metabolites to exert protumoral or antitumoral functions. Altered iron metabolism is a feature of cancer. Epidemiological studies suggest that increased presence of iron and/or iron binding proteins is associated with increased risks of cancer development. It has been shown that iron metabolism is involved in shaping the immune landscapes in inflammatory/infectious diseases and cancer-associated inflammation. In this article, we will dissect the contribution of macrophages and neutrophils to dysregulated iron metabolism in malignant cells and its impact on cancer growth and metastasis. The mechanisms involved in regulating the actions of macrophages and neutrophils will also be discussed. Moreover, we will examine the effects of iron metabolism on the phenotypes of innate immune cells. Both iron chelating and overloading agents are being explored in cancer treatment. This review highlights alternative strategies for management of iron content in cancer cells by targeting the iron donation and modulation properties of macrophages and neutrophils in the tumor microenvironment.

Iron Metabolism in the Tumor Microenvironment-Implications for Anti-Cancer Immune Response

New insights into the field of iron metabolism within the tumor microenvironment have been uncovered in recent years. Iron promotes the production of reactive oxygen species, which may either trigger ferroptosis cell death or contribute to malignant transformation. Once transformed, cancer cells divert tumor-infiltrating immune cells to satisfy their iron demand, thus affecting the tumor immunosurveillance. In this review, we highlight how the bioavailability of this metal shapes complex metabolic pathways within the tumor microenvironment and how this affects both tumor-associated macrophages and tumor-infiltrating lymphocytes functions. Furthermore, we discuss the potentials as well as the current clinical controversies surrounding the use of iron metabolism as a target for new anticancer treatments in two opposed conditions: (i) the “hot” tumors, which are usually enriched in immune cells infiltration and are extremely rich in iron availability within the microenvironment, and (ii) the “cold” tumors, which are often very poor in immune cells, mainly due to immune exclusion.

Crosstalk between Macrophages, T Cells, and Iron Metabolism in Tumor Microenvironment

Leukocytes, including macrophages and T cells, represent key players in the human immune system, which plays a considerable role in the development and progression of tumors by immune surveillance or immune escape. Boosting the recruitment of leukocytes into the tumor microenvironment and promoting their antitumor responses have been hot areas of research in recent years. Although immunotherapy has manifested a certain level of success in some malignancies, the overall effectiveness is far from satisfactory. Iron is an essential trace element required in multiple, normal cellular processes, such as DNA synthesis and repair, cellular respiration, metabolism, and signaling, while dysregulated iron metabolism has been declared one of the metabolic hallmarks of malignant cancer cells. Furthermore, iron is implicated in the modulation of innate and adaptive immune responses, and elucidating the targeted regulation of iron metabolism may have the potential to benefit antitumor immunity and cancer treatment. In the present review, we briefly summarize the roles of leukocytes and iron metabolism in tumorigenesis, as well as their crosstalk in the tumor microenvironment. The combination of immunotherapy with targeted regulation of iron and iron-dependent regulated cell death (ferroptosis) may be a focus of future research.

Iron Dysregulation in Human Cancer: Altered Metabolism, Biomarkers for Diagnosis, Prognosis, Monitoring and Rationale for Therapy

Simple Summary

Iron is the more abundant metal ion in humans. It is essential for life as it has a role in various cellular processes involved, for instance, in cell metabolism and DNA synthesis. These functions are crucial for cell proliferation, and it is therefore not surprising that iron is accumulated in tumors. In this review, we describe normal and altered iron homeostasis mechanisms. We also provide a vision of iron-related proteins with altered expression in cancers and discuss their potential as diagnostic and/or prognostic biomarkers. Finally, we give an overview of therapeutic strategies acting on iron metabolism to fight against cancers.

Abstract

Iron (Fe) is a trace element that plays essential roles in various biological processes such as DNA synthesis and repair, as well as cellular energy production and oxygen transport, and it is currently widely recognized that iron homeostasis is dysregulated in many cancers. Indeed, several iron homeostasis proteins may be responsible for malignant tumor initiation, proliferation, and for the metastatic spread of tumors. A large number of studies demonstrated the potential clinical value of utilizing these deregulated proteins as prognostic and/or predictive biomarkers of malignancy and/or response to anticancer treatments. Additionally, the iron present in cancer cells and the importance of iron in ferroptosis cell death signaling pathways prompted the development of therapeutic strategies against advanced stage or resistant cancers. In this review, we select relevant and promising studies in the field of iron metabolism in cancer research and clinical oncology. Besides this, we discuss some co-existing discrepant findings. We also present and discuss the latest lines of research related to targeting iron, or its regulatory pathways, as potential promising anticancer strategies for human therapy. Iron chelators, such as deferoxamine or iron-oxide-based nanoparticles, which are already tested in clinical trials, alone or in combination with chemotherapy, are also reported.

Downregulation of Ubiquitin Inhibits the Aggressive Phenotypes of Esophageal Squamous Cell Carcinoma

Purpose:

Esophageal cancer is one of the most common malignancies worldwide. Ubiquitin-dependent degradation of regulatory proteins reportedly plays a central role in diverse cellular processes. This study investigated the expression levels of ubiquitin in esophageal squamous cell carcinoma tissues and the functions of ubiquitin in the context of esophageal squamous cell carcinoma progression.

Methods:

The expression of ubiquitin in esophageal squamous cell carcinoma and normal esophageal samples was determined via immunohistochemistry. Serum ubiquitin levels were determined by enzyme-linked immunosorbent assay. The association between serum ubiquitin level and clinicopathological factors was analyzed. Real-time PCR analysis was employed to measure the mRNA levels of the ubiquitin coding genes ubiquitin B and ubiquitin C. Proliferation assays, colony formation assays, and Transwell-based assays were used to determine the influence of ubiquitin on cell growth and cell invasion. Proteomic analysis was performed to identify the proteins associated with ubiquitin.

Results:

Ubiquitin expression in esophageal squamous cell carcinoma tissues was markedly higher than that in normal and tumor adjacent tissues. The levels of ubiquitin in esophageal squamous cell carcinoma serum samples were significantly higher than those in healthy controls. Serum ubiquitin levels were correlated with tumor stage and lymph node metastasis. To silence the expression of ubiquitin, we knocked down the ubiquitin coding genes ubiquitin B and ubiquitin C in TE-1 and Eca-109 cells. Silencing ubiquitin resulted in the suppression of cell growth, chemoresistance, colony formation and cell migration in esophageal squamous cell carcinoma cells. Proteomic analysis in esophageal squamous cell carcinoma cells showed that knockdown of ubiquitin coding genes deregulated the expression of 159 proteins (92 were upregulated and 67 were downregulated) involved in multiple pathways. These proteins included ferritin light chain, ferritin heavy chain, cellular retinoic acid-binding protein 2, and DNA replication factor 1.

Conclusion:

Ubiquitin expression is upregulated in esophageal squamous cell carcinoma tissues and serum samples. Serum ubiquitin levels were correlated with tumor stage and lymph node metastasis. Downregulation of ubiquitin suppresses the aggressive phenotypes of esophageal squamous cell carcinoma cells by complex mechanisms; ubiquitin may represent a novel target for the treatment of esophageal squamous cell carcinoma.

Targeting ferroptosis in breast cancer

Ferroptosis is a recently discovered distinct type of regulated cell death caused by the accumulation of lipid-based ROS. Metabolism and expression of specific genes affect the occurrence of ferroptosis, making it a promising therapeutic target to manage cancer. Here, we describe the current status of ferroptosis studies in breast cancer and trace the key regulators of ferroptosis back to previous studies. We also compare ferroptosis to common regulated cell death patterns and discuss the sensitivity to ferroptosis in different subtypes of breast cancer. We propose that viewing ferroptosis-related studies from a historical angle will accelerate the development of ferroptosis-based biomarkers and therapeutic strategies in breast cancer.

Nano-sensing and nano-therapy targeting central players in iron homeostasis

Iron plays vital roles in many life activities and it is strictly controlled via elaborate metabolic system. Growing evidence has suggested that the dysfunctional iron homeostasis is implicated to many refractory diseases including cancers and neurodegenerations. Systemic and cellular iron are regulated through different pathways but are meanwhile interconnecting with each other via a few key regulators, whose abnormal expressions are often found to be the root causes of many iron disorders. Nano-sensing techniques have enabled the detection and monitoring of such central players, which provide rich information for the iron homeostasis profile through multiplexing and flexible designs. In addition to general sensing, nanoprobes are capable of target imaging and precise local access, which are particularly beneficial for revealing the conditions of intra-/extracellular environments. Nanomaterials have also been applied in some therapies, targeting the aberrant iron metabolism. Various iron uptake pathways have been utilized for target drug delivery and iron level manipulation, while abnormal iron content is notably useful in tumor killing. With brief introduction to the significance of iron homeostasis, this review includes recent works regarding the nanotechnology that has been applied in iron-related diagnostic and therapeutic applications. This article is categorized under: Diagnostic Tools > Biosensing Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease Diagnostic Tools > in vivo Nanodiagnostics and Imaging.

Oxidative stress caused by lead (Pb) induces iron deficiency in Drosophila melanogaster

Toxic elements exposure disturbs the homeostasis of essential elements in organisms, but the mechanism remains elusive. In this study, we demonstrated that Drosophila melanogaster exposed to Lead (Pb, a pervasive environmental threat to human health) exhibited various health defects, including retarded development, decreased survival rate, impaired mobility and reduced egg production. These phenotypes could be significantly modulated by either intervention of dietary iron levels or altering expression of genes involved in iron metabolism. Further study revealed that Pb exposure leads to systemic iron deficiency. Strikingly, reactive oxygen species (ROS) clearance significantly increased iron uptake by restoring the expression of iron metabolism genes in the midgut and subsequently attenuated Pb toxicity. This study highlights the role of ROS in Pb induced iron dyshomeostasis and provides unique insights into understanding the mechanism of Pb toxicity and suggests ideal ways to attenuate Pb toxicity by iron supplementation therapy or ROS clearance.

The Disturbed Iron Phenotype of Tumor Cells and Macrophages in Renal Cell Carcinoma Influences Tumor Growth

Accumulating evidence suggests that iron homeostasis is disturbed in tumors. We aimed at clarifying the distribution of iron in renal cell carcinoma (RCC). Considering the pivotal role of macrophages for iron homeostasis and their association with poor clinical outcome, we investigated the role of macrophage-secreted iron for tumor progression by applying a novel chelation approach. We applied flow cytometry and multiplex-immunohistochemistry to detect iron-dependent markers and analyzed iron distribution with atomic absorption spectrometry in patients diagnosed with RCC. We further analyzed the functional significance of iron by applying a novel extracellular chelator using RCC cell lines as well as patient-derived primary cells. The expression of iron-regulated genes was significantly elevated in tumors compared to adjacent healthy tissue. Iron retention was detected in tumor cells, whereas tumor-associated macrophages showed an iron-release phenotype accompanied by enhanced expression of ferroportin. We found increased iron amounts in extracellular fluids, which in turn stimulated tumor cell proliferation and migration. In vitro, macrophage-derived iron showed pro-tumor functions, whereas application of an extracellular chelator blocked these effects. Our study provides new insights in iron distribution and iron-handling in RCC. Chelators that specifically scavenge iron in the extracellular space confirmed the importance of macrophage-secreted iron in promoting tumor growth.

Higher density of stromal M2 macrophages in breast ductal carcinoma in situ predicts recurrence

Immune response can affect tumour progression and treatment outcome. This study investigated the potential of stromal macrophages around ductal carcinoma in situ (DCIS) in predicting recurrence and progression. CD68 and CD163 expression of macrophages in DCIS from 198 patients was determined by immunohistochemistry. Disease free survival (DFS), clinicopathological parameters and biomarker expression were correlated with the densities of both CD68⁺ and CD163⁺ macrophages. High CD68⁺ macrophage density was associated with high nuclear grade (p < 0.001), oestrogen receptor (ER) negativity (p = 0.029), progesterone receptor (PR) negativity (p = 0.008) and human epidermal growth factor receptor 2 (HER2) positivity (p < 0.001). High CD163⁺ macrophage density was associated with high nuclear grade (p = 0.003), microinvasion (p = 0.01), ER negativity (p < 0.001), PR negativity (p = 0.001), HER2 positivity (p = 0.001) and triple negativity (p = 0.022). DCIS with higher CD68⁺ macrophage density disclosed significantly worse DFS for ipsilateral invasive recurrence (p = 0.004) and is affirmed by multivariate Cox regression analysis (95% CI 1.126-5.102, HR = 2.397, p = 0.023). DCIS with higher CD163⁺ macrophage density showed significantly worse DFS for both recurrence (p = 0.001) and ipsilateral invasive recurrence (p = 0.001). These findings, for CD163⁺ macrophage density, were affirmed by multivariate Cox regression analysis respectively for both recurrence (95% CI 1.210-2.293, HR = 1.880, p = 0.005) and ipsilateral invasive recurrence (95% CI 1.122-5.176, HR = 2.410, p = 0.024). This study demonstrated that DCIS with higher macrophage density was associated with poorer prognostic parameters, while DCIS with higher CD163⁺ macrophage density predicted both  recurrence and ipsilateral invasive recurrence.

Tumor-associated macrophages and individual chemo-susceptibility are influenced by iron chelation in human slice cultures of gastric cancer

Purpose: Presence of tumor-associated macrophages (TAM) and high levels of ferritin and lipocalin 2 (Lcn2) in the tumor microenvironment are associated with poor prognosis in many types of cancer. Here we investigate whether iron deprivation influences TAM phenotype and chemotherapy resistance in tumor slice cultures (TSC) of gastric cancer. Results: TAM remained morphologically and functionally stable for four DIV. DFO treatment for 72 h decreased ferritin expression in TAM and in the tumor stroma but did not alter Lcn2 expression. TAM phenotype was altered after 72 h of cisplatin or DFO treatment compared with control conditions. Single DFO treatment and combined treatment with cytotoxic drugs significantly increased tumor cell apoptosis in TSC of gastric cancer. Methods: TSC were manufactured by cutting tissue of gastric cancer resection specimens in 350 μm thick slices and cultivating them under standard conditions on a filter membrane, at an air-liquid interface. After 24 h ex vivo, TSC were treated with irinotecan (100 nM) or cisplatin (10 μM) alone and in combination with deferoxamine (DFO; 10 μM, 100 μM), respectively, for 72 h. After four days in vitro (DIV) the TSC were fixated with paraformaldehyde, paraffin embedded and analyzed by immunohistochemistry for apoptosis (cPARP), proliferation (Ki67), TAM (CD68, CD163), ferritin, and Lcn2 expression. Conclusions: TAM are well preserved and can be studied in TSC of gastric cancer. Iron deprivation significantly increased tumor cell apoptosis.

Ironing out Macrophage Immunometabolism

Over the last decade, increasing evidence has reinforced the key role of metabolic reprogramming in macrophage activation. In addition to supporting the specific immune response of different subsets of macrophages, intracellular metabolic pathways also directly control the specialized effector functions of immune cells. In this context, iron metabolism has been recognized as an important component of macrophage plasticity. Since macrophages control the availability of this essential metal, changes in the expression of genes coding for the major proteins of iron metabolism may result in different iron availability for the macrophage itself and for other cells in the microenvironment. In this review, we discuss how macrophage iron can also play a role in immunometabolism.

Ferritin-based anticancer metallodrug delivery: Crystallographic, analytical and cytotoxicity studies

The encapsulation of anticancer metal-based drugs within a protein nanocage represents a valuable strategy to improve the efficacy and selectivity of these compounds towards cancer cells. The preparation, characterization of the in vitro cytotoxicity and X-ray structures of several ferritin-metallodrug nanocomposites (mainly containing platinum-, ruthenium- and gold-based anticancer agents) are here reviewed. The molecular mechanisms of action of these Ft-metallodrug adducts are discussed and future directions in the field are outlined.

Prognostic Value of Ferritin-to-Hemoglobin Ratio in Patients with Advanced Non-Small-Cell Lung Cancer

Background: Among commonly used biomarkers that reflect overall health in patients with cancer, hemoglobin is an iron-containing, oxygen-carrying protein in red blood cells, and serum ferritin is an iron-storage protein. This study investigated the ability of the ferritin-to-hemoglobin ratio to predict survival in patients with advanced non-small-cell lung cancer (NSCLC).

Methods: The medical records of patients with pathologically confirmed advanced NSCLC were retrospectively reviewed. The ferritin level, hemoglobin level, and ferritin-to-hemoglobin ratio at the initiation of treatment were investigated. After descriptive analysis of the ferritin-to-hemoglobin ratio, the optimal diagnostic cutoff value for survival was determined using receiver operating characteristic analysis. After dichotomizing patients according to the optimal cutoff value, the prognostic effect of the ferritin-to-hemoglobin ratio was assessed. Overall survival (OS) was calculated using Kaplan-Meier analysis and compared using log-rank tests. Cox proportional hazards regression was used to evaluate the prognostic effect with respect to survival.

Results: Of the enrolled patients, 91.3% had stage IV NSCLC, 42.0% had an Eastern Cooperative Oncology Group-performance status (ECOG-PS) score of 2, and 56.5% previously underwent systemic chemotherapy. The median OS of enrolled patients was 11.5 months. The range of the ferritin-to-hemoglobin ratio was 0.6-294.2, and the optimal cutoff value of the ferritin-to-hemoglobin ratio for survival was 13.0 (sensitivity, 58.5%; specificity, 80.0%; area under the curve = 0.68; P = 0.004). The median OS of patients with a low ferritin-to-hemoglobin ratio (<13.0) was 19.7 months, whereas that of patients with a high ferritin-to-hemoglobin ratio (≥13.0) was 8.5 months (P < 0.001). After eliminating confounding factors such as age, sex, ECOG-PS, histologic type, and C-reactive protein level, a high ferritin-to-hemoglobin ratio was significantly associated with poor survival. The multivariate proportional hazards model revealed that the ferritin-to-hemoglobin ratio was an independent prognostic marker for survival (hazard ratio, 1.91; 95% confidence interval, 1.27-2.88; P = 0.002).

Conclusion: The ferritin-to-hemoglobin ratio, a potential parameter of tumor progression, was a significant prognostic factor for OS, with a direct correlation to survival time in patients with advanced NSCLC.

Hypoxia-induced tumor exosomes promote M2-like macrophage polarization of infiltrating myeloid cells and microRNA-mediated metabolic shift

Developing tumors rapidly outgrow their oxygen supply and are subject to hypoxia, which stimulates hypersecretion of tumor-derived exosomes that promote angiogenesis, metastasis, and immunosuppression, but the molecular mediators of these pathological effects remain poorly defined. Using quantitative proteomics, we identified that exosomes produced by hypoxic tumor cells are highly enriched in immunomodulatory proteins and chemokines including CSF-1, CCL2, FTH, FTL, and TGFβ. Modeling exosome effects on tumor-infiltrating immune cells, we observed a potent ability of these hypoxia-induced vesicles to influence macrophage recruitment and promote M2-like polarization both in vitro and in vivo. In addition, hypoxic, but not normoxic, tumor exosomes enhanced oxidative phosphorylation in bone marrow-derived macrophages via transfer of let-7a miRNA, resulting in suppression of the insulin-Akt-mTOR signaling pathway. Together, these data demonstrate that hypoxia promotes tumor secretion of biomolecule-loaded exosomes that can modify the immunometabolic profile of infiltrating monocyte-macrophages to better evade host immunity and enhance tumor progression.

Targeted Co-delivery of the Iron Chelator Deferoxamine and a HIF1α Inhibitor Impairs Pancreatic Tumor Growth

Rapidly growing cancer cells exhibit a strong dependence on iron for their survival. Thus, iron-removing drugs, iron chelators, have potential applications in cancer treatment. Deferoxamine (DFO) is an efficient iron chelator, but its short circulation half-life and ability to induce hypoxia-inducible factor 1α (HIF1α) overexpression restricts its use as an antitumor agent. In the present study, we first found that a pattern of iron-related protein expression favoring higher intracellular iron closely correlates with shorter overall and relapse-free survival in pancreatic cancer patients. We subsequently found that a combination of DFO and the HIF1α inhibitor, lificiguat (also named YC1), significantly enhanced the antitumor efficacy of DFO in vitro. We then employed transferrin receptor 1 (TFR1) targeting liposomes to codeliver DFO and YC1 to pancreatic tumors in a mouse model. The encapsulation of DFO prolonged its circulation time, improved its accumulation in tumor tissues via the enhanced permeability and retention (EPR) effect, and facilitated efficient uptake by cancer cells, which express high level of TFR1. After entering the tumor cells, the encapsulated DFO and YC1 were released to elicit a synergistic antitumor effect in subcutaneous and orthotopic pancreatic cancer xenografts. In summary, our work overcame two major obstacles in DFO-based cancer treatment through a simple liposome-based drug delivery system. This nanoencapsulation and targeting paradigm lays the foundation for future application of iron chelation in cancer therapy.

Serum Levels of Zinc, Copper and Ferritin in Patients with Salivary Gland Tumors

Background: Variation in serum levels of trace elements including zinc, copper and ferritin has been reported in cancer patients. The aim of this study was to evaluate these trace elements in the patients’ sera with benign and malignant salivary gland tumors (SGTs) and compare them with normal individuals. Methods: In this cross-sectional study, 60 patients with SGTs including 16 pleomorphic adenoma and 44 malignant SGTs, as well as 28 healthy controls, were enrolled. Serum levels of zinc, copper and ferritin were determined by atomic absorption and ELISA methods. Data were analyzed using one way ANOVA, Chi-square, Kruskal-Wallis and Mann- Whitney tests. Results: The mean concentration of zinc, copper, ferritin was1.5± 2 ppm, 1.2± 0.5 ppm, and 96.7± 65.7 ng/ml in PA, 1.5± 1.4,1.3± 0.4, and 111.2± 112 in malignant SGTs, and1.1±0.3, 1.2± 0.23 and 124±135.8 in normal control groups. There was no statistically significant difference between the patients and control groups, and between benign and malignant SGTs (P>0.05). Conclusion: The serum levels of trace elements in SGTs were not different from normal individuals. The results might have been affected by some interventional factors. Therefore, designing cohort complementary studies might result in obtaining more accurate data.

Iron as a Central Player and Promising Target in Cancer Progression

Iron is an essential element for virtually all organisms. On the one hand, it facilitates cell proliferation and growth. On the other hand, iron may be detrimental due to its redox abilities, thereby contributing to free radical formation, which in turn may provoke oxidative stress and DNA damage. Iron also plays a crucial role in tumor progression and metastasis due to its major function in tumor cell survival and reprogramming of the tumor microenvironment. Therefore, pathways of iron acquisition, export, and storage are often perturbed in cancers, suggesting that targeting iron metabolic pathways might represent opportunities towards innovative approaches in cancer treatment. Recent evidence points to a crucial role of tumor-associated macrophages (TAMs) as a source of iron within the tumor microenvironment, implying that specifically targeting the TAM iron pool might add to the efficacy of tumor therapy. Here, we provide a brief summary of tumor cell iron metabolism and updated molecular mechanisms that regulate cellular and systemic iron homeostasis with regard to the development of cancer. Since iron adds to shaping major hallmarks of cancer, we emphasize innovative therapeutic strategies to address the iron pool of tumor cells or cells of the tumor microenvironment for the treatment of cancer.

Screening, identification of prostate cancer urinary biomarkers and verification of important spots

Prostate-specific antigen (PSA) has been widely used as the unique serum biomarker for the diagnosis of prostate cancer (PCa). When PSA is moderately increased (e.g., 4-10 ng/ml), it is difficult to differentiate benign prostatic hyperplasia (BPH) from cancer. The diagnostic test (i.e., prostate biopsy) is invasive, adding pain and economic burden to the patient. Urine samples are more convenient, non-invasive and readily available than blood. We sought to determine whether ferritin might be the potential urinary biomarker in prostate cancer diagnosis. Using two-dimensional electrophoresis (2DE) followed by mass spectrometry (MS), differentially expressed urinary proteins among patients with PCa, BPH and normal controls were obtained. The ferritin heavy chain (FTH) gene, ferritin light chain (FTL) gene and protein expression of BPH-1 cells and PC-3 cells were analyzed by real-time quantitative PCR and Western blotting, respectively. Stable FTH or FTL silenced cell lines were generated by small hairpin(sh) RNA lentiviral transfection. The function of the cell lines was evaluated by the colony formation assay, transwell assay, and flow cytometry. Compared with BPH and normal controls, 15 overexpressed proteins, including FTH and FTL, were identified in the urine of the PCa group. FTH and FTL were also highly expressed in PC-3 cell lines compared with BPH-1 cells. FTH-silenced cells showed reduced cell proliferation, migration and increased cell apoptosis. FTL-silenced cells showed increased proliferation and migration abilities. There are differences in urinary proteins among patients with PCa, BPH and normal controls. FTH and FTL play different roles in PCa cells and are potential biomarkers for PCa.

An iron(iii) complex selectively mediated cancer cell death: crystal structure, DNA targeting and in vitro antitumor activities

Three new iron(iii) complexes were prepared, and complex 3 exhibited a 14-fold higher selectivity index for HeLa vs. LO2 normal cells than cisplatin.

Iron in the Tumor Microenvironment-Connecting the Dots

Iron metabolism and tumor biology are intimately linked. Iron facilitates the production of oxygen radicals, which may either result in iron-induced cell death, ferroptosis, or contribute to mutagenicity and malignant transformation. Once transformed, malignant cells require high amounts of iron for proliferation. In addition, iron has multiple regulatory effects on the immune system, thus affecting tumor surveillance by immune cells. For these reasons, inconsiderate iron supplementation in cancer patients has the potential of worsening disease course and outcome. On the other hand, chronic immune activation in the setting of malignancy alters systemic iron homeostasis and directs iron fluxes into myeloid cells. While this response aims at withdrawing iron from tumor cells, it may impair the effector functions of tumor-associated macrophages and will result in iron-restricted erythropoiesis and the development of anemia, subsequently. This review summarizes our current knowledge of the interconnections of iron homeostasis with cancer biology, discusses current clinical controversies in the treatment of anemia of cancer and focuses on the potential roles of iron in the solid tumor microenvironment, also speculating on yet unknown molecular mechanisms.