Upregulation of ZIP14 and Altered Zinc Homeostasis in Muscles in Pancreatic Cancer Cachexia

ZIP transporters-regulated Zn2+ homeostasis: A novel determinant of human diseases

As an essential trace element for organisms, zinc participates in various physiological processes, such as RNA transcription, DNA replication, cell proliferation, and cell differentiation. The destruction of zinc homeostasis is associated with various diseases. Zinc homeostasis is controlled by the cooperative action of zinc transporter proteins that are responsible for the influx and efflux of zinc. Zinc transporter proteins are mainly categorized into two families: Zrt/Irt-like protein (SLC39A/ZIP) family and zinc transporter (SLC30A/ZNT) family. ZIP transporters contain 14 members, namely ZIP1-14, which can be further divided into four subfamilies. Currently, ZIP transporters-regulated zinc homeostasis is one of the research hotspots. Cumulative evidence suggests that ZIP transporters-regulated zinc homeostasis may cause physiological dysfunction and contribute to the onset and progression of diverse diseases, such as cancers, neurological diseases, and cardiovascular diseases. In this review, we initially discuss the structure and distribution of ZIP transporters. Furthermore, we comprehensively review the latest research progress of ZIP transporters-regulated zinc homeostasis in diseases, providing a new perspective into new therapeutic targets for treating related diseases.

Cellular zinc metabolism and zinc signaling: from biological functions to diseases and therapeutic targets

Zinc metabolism at the cellular level is critical for many biological processes in the body. A key observation is the disruption of cellular homeostasis, often coinciding with disease progression. As an essential factor in maintaining cellular equilibrium, cellular zinc has been increasingly spotlighted in the context of disease development. Extensive research suggests zinc's involvement in promoting malignancy and invasion in cancer cells, despite its low tissue concentration. This has led to a growing body of literature investigating zinc's cellular metabolism, particularly the functions of zinc transporters and storage mechanisms during cancer progression. Zinc transportation is under the control of two major transporter families: SLC30 (ZnT) for the excretion of zinc and SLC39 (ZIP) for the zinc intake. Additionally, the storage of this essential element is predominantly mediated by metallothioneins (MTs). This review consolidates knowledge on the critical functions of cellular zinc signaling and underscores potential molecular pathways linking zinc metabolism to disease progression, with a special focus on cancer. We also compile a summary of clinical trials involving zinc ions. Given the main localization of zinc transporters at the cell membrane, the potential for targeted therapies, including small molecules and monoclonal antibodies, offers promising avenues for future exploration.

ZIP14 Affects the Proliferation, Apoptosis, and Migration of Cervical Cancer Cells by Regulating the P38 MAPK Pathway

BACKGROUND

Cervical cancer (CC) remains a major public health concern and is a leading cause of female mortality worldwide. Understanding the molecular basis of its pathogenesis is essential for the development of novel therapeutic strategies. In this study, we aimed to dissect the role of a specific molecule, ZIP14, in the initiation and progression of CC.

METHODS

We used Gene Expression Omnibus for target gene identification, while KEGG was used to delineate CC-related pathways. Proliferation, migration, and apoptosis levels in CC cells were assessed using CCK8, Transwell, and flow cytometry, respectively. The effect of the target genes on the in vivo tumorigenesis of CC cells was evaluated using the subcutaneous tumorigenesis assay.

RESULTS

ZIP14 (SLC39A14) was found to be underexpressed in CC samples. Our KEGG pathway analysis revealed the potential involvement of the P38 mitogen-activated protein kinase (MAPK) pathway in CC pathogenesis. Overexpression of ZIP14 in HeLa and Caski cells increased p38 phosphorylation, inhibited cell growth and migration, and enhanced apoptosis. Conversely, ZIP14 knockdown produced the opposite effects. Importantly, the bioeffects induced by ZIP14 overexpression could be counteracted by the p38 MAPK pathway inhibitor SB203580. In vivo experiments further confirmed the influence of ZIP14 on CC cell migration.

CONCLUSION

Our study is the first to elucidate the pivotal role of ZIP14 in the pathogenesis of CC, revealing its inhibitory effects through the activation of the p38 MAPK signaling pathway. The discovery not only provides a deeper understanding of CC's molecular underpinnings, but also highlights ZIP14 as a promising therapeutic target. As ZIP14 holds significant potential for therapeutic interventions, our findings lay a robust foundation for further studies and pave the way for the exploration of novel treatment modalities for cervical cancer.

Proteomics analysis of circulating small extracellular vesicles: Focus on the contribution of EVs to tumor metabolism

The term small extracellular vesicle (sEV) is a comprehensive term that includes any type of cell-derived, membrane-delimited particle that has a diameter < 200 nm, and which includes exosomes and smaller microvesicles. sEVs transfer bioactive molecules between cells and are crucial for cellular homeostasis and particularly during tumor development, where sEVs provide important contributions to the formation of the premetastic niche and to their altered metabolism. sEVs are thus legitimate targets for intervention and have also gained increasing interest as an easily accessible source of biomarkers because they can be rapidly isolated from serum/plasma and their molecular cargo provides information on their cell-of origin. To target sEVs that are specific for a given cell/disease it is essential to identify EV surface proteins that are characteristic of that cell/disease. Mass-spectrometry based proteomics is widely used for the identification and quantification of sEV proteins. The methods used for isolating the sEVs, preparing the sEV sample for proteomics analysis, and mass spectrometry analysis, can have a strong influence on the results and requires careful consideration. This review provides an overview of the approaches used for sEV proteomics and discusses the inherent compromises regarding EV purity versus depth of coverage. Additionally, it discusses the practical applications of the methods to unravel the involvement of sEVs in regulating the metabolism of pancreatic ductal adenocarcinoma (PDAC). The metabolic reprogramming in PDAC includes enhanced glycolysis, elevated glutamine metabolism, alterations in lipid metabolism, mitochondrial dysfunction and hypoxia, all of which are crucial in promoting tumor cell growth. A thorough understanding of these metabolic adaptations is imperative for the development of targeted therapies to exploit PDAC's vulnerabilities.

Anemia, Iron Deficiency, and Iron Regulators in Pancreatic Ductal Adenocarcinoma Patients: A Comprehensive Analysis

Anemia and iron deficiency (ID) are common complications in patients with pancreatic ductal adenocarcinoma (PDAC), but their underlying causes remain unclear. This study investigated the incidence and characteristics of anemia and micronutrient deficiencies in PDAC patients before initiating chemotherapy. A total of 103 PDAC patients were included, comprising 67 in the palliative and 36 in the adjuvant groups. The overall incidence of anemia was 42.7% (n = 44), with comparable rates in both groups. Normocytic and normochromic anemia were predominant, with mild and moderate cases observed in 32% and 10.7% of the cohort, respectively. ID was evident in 51.4% of patients, with absolute ID more frequent in the adjuvant than in the palliative group (19.4% vs. 13.4%). Functional ID occurred more often in the palliative than in the adjuvant group (41.8% vs. 25%). Vitamin B12 and folate deficiency occurred in <5% (n = 5) of patients. Furthermore, 8.7% (n = 9) of patients had chronic kidney disease and anemia. To elucidate mechanisms of iron deficiency, the study explored the expression of iron regulators (hepcidin (HEP), ferroportin (FPN), and ZIP14 protein) and mitochondrial mass in PDAC tissue with immunohistochemical (IHC) staining and Perl's Prussian blue to detect iron deposits on available tumor samples (n = 56). ZIP14 expression was significantly higher in less advanced tumors (p = 0.01) and correlated with mitochondrial mass (p < 0.001), potentially indicating its role in local iron homeostasis. However, no significant impact of tissue iron regulators on patient survival was observed. Perl's Prussian blue staining revealed iron deposits within macrophages, but not in pancreatic duct cells. Furthermore, the GEPIA database was used to compare mRNA expression of iron regulators (HEP, FPN, and ZIP14) and other genes encoding iron transport and storage, including Transferrin Receptor Protein 1 (TfR1) and both ferritin chain subunits (FTH and FTL), in PDAC and normal pancreatic samples. FPN, TfR1, FTH, and FTL showed higher expression in tumor tissues, indicating increased iron usage by cancer. ZIP14 expression was higher in the pancreas than in PDAC and was correlated with FPN expression. The study highlights the importance of baseline iron status assessment in managing PDAC patients due to the high incidence of anemia and iron deficiency. Furthermore, ZIP14, in addition to HEP and FPN, may play a crucial role in local iron homeostasis in PDAC patients, providing valuable insights into the underlying mechanisms of iron dysregulation.

Molecular mechanisms of cancer cachexia-related loss of skeletal muscle mass: data analysis from preclinical and clinical studies

Cancer cachexia is a systemic hypoanabolic and catabolic syndrome that diminishes the quality of life of cancer patients, decreases the efficiency of therapeutic strategies and ultimately contributes to decrease their lifespan. The depletion of skeletal muscle compartment, which represents the primary site of protein loss during cancer cachexia, is of very poor prognostic in cancer patients. In this review, we provide an extensive and comparative analysis of the molecular mechanisms involved in the regulation of skeletal muscle mass in human cachectic cancer patients and in animal models of cancer cachexia. We summarize data from preclinical and clinical studies investigating how the protein turnover is regulated in cachectic skeletal muscle and question to what extent the transcriptional and translational capacities, as well as the proteolytic capacity (ubiquitin-proteasome system, autophagy-lysosome system and calpains) of skeletal muscle are involved in the cachectic syndrome in human and animals. We also wonder how regulatory mechanisms such as insulin/IGF1-AKT-mTOR pathway, endoplasmic reticulum stress and unfolded protein response, oxidative stress, inflammation (cytokines and downstream IL1ß/TNFα-NF-κB and IL6-JAK-STAT3 pathways), TGF-ß signalling pathways (myostatin/activin A-SMAD2/3 and BMP-SMAD1/5/8 pathways), as well as glucocorticoid signalling, modulate skeletal muscle proteostasis in cachectic cancer patients and animals. Finally, a brief description of the effects of various therapeutic strategies in preclinical models is also provided. Differences in the molecular and biochemical responses of skeletal muscle to cancer cachexia between human and animals (protein turnover rates, regulation of ubiquitin-proteasome system and myostatin/activin A-SMAD2/3 signalling pathways) are highlighted and discussed. Identifying the various and intertwined mechanisms that are deregulated during cancer cachexia and understanding why they are decontrolled will provide therapeutic targets for the treatment of skeletal muscle wasting in cancer patients.

Relevant Membrane Transport Proteins as Possible Gatekeepers for Effective Pharmacological Ascorbate Treatment in Cancer

Despite the increasing number of newly diagnosed malignancies worldwide, therapeutic options for some tumor diseases are unfortunately still limited. Interestingly, preclinical but also some clinical data suggest that the administration of pharmacological ascorbate seems to respond well, especially in some aggressively growing tumor entities. The membrane transport and channel proteins are highly relevant for the use of pharmacological ascorbate in cancer therapy and are involved in the transfer of active substances such as ascorbate, hydrogen peroxide, and iron that predominantly must enter malignant cells to induce antiproliferative effects and especially ferroptosis. In this review, the relevant conveying proteins from cellular surfaces are presented as an integral part of the efficacy of pharmacological ascorbate, considering the already known genetic and functional features in tumor tissues. Accordingly, candidates for diagnostic markers and therapeutic targets are mentioned.

Dexamethasone leads to Zn2+ accumulation and increased unbound Zn2+ in C2C12 muscle and 3T3-L1 adipose cells

Skeletal muscle atrophy is associated with increases in circulating glucocorticoid levels and insulin resistance. Zinc accumulates in atrophic muscle, but the relationship between atrophy, insulin resistance, and Zn²⁺ homeostasis remains unclear. In this study, the effect of the glucocorticoid dexamethasone (DEX) on insulin and Zn²⁺ homeostasis was explored. Treatment of differentiated C2C12 skeletal myotubes and 3T3-L1 adipocytes with DEX significantly increased mRNA expression of the metal-binding proteins Mt1 and 2 and altered energy storage as shown by the increased size of lipid droplets in 3T3-L1 cells. In C2C12 cells the total cellular Zn²⁺ was higher after DEX treatment, and in both C2C12 and 3T3-L1 adipocytes, free unbound Zn²⁺ was increased. Insulin treatment led to a gradual increase in free Zn²⁺ in C2C12 cells, and no significant change in DEX-treated cells such that concentrations were similar 10 min after insulin treatment. These data demonstrate that DEX disturbs Zn²⁺ homeostasis in muscle and fat cells. Further study of the molecular pathways involved to identify novel therapeutic targets for treatment of skeletal muscle atrophy is warranted.

Role of noncoding RNAs in pancreatic ductal adenocarcinoma associated cachexia

Cachexia is an acute syndrome that is very commonly observed in patients with cancer. Cachexia is the number one cause of death in patients with metastatic disease and is also the major factor for physical toxicity and financial burden. More importantly, the majority of patients with advanced-stage pancreatic ductal adenocarcinoma (PDAC) cancer undergo cachexia. Pancreatic cancer causes deaths of ∼50,000 Americans and about 400,000 people worldwide every year. The high mortality rates in metastatic PDAC are due to systemic pathologies and cachexia, which quickens death in these patients. About 90% of all patients with PDAC undergo wasting of muscle causing mobility loss and leading to a number of additional pathological conditions. PDAC-associated cancer cachexia emanates from complex signaling cues involving both mechanical and biological signals. Tumor invasion is associated with the loss of pancreatic function-induced digestive disorders and malabsorption, which causes subsequent weight loss and eventually promotes cachexia. Besides, systemic inflammation of patients with PDAC could release chemical cues (e.g., cytokine-mediated Atrogin-1/MAFbx expression) that participate in muscle wasting. Our understanding of genes, proteins, and cytokines involved in promoting cancer cachexia has evolved considerably. However, the role of epigenetic factors, particularly the role of noncoding RNAs (ncRNAs) in regulating PDAC-associated cachexia is less studied. In this review article, the most updated knowledge on the various ncRNAs including microRNAs (miRs), long noncoding RNA (lncRNAs), piwi interacting RNAs (PiwiRNAs), small nucleolar RNA (snoRNAs), and circular RNAs (circRNA) and their roles in cancer cachexia are described.

Review of the endocrine organ-like tumor hypothesis of cancer cachexia in pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is one of the most fatal types of solid tumors, associated with a high prevalence of cachexia (~80%). PDAC-derived cachexia (PDAC-CC) is a systemic disease involving the complex interplay between the tumor and multiple organs. The endocrine organ-like tumor (EOLT) hypothesis may explain the systemic crosstalk underlying the deleterious homeostatic shifts that occur in PDAC-CC. Several studies have reported a markedly heterogeneous collection of cachectic mediators, signaling mechanisms, and metabolic pathways, including exocrine pancreatic insufficiency, hormonal disturbance, pro-inflammatory cytokine storm, digestive and tumor-derived factors, and PDAC progression. The complexities of PDAC-CC necessitate a careful review of recent literature summarizing cachectic mediators, corresponding metabolic functions, and the collateral impacts on wasting organs. The EOLT hypothesis suggests that metabolites, genetic instability, and epigenetic changes (microRNAs) are involved in cachexia development. Both tumors and host tissues can secrete multiple cachectic factors (beyond only inflammatory mediators). Some regulatory molecules, metabolites, and microRNAs are tissue-specific, resulting in insufficient energy production to support tumor/cachexia development. Due to these complexities, changes in a single factor can trigger bi-directional feedback circuits that exacerbate PDAC and result in the development of irreversible cachexia. We provide an integrated review based on 267 papers and 20 clinical trials from PubMed and ClinicalTrials.gov database proposed under the EOLT hypothesis that may provide a fundamental understanding of cachexia development and response to current treatments.

Muscle and Bone Defects in Metastatic Disease

PURPOSE OF REVIEW

The present review addresses most recently identified mechanisms implicated in metastasis-induced bone resorption and muscle-wasting syndrome, known as cachexia.

RECENT FINDINGS

Metastatic disease in bone and soft tissues is often associated with skeletal muscle defects. Recent studies have identified a number of secreted molecules and extracellular vesicles that contribute to cancer cell growth and metastasis leading to bone destruction and muscle atrophy. In addition, alterations in muscle microenvironment including dysfunctions in hepatic and mitochondrial metabolism have been implicated in cancer-induced regeneration defect and muscle loss. Moreover, we review novel in vitro and animal models including promising new drug candidates for bone metastases and cancer cachexia. Preservation of bone health could be highly beneficial for maintaining muscle mass and function. Therefore, a better understanding of molecular pathways implicated in bone and muscle crosstalk in metastatic disease may provide new insights and identify new strategies to improve current anticancer therapeutics.

PD-1 Alleviates Cisplatin-Induced Muscle Atrophy by Regulating Inflammation and Oxidative Stress

Skeletal muscle atrophy is an important characteristic of cachexia, which can be induced by chemotherapy and significantly contributes to functional muscle impairment. Inflammation and oxidative stress are believed to play important roles in the muscle atrophy observed in cachexia, but whether programmed cell death protein 1 (PD-1) is affected by this condition remains unclear. PD-1 is a membrane protein that is expressed on the surface of many immune cells and plays an important role in adaptive immune responses and autoimmunity. Thus, we investigated the role and underlying mechanism of PD-1 in cisplatin-induced muscle atrophy in mice. We found that PD-1 knockout dramatically contributed to skeletal muscle atrophy. Mechanistically, we found that E3 ubiquitin-protein ligases were significantly increased in PD-1 knockout mice after cisplatin treatment. In addition, we found that PD-1 knockout significantly exacerbated cisplatin-induced skeletal muscle inflammation and oxidative stress. Moreover, we found that there were significant increases in ferroptosis-related and autophagy-related genes in PD-1 knockout mice after cisplatin treatment. These data indicate that PD-1 plays an important role in cisplatin-induced skeletal muscle atrophy.

The crosstalk effect between ferrous and other ions metabolism in ferroptosis for therapy of cancer

Ferroptosis is an iron-dependent cell death process characterized by excessive accumulation of reactive oxygen species and lipid peroxidation. The elucidation of ferroptosis pathways may lead to novel cancer therapies. Current evidence suggests that the mechanism of ferroptosis can be summarized as oxidative stress and antioxidant defense mechanisms. During this process, ferrous ions play a crucial role in cellular oxidation, plasma membrane damage, reactive oxygen species removal imbalance and lipid peroxidation. Although, disregulation of intracellular cations (Fe²⁺, Ca²⁺, Zn²⁺, etc.) and anions (Cl^-, etc.) have been widely reported to be involved in ferroptosis, their specific regulatory mechanisms have not been established. To further understand the crosstalk effect between ferrous and other ions in ferroptosis, we reviewed the ferroptosis process from the perspective of ions metabolism. In addition, the role of ferrous and other ions in tumor therapy is briefly summarized.

Tumor cell anabolism and host tissue catabolism-energetic inefficiency during cancer cachexia

Cancer-associated cachexia (CC) is a pathological condition characterized by sarcopenia, adipose tissue depletion, and progressive weight loss. CC is driven by multiple factors such as anorexia, excessive catabolism, elevated energy expenditure by growing tumor mass, and inflammatory mediators released by cancer cells and surrounding tissues. In addition, endocrine system, systemic metabolism, and central nervous system (CNS) perturbations in combination with cachexia mediators elicit exponential elevation in catabolism and reduced anabolism in skeletal muscle, adipose tissue, and cardiac muscle. At the molecular level, mechanisms of CC include inflammation, reduced protein synthesis, and lipogenesis, elevated proteolysis and lipolysis along with aggravated toxicity and complications of chemotherapy. Furthermore, CC is remarkably associated with intolerance to anti-neoplastic therapy, poor prognosis, and increased mortality with no established standard therapy. In this context, we discuss the spatio-temporal changes occurring in the various stages of CC and highlight the imbalance of host metabolism. We provide how multiple factors such as proteasomal pathways, inflammatory mediators, lipid and protein catabolism, glucocorticoids, and in-depth mechanisms of interplay between inflammatory molecules and CNS can trigger and amplify the cachectic processes. Finally, we highlight current diagnostic approaches and promising therapeutic interventions for CC.

Synergistic Effects of Multiple Factors Involved in COVID-19-dependent Muscle Loss

The COVID-19 pandemic caused by the novel SARS-CoV-2 coronavirus is an ongoing pandemic causing severe health crisis worldwide. Recovered COVID-19 patients go through several long-term side effects such as fatigue, headaches, dizziness, weight loss, and muscle loss among others. Our study sought to determine the molecular mechanisms behind muscle loss in COVID-19 patients. We hypothesized that multiple factors such as cytokine storm and therapeutic drugs (glucocorticoid and antiviral drugs) might be involved in muscle loss. Using the Gene Expression Omnibus database, we identified several studies that performed RNA sequencing on skeletal muscles with the treatment of cytokine, glucocorticoid, and antiviral drugs. Our study identified cytokines, such as IL-1b, and IL-6, associated with altered regulation of several genes involved in the myogenic processes, including Ttn, Cxxc5, Malat1, and Foxo1. We also observed that glucocorticoid altered the expression of Foxo1, Lcn2, Slc39a14, and Cdkn1a. Finally, we found out that the antiviral (RNA-dependent RNA polymerase inhibitor) drug regulates the expression of some of the muscle-related genes (Txnip, Ccnd1, Hdac9, and Fbxo32). Based on our findings, we hypothesize that the cytokine storm, glucocorticoids, and antiviral drugs might be synergistically involved in COVID-19-dependent muscle loss.

Inhibitors of Human Divalent Metal Transporters DMT1 (SLC11A2) and ZIP8 (SLC39A8) from a GDB-17 Fragment Library

Solute carrier proteins (SLCs) are membrane proteins controlling fluxes across biological membranes and represent an emerging class of drug targets. Here we searched for inhibitors of divalent metal transporters in a library of 1,676 commercially available 3D-shaped fragment-like molecules from the generated database GDB-17, which lists all possible organic molecules up to 17 atoms of C, N, O, S and halogen following simple criteria for chemical stability and synthetic feasibility. While screening against DMT1 (SLC11A2), an iron transporter associated with hemochromatosis and for which only very few inhibitors are known, only yielded two weak inhibitors, our approach led to the discovery of the first inhibitor of ZIP8 (SLC39A8), a zinc transporter associated with manganese homeostasis and osteoarthritis but with no previously reported pharmacology, demonstrating that this target is druggable.

Ketogenic Diets in Pancreatic Cancer and Associated Cachexia: Cellular Mechanisms and Clinical Perspectives

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive and extremely therapy-resistant cancer. It is estimated that up to 80% of PDAC patients present with cachexia, a multifactorial disorder characterized by the involuntary and ongoing wasting of skeletal muscle that affects therapeutic response and survival. During the last decade, there has been an increased interest in exploring dietary interventions to complement the treatment of PDAC and associated cachexia. Ketogenic diets (KDs) have gained attention for their anti-tumor potential. Characterized by a very low carbohydrate, moderate protein, and high fat composition, this diet mimics the metabolic changes that occur in fasting. Numerous studies report that a KD reduces tumor growth and can act as an adjuvant therapy in various cancers, including pancreatic cancer. However, research on the effect and mechanisms of action of KDs on PDAC-associated cachexia is limited. In this narrative review, we summarize the evidence of the impact of KDs in PDAC treatment and cachexia mitigation. Furthermore, we discuss key cellular mechanisms that explain KDs’ potential anti-tumor and anti-cachexia effects, focusing primarily on reprogramming of cell metabolism, epigenome, and the gut microbiome. Finally, we provide a perspective on future research needed to advance KDs into clinical use.

Zinc transporter SLC39A13/ZIP13 facilitates the metastasis of human ovarian cancer cells via activating Src/FAK signaling pathway

BACKGROUND

Zinc transporters have been found to be associated with the pathogenesis of numerous human diseases including cancer. As the most lethal gynecologic malignancy, ovarian cancer is characterized by rapid progression and widespread metastases. However, the function and underlying mechanism of zinc transporters in ovarian cancer metastasis remain unclear.

METHODS

The relationship between zinc transporter gene expressions and clinical outcomes of ovarian cancer was assessed with the online database Kaplan-Meier plotter ( http://kmplot.com/analysis/ ). Immunohistochemistry was performed to investigate the prognostic importance of ZIP13. The expression of ZIP13 in ovarian cancer cell lines was depleted to explore its effect on proliferation, adhesion, migration, and invasion both in vitro and in vivo assays. RNA-Seq, quantitative RT-PCR, and western blot analysis were performed to explore ZIP13-regulated downstream target genes.

RESULTS

The expressions of several zinc transporters were highly associated the clinical outcomes of ovarian cancer patients. Among them, high ZIP13 expression was an independent prognostic factor for poor survival in patients with ovarian cancer. ZIP13 knockout suppressed the malignant phenotypes of ovarian cancer cells both in vitro and in vivo. Further investigation revealed that ZIP13 regulated intracellular zinc distribution and then affected the expressions of genes involved in extracellular matrix organization and cytokine-mediated signaling pathway. This led to the activation of Src/FAK pathway with increased expressions of pro-metastatic genes but decreased expressions of tumor suppressor genes.

CONCLUSIONS

ZIP13 is shown to be a novel driver of metastatic progression by modulating the Src/FAK signaling pathway, which may serve as a promising biomarker for prognostic evaluation and targeted therapy in ovarian cancer.

Integrative Management of Pancreatic Cancer (PDAC): Emerging Complementary Agents and Modalities

Pancreatic ductal adenocarcinoma (PDAC) is a devastating disease. The standard first-line treatment for PDAC is gemcitabine chemotherapy which, unfortunately, offers only limited chance of a lasting cure. This review further evaluates the hypothesis that the effectiveness of gemcitabine can be improved by combining it with evidence-based complementary measures. Previously, supported by clinical trial data, we suggested that a number of dietary factors and nutraceuticals can be integrated with gemcitabine therapy. Here, we evaluate a further 10 agents for which no clinical trials have (yet) been carried out but there are promising data from in vivo and/or in vitro studies including experiments involving combined treatments with gemcitabine. Two groups of complementary agents are considered: Dietary factors (resveratrol, epigallocatechin gallate, vitamin B9, capsaicin, quercetin and sulforaphane) and nutraceutical agents (artemisinin, garcinol, thymoquinone and emodin). In addition, we identified seven promising agents for which there is currently only basic (mostly in vitro) data. Finally, as a special case of combination therapy, we highlighted synergistic drug combinations involving gemcitabine with "repurposed" aspirin or metformin. We conclude overall that integrated management of PDAC currently is likely to produce the best outcome for patients and for this a wide range of complementary measures is available.

Phenotypic features of cancer cachexia-related loss of skeletal muscle mass and function: lessons from human and animal studies

Cancer cachexia is a complex multi-organ catabolic syndrome that reduces mobility, increases fatigue, decreases the efficiency of therapeutic strategies, diminishes the quality of life, and increases the mortality of cancer patients. This review provides an exhaustive and comprehensive analysis of cancer cachexia-related phenotypic changes in skeletal muscle at both the cellular and subcellular levels in human cancer patients, as well as in animal models of cancer cachexia. Cancer cachexia is characterized by a major decrease in skeletal muscle mass in human and animals that depends on the severity of the disease/model and the localization of the tumour. It affects both type 1 and type 2 muscle fibres, even if some animal studies suggest that type 2 muscle fibres would be more prone to atrophy. Animal studies indicate an impairment in mitochondrial oxidative metabolism resulting from a decrease in mitochondrial content, an alteration in mitochondria morphology, and a reduction in mitochondrial metabolic fluxes. Immuno-histological analyses in human and animal models also suggest that a faulty mechanism of skeletal muscle repair would contribute to muscle mass loss. An increase in collagen deposit, an accumulation of fat depot outside and inside the muscle fibre, and a disrupted contractile machinery structure are also phenotypic features that have been consistently reported in cachectic skeletal muscle. Muscle function is also profoundly altered during cancer cachexia with a strong reduction in skeletal muscle force. Even though the loss of skeletal muscle mass largely contributes to the loss of muscle function, other factors such as muscle-nerve interaction and calcium handling are probably involved in the decrease in muscle force. Longitudinal analyses of skeletal muscle mass by imaging technics and skeletal muscle force in cancer patients, but also in animal models of cancer cachexia, are necessary to determine the respective kinetics and functional involvements of these factors. Our analysis also emphasizes that measuring skeletal muscle force through standardized tests could provide a simple and robust mean to early diagnose cachexia in cancer patients. That would be of great benefit to cancer patient's quality of life and health care systems.

Understanding the common mechanisms of heart and skeletal muscle wasting in cancer cachexia

Cachexia is a severe complication of cancer that adversely affects the course of the disease, with currently no effective treatments. It is characterized by a progressive atrophy of skeletal muscle and adipose tissue, resulting in weight loss, a reduced quality of life, and a shortened life expectancy. Although the cachectic condition primarily affects the skeletal muscle, a tissue that accounts for ~40% of total body weight, cachexia is considered a multi-organ disease that involves different tissues and organs, among which the cardiac muscle stands out for its relevance. Patients with cancer often experience severe cardiac abnormalities and manifest symptoms that are indicative of chronic heart failure, including fatigue, shortness of breath, and impaired exercise tolerance. Furthermore, cardiovascular complications are among the major causes of death in cancer patients who experienced cachexia. The lack of effective treatments for cancer cachexia underscores the need to improve our understanding of the underlying mechanisms. Increasing evidence links the wasting of the cardiac and skeletal muscles to metabolic alterations, primarily increased energy expenditure, and to increased proteolysis, ensuing from activation of the major proteolytic machineries of the cell, including ubiquitin-dependent proteolysis and autophagy. This review aims at providing an overview of the key mechanisms of cancer cachexia, with a major focus on those that are shared by the skeletal and cardiac muscles.

Pancreatic Cancer and Cachexia-Metabolic Mechanisms and Novel Insights

Cachexia is a major characteristic of multiple non-malignant diseases, advanced and metastatic cancers and it is highly prevalent in pancreatic cancer, affecting almost 70-80% of the patients. Cancer cachexia is a multifactorial condition accompanied by compromised appetite and changes in body composition, i.e., loss of fat. It is associated with lower effectiveness of treatment, compromised quality of life, and higher mortality. Understanding the complex pathways underlying the pathophysiology of cancer cachexia, new therapeutic targets will be unraveled. The interplay between tumor and host factors, such as cytokines, holds a central role in cachexia pathophysiology. Cytokines are possibly responsible for anorexia, hypermetabolism, muscle proteolysis, and apoptosis. In particular, cachexia in pancreatic cancer might be the result of the surgical removal of pancreas parts. In recent years, many studies have been carried out to identify an effective treatment algorithm for cachexia. Choosing the most appropriate treatment, the clinical effect and the risk of adverse effects should be taken under consideration. The purpose of this review is to highlight the pathophysiological mechanisms as well as the current ways of cachexia treatment in the pharmaceutical and the nutrition field.

Understanding cachexia in the context of metastatic progression

Tumours reprogram host physiology, metabolism and immune responses during cancer progression. The release of soluble factors, exosomes and metabolites from tumours leads to systemic changes in distant organs, where cancer cells metastasize and grow. These tumour-derived circulating factors also profoundly impact tissues that are rarely inhabited by metastatic cancer cells such as skeletal muscle and adipose tissue. In fact, the majority of patients with metastatic cancer develop a debilitating muscle-wasting syndrome, known as cachexia, that is associated with decreased tolerance to antineoplastic therapy, poor prognosis and accelerated death, with no approved treatments. In this Perspective, we discuss the development of cachexia in the context of metastatic progression. We briefly discuss how circulating factors either directly or indirectly promote cachexia development and examine how signals from the metastatic process can trigger and amplify this process. Finally, we highlight promising therapeutic opportunities for targeting cachexia in the context of metastatic cancers.

Zinc dysregulation in cancers and its potential as a therapeutic target

Zinc is an essential element and serves as a structural or catalytic component in many proteins. Two families of transporters are involved in maintaining cellular zinc homeostasis: the ZIP (SLC39A) family that facilitates zinc influx into the cytoplasm, and the ZnT (SLC30A) family that facilitates zinc efflux from the cytoplasm. Zinc dyshomeostasis caused by the dysfunction of zinc transporters can contribute to the initiation or progression of various cancers, including prostate cancer, breast cancer, and pancreatic cancer. In addition, intracellular zinc fluctuations lead to the disturbance of certain signaling pathways involved in the malignant properties of cancer cells. This review briefly summarizes our current understanding of zinc dyshomeostasis in cancer, and discusses the potential roles of zinc or zinc transporters in cancer therapy.