Mediators of cachexia in cancer patients

Exosomes in the pathogenesis and treatment of cancer-related cachexia

Cancer-related cachexia is a metabolic syndrome characterized by weight loss, adipose tissue decomposition, and progressive skeletal muscle atrophy. It is a major complication of many advanced cancers and seriously affects the quality of life and survival of cancer patients. However, the specific molecules that mediate cancer-related cachexia remain elusive, and the fundamental cellular and molecular mechanisms associated with muscle atrophy and lipidolysis in cancer patients still need to be investigated. Exosomes, a newly discovered class of small extracellular vesicles that facilitate intercellular communication, have a significant role in the onset and development of various cancers. Studies have shown that exosomes play a role in the onset and progression of cancer-related cachexia by transporting active molecules such as nucleic acids and proteins. This review aimed to provide an overview of exosome developments in cancer-induced skeletal muscle atrophy and adipose tissue degradation. More importantly, exosomes were shown to have potential as diagnostic markers or therapeutic strategies for cachexia and were prospected, providing novel strategies for the diagnosis and treatment of cancer-related cachexia.

Molecular Mechanisms of Cachexia: A Review

Cachexia is a condition characterized by substantial loss of body weight resulting from the depletion of skeletal muscle and adipose tissue. A considerable fraction of patients with advanced cancer, particularly those who have been diagnosed with pancreatic or gastric cancer, lung cancer, prostate cancer, colon cancer, breast cancer, or leukemias, are impacted by this condition. This syndrome manifests at all stages of cancer and is associated with an unfavorable prognosis. It heightens the susceptibility to surgical complications, chemotherapy toxicity, functional impairments, breathing difficulties, and fatigue. The early detection of patients with cancer cachexia has the potential to enhance both their quality of life and overall survival rates. Regarding this matter, blood biomarkers, although helpful, possess certain limitations and do not exhibit universal application. Additionally, the available treatment options for cachexia are currently limited, and there is a lack of comprehensive understanding of the underlying molecular pathways associated with this condition. Thus, this review aims to provide an overview of molecular mechanisms associated with cachexia and potential therapeutic targets for the development of effective treatments for this devastating condition.

A triple-masked, two-center, randomized parallel clinical trial to assess the superiority of eight weeks of grape seed flour supplementation against placebo for weight loss attenuation during perioperative period in patients with cachexia associated with colorectal cancer: a study protocol

Background

Progressive, involuntary weight and lean mass loss in cancer are linked to cachexia, a prevalent syndrome in gastrointestinal malignancies that impacts quality of life, survival and postoperative complications. Its pathophysiology is complex and believed to involve proinflammatory cytokine-mediated systemic inflammation resulting from tumor-host interaction, oxidative stress, abnormal metabolism and neuroendocrine changes. Therapeutic options for cachexia remain extremely limited, highlighting the need for clinical research targeting new interventions. Thus, this study primarily assesses the effects of grape-seed flour (GSF), rich in polyphenols and fibers, for attenuating perioperative weight loss in colorectal cancer.

Methods

This is a dual-center, triple-masked, placebo-controlled, parallel-group, phase II, randomized clinical trial designed to investigate GSF supplementation in subjects with pre- or cachexia associated with colorectal cancer during the perioperative period. Eighty-two participants will receive 8g of GSF or cornstarch (control) for 8 weeks. Assessments are scheduled around surgery: pre-intervention (4 weeks prior), day before, first week after, and post-intervention (4 weeks later). The primary endpoint is the difference in body weight mean change from baseline to week 8. The secondary endpoints describe the harms from 8-week supplementation and assess its superiority to improve body composition, post-surgical complications, quality of life, anorexia, fatigue, gastrointestinal symptoms, and handgrip strength. The study will also explore its effects on gut bacteria activity and composition, systemic inflammation, and muscle metabolism.

Discussion

The current trial addresses a gap within the field of cancer cachexia, specifically focusing on the potential role of a nutritional intervention during the acute treatment phase. GSF is expected to modulate inflammation and oxidative stress, both involved in muscle and intestinal dysfunction. The research findings hold substantial implications for enhancing the understanding about cachexia pathophysiology and may offer a new clinical approach to managing cachexia at a critical point in treatment, directly impacting clinical outcomes.

Trial registration

The Brazilian Registry of Clinical Trials (ReBEC), RBR-5p6nv8b; UTN: U1111-1285-9594. Prospectively registered on February 07, 2023.

Cancer Cachexia: Underlying Mechanisms and Potential Therapeutic Interventions

Cancer cachexia, a multifactorial metabolic syndrome developed during malignant tumor growth, is characterized by an accelerated loss of body weight accompanied by the depletion of skeletal muscle mass. This debilitating condition is associated with muscle degradation, impaired immune function, reduced functional capacity, compromised quality of life, and diminished survival in cancer patients. Despite the lack of the known capability of fully reversing or ameliorating this condition, ongoing research is shedding light on promising preclinical approaches that target the disrupted mechanisms in the pathophysiology of cancer cachexia. This comprehensive review delves into critical aspects of cancer cachexia, including its underlying pathophysiological mechanisms, preclinical models for studying the progression of cancer cachexia, methods for clinical assessment, relevant biomarkers, and potential therapeutic strategies. These discussions collectively aim to contribute to the evolving foundation for effective, multifaceted counteractive strategies against this challenging condition.

Should oncologists trust cannabinoids?

Cannabis enjoyed a "golden age" as a medicinal product in the late 19th, early 20th century, but the increased risk of overdose and abuse led to its criminalization. However, the 21st century have witnessed a resurgence of interest and a large body of literature regarding the benefits of cannabinoids have emerged. As legalization and decriminalization have spread around the world, cancer patients are increasingly interested in the potential utility of cannabinoids. Although eager to discuss cannabis use with their oncologist, patients often find them to be reluctant, mainly because clinicians are still not convinced by the existing evidence-based data to guide their treatment plans. Physicians should prescribe cannabis only if a careful explanation can be provided and follow up response evaluation ensured, making it mandatory for them to be up to date with the positive and also negative aspects of the cannabis in the case of cancer patients. Consequently, this article aims to bring some clarifications to clinicians regarding the sometimes-confusing various nomenclature under which this plant is mentioned, current legislation and the existing evidence (both preclinical and clinical) for the utility of cannabinoids in cancer patients, for either palliation of the associated symptoms or even the potential antitumor effects that cannabinoids may have.

Necroptosis Mediates Muscle Protein Degradation in a Cachexia Model of Weanling Pig with Lipopolysaccharide Challenge

Necroptosis, an actively researched form of programmed cell death closely related to the inflammatory response, is important in a variety of disorders and diseases. However, the relationship between necroptosis and muscle protein degradation in cachexia is rarely reported. This study aimed to elucidate whether necroptosis played a crucial role in muscle protein degradation in a cachexia model of weaned piglets induced by lipopolysaccharide (LPS). In Experiment 1, the piglets were intraperitoneally injected with LPS to construct the cachexia model, and sacrificed at different time points after LPS injection (1, 2, 4, 8, 12, and 24 h). In Experiment 2, necrostatin-1 (Nec-1), a necroptosis blocker, was pretreated in piglets before the injection of LPS to inhibit the occurrence of necroptosis. Blood and longissimus dorsi muscle samples were collected for further analysis. In the piglet model with LPS-induced cachexia, the morphological and ultrastructural damage, and the release of pro-inflammatory cytokines including tumor necrosis factor (TNF)-α, interleukin (IL)-1β, and IL-6 were dynamically elicited in longissimus dorsi muscle. Further, protein concentration and protein/DNA ratio were dynamically decreased, and protein degradation signaling pathway, containing serine/threonine kinase (Akt), Forkhead box O (FOXO), muscular atrophy F-box (MAFbx), and muscle ring finger protein 1 (MuRF1), was dynamically activated in piglets after LPS challenge. Moreover, mRNA and protein expression of necroptosis signals including receptor-interacting protein kinase (RIP)1, RIP3, and mixed lineage kinase domain-like pseudokinase (MLKL), were time-independently upregulated. Subsequently, when Nec-1 was used to inhibit necroptosis, the morphological damage, the increase in expression of pro-inflammatory cytokines, the reduction in protein content and protein/DNA ratio, and the activation of the protein degradation signaling pathway were alleviated. These results provide the first evidence that necroptosis mediates muscle protein degradation in cachexia by LPS challenge.

Ursolic Acid Alleviates Cancer Cachexia and Prevents Muscle Wasting via Activating SIRT1

Skeletal muscle wasting is the most remarkable phenotypic feature of cancer cachexia that increases the risk of morbidity and mortality. However, there are currently no effective drugs against cancer cachexia. Ursolic acid (UA) is a lipophilic pentacyclic triterpene that has been reported to alleviate muscle atrophy and reduce muscle decomposition in some disease models. This study aimed to explore the role and mechanisms of UA treatment in cancer cachexia. We found that UA attenuated Lewis lung carcinoma (LLC)-conditioned medium-induced C2C12 myotube atrophy and muscle wasting of LLC tumor-bearing mice. Moreover, UA dose-dependently activated SIRT1 and downregulated MuRF1 and Atrogin-1. Molecular docking results revealed a good binding effect on UA and SIRT1 protein. UA rescued vital features wasting without impacting tumor growth, suppressed the elevated spleen weight, and downregulated serum concentrations of inflammatory cytokines in vivo. The above phenomena can be attenuated by Ex-527, an inhibitor of SIRT1. Furthermore, UA remained protective against cancer cachexia in the advanced stage of tumor growth. The results revealed that UA exerts an anti-cachexia effect via activating SIRT1, thereby downregulating the phosphorylation levels of NF-κB and STAT3. UA might be a potential drug against cancer cachexia.

Cancer-associated cachexia - understanding the tumour macroenvironment and microenvironment to improve management

Cachexia is a devastating, multifactorial and often irreversible systemic syndrome characterized by substantial weight loss (mainly of skeletal muscle and adipose tissue) that occurs in around 50-80% of patients with cancer. Although this condition mainly affects skeletal muscle (which accounts for approximately 40% of total body weight), cachexia is a multi-organ syndrome that also involves white and brown adipose tissue, and organs including the bones, brain, liver, gut and heart. Notably, cachexia accounts for up to 20% of cancer-related deaths. Cancer-associated cachexia is invariably associated with systemic inflammation, anorexia and increased energy expenditure. Understanding these mechanisms is essential, and the progress achieved in this area over the past decade could help to develop new therapeutic approaches. In this Review, we examine the currently available evidence on the roles of both the tumour macroenvironment and microenvironment in cancer-associated cachexia, and provide an overview of the novel therapeutic strategies developed to manage this syndrome.

Metabolic switch in cancer - Survival of the fittest

Cell metabolism is characterised by the highly coordinated conversion of nutrients into energy and biomass. In solid cancers, hypoxia, nutrient deficiencies, and tumour vasculature are incompatible with accelerated anabolic growth and require a rewiring of cancer cell metabolism. Driver gene mutations direct malignant cells away from oxidation to maximise energy production and biosynthesis while tumour-secreted factors degrade peripheral tissues to fuel disease progression and initiate metastasis. As it is vital to understand cancer cell metabolism and survival mechanisms, this review discusses the metabolic switch and current drug targets and clinical trials. In the future, metabolic markers may be included when phenotyping individual tumours to improve the therapeutic opportunities for personalised therapy.

Targeting cancer cachexia: Molecular mechanisms and clinical study

Cancer cachexia is a complex systemic catabolism syndrome characterized by muscle wasting. It affects multiple distant organs and their crosstalk with cancer constitute cancer cachexia environment. During the occurrence and progression of cancer cachexia, interactions of aberrant organs with cancer cells or other organs in a cancer cachexia environment initiate a cascade of stress reactions and destroy multiple organs including the liver, heart, pancreas, intestine, brain, bone, and spleen in metabolism, neural, and immune homeostasis. The role of involved organs turned from inhibiting tumor growth into promoting cancer cachexia in cancer progression. In this review, we depicted the complicated relationship of cancer cachexia with the metabolism, neural, and immune homeostasis imbalance in multiple organs in a cancer cachexia environment and summarized the treatment progress in recent years. And we discussed the molecular mechanism and clinical study of cancer cachexia from the perspective of multiple organs metabolic, neurological, and immunological abnormalities. Updated understanding of cancer cachexia might facilitate the exploration of biomarkers and novel therapeutic targets of cancer cachexia.

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.

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.

Clinical Relevance of Myopenia and Myosteatosis in Colorectal Cancer

Sarcopenia was initially described as a decrease in muscle mass associated with aging and subsequently also as a consequence of underlying disease, including advanced malignancy. Accumulating evidence shows that sarcopenia has clinically significant effects in patients with malignancy, including an increased risk of adverse events associated with medical treatment, postoperative complications, and a poor survival outcome. Colorectal cancer (CRC) is one of the most common cancers worldwide, and several lines of evidence suggest that preoperative sarcopenia negatively impacts various outcomes in patients with CRC. In this review, we summarize the current evidence in this field and the clinical relevance of sarcopenia in patients with CRC from three standpoints, namely, the adverse effects of medical treatment, postoperative infectious complications, and oncological outcomes.

Molecular Mechanisms and Current Treatment Options for Cancer Cachexia

Simple Summary

The primary characteristics of cancer cachexia are weakness, weight loss, atrophy, fat reduction, and systemic inflammation. Cachexia is strongly associated with cancers involving the lungs, pancreas, esophagus, stomach, and liver, which account for half of all cancer deaths. TGF-β, MSTN, activin, IGF-1/PI3K/AKT, and JAK-STAT signaling pathways are known to underlie muscle atrophy and cachexia. Anamorelin (appetite stimulation), megestrol acetate, eicosapentaenoic acid, phytocannabinoids, targeting MSTN/activin, and molecules targeting proinflammatory cytokines, such as TNF-α and IL-6, are being tested as treatment options for cancer cachexia.

Abstract

Cancer cachexia is a condition marked by functional, metabolic, and immunological dysfunctions associated with skeletal muscle (SM) atrophy, adipose tissue loss, fat reduction, systemic inflammation, and anorexia. Generally, the condition is caused by a variety of mediators produced by cancer cells and cells in tumor microenvironments. Myostatin and activin signaling, IGF-1/PI3K/AKT signaling, and JAK-STAT signaling are known to play roles in cachexia, and thus, these pathways are considered potential therapeutic targets. This review discusses the current state of knowledge of the molecular mechanisms underlying cachexia and the available therapeutic options and was undertaken to increase understanding of the various factors/pathways/mediators involved and to identify potential treatment options.

Chronic Inflammation in Obesity and Cancer Cachexia

Chronic inflammation has long been linked to obesity and related conditions such as type 2 diabetes and metabolic syndrome. According to current research, the increased risk of cancer in people with certain metabolic diseases may be due to chronic inflammation. Adipocytokines, which are pro-inflammatory cytokines secreted in excess, are elevated in many chronic metabolic diseases. Cytokines and inflammatory mediators, which are not directly linked to DNA, are important in tumorigenesis. Cachexia, a type of metabolic syndrome linked to the disease, is associated with a dysregulation of metabolic pathways. Obesity and cachexia have distinct metabolic characteristics, such as insulin resistance, increased lipolysis, elevated free fatty acids (FFA), and ceramide levels, which are discussed in this section. The goal of this research project is to create a framework for bringing together our knowledge of inflammation-mediated insulin resistance.

GDF-15 in tumor-derived exosomes promotes muscle atrophy via Bcl-2/caspase-3 pathway

Tumor-derived exosomes are emerging mediators of cancer cachexia, a kind of multifactorial syndrome characterized by serious loss of skeletal muscle mass and function. Our previous study had showed that microRNAs in exosomes of C26 colon tumor cells were involved in induction of muscle atrophy. Here, we focus on studying proteins in tumor-derived exosomes which might also contribute to the development of cancer cachexia. Results of comparing the protein profiles of cachexic C26 exosomes and non-cachexic MC38 exosomes suggested that growth differentiation factor 15 (GDF-15) was rich in C26 exosomes. Western blotting analysis confirmed the higher levels of GDF-15 in C26 cells and C26 exosomes, compared with that of MC38 cells. Results of animal study also showed that GDF-15 was rich in tumor tissues, serum exosomes, and gastrocnemius (GA) muscle tissues of C26 tumor-bearing mice. GDF-15 protein could directly induce muscle atrophy of cultured C2C12 myotubes via regulating Bcl-2/caspase-3 pathways. What’s more, overexpression of GDF-15 in MC38 cells could increase the potency of MC38 conditioned medium or exosomes in inducing muscle atrophy. Knockdown of GDF-15 in C26 cells decreased the potency of C26 conditioned medium or exosomes in inducing muscle atrophy. These results suggested that GDF-15 in tumor-derived exosomes could contribute to induction of muscle atrophy and also supported the possibility of targeting GDF-15 in treatment of cancer cachexia.

IL-17A contributes skeletal muscle atrophy in lung cancer-induced cachexia via JAK2/STAT3 pathway

Cachexia is a complex metabolic syndrome that occurs in approximately 50% of patients with cancer. Skeletal muscle atrophy is the primary clinical feature. Interleukin (IL)-17A, a pro-inflammatory factor, plays an important role in many chronic inflammatory diseases. Here, we describe a novel signaling pathway through which IL-17A induced muscle atrophy.We conducted a retrospective clinical study to investigate the relationship between IL-17A and the skeletal muscle index in patients with lung adenocarcinoma. We also investigated the involvement of JAK2/STAT3 signaling pathway regarding the main features of cachexia by injecting Lewis lung carcinoma (LLC) cells into C57BL/6 mice as a model to replicate cancer-induced cachexia. In vitro, C2C12 myotubes were treated with recombinant IL-17A, anti-IL-17A monoclonal antibody, STAT3 inhibitor AG490, and LLC-conditioned medium. Cell viability and aging was also evaluated. We found in cancer conditions, increased serum levels of IL-17A were related to muscle wasting. JAK2/STAT3 phosphorylation was observed in the muscle of LLC tumor-bearing mice, accompanied by decreased MHC/Myog levels and increased MuRF1/Atrogin-1 levels. Administration of anti-IL-17A monoclonal antibody and AG490 slowed muscle atrophy development. Consistent with the in vivo findings, C2C12 myotubes treated with IL-17A and LLC-conditioned medium demonstrated phosphorylated JAK2/STAT3 signaling, resulting in MHC loss and myotube atrophy. IL-17A also inhibited C2C12 cell proliferation, cell cycle breaking, and cellular senescence. Our results identify phosphorylation of IL-17A/JAK2/STAT3 signaling pathway appears to be an important component in the pathogenesis of LLC tumor-induced cachexia. Targeted therapy of IL-17A may be a promising approach to reduce skeletal muscle loss of patients with cancer.

Exercise-Based Interventions to Counteract Skeletal Muscle Mass Loss in People with Cancer: Can We Overcome the Odds?

Addressing skeletal muscle mass loss is an important focus in oncology research to improve clinical outcomes, including cancer treatment tolerability and survival. Exercise is likely a necessary component of muscle-mass-preserving interventions for people with cancer. However, randomized controlled trials with exercise that include people with cancer with increased susceptibility to more rapid and severe muscle mass loss are limited. The aim of the current review is to highlight features of cancer-related skeletal muscle mass loss, discuss the impact in patients most at risk, and describe the possible role of exercise as a management strategy. We present current gaps within the exercise oncology literature and offer several recommendations for future studies to support research translation, including (1) utilizing accurate and reliable body composition techniques to assess changes in skeletal muscle mass, (2) incorporating comprehensive assessments of patient health status to allow personalized exercise prescription, (3) coupling exercise with robust nutritional recommendations to maximize the impact on skeletal muscle outcomes, and (4) considering key exercise intervention features that may improve exercise efficacy and adherence. Ultimately, the driving forces behind skeletal muscle mass loss are complex and may impede exercise tolerability and efficacy. Our recommendations are intended to foster the design of high-quality patient-centred research studies to determine whether exercise can counteract muscle mass loss in people with cancer and, as such, improve knowledge on this topic.

Skeletal Muscle Deconditioning in Breast Cancer Patients Undergoing Chemotherapy: Current Knowledge and Insights From Other Cancers

Breast cancer represents the most commonly diagnosed cancer while neoadjuvant and adjuvant chemotherapies are extensively used in order to reduce tumor development and improve disease-free survival. However, chemotherapy also leads to severe off-target side-effects resulting, together with the tumor itself, in major skeletal muscle deconditioning. This review first focuses on recent advances in both macroscopic changes and cellular mechanisms implicated in skeletal muscle deconditioning of breast cancer patients, particularly as a consequence of the chemotherapy treatment. To date, only six clinical studies used muscle biopsies in breast cancer patients and highlighted several important aspects of muscle deconditioning such as a decrease in muscle fibers cross-sectional area, a dysregulation of protein turnover balance and mitochondrial alterations. However, in comparison with the knowledge accumulated through decades of intensive research with many different animal and human models of muscle atrophy, more studies are necessary to obtain a comprehensive understanding of the cellular processes implicated in breast cancer-mediated muscle deconditioning. This understanding is indeed essential to ultimately lead to the implementation of efficient preventive strategies such as exercise, nutrition or pharmacological treatments. We therefore also discuss potential mechanisms implicated in muscle deconditioning by drawing a parallel with other cancer cachexia models of muscle wasting, both at the pre-clinical and clinical levels.

Cancer Cachexia: Its Mechanism and Clinical Significance

The term “cachexia” is derived from the Greek words kakos (bad) and hexis (habit). Cachexia is a malnutrition associated with chronic diseases such as cancer, chronic heart failure, chronic renal failure, and autoimmune diseases, and is characterized by decreased skeletal muscle mass. Cancer cachexia is quite common in patients with advanced cancer. Weight loss is also a characteristic symptom of cancer cachexia, along with decreased skeletal muscle mass. As nutritional supplementation alone cannot improve cachexia, cytokines and tumor-derived substances have been attracting attention as its relevant factors. Cancer cachexia can be also associated with reduced chemotherapeutic effects, increased side effects and treatment interruptions, and even poorer survival. In 2011, a consensus definition of cachexia has been proposed, and the number of relevant research reports has increased significantly. However, the pathogenesis of cachexia is not fully understood, and there are currently few regulatory-approved standard treatments for cachexia. The main reason for this is that multiple etiologies are involved in the development of cachexia. In this review, we will outline the current status of cachexia, the mechanisms of which have been elucidated in recent years, especially from the perspective of advanced cancer.

The Effect of Mechanical Stretch on Myotube Growth Suppression by Colon-26 Tumor-Derived Factors

Preclinical models and in vitro experiments have provided valuable insight into the regulation of cancer-induced muscle wasting. Colon-26 (C26) tumor cells induce cachexia in mice, and conditioned media (CM) from these cells promotes myotube atrophy and catabolic signaling. While mechanical stimuli can prevent some effects of tumor-derived factors on myotubes, the impact of mechanical signaling on tumor-derived factor regulation of myosin heavy chain (MyHC) expression is not well understood. Therefore, we examined the effects of stretch-induced mechanical signaling on C2C12 myotube growth and MyHC expression after C26 CM exposure. C26 CM was administered to myotubes on day 5 of differentiation for 48 h. During the last 4 or 24 h of C26 CM exposure, 5% static uniaxial stretch was administered. C26 CM suppressed myotube growth and MyHC protein and mRNA expression. Stretch for 24 h increased myotube size and prevented the C26 CM suppression of MyHC-Fast protein expression. Stretch did not change suppressed MyHC mRNA expression. Stretch for 24 h reduced Atrogin-1/MAFbx, MuRF-1, and LC3B II/I ratio and increased integrin β1D protein expression and the myogenin-to-MyoD protein ratio. Stretch in the last 4 h of CM increased ERK1/2 phosphorylation but did not alter the CM induction of STAT3 or p38 phosphorylation. These results provide evidence that in myotubes pre-incubated with CM, the induction of mechanical signaling can still provide a growth stimulus and preserve MyHC-Fast protein expression independent of changes in mRNA expression.

Febuxostat reduces muscle wasting in tumor-bearing mice with LM8 osteosarcoma cells via inhibition of reactive oxygen species generation

Cachexic condition due to malignant tumors has been a challenging problem. The aim of this study is to analyze effects of febuxostat on both in vitro and in vivo models of the wasting of skeletal muscles, due to LM8 osteosarcoma cells. C2C12 myotubes were incubated in the conditioned medium of LM8. Febuxostat was added at a concentration of 3 µM and 30 µM, and ROS, diameter of myotubes, and expression of atrogin-1 were analyzed. Furthermore, an in vivo study was performed by subcutaneous injection of LM8 on C3H mice. Febuxostat was administered in the drinking water at 5 µg/ml, and 25 µg/ml. In addition, tumor-bearing mice without febuxostat (group TB) and control mice (group C) were established. At 4 weeks, body weight, wet weights of the gastrocnemius muscles, XO activity, 8-OHdG, and expression of TNF-α and IL-6 were evaluated. ROS generation, atrophy of myotubes, and upregulation of atrogin-1 were clearly observed in C2C12 myotubes following incubation in the conditioned medium. These pathological conditions were significantly inhibited by febuxostat administration. Furthermore, mice in group TB showed significant loss of body weight and muscle weight in which XO activity, 8-OHdG, and expression of IL-6 were significantly increased compared to those in group C. Febuxostat administration not only significantly improved the body weight and muscleweight, but also reduced markers of oxidative stress and pro-inflammatory cytokines. Febuxostat did not show anti-tumor effects. Febuxostat, which is clinically used for treatment of hyperuricemia, is effective against the wasting of the skeletal muscles induced by LM8 osteosarcoma cells.

Skeletal Muscle and Childhood Cancer: Where are we now and where we go from here

Skeletal muscle (muscle) is essential for physical health and for metabolic integrity, with sarcopenia (progressive muscle mass loss and weakness), a pre-curser of aging and chronic disease. Loss of lean mass and muscle quality (force generation per unit of muscle) in the general population are associated with fatigue, weakness, and slowed walking speed, eventually interfering with the ability to maintain physical independence, and impacting participation in social roles and quality of life. Muscle mass and strength impairments are also documented during childhood cancer treatment, which often persist into adult survivorship, and contribute to an aging phenotype in this vulnerable population. Although several treatment exposures appear to confer increased risk for loss of mass and strength that persists after therapy, the pathophysiology responsible for poor muscle quantity and quality is not well understood in the childhood cancer survivor population. This is partly due to limited access to both pediatric and adult survivor muscle tissue samples, and to difficulties surrounding non-invasive investigative approaches for muscle assessment. Because muscle accounts for just under half of the body's mass, and is essential for movement, metabolism and metabolic health, understanding mechanisms of injury responsible for both initial and persistent dysfunction is important, and will provide a foundation for intervention. The purpose of this review is to provide an overview of the available evidence describing associations between childhood cancer, its treatment, and muscle outcomes, identifying gaps in current knowledge.

Biomarkers for Cancer Cachexia: A Mini Review

Cancer cachexia is a common condition in many cancer patients, particularly those with advanced disease. Cancer cachexia patients are generally less tolerant to chemotherapies and radiotherapies, largely limiting their treatment options. While the search for treatments of this condition are ongoing, standards for the efficacy of treatments have yet to be developed. Current diagnostic criteria for cancer cachexia are primarily based on loss of body mass and muscle function. However, these criteria are rather limiting, and in time, when weight loss is noticeable, it may be too late for treatment. Consequently, biomarkers for cancer cachexia would be valuable adjuncts to current diagnostic criteria, and for assessing potential treatments. Using high throughput methods such as "omics approaches", a plethora of potential biomarkers have been identified. This article reviews and summarizes current studies of biomarkers for cancer cachexia.

Cancer-derived exosome miRNAs induce skeletal muscle wasting by Bcl-2-mediated apoptosis in colon cancer cachexia

Cancer cachexia is a kind of whole-body metabolic disorder syndrome accompanied by severe wasting of muscle tissue in which cancer exosomes may be involved. Analysis of clinical samples showed that the serum exosome concentrations were correlated with the development of cancer cachexia. Exosomes secreted by C26 cells could decrease the diameter of C2C12 myotubes in vitro and decrease mouse muscle strength and tibialis anterior (TA) muscle weight in vivo. GW4869, an inhibitor of exosome excretion, ameliorated muscle wasting in C26 tumor-bearing mice. MicroRNA (miRNA) sequencing (miRNA-seq) analysis suggested that miR-195a-5p and miR-125b-1-3p were richer in C26 exosomes than in exosomes secreted from MC38 cells (non-cachexic). Both miR-195a-5p and miR-125b-1-3p mimics could induce atrophy of C2C12 myoblasts. Downregulation of Bcl-2 and activation of the apoptotic signaling pathway were observed in C2C12 myoblasts transfected with miR-195a-5p and miR-125b-1-3p mimics, in the gastrocnemius muscle of C26 tumor-bearing mice and in the TA muscle injected with C26 exosomes. Results of dual-luciferase assay confirmed the targeting of miR-195a-5p/miR-125b-1-3p to Bcl-2. Overexpression of Bcl-2 successfully reversed atrophy of C2C12 myoblasts induced by the two miRNA mimics. These results suggested that cancer exosome enriched miRNAs might induce muscle atrophy by targeting Bcl-2-mediated apoptosis.

Cachexia as Evidence of the Mechanisms of Resistance and Tolerance during the Evolution of Cancer Disease

During its evolution, cancer induces changes in patients’ energy metabolism that strongly affect the overall clinical state and are responsible for cancer-related cachexia syndrome. To better understand the mechanisms underlying cachexia and its metabolic derangements, research efforts should focus on the events that are driven by the immune system activation during the evolution of neoplastic disease and on the phenomena of “resistance” and “tolerance” typically involved in the human body response against stress, pathogens, or cancer. Indeed, in the case where resistance is not able to eliminate the cancer, tolerance mechanisms can utilize the symptoms of cachexia (anemia, anorexia, and fatigue) to counteract unregulated cancer growth. These notions are also sustained by the evidence that cancer cachexia may be reversible if the resistance and tolerance phases are supported by appropriate antineoplastic treatments. Accordingly, there is no doubt that anticachectic therapies have an irreplaceable role in cases of reversible cancer cachexia where, if harmoniously associated with effective antineoplastic therapies, they can contribute to preserve the quality of life and improve prognosis. Such anticachectic treatments should be based on targeting the complex immunological, inflammatory, and metabolic pathways involved in the complex pathogenesis of cachexia. Meanwhile, the role of the anticachectic therapies is very different in the stage of irreversible cachexia when the available antineoplastic treatments are not able to control the disease and the resistance mechanisms fail with the prevalence of the tolerance phenomena. At this stage, they can be useful only to improve the quality of life, allowing the patient and their family to get a better awareness of the final phases of life, thereby opening to the best spiritual remodulation of the final event, death.

Targeting the Activin Receptor Signaling to Counteract the Multi-Systemic Complications of Cancer and Its Treatments

Muscle wasting, i.e., cachexia, frequently occurs in cancer and associates with poor prognosis and increased morbidity and mortality. Anticancer treatments have also been shown to contribute to sustainment or exacerbation of cachexia, thus affecting quality of life and overall survival in cancer patients. Pre-clinical studies have shown that blocking activin receptor type 2 (ACVR2) or its ligands and their downstream signaling can preserve muscle mass in rodents bearing experimental cancers, as well as in chemotherapy-treated animals. In tumor-bearing mice, the prevention of skeletal and respiratory muscle wasting was also associated with improved survival. However, the definitive proof that improved survival directly results from muscle preservation following blockade of ACVR2 signaling is still lacking, especially considering that concurrent beneficial effects in organs other than skeletal muscle have also been described in the presence of cancer or following chemotherapy treatments paired with counteraction of ACVR2 signaling. Hence, here, we aim to provide an up-to-date literature review on the multifaceted anti-cachectic effects of ACVR2 blockade in preclinical models of cancer, as well as in combination with anticancer treatments.

Exosomal microRNAs in cancer-related sarcopenia: Tumor-derived exosomal microRNAs in muscle atrophy

Cancer-associated sarcopenia is a complex metabolic syndrome marked by muscle mass wasting. Muscle wasting is a serious complication that is a primary contributor to cancer-related mortality. The underlying molecular mechanisms of cancer-associated sarcopenia have not been completely described to date. In general, evidence shows that the main pathophysiological alterations in sarcopenia are associated with the degradation of cellular components, an exceptional inflammatory secretome and mitochondrial dysfunction. Importantly, we highlight the prospect that several miRNAs carried by tumor-derived exosomes that have shown the ability to promote inflammatory secretion, activate catabolism, and even participate in the regulation of cellular degradation pathways can be delivered to and exert effects on muscle cells. In this review, we aim to describe the current knowledge about the functions of exosomal miRNAs in the induction of cancer-associated muscle wasting and propose potential treatment strategies.

Neuromuscular, Psychological, and Sleep Predictors of Cancer-Related Fatigue in Cancer Patients

BACKGROUND

Cancer-related fatigue (CRF) is the most reported side effect of cancer and its treatments. This distressing sense of exhaustion critically impairs quality of life and can persist for years after treatment completion. Mechanisms of CRF are multidimensional (eg, physical, psychological, or behavioral), suggesting the need for a complex assessment. Nevertheless, CRF remains assessed mainly with 1-dimensional questionnaires. The purpose of this study was to test whether neuromuscular parameters enhance a model including well-known predictors of CRF.

PATIENTS AND METHODS

Forty-five participants with cancer history completed self-assessment questionnaires about quality of life, CRF, sleep disturbances, and emotional symptoms. They also completed a 5-minute handgrip fatiguing test composed of 60 maximal voluntary contractions to assess neuromuscular fatigability. Hierarchical linear regression analyses were performed to determine whether the neuromuscular fatigability threshold improved the FA12 score prediction beyond that provided by anxiety/depression and sleep disturbances.

RESULTS

The hierarchical linear regression analysis evidenced that a model including anxiety/depression, sleep disturbances, and neuromuscular fatigability explained 56% of CRF variance. In addition, the results suggest that the mechanisms leading to CRF may be different from one person to another.

CONCLUSION

Results revealed that sleep disturbances, emotional symptoms, and neuromuscular fatigability were the most important CRF predictors in cancer patients. This information could be useful for healthcare professionals offering tailored, individual support to patients with CRF.

Cancer-Associated Muscle Wasting-Candidate Mechanisms and Molecular Pathways

Excessive muscle loss is commonly observed in cancer patients and its association with poor prognosis has been well-established. Cancer-associated sarcopenia differs from age-related wasting in that it is not responsive to nutritional intervention and exercise. This is related to its unique pathogenesis, a result of diverse and interconnected mechanisms including inflammation, disordered metabolism, proteolysis and autophagy. There is a growing body of evidence that suggests that the tumor is the driver of muscle wasting by its elaboration of mediators that influence each of these pro-sarcopenic pathways. In this review, evidence for these tumor-derived factors and putative mechanisms for inducing muscle wasting will be reviewed. Potential targets for future research and therapeutic interventions will also be reviewed.

Exercise as a therapy for cancer-induced muscle wasting

Cancer cachexia is a progressive disorder characterized by body weight, fat, and muscle loss. Cachexia induces metabolic disruptions that can be analogous and distinct from those observed in cancer, obscuring both diagnosis and treatment options. Inflammation, hypogonadism, and physical inactivity are widely investigated as systemic mediators of cancer-induced muscle wasting. At the cellular level, dysregulation of protein turnover and energy metabolism can negatively impact muscle mass and function. Exercise is well known for its anti-inflammatory effects and potent stimulation of anabolic signaling. Emerging evidence suggests the potential for exercise to rescue muscle's sensitivity to anabolic stimuli, reduce wasting through protein synthesis modulation, myokine release, and subsequent downregulation of proteolytic factors. To date, there is no recommendation for exercise in the management of cachexia. Given its complex nature, a multimodal approach incorporating exercise offers promising potential for cancer cachexia treatment. This review's primary objective is to summarize the growing body of research examining exercise regulation of cancer cachexia. Furthermore, we will provide evidence for exercise interactions with established systemic and cellular regulators of cancer-induced muscle wasting.

Marked Increased Production of Acute Phase Reactants by Skeletal Muscle during Cancer Cachexia

Simple Summary

Muscle wasting during cancer is recognized as an independent predictor of mortality. The aim of this study was to characterize the changes in the muscle secretome associated with cancer cachexia to gain a better understanding of the mechanisms involved and to identify secreted proteins which may reflect this wasting process. Our study demonstrated that skeletal muscle is a source of several acute phase reactants during cancer cachexia that may hold the key to a cachexia-specific signature. Future work will have to determine whether some of these acute phase reactants contribute to and/or reflect the muscle atrophy caused by cancer, therefore representing potential therapeutic targets and/or biomarkers of cancer cachexia.

Abstract

Loss of skeletal muscle mass in cancer cachexia is recognized as a predictor of mortality. This study aimed to characterize the changes in the muscle secretome associated with cancer cachexia to gain a better understanding of the mechanisms involved and to identify secreted proteins which may reflect this wasting process. The changes in the muscle proteome of the C26 model were investigated by label-free proteomic analysis followed by a bioinformatic analysis in order to identify potentially secreted proteins. Multiple reaction monitoring and Western blotting were used to verify the presence of candidate proteins in the circulation. Our results revealed a marked increased muscular production of several acute phase reactants (APR: Haptoglobin, Serine protease inhibitor A3N, Complement C3, Serum amyloid A-1 protein) which are released in the circulation during C26 cancer cachexia. This was confirmed in other models of cancer cachexia as well as in cancer patients. Glucocorticoids and proinflammatory cytokines are responsible for an increased production of APR by muscle cells. Finally, their muscular expressions are strongly positively correlated with body weight loss as well as the muscular induction of atrogens. Our study demonstrates therefore a marked increased production of APR by the muscle in cancer cachexia.

The Redox Balance: A Target for Interventions Against Muscle Wasting in Cancer Cachexia?

Significance: The management of cancer patients is frequently complicated by the occurrence of a complex syndrome known as cachexia. It is mainly characterized by muscle wasting, a condition that associates with enhanced protein breakdown and with negative energy balance. While the mechanisms underlying cachexia have been only partially elucidated, understanding the pathogenesis of muscle wasting in cancer hosts is mandatory to design new targeted therapeutic strategies. Indeed, most of cancer patients will experience cachexia during the course of their disease, and about 25% of cancer-related deaths are due to this syndrome, rather than to the tumor itself. Recent Advances: Compelling evidence suggests that an altered redox homeostasis likely contributes to cancer-induced muscle protein depletion, directly or indirectly activating the intracellular degradative pathways. In addition, oxidative stress impinges on both mitochondrial number and function; the other way round, altered mitochondria lead to enhanced redox imbalance, creating a vicious loop that eventually results in negative energy metabolism. Critical Issues: The present review focuses on the possibility that pharmacological and nonpharmacological strategies able to restore a physiologic redox balance could be useful components of treatment schedules aimed at counteracting cancer-induced muscle wasting. Future Directions: Exercise and the use of exercise mimetic drugs represent the most promising approaches capable of reinforcing the muscle antioxidant defenses of cancer patients. The results from ongoing and new clinical trials are needed to validate the preclinical studies and provide effective therapies for cancer cachexia. Antioxid. Redox Signal. 33, 542-558.

The Impact of Immune Cells on the Skeletal Muscle Microenvironment During Cancer Cachexia

Progressive weight loss combined with skeletal muscle atrophy, termed cachexia, is a common comorbidity associated with cancer that results in adverse consequences for the patient related to decreased chemotherapy responsiveness and increased mortality. Cachexia's complexity has provided a barrier for developing successful therapies to prevent or treat the condition, since a large number of systemic disruptions that can regulate muscle mass are often present. Furthermore, considerable effort has focused on investigating how tumor derived factors and inflammatory mediators directly signal skeletal muscle to disrupt protein turnover regulation. Currently, there is developing appreciation for understanding how cancer alters skeletal muscle's complex microenvironment and the tightly regulated interactions between multiple cell types. Skeletal muscle microenvironment interactions have established functions in muscle response to regeneration from injury, growth, aging, overload-induced hypertrophy, and exercise. This review explores the growing body of evidence for immune cell modulation of the skeletal muscle microenvironment during cancer-induced muscle wasting. Emphasis is placed on the regulatory network that integrates physiological responses between immune cells with other muscle cell types including satellite cells, fibroblast cells, and endothelial cells to regulate myofiber size and plasticity. The overall goal of this review is to provide an understanding of how different cell types that constitute the muscle microenvironment and their signaling mediators contribute to cancer and chemotherapy-induced muscle wasting.

Trabectedin and Lurbinectedin Extend Survival of Mice Bearing C26 Colon Adenocarcinoma, without Affecting Tumor Growth or Cachexia

Trabectedin (ET743) and lurbinectedin (PM01183) limit the production of inflammatory cytokines that are elevated during cancer cachexia. Mice carrying C26 colon adenocarcinoma display cachexia (i.e., premature death and body wasting with muscle, fat and cardiac tissue depletion), high levels of inflammatory cytokines and subsequent splenomegaly. We tested whether such drugs protected these mice from cachexia. Ten-week-old mice were inoculated with C26 cells and three days later randomized to receive intravenously vehicle or 0.05 mg/kg ET743 or 0.07 mg/kg PM01183, three times a week for three weeks. ET743 or PM01183 extended the lifespan of C26-mice by 30% or 85%, respectively, without affecting tumor growth or food intake. Within 13 days from C26 implant, both drugs did not protect fat, muscle and heart from cachexia. Since PM01183 extended the animal survival more than ET743, we analyzed PM01183 further. In tibialis anterior of C26-mice, but not in atrophying myotubes, PM01183 restrained the NF-κB/PAX7/myogenin axis, possibly reducing the pro-inflammatory milieu, and failed to limit the C/EBPβ/atrogin-1 axis. Inflammation-mediated splenomegaly of C26-mice was inhibited by PM01183 for as long as the treatment lasted, without reducing IL-6, M-CSF or IL-1β in plasma. ET743 and PM01183 extend the survival of C26-bearing mice unchanging tumor growth or cachexia but possibly restrain muscle-related inflammation and C26-induced splenomegaly.

Cancer cachexia and its pathophysiology: links with sarcopenia, anorexia and asthenia

Cancer cachexia is a multifactorial syndrome characterized by a progressive loss of skeletal muscle mass, along with adipose tissue wasting, systemic inflammation and other metabolic abnormalities leading to functional impairment. Cancer cachexia has long been recognized as a direct cause of complications in cancer patients, reducing quality of life and worsening disease outcomes. Some related conditions, like sarcopenia (age-related muscle wasting), anorexia (appetite loss) and asthenia (reduced muscular strength and fatigue), share some key features with cancer cachexia, such as weakness and systemic inflammation. Understanding the interplay and the differences between these conditions is critical to advance basic and translational research in this field, improving the accuracy of diagnosis and contributing to finally achieve effective therapies for affected patients.

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.

Non-coding RNAs as Putative Biomarkers of Cancer-Associated Cachexia

Cachexia is a complex metabolic syndrome that determines a severe body weight loss characterized by a marked reduction in muscle mass. About 80% of patients with advanced cancer develop cachexia due to both the tumor itself and cancer treatment (radiotherapy and/or chemotherapy), which is associated to a worse prognosis. Despite its clinical relevance, this syndrome is still under-diagnosed and it lacks effective treatments. Radio-chemotherapy treatment is essential in patients with advanced head and neck cancers (HNSCC). Although this treatment has improved patients' life expectancy, it has also dramatically increased their need for assistance and support. The management of adverse symptoms, including cachexia, is of great importance in order to avoid delays in therapy, reduction of dosages and hospitalizations. MicroRNAs (miRNAs) are small non-coding RNA molecules, which have emerged as powerful biomarkers in stratifying human cancers. Due to their high stability in body fluids, miRNAs might be excellent non-invasive biomarkers for the early detection and follow-up of cancer patients. Here, we will summarize the current knowledge and debate the strong need to identify circulating biomarkers for the early diagnosis of cachexia. We will propose circulating non-coding RNAs as biomarkers for detecting early cachexia and implementing specific treatment. We will also discuss the potential use of circulating miRNAs as biomarkers of cachexia in HNSCC patients' blood samples collected before and after radio-chemotherapy treatment. Our intent is to pave the way to the identification of specific circulating miRNAs associated to cachexia occurrence and to the design of specific interventions aimed at improving the quality of life of cancer patients.

Promising models for cancer-induced cachexia drug discovery

Introduction: Cachexia is a frequent, multifactorial syndrome associated with cancer afflicting patients' quality of life, their ability to tolerate anti-neoplastic therapies and the therapies efficacy, as well as survival. Currently, there are no approved cancer cachexia treatments other than those for the treatment of the underlying cancer. Cancer cachexia (CC) is poorly understood and hence makes clinical trial design difficult at best. This underlines the importance of well-characterized animal models to further elucidate the pathophysiology of CC and drug discovery/development.Areas covered: This review gives an overview of the available animal models and their value and limitations in translational studies.Expert opinion: Using more than one CC model to test research questions or novel compounds/treatment strategies is strongly advisable. The main reason is that models have unique signaling modalities driving cachexia that may only relate to subgroups of cancer patients. Human xenograph CC models require the use of mice with a compromised immune system, limiting their value for translational experiments. It may prove beneficial to include standard care chemotherapy in the experimental design, as many chemotherapeutic agents can induce cachexia themselves and alter the metabolic and signaling derangements of CC and thus the response to new therapeutic strategies.

The Use of Proton Pump Inhibitors May Increase Symptoms of Muscle Function Loss in Patients with Chronic Illnesses

Long-term use of proton pump inhibitors (PPIs) is common in patients with muscle wasting-related chronic diseases. We explored the hypothesis that the use of PPIs may contribute to a reduction in muscle mass and function in these patients. Literature indicates that a PPI-induced reduction in acidity of the gastrointestinal tract can decrease the absorption of, amongst others, magnesium. Low levels of magnesium are associated with impaired muscle function. This unwanted side-effect of PPIs on muscle function has been described in different disease backgrounds. Furthermore, magnesium is necessary for activation of vitamin D. Low vitamin D and magnesium levels together can lead to increased inflammation involved in muscle wasting. In addition, PPI use has been described to alter the microbiota’s composition in the gut, which might lead to increased inflammation. However, PPIs are often provided together with nonsteroidal anti-inflammatory drugs (NSAIDs), which are anti-inflammatory. In the presence of obesity, additional mechanisms could further contribute to muscle alterations. In conclusion, use of PPIs has been reported to contribute to muscle function loss. Whether this will add to the risk factor for development of muscle function loss in patients with chronic disease needs further investigation.

Association between ANGPTL-4 and the proinflammatory process in cancer cachexia patients

Background

Contradictory results are reported for the role of angiopoietin-like 4 (ANGPTL-4) in the development of cancer-cachexia and inflammation, given its importance in angiogenesis and inflammatory signaling. Our aim was to analyze the levels of ANGPTL-4 in colorectal cancer patients with a stable weight and those with cachexia in order to establish a relationship between ANGPTL-4 and the inflammatory process.

Results

Plasma and tumor levels of ANGPTL-4 were higher in CC in comparison to other groups. A positive association was verified between plasmatic ANGPTL-4 and NFκB levels in tumor from CC. In WSC, we identified an association between the plasmatic ANGPTL-4, IL-15, and IL-10 in tumor and IL-15 in MES. Increased levels of NFκB and TNF-R1 in MES were detected in CC in comparison to WSC. Specifically in CC-group, a positive correlation was found between ANGPTL-4 levels and those of IL-1β, TNF-α, and NFκB in tumor, along with an association between ANGPTL-4 levels with IL-1β and MCP-1 levels in tumor; and ANGPTL-4 and IL-1β levels in MES.

Methods

We studied 102 patients, who were divided into three groups: control patients (C, n=37), cancer patients with a stable weight (WSC, n=23), and cancer-cachexia patients (CC, n=42). Samples of plasma, tumor, mesenteric (MES) and subcutaneous adipose tissue were removed for the determination of ANGPTL-4 levels and other proinflammatory factors.

Conclusions

ANGPTL-4 levels were higher in plasma and tumor of CC-group, and positively associated with pro-inflammatory and pro-tumorigenic factors. Our results suggest an opposite effect of ANGPTL-4 depending on the concentration and presence of cachexia.

Cachexia Anorexia Syndrome and Associated Metabolic Dysfunction in Peritoneal Metastasis

Patients with peritoneal metastasis (PM) of gastrointestinal and gynecological origin present with a nutritional deficit characterized by increased resting energy expenditure (REE), loss of muscle mass, and protein catabolism. Progression of peritoneal metastasis, as with other advanced malignancies, is associated with cancer cachexia anorexia syndrome (CAS), involving poor appetite (anorexia), involuntary weight loss, and chronic inflammation. Eventual causes of mortality include dysfunctional metabolism and energy store exhaustion. Etiology of CAS in PM patients is multifactorial including tumor growth, host response, cytokine release, systemic inflammation, proteolysis, lipolysis, malignant small bowel obstruction, ascites, and gastrointestinal side effects of drug therapy (chemotherapy, opioids). Metabolic changes of CAS in PM relate more to a systemic inflammatory response than an adaptation to starvation. Metabolic reprogramming is required for cancer cells shed into the peritoneal cavity to resist anoikis (i.e., programmed cell death). Profound changes in hexokinase metabolism are needed to compensate ineffective oxidative phosphorylation in mitochondria. During the development of PM, hypoxia inducible factor-1α (HIF-1α) plays a key role in activating both aerobic and anaerobic glycolysis, increasing the uptake of glucose, lipid, and glutamine into cancer cells. HIF-1α upregulates hexokinase II, phosphoglycerate kinase 1 (PGK1), pyruvate dehydrogenase kinase (PDK), pyruvate kinase muscle isoenzyme 2 (PKM2), lactate dehydrogenase (LDH) and glucose transporters (GLUT) and promotes cytoplasmic glycolysis. HIF-1α also stimulates the utilization of glutamine and fatty acids as alternative energy substrates. Cancer cells in the peritoneal cavity interact with cancer-associated fibroblasts and adipocytes to meet metabolic demands and incorporate autophagy products for growth. Therapy of CAS in PM is challenging. Optimal nutritional intake alone including total parenteral nutrition is unable to reverse CAS. Pressurized intraperitoneal aerosol chemotherapy (PIPAC) stabilized nutritional status in a significant proportion of PM patients. Agents targeting the mechanisms of CAS are under development.