Altered cardiac muscle mTOR regulation during the progression of cancer cachexia in the ApcMin/+ mouse

Anabolic deficits and divergent unfolded protein response underlie skeletal and cardiac muscle growth impairments in the Yoshida hepatoma tumor model of cancer cachexia

Cancer cachexia manifests as whole body wasting, however, the precise mechanisms governing the alterations in skeletal muscle and cardiac anabolism have yet to be fully elucidated. In this study, we explored changes in anabolic processes in both skeletal and cardiac muscles in the Yoshida AH-130 ascites hepatoma model of cancer cachexia. AH-130 tumor-bearing rats experienced significant losses in body weight, skeletal muscle, and heart mass. Skeletal and cardiac muscle loss was associated with decreased ribosomal (r)RNA, and hypophosphorylation of the eukaryotic factor 4E binding protein 1. Endoplasmic reticulum stress was evident by higher activating transcription factor mRNA in skeletal muscle and growth arrest and DNA damage-inducible protein (GADD)34 mRNA in both skeletal and cardiac muscles. Tumors provoked an increase in tissue expression of interferon-γ in the heart, while an increase in interleukin-1β mRNA was apparent in both skeletal and cardiac muscles. We conclude that compromised skeletal muscle and heart mass in the Yoshida AH-130 ascites hepatoma model involves a marked reduction translational capacity and efficiency. Furthermore, our observations suggest that endoplasmic reticulum stress and tissue production of pro-inflammatory factors may play a role in the development of skeletal and cardiac muscle wasting.

Astaxanthin Ameliorates Skeletal Muscle Atrophy in Mice With Cancer Cachexia

Astaxanthin (AST) is a natural marine carotenoid with a variety of biological activities. This study aimed to demonstrate the possible mechanisms by which AST improves skeletal muscle atrophy in cancer cachexia. In this study, the effects of different doses of AST (30 mg/kg b.w., 60 mg/kg b.w. and 120 mg/kg b.w.) on skeletal muscle functions were explored in mice with cancer cachexia. The results showed that AST (30, 60 and 120 mg/kg b.w.) could effectively protect cachexia mice from body weight and skeletal muscle loss. AST dose-dependently ameliorated the decrease in myofibres cross-sectional area and increased the expression of myosin heavy chain (MHC). AST treatment decreased both the serum and muscle level of IL-6 but not TNF-α in C26 tumor-bearing cachexia mice. Moreover, AST alleviated skeletal muscle atrophy by decreasing the expression of two muscle-specific E3 ligases MAFBx and MuRF-1. AST improved mitochondrial function by downregulating the levels of muscle Fis1, LC3B and Bax, upregulating the levels of muscle Mfn2 and Bcl-2. In conclusion, our study show that AST might be expected to be a nutritional supplement for cancer cachexia patients.

The pathophysiology of cancer-mediated cardiac cachexia and novel treatment strategies: A narrative review

SIGNIFICANCE

Two of the leading causes of death worldwide are cancer and cardiovascular diseases. Most cancer patients suffer from a metabolic wasting syndrome known as cancer-induced cardiac cachexia, resulting in death in up to 30% of cancer patients. Main symptoms of this disease are severe cardiac muscle wasting, cardiac remodeling, and cardiac dysfunction. Metabolic alterations, increased inflammation, and imbalance of protein homeostasis contribute to the progression of this multifactorial syndrome, ultimately resulting in heart failure and death. Cancer-induced cardiac cachexia is associated with decreased quality of life, increased fatiguability, and decreased tolerance to therapeutic interventions.

RECENT ADVANCES

While molecular mechanisms of this disease are not fully understood, researchers have identified different stages of progression of this disease, as well as potential biomarkers to detect and monitor the development. Preclinical and clinical studies have shown positive results when implementing certain pharmacological and non-pharmacological therapy interventions.

CRITICAL ISSUES

There are still no clear diagnostic criteria for cancer-mediated cardiac cachexia and the condition remains untreated, leaving cancer patients with irreversible effects of this syndrome. While traditional cardiovascular therapy interventions, such as beta-blockers, have shown some positive results in preclinical and clinical research studies, recent preclinical studies have shown more successful results with certain non-traditional treatment options that have not been further evaluated yet. There is still no clinical standard of care or approved FDA drug to aid in the prevention or treatment of cancer-induced cardiac cachexia. This review aims to revisit the still not fully understood pathophysiological mechanisms of cancer-induced cardiac cachexia and explore recent studies using novel treatment strategies.

FUTURE DIRECTIONS

While research has progressed, further investigations might provide novel diagnostic techniques, potential biomarkers to monitor the progression of the disease, as well as viable pharmacological and non-pharmacological treatment options to increase quality of life and reduce cancer-induced cardiac cachexia-related mortality.

Regression of cardiac hypertrophy in health and disease: mechanisms and therapeutic potential

Left ventricular hypertrophy is a leading risk factor for cardiovascular morbidity and mortality. Although reverse ventricular remodelling was long thought to be irreversible, evidence from the past three decades indicates that this process is possible with many existing heart disease therapies. The regression of pathological hypertrophy is associated with improved cardiac function, quality of life and long-term health outcomes. However, less than 50% of patients respond favourably to most therapies, and the reversibility of remodelling is influenced by many factors, including age, sex, BMI and disease aetiology. Cardiac hypertrophy also occurs in physiological settings, including pregnancy and exercise, although in these cases, hypertrophy is associated with normal or improved ventricular function and is completely reversible postpartum or with cessation of training. Studies over the past decade have identified the molecular features of hypertrophy regression in health and disease settings, which include modulation of protein synthesis, microRNAs, metabolism and protein degradation pathways. In this Review, we summarize the evidence for hypertrophy regression in patients with current first-line pharmacological and surgical interventions. We further discuss the molecular features of reverse remodelling identified in cell and animal models, highlighting remaining knowledge gaps and the essential questions for future investigation towards the goal of designing specific therapies to promote regression of pathological hypertrophy.

Pathological features of tissues and cell populations during cancer cachexia

Cancers remain among the most devastating diseases in the human population in spite of considerable advances in limiting their impact on lifespan and healthspan. The multifactorial nature of cancers, as well as the number of tissues and organs that are affected, have exposed a considerable diversity in mechanistic features that are reflected in the wide array of therapeutic strategies that have been adopted. Cachexia is manifested in a number of diseases ranging from cancers to diabetes and ageing. In the context of cancers, a majority of patients experience cachexia and succumb to death due to the indirect effects of tumorigenesis that drain the energy reserves of different organs. Considerable information is available on the pathophysiological features of cancer cachexia, however limited knowledge has been acquired on the resident stem cell populations, and their function in the context of these diseases. Here we review current knowledge on cancer cachexia and focus on how tissues and their resident stem and progenitor cell populations are individually affected.

Cardioprotective effects of preconditioning exercise in the female tumor bearing mouse

Cancer cachexia, a metabolic wasting syndrome, affects up to 80% of cancer patients and leads to the death in up to 20% of cancer patients. While research is growing in the field, there are still no clear diagnostic criteria and cancer cachexia remains an untreated condition. Aerobic exercise has been shown to positively impact cachexia by slowing its development and attenuating muscle loss. The most effective timing, duration, and intensity of exercise as a preventative and protective measure against cancer cachexia remains questionable. Therefore, the purpose of this study was to examine the effects of preconditioning exercise as a protective measure for tumor-mediated muscle wasting. Female LC3 Tg+ and wildtype mice were randomly separated into four groups, sedentary non-tumor bearing (SED + NT), sedentary tumor bearing (SED + T), treadmill exercise non-tumor bearing (TM + NT), and treadmill exercise tumor bearing (TM + T). Mice underwent an 8-week treadmill exercise training protocol (TM) or remained sedentary (SED). Next, mice were implanted with tumor cells (T group; 5 × 105 Lewis Lung Carcinoma cells in flank) or remained non-tumor (NT) for 4 weeks. Tumor bearing resulted in a significant decline in cardiac function. SED + T showed a significant decrease in fractional shortening (p < 0.05) when compared to the other groups. This coincided with an increase in beclin-1 and MyD88 protein expression and decrease in p-FOXO1 (inactivated) protein expression in SED + T mice. Interestingly, preconditioning exercise (exercise prior to tumor bearing) appeared to preserve cardiac function (TM + T not significantly different than SED + NT). Exercise-mediated cardioprotection also coincided with abolished beclin-1 and MyD88 signaling that was not significantly elevated in TM + T mice. Additionally, TM resulted in a 22-fold decrease in estimated tumor volume (p < 0.05) and a 45% decrease in tumor mass (p < 0.05) compared to SED tumors. The data indicate potential cardioprotective effects of preconditioning exercise on preserving cardiac structure and function, as well as regulating autophagic (beclin-1), inflammatory (TGF-β and MyD88), and atrophy (p-FOXO1) pathways during tumor bearing. Preconditioning exercise may be an effective and accessible treatment intervention for early-stage cancer survivors. This data is crucial in identifying the significance of exercise and the timing of exercise as a protective measure against the detrimental effects of cancer cachexia.

Cardiac Remodeling in Cancer-Induced Cachexia: Functional, Structural, and Metabolic Contributors

Cancer cachexia is a syndrome of progressive weight loss and muscle wasting occurring in many advanced cancer patients. Cachexia significantly impairs quality of life and increases mortality. Cardiac atrophy and dysfunction have been observed in patients with cachexia, which may contribute to cachexia pathophysiology. However, relative to skeletal muscle, little research has been carried out to understand the mechanisms of cardiomyopathy in cachexia. Here, we review what is known clinically about the cardiac changes occurring in cachexia, followed by further discussion of underlying physiological and molecular mechanisms contributing to cachexia-induced cardiomyopathy. Impaired cardiac contractility and relaxation may be explained by a complex interplay of significant heart muscle atrophy and metabolic remodeling, including mitochondrial dysfunction. Because cardiac muscle has fundamental differences compared to skeletal muscle, understanding cardiac-specific effects of cachexia may bring light to unique therapeutic targets and ultimately improve clinical management for patients with cancer cachexia.

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.

Review of Mechanisms and Treatment of Cancer-Induced Cardiac Cachexia

Cancer cachexia is a multifactorial, paraneoplastic syndrome that impacts roughly half of all cancer patients. It can negatively impact patient quality of life and prognosis by causing physical impairment, reducing chemotherapy tolerance, and precluding them as surgical candidates. While there is substantial research on cancer-induced skeletal muscle cachexia, there are comparatively fewer studies and therapies regarding cardiac cachexia in the setting of malignancy. A literature review was performed using the PubMed database to identify original articles pertaining to cancer-induced cardiac cachexia, including its mechanisms and potential therapeutic modalities. Seventy studies were identified by two independent reviewers based on inclusion and exclusion criteria. While there are multiple studies addressing the pathophysiology of cardiac-induced cancer cachexia, there are no studies evaluating therapeutic options in the clinical setting. Many treatment modalities including nutrition, heart failure medication, cancer drugs, exercise, and gene therapy have been explored in in vitro and mice models with varying degrees of success. While these may be beneficial in cancer patients, further prospective studies specifically focusing on the assessment and treatment of the cardiac component of cachexia are needed.

Cardiac Complications: The Understudied Aspect of Cancer Cachexia

The global burden of cancer cachexia is increasing along with drastic increase in cancer patients. Cancer itself leads to cachexia, and cachexia development is associated with events like altered hemodynamics, and reduced functional capacity of the heart among others which lead to failure of the heart and are called cardiovascular complications associated with cancer cachexia. In some patients, the anti-cancer therapy also leads to this cardiovascular complications. So, in this review, an attempt is made to understand the mechanisms, pathophysiology of cardiovascular events in cachectic patients. Important processes which cause cardiovascular complications include alterations in the structure of the heart, loss of cardiac mass and functioning, cardiac fibrosis and cardiac remodeling, apoptosis, cardiac muscle atrophy, and mitochondrial alterations. Previously, the available treatment options were limited to nutraceuticals and physical exercise. Recently, studies with some prospective agents that can improve cardiac health have been reported, but whether their action is effective in cardiovascular complications associated with cancer cachexia is not known or are under trial.

Nutrition challenges of cancer cachexia

Cancer cachexia, or progressive weight loss, often despite adequate nutrition contributes greatly to cancer morbidity and mortality. Cachexia is metabolically distinct from starvation or protein malnutrition, although many patients with cancer and cachexia exhibit lowered appetite and food consumption. Tumors affect neural mechanisms that regulate appetite and energy expenditure, while promoting wasting of peripheral tissues via catabolism of cardiac and skeletal muscle, adipose, and bone. These multimodal actions of tumors on the host suggest a need for multimodal interventions. However, multiple recent consensus guidelines for management of cancer cachexia differ in treatment recommendations, highlighting the lack of effective, available therapies. Challenges to defining appropriate nutrition or other interventions for cancer cachexia include lack of consensus on definitions, low strength of evidence from clinical trials, and a scarcity of robust, rigorous, and mechanistic studies. However, efforts to diagnose, stage, and monitor cachexia are increasing along with clinical trial activity. Furthermore, preclinical models for cancer cachexia are growing more sophisticated, encompassing a greater number of tumor types in organ-appropriate contexts and for metastatic disease to model the clinical condition more accurately. It is expected that continued growth, investment, and coordination of research in this topic will ultimately yield robust biomarkers, clinically useful classification and staging algorithms, targetable pathways, pivotal clinical trials, and ultimately, cures. Here, we provide an overview of the clinical and scientific knowledge and its limitations around cancer cachexia.

Anthracycline-free tumor elimination in mice leads to functional and molecular cardiac recovery from cancer-induced alterations in contrast to long-lasting doxorubicin treatment effects

Systemic effects of advanced cancer impact on the heart leading to cardiac atrophy and functional impairment. Using a murine melanoma cancer model (B16F10 melanoma cells stably transduced with a Ganciclovir (GCV)-inducible suicide gene), the present study analysed the recovery potential of cancer-induced cardiomyopathy with or without use of doxorubicin (Dox). After Dox-free tumor elimination and recovery for 70 ± 5 days, cancer-induced morphologic, functional, metabolic and molecular changes were largely reversible in mice previously bearing tumors. Moreover, grip strength and cardiac response to angiotensin II-induced high blood pressure were comparable with healthy control mice. In turn, addition of Dox (12 mg/kg BW) to melanoma-bearing mice reduced survival in the acute phase compared to GCV-alone induced recovery, while long-term effects on cardiac morphologic and functional recovery were similar. However, Dox treatment was associated with permanent changes in the cardiac gene expression pattern, especially the circadian rhythm pathway associated with the DNA damage repair system. Thus, the heart can recover from cancer-induced damage after chemotherapy-free tumor elimination. In contrast, treatment with the cardiotoxic drug Dox induces, besides well-known adverse acute effects, long-term subclinical changes in the heart, especially of circadian clock genes. Since the circadian clock is known to impact on cardiac repair mechanisms, these changes may render the heart more sensitive to additional stress during lifetime, which, at least in part, could contribute to late cardiac toxicity.

The Role of Autophagy Modulated by Exercise in Cancer Cachexia

Cancer cachexia is a syndrome experienced by many patients with cancer. Exercise can act as an autophagy modulator, and thus holds the potential to be used to treat cancer cachexia. Autophagy imbalance plays an important role in cancer cachexia, and is correlated to skeletal and cardiac muscle atrophy and energy-wasting in the liver. The molecular mechanism of autophagy modulation in different types of exercise has not yet been clearly defined. This review aims to elaborate on the role of exercise in modulating autophagy in cancer cachexia. We evaluated nine studies in the literature and found a potential correlation between the type of exercise and autophagy modulation. Combined exercise or aerobic exercise alone seems more beneficial than resistance exercise alone in cancer cachexia. Looking ahead, determining the physiological role of autophagy modulated by exercise will support the development of a new medical approach for treating cancer cachexia. In addition, the harmonization of the exercise type, intensity, and duration might play a key role in optimizing the autophagy levels to preserve muscle function and regulate energy utilization in the liver.

Cancer cachexia: molecular mechanism and pharmacological management

Cancer cachexia often occurs in malignant tumors and is a multifactorial and complex symptom characterized by wasting of skeletal muscle and adipose tissue, resulting in weight loss, poor life quality and shorter survival. The pathogenic mechanism of cancer cachexia is complex, involving a variety of molecular substrates and signal pathways. Advancements in understanding the molecular mechanisms of cancer cachexia have provided a platform for the development of new targeted therapies. Although recent outcomes of early-phase trials have showed that several drugs presented an ideal curative effect, monotherapy cannot be entirely satisfactory in the treatment of cachexia-associated symptoms due to its complex and multifactorial pathogenesis. Therefore, the lack of definitive therapeutic strategies for cancer cachexia emphasizes the need to develop a better understanding of the underlying mechanisms. Increasing evidences show that the progression of cachexia is associated with metabolic alternations, which mainly include excessive energy expenditure, increased proteolysis and mitochondrial dysfunction. In this review, we provided an overview of the key mechanisms of cancer cachexia, with a major focus on muscle atrophy, adipose tissue wasting, anorexia and fatigue and updated the latest progress of pharmacological management of cancer cachexia, thereby further advancing the interventions that can counteract cancer cachexia.

The Role of Tumor Microenvironment Cells in Colorectal Cancer (CRC) Cachexia

Cancer cachexia (CC) is a multifactorial syndrome in patients with advanced cancer characterized by weight loss via skeletal-muscle and adipose-tissue atrophy, catabolic activity, and systemic inflammation. CC is correlated with functional impairment, reduced therapeutic responsiveness, and poor prognosis, and is a major cause of death in cancer patients. In colorectal cancer (CRC), cachexia affects around 50–61% of patients, but remains overlooked, understudied, and uncured. The mechanisms driving CC are not fully understood but are related, at least in part, to the local and systemic immune response to the tumor. Accumulating evidence demonstrates a significant role of tumor microenvironment (TME) cells (e.g., macrophages, neutrophils, and fibroblasts) in both cancer progression and tumor-induced cachexia, through the production of multiple procachectic factors. The most important role in CRC-associated cachexia is played by pro-inflammatory cytokines, including the tumor necrosis factor α (TNFα), originally known as cachectin, Interleukin (IL)-1, IL-6, and certain chemokines (e.g., IL-8). Heterogeneous CRC cells themselves also produce numerous cytokines (including chemokines), as well as novel factors called “cachexokines”. The tumor microenvironment (TME) contributes to systemic inflammation and increased oxidative stress and fibrosis. This review summarizes the current knowledge on the role of TME cellular components in CRC-associated cachexia, as well as discusses the potential role of selected mediators secreted by colorectal cancer cells in cooperation with tumor-associated immune and non-immune cells of tumor microenvironment in inducing or potentiating cancer cachexia. This knowledge serves to aid the understanding of the mechanisms of this process, as well as prevent its consequences.

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.

Cancer-induced Cardiac Atrophy Adversely Affects Myocardial Redox State and Mitochondrial Oxidative Characteristics

Cachexia presents in 80% of advanced cancer patients; however, cardiac atrophy in cachectic patients receives little attention. This cardiomyopathy contributes to increased occurrence of adverse cardiac events compared to age-matched population norms. Research on cardiac atrophy has focused on remodeling; however, alterations in metabolic properties may be a primary contributor.

PURPOSE

Determine how cancer-induced cardiac atrophy alters mitochondrial turnover, mitochondrial mRNA translation machinery and in-vitro oxidative characteristics.

METHODS

Lewis lung carcinoma (LLC) tumors were implanted in C57BL6/J mice and grown for 28days to induce cardiac atrophy. Endogenous metabolic species, and markers of mitochondrial function were assessed. H9c2 cardiomyocytes were cultured in LLC-conditioned media with(out) the antioxidant MitoTempo. Cells were analyzed for ROS, oxidative capacity, and hypoxic resistance.

RESULTS

LLC heart weights were ~10% lower than controls. LLC hearts demonstrated ~15% lower optical redox ratio (FAD/FAD+NADH) compared to PBS controls. When compared to PBS, LLC hearts showed ~50% greater COX-IV and VDAC, attributed to ~50% lower mitophagy markers. mt-mRNA translation machinery was elevated similarly to markers of mitochondrial content. mitochondrial DNA-encoded Cytb was ~30% lower in LLC hearts. ROS scavengers GPx-3 and GPx-7 were ~50% lower in LLC hearts. Treatment of cardiomyocytes with LLC-conditioned media resulted in higher ROS (25%), lower oxygen consumption rates (10% at basal, 75% at maximal), and greater susceptibility to hypoxia (~25%) -- which was reversed by MitoTempo.

CONCLUSION

These results substantiate metabolic cardiotoxic effects attributable to tumor-associated factors and provide insight into interactions between mitochondrial mRNA translation, ROS mitigation, oxidative capacity and hypoxia resistance.

ACVR2B antagonism as a countermeasure to multi-organ perturbations in metastatic colorectal cancer cachexia

BACKGROUND

Advanced colorectal cancer (CRC) is often accompanied by the development of liver metastases, as well as cachexia, a multi-organ co-morbidity primarily affecting skeletal (SKM) and cardiac muscles. Activin receptor type 2B (ACVR2B) signalling is known to cause SKM wasting, and its inhibition restores SKM mass and prolongs survival in cancer. Using a recently generated mouse model, here we tested whether ACVR2B blockade could preserve multiple organs, including skeletal and cardiac muscle, in the presence of metastatic CRC.

METHODS

NSG male mice (8 weeks old) were injected intrasplenically with HCT116 human CRC cells (mHCT116), while sham-operated animals received saline (n = 5-10 per group). Sham and tumour-bearing mice received weekly injections of ACVR2B/Fc, a synthetic peptide inhibitor of ACVR2B.

RESULTS

mHCT116 hosts displayed losses in fat mass ( - 79%, P < 0.0001), bone mass ( - 39%, P < 0.05), and SKM mass (quadriceps: - 22%, P < 0.001), in line with reduced muscle cross-sectional area ( - 24%, P < 0.01) and plantarflexion force ( - 28%, P < 0.05). Further, despite only moderately affected heart size, cardiac function was significantly impaired (ejection fraction %: - 16%, P < 0.0001; fractional shortening %: - 25%, P < 0.0001) in the mHCT116 hosts. Conversely, ACVR2B/Fc preserved fat mass ( + 238%, P < 0.001), bone mass ( + 124%, P < 0.0001), SKM mass (quadriceps: + 31%, P < 0.0001), size (cross-sectional area: + 43%, P < 0.0001) and plantarflexion force ( + 28%, P < 0.05) in tumour hosts. Cardiac function was also completely preserved in tumour hosts receiving ACVR2B/Fc (ejection fraction %: + 19%, P < 0.0001), despite no effect on heart size. RNA sequencing analysis of heart muscle revealed rescue of genes related to cardiac development and contraction in tumour hosts treated with ACVR2B/Fc.

CONCLUSIONS

Our metastatic CRC model recapitulates the multi-systemic derangements of cachexia by displaying loss of fat, bone, and SKM along with decreased muscle strength in mHCT116 hosts. Additionally, with evidence of severe cardiac dysfunction, our data support the development of cardiac cachexia in the occurrence of metastatic CRC. Notably, ACVR2B antagonism preserved adipose tissue, bone, and SKM, whereas muscle and cardiac functions were completely maintained upon treatment. Altogether, our observations implicate ACVR2B signalling in the development of multi-organ perturbations in metastatic CRC and further dictate that ACVR2B represents a promising therapeutic target to preserve body composition and functionality in cancer cachexia.

Diverging metabolic programmes and behaviours during states of starvation, protein malnutrition, and cachexia

BACKGROUND

Our evolutionary history is defined, in part, by our ability to survive times of nutrient scarcity. The outcomes of the metabolic and behavioural adaptations during starvation are highly efficient macronutrient allocation, minimization of energy expenditure, and maximized odds of finding food. However, in different contexts, caloric deprivation is met with vastly different physiologic and behavioural responses, which challenge the primacy of energy homeostasis.

METHODS

We conducted a literature review of scientific studies in humans, laboratory animals, and non-laboratory animals that evaluated the physiologic, metabolic, and behavioural responses to fasting, starvation, protein-deficient or essential amino acid-deficient diets, and cachexia. Studies that investigated the changes in ingestive behaviour, locomotor activity, resting metabolic rate, and tissue catabolism were selected as the focus of discussion.

RESULTS

Whereas starvation responses prioritize energy balance, both protein malnutrition and cachexia present existential threats that induce unique adaptive programmes, which can exacerbate the caloric insufficiency of undernutrition. We compare and contrast the behavioural and metabolic responses and elucidate the mechanistic pathways that drive state-dependent alterations in energy seeking and partitioning.

CONCLUSIONS

The evolution of energetically inefficient metabolic and behavioural responses to protein malnutrition and cachexia reveal a hierarchy of metabolic priorities governed by discrete regulatory networks.

Development and progression of cancer cachexia: Perspectives from bench to bedside

Cancer cachexia (CC) is a devastating syndrome characterized by weight loss, reduced fat mass and muscle mass that affects approximately 80% of cancer patients and is responsible for 22%-30% of cancer-associated deaths. Understanding underlying mechanisms for the development of CC are crucial to advance therapies to treat CC and improve cancer outcomes. CC is a multi-organ syndrome that results in extensive skeletal muscle and adipose tissue wasting; however, CC can impair other organs such as the liver, heart, brain, and bone as well. A considerable amount of CC research focuses on changes that occur within the muscle, but cancer-related impairments in other organ systems are understudied. Furthermore, metabolic changes in organ systems other than muscle may contribute to CC. Therefore, the purpose of this review is to address degenerative mechanisms which occur during CC from a whole-body perspective. Outlining the information known about metabolic changes that occur in response to cancer is necessary to develop and enhance therapies to treat CC. As much of the current evidences in CC are from pre-clinical models we should note the majority of the data reviewed here are from preclinical models.

Pirfenidone and Vitamin D Ameliorate Cardiac Fibrosis Induced by Doxorubicin in Ehrlich Ascites Carcinoma Bearing Mice: Modulation of Monocyte Chemoattractant Protein-1 and Jun N-terminal Kinase-1 Pathways

Treatment of breast cancer with doxorubicin causes numerous side effects, of which cardiac fibrosis is considered the main one. This study was designed to investigate the underlying molecular mechanisms for the potential anti-fibrotic effect of pirfenidone and vitamin D against doxorubicin-induced cardiac fibrosis. Seventy mice carrying solid Ehrlich’s ascites carcinoma (EAC) discs on the ventral side were treated with orally administered pirfenidone (500 mg/kg) and intraperitoneal injection of vitamin D (0.5 µg/kg) either individually or in combination with a doxorubicin (15 mg/kg; i.p.) single dose. All treatments commenced one week post-tumor inoculation and continued for 14 days. Compared to control EAC mice, the doxorubicin group showed a significant increase in heart and left ventricle weights, troponin T, and creatinine kinase serum levels. Furthermore, the doxorubicin group depicts a high expression of monocyte chemoattractant protein (MCP-1), nuclear factor-kappa B (NF-κB), transforming growth factor-beta 1 (TGF-β1), smad3, Jun N-terminal Kinase-1 (JNK1), and alpha-smooth muscle actin (α-SMA). Treatment with pirfenidone or vitamin D significantly decreased all of these parameters. Furthermore, the expression of smad7 was downregulated by doxorubicin and improved by pirfenidone or vitamin D. Furthermore, all treated groups showed a marked decrease in tumor weight and volume. Current data demonstrate that pirfenidone and vitamin D represent an attractive approach to ameliorate the cardiac fibrosis produced by doxorubicin through inhibiting both JNK1 signaling and MCP-1 inflammatory pathways, thus preserving heart function. Further, this combination demonstrated an anti-tumor effect to combat breast cancer.

Molecular mechanisms of cancer cachexia‑induced muscle atrophy (Review)

Muscle atrophy is a severe clinical problem involving the loss of muscle mass and strength that frequently accompanies the development of numerous types of cancer, including pancreatic, lung and gastric cancers. Cancer cachexia is a multifactorial syndrome characterized by a continuous decline in skeletal muscle mass that cannot be reversed by conventional nutritional therapy. The pathophysiological characteristic of cancer cachexia is a negative protein and energy balance caused by a combination of factors, including reduced food intake and metabolic abnormalities. Numerous necessary cellular processes are disrupted by the presence of abnormal metabolites, which mediate several intracellular signaling pathways and result in the net loss of cytoplasm and organelles in atrophic skeletal muscle during various states of cancer cachexia. Currently, the clinical morbidity and mortality rates of patients with cancer cachexia are high. Once a patient enters the cachexia phase, the consequences are difficult to reverse and the treatment methods for cancer cachexia are very limited. The present review aimed to summarize the recent discoveries regarding the pathogenesis of cancer cachexia-induced muscle atrophy and provided novel ideas for the comprehensive treatment to improve the prognosis of affected patients.

Withaferin A attenuates ovarian cancer-induced cardiac cachexia

Cachexia is a common multifactorial syndrome in the advanced stages of cancer and accounts for approximately 20–30% of all cancer-related fatalities. In addition to the progressive loss of skeletal muscle mass, cancer results in impairments in cardiac function. We recently demonstrated that WFA attenuates the cachectic skeletal muscle phenotype induced by ovarian cancer. The purpose of this study was to investigate whether ovarian cancer induces cardiac cachexia, the possible pathway involved, and whether WFA attenuates cardiac cachexia. Xenografting of ovarian cancer induced cardiac cachexia, leading to the loss of normal heart functions. Treatment with WFA rescued the heart weight. Further, ovarian cancer induced systolic dysfunction and diastolic dysfunction Treatment with WFA preserved systolic function in tumor-bearing mice, but diastolic dysfunction was partially improved. In addition, WFA abrogated the ovarian cancer-induced reduction in cardiomyocyte cross-sectional area. Finally, treatment with WFA ameliorated fibrotic deposition in the hearts of tumor-bearing animals. We observed a tumor-induced MHC isoform switching from the adult MHCα to the embryonic MHCβ isoform, which was prevented by WFA treatment. Circulating Ang II level was increased significantly in the tumor-bearing, which was lowered by WFA treatment. Our results clearly demonstrated the induction of cardiac cachexia in response to ovarian tumors in female NSG mice. Further, we observed induction of proinflammatory markers through the AT₁R pathway, which was ameliorated by WFA, in addition to amelioration of the cachectic phenotype, suggesting WFA as a potential therapeutic agent for cardiac cachexia in oncological paradigms.

High Density Lipoprotein and Its Precursor Protein Apolipoprotein A1 as Potential Therapeutics to Prevent Anthracycline Associated Cardiotoxicity

Cardiovascular disease and cancer are the leading causes of death in developed societies. Despite their effectiveness, many cancer therapies exhibit deleterious cardiovascular side effects such as cardiotoxicity and heart failure. The cardiotoxic effects of anthracyclines such as doxorubicin are the most well-characterized of cardiotoxic anti-cancer therapies. While other anti-neoplastic drugs also induce cardiotoxicity, often leading to heart failure, they are beyond the scope of this review. This review first summarizes the mechanisms of doxorubicin-induced cardiotoxicity. It then reviews emerging preclinical evidence that high density lipoprotein and its precursor protein apolipoprotein A1, which are known for their protective effects against ischemic cardiovascular disease, may also protect against doxorubicin-induced cardiotoxicity both directly and indirectly, when used therapeutically.

Advances in cancer cachexia: Intersection between affected organs, mediators, and pharmacological interventions

Advanced cancer patients exhibit cachexia, a condition characterized by a significant reduction in the body weight predominantly from loss of skeletal muscle and adipose tissue. Cachexia is one of the major causes of morbidity and mortality in cancer patients. Decreased food intake and multi-organ energy imbalance in cancer patients worsen the cachexia syndrome. Cachectic cancer patients have a low tolerance for chemo- and radiation therapies and also have a reduced quality of life. The presence of tumors and the current treatment options for cancer further exacerbate the cachexia condition, which remains an unmet medical need. The onset of cachexia involves crosstalk between different organs leading to muscle wasting. Recent advancements in understanding the molecular mechanisms of skeletal muscle atrophy/hypertrophy and adipose tissue wasting/browning provide a platform for the development of new targeted therapies. Therefore, a better understanding of this multifactorial disorder will help to improve the quality of life of cachectic patients. In this review, we summarize the metabolic mediators of cachexia, their molecular functions, affected organs especially with respect to muscle atrophy and adipose browning and then discuss advanced therapeutic approaches to cancer cachexia.

[Pathogenetic mechanisms of development of myocardial pathology in patients with malignant tumors: the current state of the problem]

The myocardium, which has a high metabolic activity, responds to metabolic disorders and energy imbalance induced by a growing malignant tumor. In addition, the tumor itself can produce substances that directly affect metabolic processes and the life cycle of cells not involved in the neoplastic process, including cardiomyocytes. This review summarized and systematized current data on individual aspects of detrimental effects of oncogenes and tumor-related factors on the heart muscle and morpho-functional changes in the cardiovascular system of oncology patients. Also, the authors described in detail development of these pathogenetic mechanisms.

Impaired cardiac performance, protein synthesis, and mitochondrial function in tumor-bearing mice

Background

To understand the underlying mechanisms of cardiac dysfunction in cancer, we examined cardiac function, protein synthesis, mitochondrial function and gene expression in a model of heart failure in mice injected with Lewis lung carcinoma (LLC1) cells.

Experimental design

Seven week-old C57BL/J6 male and female mice were injected with LLC1 cells or vehicle. Cardiac ejection fraction, ventricular wall and septal thickness were reduced in male, but not female, tumor-bearing mice compared to vehicle-injected control mice. Cardiac protein synthesis was reduced in tumor-bearing male mice compared to control mice (p = 0.025). Aspect ratio and form factor of cardiac mitochondria from the tumor-bearing mice were increased compared control mice (p = 0.042 and p = 0.0032, respectively) indicating a more fused mitochondrial network in the hearts of tumor-bearing mice. In cultured cardiomyocytes maximal oxygen consumption and mitochondrial reserve capacity were reduced in cells exposed to tumor cell-conditioned medium compared to non-conditioned medium (p = 0.0059, p = 0.0010). Whole transcriptome sequencing of cardiac ventricular muscle from tumor-bearing vs. control mice showed altered expression of 1648 RNA transcripts with a false discovery rate of less than 0.05. Of these, 54 RNA transcripts were reduced ≤ 0.5 fold, and 3 RNA transcripts were increased by ≥1.5-fold in tumor-bearing mouse heart compared to control. Notably, the expression of mRNAs for apelin (Apln), the apelin receptor (Aplnr), the N-myc proto-oncogene, early growth protein (Egr1), and the transcription factor Sox9 were reduced by >50%, whereas the mRNA for growth arrest and DNA-damage-inducible, beta (Gadd45b) is increased >2-fold, in ventricular tissue from tumor-bearing mice compared to control mice.

Conclusions

Lung tumor cells induce heart failure in male mice in association with reduced protein synthesis, mitochondrial function, and the expression of the mRNAs for inotropic and growth factors. These data provide new mechanistic insights into cancer-associated heart failure that may help unlock treatment options for this condition.

Modulation of cardiac AKT and STAT3 signalling in preclinical cancer models and their impact on the heart

BACKGROUND

Advanced cancer induces fundamental cardiac changes and promotes body wasting and heart failure. We evaluated the impact of cancer on major cardiac signalling pathways, and resulting consequences for the heart.

METHODS AND RESULTS

Metastatic melanoma disease was induced in male C57BL/6 N mice by intraperitoneal injection of the melanoma cell line B16F10 and lead to cardiac atrophy and heart failure. Analyses of key cardiac signalling pathways in left ventricular tissue revealed increased activation of STAT3 and reduced activation of AKT, p38 and ERK1/2. Markers of the ubiquitin proteasomal system (UPS: Atrogin-1) and of mitophagy/autophagy (LC3b, BNIP3) were upregulated. Tumour-bearing C57BL/6 N mice with a cardiomyocyte-specific overexpression of a constitutively active AKT transgene (AKTtg) displayed less cardiac atrophy and dysfunction and normalized Atrogin-1, LC3b and BNIP3 expression while the cardiomyocyte-specific knockout of STAT3 (CKO) had no major effect on these parameters compared to WT.

CONCLUSION

Cancer alters major cardiac signalling pathways and subsequently the UPS, mitophagy and autophagy. The present study suggests that cancer-induced reduction of cardiomyocyte AKT contributes to these alterations as they were attenuated in tumour-bearing AKTtg mice. In turn, increased cardiomyocyte STAT3 activation appears less relevant, as tumour-induced impairment on the heart was largely similar in CKO and WT mice. Since oncologic therapies frequently target AKT and/or STAT3, their impact on the heart might be different in tumour-bearing mice compared to healthy mice, a feature suggesting to test tumour therapies also in tumour disease models and not only under healthy conditions. This article is part of a Special Issue entitled: Cardiomyocyte biology: new pathways of differentiation and regeneration edited by Marijke Brink, Marcus C. Schaub, and Christian Zuppinger.

Mitophagy in Cancer: A Tale of Adaptation

：In the past years, we have learnt that tumors co-evolve with their microenvironment, and that the active interaction between cancer cells and stromal cells plays a pivotal role in cancer initiation, progression and treatment response. Among the players involved, the pathways regulating mitochondrial functions have been shown to be crucial for both cancer and stromal cells. This is perhaps not surprising, considering that mitochondria in both cancerous and non-cancerous cells are decisive for vital metabolic and bioenergetic functions and to elicit cell death. The central part played by mitochondria also implies the existence of stringent mitochondrial quality control mechanisms, where a specialized autophagy pathway (mitophagy) ensures the selective removal of damaged or dysfunctional mitochondria. Although the molecular underpinnings of mitophagy regulation in mammalian cells remain incomplete, it is becoming clear that mitophagy pathways are intricately linked to the metabolic rewiring of cancer cells to support the high bioenergetic demand of the tumor. In this review, after a brief introduction of the main mitophagy regulators operating in mammalian cells, we discuss emerging cell autonomous roles of mitochondria quality control in cancer onset and progression. We also discuss the relevance of mitophagy in the cellular crosstalk with the tumor microenvironment and in anti-cancer therapy responses.

mTOR and Tumor Cachexia

Cancer cachexia affects most patients with advanced forms of cancers. It is mainly characterized by weight loss, due to muscle and adipose mass depletion. As cachexia is associated with increased morbidity and mortality in cancer patients, identifying the underlying mechanisms leading to cachexia is essential in order to design novel therapeutic strategies. The mechanistic target of rapamycin (mTOR) is a major intracellular signalling intermediary that participates in cell growth by upregulating anabolic processes such as protein and lipid synthesis. Accordingly, emerging evidence suggests that mTOR and mTOR inhibitors influence cancer cachexia. Here, we review the role of mTOR in cellular processes involved in cancer cachexia and highlight the studies supporting the contribution of mTOR in cancer cachexia.

Subcutaneous Ehrlich Ascites Carcinoma mice model for studying cancer-induced cardiomyopathy

Cardiomyopathy is one of the characteristic features of cancer. In this study, we establish a suitable model to study breast cancer-induced cardiomyopathy in mice. We used Ehrlich Ascites Carcinoma cells to induce subcutaneous tumor in 129/SvJ mice and studied its effect on heart function. In Ehrlich Ascites Carcinoma bearing mice, we found significant reduction in left ventricle wall thickness, ejection fraction, and fractional shortening increase in left ventricle internal diameter. We found higher muscle atrophy, degeneration, fibrosis, expression of cell-adhesion molecules and cell death in tumor-bearing mice hearts. As observed in cancer patients, we found that mTOR, a key signalling molecule responsible for maintaining cell growth and autophagy was suppressed in this model. Tumor bearing mice hearts show increased expression and nuclear localization of TFEB and FoxO3a transcription factors, which are involved in the upregulation of muscle atrophy genes, lysosomal biogenesis genes and autophagy genes. We propose that Ehrlich Ascites Carcinoma induced tumor can be used as a model to identify potential therapeutic targets for the treatment of heart failure in patients suffering from cancer-induced cardiomyopathy. This model can also be used to test the adverse consequences of cancer chemotherapy in heart.

Cancer-induced cardiac cachexia: Pathogenesis and impact of physical activity (Review)

Cachexia is a wasting syndrome observed in many patients suffering from several chronic diseases including cancer. In addition to the progressive loss of skeletal muscle mass, cancer cachexia results in cardiac function impairment. During the severe stage of the disease, patients as well as animals bearing cancer cells display cardiac atrophy. Cardiac energy metabolism is also impeded with disruption of mitochondrial homeostasis and reduced oxidative capacity, although the available data remain equivocal. The release of inflammatory cytokines by tumor is a key mechanism in the initiation of heart failure. Oxidative stress, which results from the combination of chemotherapy, inadequate antioxidant consumption and chronic inflammation, will further foster heart failure. Protein catabolism is due to the concomitant activation of proteolytic systems and inhibition of protein synthesis, both processes being triggered by the deactivation of the Akt/mammalian target of rapamycin pathway. The reduction in oxidative capacity involves AMP-activated protein kinase and peroxisome proliferator-activated receptor gamma coactivator 1α dysregulation. The nuclear factor-κB transcription factor plays a prominent role in the coordination of these alterations. Physical exercise appears as an interesting non-pharmaceutical way to counteract cancer cachexia-induced-heart failure. Indeed, aerobic training has anti-inflammatory effects, increases anti-oxidant defenses, prevents atrophy and promotes oxidative metabolism. The present review points out the importance of better understanding the concurrent structural and metabolic changes within the myocardium during cancer and the protective effects of exercise against cardiac cachexia.

Predictive value of the modified Glasgow Prognostic Score for the therapeutic effects of molecular-targeted drugs on advanced renal cell carcinoma

Inflammation is considered to be a prognostic factor for renal cell carcinoma (RCC). An inflammation-based prognostic score (modified Glasgow Prognostic Score; mGPS) is widely used for preoperative patients; however, little information is available regarding its prognostic value in patients with RCC treated with molecular-targeted drugs. A total of 32 advanced and recurrent RCC patients initially treated with molecular-targeted drugs from October, 2009 to August, 2015 were retrospectively investigated. Information on patient characteristics prior to treatment initiation and the clinical course were retrieved from clinical records. The correlation between survival and patient variables was analyzed. Survival was compared among patient groups according to the mGPS score. The median patient age was 66 years. The percentage of patients with an Eastern Cooperative Oncology Group performance status of 0 or 1 was 87.5, and 65.6% of the RCCs were clear cell carcinomas. A Memorial Sloan-Kettering Cancer Center index of good or intermediate was determined for 75% of the patients. Sunitinib, pazopanib or sorafenib was administered to 56, 22 and 13% of the cases, respectively. An mGPS score of 0, 1 and 2 was calculated for 66, 9 and 25% of the cases, respectively. Patients in the mGPS low group (score 0) exhibited significantly better progression-free survival (PFS) and overall survival (OS) compared with patients in the mGPS high group (score 1 or 2) (median PFS, 307 vs. 70 days and median OS, 1,081 vs. 140 days, respectively). In conclusion, inflammatory status as assessed by the mGPS score was closely associated with the prognosis of RCC patients treated with molecular-targeted therapy.

Cardiac Atrophy and Heart Failure In Cancer

Functional changes in the heart in patients with cancer can be a result of both the disease itself and various cancer therapies, and limiting cardiac damage has become an increasingly important issue as survival rates in patients with cancer have improved. Processes involved in cancer-induced cardiac atrophy may include cardiomyocyte atrophy and apoptosis, decreased protein synthesis, increased autophagy and proteolysis via the ubiquitin-proteosome system. Further to direct effects of malignancy on the heart, several chemotherapeutic agents are known to affect the myocardium, in particular the anthracyclines. The aim of this report is to review the effects of cancer and cancer treatment on the heart and what is known about the underlying mechanisms. Furthermore, clinical strategies to limit and treat cancer-associated cardiac atrophy are discussed, emphasising the benefit of a multidisciplinary approach by cardiologists and oncologists to optimise models of care to improve outcomes for patients with cancer.

Megestrol acetate improves cardiac function in a model of cancer cachexia-induced cardiomyopathy by autophagic modulation

BACKGROUND

Cachexia is a complex metabolic syndrome associated with cancer. One of the features of cachexia is the loss of muscle mass, characterized by an imbalance between protein synthesis and protein degradation. Muscle atrophy is caused by the hyperactivation of some of the main cellular catabolic pathways, including autophagy. Cachexia also affects the cardiac muscle. As a consequence of the atrophy of the heart, cardiac function is impaired and mortality is increased. Anti-cachectic therapy in patients with cancer cachexia is so far limited to nutritional support and anabolic steroids. The use of the appetite stimulant megestrol acetate (MA) has been discussed as a treatment for cachexia.

METHODS

In this study the effects of MA were tested in cachectic tumour-bearing rats (Yoshida AH-130 ascites hepatoma). Rats were treated daily with 100 mg/kg of MA or placebo starting one day after tumour inoculation, and for a period of 16 days. Body weight and body composition were assessed at baseline and at the end of the study. Cardiac function was analysed by echocardiography at baseline and at day 11. Locomotor activity and food intake were assessed before tumour inoculation and at day 11. Autophagic markers were assessed in gastrocnemius muscle and heart by western blot analysis.

RESULTS

Treatment with 100 mg/kg/day MA significantly attenuated the loss of body weight (-9 ± 12%, P < 0.05) and the wasting of lean and fat mass (-7.0 ± 6% and -22.4 ± 3 %, P < 0.001 and P < 0.05, respectively). Administration of 100 mg/kg/day MA significantly protected the heart from general atrophy (633.8 ± 30 mg vs. placebo 474 ± 13 mg, P < 0.001). Tumour-bearing rats displayed cardiac dysfunction, as indicated by the significant impairment of the left ventricular ejection fraction, the left ventricular fractional shortening, the stroke volume, the end dyastolic volume, and the end systolic volume. In contrast, MA significantly improved left ventricular ejection fraction, left ventricular fractional shortening, and left ventricular end systolic volume. Western blotting analysis showed an upregulation of the autophagic pathway in the gastrocnemius and hearts of the placebo-treated tumour-bearing rats. Treatment with MA, however, was able to modulate the autophagic markers (e.g. Beclin-1, p62, TRAF6, and LC3) in the gastrocnemius and in the hearts of tumour-bearing rats. Most importantly, 100 mg/kg/day MA reduced mortality [hazard ratio (HR): 0.44; 95%CI: 0.20-1.00; P = 0.0486].

CONCLUSIONS

Megestrol acetate improved survival and reduced wasting through a marked downregulation of autophagy, occurring in both skeletal and heart muscle, the latter effect leading to a significant improvement of cardiac function. Our data suggest that MA might represent a valuable strategy to counteract the development of cancer cachexia-induced cardiomyopathy.

Pay attention to cardiac remodeling in cancer cachexia

Cancer cachexia is a complex and multifaceted disease state characterized by fatigue, weakness, and loss of skeletal muscle and adipose tissue. Recently, the profound negative effects of cancer cachexia on cardiac tissue draw much attention, which is likely to contribute to mortality in tumor-bearing animals. The mechanism of cardiac remodeling is not so clear and involved with a series of molecular alterations. In cancer cachexia model, progressive loss of left ventricular mass and decrease in myocardial function is observed and cardiac autonomic functions are altered. Levels of several emerging cardiovascular neurohormones are found elevating in patients with cancer, but it is still controversial whether the changes could reflect the heart injury accurately. The remedy for cardiac remodeling has been explored. It is showed that exercise can modulate signaling pathways activated by wasting cytokines and impact on the resulting outcomes on heart adaptation. Some drugs, such as bisoprolol, spironolactone, perindopril, tandospirone, and simvastatin, can mitigate adverse effects of the tumor on the heart and prolong survival.

The pathogenesis and treatment of cardiac atrophy in cancer cachexia

Cancer cachexia is a multifactorial syndrome characterized by a progressive loss of skeletal muscle mass associated with significant functional impairment. In addition to a loss of skeletal muscle mass and function, many patients with cancer cachexia also experience cardiac atrophy, remodeling, and dysfunction, which in the field of cancer cachexia is described as cardiac cachexia. The cardiac alterations may be due to underlying heart disease, the cancer itself, or problems initiated by the cancer treatment and, unfortunately, remains largely underappreciated by clinicians and basic scientists. Despite recent major advances in the treatment of cancer, little progress has been made in the treatment of cardiac cachexia in cancer, and much of this is due to lack of information regarding the mechanisms. This review focuses on the cardiac atrophy associated with cancer cachexia, describing some of the known mechanisms and discussing the current and future therapeutic strategies to treat this condition. Above all else, improved awareness of the condition and an increased focus on identification of mechanisms and therapeutic targets will facilitate the eventual development of an effective treatment for cardiac atrophy in cancer cachexia.

Ataxin-10 is part of a cachexokine cocktail triggering cardiac metabolic dysfunction in cancer cachexia

Objectives

Cancer cachexia affects the majority of tumor patients and significantly contributes to high mortality rates in these subjects. Despite its clinical importance, the identity of tumor-borne signals and their impact on specific peripheral organ systems, particularly the heart, remain mostly unknown.

Methods and results

By combining differential colon cancer cell secretome profiling with large-scale cardiomyocyte phenotyping, we identified a signature panel of seven “cachexokines”, including Bridging integrator 1, Syntaxin 7, Multiple inositol-polyphosphate phosphatase 1, Glucosidase alpha acid, Chemokine ligand 2, Adamts like 4, and Ataxin-10, which were both sufficient and necessary to trigger cardiac atrophy and aberrant fatty acid metabolism in cardiomyocytes. As a prototypical example, engineered secretion of Ataxin-10 from non-cachexia-inducing cells was sufficient to induce cachexia phenotypes in cardiomyocytes, correlating with elevated Ataxin-10 serum levels in murine and human cancer cachexia models.

Conclusions

As Ataxin-10 serum levels were also found to be elevated in human cachectic cancer patients, the identification of Ataxin-10 as part of a cachexokine cocktail now provides a rational approach towards personalized predictive, diagnostic and therapeutic measures in cancer cachexia.

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Cancer cachexia induces remodeling of the heart.

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Tumor-borne secreted factors mediate cardiomyocyte atrophy.

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Selective cachexokines, including Bin1, Stx7, Minpp1, Gaa, Ccl2, Adamtsl4, and Atxn10 provoke aberrant cardiac FA metabolism.

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Ataxin-10 levels are elevated under cachectic conditions in mice and tumor patients.

Cerium oxide nanoparticles attenuate acute kidney injury induced by intra-abdominal infection in Sprague-Dawley rats

Background

Intra-abdominal infection or peritonitis is a cause for great concern due to high mortality rates. The prognosis of severe intra-abdominal infection is significantly diminished in the presence of acute kidney injury (AKI) which is often characterized by renal tubular cell death that can lead to renal failure. The purpose of the current study is to examine the therapeutic efficacy of cerium oxide (CeO₂) nanoparticles for the treatment of peritonitis-induced AKI by polymicrobial insult.

Results

A one-time administration of CeO₂ nanoparticles (0.5 mg/kg) in the absence of antibiotics or other supportive care, attenuated peritonitis-induced tubular dilatation and the loss of brush border in male Sprague–Dawley rats. These improvements in renal structure were accompanied by decreases in serum cystatin-C levels, reduced renal oxidative stress, diminished Stat-3 phosphorylation and an attenuation of caspase-3 cleavage suggesting that the nanoparticle treatment improved renal glomerular filtration rate, diminished renal inflammation and reduced renal apoptosis. Consistent with these data, further analysis demonstrated that the CeO₂ nanoparticle treatment diminished peritonitis-induced increases in serum kidney injury molecule-1 (KIM-1), osteopontin, β-2 microglobulin and vascular endothelial growth factor-A (VEGF-A) levels. In addition, the nanoparticle attenuated peritonitis-induced hyperglycemia along with increases in blood urea nitrogen (BUN), serum potassium and sodium.

Conclusion

CeO₂ nanoparticles scavenge reactive oxygen species and attenuate polymicrobial insult induced increase in inflammatory mediators and subsequent AKI. Taken together, the data indicate that CeO₂ nanoparticles may be useful as an alternative therapeutic agent or in conjunction with standard medical care for the treatment of peritonitis induced acute kidney injury.

Endurance training prevents TWEAK but not myostatin-mediated cardiac remodelling in cancer cachexia

Strategies to prevent tumour burden-induced cardiac remodelling that might progress to heart failure are necessary to improve patients' health outcomes and tolerability to cancer therapies. Exercise has been suggested as a measure to prevent cardiac damage; however, its effectiveness on regulating cardiac remodelling secondary to cancer was never addressed. Using an animal model of mammary tumorigenesis, we studied the impact of 35weeks of endurance training on heart, focusing on the signalling pathways modulated by pro-inflammatory and wasting cytokines. The cardiac fibrosis and myofiber disorganization induced by tumour burden was paralleled by the increase of myostatin and TWEAK with the activation of signalling pathways involving Smad-3, NF-κB, TRAF-6 and atrogin-1. The activation of Akt/mTOR was observed in heart from rats with tumours, for which contributed the extracellular matrix. Endurance training prevented the increase of serum and cardiac TWEAK promoted by cancer, as well as the activation of NF-κB, TRAF6, atrogin-1 and p70S6K in heart. Data highlight the impact of exercise in the modulation of signalling pathways activated by wasting cytokines and the resulting outcomes on heart adaptation. Future studies focused on the cellular pathways underlying cardiac remodelling will assist in the development of exercise programs targeting cancer-related cardiac alterations.

Concurrent evolution of cancer cachexia and heart failure: bilateral effects exist

Cancer cachexia is defined as a multifactorial syndrome of involuntary weight loss characterized by an ongoing loss of skeletal muscle mass and progressive functional impairment. It is postulated that cardiac dysfunction/atrophy parallels skeletal muscle atrophy in cancer cachexia. Cardiotoxic chemotherapy may additionally result in cardiac dysfunction and heart failure in some cancer patients. Heart failure thus may be a consequence of either ongoing cachexia or chemotherapy-induced cardiotoxicity; at the same time, heart failure can result in cachexia, especially muscle wasting. Therefore, the subsequent heart failure and cardiac cachexia can exacerbate the existing cancer-induced cachexia. We discuss these bilateral effects between cancer cachexia and heart failure in cancer patients. Since cachectic patients are more susceptible to chemotherapy-induced toxicity overall, this may also include increased cardiotoxicity of antineoplastic agents. Patients with cachexia could thus be doubly unfortunate, with cachexia-related cardiac dysfunction/heart failure and increased susceptibility to cardiotoxicity during treatment. Cardiovascular risk factors as well as pre-existing heart failure seem to exacerbate cardiac susceptibility against cachexia and increase the rate of cardiac cachexia. Hence, chemotherapy-induced cardiotoxicity, cardiovascular risk factors, and pre-existing heart failure may accelerate the vicious cycle of cachexia-heart failure. The impact of cancer cachexia on cardiac dysfunction/heart failure in cancer patients has not been thoroughly studied. A combination of serial echocardiography for detection of cachexia-induced cardiac remodeling and computed tomography image analysis for detection of skeletal muscle wasting would appear a practical and non-invasive approach to develop an understanding of cardiac structural/functional alterations that are directly related to cachexia.

Ampelopsin suppresses breast carcinogenesis by inhibiting the mTOR signalling pathway

The mammalian target of rapamycin (mTOR), which is a master regulator of cellular catabolism and anabolism, plays an important role in tumourigenesis and progression. In this study, we report the chemopreventive effect of the dietary compound ampelopsin (AMP) on breast carcinogenesis in vivo and in vitro, which acts by inhibiting the mTOR signalling pathway. Our study indicates that AMP treatment effectively suppresses 1-methyl-1-nitrosourea (MNU)-induced breast carcinogenesis in rats and inhibits 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) and benzo[a]pyrene (B[a]P)-induced cellular carcinogenesis. Additionally, AMP inhibits the growth of breast cancer cells in vitro and in vivo. The activity of mTOR kinase was found to be significantly increased in a time-dependent manner during chronic breast carcinogenesis, and this increase can be suppressed by AMP co-treatment. AMP also effectively suppresses mTOR activity in breast cancer MDA-MB-231 cells. We also demonstrated that AMP is an effective mTOR inhibitor that binds to one site on the mTOR target in two ways. Further studies confirmed that AMP inhibits the activation of Akt, suppresses the formation of mTOR complexes (mTORC)1/2 by dissociating regulatory-associated protein of mTOR and rapamycin-insensitive companion of mTOR and, consequently, decreases the activation of the downstream targets of mTOR, including ribosomal p70-S6 kinase, ribosomal protein S6, eukaryotic translation initiation factor 4B and eukaryotic translation initiation factor 4E-binding protein 1. These finding suggest that AMP is a bioactive natural chemopreventive agent against breast carcinogenesis and is an effective mTOR inhibitor that may be developed as a useful chemotherapeutic agent in the treatment of breast cancer.

Coming back: autophagy in cachexia

PURPOSE OF REVIEW

Cachexia is a complex syndrome characterized by body weight loss, tissue wasting, systemic inflammation, metabolic abnormalities, and altered nutritional status. One of the most prominent features of cachexia is the loss of muscle mass, mainly because of increased protein degradation rates. This review is aimed at discussing the involvement of autophagy in the pathogenesis of muscle wasting in cachexia.

RECENT FINDINGS

Modulations of muscle mass in the adult reflect an imbalance between protein synthesis and degradation rates. Muscle depletion in cachexia is associated with increased protein breakdown, mainly involving the pathways dependent on ubiquitin-proteasome and autophagy-lysosomes. This latter, in particular, was considered not relevant for a long time. Just in the last years, autophagy was shown to contribute to the pathogenesis of muscle wasting not only in myopathies because of intrinsic muscle defects, but also in muscle depletion associated with conditions such as sepsis, chronic obstructive pulmonary disease, glucocorticoid treatment, cancer cachexia, and aging.

SUMMARY

The present review highlights that both excess and defective autophagy are relevant to the onset of muscle depletion, and draws some considerations about possible therapeutic intervention aimed at modulating autophagy in order to improve muscle trophism.

VIDEO ABSTRACT

http://links.lww.com/COCN/A5.