Dysregulation of metabolic-associated pathways in muscle of breast cancer patients: preclinical evaluation of interleukin-15 targeting fatigue

Myogenic microRNAs as Therapeutic Targets for Skeletal Muscle Mass Wasting in Breast Cancer Models

Breast cancer is the type of cancer with the highest prevalence in women worldwide. Skeletal muscle atrophy is an important prognostic factor in women diagnosed with breast cancer. This atrophy stems from disrupted skeletal muscle homeostasis, triggered by diminished anabolic signalling and heightened inflammatory conditions, culminating in an upregulation of skeletal muscle proteolysis gene expression. The importance of delving into research on modulators of skeletal muscle atrophy, such as microRNAs (miRNAs), which play a crucial role in regulating cellular signalling pathways involved in skeletal muscle protein synthesis and degradation, has been recognised. This holds true for conditions of homeostasis as well as pathologies like cancer. However, the determination of specific miRNAs that modulate skeletal muscle atrophy in breast cancer conditions has not yet been explored. In this narrative review, we aim to identify miRNAs that could directly or indirectly influence skeletal muscle atrophy in breast cancer models to gain an updated perspective on potential therapeutic targets that could be modulated through resistance exercise training, aiming to mitigate the loss of skeletal muscle mass in breast cancer patients.

Cancer-associated muscle weakness - From triggers to molecular mechanisms

Skeletal muscle weakness is a debilitating consequence of many malignancies. Muscle weakness has a negative impact on both patient wellbeing and outcome in a range of cancer types and can be the result of loss of muscle mass (i.e. muscle atrophy, cachexia) and occur independently of muscle atrophy or cachexia. There are multiple cancer specific triggers that can initiate the progression of muscle weakness, including the malignancy itself and the tumour environment, as well as chemotherapy, radiotherapy and malnutrition. This can induce weakness via different routes: 1) impaired intrinsic capacity (i.e., contractile dysfunction and intramuscular impairments in excitation-contraction coupling or crossbridge cycling), 2) neuromuscular disconnection and/or 3) muscle atrophy. The mechanisms that underlie these pathways are a complex interplay of inflammation, autophagy, disrupted protein synthesis/degradation, and mitochondrial dysfunction. The current lack of therapies to treat cancer-associated muscle weakness highlight the critical need for novel interventions (both pharmacological and non-pharmacological) and mechanistic insight. Moreover, most research in the field has placed emphasis on directly improving muscle mass to improve muscle strength. However, accumulating evidence suggests that loss of muscle function precedes atrophy. This review primarily focuses on cancer-associated muscle weakness, independent of cachexia, and provides a solid background on the underlying mechanisms, methodology, current interventions, gaps in knowledge, and limitations of research in the field. Moreover, we have performed a mini-systematic review of recent research into the mechanisms behind muscle weakness in specific cancer types, along with the main pathways implicated.

Involvement of N4BP2L1, PLEKHA4, and BEGAIN genes in breast cancer and muscle cell development

Patients with breast cancer show altered expression of genes within the pectoralis major skeletal muscle cells of the breast. Through analyses of The Cancer Genome Atlas (TCGA)-breast cancer (BRCA), we identified three previously uncharacterized putative novel tumor suppressor genes expressed in normal muscle cells, whose expression was downregulated in breast tumors. We found that NEDD4 binding protein 2-like 1 (N4BP2L1), pleckstrin homology domain-containing family A member 4 (PLEKHA4), and brain-enriched guanylate kinase-associated protein (BEGAIN) that are normally highly expressed in breast myoepithelial cells and smooth muscle cells were significantly downregulated in breast tumor tissues of a cohort of 50 patients with this cancer. Our data revealed that the low expression of PLEKHA4 in patients with menopause below 50 years correlated with a higher risk of breast cancer. Moreover, we identified N4BP2L1 and BEGAIN as potential biomarkers of HER2-positive breast cancer. Furthermore, low BEGAIN expression in breast cancer patients with blood fat, heart problems, and diabetes correlated with a higher risk of this cancer. In addition, protein and RNA expression analysis of TCGA-BRCA revealed N4BP2L1 as a promising diagnostic protein biomarker in breast cancer. In addition, the in silico data of scRNA-seq showed high expression of these genes in several cell types of normal breast tissue, including breast myoepithelial cells and smooth muscle cells. Thus, our results suggest their possible tumor-suppressive function in breast cancer and muscle development.

Association of computed tomography scan-assessed body composition with immune and PI3K/AKT pathway proteins in distinct breast cancer tumor components

This hypothesis-generating study aims to examine the extent to which computed tomography-assessed body composition phenotypes are associated with immune and PI3K/AKT signaling pathways in breast tumors. A total of 52 patients with newly diagnosed breast cancer were classified into four body composition types: adequate (lowest two tertiles of total adipose tissue [TAT]) and highest two tertiles of total skeletal muscle [TSM] areas); high adiposity (highest tertile of TAT and highest two tertiles of TSM); low muscle (lowest tertile of TSM and lowest two tertiles of TAT); and high adiposity with low muscle (highest tertile of TAT and lowest tertile of TSM). Immune and PI3K/AKT pathway proteins were profiled in tumor epithelium and the leukocyte-enriched stromal microenvironment using GeoMx (NanoString). Linear mixed models were used to compare log2-transformed protein levels. Compared with the normal type, the low muscle type was associated with higher expression of INPP4B (log2-fold change = 1.14, p = 0.0003, false discovery rate = 0.028). Other significant associations included low muscle type with increased CTLA4 and decreased pan-AKT expression in tumor epithelium, and high adiposity with increased CD3, CD8, CD20, and CD45RO expression in stroma (P<0.05; false discovery rate >0.2). With confirmation, body composition can be associated with signaling pathways in distinct components of breast tumors, highlighting the potential utility of body composition in informing tumor biology and therapy efficacies.

Preclinical Multi-Omic Assessment of Pioglitazone in Skeletal Muscles of Mice Implanted with Human HER2/neu Overexpressing Breast Cancer Xenografts

Breast cancer (BC) is the most prevalent cancer worldwide and is accompanied by fatigue during both active disease and remission in the majority of cases. Our lab has measured fatigue in isolated muscles from treatment-naive BC patient-derived orthotopic xenograft (BC-PDOX) mice. Here, we conducted a preclinical trial of pioglitazone in BC-PDOX mice to determine its efficacy in ameliorating BC-induced muscle fatigue, as well as its effects on transcriptomic, metabolomic, and lipidomic profiles in skeletal muscle.

Methods

The pioglitazone and vehicle groups were treated orally for 4 weeks upon reaching a tumor volume of 600 mm3. Whole-animal indirect calorimetry was used to evaluate systemic metabolic states. The transcriptome was profiled using short-read bulk RNA sequencing (RNA-seq). Liquid chromatography-tandem mass spectrometry (LC-MS/MS) was used to profile the metabolome and lipidome. Fast and slow skeletal muscle function were evaluated using isolated ex vivo testing.

Results

Pioglitazone was associated with a significant overall decrease in metabolic rate, with no changes in substrate utilization. RNA-seq supported the downstream effects of pioglitazone on target genes and displayed considerable upregulation of mitochondrial bioenergetic pathways. Skeletal muscle metabolomic and lipidomic profiles exhibited dysregulation in response to BC, which was partially restored in pioglitazone-treated mice compared to vehicle-treated BC-PDOX mice. Despite molecular support for pioglitazone's efficacy, isolated muscle function was not affected by pioglitazone treatment.

Conclusions

BC induces multi-omic dysregulation in skeletal muscle, which pioglitazone partially ameliorates. Future research should focus on profiling systemic metabolic dysfunction, identifying molecular biomarkers of fatigue, and testing alternative pioglitazone treatment regimens.

Mechanisms of exercise in the treatment of lung cancer - a mini-review

Lung cancer constitutes a formidable menace to global health and well-being, as its incidence and mortality rate escalate at an alarming pace. In recent years, research has indicated that exercise has potential roles in both the prevention and treatment of lung cancer. However, the exact mechanism of the coordinating effect of exercise on lung cancer treatment is unclear, limiting the use of exercise in clinical practice. The purpose of this review is to explore the mechanisms through which exercise exerts its anticancer effects against lung cancer. This review will analyze the biological basis of exercise's anticancer effects on lung cancer, with a focus on aspects such as the tumor microenvironment, matrix regulation, apoptosis and angiogenesis. Finally, we will discuss future research directions and potential clinical applications.

Cancer cachexia: molecular mechanisms and treatment strategies

Muscle wasting is a consequence of physiological changes or a pathology characterized by increased catabolic activity that leads to progressive loss of skeletal muscle mass and strength. Numerous diseases, including cancer, organ failure, infection, and aging-associated diseases, are associated with muscle wasting. Cancer cachexia is a multifactorial syndrome characterized by loss of skeletal muscle mass, with or without the loss of fat mass, resulting in functional impairment and reduced quality of life. It is caused by the upregulation of systemic inflammation and catabolic stimuli, leading to inhibition of protein synthesis and enhancement of muscle catabolism. Here, we summarize the complex molecular networks that regulate muscle mass and function. Moreover, we describe complex multi-organ roles in cancer cachexia. Although cachexia is one of the main causes of cancer-related deaths, there are still no approved drugs for cancer cachexia. Thus, we compiled recent ongoing pre-clinical and clinical trials and further discussed potential therapeutic approaches for cancer cachexia.

Exercise-induced IL-15 acted as a positive prognostic implication and tumor-suppressed role in pan-cancer

Objective: Exercise can produce a large number of cytokines that may benefit cancer patients, including Interleukin 15 (IL-15). IL-15 is a cytokine that has multiple functions in regulating the adaptive and innate immune systems and tumorigenesis of lung and breast cancers. However, the roles of IL-15 in other types of cancer remain unknown. In this article, we try to systematically analyze if IL-15 is a potential molecular biomarker for predicting patient prognosis in pan-cancer and its connection with anti-cancer effects of exercise. Methods: The expression of IL-15 was detected by The Cancer Genome Atlas (TCGA) database, Human protein Atlas (HPA), and Genotype Tissue-Expression (GTEX) database. Analysis of IL-15 genomic alterations and protein expression in human organic tissues was analyzed by the cBioPortal database and HPA. The correlations between IL-15 expression and survival outcomes, clinical features, immune-associated cell infiltration, and ferroptosis/cuproptosis were analyzed using the TCGA, ESTIMATE algorithm, and TIMER databases. Gene Set Enrichment Analysis (GSEA) was performed to evaluate the biological functions of IL-15 in pan-cancer. Results: The differential analysis suggested that the level of IL-15 mRNA expression was significantly downregulated in 12 tumor types compared with normal tissues, which is similar to the protein expression in most cancer types. The high expression of IL-15 could predict the positive survival outcome of patients with LUAD (lung adenocarcinoma), COAD (colon adenocarcinoma), COADREAD (colon and rectum adenocarcinoma), ESCA (esophageal carcinoma), SKCM (skin cutaneous melanoma), UCS (uterine carcinosarcoma), and READ (rectum adenocarcinoma). Moreover, amplification was found to be the most frequent mutation type of IL-15 genomic. Furthermore, the expression of IL-15 was correlated to the infiltration levels of various immune-associated cells in pan-cancer assessed by the ESTIMATE algorithm and TIMER database. In addition, IL-15 is positively correlated with ferroptosis/cuproptosis-related genes (ACSL4 and LIPT1) in pan-cancer. Levels of IL-15 were reported to be elevated in humans for 10-120 min following an acute exercise. Therefore, we hypothesized that the better prognosis of pan-cancer patients with regular exercise may be achieved by regulating level of IL-15. Conclusion: Our results demonstrated that IL-15 is a potential molecular biomarker for predicting patient prognosis, immunoreaction, and ferroptosis/cuproptosis in pan-cancer and partly explained the anti-cancer effects of exercise.

Comprehensive Analysis of the Expression and Prognosis for Tripartite Motif-Containing Genes in Breast Cancer

Tripartite motif-containing genes (TRIMs), with a ubiquitin ligase’s function, play critical roles in antitumor immunity by activating tumor-specific immune responses and stimulating tumor proliferation, thus affecting patient outcomes. However, the expression pattern and prognostic values of TRIMs in breast cancer (BC) are not well clarified. In this study, several datasets and software were integrated to perform a comprehensive analysis of the expression pattern in TRIMs and investigate their prognosis values in BC. We found that TRIM59/46 were significantly upregulated and TRIM66/52-AS1/68/7/2/9/29 were decreased in BC and validated them using an independent cohort. The expression of numerous TRIMs are significantly correlated with BC molecular subtypes, but not with tumor stages or patient age at diagnosis. Higher expression of TRIM3/14/69/45 and lower expressions of TRIM68/2 were associated with better overall survival in BC using the Kaplan–Meier analysis. The multivariate Cox proportional hazards model identified TRIM45 as an independent prognostic marker. Further analysis of single-cell RNA-seq data revealed that most TRIMs are also expressed in nontumor cells. Higher expression of some TRIMs in the immune or stromal cells suggests an important role of TRIMs in the BC microenvironment. Functional enrichment of the co-expression genes indicates that they may be involved in muscle contraction and interferon-gamma signaling pathways. In brief, through the analysis, we provided several TRIMs that may contribute to the tumor progression and TRIM45 as a potential new prognostic biomarker for BC.

Dermcidin Enhances the Migration, Invasion, and Metastasis of Hepatocellular Carcinoma Cells In Vitro and In Vivo

BACKGROUND AND AIMS

Hepatocellular carcinoma (HCC) is a common primary liver neoplasm with high mortality. Dermcidin (DCD), an antimicrobial peptide, has been reported to participate in oncogenesis. This study assessed the effects and underlying molecular events of DCD overexpression and knockdown on the regulation of HCC progression in vitro and in vivo.

METHODS

The serum DCD level was detected using enzyme-linked immunosorbent assay. DCD overexpression, knockdown, and Ras-related C3 botulinum toxin substrate 1 (Rac1) rescue were performed in SK-HEP-1 cells using plasmids. Immunofluorescence staining, quantitative PCR, and Western blotting were used to detect the expression of different genes and proteins. Differences in HCC cell migration and invasion were detected by Transwell migration and invasion assays. A nude mouse HCC cell orthotopic model was employed to verify the in vitro data.

RESULTS

The level of serum DCD was higher in patients with HCC and in SK-HEP-1 cells. DCD overexpression caused upregulation of DCD, fibronectin, Rac1, and cell division control protein 42 homologue (Cdc42) mRNA and proteins as well as actin-related protein 2/3 (Arp2/3) protein (but reduced Arp2/3 mRNA levels) and activated Rac1 and Cdc42. Phenotypically, DCD overexpression induced HCC cell migration and invasion in vitro, whereas knockout of DCD expression had the opposite effects. A Rac1 rescue experiment in DCD-knockdown HCC cells increased HCC cell migration and invasion and increased the levels of active Rac1/total Rac1, Wiskott-Aldrich syndrome family protein (WASP), Arp2/3, and fibronectin. DCD overexpression induced HCC cell metastasis to the abdomen and liver in vivo.

CONCLUSIONS

DCD promotes HCC cell migration, invasion, and metastasis through upregulation of noncatalytic region of tyrosine kinase adaptor protein 1 (Nck1), Rac1, Cdc42, WASP, and Arp2/3, which induce actin cytoskeletal remodeling and fibronectin-mediated cell adhesion in HCC cells.

Chemotherapy impairs skeletal muscle mitochondrial homeostasis in early breast cancer patients

BACKGROUND

Chemotherapy is extensively used to treat breast cancer and is associated with skeletal muscle deconditioning, which is known to reduce patients' quality of life, treatment efficiency, and overall survival. To date, skeletal muscle mitochondrial alterations represent a major aspect explored in breast cancer patients; nevertheless, the cellular mechanisms remain relatively unknown. This study was dedicated to investigating overall skeletal muscle mitochondrial homeostasis in early breast cancer patients undergoing chemotherapy, including mitochondrial quantity, function, and dynamics.

METHODS

Women undergoing (neo)adjuvant anthracycline-cyclophosphamide and taxane-based chemotherapy participated in this study (56 ± 12 years). Two muscle biopsies were collected from the vastus lateralis muscle before the first and after the last chemotherapy administration. Mitochondrial respiratory capacity, reactive oxygen species production, and western blotting analyses were performed.

RESULTS

Among the 11 patients, we found a decrease in key markers of mitochondrial quantity, reaching -52.0% for citrate synthase protein levels (P = 0.02) and -38.2% for VDAC protein levels (P = 0.04). This mitochondrial content loss is likely explained by reduced mitochondrial biogenesis, as evidenced by a decrease in PGC-1α1 protein levels (-29.5%; P = 0.04). Mitochondrial dynamics were altered, as documented by a decrease in MFN2 protein expression (-33.4%; P = 0.01), a key marker of mitochondrial outer membrane fusion. Mitochondrial fission is a prerequisite for mitophagy activation, and no variation was found in either key markers of mitochondrial fission (Fis1 and DRP1) or mitophagy (Parkin, PINK1, and Mul1). Two contradictory hypotheses arise from these results: defective mitophagy, which probably increases the number of damaged and fragmented mitochondria, or a relative increase in mitophagy through elevated mitophagic potential (Parkin/VDAC ratio; +176.4%; P < 0.02). Despite no change in mitochondrial respiratory capacity and COX IV protein levels, we found an elevation in H₂ O₂ production (P < 0.05 for all substrate additions) without change in antioxidant enzymes. We investigated the apoptosis pathway and found an increase in the protein expression of the apoptosis initiation marker Bax (+72.0%; P = 0.04), without variation in the anti-apoptotic protein Bcl-2.

CONCLUSIONS

This study demonstrated major mitochondrial alterations subsequent to chemotherapy in early breast cancer patients: (i) a striking reduction in mitochondrial biogenesis, (ii) altered mitochondrial dynamics and potential mitophagy defects, (iii) exacerbated H₂ O₂ production, and (iv) increased initiation of apoptosis. All of these alterations likely explain, at least in part, the high prevalence of skeletal muscle and cardiorespiratory deconditioning classically observed in breast cancer patients.

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.

From bench to bedside: updates in basic science, translational and clinical research on muscle fatigue in cancer cachexia

PURPOSE OF REVIEW

Cancer cachexia is a syndrome of loss of weight and muscle mass that leads to reduced strength, poor physical performance and functional impairment. Muscular fatigue is a distressing syndrome that patients with cachexia suffer from and can impair quality of life. Here, we review recent updates in muscular fatigue in cancer cachexia research with a focus on mechanisms, biomarkers and potential therapies.

RECENT FINDINGS

Both in mice and humans, research has shown that muscle fatigue can be independent of muscular atrophy and can happen early in cancer development or in precachexia. Inflammatory pathways, mitochondrial dysfunction and gut microbiota have recently been studied to play an important role in muscle fatigue in preclinical models. Exercise can target these pathways and has been studied as a therapeutic intervention to improve muscle fatigue.

SUMMARY

Heightened inflammation within muscle, altered muscle function and muscle fatigue can begin prior to clinical evidence of cachexia, making early recognition and intervention challenging. The emergence of cachexia mouse models and translational and clinical research studying muscle fatigue will hopefully lead to new therapies targeting the underlying mechanisms of cancer cachexia. Exercise will need to be tested in larger randomized studies before entering into daily practice.

Voluntary wheel running ameliorates select paclitaxel chemotherapy-induced sickness behaviors and associated melanocortin signaling

While chemotherapy remains a common cancer treatment, it is associated with debilitating side effects (e.g., anorexia, weight loss, and fatigue) that adversely affect patient quality of life and increase mortality. However, the mechanisms underlying taxane chemotherapy-induced side effects, and effective treatments to ameliorate them, are not well-established. Here, we tested the longitudinal relationship between a clinically-relevant paclitaxel regimen, inflammation, and sickness behaviors (loss of body mass, anorexia, fever, and fatigue) in adult, female mice. Furthermore, we sought to identify the extent to which voluntary exercise (wheel running) attenuates paclitaxel-induced sickness behaviors and underlying central pathways. Body mass and food intake decreased following six doses of chemotherapy treatment relative to vehicle controls, lasting less than 5 days after the last dose. Paclitaxel treatment also transiently decreased locomotion (open field test), voluntary wheel running, home-cage locomotion, and core body temperature without affecting motor coordination (rotarod task). Circulating interleukin (IL)-6 and hypothalamic Il1b gene expression remained elevated in chemotherapy-treated mice at least 3 days after the last dose. Exercise intervention did not ameliorate fatigue or inflammation, but hastened recovery from paclitaxel-induced weight loss. Body mass recovery was associated with the wheel running-induced recovery of body composition, paclitaxel-induced alterations to hypothalamic melanocortin signaling, and associated peripheral circulating hormones (ghrelin and leptin). The present findings demonstrate the benefits of exercise on faster recovery from paclitaxel-induced body mass loss and deficits in melanocortin signaling and suggests the development of therapies targeting the melanocortin pathway to reduce paclitaxel-induced weight loss.

Breast cancer-associated skeletal muscle mitochondrial dysfunction and lipid accumulation is reversed by PPARG

The peroxisome proliferator-activated receptors (PPARs) have been previously implicated in the pathophysiology of skeletal muscle dysfunction in women with breast cancer (BC) and animal models of BC. This study investigated alterations induced in skeletal muscle by BC-derived factors in an in vitro conditioned media (CM) system and tested the hypothesis that BC cells secrete a factor that represses PPAR-γ (PPARG) expression and its transcriptional activity, leading to downregulation of PPARG target genes involved in mitochondrial function and other metabolic pathways. We found that BC-derived factors repress PPAR-mediated transcriptional activity without altering protein expression of PPARG. Furthermore, we show that BC-derived factors induce significant alterations in skeletal muscle mitochondrial function and lipid accumulation, which are rescued with exogenous expression of PPARG. The PPARG agonist drug rosiglitazone was able to rescue BC-induced lipid accumulation but did not rescue effects of BC-derived factors on PPAR-mediated transcription or mitochondrial function. These data suggest that BC-derived factors alter lipid accumulation and mitochondrial function via different mechanisms that are both related to PPARG signaling, with mitochondrial dysfunction likely being altered via repression of PPAR-mediated transcription, and lipid accumulation being altered via transcription-independent functions of PPARG.

Aging-associated skeletal muscle defects in HER2/Neu transgenic mammary tumor model

BACKGROUND

Loss of skeletal muscle volume and resulting in functional limitations are poor prognostic markers in breast cancer patients. Several molecular defects in skeletal muscle including reduced MyoD levels and increased protein turn over due to enhanced proteosomal activity have been suggested as causes of skeletal muscle loss in cancer patients. However, it is unknown whether molecular defects in skeletal muscle are dependent on tumor etiology.

METHODS

We characterized functional and molecular defects of skeletal muscle in MMTV-Neu (Neu+) mice (n= 6-12), an animal model that represents HER2+ human breast cancer, and compared the results with well-characterized luminal B breast cancer model MMTV-PyMT (PyMT+). Functional studies such as grip strength, rotarod performance, and ex vivo muscle contraction were performed to measure the effects of cancer on skeletal muscle. Expression of muscle-enriched genes and microRNAs as well as circulating cytokines/chemokines were measured. Since NF-κB pathway plays a significant role in skeletal muscle defects, the ability of NF-κB inhibitor dimethylaminoparthenolide (DMAPT) to reverse skeletal muscle defects was examined.

RESULTS

Neu+ mice showed skeletal muscle defects similar to accelerated aging. Compared to age and sex-matched wild type mice, Neu+ tumor-bearing mice had lower grip strength (202±6.9 vs. 179±6.8 g grip force, p=0.0069) and impaired rotarod performance (108±12.1 vs. 30±3.9 seconds, P<0.0001), which was consistent with reduced muscle contractibility (p<0.0001). Skeletal muscle of Neu+ mice (n=6) contained lower levels of CD82+ (16.2±2.9 vs 9.0±1.6) and CD54+ (3.8±0.5 vs 2.4±0.4) muscle stem and progenitor cells (p<0.05), suggesting impaired capacity of muscle regeneration, which was accompanied by decreased MyoD, p53 and miR-486 expression in muscles (p<0.05). Unlike PyMT+ mice, which showed skeletal muscle mitochondrial defects including reduced mitochondria levels and Pgc1β, Neu+ mice displayed accelerated aging-associated changes including muscle fiber shrinkage and increased extracellular matrix deposition. Circulating "aging factor" and cachexia and fibromyalgia-associated chemokine Ccl11 was elevated in Neu+ mice (1439.56±514 vs. 1950±345 pg/ml, p<0.05). Treatment of Neu+ mice with DMAPT significantly restored grip strength (205±6 g force), rotarod performance (74±8.5 seconds), reversed molecular alterations associated with skeletal muscle aging, reduced circulating Ccl11 (1083.26 ±478 pg/ml), and improved animal survival.

CONCLUSIONS

These results suggest that breast cancer subtype has a specific impact on the type of molecular and structure changes in skeletal muscle, which needs to be taken into consideration while designing therapies to reduce breast cancer-induced skeletal muscle loss and functional limitations.

Physical Activity as an Imperative Support in Breast Cancer Management

Breast cancer (BC) is the most common malignancy and the second cause of cancer-related death among women. It is estimated that 9 in 10 cases of BC are due to non-genetic factors, and approximately 25% to 30% of total breast cancer cases should be preventable only by lifestyle interventions. In this context, physical activity represents an excellent and accessible approach not only for the prevention, but also for being a potential support in the management of breast cancer. The present review will collect the current knowledge of physical activity in the background of breast cancer, exploring its systemic and molecular effects, considering important variables in the training of these women and the evidence regarding the benefits of exercise on breast cancer survival and prognosis. We will also summarize the various effects of physical activity as a co-adjuvant therapy in women receiving different treatments to deal with its adverse effects. Finally, we will reveal the impact of physical activity in the enhancement of quality of life of these patients, to conclude the central role that exercise must occupy in breast cancer management, in an adequate context of a healthy lifestyle.

Myokines in treatment-naïve patients with cancer-associated cachexia

Cancer-associated cachexia is a complex metabolic syndrome characterized by weight loss and systemic inflammation. Muscle loss and fatty infiltration into muscle are associated with poor prognosis in cancer patients. Skeletal muscle secretes myokines, factors with autocrine, paracrine and/or endocrine action, which may be modified by or play a role in cachexia. This study examined myokine content in the plasma, skeletal muscle and tumor homogenates from treatment-naïve patients with gastric or colorectal stages I-IV cancer with cachexia (CC, N = 62), or not (weight stable cancer, WSC, N = 32). Myostatin, interleukin (IL) 15, follistatin-like protein 1 (FSTL-1), fatty acid binding protein 3 (FABP3), irisin and brain-derived neurotrophic factor (BDNF) protein content in samples was measured with Multiplex technology; body composition and muscle lipid infiltration were evaluated in computed tomography, and quantification of triacylglycerol (TAG) in the skeletal muscle. Cachectic patients presented lower muscle FSTL-1 expression (p = 0.047), higher FABP3 plasma content (p = 0.0301) and higher tumor tissue expression of FABP3 (p = 0.0182), IL-15 (p = 0.007) and irisin (p = 0.0110), compared to WSC. Neither muscle TAG content, nor muscle attenuation were different between weight stable and cachectic patients. Lumbar adipose tissue (AT) index, visceral AT index and subcutaneous AT index were lower in CC (p = 0.0149, p = 0.0455 and p = 0.0087, respectively), who also presented lower muscularity in the cohort (69.2% of patients; p = 0.0301), compared to WSC. The results indicate the myokine profile in skeletal muscle, plasma and tumor is impacted by cachexia. These findings show that myokines eventually affecting muscle wasting may not solely derive from the muscle itself (as the tumor also may contribute to the systemic scenario), and put forward new perspectives on cachexia treatment targeting myokines and associated receptors and pathways.

EO771, is it a well-characterized cell line for mouse mammary cancer model? Limit and uncertainty

Among mouse mammary tumor models, syngeneic cell lines present an advantage for the study of immune response. However, few of these models are well characterized. The tumor line EO771 is derived from spontaneous breast cancer of C57BL/6 mice. These cells are widely used but are referenced under different names: EO771, EO 771, and E0771. The characteristics of the EO771 cells are well described but some data are contradictory. This cell line presents the great interest of developing an immunocompetent neoplastic model using an orthotopic implantation reflecting the mammary tumors encountered in breast cancer patients. This review presents the phenotype characteristics of EO771 and its sensitivity to nutrients and different therapies such as radiotherapy, chemotherapy, hormone therapy, and immunotherapy.

Skeletal muscle reprogramming by breast cancer regardless of treatment history or tumor molecular subtype

Increased susceptibility to fatigue is a negative predictor of survival commonly experienced by women with breast cancer (BC). Here, we sought to identify molecular changes induced in human skeletal muscle by BC regardless of treatment history or tumor molecular subtype using RNA-sequencing (RNA-seq) and proteomic analyses. Mitochondrial dysfunction was apparent across all molecular subtypes, with the greatest degree of transcriptomic changes occurring in women with HER2/neu-overexpressing tumors, though muscle from patients of all subtypes exhibited similar pathway-level dysregulation. Interestingly, we found no relationship between anticancer treatments and muscle gene expression, suggesting that fatigue is a product of BC per se rather than clinical history. In vitro and in vivo experimentation confirmed the ability of BC cells to alter mitochondrial function and ATP content in muscle. These data suggest that interventions supporting muscle in the presence of BC-induced mitochondrial dysfunction may alleviate fatigue and improve the lives of women with BC.

Cancer Cachexia and Related Metabolic Dysfunction

Cancer cachexia is a complex multifactorial syndrome marked by a continuous depletion of skeletal muscle mass associated, in some cases, with a reduction in fat mass. It is irreversible by nutritional support alone and affects up to 74% of patients with cancer-dependent on the underlying type of cancer-and is associated with physical function impairment, reduced response to cancer-related therapy, and higher mortality. Organs, like muscle, adipose tissue, and liver, play an important role in the progression of cancer cachexia by exacerbating the pro- and anti-inflammatory response initially activated by the tumor and the immune system of the host. Moreover, this metabolic dysfunction is produced by alterations in glucose, lipids, and protein metabolism that, when maintained chronically, may lead to the loss of skeletal muscle and adipose tissue. Although a couple of drugs have yielded positive results in increasing lean body mass with limited impact on physical function, a single therapy has not lead to effective treatment of this condition. Therefore, a multimodal intervention, including pharmacological agents, nutritional support, and physical exercise, may be a reasonable approach for future studies to better understand and prevent the wasting of body compartments in patients with cancer cachexia.

Recent advances in cardio-oncology: a report from the 'Heart Failure Association 2019 and World Congress on Acute Heart Failure 2019'

While anti-cancer therapies, including chemotherapy, immunotherapy, radiotherapy, and targeted therapy, are constantly advancing, cardiovascular toxicity has become a major challenge for cardiologists and oncologists. This has led to an increasing demand of cardio-oncology units in Europe and a growing interest of clinicians and researchers. The Heart Failure 2019 meeting of the Heart Failure Association of the European Society of Cardiology in Athens has therefore created a scientific programme that included four dedicated sessions on the topic along with several additional lectures. The major points that were discussed at the congress included the implementation and delivery of a cardio-oncology service, the collaboration among cardio-oncology experts, and the risk stratification, prevention, and early recognition of cardiotoxicity. Furthermore, sessions addressed the numerous different anti-cancer therapies associated with cardiotoxic effects and provided guidance on how to treat cancer patients who develop cardiovascular disease before, during, and after treatment.

Clinical and biological characterization of skeletal muscle tissue biopsies of surgical cancer patients

BACKGROUND

Researchers increasingly use intraoperative muscle biopsy to investigate mechanisms of skeletal muscle atrophy in patients with cancer. Muscles have been assessed for morphological, cellular, and biochemical features. The aim of this study was to conduct a state-of-the-science review of this literature and, secondly, to evaluate clinical and biological variation in biopsies of rectus abdominis (RA) muscle from a cohort of patients with malignancies.

METHODS

Literature was searched for reports on muscle biopsies from patients with a cancer diagnosis. Quality of reports and risk of bias were assessed. Data abstracted included patient characteristics and diagnoses, sample size, tissue collection and biobanking procedures, and results. A cohort of cancer patients (n = 190, 88% gastrointestinal malignancies), who underwent open abdominal surgery as part of their clinical care, consented to RA biopsy from the site of incision. Computed tomography (CT) scans were used to quantify total abdominal muscle and RA cross-sectional areas and radiodensity. Biopsies were assessed for muscle fibre area (μm² ), fibre types, myosin heavy chain isoforms, and expression of genes selected for their involvement in catabolic pathways of muscle.

RESULTS

Muscle biopsy occurred in 59 studies (total N = 1585 participants). RA was biopsied intraoperatively in 40 studies (67%), followed by quadriceps (26%; percutaneous biopsy) and other muscles (7%). Cancer site and stage, % of male participants, and age were highly variable between studies. Details regarding patient medical history and biopsy procedures were frequently absent. Lack of description of the population(s) sampled and low sample size contributed to low quality and risk of bias. Weight-losing cases were compared with weight stable cancer or healthy controls without considering a measure of muscle mass in 21 out of 44 studies. In the cohort of patients providing biopsy for this study, 78% of patients had preoperative CT scans and a high proportion (64%) met published criteria for sarcopenia. Fibre type distribution in RA was type I (46% ± 13), hybrid type I/IIA (1% ± 1), type IIA (36% ± 10), hybrid type IIA/D (15% ± 14), and type IID (2% ± 5). Sexual dimorphism was prominent in RA CT cross-sectional area, mean fibre cross-sectional area, and in expression of genes associated with muscle growth, apoptosis, and inflammation (P < 0.05). Medical history revealed multiple co-morbid conditions and medications.

CONCLUSIONS

Continued collaboration between researchers and cancer surgeons enables a more complete understanding of mechanisms of cancer-associated muscle atrophy. Standardization of biobanking practices, tissue manipulation, patient characterization, and classification will enhance the consistency, reliability, and comparability of future studies.

Human Breast Cancer Xenograft Model Implicates Peroxisome Proliferator-activated Receptor Signaling as Driver of Cancer-induced Muscle Fatigue

PURPOSE

This study tested the hypothesis that a patient-derived orthotopic xenograft (PDOX) model would recapitulate the common clinical phenomenon of breast cancer-induced skeletal muscle (SkM) fatigue in the absence of muscle wasting. This study additionally sought to identify drivers of this condition to facilitate the development of therapeutic agents for patients with breast cancer experiencing muscle fatigue.

EXPERIMENTAL DESIGN

Eight female BC-PDOX-bearing mice were produced via transplantation of tumor tissue from 8 female patients with breast cancer. Individual hind limb muscles from BC-PDOX mice were isolated at euthanasia for RNA-sequencing, gene and protein analyses, and an ex vivo muscle contraction protocol to quantify tumor-induced aberrations in SkM function. Differentially expressed genes (DEG) in the BC-PDOX mice relative to control mice were identified using DESeq2, and multiple bioinformatics platforms were employed to contextualize the DEGs.

RESULTS

We found that SkM from BC-PDOX-bearing mice showed greater fatigability than control mice, despite no differences in absolute muscle mass. PPAR, mTOR, IL6, IL1, and several other signaling pathways were implicated in the transcriptional changes observed in the BC-PDOX SkM. Moreover, 3 independent in silico analyses identified PPAR signaling as highly dysregulated in the SkM of both BC-PDOX-bearing mice and human patients with early-stage nonmetastatic breast cancer.

CONCLUSIONS

Collectively, these data demonstrate that the BC-PDOX model recapitulates the expected breast cancer-induced SkM fatigue and further identify aberrant PPAR signaling as an integral factor in the pathology of this condition.

Understanding sex differences in the regulation of cancer-induced muscle wasting

PURPOSE OF REVIEW

We highlight evidence for sexual dimorphism in preclinical and clinical studies investigating the cause and treatment of cancer cachexia.

RECENT FINDINGS

Cancer cachexia is unintended bodyweight loss occurring with cancer, and skeletal muscle wasting is a critical predictor of negative outcomes in the cancer patient. Skeletal muscle exhibits sexual dimorphism in fiber type, function, and regeneration capacity. Sex differences have been implicated in skeletal muscle metabolism, mitochondrial function, immune response to injury, and myogenic stem cell regulation. All of these processes have the potential to be involved in cancer-induced muscle wasting. Unfortunately, the vast majority of published studies examining cancer cachexia in preclinical models or cancer patients either have not accounted for sex in their design or have exclusively studied males. Preclinical studies have established that ovarian function and estradiol can affect skeletal muscle function, metabolism and mass; ovarian function has also been implicated in the sensitivity of circulating inflammatory cytokines and the progression of cachexia.

SUMMARY

Females and males have unique characteristics that effect skeletal muscle's microenvironment and intrinsic signaling. These differences provide a strong rationale for distinct causes for cancer cachexia development and treatment in males and females.

Knockdown of anti-silencing function 1B histone chaperone induces cell apoptosis via repressing PI3K/Akt pathway in prostate cancer

Prostate cancer (PCa) is one of the most common malignancies among males worldwide. Anti-silencing function 1B histone chaperone (ASF1B) has been reported to be involved in PCa. The present study aimed to investigate the role and molecular mechanism of ASF1B in PCa. Data of genes were obtained from The Cancer Genome Atlas data- base. The core gene was identified using the DAVID website. Cell viability and colony formation were detected using a cell counting kit-8 assay and crystal violet staining, respectively. Cell cycle distribution and apoptosis were assessed using flow cytometry analysis. The corresponding factors were analyzed by reverse transcription-quantitative polymerase chain reaction and western blotting. It was demonstrated that ASF1B was highly expressed in the PCa tissues and cells compared with the non-PCa tissues and cells, respectively. While siRNA-ASF1B significantly reduced the viability and colony formation, it promoted apoptosis, G1 phase cell cycle arrest of LNCap as well as C4-2 cells. siRNA-ASF1B was revealed to significantly reduce the level of B-cell lymphoma-2 and cyclin D1, and enhance the expression levels of p53, caspase-3 and Bcl-2 associated X protein. Furthermore, the phosphorylation levels of phosphatidylinositol 3 kinase (PI3K) and protein kinase B (Akt) were significantly decreased in the siRNA-ASF1B group compared with the mock group. In summary, the present study demonstrated that silencing of ASF1B suppressed the proliferation, and promoted apoptosis and cell cycle arrest of PCa cells. Inhibition of the PI3K/Akt signaling pathway was pertinent to the role of si-ASF1B. This phenomenon suggests that the downregulation of ASF1B may aid in inhibiting the progression of PCa.

Dysregulation of metabolic-associated pathways in muscle of breast cancer patients: preclinical evaluation of interleukin-15 targeting fatigue

BACKGROUND

Breast cancer patients report a perception of increased muscle fatigue, which can persist following surgery and standardized therapies. In a clinical experiment, we tested the hypothesis that pathways regulating skeletal muscle fatigue are down-regulated in skeletal muscle of breast cancer patients and that different muscle gene expression patterns exist between breast tumour subtypes. In a preclinical study, we tested the hypothesis that mammary tumour growth in mice induces skeletal muscle fatigue and that overexpression of the cytokine interleukin-15 (IL-15) can attenuate mammary tumour-induced muscle fatigue.

METHODS

Early stage non-metastatic female breast cancer patients (n = 14) and female non-cancer patients (n = 6) provided a muscle biopsy of the pectoralis major muscle during mastectomy, lumpectomy, or breast reconstruction surgeries. The breast cancer patients were diagnosed with either luminal (ER⁺ /PR⁺ , n = 6), triple positive (ER⁺ /PR⁺ /Her2/neu⁺ , n = 5), or triple negative (ER^- /PR^- /Her2/neu^- , n = 3) breast tumours and were being treated with curative intent either with neoadjuvant chemotherapy followed by surgery or surgery followed by standard post-operative therapy. Biopsies were used for RNA-sequencing to compare the skeletal muscle gene expression patterns between breast cancer patients and non-cancer patients. The C57BL/6 mouse syngeneic mammary tumour cell line, E0771, was used to induce mammary tumours in immunocompetent mice, and isometric muscle contractile properties and fatigue properties were analysed following 4 weeks of tumour growth.

RESULTS

RNA-sequencing and subsequent bioinformatics analyses revealed a dysregulation of canonical pathways involved in oxidative phosphorylation, mitochondrial dysfunction, peroxisome proliferator-activated receptor signalling and activation, and IL-15 signalling and production. In a preclinical mouse model of breast cancer, the rate of muscle fatigue was greater in mice exposed to mammary tumour growth for 4 weeks, and this greater muscle fatigue was attenuated in transgenic mice that overexpressed the cytokine IL-15.

CONCLUSIONS

Our data identify novel genes and pathways dysregulated in the muscles of breast cancer patients with early stage non-metastatic disease, with particularly aberrant expression among genes that would predispose these patients to greater muscle fatigue. Furthermore, we demonstrate that IL-15 overexpression can attenuate muscle fatigue associated with mammary tumour growth in a preclinical mouse model of breast cancer. Therefore, we propose that skeletal muscle fatigue is an inherent consequence of breast tumour growth, and this greater fatigue can be targeted therapeutically.