Monitoring Metastasis and Cachexia in a Patient with Breast Cancer: A Case Study

CCL2 signaling promotes skeletal muscle wasting in non-tumor and breast tumor models

Despite advancements in treatment, approximately 25% of patients with breast cancer experience long-term skeletal muscle wasting (SMW), which limits mobility, reduces drug tolerance and adversely impacts survival. By understanding the underlying molecular mechanisms of SMW, we may be able to develop new strategies to alleviate this condition and improve the lives of patients with breast cancer. Chemokines are small soluble factors that regulate homing of immune cells to tissues during inflammation. In breast cancers, overexpression of C-C chemokine ligand 2 (CCL2) correlates with unfavorable prognosis. Elevated levels of CCL2 in peripheral blood indicate possible systemic effects of this chemokine in patients with breast cancer. Here, we investigated the role of CCL2 signaling on SMW in tumor and non-tumor contexts. In vitro, increasing concentrations of CCL2 inhibited myoblast and myotube function through C-C chemokine receptor 2 (CCR2)-dependent mechanisms involving JNK, SMAD3 and AMPK signaling. In healthy mice, delivery of recombinant CCL2 protein promoted SMW in a dose-dependent manner. In vivo knockdown of breast tumor-derived CCL2 partially protected against SMW. Overall, chronic, upregulated CCL2-CCR2 signaling positively regulates SMW, with implications for therapeutic targeting.

Metastatic or xenograft colorectal cancer models induce divergent anabolic deficits and expression of pro-inflammatory effectors of muscle wasting in a tumor-type-dependent manner

We investigated the impact of tumor burden on muscle wasting in metastatic (m) and xenograft (x) models of colorectal cancer (CRC). Male Nod SCID γ and CD2F1 mice were injected subcutaneously or intrasplenically with HCT116 or C26 tumor cells, respectively. CRC tumors resulted in significant muscle wasting regardless of tumor type or model, although muscle loss was exacerbated in mHCT116 hosts. The mHCT116 model decreased ribosomal (r)RNA content and rDNA transcription, whereas the mC26 model showed no loss of rRNA and the upregulation of rDNA transcription. The xHCT116 model reduced mTOR, RPS6, and 4E-BP1 phosphorylation, whereas the mHCT116 model had a similar effect on RPS6 and 4E-BP1 without altering mTOR phosphorylation. The C26 models caused a reduction in 4E-BP1 phosphorylation independent of mTOR. Muscle interleukin (IL)-6 mRNA was elevated in all models except xHCT116, and the NOD-, LRR-, and pyrin domain-containing protein 3 (NLRP3) mRNA was induced only in the mC26 model. IL-1β mRNA increased in all groups with greater expression in metastatic relative to the xenograft model regardless of tumor types. Our findings indicate that HCT116 tumor burden results in more drastic muscle wasting and anabolic deficits, whereas C26 tumor burden causes similar muscle wasting but exhibits a divergent proinflammatory phenotype. These results highlight potentially important divergence in the pathogenesis of muscle wasting among preclinical models of CRC and demonstrate that tumor burden plays a role in determining anabolic deficits and the expression of proinflammatory effectors of muscle wasting in a tumor-type-dependent manner.NEW & NOTEWORTHY We provide evidence demonstrating that colorectal tumor burden plays a role in determining anabolic deficits and the expression of proinflammatory effectors of muscle wasting in a tumor-type-dependent manner.

Adherence to Mediterranean Diet and Nutritional Status in Women with Breast Cancer: What Is Their Impact on Disease Progression and Recurrence-Free Patients' Survival?

Introduction: Nutritional status impacts the survival of patients with cancer. There are few studies that investigate the role of nutritional status on breast cancer survival in women with breast cancer, and even fewer regarding the impact of adhering to the Mediterranean diet (MD). The present study aims to assess the nutritional status, MD adherence, physical activity levels and health-related quality of life (HRQOL) in women diagnosed with breast cancer and evaluate these parameters regarding recurrence-free survival. Methods: A total of 114 women, aged 35-87 years old, diagnosed with breast cancer in Larissa, Greece, participated in the study. Tumor histopathology was reported, and anthropometric indices were measured by a trained nurse, while questionnaires regarding nutritional status (via mini nutritional assessment), HRQOL via EORTC QLQ-C30, physical activity levels via IPAQ and Mediterranean diet adherence via MedDietScore were administered. The participants were followed-up for a maximum time interval of 42 months or until recurrence occurred. Results: A total of 74% of patients were overweight or obese, while 4% of women were undernourished, and 28% were at risk of malnutrition. After 42 months of follow-up, 22 patients (19.3%) had relapsed. The median time to recurrence was 38 months (IQR: 33-40 months) and ranged between 23 to 42 months. Higher levels of MD adherence were significantly associated with lower body mass index (BMI) values, earlier disease stage, smaller tumor size, absence of lymph node metastases and better physical activity levels (p < 0.05). Normal nutritional status was significantly associated with higher BMI values and better health-related quality of life (p ≤ 0.05). In univariate analysis, patients with higher levels of MD adherence and well-nourished patients had significantly longer recurrence-free survival (p < 0.05). In multivariate analysis, MD adherence and nutritional status were independently associated with recurrence-free patients' survival after adjustment for several confounding factors (p < 0.05). Conclusions: The impact of MD on time to recurrence is still under investigation, and future interventional studies need to focus on the role of adhering to the MD before and after therapy in survival and breast cancer progression. Furthermore, the present study also highlights the importance of an adequate nutritional status on disease progression, and the need for nutritional assessment, education and intervention in women with breast cancer.

Prognostic significance of the skeletal muscle index and systemic inflammatory index in patients with lymph node-positive breast cancer after radical mastectomy

Background

The role of skeletal muscle index (SMI) and systemic inflammation index (SII) for patients with lymph node-positive breast cancer remain controversial. This retrospective study aims to evaluate the individual and synergistic value of SMI and SII in outcomes prediction in this population.

Methods

Lymph node-positive breast cancer patients who received mastectomy between January 2011 and February 2013 were included in this retrospective study. We used abdominal computed tomography (CT) to measure skeletal muscle mass at the third lumbar (L3) level. The optimal cut-off values of SMI and SII were determined through maximizing the Youden index on the receiver operating characteristic (ROC) curves. Kaplan–Meier method was used to assess the correlation between SMI, SII, and overall survival (OS). The prognostic value of SMI and SII were analyzed with the multivariable Cox proportional hazards model.

Results

Of 97 patients included in our study (mean age: 46 [range: 27–73] years; median follow-up: 62.5 months), 71 had low SMI (sarcopenia), 59 had low SII, and 56 had low SMI + SII. Kaplan–Meier survival curves showed that both high SMI (P = 0.021, 5-year OS: 84.0% vs. 94.1%) and high SII (P = 0.043, 5-year OS: 81.0% vs. 97.3%) were associated with worse OS. Additionally, patients with either low SMI or low SII had significantly better OS (P = 0.0059, 5-year OS: 100.0% vs. 84.6%) than those with high SMI + SII. Multivariable analysis confirmed the predictive values of high SMI (P = 0.024, hazard ratio [HR]: 9.87) and high SII (P = 0.048, HR: 6.87) for poor OS. Moreover, high SMI + SII was significantly associated with poor survival (P = 0.016, HR: 16.36).

Conclusions

In this retrospective analysis, both SMI and SII independently predicted the prognosis of patients with lymph node-positive breast cancer. SMI + SII might be a stronger prognostic factor than either alone based on our findings, but should be further verified in a larger study.

Contribution of adrenergic mechanisms for the stress-induced breast cancer carcinogenesis

Breast cancer is the most common and deadliest type of cancer in women. Stress exposure has been associated with carcinogenesis and the stress released neurotransmitters, noradrenaline and adrenaline, and their cognate receptors, can participate in the carcinogenesis process, either by regulating tumor microenvironment or by promoting systemic changes. This work intends to provide an overview of the research done in this area and try to unravel the role of adrenergic ligands in the context of breast carcinogenesis. In the initiation phase, adrenergic signaling may favor neoplastic transformation of breast epithelial cells whereas, during cancer progression, may favor the metastatic potential of breast cancer cells. Additionally, adrenergic signaling can alter the function and activity of other cells present in the tumor microenvironment towards a protumor phenotype, namely macrophages, fibroblasts, and by altering adipocyte's function. Adrenergic signaling also promotes angiogenesis and lymphangiogenesis and, systemically, may induce the formation of preneoplastic niches, cancer-associated cachexia and alterations in the immune system which contribute for the loss of quality of life of breast cancer patients and their capacity to fight cancer. Most studies points to a major contribution of β₂ -adrenoceptor activated pathways on these effects. The current knowledge of the mechanistic pathways activated by β₂ -adrenoceptors in physiology and pathophysiology, the availability of selective drugs approved for clinical use and a deeper knowledge of the basic cellular and molecular pathways by which adrenergic stimulation may influence cancer initiation and progression, opens the possibility to use new therapeutic alternatives to improve efficacy of breast cancer treatments.

Physiologic and molecular characterization of a novel murine model of metastatic head and neck cancer cachexia

BACKGROUND

Cancer cachexia is a metabolic disorder characterized by the progressive loss of fat and lean mass that results in significant wasting, ultimately leading to reduced quality of life and increased mortality. Effective therapies for cachexia are lacking, potentially owing to the mismatch in clinically relevant models of cachexia. Specifically, cachexia observed in a clinical setting is commonly associated with advanced or late-stage cancers that are metastatic, yet pre-clinical metastatic models of cachexia are limited. Furthermore, the prevalence of cachexia in head and neck cancer patients is high, yet few pre-clinical models of head and neck cancer cachexia exist. In addition to these shortcomings, cachexia is also heterogeneous among any given cancer, whereas patients with similar disease burden may experience significantly different degrees of cachexia symptoms. In order to address these issues, we characterize a metastatic model of human papilloma virus (HPV) positive head and neck squamous cell carcinoma that recapitulates the cardinal clinical and molecular features of cancer cachexia.

METHODS

Male and female C57BL/6 mice were implanted subcutaneously with oropharyngeal squamous cell carcinoma cells stably transformed with HPV16 E6 and E7 together with hRas and luciferase (mEERL) that metastasizes to the lungs (MLM). We then robustly characterize the physiologic, behavioural, and molecular signatures during tumour development in two MLM subclones.

RESULTS

Mice injected with MLM tumour cells rapidly developed primary tumours and eventual metastatic lesions to the lungs. MLM3, but not MLM5, engrafted mice progressively lost fat and lean mass during tumour development despite the absence of anorexia (P < 0.05). Behaviourally, MLM3-implanted mice displayed decreased locomotor behaviours and impaired nest building (P < 0.05). Muscle catabolism programmes associated with cachexia, including E3 ubiquitin ligase and autophagy up-regulation, along with progressive adipose wasting and accompanying browning gene signatures, were observed. Tumour progression also corresponded with hypothalamic and peripheral organ inflammation, as well as an elevation in neutrophil-to-lymphocyte ratio (P < 0.05). Finally, we characterize the fat and lean mass sparing effects of voluntary wheel running on MLM3 cachexia (P < 0.05).

CONCLUSIONS

This syngeneic MLM3 allograft model of metastatic cancer cachexia is reliable, consistent, and readily recapitulates key clinical and molecular features and heterogeneity of cancer cachexia. Because few metastatic models of cachexia exist-even though cachexia often accompanies metastatic progression-we believe this model more accurately captures cancer cachexia observed in a clinical setting and thus is well suited for future mechanistic studies and pre-clinical therapy development for this crippling metabolic disorder.

Tumor-derived MMPs regulate cachexia in a Drosophila cancer model

Cachexia, the wasting syndrome commonly observed in advanced cancer patients, accounts for up to one-third of cancer-related mortalities. We have established a Drosophila larval model of organ wasting whereby epithelial overgrowth in eye-antennal discs leads to wasting of the adipose tissue and muscles. The wasting is associated with fat-body remodeling and muscle detachment and is dependent on tumor-secreted matrix metalloproteinase 1 (Mmp1). Mmp1 can both modulate TGFβ signaling in the fat body and disrupt basement membrane (BM)/extracellular matrix (ECM) protein localization in both the fat body and the muscle. Inhibition of TGFβ signaling or Mmps in the fat body/muscle using a QF2-QUAS binary expression system rescues muscle wasting in the presence of tumor. Altogether, our study proposes that tumor-derived Mmps are central mediators of organ wasting in cancer cachexia.

Gut Microbiota as a Positive Potential Therapeutic Factor in Carcinogenesis: an Overview of Microbiota-Targeted Therapy

Cancer therapeutic methods comprising chemotherapy, radiotherapy, and surgery are so routine in cancer treatment. Remarkably, there are several personal features which affect the effectiveness of such treatments including nutrition, microbiome diversity, and physical activity which has distinct significant roles during and after therapies along with their bilateral connections. In this way, the ability of gut microbiota36 in modulating the efficacy of chemotherapeutic medications in cancer and other types of disorders is of great importance. In addition, the role of dietary, probiotic, and synthetically engineered bacteria in manipulating and optimizing the gut microbiota is of interest. Conspicuously, the correlation between the commensal microbiota and also host can regulate the physiological activities comprising the immunity system and inflammatory agents and it is scanned in the category of cancers. Bacterial species have been employed in cancer therapy; commensal microbes posse a key beneficial role in this field. Practically, the microbiota has this potential to accelerate and modulates a certain response by priming in order to release the pro-inflammatory agents. We would like to discuss these vital factors in this review as gut microbiota has the potential to be the main option for personalized cancer treatment strategies in the future. Meaning, this novel data present clinical promising feasibilities of modulating cancer therapy with using microbiota.

Advanced breast cancer with cachexia: A case report

RATIONALE

Cachexia is a clinically relevant syndrome in cancer that is associated with reduced tolerance to anticancer therapy, reduced quality of life, and reduced survival rates. Cachexia is most prevalent in pancreatic, gastric, colorectal, lung, and head and neck cancers. It is rarely documented in breast cancer patients.

PATIENT CONCERNS

In our case report of a breast cancer patient with bone metastasis who was monitored throughout the course of her treatment, we document the development of cachexia using image analyses in relation to her metastatic burden. In the 2-year period, from April 10, 2015, to February 09, 2017, she lost 16% of her baseline weight. During this time, she was repeatedly hospitalized for chest tightness, edema of both lower limbs, numbness and pain in the left lower extremity and backache.

DIAGNOSES

Our patient was a 46-year-old premenopausal woman when she was firstly diagnosed. Several years after surgery for invasive ductal carcinoma of the left breast, she had multiple systemic bone metastases (the thoracic spine, the ribs, etc), lung metastasis, bilateral axillary lymph node metastasis, and metastasis of the right neck lymph node in IV area.

INTERVENTIONS

The patient completed 6 cycles of postoperative adjuvant chemotherapy and long-term endocrine therapy after a radical mastectomy for breast cancer. During the fourth progression, 6 cycles of rescue chemotherapy were performed. Local lumbosacral radiotherapy, and lumbar surgery were carried out to relieve symptoms after several progressions.

OUTCOMES

She became extremely thin, weighing only 50 kg at admission on July 23, 2018. This eventually led to multiple organ failure and death.

LESSONS

We noted a strong negative correlation between the abdominal muscle area and the metastatic tumor area at the second lumbar vertebral (L2) level. The monitoring of abdominal muscle wasting may serve as a marker, and therefore a prognostic factor, for both cachexia and the extent of metastatic disease. This is especially true with breast cancer, where metastasis to bone is frequent. Our data from a computational tomography radiological quantification, may provide clinicians with early indications of the extent of cachexia in metastatic breast cancer patients.

Low Subcutaneous Adiposity and Mortality in Esophageal Cancer

BACKGROUND

Recent data suggest that subcutaneous adiposity represents an independent prognostic marker in cancer. We aimed to determine whether subcutaneous adiposity estimated by the subcutaneous adiposity tissue index (SATI) was associated with mortality in esophageal cancer.

METHODS

We conducted a retrospective analysis of a prospectively enrolled cohort from 2009 to 2015 with esophageal cancer at two major cancer centers. CT scans for initial staging were used to quantify adiposity and skeletal muscle areas. Subjects were categorized as above or below median SATI using sex-specific values. Sarcopenia was defined using previously established skeletal muscle area cutoffs. Cox proportional hazards modeling was performed to determine associations between SATI and all-cause mortality.

RESULTS

Of the original 167 patients, 78 met inclusion criteria and had CT images available. Mean age was 67 years, 81.8% had adenocarcinoma, and 58.9% had stage 3 or 4 disease. Median follow-up time was 29.5 months. Overall 5-year survival was 38.9% [95% confidence interval (CI), 26.8-50.7]. Lower body mass index, higher Charlson comorbidity score, and more advanced stage were independently associated with low SATI. Patients with low SATI had increased mortality (unadjusted HR 2.23; 95% CI, 1.20-4.12), even when adjusted for sarcopenia or for percent weight loss. In a multivariable model including age, histology, stage, and receipt of curative surgery, the association between low SATI and mortality was attenuated (adjusted HR 1.64; 95% CI, 0.81-3.34).

CONCLUSIONS

Low subcutaneous adiposity as estimated by SATI may be associated with increased mortality in esophageal cancer.

IMPACT

Interventions to reduce loss of subcutaneous fat may improve survival in esophageal cancer.

Impact of BMI on the outcome of metastatic breast cancer patients treated with everolimus: a retrospective exploratory analysis of the BALLET study

INTRODUCTION

Reliable biomarkers of response to mTOR inhibition are yet to be identified. As mTOR is heavily implicated in cell-metabolism, we investigated the relation between BMI variation and outcomes in metastatic breast cancer (mBC) patients treated with everolimus.

RESULTS

we found a linear correlation between everolimus exposure duration and BMI/weight decrease. Patients exhibiting >2 kg weight loss or >3% BMI decrease from baseline at the end of treatment (EOT) had a statistically significant improvement in PFS. Interestingly, a similar BMI/weight decrease within the first 8 weeks of therapy identified patients at higher risk of progression.

PATIENTS AND METHODS

we performed a retrospective analysis of patients enrolled in the BALLET trial who progressed during the study. Primary end-point was progression-free survival (PFS). Secondary end-point was the identification of other predictors of response.

CONCLUSION

A >3% weight loss at EOT is associated with better outcome in mBC patients treated with everolimus. On the contrary, a significant early weight loss represents a predictor of poor survival and could therefore be used as an early negative prognostic marker. As PI3K-inhibition also converges onto mTOR, these findings might extend to patients treated with selective PI3K inhibitors and warrant further investigation.

Systemic Actions of Breast Cancer Facilitate Functional Limitations

Breast cancer is a disease of a specific organ, but its effects are felt throughout the body. The systemic effects of breast cancer can lead to functional limitations in patients who suffer from muscle weakness, fatigue, pain, fibromyalgia, or many other dysfunctions, which hasten cancer-associated death. Mechanistic studies have identified quite a few molecular defects in skeletal muscles that are associated with functional limitations in breast cancer. These include circulating cytokines such as TNF-α, IL-1, IL-6, and TGF-β altering the levels or function of myogenic molecules including PAX7, MyoD, and microRNAs through transcriptional regulators such as NF-κB, STAT3, and SMADs. Molecular defects in breast cancer may also include reduced muscle mitochondrial content and increased extracellular matrix deposition leading to energy imbalance and skeletal muscle fibrosis. This review highlights recent evidence that breast cancer-associated molecular defects mechanistically contribute to functional limitations and further provides insights into therapeutic interventions in managing functional limitations, which in turn may help to improve quality of life in breast cancer patients.

Metastasis and cachexia: alongside in clinics, but not so in animal models

Cancer cachexia is a paraneoplastic syndrome characterized by lean mass wasting (with or without fat mass decrease), culminating in involuntary weight loss, which is the key clinical observation nowadays. There is a notable lack of studies involving animal models to mimic the clinical reality, which are mostly patients with cachexia and metastatic disease. This mismatch between the clinical reality and animal models could at least partly contribute to the poor translation observed in the field. In this paper, we retrieved and compared animal models used for cachexia research from 2017 and 10 years earlier (2007) and observed that very little has changed. Especially, clinically relevant models where cachexia is studied in an orthotopic or metastatic context were and still are very scarce. Finally, we described and supported the biological rationale behind why, despite technical challenges, these two phenomena-metastasis and cachexia-should be modelled in parallel, highlighting the overlapping pathways between them. To sum up, this review aims to contribute to rethinking and possibly switching the models currently used for cachexia research, to hopefully obtain better and more translational outcomes.

Chemotherapy-induced loss of bone and muscle mass in a mouse model of breast cancer bone metastases and cachexia

BACKGROUND

Chemotherapy used to treat malignancy can lead to loss of skeletal muscle mass and reduced force production, and can reduce bone volume in mice. We have shown that bone-muscle crosstalk is a key nexus in skeletal muscle function and bone homeostasis in osteolytic breast cancer bone metastases. Because chemotherapy has significant negative side effects on bone mass, and because bone loss can drive skeletal muscle weakness, we have examined the effects of chemotherapy on the musculoskeletal system in mice with breast cancer bone metastases.

METHODS AND RESULTS

Six-week-old Female athymic nude mice were inoculated with 10⁵ MDA-MB231 human breast cancer cells into the left ventricle and bone metastases were confirmed by X-ray. Mice were injected with carboplatin at a dose of 60mg/kg once per week starting 4 days after tumor inoculation. Skeletal muscle was collected for biochemical analysis and extensor digitorum longus (EDL) whole muscle contractility was measured. The femur and tibia bone parameters were assessed by microCT and tumor burden in bone was determined by histology. Healthy mice treated with carboplatin lose whole body weight and have reduced individual muscle weights (gastrocnemius, tibialis anterior (TA), and EDL), reduced trabecular bone volume (BV/TV), and reduced EDL function. Mice with MDA-MB-231 bone metastases treated with carboplatin lose body weight, and have reduced EDL function as healthy mice treated with carboplatin. Mice with MDA-MB-231 bone metastases plus carboplatin do have reduced proximal tibia BV/TV compared to carboplatin alone, but carboplatin does reduce tumor burden in bone.

CONCLUSIONS

Our data shows that carboplatin treatment, aimed at reducing tumor burden, contributes to cachexia and trabecular bone loss. The muscle atrophy and weakness may occur through bone-muscle crosstalk and would lead to a feed-forward cycle of musculoskeletal degradation. Despite anti-tumor effects of chemotherapy, musculoskeletal impairment is still significant in mice with bone metastases.

Updates on the pathogenesis of advanced lung cancer-induced cachexia

Advanced lung cancer is becoming a chronic disease threatening human life and health. Cachexia has been recognized as the most common problem associated with advanced lung cancer. Lung cancer‐induced cachexia seriously affects patients’ quality of life. The present article summarizes the pathogenesis of advanced lung cancer‐induced cachexia from three aspects: anorexia, cytokines, and energy and metabolic abnormalities. In addition, the present article proposes corresponding nursing measures based on cachexia pathogenesis to improve the quality of life and survival rate of cachectic patients with advanced lung cancer by combining continuously advancing treatment regimens and effective nursing. The present article also provides references for healthcare professionals when administering related treatments and nursing care.

The Role of Systemic Inflammation in Cancer-Associated Muscle Wasting and Rationale for Exercise as a Therapeutic Intervention

Progressive skeletal muscle wasting in cancer cachexia involves a process of dysregulated protein synthesis and breakdown.  This catabolism may be the result of mal-nutrition, and an upregulation of both pro-inflammatory cytokines and the ubiquitin proteasome pathway (UPP), which can subsequently increase myostatin and activin A release.  The skeletal muscle wasting associated with cancer cachexia is clinically significant, it can contribute to treatment toxicity or the premature discontinuation of treatments resulting in increases in morbidity and mortality.  Thus, there is a need for further investigation into the pathophysiology of muscle wasting in cancer cachexia to develop effective prophylactic and therapeutic interventions.  Several studies have identified a central role for chronic-systemic inflammation in initiating and perpetuating muscle wasting in patients with cancer.  Interestingly, while exercise has shown efficacy in improving muscle quality, only recently have investigators begun to assess the impact that exercise has on chronic-systemic inflammation.  To put this new information into context with established paradigms, here we review several biological pathways (e.g. dysfunctional inflammatory response, hypothalamus pituitary adrenal axis, and increased myostatin/activin A activity) that may be responsible for the muscle wasting in patients with cancer.  Additionally, we discuss the potential impact that exercise has on these pathways in the treatment of cancer cachexia.  Exercise is an attractive intervention for muscle wasting in this population, partially because it disrupts chronic-systemic inflammation mediated catabolism.  Most importantly, exercise is a potent stimulator of muscle synthesis, and therefore this therapy may reverse muscle damage caused by cancer cachexia. 

The Role of Systemic Inflammation in Cancer-Associated Muscle Wasting and Rationale for Exercise as a Therapeutic Intervention

Progressive skeletal muscle wasting in cancer cachexia involves a process of dysregulated protein synthesis and breakdown. This catabolism may be the result of mal-nutrition, and an upregulation of both pro-inflammatory cytokines and the ubiquitin proteasome pathway (UPP), which can subsequently increase myostatin and activin A release. The skeletal muscle wasting associated with cancer cachexia is clinically significant, it can contribute to treatment toxicity or the premature discontinuation of treatments resulting in increases in morbidity and mortality. Thus, there is a need for further investigation into the pathophysiology of muscle wasting in cancer cachexia to develop effective prophylactic and therapeutic interventions. Several studies have identified a central role for chronic-systemic inflammation in initiating and perpetuating muscle wasting in patients with cancer. Interestingly, while exercise has shown efficacy in improving muscle quality, only recently have investigators begun to assess the impact that exercise has on chronic-systemic inflammation. To put this new information into context with established paradigms, here we review several biological pathways (e.g. dysfunctional inflammatory response, hypothalamus pituitary adrenal axis, and increased myostatin/activin A activity) that may be responsible for the muscle wasting in patients with cancer. Additionally, we discuss the potential impact that exercise has on these pathways in the treatment of cancer-related muscle wasting. Exercise is an attractive intervention for muscle wasting in this population, partially because it disrupts chronic-systemic inflammation mediated catabolism. Most importantly, exercise is a potent stimulator of muscle synthesis, and therefore this therapy may reverse muscle damage caused by cancer cachexia.

Effects of Serum Leptin and Resistin Levels on Cancer Cachexia in Patients With Advanced-Stage Non-Small Cell Lung Cancer

INTRODUCTION

Cancer cachexia is one of the most frequent effects of malignancy, is often associated with poor prognosis, and may account for up to 20% of cancer deaths. The aim of our study was to evaluate the relationship of cancer cachexia and serum levels of resistin and leptin in patients with advanced non-small cell lung cancer.

METHODS

A total of 67 chemotherapy-naïve patients with advanced-stage non-small cell cancer and a control group containing 20 healthy individuals without a known chronic disease were enrolled in this study. All individuals in the control group were age and sex matched. Demographic, anthropometric, laboratory data and serum levels of adipokines were measured for 2 groups. Progression-free survival and overall survival were estimated using the Kaplan-Meier method. Survival among various factors was calculated using the log-rank test.

RESULTS

Patients presented significantly higher serum resistin (P = .0001) and lower serum leptin levels (P = .025) than the control group. Lower serum levels of leptin were correlated with overall survival (P = .011).

CONCLUSIONS

Serum leptin and resistin levels play key role as proinflammatory cytokines in lung cancer and cancer cachexia; however, their use as diagnostic or prognostic markers is not possible yet, and further large-scale studies are required to confirm our findings.

Metabolic Changes During Cancer Cachexia Pathogenesis

Wasting of adipose tissue and skeletal muscle is a hallmark of metastatic cancer and a major cause of death. Like patients with cachexia caused by other chronic infections or inflammatory diseases, the cancer subject manifests both malnutrition and metabolic stress. Both carbohydrate utilization and amino acid incorporation are decreased in the muscles of cancer cachexia patients. Cancer cells affect host metabolism in two ways: (a) their own metabolism of nutrients into other metabolites and (b) circulating factors they secrete or induce the host to secrete. Accelerated glycolysis and lactate production, i.e., the Warburg effect and the resultant increase in Cori cycle activity, are the most widely discussed metabolic effects. Meanwhile, although a large number of pro-cachexia circulating factors have been found, such as TNFa, IL-6, myostatin, and PTHrp, none have been shown to be a dominant factor that can be targeted singly to treat cancer cachexia in humans. It is possible that given the complex multifactorial nature of the cachexia secretome, and the personalized differences between cancer patients, targeting any single circulating factor would always be insufficient to treat cachexia for all patients. Here we review the metabolic changes that occur in response to tumor growth and tumor-secreted factors during cachexia.