Cancer cachexia: involvement of an expanding macroenvironment

Involvement of the gut microbiota in cancer cachexia

Cancer cachexia, or the unintentional loss of body weight in patients with cancer, is a multiorgan and multifactorial syndrome with a complex and largely unknown etiology; however, metabolic dysfunction and inflammation remain hallmarks of cancer-associated wasting. Although cachexia manifests with muscle and adipose tissue loss, perturbations to the gastrointestinal tract may serve as the frontline for both impaired nutrient absorption and immune-activating gut dysbiosis. Investigations into the gut microbiota have exploded within the past two decades, demonstrating multiple gut-tissue axes; however, the link between adipose and skeletal muscle wasting and the gut microbiota with cancer is only beginning to be understood. Furthermore, the most used anticancer drugs (e.g. chemotherapy and immune checkpoint inhibitors) negatively impact gut homeostasis, potentially exacerbating wasting and contributing to poor patient outcomes and survival. In this review, we 1) highlight our current understanding of the microbial changes that occur with cachexia, 2) discuss how microbial changes may contribute to adipose and skeletal muscle wasting, and 3) outline study design considerations needed when examining the role of the microbiota in cancer-induced cachexia.

Role of the intestinal microbiota in contributing to weight disorders and associated comorbidities

SUMMARYThe gut microbiota is a major factor contributing to the regulation of energy homeostasis and has been linked to both excessive body weight and accumulation of fat mass (i.e., overweight, obesity) or body weight loss, weakness, muscle atrophy, and fat depletion (i.e., cachexia). These syndromes are characterized by multiple metabolic dysfunctions including abnormal regulation of food reward and intake, energy storage, and low-grade inflammation. Given the increasing worldwide prevalence of obesity, cachexia, and associated metabolic disorders, novel therapeutic strategies are needed. Among the different mechanisms explaining how the gut microbiota is capable of influencing host metabolism and energy balance, numerous studies have investigated the complex interactions existing between nutrition, gut microbes, and their metabolites. In this review, we discuss how gut microbes and different microbiota-derived metabolites regulate host metabolism. We describe the role of the gut barrier function in the onset of inflammation in this context. We explore the importance of the gut-to-brain axis in the regulation of energy homeostasis and glucose metabolism but also the key role played by the liver. Finally, we present specific key examples of how using targeted approaches such as prebiotics and probiotics might affect specific metabolites, their signaling pathways, and their interactions with the host and reflect on the challenges to move from bench to bedside.

Characteristics and prognostic impact of cancer cachexia defined by the Asian Working Group for Cachexia consensus in patients with curable gastric cancer

BACKGROUND

Cachexia is prevalent in cancer patients. The conventional diagnostic criteria for cachexia are often based on Western evidence, lacking consensus for Asian populations. This study aims to compare Asian Working Group for Cachexia (AWGC) criteria with Fearon's criteria, assessing their differences in population characteristics and prognostic impact.

METHODS

The clinical data of patients who underwent radical gastrectomy between 2013 and 2019 were prospectively collected. Cachexia diagnosis involves the utilization of either AWGC criteria and the previous international consensus proposed by Fearon et al. A scoring model is established based on the optional criteria according to the AWGC criteria. Univariate and multivariate logistic and Cox regression analysis were conducted to determine the independent effect factors for postoperative complications and overall survival.

RESULTS

In a total of 1330 patients, 461 met AWGC cachexia criteria and 311 met Fearon's criteria. Excluding 262 overlapping cases, those diagnosed solely with AWGC-cachexia had higher age and lower BMI, albumin, hemoglobin, and handgrip strength compared to those by Fearon's criteria alone. AWGC-cachexia independently increased the risk of postoperative complications, whereas Fearon's criteria did not. Patients with AWGC-cachexia also exhibited shorter overall survival than Fearon's criteria. The AWGC-based cachexia grading system effectively stratifies the risks of postoperative complications and mortality.

CONCLUSIONS

The AWGC criteria is more effective in diagnosing cancer cachexia in the Asian population and provide better prognostic indicators.

On-treatment Modified Glasgow Prognostic Score Provides Predictive Information Complementary to Radiological Staging in Metastatic Urothelial Carcinoma on Immunotherapy

In the immunotherapy era it is difficult to predict patient prognosis on the basis of radiological staging alone, especially for the subgroup with stable disease (SD), which encompasses a wide range of clinical outcomes. Thus, there is need for reliable and, ideally, cost-efficient biomarkers to improve the accuracy of outcome prediction. We evaluated the on-treatment modified Glasgow Prognostic Score (mGPS)-a known predictor of outcomes in several cancers that is based on serum C-reactive protein and albumin-in patients with metastatic urothelial carcinoma (mUC) treated with immune checkpoint inhibition (ICI) in the phase 2 IMvigor210 and phase 3 IMvigor211 trials. On-treatment mGPS provides valuable prognostic information complementary to radiological staging, particularly for patients with SD. In IMvigor210, on-treatment mGPS predicts outcomes as early as 6 wk after ICI initiation, considerably before the first routine staging typically performed after 10-12 wk. Our study suggests that on-treatment mGPS complements radiological imaging in predicting outcomes for patients with mUC undergoing ICI. PATIENT SUMMARY: For patients with metastatic bladder cancer receiving immunotherapy, it is difficult to predict treatment outcomes from imaging scans alone. Our study results suggest that a score called the modified Glasgow Prognostic Score based on just two proteins (C-reactive protein and albumin) measured in blood can accurately predict outcomes. Use of the mGPS along with imaging scans may be better in predicting the survival benefit from immunotherapy.

The crosstalk between macrophages and cancer cells potentiates pancreatic cancer cachexia

With limited treatment options, cachexia remains a major challenge for patients with cancer. Characterizing the interplay between tumor cells and the immune microenvironment may help identify potential therapeutic targets for cancer cachexia. Herein, we investigate the critical role of macrophages in potentiating pancreatic cancer induced muscle wasting via promoting TWEAK (TNF-like weak inducer of apoptosis) secretion from the tumor. Specifically, depletion of macrophages reverses muscle degradation induced by tumor cells. Macrophages induce non-autonomous secretion of TWEAK through CCL5/TRAF6/NF-κB pathway. TWEAK promotes muscle atrophy by activating MuRF1 initiated muscle remodeling. Notably, tumor cells recruit and reprogram macrophages via the CCL2/CCR2 axis and disrupting the interplay between macrophages and tumor cells attenuates muscle wasting. Collectively, this study identifies a feedforward loop between pancreatic cancer cells and macrophages, underlying the non-autonomous activation of TWEAK secretion from tumor cells thereby providing promising therapeutic targets for pancreatic cancer cachexia.

Exosomes in the pathogenesis and treatment of cancer-related cachexia

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

Effect of preoperative immunonutrition on postoperative short-term clinical outcomes in patients with gastric cancer cachexia: a prospective randomized controlled trial

BACKGROUND

Although current guidelines(ESPEN guideline: Clinical nutrition in surgery and other guidelines) recommend preoperative immunonutrition for cachectic gastric cancer patients, the strength of the recommendation is weak, and the level of evidence is low. The benefits of preoperative immunonutrition still remain controversial.

PATIENTS AND METHODS

112 patients with gastric cancer cachexia were enrolled in the study and randomly assigned in a 1:1 ratio to receive either preoperative enteral immunonutrition support (IN, n = 56) or standard enteral nutrition support (SEN, n = 56). The primary endpoint was the incidence of infectious complications, and the secondary endpoints included the nutritional indicators, inflammatory markers, immune parameters, postoperative recovery and complications and gastrointestinal intolerance reactions.

RESULTS

The incidence of postoperative infectious complications(P = 0.040) and overall complications (P = 0.049)was significantly lower in the IN group compared to the SEN group. In terms of laboratory inflammatory indexes, patients in the IN group demonstrated significantly lower levels of white blood cells (WBC), C-reactive protein (CRP), and interleukin-6 (IL-6), as well as higher levels of lymphocytes (LYMPH) and immunoglobulin A (IgA), compared to patients in the SEN group, with statistically significant differences. In terms of clinical outcomes, the IN group had a shorter duration of antibiotic use (P = 0.048), shorter hospital stay (P = 0.018), and lower total hospital costs (P = 0.034) compared to the SEN group. The IN group also experienced significantly less weight loss after surgery (P = 0.043).

CONCLUSION

Preoperative administration of immunonutrition formula has a positive impact on the incidence of infectious complications in patients with gastric cancer cachexia after surgery. It improves patients' inflammatory and immune status, shortens hospital stays, and reduces healthcare costs. Preoperative use of immunonutrition may contribute to the improvement of prognosis in this high-risk population.

Embracing cancer complexity: Hallmarks of systemic disease

The last 50 years have witnessed extraordinary developments in understanding mechanisms of carcinogenesis, synthesized as the hallmarks of cancer. Despite this logical framework, our understanding of the molecular basis of systemic manifestations and the underlying causes of cancer-related death remains incomplete. Looking forward, elucidating how tumors interact with distant organs and how multifaceted environmental and physiological parameters impinge on tumors and their hosts will be crucial for advances in preventing and more effectively treating human cancers. In this perspective, we discuss complexities of cancer as a systemic disease, including tumor initiation and promotion, tumor micro- and immune macro-environments, aging, metabolism and obesity, cancer cachexia, circadian rhythms, nervous system interactions, tumor-related thrombosis, and the microbiome. Model systems incorporating human genetic variation will be essential to decipher the mechanistic basis of these phenomena and unravel gene-environment interactions, providing a modern synthesis of molecular oncology that is primed to prevent cancers and improve patient quality of life and cancer outcomes.

Leukemia inhibitory factor suppresses hepatic de novo lipogenesis and induces cachexia in mice

Cancer cachexia is a systemic metabolic syndrome characterized by involuntary weight loss, and muscle and adipose tissue wasting. Mechanisms underlying cachexia remain poorly understood. Leukemia inhibitory factor (LIF), a multi-functional cytokine, has been suggested as a cachexia-inducing factor. In a transgenic mouse model with conditional LIF expression, systemic elevation of LIF induces cachexia. LIF overexpression decreases de novo lipogenesis and disrupts lipid homeostasis in the liver. Liver-specific LIF receptor knockout attenuates LIF-induced cachexia, suggesting that LIF-induced functional changes in the liver contribute to cachexia. Mechanistically, LIF overexpression activates STAT3 to downregulate PPARα, a master regulator of lipid metabolism, leading to the downregulation of a group of PPARα target genes involved in lipogenesis and decreased lipogenesis in the liver. Activating PPARα by fenofibrate, a PPARα agonist, restores lipid homeostasis in the liver and inhibits LIF-induced cachexia. These results provide valuable insights into cachexia, which may help develop strategies to treat cancer cachexia.