Periodic Reporting for period 2 - StopWaste (Targeting the crosstalk of lipid and glucose metabolism to stop cancer-associated wasting)
Reporting period: 2022-11-01 to 2024-04-30
Cachexia is an irreversible metabolic disorder that accompanies many chronic diseases such as chronic heart failure, chronic kidney disease, or chronic obstructive pulmonary disease. Importantly, it is also a critically linked to poor prognosis in cancer. Cachexia leads to involuntary, progressive weight loss that cannot be fully prevented by enhanced energy intake, and a progressive loss or “wasting” of muscle and adipose tissue. In some types of cancer such as pancreatic cancer, up to 80% of the patients suffer from cachexia. The severe loss of body weight, muscle and adipose tissue mass ultimately kills 30% of patients with cancer. Systemic metabolism in cachexia is fundamentally reprogrammed, but neither is it known what causes this maladaptation, nor when the molecular changes that precede cachexia are initiated by the cancer cells. The grand challenge in understanding cachexia is to decipher where energy is lost, causing wasting of the body mass.
With STOPWASTE, I hypothesized that cachexia-inducing cancer cells activate futile energy wasting cycles within and between tissues that drive energy loss, and that result from the fundamental dysbalance of lipid and glucose metabolism. We have identified bioreactive lipid species specific to cachexia that result from alterations in liver lipids and dysregulation of key enzymes of liver lipid metabolism. We found that these lipids contributed to cachexia by influencing muscle and liver metabolism, and could be targeted using the ceramide synthesis inhibitor myriocin. Further connecting lipid and glucose metabolism, using glucose tracing into adipose tissue of cachectic and pre-cachectic mice, we identified substantial differences between cachectic and non-cachectic adipose tissue, particularly an altered flux of fatty acids and amino acids through the tricarboxylic acid cycle (TCA). Dysfunctional adipose tissue metabolism was partially linked to the TCA gatekeeper PDK4.
Both disturbed lipid and glucose metabolism are early events in cachexia development, and impaired glucose metabolism reportedly precedes cachexia in patients with cancer. We report here that patients with disturbed glucose metabolism showed a higher incidence of cachexia associated with pancreatic and colorectal cancers, and weight loss and inflammation were worse when diabetes and cachexia co-existed in these patients. Cachexia induced a strong infiltration of inflammatory cells, mainly macrophages, into islets and the exocrine pancreas of cachectic mice, inducing a phenotype resembling pancretitis, which may explain why the additional metabolic challenge of diabetes is detrimental in cachexia. Overall, STOPWASTE has so far identified novel biomarkers, disease heterogeneity, and tissue-intrinsic mechanisms contributing to the pathogenesis of cancer cachexia.
With STOPWASTE, I hypothesized that cachexia-inducing cancer cells activate futile energy wasting cycles within and between tissues that drive energy loss, and that result from the fundamental dysbalance of lipid and glucose metabolism. We have identified bioreactive lipid species specific to cachexia that result from alterations in liver lipids and dysregulation of key enzymes of liver lipid metabolism. We found that these lipids contributed to cachexia by influencing muscle and liver metabolism, and could be targeted using the ceramide synthesis inhibitor myriocin. Further connecting lipid and glucose metabolism, using glucose tracing into adipose tissue of cachectic and pre-cachectic mice, we identified substantial differences between cachectic and non-cachectic adipose tissue, particularly an altered flux of fatty acids and amino acids through the tricarboxylic acid cycle (TCA). Dysfunctional adipose tissue metabolism was partially linked to the TCA gatekeeper PDK4.
Both disturbed lipid and glucose metabolism are early events in cachexia development, and impaired glucose metabolism reportedly precedes cachexia in patients with cancer. We report here that patients with disturbed glucose metabolism showed a higher incidence of cachexia associated with pancreatic and colorectal cancers, and weight loss and inflammation were worse when diabetes and cachexia co-existed in these patients. Cachexia induced a strong infiltration of inflammatory cells, mainly macrophages, into islets and the exocrine pancreas of cachectic mice, inducing a phenotype resembling pancretitis, which may explain why the additional metabolic challenge of diabetes is detrimental in cachexia. Overall, STOPWASTE has so far identified novel biomarkers, disease heterogeneity, and tissue-intrinsic mechanisms contributing to the pathogenesis of cancer cachexia.
Using the Lipidyzer platform, we have created a lipidomic profile of plasma of C26 mice in pre-cachexia and cachexia. We have compared this lipidomic profile to that of additional cachexia mouse models, namely the SW480 model, the APCMin/+ and the LLC Lewis Lung Cancer model. As non-cachectic cancer model, we used the NC26 mice, as well as C26 tumor bearing pre-cachectic mice. We have also compared the lipidomic profile of the cachectic animals to that of patients with cachexia or non-cachectic cancer (collaboration Professor Marilia Seelaender, University of São Paolo). We have measured the expression of key enzymes of ceramide metabolism in adipose tissue, tumor, muscle, and liver of cachectic mice and patients, and identified the liver as likely source of the elevated circulating ceramides. Tissue lipidomics additionally identified alterations to liver lipids, specifically modified ceramides, in liver biopsies of cachectic mice and patients. We have measured the effect of ceramides or ceramide inhibition on adipocytes, muscle cells, and hepatocytes in the cell culture. Further, we have measured the effect of different ceramide synthesis inhibitors on cachexia development in vivo in the C26 mouse model of cachexia, and found myriocin to efficiently block ceramide synthesis and improve several cachexia readouts in these mice.
Overall, this set of experiments demonstrated that ceramides can serve as biomarkers for the early detection of cachexia, and stem from dysfunctional liver lipid metabolism. In cachexia, elevated ceramides cause muscle atrophy and alterations to liver mitochondrial metabolism, that can partially be reversed by the treatment with myriocin.
Using 13C glucose tracing and metabolomics, we have performed in vivo substrate tracing in the C26 mouse model of cachexia over the time course of disease development. We have further performed transcriptomics of adipose tissue, muscle, liver, and tumor, and proteomics of muscle and liver, and are currently integrating the data together with Dr. Dominik Lutter (Helmholtz Munich). We have produced preliminary experiments to validate adipocyte-intrinsic wasting cycles in the cell culture. This set of data is still under investigation, but preliminary data indicate that substrate flux in cachectic adipose tissue is disturbed and can partially be restored by targeting PDK4.
To better understand glucose homeostasis in cachexia, we have performed a range of glucose and insulin tolerance tests over various time points of cachexia development in C26 mice, and the control NC26 mice. We found no glucose or insulin intolerance in these mice, irrespective of their state of cachexia. We have further assessed islet hormone secretion and other indices of pancreatic dysfunction, and found that pancreatic inflammation was associated with cachexia, but not the presence of a tumor. Bulk sequencing of pancreatic islets has further confirmed the inflammatory state of the cachectic islets. First experiments to investigate the crosstalk between cancer cells and pancreatic beta-cells as well as macrophages have been performed in the cell culture and will be expanded. Lastly, collaborating with Dr. Olga Prokopchuk (Technical University Munich), we have analysed clinical data of patients with cachexia and found a close association between disturbed glucose homeostasis and cachexia in patients with pancreatic and colorectal cancer, highlighting that glucose metabolism is indeed important for the etiology of cachexia.
Overall, this set of experiments demonstrated that ceramides can serve as biomarkers for the early detection of cachexia, and stem from dysfunctional liver lipid metabolism. In cachexia, elevated ceramides cause muscle atrophy and alterations to liver mitochondrial metabolism, that can partially be reversed by the treatment with myriocin.
Using 13C glucose tracing and metabolomics, we have performed in vivo substrate tracing in the C26 mouse model of cachexia over the time course of disease development. We have further performed transcriptomics of adipose tissue, muscle, liver, and tumor, and proteomics of muscle and liver, and are currently integrating the data together with Dr. Dominik Lutter (Helmholtz Munich). We have produced preliminary experiments to validate adipocyte-intrinsic wasting cycles in the cell culture. This set of data is still under investigation, but preliminary data indicate that substrate flux in cachectic adipose tissue is disturbed and can partially be restored by targeting PDK4.
To better understand glucose homeostasis in cachexia, we have performed a range of glucose and insulin tolerance tests over various time points of cachexia development in C26 mice, and the control NC26 mice. We found no glucose or insulin intolerance in these mice, irrespective of their state of cachexia. We have further assessed islet hormone secretion and other indices of pancreatic dysfunction, and found that pancreatic inflammation was associated with cachexia, but not the presence of a tumor. Bulk sequencing of pancreatic islets has further confirmed the inflammatory state of the cachectic islets. First experiments to investigate the crosstalk between cancer cells and pancreatic beta-cells as well as macrophages have been performed in the cell culture and will be expanded. Lastly, collaborating with Dr. Olga Prokopchuk (Technical University Munich), we have analysed clinical data of patients with cachexia and found a close association between disturbed glucose homeostasis and cachexia in patients with pancreatic and colorectal cancer, highlighting that glucose metabolism is indeed important for the etiology of cachexia.
The connection between lipid and glucose metabolism is still understudied. Exemplary for this, there is no multi-omics metabolic model for cachexia available to date. STOPWASTE is aiming to change this, and the first results of this multi-scale inter-disciplinary project are expected to be published within the next year. To date, we have been the first to describe the connection between dysfunctional glucose homeostasis and cachexia progression in patients. Considering the increasing number of diabetic patients, this is of high relevance to a large percentage of patients, as they need to be monitored more closely for weight loss, appetite, and muscle performance. In other metabolic disease contexts, the recently established concept of disease subtypes has started to improve our understanding of disease mechanisms and treatment options, for instance in obesity or type 2 diabetes. Our work on cachexia and diabetes has paved the way towards the description of disease subtypes in cachexia, which will be important for the future design of clinical trials. Until the end of the project, we expect to produce a comprehensive multi-omics atlas of cachectic metabolism and identify targetable metabolic cycles to counteract cachexia.