Abstract
BackgroundCancer cachexia (CAC) reduces patient survival and quality of life. Developments of efficient therapeutic strategies are required for the CAC treatments. This long-term process could be shortened by the drug-repositioning approach which exploits old drugs approved for non-cachexia disease. Amiloride, a diuretic drug, is clinically used for treatments of hypertension and edema due to heart failure. Here, we explored the effects of the amiloride treatment for ameliorating muscle wasting in murine models of cancer cachexia.MethodsThe CT26 and LLC tumor cells were subcutaneously injected into mice to induce colon cancer cachexia and lung cancer cachexia, respectively. Amiloride was intraperitoneally injected daily once tumors were formed. Cachexia features of the CT26 model and the LLC model were separately characterized by phenotypic, histopathologic and biochemical analyses. Plasma exosomes and muscle atrophy-related proteins were quantitatively analyzed. Integrative NMR-based metabolomic and transcriptomic analyses were conducted to identify significantly altered metabolic pathways and distinctly changed metabolism-related biological processes in gastrocnemius.ResultsThe CT26 and LLC cachexia models displayed prominent cachexia features including decreases in body weight, skeletal muscle, adipose tissue, and muscle strength. The amiloride treatment in tumor-bearing mice distinctly alleviated muscle atrophy and relieved cachexia-related features without affecting tumor growth. Both the CT26 and LLC cachexia mice showed increased plasma exosome densities which were largely derived from tumors. Significantly, the amiloride treatment inhibited tumor-derived exosome release, which did not obviously affect exosome secretion from non-neoplastic tissues or induce observable systemic toxicities in normal healthy mice. Integrative-omics revealed significant metabolic impairments in cachectic gastrocnemius, including promoted muscular catabolism, inhibited muscular protein synthesis, blocked glycolysis, and impeded ketone body oxidation. The amiloride treatment evidently improved the metabolic impairments in cachectic gastrocnemius.ConclusionsAmiloride ameliorates cachectic muscle wasting and alleviates cancer cachexia progression through inhibiting tumor-derived exosome release. Our results are beneficial to understanding the underlying molecular mechanisms, shedding light on the potentials of amiloride in cachexia therapy.
Highlights
Cachexia is a systemic metabolic syndrome defined by involuntary body weight and skeletal muscle loss and cannot be fully reversed by conventional nutritional supplementations [1]
Given that tumor-derived exosomes are implicated in mediating cachectic muscle wasting, we speculated that amiloride might have some effects for ameliorating muscle wasting in cancer cachexia
Our results reveal that amiloride is a potential therapeutic drug capable of ameliorating muscle wasting in cancer cachexia through inhibiting tumor-derived exosome release (Fig. 8)
Summary
Cachexia is a systemic metabolic syndrome defined by involuntary body weight and skeletal muscle loss (with or without fat loss) and cannot be fully reversed by conventional nutritional supplementations [1]. Mounting researches indicated that tumorderived exosomes contribute to cancer cachexia through mediating the cross-talk between tumors and distally located skeletal muscles, resulting in decreased muscle weight, impaired organismal function, suppressed therapeutical response, and reduced quality of life, as well as remarkably enhanced cancer-related mortality [7,8,9,10]. These works might provide a new strategy for the CAC treatments based on inhibition of tumor-derived exosomes release. We explored the effects of the amiloride treatment for ameliorating muscle wasting in murine models of cancer cachexia
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