Background:Progressive lipid loss of adipose tissue is a major feature of cancer-associated cachexia.In addition to systemic immune/inflammatory effects in response to tumor progression,tumor-secreted cachectic ligand...Background:Progressive lipid loss of adipose tissue is a major feature of cancer-associated cachexia.In addition to systemic immune/inflammatory effects in response to tumor progression,tumor-secreted cachectic ligands also play essential roles in tumor-induced lipid loss.However,the mechanisms of tumor-adipose tissue interaction in lipid homeostasis are not fully understood.Methods:The yki-gut tumors were induced in fruit flies.Lipid metabolic assays were performed to investigate the lipolysis level of different types of insulin-like growth factor binding protein-3(IGFBP-3)treated cells.Immunoblotting was used to display phenotypes of tumor cells and adipocytes.Quantitative polymerase chain reaction(qPCR)analysis was carried out to examine the gene expression levels such as Acc1,Acly,and Fasn et al.Results:In this study,it was revealed that tumor-derived IGFBP-3 was an important ligand directly causing lipid loss in matured adipocytes.IGFBP-3,which is highly expressed in cachectic tumor cells,antagonized insulin/IGF-like signaling(IIS)and impaired the balance between lipolysis and lipogenesis in 3T3-L1 adipocytes.Conditioned medium from cachectic tumor cells,such as Capan-1 and C26 cells,contained excessive IGFBP-3 that potently induced lipolysis in adipocytes.Notably,neutralization of IGFBP-3 by neutralizing antibody in the conditioned medium of cachectic tumor cells significantly alleviated the lipolytic effect and restored lipid storage in adipocytes.Furthermore,cachectic tumor cells were resistant to IGFBP-3 inhibition of IIS,ensuring their escape from IGFBP-3-associated growth suppression.Finally,cachectic tumor-derived ImpL2,the IGFBP-3 homolog,also impaired lipid homeostasis of host cells in an established cancer-cachexia model in Drosophila.Most importantly,IGFBP-3 was highly expressed in cancer tissues in pancreatic and colorectal cancer patients,especially higher in the sera of cachectic cancer patients than non-cachexia cancer patients.Conclusion:Our study demonstrates that tumor-derived IGFBP-3 plays a critical role in cachexia-associated lipid loss and could be a biomarker for diagnosis of cachexia in cancer patients.展开更多
基金National Natural Science Foundation of China(No.82073876)Beijing Natural Science Foundation(No.7202012)
文摘Background:Progressive lipid loss of adipose tissue is a major feature of cancer-associated cachexia.In addition to systemic immune/inflammatory effects in response to tumor progression,tumor-secreted cachectic ligands also play essential roles in tumor-induced lipid loss.However,the mechanisms of tumor-adipose tissue interaction in lipid homeostasis are not fully understood.Methods:The yki-gut tumors were induced in fruit flies.Lipid metabolic assays were performed to investigate the lipolysis level of different types of insulin-like growth factor binding protein-3(IGFBP-3)treated cells.Immunoblotting was used to display phenotypes of tumor cells and adipocytes.Quantitative polymerase chain reaction(qPCR)analysis was carried out to examine the gene expression levels such as Acc1,Acly,and Fasn et al.Results:In this study,it was revealed that tumor-derived IGFBP-3 was an important ligand directly causing lipid loss in matured adipocytes.IGFBP-3,which is highly expressed in cachectic tumor cells,antagonized insulin/IGF-like signaling(IIS)and impaired the balance between lipolysis and lipogenesis in 3T3-L1 adipocytes.Conditioned medium from cachectic tumor cells,such as Capan-1 and C26 cells,contained excessive IGFBP-3 that potently induced lipolysis in adipocytes.Notably,neutralization of IGFBP-3 by neutralizing antibody in the conditioned medium of cachectic tumor cells significantly alleviated the lipolytic effect and restored lipid storage in adipocytes.Furthermore,cachectic tumor cells were resistant to IGFBP-3 inhibition of IIS,ensuring their escape from IGFBP-3-associated growth suppression.Finally,cachectic tumor-derived ImpL2,the IGFBP-3 homolog,also impaired lipid homeostasis of host cells in an established cancer-cachexia model in Drosophila.Most importantly,IGFBP-3 was highly expressed in cancer tissues in pancreatic and colorectal cancer patients,especially higher in the sera of cachectic cancer patients than non-cachexia cancer patients.Conclusion:Our study demonstrates that tumor-derived IGFBP-3 plays a critical role in cachexia-associated lipid loss and could be a biomarker for diagnosis of cachexia in cancer patients.
