IGFBP-3 promotes cachexia-associated lipid loss by suppressing insulin-like growth factor/insulin signaling / 中华医学杂志(英文版)

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.

The role of insulin like growth factor (IGF)–1 and IGF-binding protein-3 in diagnosis of growth hormone deficiency in short stature children.

Objective. To evaluate the role of IGF-1 and IGFBP-3 in diagnosis of short stature children and adolescents in whom Growth Hormone Deficiency (GHD) was found. Methods. In this cross sectional study the referred short stature children and adolescents to Namazi Hospital in Shiraz- Iran, in 2003-2005 were studied. The inclusion criteria were proved short stature based on the physical examination, weight, height, standard deviation score (SDS) of height < -2 , with considering stage of puberty and predicted height in children without any genetic or chronic disorders. The exclusion criteria were any positive physical or laboratory data suggesting hypothyroidism, rickets or liver disorders. For all patients a provocative growth hormone test was performed with propranolol and L-dopa and serum IGF-1 and IGFBP-3 were measured. GHD defined as peak(cutoff ) serum GH level under 10 ìg/L and low IGF-1 and IGFBP-3 considered as cutoff serum level under -2 standard deviation. Results. Eighty one short stature patients (39 boys and 42 girls) with mean age of 10.6 ± 3.5 years completed the study. Seventeen patients with GHD were found and in 18 patients IGF-1 level were low. Only in 6 patients both GH and IGF-1 were low and 2 of them had low IGFBP-3. There were no correlations between the levels of GH,IGF-1 and IGFBP-3 in children with short stature due to GHD. The sensitivity and specifity of IGF-1 and IGFBP-3 in assessment of GHD were 35% and 81% for IGF-1 and 12% and 94% for IGFBP-3, respectively. Conclusion. No correlations were found between GH level and serum levels of IGF-1 and IGFBP-3 in short patients and the sensitivity of these tests in assessment of GHD was poor.