| First Author | Zhang G | Year | 2011 |
| Journal | EMBO J | Volume | 30 |
| Issue | 20 | Pages | 4323-35 |
| PubMed ID | 21847090 | Mgi Jnum | J:177199 |
| Mgi Id | MGI:5294486 | Doi | 10.1038/emboj.2011.292 |
| Citation | Zhang G, et al. (2011) C/EBPbeta mediates tumour-induced ubiquitin ligase atrogin1/MAFbx upregulation and muscle wasting. EMBO J 30(20):4323-35 |
| abstractText | Upregulation of ubiquitin ligase atrogin1/MAFbx and muscle wasting are hallmarks of cancer cachexia; however, the underlying mechanism is undefined. Here, we describe a novel signalling pathway through which Lewis lung carcinoma (LLC) induces atrogin1/MAFbx upregulation and muscle wasting. C2C12 myotubes treated with LLC-conditioned medium (LCM) rapidly activates p38 MAPK and AKT while inactivating FoxO1/3, resulting in atrogin1/MAFbx upregulation, myosin heavy chain loss, and myotube atrophy. The p38alpha/beta MAPK inhibitor SB202190 blocks the catabolic effects. Upon activation, p38 associates with C/EBPbeta resulting in its phosphorylation and binding to a C/EBPbeta-responsive cis-element in the atrogin1/MAFbx gene promoter. The promoter activity is stimulated by LCM via p38beta-mediated activation of the C/EBPbeta-responsive cis-element, independent of the adjacent FoxO1/3-responsive cis-elements in the promoter. In addition, p38 activation is observed in the muscle of LLC tumour-bearing mice, and SB202190 administration blocks atrogin1/MAFbx upregulation and muscle protein loss. Furthermore, C/EBPbeta(-/-) mice are resistant to LLC tumour-induced atrogin1/MAFbx upregulation and muscle wasting. Therefore, activation of the p38beta MAPK-C/EBPbeta signalling pathway appears a key component of the pathogenesis of LLC tumour-induced cachexia. |
