151. TRB3 links insulin/IGF to tumour promotion by interacting with p62 and impeding autophagic/proteasomal degradations.
- Author
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Hua F, Li K, Yu JJ, Lv XX, Yan J, Zhang XW, Sun W, Lin H, Shang S, Wang F, Cui B, Mu R, Huang B, Jiang JD, and Hu ZW
- Subjects
- Adaptor Proteins, Signal Transducing genetics, Adenine analogs & derivatives, Adenine pharmacology, Animals, Autophagy physiology, Cell Cycle Proteins genetics, Cell Movement, Humans, Insulin Receptor Substrate Proteins genetics, Insulin Receptor Substrate Proteins metabolism, Insulin-Like Growth Factor I genetics, Leupeptins pharmacology, Male, Mice, Mice, Inbred C57BL, Mice, Nude, Neoplasm Metastasis, Neoplasms, Experimental, Protein Serine-Threonine Kinases genetics, Protein Serine-Threonine Kinases metabolism, Repressor Proteins genetics, Sequestosome-1 Protein, Tissue Array Analysis, Ubiquitin physiology, Adaptor Proteins, Signal Transducing metabolism, Cell Cycle Proteins metabolism, Gene Expression Regulation, Neoplastic physiology, Insulin metabolism, Insulin-Like Growth Factor I metabolism, Proteasome Endopeptidase Complex physiology, Protein Serine-Threonine Kinases antagonists & inhibitors, Repressor Proteins metabolism
- Abstract
High insulin/IGF is a biologic link between diabetes and cancers, but the underlying molecular mechanism remains unclear. Here we report a previously unrecognized tumour-promoting mechanism for stress protein TRB3, which mediates a reciprocal antagonism between autophagic and proteasomal degradation systems and connects insulin/IGF to malignant promotion. We find that several human cancers express higher TRB3 and phosphorylated insulin receptor substrate 1, which correlates negatively with patient's prognosis. TRB3 depletion protects against tumour-promoting actions of insulin/IGF and attenuates tumour initiation, growth and metastasis in mice. TRB3 interacts with autophagic receptor p62 and hinders p62 binding to LC3 and ubiquitinated substrates, which causes p62 deposition and suppresses autophagic/proteasomal degradation. Several tumour-promoting factors accumulate in cancer cells to support tumour metabolism, proliferation, invasion and metastasis. Interrupting TRB3/p62 interaction produces potent antitumour efficacies against tumour growth and metastasis. Our study opens possibility of targeting this interaction as a potential novel strategy against cancers with diabetes.
- Published
- 2015
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