UFD1 contributes to MYC-mediated leukemia aggressiveness through suppression of the proapoptotic unfolded protein response

作者:Huiting, L. N.; Samaha, Y.; Zhang, G. L.; Roderick, J. E.; Li, B.; Anderson, N. M.; Wang, Y. W.; Wang, L.; Laroche, F. J. F.; Choi, J. W.; Liu, C. T.; Kelliher, M. A.; Feng, H.*
来源:Leukemia, 2018, 32(11): 2339-2351.
DOI:10.1038/s41375-018-0141-x

摘要

Despite the pivotal role of MYC in tumorigenesis, the mechanisms by which it promotes cancer aggressiveness remain incompletely understood. Here, we show that MYC transcriptionally upregulates the ubiquitin fusion degradation 1 (UFD1) gene in T-cell acute lymphoblastic leukemia (T-ALL). Allelic loss of ufd1 in zebrafish induces tumor cell apoptosis and impairs MYC-driven T-ALL progression but does not affect general health. As the E2 component of an endoplasmic reticulum (ER)-associated degradation (ERAD) complex, UFD1 facilitates the elimination of misfolded/unfolded proteins from the ER. We found that UFD1 inactivation in human T-ALL cells impairs ERAD, exacerbates ER stress, and induces apoptosis. Moreover, we show that UFD1 inactivation promotes the proapoptotic unfolded protein response (UPR) mediated by protein kinase RNA-like ER kinase (PERK). This effect is demonstrated by an upregulation of PERK and its downstream effector C/EBP homologous protein (CHOP), as well as a downregulation of BCL2 and BCLxL. Indeed, CHOP inactivation or BCL2 overexpression is sufficient to rescue tumor cell apoptosis induced by UFD1 knockdown. Together, our studies identify UFD1 as a critical regulator of the ER stress response and a novel contributor to MYC-mediated leukemia aggressiveness, with implications for targeted therapy in T-ALL and likely other MYC-driven cancers.