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Spermine Synthase And Myc Cooperate To Maintain Colorectal Cancer Cell Survival By Repressing Bim Expression, Yubin Guo, Qing Ye, Pan Deng, Yanan Cao, Daheng He, Zhaohe Zhou, Chi Wang, Yekaterina Y. Zaytseva, Charles E. Schwartz, Eun Young Lee, B. Mark Evers, Andrew J. Morris, Side Liu, Qing-Bai She

Markey Cancer Center Faculty Publications

Dysregulation of polyamine metabolism has been linked to the development of colorectal cancer (CRC), but the underlying mechanism is incompletely characterized. Here, we report that spermine synthase (SMS), a polyamine biosynthetic enzyme, is overexpressed in CRC. Targeted disruption of SMS in CRC cells results in spermidine accumulation, which inhibits FOXO3a acetylation and allows subsequent translocation to the nucleus to transcriptionally induce expression of the proapoptotic protein Bim. However, this induction is blunted by MYC-driven expression of miR-19a and miR-19b that repress Bim production. Pharmacological or genetic inhibition of MYC activity in SMS-depleted CRC cells dramatically induces Bim expression and apoptosis …