Browsing by Author "Zhao, Yin Quan"

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    SUMO1 degrader induces ER stress and ROS accumulation through deSUMOylation of TCF4 and inhibition of its transcription of StarD7 in colon cancer
    (Wiley, 2023) Zhao, Yin Quan; Jin, Hong Ri; Kim, Daeho; Jung, Sung Han; Liu, Sheng; Wan, Jun; Lo, Ho-Yin; Fu, Xue Qi; Wang, Quan; Hao, Chunhai; Bellail, Anita C.; Pathology and Laboratory Medicine, School of Medicine
    Small molecule degraders of small ubiquitin-related modifier 1 (SUMO1) induce SUMO1 degradation in colon cancer cells and inhibits the cancer cell growth; however, it is unclear how SUMO1 degradation leads to the anticancer activity of the degraders. Genome-wide CRISPR-Cas9 knockout screens has identified StAR-related lipid transfer domain containing 7 (StarD7) as a critical gene for the degrader’s anticancer activity. Here, we show that both StarD7 mRNA and protein are overexpressed in human colon cancer and its knockout significantly reduces colon cancer cell growth and xenograft progression. The treatment with the SUMO1 degrader lead compound HB007 reduces StarD7 mRNA and protein levels and increases endoplasmic reticulum (ER) stress and reactive oxygen species (ROS) production in colon cancer cells and three-dimensional (3D) organoids. The study further provides a novel mechanism of the compound anticancer activity that SUMO1 degrader-induced decrease of StarD7 occur through degradation of SUMO1, deSUMOylation and degradation of T cell-specific transcription 4 (TCF4) and thereby inhibition of its transcription of StarD7 in colon cancer cells, 3D organoids and patient-derived xenografts (PDX).
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    Ubiquitination and degradation of SUMO1 by small-molecule degraders extends survival of mice with patient-derived tumors
    (AAAS, 2021) Bellail, Anita C.; Jin, Hong Ri; Lo, Ho-Yin; Jung, Sung Han; Hamdouchi, Chafiq; Kim, Daeho; Higgins, Ryan K.; Blanck, Maximilian; le Sage, Carlos; Cross, Benedict C. S.; Li, Jing; Mosley, Amber L.; Wijeratne, Aruna B.; Jiang, Wen; Ghosh, Manali; Zhao, Yin Quan; Hauck, Paula M.; Shekhar, Anantha; Hao, Chunhai; Pathology and Laboratory Medicine, School of Medicine
    Discovery of small-molecule degraders that activate ubiquitin ligase–mediated ubiquitination and degradation of targeted oncoproteins in cancer cells has been an elusive therapeutic strategy. Here, we report a cancer cell–based drug screen of the NCI drug-like compounds library that enabled identification of small-molecule degraders of the small ubiquitin-related modifier 1 (SUMO1). Structure-activity relationship studies of analogs of the hit compound CPD1 led to identification of a lead compound HB007 with improved properties and anticancer potency in vitro and in vivo. A genome-scale CRISPR-Cas9 knockout screen identified the substrate receptor F-box protein 42 (FBXO42) of cullin 1 (CUL1) E3 ubiquitin ligase as required for HB007 activity. Using HB007 pull-down proteomics assays, we pinpointed HB007’s binding protein as the cytoplasmic activation/proliferation-associated protein 1 (CAPRIN1). Biolayer interferometry and compound competitive immunoblot assays confirmed the selectivity of HB007’s binding to CAPRIN1. When bound to CAPRIN1, HB007 induced the interaction of CAPRIN1 with FBXO42. FBXO42 then recruited SUMO1 to the CAPRIN1-CUL1-FBXO42 ubiquitin ligase complex, where SUMO1 was ubiquitinated in several of human cancer cells. HB007 selectively degraded SUMO1 in patient tumor–derived xenografts implanted into mice. Systemic administration of HB007 inhibited the progression of patient-derived brain, breast, colon, and lung cancers in mice and increased survival of the animals. This cancer cell–based screening approach enabled discovery of a small-molecule degrader of SUMO1 and may be useful for identifying other small-molecule degraders of oncoproteins.