Browsing by Subject "SUMO-1 Protein"

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    HB007 Administration Inhibits LN-229 and Patient-Derived Neurospheroid Glioblastoma Cell Growth With the Degradation of SUMO1 and Cell Cycle Regulator CDK4​
    (2023-07-27) Dougherty, Carson; Wohlford, Reagan; Jung, Sunghan; Hao, Chunhai
    Background and Hypothesis: Glioblastoma is the most common and malignant brain cancer and there is no effective therapy currently available to patients with this malignancy. Small ubiquitin-related modifier 1 (SUMO1) is a key regulator of cancer cell proliferation through its role in its modification of cellular proteins in various human cancers, especially glioblastoma. Degradation of SUMO1 through small molecule degrader, HB007, has been shown to inhibit growth in cancer cell lines and xenografts. Here, we hypothesize that HB007 can inhibit the glioblastoma cell growth through degradation of SUMO1 protein in glioblastoma cells and the cancer stem cell enriched neurospheres. Experimental Design: LN-229 glioblastoma cell viability was measured in response to increasing concentrations of HB007. LN-229 and patient-derived neurospheroid glioblastoma cells were cultured and seeded in 4 different plates at 1000 cells/ml concentrations before being treated with HB007 at increasing concentrations encircling the previously described IC50. Cells were then subjected to a SUMO lysis buffer and analyzed via western blot with antibodies specific to SUMO1, CDK4, and actin. Results: HB007 treated LN-229 cells exhibited an IC50 of 1.470µM. Western blot analysis confirmed the dose dependent reduction in SUMO-1-ylated proteins in HB007 treated cells. A reduction in CDK4 confirmed that cell progression is halted in a dose dependent manner in LN-229 and patient-derived neurospheroid glioblastoma cells when treated with HB007. Specificity of HB007 is towards SUMO1 with no nonspecific degradation of SUMO2/3. Conclusion: The cell growth of LN-229 and patient-derived neurospheroid glioblastoma cells was confirmed, through western blot, to be inhibited in a dose dependent manner by HB007. These results further establish the therapeutic potential of SUMO1 degraders as a novel anticancer drug for glioblastoma therapy. In the future, it is hoped that the bioavailability, potency, and blood brain barrier permeability can be improved to make this drug a potential treatment for patients. Presentation recording available online: https://purl.dlib.indiana.edu/iudl/media/k71n501c5g
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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.