p97 has recently emerged as a therapeutic target for cancer due to its essential functions in protein homeostasis. CB-5083 is a first-in-class, potent and selective ATP-competitive p97 inhibitor that induces proteotoxic stress in cancer cells. Potential mechanisms regulating the sensitivity of cells to p97 inhibition remain poorly studied. Here, we demonstrate that Thrombospondin-1 (THBS1) is a CB-5083-upregulated gene that helps confer resistance of HCT116 cells to CB-5083. Our immunoblotting and immunofluorescence data showed that CB-5083 significantly increases the steady-state abundance of THBS1. Blockade of THBS1 induction sensitized cells to CB-5083-mediated growth inhibition. Suppression of THBS1 caused an increase of CB-5083-induced sub-G1 population and caspase 3/7 activity suggesting that its function is linked to the survival of cancer cells in response to p97 inhibition. Altogether our data provide new evidence that THBS1 is important for the susceptibility of cells to p97 inhibition.
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http://dx.doi.org/10.1080/15384101.2020.1754584 | DOI Listing |
Int J Mol Sci
December 2024
Department of Biology, Texas Southern University, Houston, TX 77004, USA.
Previous data show that the knockdown of the gene in the MDA-MB-231 cell line leads to the downregulation of gene expression. In addition, and genes are co-expressed and dysregulated in some of the same triple negative breast cancer patient samples. We propose that the co-expression of the two genes is attributed to the MYBL1 transcription factor regulation of the gene.
View Article and Find Full Text PDFMol Biol Cell
January 2025
Dept. of Biochemistry & Molecular Biology, University of Nebraska Medical Center, Omaha, NE, 68198.
The primary cilium is a crucial signaling organelle that can be generated by most human cells, and impediments to primary ciliogenesis lead to a variety of developmental disorders known as ciliopathies. The removal of the capping protein, CP110, from the mother centriole is a crucial early step that promotes generation of the ciliary vesicle and ciliogenesis. Recent studies have demonstrated that CP110 undergoes polyubiquitination and degradation in the proteosome, but the mechanisms of unfolding and removal from the mother centriole remain unknown.
View Article and Find Full Text PDFExp Mol Med
January 2025
Department of Cell Biology, Harvard Medical School, 240 Longwood Avenue, Boston, MA, 02115, USA.
In response to extra- and intracellular stimuli that constantly challenge and disturb the proteome, cells rapidly change their proteolytic capacity to maintain proteostasis. Failure of such efforts often becomes a major cause of diseases or is associated with exacerbation. Increase in protein breakdown occurs at multiple steps in the ubiquitin-proteasome system, and the regulation of ubiquitination has been extensively studied.
View Article and Find Full Text PDFDNA Cell Biol
January 2025
Research Center of Integrated Traditional Chinese and Western Medicine, The Affiliated Traditional Chinese Medicine Hospital, Southwest Medical University, Luzhou 646000, China.
Liver fibrosis, one of the main histological determinants of various chronic liver diseases, currently lacks effective treatment. Hepatic stellate cells (HSCs) are pivotal in the production of extracellular matrix and amplify the fibrogenic response. Inhibiting the activation of HSCs or promoting the senescence of activated HSCs is crucial for the regression of liver fibrosis.
View Article and Find Full Text PDFNat Cell Biol
January 2025
Biochemistry Section, Surgical Neurology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA.
Mitochondrial protein import through the outer and inner membranes is key to mitochondrial biogenesis. Recent studies have explored how cells respond when import is impaired by a variety of different insults. Here, we developed a mammalian import blocking system using dihydrofolate reductase fused to the N terminus of the inner membrane protein MIC60.
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