Browsing by Author "Drapkin, Ronny"

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    Deubiquitinase UCHL1 Maintains Protein Homeostasis through the PSMA7–APEH–Proteasome Axis in High-grade Serous Ovarian Carcinoma
    (AACR, 2021-07) Tangri, Apoorva; Lighty, Kinzie; Loganathan, Jagadish; Mesmar, Fahmi; Podicheti, Ram; Zhang, Chi; Iwanicki, Marcin; Drapkin, Ronny; Nakshatri, Harikrishna; Mitra, Sumegha; Obstetrics and Gynecology, School of Medicine
    High-grade serous ovarian cancer (HGSOC) is characterized by chromosomal instability, DNA damage, oxidative stress, and high metabolic demand that exacerbate misfolded, unfolded, and damaged protein burden resulting in increased proteotoxicity. However, the underlying mechanisms that maintain protein homeostasis to promote HGSOC growth remain poorly understood. This study reports that the neuronal deubiquitinating enzyme, ubiquitin carboxyl-terminal hydrolase L1 (UCHL1), is overexpressed in HGSOC and maintains protein homeostasis. UCHL1 expression was markedly increased in HGSOC patient tumors and serous tubal intraepithelial carcinoma (HGSOC precursor lesions). High UCHL1 levels correlated with higher tumor grade and poor patient survival. UCHL1 inhibition reduced HGSOC cell proliferation and invasion, as well as significantly decreased the in vivo metastatic growth of ovarian cancer xenografts. Transcriptional profiling of UCHL1-silenced HGSOC cells revealed downregulation of genes implicated with proteasome activity along with upregulation of endoplasmic reticulum stress–induced genes. Reduced expression of proteasome subunit alpha 7 (PSMA7) and acylaminoacyl peptide hydrolase (APEH), upon silencing of UCHL1, resulted in a significant decrease in proteasome activity, impaired protein degradation, and abrogated HGSOC growth. Furthermore, the accumulation of polyubiquitinated proteins in the UCHL1-silenced cells led to attenuation of mTORC1 activity and protein synthesis, and induction of terminal unfolded protein response. Collectively, these results indicate that UCHL1 promotes HGSOC growth by mediating protein homeostasis through the PSMA7–APEH–proteasome axis.This study identifies the novel links in the proteostasis network to target protein homeostasis in HGSOC and recognizes the potential of inhibiting UCHL1 and APEH to sensitize cancer cells to proteotoxic stress in solid tumors.
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    In vivo modeling of metastatic human high-grade serous ovarian cancer in mice
    (PLOS, 2020-06-04) Kim, Olga; Park, Eun Young; Klinkebiel, David L.; Pack, Svetlana D.; Shin, Yong-Hyun; Abdullaev, Zied; Emerson, Robert E.; Coffey, Donna M.; Kwon, Sun Young; Creighton, Chad J.; Kwon, Sanghoon; Chang, Edmund C.; Chiang, Theodore; Yatsenko, Alexander N.; Chien, Jeremy; Cheon, Dong-Joo; Yang-Hartwich, Yang; Nakshatri, Harikrishna; Nephew, Kenneth P.; Behringer, Richard R.; Fernández, Facundo M.; Cho, Chi-Heum; Vanderhyden, Barbara; Drapkin, Ronny; Bast, Robert C., Jr.; Miller, Kathy D.; Karpf, Adam R.; Kim, Jaeyeon; Biochemistry and Molecular Biology, School of Medicine
    Metastasis is responsible for 90% of human cancer mortality, yet it remains a challenge to model human cancer metastasis in vivo. Here we describe mouse models of high-grade serous ovarian cancer, also known as high-grade serous carcinoma (HGSC), the most common and deadliest human ovarian cancer type. Mice genetically engineered to harbor Dicer1 and Pten inactivation and mutant p53 robustly replicate the peritoneal metastases of human HGSC with complete penetrance. Arising from the fallopian tube, tumors spread to the ovary and metastasize throughout the pelvic and peritoneal cavities, invariably inducing hemorrhagic ascites. Widespread and abundant peritoneal metastases ultimately cause mouse deaths (100%). Besides the phenotypic and histopathological similarities, mouse HGSCs also display marked chromosomal instability, impaired DNA repair, and chemosensitivity. Faithfully recapitulating the clinical metastases as well as molecular and genomic features of human HGSC, this murine model will be valuable for elucidating the mechanisms underlying the development and progression of metastatic ovarian cancer and also for evaluating potential therapies.
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    ZNFX1 is a Novel Master Regulator in Epigenetically-induced Pathogen Mimicry and Inflammasome Signaling in Cancer
    (bioRxiv, 2024-10-21) Stojanovic, Lora; Abbotts, Rachel; Tripathi, Kaushlendra; Coon, Collin M.; Rajendran, Saranya; Farid, Elnaz Abbasi; Hostetter, Galen; Guarnieri, Joseph W.; Wallace, Douglas C.; Liu, Sheng; Wan, Jun; Calendo, Gennaro; Marker, Rebecca; Gohari, Zahra; Inayatullah, Mohammed M. A.; Tiwari, Vijay K.; Kader, Tanjina; Santagata, Sandro; Drapkin, Ronny; Kommoss, Stefan; Pfisterer, Jacobus; Konecny, Gottfried E.; Coopergard, Ryan; Issa, Jean-Pierre; Winterhoff, Boris J. N.; Topper, Michael J.; Sandusky, George E.; Miller, Kathy D.; Baylin, Stephen B.; Nephew, Kenneth P.; Rassool, Feyruz V.; Medical and Molecular Genetics, School of Medicine
    DNA methyltransferase and poly(ADP-ribose) polymerase inhibitors (DNMTis, PARPis) induce a stimulator of interferon (IFN) genes (STING)-dependent pathogen mimicry response (PMR) in ovarian (OC) and other cancers. We now show that combining DNMTis and PARPis upregulates expression of a little-studied nucleic-acid sensor, NFX1-type zinc finger-containing 1 protein (ZNFX1). We demonstrate that ZNFX1 is a novel master regulator for PMR induction in mitochondria, serving as a gateway for STING-dependent PMR. In patient OC databases, high ZNFX1 expression levels correlate with advanced stage disease. ZNFX1 expression alone significantly correlates with an increase in overall survival in a phase 3 trial for therapy-resistant OC patients receiving bevacizumab in combination with chemotherapy. In correlative RNA-seq data, inflammasome signaling through ZNFX1 correlates with abnormal vasculogenesis. ZNFX1 controls PMR signaling through the mitochondria and may serve as a biomarker to facilitate offering personalized therapy in OC patients, highlighting the strong translational significance of our findings.