scholarly journals SerpinB3 drives cancer stem cell survival in glioblastoma

2021 ◽  
Author(s):  
Adam Lauko ◽  
Josephine Volovetz ◽  
Soumya M Turaga ◽  
Defne Bayik ◽  
Dennis C Watson ◽  
...  
Keyword(s):  
Cell Death ◽  
Protease Inhibitor ◽  
Cysteine Protease ◽  
Cathepsin L ◽  
Standard Of Care ◽  
Surface Expression ◽  
Therapeutic Interventions ◽  
Cysteine Protease Inhibitor ◽  
Cell Surface Expression ◽  
Downstream Signaling

Despite therapeutic interventions for glioblastoma (GBM), cancer stem cells (CSCs) drive recurrence. The precise mechanisms underlying CSC therapeutic resistance, namely inhibition of cell death, are unclear. We built on previous observations that the high cell surface expression of junctional adhesion molecule-A drives CSC maintenance and identified downstream signaling networks, including the cysteine protease inhibitor SerpinB3. Using genetic depletion approaches, we found that SerpinB3 is necessary for CSC maintenance, survival, and tumor growth, as well as CSC pathway activation. The knockdown of SerpinB3 also increased apoptosis and susceptibility to radiation therapy. Mechanistically, SerpinB3 was essential to buffer cathepsin L-mediated cell death, which was enhanced with radiation. Finally, we found that SerpinB3 knockdown dramatically increased the efficacy of radiation in pre-clinical models. Taken together, our findings identify a novel GBM CSC-specific survival mechanism involving a previously uninvestigated cysteine protease inhibitor, SerpinB3, and provide a potential target to improve the efficacy of standard-of-care GBM therapies against therapeutically resistant CSCs.

STEM-15. SerpinB3 DRIVES CANCER STEM CELL SURVIVAL IN GLIOBLASTOMA

2021 ◽  
Vol 23 (Supplement_6) ◽  
pp. vi24-vi24
Author(s):  
Adam Lauko ◽  
Soumya M Turaga ◽  
Josephine Volovetz ◽  
Defne Bayik ◽  
Shideng Bao ◽  
...  
Keyword(s):  
Cell Death ◽  
Protease Inhibitor ◽  
Cysteine Protease ◽  
Xenograft Model ◽  
Standard Of Care ◽  
Therapeutic Interventions ◽  
Cysteine Protease Inhibitor ◽  
Orthotopic Xenograft Model

Abstract Despite therapeutic interventions for glioblastoma (GBM), self-renewing, therapy-resistant populations of cells referred to as cancer stem cells (CSCs) drive recurrence. Previously, we identified the unique expression of junctional adhesion molecule-A (JAM-A) on CSCs and demonstrated that JAM-A is both necessary and sufficient for self-renewal and tumor growth. Moreover, we determined that JAM-A signals via Akt in GBM CSCs to sustain pluripotency transcription factor activity; however, the entire signaling network has yet to be fully elucidated. To further delineate this pathway, we immunoprecipitated JAM-A from patient-derived GBM CSCs and performed mass spectrometry to determine JAM-A binding proteins. This led to the identification of the cysteine protease inhibitor SerpinB3 as a putative JAM-A binding partner. Using in vitro CSC functional assays, we show that SerpinB3 is necessary for CSC maintenance and survival. In an in vivo orthotopic xenograft model, knockdown of SerpinB3 extended survival. Mechanistically, knockdown of SerpinB3 led to decreased expression of TGF-β, Myc, WNT, and Notch signaling, known regulators of the CSC state. Additionally, knockdown of SerpinB3 increases susceptibility to radiation therapy. SerpinB3 is essential for buffering cells against cathepsin-mediated cell death, and we found that elevated lysosomal membrane permeability after radiation leads to cathepsin release into the cytoplasm. As a result, SerpinB3 knockdown cells have a diminished capacity to inhibit cathepsin-driven cell death after radiation. The addition of the cathepsin inhibitor E64D partially rescues the SerpinB3 knockdown, however, SerpinB3 mutants that are unable to inhibit cathepsins fail to do the same. Taken together, our findings, identify a novel GBM CSC-specific survival mechanism involving a previously uninvestigated cysteine protease inhibitor, SerpinB3, and provide a potential target to increase the efficacy of standard of care GBM therapies against therapy-resistant CSCs.

A cysteine protease inhibitor blocks SARS-CoV-2 infection of human and monkey cells

2020 ◽  
Author(s):  
Drake M. Mellott ◽  
Chien-Te Tseng ◽  
Aleksandra Drelich ◽  
Pavla Fajtová ◽  
Bala C. Chenna ◽  
...  
Keyword(s):  
Protease Inhibitor ◽  
Host Cell ◽  
Cysteine Protease ◽  
Cleavage Site ◽  
Cathepsin L ◽  
Cysteine Proteases ◽  
Protein Processing ◽  
Spike Protein ◽  
Cysteine Protease Inhibitor ◽  
Viral Infectivity

ABSTRACTK777 is a di-peptide analog that contains an electrophilic vinyl-sulfone moiety and is a potent, covalent inactivator of cathepsins. Vero E6, HeLa/ACE2, Caco-2, A549/ACE2, and Calu-3, cells were exposed to SARS-CoV-2, and then treated with K777. K777 reduced viral infectivity with EC50 values of inhibition of viral infection of: 74 nM for Vero E6, <80 nM for A549/ACE2, and 4 nM for HeLa/ACE2 cells. In contrast, Calu-3 and Caco-2 cells had EC50 values in the low micromolar range. No toxicity of K777 was observed for any of the host cells at 10-100 μM inhibitor. K777 did not inhibit activity of the papain-like cysteine protease and 3CL cysteine protease, encoded by SARS-CoV-2 at concentrations of ≤ 100 μM. These results suggested that K777 exerts its potent anti-viral activity by inactivation of mammalian cysteine proteases which are essential to viral infectivity. Using a propargyl derivative of K777 as an activity-based probe, K777 selectively targeted cathepsin B and cathepsin L in Vero E6 cells. However only cathepsin L cleaved the SARS-CoV-2 spike protein and K777 blocked this proteolysis. The site of spike protein cleavage by cathepsin L was in the S1 domain of SARS-CoV-2, differing from the cleavage site observed in the SARS CoV-1 spike protein. These data support the hypothesis that the antiviral activity of K777 is mediated through inhibition of the activity of host cathepsin L and subsequent loss of viral spike protein processing.SIGNIFICANCEThe virus causing COVID-19 is highly infectious and has resulted in a global pandemic. We confirm that a cysteine protease inhibitor, approved by the FDA as a clinical-stage compound, inhibits SARS-CoV-2 infection of several human and monkey cell lines with notable(nanomolar) efficacy. The mechanism of action of this inhibitor is identified as a specific inhibition of host cell cathepsin L. This in turn inhibits host cell processing of the coronaviral spike protein, a step required for cell entry. Neither of the coronaviral proteases are inhibited, and the cleavage site of spike protein processing is different from that reported in other coronaviruses. Hypotheses to explain the differential activity of the inhibitor with different cell types are discussed.

scholarly journals Exoerythrocytic Plasmodium Parasites Secrete a Cysteine Protease Inhibitor Involved in Sporozoite Invasion and Capable of Blocking Cell Death of Host Hepatocytes

2010 ◽  
Vol 6 (3) ◽  
pp. e1000825 ◽  
Author(s):  
Annika Rennenberg ◽  
Christine Lehmann ◽  
Anna Heitmann ◽  
Tina Witt ◽  
Guido Hansen ◽  
...  
Keyword(s):  
Cell Death ◽  
Protease Inhibitor ◽  
Cysteine Protease ◽  
Cysteine Protease Inhibitor

scholarly journals Cysteine Protease Inhibitor (AcStefin) Is Required for Complete Cyst Formation of Acanthamoeba

2013 ◽  
Vol 12 (4) ◽  
pp. 567-574 ◽  
Author(s):  
Jung-Yub Lee ◽  
Su-Min Song ◽  
Eun-Kyung Moon ◽  
Yu-Ran Lee ◽  
Bijay Kumar Jha ◽  
...  
Keyword(s):  
Protease Inhibitor ◽  
Cysteine Protease ◽  
Protease Activity ◽  
Cathepsin L ◽  
Cyst Formation ◽  
Cysteine Proteases ◽  
Cysteine Protease Inhibitor ◽  
Content Type ◽  
Human Cathepsin ◽  
Interfering Rna

ABSTRACTThe encystation ofAcanthamoebaleads to the formation of resilient cysts from vegetative trophozoites. This process is essential for parasite survival under unfavorable conditions, such as those associated with starvation, low temperatures, and biocides. Furthermore, cysteine proteases have been implicated in the massive turnover of intracellular components required for encystation. Thus, strict modulation of the activities of cysteine proteases is required to protectAcanthamoebafrom intracellular damage. However, mechanisms underlying the control of protease activity during encystation have not been established inAcanthamoeba. In the present study, we identified and characterizedAcanthamoebacysteine protease inhibitor (AcStefin), which was found to be highly expressed during encystation and to be associated with lysosomes by fluorescence microscopy. Recombinant AcStefin inhibited various cysteine proteases, including human cathepsin B, human cathepsin L, and papain. Transfection with small interfering RNA against AcStefin increased cysteine protease activity during encystation and resulted in incomplete cyst formation, reduced excystation efficiency, and a significant reduction in cytoplasmic area. Taken together, these results indicate that AcStefin is involved in the modulation of cysteine proteases and that it plays an essential role during the encystation ofAcanthamoeba.

scholarly journals SERPINB3 (SCCA1) inhibits cathepsin L and lysoptosis, protecting cervical cancer cells from chemoradiation

2022 ◽  
Vol 5 (1) ◽  
Author(s):  
Songyan Wang ◽  
Cliff J. Luke ◽  
Stephen C. Pak ◽  
Victoria Shi ◽  
Liyun Chen ◽  
...  
Keyword(s):  
Cervical Cancer ◽  
Cell Death ◽  
Protease Inhibitor ◽  
Cancer Cells ◽  
Cathepsin L ◽  
Cysteine Protease Inhibitor ◽  
Knock Out ◽  
Lysosomal Protease ◽  
Cervical Cancer Cells ◽  
Radiation Induced

AbstractThe endogenous lysosomal cysteine protease inhibitor SERPINB3 (squamous cell carcinoma antigen 1, SCCA1) is elevated in patients with cervical cancer and other malignancies. High serum SERPINB3 is prognostic for recurrence and death following chemoradiation therapy. Cervical cancer cells genetically lacking SERPINB3 are more sensitive to ionizing radiation (IR), suggesting this protease inhibitor plays a role in therapeutic response. Here we demonstrate that SERPINB3-deficient cells have enhanced sensitivity to IR-induced cell death. Knock out of SERPINB3 sensitizes cells to a greater extent than cisplatin, the current standard of care. IR in SERPINB3 deficient cervical carcinoma cells induces predominantly necrotic cell death, with biochemical and cellular features of lysoptosis. Rescue with wild-type SERPINB3 or a reactive site loop mutant indicates that protease inhibitory activity is required to protect cervical tumor cells from radiation-induced death. Transcriptomics analysis of primary cervix tumor samples and genetic knock out demonstrates a role for the lysosomal protease cathepsin L in radiation-induced cell death in SERPINB3 knock-out cells. These data support targeting of SERPINB3 and lysoptosis to treat radioresistant cervical cancers.

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