scholarly journals An acid protease secreted by transformed cells interferes with antigen processing.

1988 ◽  
Vol 106 (6) ◽  
pp. 1879-1884 ◽  
Author(s):  
K McCoy ◽  
S Gal ◽  
R H Schwartz ◽  
M M Gottesman
Keyword(s):  
Cytochrome C ◽  
Antigen Processing ◽  
Cathepsin L ◽  
Chinese Hamster ◽  
Acid Protease ◽  
Transformed Cells ◽  
Gene Products ◽  
Major Histocompatability Complex ◽  
Tumor Bearing ◽  
Acidic Compartment

The major excreted protein of malignantly transformed mouse fibroblasts (MEP), which is the precursor to lysosomal cathepsin L, was used to study the effect of exogenous acid proteases on antigen processing. When MEP and native pigeon cytochrome c were added to Chinese hamster ovary (CHO) cells expressing transfected major histocompatability complex class II gene products, the antigen-specific T-cell hybridoma 2B4 did not respond to the antigen. MEP appears to destroy the antigen in an acid compartment of the presenting cell because: (a) MEP is only active as a protease under acid conditions; (b) mannose 6-phosphate inhibited the internalization of MEP and blocked its effect on antigen processing; (c) the destruction required the simultaneous entry of the antigen and MEP into the cells; and (d) cytochrome c fragment 66-104 which does not need to be processed stimulated 2B4 in the presence of MEP. These results support the hypothesis that antigen processing requires internalization of the antigen into an acidic compartment, and they provide a new model for the investigation of the contribution of acid proteases to the reduced immunocompetence of tumor-bearing animals.

scholarly journals Quinacrine-Induced Autophagy in Ovarian Cancer Triggers Cathepsin-L Mediated Lysosomal/Mitochondrial Membrane Permeabilization and Cell Death

Cancers ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 2004
Author(s):  
Prabhu Thirusangu ◽  
Christopher L. Pathoulas ◽  
Upasana Ray ◽  
Yinan Xiao ◽  
Julie Staub ◽  
...  
Keyword(s):  
Ovarian Cancer ◽  
Cell Death ◽  
Cytochrome C ◽  
Cancer Cells ◽  
Apoptotic Cell ◽  
Cathepsin L ◽  
Membrane Permeabilization ◽  
Apoptotic Cell Death ◽  
Ovarian Cancer Cells ◽  
Autophagic Flux

We previously reported that the antimalarial compound quinacrine (QC) induces autophagy in ovarian cancer cells. In the current study, we uncovered that QC significantly upregulates cathepsin L (CTSL) but not cathepsin B and D levels, implicating the specific role of CTSL in promoting QC-induced autophagic flux and apoptotic cell death in OC cells. Using a Magic Red® cathepsin L activity assay and LysoTracker red, we discerned that QC-induced CTSL activation promotes lysosomal membrane permeability (LMP) resulting in the release of active CTSL into the cytosol to promote apoptotic cell death. We found that QC-induced LMP and CTSL activation promotes Bid cleavage, mitochondrial outer membrane permeabilization (MOMP), and mitochondrial cytochrome-c release. Genetic (shRNA) and pharmacological (Z-FY(tBU)-DMK) inhibition of CTSL markedly reduces QC-induced autophagy, LMP, MOMP, apoptosis, and cell death; whereas induced overexpression of CTSL in ovarian cancer cell lines has an opposite effect. Using recombinant CTSL, we identified p62/SQSTM1 as a novel substrate of CTSL, suggesting that CTSL promotes QC-induced autophagic flux. CTSL activation is specific to QC-induced autophagy since no CTSL activation is seen in ATG5 knockout cells or with the anti-malarial autophagy-inhibiting drug chloroquine. Importantly, we showed that upregulation of CTSL in QC-treated HeyA8MDR xenografts corresponds with attenuation of p62, upregulation of LC3BII, cytochrome-c, tBid, cleaved PARP, and caspase3. Taken together, the data suggest that QC-induced autophagy and CTSL upregulation promote a positive feedback loop leading to excessive autophagic flux, LMP, and MOMP to promote QC-induced cell death in ovarian cancer cells.

scholarly journals Loss of thrombospondin transcriptional activity in nickel-transformed cells.

1994 ◽  
Vol 14 (1) ◽  
pp. 851-858 ◽  
Author(s):  
K Salnikow ◽  
S Cosentino ◽  
C Klein ◽  
M Costa
Keyword(s):  
Chinese Hamster ◽  
Restriction Enzymes ◽  
Cell Types ◽  
Suppressor Gene ◽  
Transformed Cells ◽  
Normal Cells ◽  
Nickel Compounds ◽  
Embryo Cells ◽  
Rb Gene

mRNA from normal Chinese hamster embryo (CHE) cells was transcribed to cDNA and subtracted with an excess of mRNA from Chinese hamster embryo cells transformed by nickel compounds. Here we report the recovery of a sequence found to be highly homologous to the mouse thrombospondin 1 gene that was obtained by this subtraction procedure. Since thrombospondin is antiangiogenic, cancer cells expressing high levels of thrombospondin cannot grow in vivo because capillaries will not proliferate to cells secreting thrombospondin. To examine expression of thrombospondin, normal CHE cells were stained with monoclonal antibodies to human thrombospondin. The protein was present abundantly in the cytoplasm of normal cells but at greatly reduced levels in Ni-transformed cells. Analysis of mRNA by Northern (RNA) blot revealed transcripts in normal cells but little thrombospondin mRNA in Ni-transformed cells. Loss of thrombospondin mRNA expression was related to Ni treatment rather than transformation, since Ni-resistant cells also exhibited fewer thrombospondin transcripts than did wild-type cells. Digestion of genomic DNA with various combinations of restriction enzymes revealed thrombospondin gene patterns that were identical in both cell types, suggesting that there were no major deletions or rearrangements of the gene in the nickel-transformed cells. The inactivation of the thrombospondin gene was further investigated by analyzing the promoter activity of this gene linked to a chloramphenicol acetyltransferase (CAT) reporter plasmid that was transfected into normal and Ni-transformed cells. The CAT activity in normal cells was significantly higher than in Ni-transformed cells, suggesting that the promoter region of thrombospondin was less efficiently transcribed in Ni-transformed cells. We studied the consequences of enhanced expression of the retinoblastoma (Rb) gene, a known tumor suppressor gene, on CAT transcription driven by the human thrombospondin promoter. Cotransfection of an expression vector containing the mouse Rb gene greatly enhanced the transcription from the thrombospondin promoter such that the expression was higher in normal cells than in transformed cells.

scholarly journals Cathepsin L in COVID-19: From Pharmacological Evidences to Genetics

2020 ◽  
Vol 10 ◽  
Author(s):  
Caio P. Gomes ◽  
Danilo E. Fernandes ◽  
Fernanda Casimiro ◽  
Gustavo F. da Mata ◽  
Michelle T. Passos ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Antigen Processing ◽  
Cathepsin L ◽  
Modern Science ◽  
Immunological Response ◽  
Multiple Organ ◽  
Bone Diseases ◽  
Host Cells ◽  
Matrix Remodeling ◽  
Inflammatory Status

The coronavirus disease 2019 (COVID-19) pandemics is a challenge without precedent for the modern science. Acute Respiratory Discomfort Syndrome (ARDS) is the most common immunopathological event in SARS-CoV-2, SARS-CoV, and MERS-CoV infections. Fast lung deterioration results of cytokine storm determined by a robust immunological response leading to ARDS and multiple organ failure. Here, we show cysteine protease Cathepsin L (CatL) involvement with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and COVID-19 from different points of view. CatL is a lysosomal enzyme that participates in numerous physiological processes, including apoptosis, antigen processing, and extracellular matrix remodeling. CatL is implicated in pathological conditions like invasion and metastasis of tumors, inflammatory status, atherosclerosis, renal disease, diabetes, bone diseases, viral infection, and other diseases. CatL expression is up-regulated during chronic inflammation and is involved in degrading extracellular matrix, an important process for SARS-CoV-2 to enter host cells. In addition, CatL is probably involved in processing SARS-CoV-2 spike protein. As its inhibition is detrimental to SARS-CoV-2 infection and possibly exit from cells during late stages of infection, CatL could have been considered a valuable therapeutic target. Therefore, we describe here some drugs already in the market with potential CatL inhibiting capacity that could be used to treat COVID-19 patients. In addition, we discuss the possible role of host genetics in the etiology and spreading of the disease.

scholarly journals Fuzheng Qingjie Granules Inhibit Growth of Hepatoma Cells via Inducing Mitochondria-Mediated Apoptosis and Enhancing Immune Function

2016 ◽  
Vol 16 (3) ◽  
pp. 329-338 ◽  
Author(s):  
Xuzheng Chen ◽  
Zhiyun Cao ◽  
Youquan Zhang ◽  
Jinnong Li ◽  
Suqing Wang ◽  
...  
Keyword(s):  
T Cells ◽  
Cytochrome C ◽  
Immune Function ◽  
Nk Cells ◽  
Hepg2 Cells ◽  
Caspase 3 ◽  
Tumor Tissue ◽  
Hepatoma Cells ◽  
Tumor Bearing ◽  
Tnf Α

Fuzheng Qingjie (FZQJ) granules, a compound Chinese medicine, have been used as an adjuvant therapy for alimentary tract cancers. However, the underlying anticancer mechanisms are still not well understood. In the present study, HepG2 cells were treated with FZQJ-containing serum. Cell proliferation was evaluated using MTT assay. Apoptosis was analyzed using a flow cytometer. Cell ultrastructure was observed under a transmission electron microscope. The mitochondrial membrane potential (Δψ) was examined with JC-1 dye. In H22 tumor–bearing mice, CD4+ T cells, CD8+ T cells, CD3+ T cells, and natural killer (NK) cells in peripheral blood were evaluated cytometrically. Interleukin (IL)-2 and tumor necrosis factor (TNF)-α levels were measured using radioimmunoassay.The mRNA levels of Bax and Bcl-2 were examined by reverse transcription–polymerase chain reaction. The protein levels of Bax, Bcl-2, cytochrome C, caspase 3 and 9, PARP, and CD69 were examined by Western blotting. The apoptotic cells in tissues were observed using TUNEL method. Alanine transaminase (ALT), aspartate transaminase (AST), blood urea nitrogen (BUN), and creatinine (CRE) were detected by an automatic biochemical analyzer. The results showed that FZQJ-containing serum remarkably inhibited proliferation of HepG2 cells in dose- and time-dependent manners, induced HepG2 cell apoptosis and caused a decrease of Δψ. Analysis of tumor tissue showed that FZQJ-induced apoptosis was accompanied by downregulation of Bcl-2 and upregulation of Bax, release of cytochrome c, activation of caspase 3 and 9, and cleavage of PARP. In addition, FZQJ increased the percentages of CD4+ T and NK cells, the ratio of CD4+/CD8+ T cells as well as the levels of serum TNF-α. FZQJ also increased CD69 expression in tumor tissue. No hepatorenal toxicity was observed in H22 tumor–bearing mice. These results indicated that FZQJ could inhibit the growth of hepatoma cells via regulating immune function and inducing mitochondria mediated apoptosis.

scholarly journals LMP-associated proteolytic activities and TAP-dependent peptide transport for class 1 MHC molecules are suppressed in cell lines transformed by the highly oncogenic adenovirus 12.

1996 ◽  
Vol 183 (2) ◽  
pp. 499-514 ◽  
Author(s):  
R Rotem-Yehudar ◽  
M Groettrup ◽  
A Soza ◽  
P M Kloetzel ◽  
R Ehrlich
Keyword(s):  
Antigen Processing ◽  
Regulatory Elements ◽  
Class I ◽  
Peptide Transport ◽  
Cell Surface Expression ◽  
Transformed Cells ◽  
Recombinant Vaccinia ◽  
Mhc Molecules ◽  
Vaccinia Viruses ◽  
Proteolytic Activities

Expression of class I major histocompatibility complex antigens on the surface of cells transformed by adenovirus 12 (Ad12) is generally very low, and correlates with the in vivo oncogenicity of this virus. In primary embryonal fibroblasts (H-2b) that express transgenic swine class I antigen (PD1), Ad12-mediated transformation results in inhibition in transport of newly synthesized class I molecules, as well as significant reduction in transporter associated with antigen presentation (TAP) gene expression. In this report we show that reexpression of TAP molecules either by stable transfection of mouse TAP genes or by infection with recombinant vaccinia viruses expressing human TAP genes, only partially reconstitutes the expression and transport of the class I molecules. Further analysis of Ad12-transformed cells revealed that the expression of both LMP2 and LMP7, but not of other proteasome complex components, was downregulated, resulting in altered proteolytic activities of the 20S proteasomes. Reconstitution of both TAP and LMP expression resulted in complete restoration of PD1 cell surface expression and enhanced expression of the endogenous H-2D(b) molecules encoded by recombinant vaccinia viruses, in reconstituted Ad12-transformed cells, efficient transport of H-2 class I molecules could only be achieved by treatment of the cells with gamma-interferon. These data suggest that an additional factor(s) that is interferon-regulated plays a role in the biosynthetic pathway of the class I complex, and that its function is deficient in this cell system. Thus, Ad12 viral transformation appears to suppress the expression of multiple genes that are important for antigen processing and presentation, which allows such transformed cells to escape immune surveillance. This coordinate downregulation of immune response genes must likely occur through their use of common regulatory elements.

scholarly journals HIV-1–infected dendritic cells show 2 phases of gene expression changes, with lysosomal enzyme activity decreased during the second phase

Blood ◽  
2009 ◽  
Vol 114 (1) ◽  
pp. 85-94 ◽  
Author(s):  
Andrew N. Harman ◽  
Marianne Kraus ◽  
Chris R. Bye ◽  
Karen Byth ◽  
Stuart G. Turville ◽  
...  
Keyword(s):  
Gene Expression ◽  
Dendritic Cells ◽  
Antigen Processing ◽  
De Novo ◽  
Cathepsin L ◽  
Transcriptional Response ◽  
Differentially Expressed ◽  
Second Phase ◽  
Genes Encoding ◽  
Hiv 1

AbstractDendritic cells (DCs) play a key role in the pathogenesis of HIV infection. HIV interacts with these cells through 2 pathways in 2 temporal phases, initially via endocytosis and then via de novo replication. Here the transcriptional response of human DCs to HIV-1 was studied in these phases and at different stages of the virus replication cycle using purified HIV-1 envelope proteins, and inactivated and viable HIV-1. No differential gene expression was detected in response to envelope. However, more than 100 genes were differentially expressed in response to entry of viable and inactivated HIV-1 in the first phase. A completely different set of genes was differentially expressed in the second phase, predominantly in response to viable HIV-1, including up-regulation of immune regulation genes, whereas genes encoding lysosomal enzymes were down-regulated. Cathepsins B, C, S, and Z RNA and protein decreased, whereas cathepsin L was increased, probably reflecting a concomitant decrease in cystatin C. The net effect was markedly diminished cathepsin activity likely to result in enhanced HIV-1 survival and transfer to contacting T lymphocytes but decreased HIV-1 antigen processing and presentation to these T cells.

scholarly journals Presentation of numerous viral peptides to mouse major histocompatibility complex (MHC) class I-restricted T lymphocytes is mediated by the human MHC-encoded transporter or by a hybrid mouse-human transporter.

1993 ◽  
Vol 177 (6) ◽  
pp. 1785-1790 ◽  
Author(s):  
J W Yewdell ◽  
F Esquivel ◽  
D Arnold ◽  
T Spies ◽  
L C Eisenlohr ◽  
...  
Keyword(s):  
T Cells ◽  
Major Histocompatibility Complex ◽  
Antigen Processing ◽  
Class I ◽  
Gene Products ◽  
Major Histocompatibility ◽  
Mouse Major Histocompatibility Complex ◽  
Histocompatibility Complex ◽  
Functional Complex ◽  
Human And Mouse

The major histocompatibility complex-encoded transporter associated with antigen processing (TAP) is required for the efficient presentation of cytosolic antigens to class I-restricted T cells. TAP is thought to be formed by the interaction of two gene products, termed TAP1 and TAP2. We find that TAPs consisting either of human subunits, or mouse TAP1 and human TAP2, facilitate the presentation of numerous defined viral peptides to mouse class I-restricted T cells. As human and mouse TAP2 and TAP1 differ in 23 and 28% of their residues, respectively, this indicates that TAP1 and TAP2 can form a functional complex with partners considerably different from those they coevolved with. Moreover, these findings indicate that widely disparate TAPs facilitate delivery of the same peptides to class I molecules. These findings suggest that TAP polymorphism does not greatly influence the types of peptides presented to the immune system.

scholarly journals Adenovirus type 5 E1A gene products act as transformation suppressors of the neu oncogene.

1991 ◽  
Vol 11 (3) ◽  
pp. 1745-1750 ◽  
Author(s):  
D H Yu ◽  
K Scorsone ◽  
M C Hung
Keyword(s):  
Nude Mice ◽  
Adenovirus Type ◽  
Transformed Cells ◽  
Gene Products ◽  
Early Region ◽  
Transforming Activity ◽  
Neu Oncogene ◽  
E1a Gene ◽  
Adenovirus Type 5

The adenovirus type 5 early region 1A (E1A) gene was introduced into neu-transformed B104-1-1 cells. Cells that expressed E1A possessed reduced transforming activity in vitro and reduced tumorigenicity in nude mice. These results demonstrate that the E1A gene products can act negatively to suppress the transformed phenotype in neu-transformed cells.

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