Faculty Opinions recommendation of Inhibition of MTOR disrupts autophagic flux in podocytes.

2012 ◽  
Author(s):  
Raymond Harris ◽  
Mingzhi Zhang
Keyword(s):  
Autophagic Flux

First Fluorescent Acetylspermidine Deacetylation Assay for HDAC10 Identifies Inhibitors of Neuroblastoma Cell Colony Growth That Increase Lysosome Accumulation

2020 ◽  
Author(s):  
Daniel Herp ◽  
Johannes Ridinger ◽  
Dina Robaa ◽  
Stephen A. Shinsky ◽  
Karin Schmidtkunz ◽  
...  
Keyword(s):  
Histone Deacetylases ◽  
High Throughput Screening ◽  
Neuroblastoma Cell ◽  
Hdac Inhibitors ◽  
Anticancer Therapy ◽  
Colony Growth ◽  
Autophagic Flux ◽  
Enzymatic Conversion ◽  
Lysine Deacetylase

Histone deacetylases (HDACs) are important epigenetic regulators involved in many diseases, esp. cancer. First HDAC inhibitors have been approved for anticancer therapy and many are in clinical trials. Among the 11 zinc-dependent HDACs, HDAC10 has received relatively little attention by drug discovery campaigns, despite its involvement e.g. in the pathogenesis of neuroblastoma. This is due in part to a lack of robust enzymatic conversion assays. In contrast to the protein lysine deacetylase and deacylase activity of the other HDAC subtypes, it has recently been shown that HDAC10 has strong preferences for deacetylation of oligoamine substrates like spermine or spermidine. Hence, it also termed a polyamine deacetylase (PDAC). Here, we present the first fluorescent enzymatic conversion assay for HDAC10 using an aminocoumarin labelled acetyl spermidine derivative to measure its PDAC activity, which is suitable for high-throughput screening. Using this assay, we identified potent inhibitors of HDAC10 mediated spermidine deacetylation in-vitro. Among those are potent inhibitors of neuroblastoma colony growth in culture that show accumulation of lysosomes, implicating disturbance of autophagic flux.

Gadolinium Oxide Nanoparticles Enhance the Cytotoxicity of Chemotherapeutic Drugs by Blocking Autophagic Flux in Human Ovarian Cancer Cells

2020 ◽  
Vol 16 ◽  
Author(s):  
Zhixiong Xie ◽  
Tianyu Zhang ◽  
Cheng Zhong
Keyword(s):  
Ovarian Cancer ◽  
Cancer Cells ◽  
Hela Cells ◽  
Late Stage ◽  
Ovarian Cancer Cells ◽  
Oxide Nanoparticles ◽  
Autophagic Flux ◽  
Human Ovarian Cancer ◽  
Chemotherapeutic Drugs ◽  
Chemotherapy Drugs

Background: During chemotherapy, drugs can damage cancer cells’ DNA and cytomembrane structure, and then induce cell death. However, autophagy can increase the chemotherapy resistance of cancer cells, reducing the effect of chemotherapy. Objective: To block the autophagic flux in cancer cells, it is vital to enhance the anti-cancer efficacy of chemotherapy drugs; for this purpose, we test the gadolinium oxide nanoparticles (Gd2O3 NPs)’ effect on autophagy. Methods: The cytotoxicity of Gd2O3 NPs on HeLa cells was evaluated by a (4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Then, monodasylcadaverine staining, immunofluorescence, immunoblot and apoptosis assay were conducted to evaluate the effect of Gd2O3 NPs on autophagy and efficacy of chemotherapy drugs in human ovarian cancer cells. Results: We found that Gd2O3 NPs, which have great potential for use as a contrast agent in magnetic resonance imaging, could block the late stage of autophagic flux in a dose-dependent manner and then cause autophagosome accumulation in HeLa cells. When co-treated with 8 μg/mL Gd2O3 NPs and 5 μg/mL cisplatin, the number of dead HeLa cells increased by about 20% compared with cisplatin alone. We observed the same phenomenon in cisplatin-resistant COC1/DDP cells. Conclusion: We conclude that Gd2O3 NPs can block the late stage of autophagic flux and enhance the cytotoxicity of chemotherapeutic drugs in human ovarian cancer cells. Thus, the nanoparticles have significant potential for use in both diagnosis and therapy of solid tumor.

Phanginin R Induces Cytoprotective Autophagy via JNK/c-Jun Signaling Pathway in Non-Small Cell Lung Cancer A549 Cells

2020 ◽  
Vol 20 (8) ◽  
pp. 982-988 ◽  
Author(s):  
Le-Le Zhang ◽  
Han Bao ◽  
Yu-Lian Xu ◽  
Xiao-Ming Jiang ◽  
Wei Li ◽  
...  
Keyword(s):  
Lung Cancer ◽  
Small Cell Lung Cancer ◽  
Signaling Pathway ◽  
Cell Lung Cancer ◽  
Biological Activities ◽  
A549 Cells ◽  
Immunofluorescence Assay ◽  
Small Cell ◽  
Autophagic Flux ◽  
Small Cell Lung

Background: Cassane-type diterpenoids are widely distributed in the medical plants of genus Caesalpinia. To date, plenty of cassane diterpenoids have been isolated from the genus Caesalpinia, and some of them were documented to exhibit multiple biological activities. However, the effects of these compounds on autophagy have never been reported. Objective: To investigate the effects and mechanisms of the cassane diterpenoids including Phanginin R (PR) on autophagy in Non-Small Cell Lung Cancer (NSCLC) A549 cells. Methods: Western blot analysis and immunofluorescence assay were performed to investigate the effects of the compounds on autophagic flux in A549 cells. The pathway inhibitor and siRNA interference were used to investigate the mechanism of PR. MTT assay was performed to detect cell viability. Results: PR treatment upregulated the expression of phosphatidylethanolamine-modified microtubule-associated protein Light-Chain 3 (LC3-II) in A549 cells. Immunofluorescence assay showed that PR treatment increased the production of red-fluorescent puncta in mRFP-GFP-LC3 plasmid-transfected cells, indicating PR promoted autophagic flux in A549 cells. PR treatment activated the c-Jun N-terminal Kinase (JNK) signaling pathway while it did not affect the classical Akt/mammalian Target of Rapamycin (mTOR) pathway. Pretreatment with the JNK inhibitor SP600125 or siRNA targeting JNK or c-Jun suppressed PR-induced autophagy. In addition, cotreatment with the autophagy inhibitor Chloroquine (CQ) or inhibition of the JNK/c-Jun signaling pathway increased PR-induced cytotoxicity. Conclusion: PR induced cytoprotective autophagy in NSCLC A549 cells via the JNK/c-Jun signaling pathway, and autophagy inhibition could further improve the anti-cancer potential of PR.

TNF-α Suppresses Autophagic Flux in Acinar Cells in IgG4-Related Sialadenitis

2019 ◽  
Vol 98 (12) ◽  
pp. 1386-1396 ◽  
Author(s):  
X. Hong ◽  
S.N. Min ◽  
Y.Y. Zhang ◽  
Y.T. Lin ◽  
F. Wang ◽  
...  
Keyword(s):  
Acinar Cell ◽  
Cell Injury ◽  
Ex Vivo ◽  
Secretory Granules ◽  
Acinar Cells ◽  
Autophagic Flux ◽  
C6 Cells ◽  
Tnf Α ◽  
Α Level

IgG4-related sialadenitis (IgG4-RS) is a newly recognized immune-mediated systemic fibroinflammatory disease that affects salivary glands and leads to hyposalivation. Tumor necrosis factor–α (TNF-α) is a critical proinflammatory cytokine involved in several salivary gland disorders, but its role and mechanism regarding acinar cell injury in IgG4-RS are unknown. Here, we found that TNF-α level was significantly increased in serum and submandibular gland (SMG) of patients and that serum TNF-α level was negatively correlated with saliva flow rate. Ultrastructural observations of IgG4-RS SMGs revealed accumulation of large autophagic vacuoles, as well as dense fibrous bundles, decreased secretory granules, widened intercellular spaces, swollen mitochondria, and expanded endoplasmic reticulum. Expression levels of LC3 and p62 were both increased in patients’ SMGs. TNF-α treatment led to elevated levels of LC3II and p62 in both SMG-C6 cells and cultured human SMG tissues but did not further increase their levels when combined with bafilomycin A1 treatment. Moreover, transfection of Ad-mCherry-GFP-LC3B in SMG-C6 cells confirmed the suppression of autophagic flux after TNF-α treatment. Immunofluorescence imaging revealed that costaining of LC3 and the lysosomal marker LAMP2 was significantly decreased in patients, TNF-α–treated SMG-C6 cells, and cultured human SMGs, indicating a reduction in autophagosome-lysosome fusion. Furthermore, the ratio of pro/mature cathepsin D was elevated in vivo, ex vivo, and in vitro. TNF-α also appeared to induce abnormal acidification of lysosomes in acinar cells, as assessed by lysosomal pH and LysoTracker DND-26 fluorescence intensity. In addition, TNF-α treatment induced transcription factor EB (TFEB) redistribution in SMG-C6 cells, which was consistent with the changes observed in IgG4-RS patients. TNF-α increased the phosphorylation of extracellular signal–regulated kinase (ERK) 1/2, and inhibition of ERK1/2 by U0126 reversed TNF-α–induced TFEB redistribution, lysosomal dysfunction, and autophagic flux suppression. These findings suggest that TNF-α is a key cytokine related to acinar cell injury in IgG4-RS through ERK1/2-mediated autophagic flux suppression.

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