scholarly journals Apoptin Causes Apoptosis in HepG-2 Cells by Inducing Stress Injury in the Endoplasmic Reticulum

2021 ◽  
Author(s):  
Yiquan Li ◽  
Bing Bai ◽  
Chao Shang ◽  
Jianan Cong ◽  
Jinbo Fang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Flow Cytometry ◽  
Endoplasmic Reticulum ◽  
Fluorescence Staining ◽  
Apoptotic Pathway ◽  
Mitochondrial Apoptotic Pathway ◽  
Expression Levels ◽  
Mitochondrial Injury ◽  
Induced Apoptosis

Abstract Apoptin is derived from the chicken anemia virus and exhibits specific cytotoxic effects against tumor cells. In our previous study, we demonstrated that Apoptin induced significant changes in the expression levels of endoplasmic reticulum stress (ERS) related proteins and caused a strong and lasting ERS response. The aim of this study was to explore the effects of ERS injury induced by Apoptin on the endoplasmic reticulum (ER) and the apoptotic pathway in mitochondria. ERS injury induced the intracellular levels of calcium (Ca2+) were determined by electron microscopy, flow cytometry and fluorescence staining. Mitochondrial injury was determined by mitochondrial membrane potential and electron microscopy. The relationship between Ca2+ level and mitochondrial injury on Apoptin-treating cells was analyzed using Ca2+ chelator, flow cytometry and fluorescence staining. Western blotting was used to investigate the levels of key proteins in the ER and the apoptotic pathway in mitochondria. We also investigated the in vivo effects of ERS injury on the ER and the mitochondrial apoptotic pathway via the immunohistochemical analysis of tumor tissues from HepG-2 cells acquired from nude mice undergoing xenografts. In vitro and in vivo experiments showed that Apoptin caused ERS injury and an imbalance in Ca2+, damaged the structure of the mitochondria, and increased the expression levels of Caspase-12, CHOP, AIF, HtrA2, Smac/Diablo, and Cyto-C. In summary, Apoptin induced apoptosis in HepG-2 cells via ERS and the mitochondrial apoptotic pathway. This study showed that Apoptin induced apoptosis in HepG-2 cells via ERS injury.

Glucocorticoid Therapy Targets Proliferation, Differentiation and Bcl-2 Dependent Survival Signaling in ALL Blasts.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 1841-1841
Author(s):  
Peter Rhein ◽  
Stefanie Scheid ◽  
Richard Ratei ◽  
Christian Hagemeier ◽  
Karl Seeger ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
Cell Lines ◽  
Induction Therapy ◽  
Molecular Mechanisms ◽  
Leukemia Cell ◽  
Apoptotic Pathway ◽  
Therapy Targets ◽  
Cell Cycling ◽  
Induced Apoptosis

Abstract In the multicentric ALL-BFM (Berlin-Frankfurt-Munster) study, all patients are uniformly treated during the first week of induction therapy which uses glucocorticoids (GC) as the principal therapeutic agent. The GC response assessed at day 8 of therapy provides one of the basic parameters for further risk stratification. In spite of the clinical significance, molecular mechanisms of GC action in vivo are largely unknown. Our recent genome-wide analysis of gene expression in blasts persisting during induction therapy identified a common set of genes differentially expressed in blasts at day 8 (d8) and at diagnosis (d0) (n=457, false discovery rate <0.05). Expression changes indicated therapy-induced inhibition of cell cycling, expression shift towards normal mature B cells and downregulation of the apoptosis regulator Bcl-2. In the current study, we validated the key differences between d8 and d0 blasts at protein and cellular levels. DNA distribution and percentage of cycling blasts was determined by flow cytometry in a series of matched d8 and d0 samples (13 pts) and demonstrated the decreased proliferative activity of d8 cells (4.3-fold, p=0.014). Protein expression, investigated by flow cytometry in a total of 84 pts, demonstrated statistically significant expression decrease of the progenitor cell antigenes CD10, CD34 and TdT and expression increase of the B-cell antigene CD20 and the inflammatory response molecules CD11b and IFNGR1 (p<0.05). We were also able to confirm the lower expression values of the Bcl-2 protein in d8 blasts (p<0.05, n=57). Investigation of GC-sensitive B-lineage leukemia cell lines demonstrated that BCL-2 downregulation by GC was a pre-requisite of GC-induced apoptosis. Moreover, we found a considerable cross-correlation between viability, cell cycling and Bcl-2 expression levels. Upregulation of the Bcl-2 expression via IL-7 receptor signaling prevented GC-induced apoptosis in these cell lines. Collectively, GC therapy interferes with differentiation and proliferation programs in leukemic blasts which are closely related to the Bcl-2 specific apoptotic pathway.

scholarly journals BCL-2 family member BOK promotes apoptosis in response to endoplasmic reticulum stress

2015 ◽  
Vol 112 (23) ◽  
pp. 7201-7206 ◽  
Author(s):  
Marcos A. Carpio ◽  
Michael Michaud ◽  
Wenping Zhou ◽  
Jill K. Fisher ◽  
Loren D. Walensky ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Er Stress ◽  
Brefeldin A ◽  
B Cell Lymphoma ◽  
Apoptotic Response ◽  
Apoptotic Pathway ◽  
Multiple Organs ◽  
Induced Apoptosis ◽  
The Unfolded Protein Response

B-cell lymphoma 2 (BCL-2) ovarian killer (BOK) is a BCL-2 family protein with high homology to the multidomain proapoptotic proteins BAX and BAK, yet Bok−/− and even Bax−/−Bok−/− and Bak−/−Bok−/− mice were reported to have no overt phenotype or apoptotic defects in response to a host of classical stress stimuli. These surprising findings were interpreted to reflect functional compensation among the BAX, BAK, and BOK proteins. However, BOK cannot compensate for the severe apoptotic defects of Bax−/−Bak−/− mice despite its widespread expression. Here, we independently developed Bok−/− mice and found that Bok−/− cells are selectively defective in their response to endoplasmic reticulum (ER) stress stimuli, consistent with the predominant subcellular localization of BOK at the ER. Whereas Bok−/− mouse embryonic fibroblasts exposed to thapsigargin, A23187, brefeldin A, DTT, geldanamycin, or bortezomib manifested reduced activation of the mitochondrial apoptotic pathway, the death response to other stimuli such as etoposide, staurosporine, or UV remained fully intact. Multiple organs in Bok−/− mice exhibited resistance to thapsigargin-induced apoptosis in vivo. Although the ER stress agents activated the unfolded protein response, both ATF4 and CHOP activation were diminished in Bok−/− cells and mice. Importantly, BAX and BAK were unable to compensate for the defective apoptotic response to ER stress observed in SV40-transformed and primary Bok−/− cells, and in vivo. These findings support a selective and distinguishing role for BOK in regulating the apoptotic response to ER stress, revealing—to our knowledge—the first bona fide apoptotic defect linked to Bok deletion.

MicroRNA-15b enhances hypoxia/reoxygenation-induced apoptosis of cardiomyocytes via a mitochondrial apoptotic pathway

APOPTOSIS ◽  
2013 ◽  
Vol 19 (1) ◽  
pp. 19-29 ◽  
Author(s):  
Lifeng Liu ◽  
Guoming Zhang ◽  
Zhuo Liang ◽  
Xiuhua Liu ◽  
Tiande Li ◽  
...  
Keyword(s):  
Apoptotic Pathway ◽  
Mitochondrial Apoptotic Pathway ◽  
Induced Apoptosis ◽  
Hypoxia Reoxygenation

scholarly journals AN ANALYSIS OF COLLAGEN SECRETION BY ESTABLISHED MOUSE FIBROBLAST LINES

1964 ◽  
Vol 22 (1) ◽  
pp. 227-258 ◽  
Author(s):  
Burton Goldberg ◽  
Howard Green
Keyword(s):  
Electron Microscopy ◽  
Endoplasmic Reticulum ◽  
Mouse Fibroblast ◽  
In Vivo Studies ◽  
In Vitro Synthesis ◽  
Collagen Secretion ◽  
Golgi System ◽  
Alternative Theories

In vitro synthesis of collagen by established mouse fibroblast lines has been examined by electron microscopy. During rapid growth (log phase), when collagen could not be detected in the cultures, the cells lacked a well developed granular ergastoplasm and Golgi system. Upon cessation of growth (stationary phase), collagen accumulated in the cultures and the cells demonstrated highly developed granular and smooth ergastoplasm. Collagen appeared to be synthesized in the rough-surfaced endoplasmic reticulum and to be transported as a soluble protein to the cell surface by vesicular elements of the agranular ergastoplasm. Fusion of the limiting membranes of these vesicles with the cell membrane permitted the discharge of the soluble collagen into the extracellular space, where fibrils of two diameter distributions formed. The secretion of collagen is concluded to be of the merocrine type. Alternative theories of collagen secretion are discussed and the data for established lines compared with the results of other in vitro and in vivo studies of collagen fibrillogenesis.

scholarly journals Apigenin Suppresses Angiogenesis by Inhibiting Tube Formation and Inducing Apoptosis

2016 ◽  
Vol 11 (10) ◽  
pp. 1934578X1601101
Author(s):  
Hyun Ju Kim ◽  
Mok-Ryeon Ahn
Keyword(s):  
Umbilical Vein ◽  
Chorioallantoic Membrane ◽  
Tube Formation ◽  
Anticancer Activities ◽  
Apoptotic Pathway ◽  
Inhibition Of Angiogenesis ◽  
Induced Apoptosis ◽  
Umbilical Vein Endothelial Cells

Apigenin has been reported to exert angiogenic and anticancer activities in vitro. The mechanism of inhibition of angiogenesis by apigenin, however, has not been well-established. In this study, we investigated whether apigenin not only inhibited tube formation but also induced apoptosis in human umbilical vein endothelial cells (HUVECs). Furthermore, strong antiangiogenic activity of apigenin was observed in the in vivo assay using chick embryo chorioallantoic membrane (CAM). We also analyzed changes in survival signals and the apoptotic pathway through Western blotting. The results indicate that apigenin exerts its antiangiogenic effects through induction of endothelial apoptosis.

scholarly journals C-phycocyanin from Limnothrix Species KNUA002 Alleviates Cisplatin-Induced Ototoxicity by Blocking the Mitochondrial Apoptotic Pathway in Auditory Cells

Marine Drugs ◽  
2019 ◽  
Vol 17 (4) ◽  
pp. 235 ◽  
Author(s):  
Ye-Ri Kim ◽  
Jeong-Mi Do ◽  
Kyung Hee Kim ◽  
Alexandra R. Stoica ◽  
Seung-Woo Jo ◽  
...  
Keyword(s):  
Organ Of Corti ◽  
Experimental Models ◽  
Common Side Effect ◽  
Anticancer Activities ◽  
Apoptotic Pathway ◽  
Mitochondrial Apoptotic Pathway ◽  
Anticancer Chemotherapy ◽  
Ros Accumulation

Ototoxicity, or adverse pharmacological effects on the inner ear or auditory nerve, is a common side effect of cisplatin, a platinum-based drug widely used in anticancer chemotherapy. Although the incidence of ototoxicity is high among patients that receive cisplatin therapy, there is currently no effective treatment for it. The generation of excessive reactive oxygen species (ROS) is considered to be the major cause of cisplatin-induced ototoxicity. C-phycocyanin (C-PC), a blue phycobiliprotein found in cyanobacteria and red algae, has antioxidant and anticancer activities in different experimental models in vitro and in vivo. Thus, we tested the ability of C-PC from Limnothrix sp. KNUA002 to protect auditory cells from cisplatin-induced ototoxicity in vitro. Pretreatment with C-PC from Limnothrix sp. KNUA002 inhibited apoptosis and protected mitochondrial function by preventing ROS accumulation in cisplatin-treated House Ear Institute-Organ of Corti 1 (HEI-OC1) cells, a mouse auditory cell line. Cisplatin increased the expression of Bax and reduced the expression of Bcl-2, which activate and inhibit, respectively, the mitochondrial apoptotic pathway in response to oxidative stress. Pretreatment with C-PC prior to cisplatin treatment caused the Bax and Bcl-2 levels to stay close to the levels in untreated control cells. Our results suggest that C-PC from Limnothrix sp. KNUA002 protects cells against cisplatin-induced cytotoxicity by inhibiting the mitochondrial apoptotic pathway.

Identification of apoptotic genes mediating TGF-β/Smad3-induced cell death in intestinal epithelial cells using a genomic approach

2007 ◽  
Vol 292 (1) ◽  
pp. G28-G38 ◽  
Author(s):  
Yanna Cao ◽  
Lu Chen ◽  
Weili Zhang ◽  
Yan Liu ◽  
Harry T. Papaconstantinou ◽  
...  
Keyword(s):  
Caspase 3 ◽  
Target Genes ◽  
Transforming Growth Factor ◽  
Intestinal Epithelial ◽  
Cytochrome C Release ◽  
Apoptotic Pathway ◽  
Genomic Approach ◽  
Apoptotic Genes ◽  
Induced Apoptosis

Transforming growth factor (TGF)-β-dependent apoptosis is important in the elimination of damaged or abnormal cells from normal tissues in vivo. Previously, we have shown that TGF-β inhibits the growth of rat intestinal epithelial (RIE)-1 cells. However, RIE-1 cells are relatively resistant to TGF-β-induced apoptosis due to a low endogenous Smad3-to-Akt ratio. Overexpression of Smad3 sensitizes RIE-1 cells (RIE-1/Smad3) to TGF-β-induced apoptosis by altering the Smad3-to-Akt ratio in favor of apoptosis. In this study, we utilized a genomic approach to identify potential downstream target genes that are regulated by TGF-β/Smad3. Total RNA samples were analyzed using Affymetrix oligonucleotide microarrays. We found that TGF-β regulated 518 probe sets corresponding to its target genes. Interestingly, among the known apoptotic genes included in the microarray analyses, only caspase-3 was induced, which was confirmed by real-time RT-PCR. Furthermore, TGF-β activated caspase-3 through protein cleavage. Upstream of caspase-3, TGF-β induced mitochondrial depolarization, cytochrome c release, and cleavage of caspase-9, which suggests that the intrinsic apoptotic pathway mediates TGF-β-induced apoptosis in RIE-1/Smad3 cells.

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