Tocotrienol-induced cytotoxicity is unrelated to mitochondrial stress apoptotic signaling in neoplastic mammary epithelial cells

2005 ◽  
Vol 83 (1) ◽  
pp. 86-95 ◽  
Author(s):  
Sumit J Shah ◽  
Paul W Sylvester
Keyword(s):  
Epithelial Cells ◽  
Mitochondrial Membrane ◽  
Mammary Epithelial Cells ◽  
Flow Cytometric Analysis ◽  
Mammary Epithelial ◽  
Mitochondrial Stress ◽  
Apoptotic Signaling ◽  
Flow Cytometric ◽  
Apoptotic Proteins ◽  
Induced Apoptosis

Tocotrienols and tocopherols represent the 2 subgroups within the vitamin E family of compounds, but tocotrienols display significantly greater apoptotic activity against a variety of cancer cell types. However, the exact mechanism mediating tocotrienol-induced apoptosis is not understood. Studies were conducted to determine the effects of tocotrienols on mitochondrial-stress-mediated apoptotic signaling in neoplastic +SA mammary epithelial cells grown in vitro. Exposure for 24 h to 0–20 µmol/L γ-tocotrienol resulted in a dose–responsive increase in +SA cells undergoing apoptosis, as determined by flow cytometric analysis of Annexin V staining. However, tocotrienol-induced apoptosis was not associated with a disruption or loss of mitochondrial membrane potential, or the release of mitochondrial cytochrome c into the cytoplasm, as determined by JC-1 flow cytometric staining and ELISA assay, respectively. Interestingly, apoptotic +SA cells showed a paradoxical decrease in mitochondrial levels of pro-apoptotic proteins Bid, Bax, and Bad, and a corresponding increase in mitochondrial levels of anti-apoptotic proteins, Bcl-2 and Bcl-xL, suggesting that mitochondrial membrane stability and integrity might actually be enhanced for a limited period of time following acute tocotrienol exposure. In summary, these findings clearly demonstrate that tocotrienol-induced apoptosis occurs independently of mitochondrial stress apoptotic signaling in neoplastic +SA mammary epithelial cells.Key words: breast cancer, tocotrienols, apoptosis, mitochondria, Bcl-2.

scholarly journals 5-ALA Attenuates the Palmitic Acid-Induced ER Stress and Apoptosis in Bovine Mammary Epithelial Cells

Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 1183
Author(s):  
Mst Mamuna Sharmin ◽  
Md Aminul Islam ◽  
Itsuki Yamamoto ◽  
Shin Taniguchi ◽  
Shinichi Yonekura
Keyword(s):  
T Cells ◽  
Epithelial Cells ◽  
Palmitic Acid ◽  
Er Stress ◽  
Aminolevulinic Acid ◽  
Mammary Epithelial Cells ◽  
Mammary Epithelial ◽  
Protective Effects ◽  
Bovine Mammary Epithelial Cells ◽  
Induced Apoptosis

The conservation of mammary gland physiology by maintaining the maximum number of mammary epithelial cells (MECs) is of the utmost importance for the optimum amount of milk production. In a state of negative energy balance, palmitic acid (PA) reduces the number of bovine MECs. However, there is no effective strategy against PA-induced apoptosis of MECs. In the present study, 5-aminolevulinic acid (5-ALA) was established as a remedial agent against PA-induced apoptosis of MAC-T cells (an established line of bovine MECs). In PA-treated cells, the apoptosis-related genes BCL2 and BAX were down- and upregulated, respectively. The elevated expression of major genes of the unfolded protein response (UPR), such as CHOP, a proapoptotic marker (C/EBP homologous protein), reduced the viability of PA-treated MAC-T cells. In contrast, 5-ALA pretreatment increased and decreased BCL2 and BAX expression, respectively. Moreover, cleaved caspase-3 protein expression was significantly reduced in the 5-ALA-pretreated group in comparison with the PA group. The downregulation of major UPR-related genes, including CHOP, extended the viability of MAC-T cells pretreated with 5-ALA and also reduced the enhanced intensity of the PA-induced expression of phospho-protein kinase R-like ER kinase. Moreover, the enhanced expression of HO-1 (antioxidant gene heme oxygenase) by 5-ALA reduced PA-induced oxidative stress (OxS). HO-1 is not only protective against OxS but also effective against ER stress. Collectively, these findings offer new insights into the protective effects of 5-ALA against PA-induced apoptosis of bovine MECs.

scholarly journals Keratin attenuates tumor necrosis factor–induced cytotoxicity through association with TRADD

2001 ◽  
Vol 155 (3) ◽  
pp. 415-426 ◽  
Author(s):  
Hiroyasu Inada ◽  
Ichiro Izawa ◽  
Miwako Nishizawa ◽  
Eriko Fujita ◽  
Tohru Kiyono ◽  
...  
Keyword(s):  
Tumor Necrosis Factor ◽  
Epithelial Cells ◽  
Tumor Necrosis ◽  
Mammary Epithelial Cells ◽  
Mammary Epithelial ◽  
Type I ◽  
Death Domain ◽  
Interacting Protein ◽  
Induced Apoptosis ◽  
Necrosis Factor

Keratin 8 and 18 (K8/18) are the major components of intermediate filament (IF) proteins of simple or single-layered epithelia. Recent data show that normal and malignant epithelial cells deficient in K8/18 are nearly 100 times more sensitive to tumor necrosis factor (TNF)–induced cell death. We have now identified human TNF receptor type 1 (TNFR1)–associated death domain protein (TRADD) to be the K18-interacting protein. Among IF proteins tested in two-hybrid systems, TRADD specifically bound K18 and K14, type I (acidic) keratins. The COOH-terminal region of TRADD interacted with the coil Ia of the rod domain of K18. Endogenous TRADD coimmunoprecipitated with K18, and colocalized with K8/18 filaments in human mammary epithelial cells. Overexpression of the NH2 terminus (amino acids 1–270) of K18 containing the TRADD-binding domain as well as overexpression of K8/18 in SW13 cells, which are devoid of keratins, rendered the cells more resistant to killing by TNF. We also showed that overexpressed NH2 termini of K18 and K8/18 were associated with endogenous TRADD in SW13 cells, resulting in the inhibition of caspase-8 activation. These results indicate that K18 may sequester TRADD to attenuate interactions between TRADD and activated TNFR1 and moderate TNF-induced apoptosis in simple epithelial cells.

Heat-induced apoptosis and gene expression in bovine mammary epithelial cells

2016 ◽  
Vol 56 (5) ◽  
pp. 918 ◽  
Author(s):  
Han Hu ◽  
Jiaqi Wang ◽  
Haina Gao ◽  
Songli Li ◽  
Yangdong Zhang ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Cell Apoptosis ◽  
Stress Proteins ◽  
Mammary Epithelial Cells ◽  
Mammary Epithelial ◽  
Tumour Necrosis Factor Receptor ◽  
Bovine Mammary Epithelial Cells ◽  
Caspase 6 ◽  
Induced Apoptosis ◽  
Shock Proteins

The objective of this study was to identify the apoptosis and cell-defence response of bovine mammary epithelial cells under heat stress (HS). Cells were exposed to either 38°C or 42°C for 0.5, 1, 3, 5, 8, or 12 h, and the transcription of heat shock proteins (Hsps), Bcl-2 family, caspases and apoptosis-regulated genes were quantified by quantitative real-time polymerase chain reaction. Caspase-3, -7 and -8 were markedly upregulated by HS and the peak gene abundance appeared at 5 h. However, the same family numbers, caspase-6 and -9 were sustained downregulated in HS. The expression of anti-apoptotic gene Bcl-2, Bcl-2A and Mcl-1 increased sharply in HS but returned to pre-HS levels after 8 h. The pro-apoptotic genes: Bax, Bak and Bid were downregulated during HS. The striking changes of signalling factors of apoptosis: tumour necrosis factor receptor, p53, Apaf-1 was upregulated, and Fas was downregulated in HS. Stress proteins Hsp genes (hsp27, hsp70 and hsp90) were generally increased at 42°C and this was especially apparent for hsp70 transcription as it was increased 14-fold at 1 h. Simultaneously, HS induced cell apoptosis, and the peak of apoptosis rate appeared at 3 and 5 h, which were assessed by flow cytometry. Our results suggest that HS induces cell apoptosis, disturbs the normal biological activity, and aroused intracellular thermotolerance responses of bovine mammary epithelial cells.

scholarly journals Polydatin Protects Bovine Mammary Epithelial Cells against Zearalenone-Induced Apoptosis by Inhibiting Oxidative Responses and Endoplasmic Reticulum Stress

Toxins ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 121
Author(s):  
Yurong Fu ◽  
Yongcheng Jin ◽  
Anshan Shan ◽  
Jing Zhang ◽  
Hongyu Tang ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Treatment Group ◽  
Epithelial Cells ◽  
Er Stress ◽  
Cell Apoptosis ◽  
Mammary Epithelial Cells ◽  
Mammary Epithelial ◽  
Bovine Mammary Epithelial Cells ◽  
Stress Related Genes ◽  
Induced Apoptosis

Zearalenone (ZEA) is a mycotoxin of the Fusarium genus that can cause endoplasmic reticulum (ER) stress and Apoptosis in bovine mammary epithelial cells (MAC-T). Polydatin (PD), a glycoside purified from Polygonum cuspidatum, has antioxidant properties. This study aimed to explore whether PD can alleviate ZEA-induced damage on bovine mammary epithelial cells (MAC-T). We found that incasing the concentration of ZEA (0, 7.5, 15, 30, 60, 90, 120, and 240 μM) gradually decreased the cell viability. PD treatment alone at 5, 10, and 20 μM did not affect cell viability. Follow-up studies then applied 30 μM of ZEA and 5 μM of PD to treat cells; the results showed that the ZEA + PD treatment group effectively reduced cell oxidative damage compared with the ZEA treatment group. The qPCR analysis showed that ZEA treatment significantly up-regulated the expression of ER stress-related genes, relative to the control. However, adding PD significantly down-regulated the expression of ER stress-related genes. The cell apoptosis detection results showed that, compared with the ZEA treatment group, the ZEA + PD treatment group down-regulated the Bax gene and up-regulated the Bcl-2 gene expressions, which reduced the cell apoptosis rate and Caspase-3 activity. Taken together, these results indicate that PD reduces ZEA-induced apoptosis by inhibiting oxidative damage and ER stress.

Signaling and apoptosis differences between severe hypoxia and desferoxamine treatment of human epithelial cells

2008 ◽  
Vol 86 (5) ◽  
pp. 425-436 ◽  
Author(s):  
Adrian Harold Box ◽  
Carol Yuen ◽  
Dragana Ponjevic ◽  
Gordon H. Fick ◽  
Douglas James Demetrick
Keyword(s):  
Cell Cycle ◽  
Cell Death ◽  
Epithelial Cells ◽  
Cell Cycle Arrest ◽  
Cell Lines ◽  
Mammary Epithelial Cells ◽  
Mammary Epithelial ◽  
Severe Hypoxia ◽  
Cycle Arrest ◽  
Induced Apoptosis

The mechanisms by which cells undergo proliferation arrest or cell death in response to hypoxia are still not completely understood. Originally, we showed that HeLa and Hep3B carcinoma cells undergo different proliferation responses in hypoxia. We now show that these 2 cell lines also have different cell death responses to severe hypoxia, with HeLa showing both cell cycle arrest and apoptosis (as early as 12 h after hypoxia treatment), and Hep3B showing resistance to both. Hypoxia-induced apoptosis in Hela was associated with decreases of both phospho-S473- and -T308-AKT and loss of AKT function, whereas Hep3B cells were resistant to hypoxia-induced apoptosis and did not lose phospho-AKT or AKT function. We then decided to test if our observations were confirmed using a hypoxia mimic, desferoxamine. Desferoxamine treatment yielded cell cycle arrest in HeLa and moderate arrest in Hep3B but, surprisingly, did not induce notable apoptosis of either cell line with up to 24 h of treatment. Hypoxia-treated normal human mammary epithelial cells also showed hypoxia-induced apoptosis. Interestingly, in these cell lines, there was a complete correlation between loss of phospho-AKT and (or) total AKT, and susceptibility to hypoxia-induced apoptosis. Our data suggests a model in which regulated loss of active AKT at a precise time point in hypoxia may be associated with apoptosis in susceptible cells.

scholarly journals Suppression of p53 function in normal human mammary epithelial cells increases sensitivity to extracellular matrix–induced apoptosis

2001 ◽  
Vol 155 (3) ◽  
pp. 471-486 ◽  
Author(s):  
Victoria L. Seewaldt ◽  
Krzysztof Mrózek ◽  
Randy Sigle ◽  
Eric C. Dietze ◽  
Kevin Heine ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Epithelial Cells ◽  
Mammary Epithelial Cells ◽  
Growth Arrest ◽  
Mammary Epithelial ◽  
Early Passage ◽  
Human Mammary Epithelial Cells ◽  
Human Mammary Epithelial ◽  
Normal Human ◽  
Induced Apoptosis

Little is known about the fate of normal human mammary epithelial cells (HMECs) that lose p53 function in the context of extracellular matrix (ECM)–derived growth and polarity signals. Retrovirally mediated expression of human papillomavirus type 16 (HPV-16) E6 and antisense oligodeoxynucleotides (ODNs) were used to suppress p53 function in HMECs as a model of early breast cancer. p53+ HMEC vector controls grew exponentially in reconstituted ECM (rECM) until day 6 and then underwent growth arrest on day 7. Ultrastructural examination of day 7 vector controls revealed acinus-like structures characteristic of normal mammary epithelium. In contrast, early passage p53− HMEC cells proliferated in rECM until day 6 but then underwent apoptosis on day 7. p53− HMEC-E6 passaged in non-rECM culture rapidly (8–10 passages), lost sensitivity to both rECM-induced growth arrest and polarity, and also developed resistance to rECM-induced apoptosis. Resistance was associated with altered expression of α3-integrin. Treatment of early passage p53− HMEC-E6 cells with either α3- or β1-integrin function-blocking antibodies inhibited rECM-mediated growth arrest and induction of apoptosis. Our results indicate that suppression of p53 expression in HMECs by HPV-16 E6 and ODNs may sensitize cells to rECM-induced apoptosis and suggest a role for the α3/β1-heterodimer in mediating apoptosis in HMECs grown in contact with rECM.

Sign in / Sign up

Export Citation Format

Share Document