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Omega-3 Polyunsaturated Fatty Acids Trigger Cell Cycle Arrest and Induce Apoptosis in Human Neuroblastoma LA-N-1 Cells.

So WW, Liu WN, Leung KN - Nutrients (2015)

Bottom Line: Omega-3 (n-3) fatty acids are dietary long-chain fatty acids with an array of health benefits.Up-regulation of Bax, activated caspase-3 and caspase-9 proteins, and down-regulation of Bcl-XL protein, might account for the occurrence of apoptotic events.Collectively, our results suggest that the growth-inhibitory effect of DHA and EPA on LA-N-1 cells might be mediated, at least in part, via triggering of cell cycle arrest and apoptosis.

View Article: PubMed Central - PubMed

Affiliation: Biochemistry Programme, School of Life Sciences, The Chinese University of Hong Kong, Shatin, Hong Kong, China. timothyso30@hotmail.com.

ABSTRACT
Omega-3 (n-3) fatty acids are dietary long-chain fatty acids with an array of health benefits. Previous research has demonstrated the growth-inhibitory effect of n-3 fatty acids on different cancer cell lines in vitro, yet their anti-tumor effects and underlying action mechanisms on human neuroblastoma LA-N-1 cells have not yet been reported. In this study, we showed that docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) exhibited time- and concentration-dependent anti-proliferative effect on the human neuroblastoma LA-N-1 cells, but had minimal cytotoxicity on the normal or non-tumorigenic cells, as measured by MTT reduction assay. Mechanistic studies indicated that DHA and EPA triggered G0/G1 cell cycle arrest in LA-N-1 cells, as detected by flow cytometry, which was accompanied by a decrease in the expression of CDK2 and cyclin E proteins. Moreover, DHA and EPA could also induce apoptosis in LA-N-1 cells as revealed by an increase in DNA fragmentation, phosphatidylserine externalization and mitochondrial membrane depolarization. Up-regulation of Bax, activated caspase-3 and caspase-9 proteins, and down-regulation of Bcl-XL protein, might account for the occurrence of apoptotic events. Collectively, our results suggest that the growth-inhibitory effect of DHA and EPA on LA-N-1 cells might be mediated, at least in part, via triggering of cell cycle arrest and apoptosis. Therefore, DHA and EPA are potential anti-cancer agents which might be used for the adjuvant therapy or combination therapy with the conventional anti-cancer drugs for the treatment of some forms of human neuroblastoma with minimal toxicity.

No MeSH data available.


Related in: MedlinePlus

DHA and EPA trigger phosphatidylserine externalization in LA-N-1 cells. (A–D) LA-N-1 cells were incubated with ethanol control (A), 30 or 50 µM DHA (B, C) for 48 hours. (E–H) LA-N-1 cells were incubated with ethanol control (E), 30 or 50 µM or EPA (F, G) for 48 hours. After incubation, the cells were stained by Annexin V-GFP fusion protein and PI, and the fluorescence intensity was measured by flow cytometry. The results are quantified and expressed as mean values ± SD (D, H). ** p < 0.01.
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nutrients-07-05319-f004: DHA and EPA trigger phosphatidylserine externalization in LA-N-1 cells. (A–D) LA-N-1 cells were incubated with ethanol control (A), 30 or 50 µM DHA (B, C) for 48 hours. (E–H) LA-N-1 cells were incubated with ethanol control (E), 30 or 50 µM or EPA (F, G) for 48 hours. After incubation, the cells were stained by Annexin V-GFP fusion protein and PI, and the fluorescence intensity was measured by flow cytometry. The results are quantified and expressed as mean values ± SD (D, H). ** p < 0.01.

Mentions: Apart from DNA fragmentation, PS externalization is another hallmark feature of apoptosis [28]. In the present study, Annexin V-GFP fusion protein and PI co-staining method was employed to monitor the PS externalization. Flow cytometric analysis showed that the percentage of cells with PS externalization increased when the cells were treated with DHA (Figure 4A–D) or EPA (Figure 4E–H). In addition, previous studies have suggested that cell cycle arrest might be a result of mitochondrial failure [29], hence the mitochondrial membrane potential of the treated cells was examined by JC-1 dye staining method. It was found that the mitochondrial membrane potential in LA-N-1 cells was reduced after treatment with DHA (Figure 5A–D) and EPA (Figure 5E–H) in a concentration-dependent manner.


Omega-3 Polyunsaturated Fatty Acids Trigger Cell Cycle Arrest and Induce Apoptosis in Human Neuroblastoma LA-N-1 Cells.

So WW, Liu WN, Leung KN - Nutrients (2015)

DHA and EPA trigger phosphatidylserine externalization in LA-N-1 cells. (A–D) LA-N-1 cells were incubated with ethanol control (A), 30 or 50 µM DHA (B, C) for 48 hours. (E–H) LA-N-1 cells were incubated with ethanol control (E), 30 or 50 µM or EPA (F, G) for 48 hours. After incubation, the cells were stained by Annexin V-GFP fusion protein and PI, and the fluorescence intensity was measured by flow cytometry. The results are quantified and expressed as mean values ± SD (D, H). ** p < 0.01.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4555158&req=5

nutrients-07-05319-f004: DHA and EPA trigger phosphatidylserine externalization in LA-N-1 cells. (A–D) LA-N-1 cells were incubated with ethanol control (A), 30 or 50 µM DHA (B, C) for 48 hours. (E–H) LA-N-1 cells were incubated with ethanol control (E), 30 or 50 µM or EPA (F, G) for 48 hours. After incubation, the cells were stained by Annexin V-GFP fusion protein and PI, and the fluorescence intensity was measured by flow cytometry. The results are quantified and expressed as mean values ± SD (D, H). ** p < 0.01.
Mentions: Apart from DNA fragmentation, PS externalization is another hallmark feature of apoptosis [28]. In the present study, Annexin V-GFP fusion protein and PI co-staining method was employed to monitor the PS externalization. Flow cytometric analysis showed that the percentage of cells with PS externalization increased when the cells were treated with DHA (Figure 4A–D) or EPA (Figure 4E–H). In addition, previous studies have suggested that cell cycle arrest might be a result of mitochondrial failure [29], hence the mitochondrial membrane potential of the treated cells was examined by JC-1 dye staining method. It was found that the mitochondrial membrane potential in LA-N-1 cells was reduced after treatment with DHA (Figure 5A–D) and EPA (Figure 5E–H) in a concentration-dependent manner.

Bottom Line: Omega-3 (n-3) fatty acids are dietary long-chain fatty acids with an array of health benefits.Up-regulation of Bax, activated caspase-3 and caspase-9 proteins, and down-regulation of Bcl-XL protein, might account for the occurrence of apoptotic events.Collectively, our results suggest that the growth-inhibitory effect of DHA and EPA on LA-N-1 cells might be mediated, at least in part, via triggering of cell cycle arrest and apoptosis.

View Article: PubMed Central - PubMed

Affiliation: Biochemistry Programme, School of Life Sciences, The Chinese University of Hong Kong, Shatin, Hong Kong, China. timothyso30@hotmail.com.

ABSTRACT
Omega-3 (n-3) fatty acids are dietary long-chain fatty acids with an array of health benefits. Previous research has demonstrated the growth-inhibitory effect of n-3 fatty acids on different cancer cell lines in vitro, yet their anti-tumor effects and underlying action mechanisms on human neuroblastoma LA-N-1 cells have not yet been reported. In this study, we showed that docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) exhibited time- and concentration-dependent anti-proliferative effect on the human neuroblastoma LA-N-1 cells, but had minimal cytotoxicity on the normal or non-tumorigenic cells, as measured by MTT reduction assay. Mechanistic studies indicated that DHA and EPA triggered G0/G1 cell cycle arrest in LA-N-1 cells, as detected by flow cytometry, which was accompanied by a decrease in the expression of CDK2 and cyclin E proteins. Moreover, DHA and EPA could also induce apoptosis in LA-N-1 cells as revealed by an increase in DNA fragmentation, phosphatidylserine externalization and mitochondrial membrane depolarization. Up-regulation of Bax, activated caspase-3 and caspase-9 proteins, and down-regulation of Bcl-XL protein, might account for the occurrence of apoptotic events. Collectively, our results suggest that the growth-inhibitory effect of DHA and EPA on LA-N-1 cells might be mediated, at least in part, via triggering of cell cycle arrest and apoptosis. Therefore, DHA and EPA are potential anti-cancer agents which might be used for the adjuvant therapy or combination therapy with the conventional anti-cancer drugs for the treatment of some forms of human neuroblastoma with minimal toxicity.

No MeSH data available.


Related in: MedlinePlus