Omega-3 Polyunsaturated Fatty Acids Trigger Cell Cycle Arrest and Induce Apoptosis in Human Neuroblastoma LA-N-1
Wai Wing So1, Wai Nam Liu2, Kwok Nam Leung3
1Biochemistry 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.
Insights
Omega-3 fatty acids, specifically docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), inhibit neuroblastoma cell growth by inducing cell cycle arrest and apoptosis. These fatty acids show potential as anti-cancer agents with minimal toxicity to normal cells.
Area of Science:
- Nutrition Science
- Cancer Biology
- Molecular Oncology
Background:
- Omega-3 (n-3) fatty acids are recognized for their health benefits.
- Previous studies indicate n-3 fatty acids inhibit various cancer cell lines.
- The specific anti-tumor effects of n-3 fatty acids on human neuroblastoma LA-N-1 cells remain uninvestigated.
Purpose of the Study:
- To investigate the anti-proliferative effects of docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) on human neuroblastoma LA-N-1 cells.
- To elucidate the underlying mechanisms of action, including cell cycle regulation and apoptosis induction.
- To assess the selective toxicity of DHA and EPA towards neuroblastoma cells compared to normal cells.
Main Methods:
- MTT reduction assay to measure cell proliferation and cytotoxicity.
- Flow cytometry to detect cell cycle arrest.
- Western blotting to analyze protein expression (e.g., CDK2, cyclin E, Bax, Bcl-XL, caspases).
- Apoptosis assays including DNA fragmentation, phosphatidylserine externalization, and mitochondrial membrane potential assessment.
Main Results:
- DHA and EPA demonstrated time- and concentration-dependent anti-proliferative effects on LA-N-1 cells.
- Minimal cytotoxicity was observed on normal or non-tumorigenic cells.
- Cell cycle arrest at the G0/G1 phase was induced, associated with decreased CDK2 and cyclin E expression.
- Apoptosis was triggered, evidenced by increased DNA fragmentation, phosphatidylserine externalization, and mitochondrial depolarization.
- Modulation of apoptosis-related proteins (up-regulation of Bax, activated caspases; down-regulation of Bcl-XL) was observed.
Conclusions:
- DHA and EPA inhibit neuroblastoma LA-N-1 cell growth primarily through cell cycle arrest and apoptosis induction.
- These omega-3 fatty acids exhibit potential as anti-cancer agents for neuroblastoma treatment.
- DHA and EPA may be suitable for adjuvant or combination therapy with conventional anti-cancer drugs due to their selective toxicity.
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