High homocysteine promotes telomere dysfunction and chromosomal instability in human neuroblastoma SH-SY5Y cells

• Published in: Mutation research. Genetic toxicology and environmental mutagenesis Vol. 854-855; p. 503197
• Main Authors: Hu, Xialian, Guo, Xihan, Ni, Juan, Wang, Han, Cao, Neng, Liang, Ziqing, Wang, Xu
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-06-2020
• Subjects: Cytokinesis-block micronucleus cytome (CBMN-Cyt) assay; hTERT; Micronucleus; Nuclear bud; Nucleoplasmic bridge; Cytokinesis-block micronucleus cytome (CBMN-Cyt) assay; Nuclear bud; hTERT; Nucleoplasmic bridge; Micronucleus
• ISSN: 1383-5718; 1879-3592
• DOI: 10.1016/j.mrgentox.2020.503197

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•SH-SY5Y cells were treated with pathophysiological concentrations of Hcy (15–120 μM) for 14 and 28 days.•Hcy induced elongation of TL and fluctuating changes in expression of hTERT.•Abnormal elongation of TL was associated with increased frequency of micronuclei, nucleoplasmic bridges and nuclear buds.•Hcy increased cytostasis and frequency of apoptotic and necrotic cell death.
Telomeres, specialized structures at the ends of linear chromosomes, protect chromosome ends from degradation, recombination, and mis-repair. Critically short telomere length (TL) may result in chromosome instability (CIN), causing tumor promotion and, at higher levels, cell death and tumor suppression. Homocysteine (Hcy) is a sulfur-containing amino acid involved in one-carbon metabolism. Elevated plasma Hcy is a cancer risk factor. Human SH-SY5Y neuroblastoma cells were treated with pathophysiological concentrations of Hcy (15–120 μM) for 14 and 28 days. The cytokinesis-block micronucleus cytome assay was used to determine cytostasis (nuclear division index, NDI), cell death (apoptosis and necrosis), and CIN (micronuclei, nucleoplasmic bridges, and nuclear buds in binucleated cells). Quantitative PCR was used to measure TL and the expression of hTERT, the gene encoding the catalytic subunit of telomerase for TL elongation. The results showed that Hcy induced elongation of TL and fluctuating changes in expression of hTERT. TL elongation was associated with increased CIN. Hcy decreased the NDI and increased cell death. This study shows that there is cross-talk between Hcy and TL in tumor cells and supports the concept that high Hcy inhibits cell division and promotes the death of tumor cells by abnormal elongation of TL and elevation of CIN.