Dose-Dependent Effects of MNNG on Cell Viability and Autophagy in SH-SY5Y Neuroblastoma Cells

Bal Albayrak M. G., Yanar S., Korak T., Kasap M.

The 22nd Turkish Neuroscience Congress, İstanbul, Türkiye, 3 - 06 Eylül 2024, ss.42-43

  • Yayın Türü: Bildiri / Özet Bildiri
  • Basıldığı Şehir: İstanbul
  • Basıldığı Ülke: Türkiye
  • Sayfa Sayıları: ss.42-43
  • Kocaeli Üniversitesi Adresli: Evet

Özet

Objective: Methyl-N’-nitro-N-nitrosoguanidine (MNNG) is a DNA-damaging agent that induces cellular

stress responses, including autophagy and cell death mechanisms. SH-SY5Y cells, derived from human

neuroblastoma, are used to study neurodegenerative diseases. This study explores the dose-dependent

effects of MNNG on cell viability and autophagy in SH-SY5Y cells.

Material and Methods: SH-SY5Y cells were treated with 25, 50, 75, 100, and 125 μM of MNNG for 1

and 4 hours, and cell viability was assessed using the WST-1 assay. Beclin-1 expression levels were

quantified by Western blot analysis, using β-actin as the reference protein. Autophagic vesicle formation

was assessed using the Autophagy Detection Kit (ab139484, Abcam) with cell imaging. Statistical

analysis and graphic representations were performed using GraphPad Prism 9.1.0 by one-way ANOVA. P

values <0.05 were considered significant.

Results: WST-1 assay indicated statistically significant reductions (p<0.05) in cell viability at 50 μM and

100 μM MNNG. Consequently, these doses were selected for further investigation. Western blot analysis

revealed statistically significant increase in Beclin-1 levels at 50 μM MNNG (p<0.001) and decrease at

100 μM (p<0.05). Autophagy assays and cell imaging showed a marked increase in autophagic vesicles at

50 μM MNNG, and a decrease at 100 μM, correlating with Western blot results.

Conclusion: Our findings demonstrate that MNNG induces a dose-dependent response in SH-SY5Y

cells. At 50 μM, Beclin-1 is upregulated, activating autophagy as a survival mechanism. At 100 μM,

decreased Beclin-1 suggests autophagy suppression, shifting towards cell death mechanisms like

parthanatos, common in neurodegenerative diseases, or apoptosis due to excessive DNA damage. These

observations suggest that lower doses of MNNG induce a more balanced response between survival and

death mechanisms, while higher doses lead to cell death. This study highlights the complex relationship

between DNA damage, autophagy, and cell viability, providing valuable insights into cellular responses to

genotoxic stress in neuroblastoma cells.

Keywords: autophagy, Beclin-1, cell viability, MNNG, SH-SY5Y