Investigating the Circadian-Dependent Effects of REV-ERB Agonists on Melanoma Cell Viability and Apoptosis
By Avni Gupta | Valley Christian High School, San Jose, California, United States
I. Abstract
Circadian rhythms regulate essential biological processes by synchronizing cellular functions with the 24-hour light-dark cycle. Using clock-controlled genes, such as BMAL1 and REV-ERB, circadian rhythms influence apoptosis and DNA repair. Disruptions in circadian regulation, commonly observed in cancer, lead to uncontrolled proliferation and altered DNA repair activity. The REV-ERB agonist SR9009 is known to impair autophagy and promote apoptosis in cancer cells, making it a potential candidate for use in cancer treatment. Since the upregulation of DNA repair fluctuates with the light-dark circadian cycle, several assays of B16-F10 melanoma cells were treated with SR9009 at varying time points to probe the relationship between effectivity of the agent and timing of administration. The cells were synchronized using serum deprivation and serum shock, then treated with 10 µM SR9009 at five circadian time points: 0, 2, 4, 6, and 8 hours. A vehicle control and untreated control group were included. After 24 hours, flow cytometry was used with propidium iodide staining to assess cell viability. There were significant reductions in viability at 0 hr (89.75% to 70.65%, P = 0.0271, R² = 0.9466) and 8 hr (to 55.05%, P = 0.0204, R² = 0.9597), which supported a time-dependent response to SR9009. No statistically significant changes were observed at 2 hr, 4 hr, or 6 hr. Although repeated measures ANOVA showed no overall treatment effect, this may be attributed to limited statistical power (n=2) and high variability. The data indicates that SR9009 reduces viability during two distinct circadian phases: one at the onset of the subjective day and another as repair activity begins to decline. However, since only two replicates were completed due to lab hour constraints, further tests with more samples are needed to further solidify the findings.
II. Research Poster
The research poster published, “Investigating the Circadian-Dependent Effects of REV-ERB Agonists on Melanoma Cell Viability and Apoptosis,” was received on July 13, 2025, and was reviewed and accepted on July 21, 2025. To contact editors and reviewers please click here.
