Research Information System
Journal of Natural Medicines, vol.80, no.1, pp.64-75, 2026 (SCI-Expanded, Scopus)
Naturally occurring compounds like Theobromine, found in tea, coffee, and cocoa, may have anticancer effects. This study explores how Theobromine induces cell death and apoptosis in bladder cancer cells and its impact on NRF2-related gene activity. Two human bladder cancer cell lines—RT112 (non-invasive) and HTB9 (invasive)—were employed. Cell viability was measured using the WST-1 assay, whereas apoptosis and caspase 3/7 activation were determined through flow cytometry. qPCR was performed to measure the expression of NRF2, KEAP1, and P62 genes. Theobromine exhibited a dose-dependent reduction in cell viability in both RT112 and HTB9 bladder cancer cells, while also significantly enhancing apoptosis and caspase 3/7 activity (p<0.0001). Flow cytometry analysis indicated G1-phase arrest in RT112 cells and S-phase accumulation in HTB9 cells following Theobromine treatment, while Cisplatin induced S-phase arrest in both cell lines. Theobromine suppressed NRF2 and P62 while increasing KEAP1 levels in HTB9 cells, suggesting NRF2 pathway inhibition. For RT112 cells, Theobromine upregulated NRF2 and P62 without altering KEAP1 expression, highlighting cell type-specific modulation of the NRF2 signaling pathway. This study shows that Theobromine differentially regulates the Nrf2-Keap1-p62 pathway in bladder cancer cells, inhibiting NRF2 and P62 expression in a cell-specific manner. These findings suggest its potential as a natural anticancer compound, warranting further in vivo studies to assess its therapeutic potential.