Comparative Cytotoxic and Anti-Migratory Effects of Cisplatin and Theobromine in Human Bladder Cancer Cells

Background: Bladder cancer continues to pose a major global health challenge, as therapeutic options are often con-strained by treatment-related toxicity and the emergence of resistance to chemotherapy. We investigated the cytotoxic and anti-migratory effects of Theobromine, a natural alkaloid, in HT-1376 bladder cancer cells and compared its activity with Cisplatin, a standard chemotherapeutic agent.Methods: Cellular metabolic activity was quantified via the WST-1 colorimetric assay, while migratory capacity was examined using wound healing assay.Results: Treatment with Theobromine induced a time- and dose-responsive decrease in HT-1376 cell viability, with IC₅₀ values of 134.3 µM after 24 h, while Cisplatin exhibited stronger cytotoxicity with an IC₅₀ value of 35.97 µM. Both agents significantly inhibited cell migration, with the combination of Theobromine and Cisplatin showing the most pronounced anti-migratory effect. The wound healing assay revealed that the combination treatment significantly reduced wound closure compared to either compound alone (p 0.0001), while Theobromine alone resulted in moderate inhibition (p = 0.0001). Importantly, no significant cytotoxicity was observed in NIH/3T3 fibroblast cells at concentrations up to 200 µM for Theobromine and 50 µM for Cisplatin, indicating differential sensitivity between bladder cancer cells and normal fibroblast cells.Conclusion: These findings suggest that Theobromine may act as a potential adjunct to Cisplatin-based therapy in blad-der cancer cells. Further experimental studies are required to elucidate the underlying molecular mechanisms responsible for the enhanced inhibitory effect and to evaluate the efficacy of this combined treatment in animal models.