Determining the cytotoxicity of Clotam and Copper-Clotam against Cardiomyocytes

Background: Chemotherapy (ChT) is required in the treatment of many cancers. Most ChT agents exhibit unwanted side-effects by causing damage to healthy cells. Side effects from many common ChT agents are leaving pediatric cancer survivors with lasting organ system damage, specifically damage to the heart. Past studies conducted by our group demonstrated the anti-cancer activity of clotam (tolfenamic acid-TA) and copper-clotam (CuTA). Our laboratory demonstrated the anti-cancer activity of CuTA against several cancer cell lines. CuTa is showing higher cytotoxicity against cancer cells even at much lower dose than TA. Our long term objective is to test CuTA to sensitize cancer cells to ChT. Methods: Cardiomyocytes H9c2 (cell line derived from rat heart tissue) originally obtained from the American Type Culture Collection (Manassas, VA) were cultured as per the supplier's instructions. H9c2 cells were treated with TA or Cu-TA or Doxorubicin and combinations (for example, TA and Doxorubicin) and cell viability assay was measured using CellTiterGlo (Promega) kit at 48 hours post-treatment following manufacturer's instructions. Results & Conclusion: We found that TA or CuTA were not cytotoxic in H9c2 cells at tested doses. TA kept more cells alive in conjunction with Doxorubicin than did the control. Our results also demonstrate that the IC50 values of TA and CuTA, determined with cancer cell lines, are not toxic to H9c2 cells. These results provide evidence that CuTA does not induce toxicity in cardiomyocytes and supports further testing for translational application in combination therapy with ChT.