Assessing the cytotoxicity of investigational agent for cancer therapy against non-malignant cells

Background: The treatment of cancer requires chemotherapy (ChT). Most of ChT agents exhibit unwanted side-effect and cause damage to healthy cells. Side effects from commonly used ChT agents are leaving pediatric cancer survivors with lasting damage to organ systems, specifically the heart. Studies conducted by our group demonstrated the anti-cancer activity of clotam (tolfenamic acid-TA) and copper-clotam (Cu-TA). Cu-TA is showing higher cytotoxicity against cancer cells even at much lower dose than TA in pancreatic cancer cells. Our long term objective is to test these agents 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 CellTiter-Glo (Promega) kit at 48 hours post-treatment following manufacturer's instructions. Results & Conclusion: We found that TA or Cu-TA are not inducing toxicity in H9c2 cells at tested doses. TA kept more cells alive in conjunction with Doxorubicin than did the control. Our studies also show that H9c2 cells are not toxic to IC50 values of TA or Cu-TA determined with cancer cells. These results provide evidence that the tested investigational gents are not inducing toxicity in cardiomyocytes at tested doses and supports use of these agents in combination therapy with ChT.