R. J. Ryan1, P. Ramamoorthy1, S. J. Weir2, S. Anant1, P. DiPasco1 1University Of Kansas,General Surgery,Kansas City, KS, USA 2University Of Kansas,Pharmacology, Toxicology And Therapeutics,Kansas City, KS, USA
Introduction:
Esophageal carcinoma is a devastating diagnosis with an overwhelmingly poor prognosis. More than 30% of patients have metastatic disease on presentation, and 5 year survival in these patients is 3.5%. Chemo-radiotherapy is the primary treatment modality of advanced disease, but current chemotherapeutic agents only prolong life for months to a few years. Drug repositioning is an important pharmacologic strategy that involves investigation and implementation of known drugs for treatment of new diseases. This method significantly reduces the costs required for establishing the safety of a drug and is associated with higher rates of drug approval. Ciclopirox olamine (CPX) is an antifungal agent that has been on the market since the 1970s. The mechanism of action is believed to include disrupting DNA repair and cell division signals. The compound is also believed to affect the membrane transfer system by interrupting the Na+ K+ ATPase. We have recently been looking at the anti-tumor properties of CPX. In preclinical studies, CPX has been shown to inhibit growth of cell lines for human breast carcinoma, bladder cancer and colon adenocarcinoma. Here, we present our preliminary results of the effects of CPX on esophageal carcinoma cells.
Methods:
We maintained two esophageal cancer cell lines, TE-7 and TE-10 in standard culture flasks with RPMI media. Cell lines were exposed to CPX and the effects are reported. Proliferation assays were performed as follows. Cultured cells from each cell line were exposed to CPX for 24, 48 and 72 h, after which cells were lysed and hexosaminidase assay was performed. Colony formation assays were performed as follows. Cultured cells were diluted to 500 cells/mL, plated, and exposed to increasing concentrations of CPX for 48 h. After exposure, cells were incubated in standard media for 10 days. Cells were then fixed and stained with crystal violet dye. Cell cycle analysis was performed on cells from both cells lines after exposure to CPX for 48 h. Cells were permeabilised and treated with propidium iodide before running through flow cytometry.
Results:
CPX causes growth inhibition of TE-7 and TE-10 esophageal cancer cell lines. Results of proliferation assay revealed growth inhibition of esophageal cancer cells from TE-7 and TE-10 cell lines in a dose and time-dependent manner. Cell cycle assay also showed growth inhibition of both cell lines in a concentration dependent manner. On cell cycle analysis, cells exposed to CPX revealed cell-cycle arrest in G2/M phase
Conclusion:
Ciclopirox olamine (CPX) is an FDA-approved antifungal agent recently shown to have anti-tumor properties. To date, there is no published data on CPX as a potential target of esophageal carcinoma. We have demonstrated growth inhibition of two esophageal cancer cell lines when exposed to CPX. These data pave the way for further research into the mechanisms of growth inhibition and potential use of this agent in the treatment of esophageal carcinoma.