Byline: Bowen. Yang, Xiaoke. Huang, Weiguo. Li, Samdeep. Mouli, Robert. Lewandowski, Andrew. Larson
Objective: The objective of this study is to explore the radiosensitization effects of duramycin against the liver cancer hepatoma cells and relationship to reactive oxygen species (ROS) generation. Materials and Methods: MCA-RH 7777 cells were treated with various combinations of duramycin concentrations and radiation doses. After the treatment, cell viabilities were determined by a cell proliferation assay; intracellular ROS levels were detected with the flow cytometric method. Results: MCA-RH 7777 cell viability was found significantly reduced after combining duramycin and radiation exposure (comparing to that of either treatment alone). Increased intracellular ROS levels were observed in cells treated with combinations of duramycin and radiation. Conclusion: Duramycin increased the intracellular ROS generation and also increased the radiosensitivity of MCA-RH 7777 cells.
One of the major hurdles in treating cancer is that tumor cells develop resistance to radiotherapy. Improving radiosensitivity of cancer cells is an urgent clinical need with a goal of achieving curative effects while protecting the surrounding normal tissues. Mounting evidence has indicated that radioresistance of cancer cells can be reduced by anticancer agents that induce the production of intracellular reactive oxygen species (ROS).
As a potential effective antitumor agent, duramycin was reported to specifically bind to phosphoethanolamine (PE) in the target cell membrane to induce calcium ion (Ca2+) release from cancer cells., Calcium signaling pathways can interact with cellular signaling systems such as ROS systems that play an important role in fine-tuning cellular signaling networks. Thus, duramycin may sensitize cell to radiotherapy through the changes in cellular ROS level.
In the present study, we treated a hepatoma cell line MCA-RH 7777 with various concentrations of duramycin and different radiation levels to observe the cytotoxicity and radiosensitizing effects of duramycin.
Materials and Methods
Cell culture and agents
Hepatoma cell line, MCA-RH 7777, was obtained from American Type Culture Collection (ATCC, Manassas, VA, USA). The cells were cultured in Dulbecco's Modified Eagle's Medium (Sigma-Aldrich, St. Louis, MO, USA) supplemented with 20% fetal bovine serum (Sigma-Aldrich) at 37°C in a humidified atmosphere containing 5% CO[sub]2. Duramycin (Sigma-Aldrich) was dissolved in hydrogen chloride to a stock concentration of 10 mM and stored at 4°C.
MCA RH-7777 cells (4 × 105) were seeded into four 96-well plates. After incubation for 1 day, cells on each plate were divided into four groups and treated with duramycin of four different concentrations (0, 1, 2, and 4 µM) for 4 h, respectively; then, each plate was irradiated with a-(60 Co) radiation with one of four different dose levels (0, 2,...