title: Enhanced radiation response in radioresistant MCF-7 cells by targeting peroxiredoxin II.
abstract: In our previous study, we identified that a protein target, peroxiredoxin II (PrxII), is overexpressed in radioresistant MCF+FIR3 breast-cancer cells and found that its expression and function is associated with breast-cancer radiation sensitivity or resistance. Small interference RNA (siRNA) targeting PrxII gene expression was able to sensitize MCF+FIR3 radioresistant breast-cancer cells to ionizing radiation. The major focus of this work was to investigate how the radiation response of MCF+FIR3 radioresistant cells was affected by the siRNA that inhibits PrxII gene expression. Our results, presented here, show that silencing PrxII gene expression increased cellular toxicity by altering cellular thiol status, inhibiting Ca(2+) efflux from the cells, and perturbing the intracellular Ca(2+) homeostasis. By combining radiotherapy and siRNA technology, we hope to develop new therapeutic strategies that may have potential to enhance the efficacy of chemotherapeutic agents due to this technology's property of targeting to specific cancer-related genes.
authors.affiliation: Department of Chemistry and Biochemistry, California State University at Dominguez Hills, Carson, CA.
authors.forename: Anthony Joseph Gomez
authors.initials: AJ
authors.lastname: Diaz
authors.affiliation: Center of Excellence in Environmental Toxicology, Department of Pharmacology, University of Pennsylvania, Philadelphia, PA.
authors.forename: Daniel
authors.initials: D
authors.lastname: Tamae
authors.affiliation: Department of Clinical and Molecular Pharmacology, Beckman Research Institute of City of Hope National Medical Center, Duarte, CA.
authors.forename: Yun
authors.initials: Y
authors.lastname: Yen
authors.affiliation: Department of Radiation Oncology, University of California Davis, Sacramento, CA, USA.
authors.forename: Jianjian
authors.initials: J
authors.lastname: Li
authors.affiliation: Department of Chemistry and Biochemistry, California State University at Dominguez Hills, Carson, CA.
authors.forename: Tieli
authors.initials: T
authors.lastname: Wang
keywords: Ca2+; MCF+FIR3; PrxII; radiation resistance; siRNA