Cyclophilin B expression is associated with in vitro radioresistance and clinical outcome after radiotherapy

Paul D. Williams, Charles R. Owens, Jaroslaw Dziegielewski, Christopher A. Moskaluk, Paul W. Read, James M. Larner, Michael D. Story, William A. Brock, Sally A. Amundson, Jae K. Lee, Dan Theodorescu*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

19 Scopus citations


The tools for predicting clinical outcome after radiotherapy are not yet optimal. To improve on this,weapplied theCOXENinformatics approach to in vitro radiation sensitivity data of transcriptionally profiled human cells and gene expression data fromuntreated head and neck squamous cell carcinoma (HNSCC) and bladder tumors to generate a multigene predictive model that is independent of histologic findings and reports on tumor radiosensitivity. The predictive ability of this 41-gene model was evaluated in patients with HNSCC and was found to stratify clinical outcome after radiotherapy. In contrast, this model was not useful in stratifying similar patients not treated with radiation. This led us to hypothesize that expression of some of the 41 genes contributes to tumor radioresistance and clinical recurrence. Hence, we evaluated the expression the 41 genes as a function of in vitro radioresistance in the NCI-60 cancer cell line panel and found cyclophilin B (PPIB), a peptidylprolyl isomerase and target of cyclosporine A (CsA), had the strongest direct correlation. Functional inhibition of PPIB by small interfering RNA depletion or CsA treatment leads to radiosensitization in cancer cells and reduced cellular DNA repair. Immunohistochemical evaluation of PPIB expression in patients with HNSCC was found to be associated with outcome after radiotherapy. This work demonstrates that a novel 41-gene expression model of radiation sensitivity developed in bladder cancer cell lines and human skin fibroblasts predicts clinical outcome after radiotherapy in head and neck cancer patients and identifies PPIB as a potential target for clinical radiosensitization.

Original languageEnglish
Pages (from-to)1122-1131
Number of pages10
Issue number12
StatePublished - Dec 2011
Externally publishedYes


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