[57] Gene Expression Profile of Chemotherapy Effect on Human Ewing Sarcoma Cell Lines

MM Bui, CY Fan, SA Schichman, YO Zhang, CI Cubitt, J Menth, PJ Zhang, D Sullivan. Moffitt Cancer Center, Tampa, FL; Central Arkansas Veterans Healthcre System, Little Rock, AR; University of Pennsylvania Medical Center, Philadelphia, PA

Background: Multimodality therapy includes surgery, radiation and chemotherapy/neoadjuvant chemotherapy is the cornerstone of current treatment of Ewing Sarcoma (ES). Chemotherapy regimens usually include drugs such as doxorubicin (antitumor antibiotic), etoposide (topoisomerse II inhibitor) and 4 hydroperoxycyclophosphamide (4-HC), ifosfamide or cyclophosphamide (alkylating agent). Understanding the molecular mechanism of drug effect is important in developing best therapeutic regimens to minimize drug resistance. Herein, we investigated the gene expression profile of ES cell lines subjected to chemotherapies with single and multiple agents.
Design: Three human ES cell lines (A673, SKES and RDES) each were incubated without any agent, with single agent, or with combination of doxorubicin (dox), etoposide (etop) and 4-HC at the concentration killing 30% of the cells in 24 hrs. The extracted RNA was then subjected to Sentrix BeadChip Array HumanHT-12_v3_BeadChip (Illumina, San Diego, CA) for gene expression analysis with appropriate quality and reproducibility controls.
Results: RNA of all experimental groups except A670 with combination treatment were sufficient for profiling. Signature genes for ES (such as EWS, FLI1, ETV1 and ZSG) were present. Out of 38,000 genes evaluated, 13, 913 genes probes were expressed in most of the samples (8 or more). Fifty-eight probes showed significant change in expression after treatment with each drug (t-test, p<0.05). Among them RPS20, RPL8, and RPS25 were up regulated up to 2 folds; while CPT1B, C11OKF47 and KIF27 were down regulated up to 5 folds. Combination drug therapy revealed up-regulation up to 4 folds and down-regulation up to 18 folds.
Conclusions: Significant differential gene expression (especially 58 genes) was seen in ES cell lines subjected to single and combo drug therapy compared to controls. Enhanced effect on specific gene expression by combination therapy suggests an addictive/synergistic antitumor effect due to regulation of similar molecular signatures. These finding may aid in design of future studies of clinical samples and larger series for predicting and monitoring chemotherapy response and for identificaition of potential molecular targets.
Category: Bone & Soft Tissue

Tuesday, March 23, 2010 2:15 PM

Platform Session: Section E, Tuesday Afternoon


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