Chemotherapy Prevents OS Invasion by EGR1 Figure 3. Anti-tumor agent treatment increased the expression of EGR1. Following 24 h drug treatments, total RNA extracted from osteosarcoma cell lines were analyzed by real-time PCR. Treatment with cisplatin, methotrexate, etoposide or doxorubicin increased EGR1 expression in 143B and Saos-2 cells. The comparative Ct (DDCt) method was used to determine fold change in expression using GAPDH or ACTB. Experiments were performed in triplicate with similar results [error bars represent mean (SD)]. doi:10.1371/journal.pone.0016234.g003 PLoS ONE | www.plosone.org 5 January 2011 | Volume 6 | Issue 1 | e16234