Cimica et al. BMC Cancer 2010, 10:634 http://www.biomedcentral.com/1471-2407/10/634 Page 9 of 13 Figure 6 Effect of p53 knock-down on flavopiridol- and 4OH-Tam-induced cell cycle arrest and apoptosis: A. Immunoblot analysis to indicate siRNA mediated knock-down of p53 in MON cells treated with flavopiridol and 4OH-Tam for two days B. Percentage of diploid MON cells at various stages of cell cycle after treatment with control (Cy3) siRNA followed by treatment with flavopiridol and 4OH-Tam for two days. Note the lack of G2 arrest upon drug treatment of p53-knock-down cells. C. Percentage of diploid MON cells at various stages of cell cycle after p53 knockdown (using siRNA to p53) and treatment with flavopiridol and 4OH-Tam for two days. D. Percentage of MON cells in sub-G1 after transfection with control (Cy3) or p53 siRNAs and exposed to flavopiridol and 4OH-Tam for two days. Figure 7 Flavopiridol- and 4OH-Tam-induced caspase profiles in MON cells. A-D. Induction of caspase 8 (A), 9 (B), 2 (C), and 3 (D) activities after 24 hrs of treatment with flavopiridol, 4OH-Tam, or the combination and treated with either control (Cy3) or p53 siRNA.