Figure 5: Effect of midkine siRNA on doxorubicin resistant cellular response to doxorubicin. siRNA was used to knock down midkine expression in doxorubicin resistant SK-N-SH cells (DoxR) to determine if loss of midkine expression results in restoration of drug sensitivity in the DoxR cells. Wild type (WT), DoxR, DoxR cells treated with scramble sequence RNA (DoxR-scramble) and SK-N-SH DoxR cells treated with siRNA to midkine (DoxR-si-midkine) were cultured with or without doxorubicin at 10−7 M and 10−6 M for 24 hours. Cell survival was assayed using trypan blue and cell counting. Data represents the average of 4 experiments +/− SE.