Figure 4.

Silencing of ALDH1A1 and its impact on stem cell markers and cisplatin sensitivity in A2780 and A2780-Cp cell lines. A) Silencing mediated downregulation of ALDH1A1 expression in cisplatin sensitive and resistant A2780 cells. Relative expression for ALDH1A1 mRNA with respect to the gene GAPDH presented as fold change. All samples were run in triplicate and relative gene expressions were determined by 2^-ΔΔCt method with SYBR-green real-time PCR. Data were expressed as Mean ± SD. ∗∗P < 0.01 between control and siRNA treated cells. B) Reduction of ALDH positive population due to the silencing of ALDH1A1 gene in cisplatin resistant and supra resistant ovarian cancer cells. Cells were stained with ALDEFLUOR™ substrate represents a positive population, which is blocked by specific inhibitor DEAB. Data were expressed as Mean ± SD. ∗P < 0.05 between (i) A2780-A2780-Cp or (ii) SKOV3– SKOV3-Cp cells. C) Sensitization of ovarian cancer cells to cisplatin as a result of silencing ALDH1A1 with siRNA or inhibiting ALDH1 by DEAB. Cells were treated with 0.078 μM–40 μM concentrations of cisplatin for 48 h either treated with ALDH1A1 siRNA (i-ii) or DEAB (iii-iv). IC₅₀ values were determined from the dose-response non-linear curve fit prepared by GraphPad prism-5 using data from MTT assay.