Figure 2. Inhibition of Brn3a reduces melanoma cell viability and leads to reduced tumour growth in vivo.

1. 1205Lu melanoma cells were transfected with two siRNAs specific for Brn3a (Brn3a 1 and Brn3a 2) or control siRNAs and analysed by immunoblotting 48 h after transfection. Representative blots (n = 3) are shown.
2. Microscopic pictures of 1205Lu melanoma cells 2 or 4 days after transfection of Brn3a-specific siRNAs or control siRNA. Scale bars: 100 µm.
3. Different melanoma cell lines, i.e. 1205Lu, WM1158 and WM1232 (high Brn3a levels) and WM3211 (low Brn3a levels), were transfected with siRNAs as described in (A). Viable melanoma cells were quantified 4 days after siRNA transfection. Viability of cells treated with transfection reagent alone (‘no siRNA’) was set to 100%. Mean ± SD is shown. *p = 0.003 or less, t-test, n = 3 per group; n.s.: not significant (p > 0.05).
4. 1205Lu melanoma cells were subcutaneously injected into nude mice. Upon palpability of tumours, mice were systemically treated three times per week by intraperitoneal injection of 10 µg of Brn3a-specific or control siRNA complexed with polyethylenimine. Tumour growth in Brn3a siRNA-treated animals was significantly reduced (p = 0.0078, Wilcoxon matched pair test, n = 5 per group).
5. Brn3a mRNA levels in tumours isolated at day 29. Mean of each group ± SEM is shown.