Upregulation of ERBB3 by FOXD3, an adaptive response to RAF and MEK inhibitors

To understand the transcriptional impact of FOXD3 in melanoma cells, we utilized a microarray approach. We collected RNA from three unrelated mutant B-RAF melanoma cell lines (WM115, WM793, and A375) that were engineered to inducibly express FOXD3 or the control gene, β-galactosidase (LacZ), after 5 days of transgene induction. This time point was chosen based on maximal phenotypic changes previously observed. Comparison of gene signatures between the 3 cell lines produced approximately 2,600 common genes differentially regulated by FOXD3-expressing cells compared to the LacZ controls. Three unrelated mutant B-RAF melanoma cell lines (WM115, WM793, and A375) were induced to express FOXD3 and compared against the same cell lines expressing the control gene, β-galactosidase (LacZ).